Text

This is a digital document from the collections of the Wyoming Water Resources Data System (WRDS) Library.

For additional information about this document and the document conversion process, please contact WRDS at [email protected] and include the phrase “Digital Documents” in your subject heading. To view other documents please visit the WRDS Library online at: http://library.wrds.uwyo.edu

Mailing Address: Water Resources Data System University of Wyoming, Dept 3943 1000 E University Avenue Laramie, WY 82071 Physical Address: Wyoming Hall, Room 249 University of Wyoming Laramie, WY 82071 Phone: (307) 766-6651 Fax: (307) 766-3785

Funding for WRDS and the creation of this electronic document was provided by the Wyoming Water Development Commission (http://wwdc.state.wy.us)

INJECTION WELL INVENTORY OF WYOMING VOLUME I

M I C H A E L C O L L E N T I NE ROBERT L I B R A LYNNE BOYD C R A I G EISEN,

PROJECT MANAGER

WATER RESOURCES RESEARCH I N S T I T U T E U N I V E R S I T Y OF WYOMING L A R A M I E 1 WYOMING

JANUARY 1981

Acknowledgements S p e c i a l thanks a r e extended t o M r . Donald Basko, Flyoming O i l and Gas Commissioner, M r . Charles Farmer, Petroleum Engineer, M r s . Cheryl Dowler, and t h e e n t i r e s t a f f of t h e O i l and Gas Conservation Commission o f f i c e i n Casper, f o r t h e i r h e l p during t h e d a t a compilation phase of this project

.

INJECTION WELL INVENTORY OF WYOMING TABLE OF CONTENTS Volume I part I

INTRODUCTION.

....... Review of Current Technologies . . . . . . . . . P o t e n t i a l Environmental Impacts. . . . . . . . . P h y s i c a l D e s c r i p t i o n s of Petroleum R e l a t e d Injection Projects . . . . . . . . . . . . . . I N SITU URANIUM I N J E C T I O N PROJECTS. . . . . . . . . . Occurrence and C h a r a c t e r i s t i c s of Uranium D e p o s i t s . . . . . . . . . . . . . . . Review of Current Technologies . . . . . . . . . P o t e n t i a l Environmental Impacts. . . . . . . . . P h y s i c a l D e s c r i p t i o n s of I n S i t u Uranium Sites. . . . . . . . . . . . . . . . . . . . . I N SITU TRONA INJECTION PROJECTS. . . . . . . . . . . C h a r a c t e r i s t i c s of t h e Wyoming Trona Deposits . . . . . . . . . . . . . . . . . . . Review of Current Technologies . . . . . . . . . P o t e n t i a l Environmental Impacts. . . . . . . . . P h y s i c a l D e s c r i p t i o n s of I n S i t u Trona S i t e s . . UNDERGROUND COAL GASIFICATION PROJECTS. . . . . . . . Review of Current Technologies . . . . . . . . . P o t e n t i a l Environmental Impacts. . . . . . . . . P h y s i c a l D e s c r i p t i o n s of Underground Coal G a s i f i c a t i o n S i t e s . . . . . . . . . . . . CHEMICAL WASTE INJECTION SITES. . . . . . . . . . . . GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . LOCATION AND NUMBERING SYSTEM . . . . . . . . . . . .

PETROLEUM RELATED INJECTION OPERATIONS.

R E F E R E N C E S . . . . . . . . . . . . . . . . . . . . . .

MAP:

L o c a t i o n s and Types of I n j e c t i o n Operations inWyoming.

..................

iii

p a r t I1

p a r t 111

part I V

part V

v-1 v-3

part V I part V I I part V I I I part IX

map pocket

V o l u m e 11: D a t a T a b l e s

................. PETROLEUM RELATED I N J E C T I O N F A C I L I T I E S . . . . . . . . W a t e r Injection . . . . . . . . . . . . . . . . . G a s I n j e c t ion . . . . . . . . . . . . . . . . . . N a t u r a l G a s Storage . . . . . . . . . . . . . . . H y d r o t h e r m a l Injection . . . . . . . . . . . . . Water Disposal Systems . . . . . . . . . . . . . T e r t i a r y R e c o v e r y Projects . . . . . . . . . . . I N S I T U URANIUM MINING I N J E C T I O N F A C I L I T I E S . . . . . UNDERGROUND COAL GASIFICATION F A C I L I T I E S . . . . . . .

D E F I N I T I O N O F TERMS

page page page page page page

5 323 327 331 335 343

p a g e 347 page 353

I.

I N T R O D U C T I O N

T h i s " I n j e c t i o n Well Inventory of Wyomingt1 i s a d e t a i l e d review of underground i n j e c t i o n p r o j e c t s w i t h i n t h e s t a t e .

Included a r e :

(1) overviews of i n j e c t i o n t e c h n o l o g i e s employed by t h e petroleum, uranium, t r o n a , c o a l , and c h e m i c a l i n d u s t r i e s and t h e p o t e n t i a l environmental impacts a s s o c i a t e d w i t h such i n j e c t i o n s ; ( 2 ) p h y s i c a l d e s c r i p t i o n s of e x i s t i n g i n j e c t i o n f i e l d s w i t h i n Wyoming; and (3) a n inventory of t h e s e i n j e c t i o n w e l l s i n c l u d i n g w e l l l o c a t i o n , depth, i n j e c t e d formation, and o t h e r p e r t i n e n t d a t a .

Technology reviews and s i t e

d e s c r i p t i o n s of i n j e c t i o n o p e r a t i o n s a r e contained i n Volume I of t h e r e p o r t , w h i l e t h e i n j e c t i o n w e l l inventory of each o p e r a t i o n i s contained i n Volume 11. T h i s s t u d y was funded by t h e U.S. Environmental P r o t e c t i o n Agency under c o n t r a c t no. GO-082-697-90, Control Program (UIC). Act (P.L.

93-523),

f o r t h e Underground I n j e c t i o n

The U I C , a u t h o r i z e d by t h e S a f e Drinking Water

i s designed t o improve t h e p r o t e c t i o n of ground-

water r e s o u r c e s from p o s s i b l e contamination caused by i n j e c t i o n of b r i n e s , sewage, and o t h e r f l u i d s .

T h i s r e p o r t , w i t h i t s compilation

of roughly 4,000 petroleum i n d u s t r y r e l a t e d i n j e c t i o n w e l l s , 350 i n s i t u uranium i n j e c t i o n w e l l s , and 400 underground c o a l g a s i f i c a t i o n i n j e c t i o n w e l l s , d e s c r i b e s t h e c u r r e n t magnitude and d i s t r i b u t i o n of underground i n j e c t i o n a c t i v i t i e s w i t h i n t h e s t a t e , and w i l l h o p e f u l l y s e r v e a s a background s o u r c e d i r e c t o r y f o r t h e U I C program.

11.

PETROLEUM

I N J E C T I O N

RELATED

O P E R A T I O N S

REVIEW OF CURRENT TECHNOLOGIES During t h e l a s t 50 y e a r s , t h e o i l i n d u s t r y of t h e United S t a t e s has placed i n c r e a s i n g emphasis on secondary and t e r t i a r y methods of o i l production due t o t h e i n c r e a s e d p r i c e of o i l , t h e i n c r e a s e d c o s t s of e x p l o r a t i o n , and t h e low frequency of l a r g e domestic r e s e r v o i r discove r i e s ( I n t e r s t a t e O i l Compact Commission, 1974).

I n 1974, t h e I n t e r s t a t e

O i l Compact Commission estimated t h a t by 1980, over h a l f of t h e o i l

produced i n t h e United S t a t e s , e x c l u s i v e of t h e North Slope of Alaska, would be produced by secondary and t e r t i a r y recovery methods. Secondary and t e r t i a r y recovery a r e d e f i n e d h e r e i n a s t h e o i l and/or gas recovered by a r t i f i c i a l flowing o r pumping means, through t h e j o i n t u s e of two o r more w e l l bores (Smith, 1966).

The purpose of a

secondary o r t e r t i a r y recovery p r o j e c t is t o d i s p l a c e a s much o i l a s p o s s i b l e from t h e r e s e r v o i r t o t h e producing w e l l ( s ) .

I n order t o

e f f e c t an economical recovery, t h e i n j e c t e d f l u i d must be capable of d i s p l a c i n g o i l from t h e pores of water-wet r e s e r v o i r rock and/or breaki n g down t h e c a p i l l a r y f o r c e s between rock g r a i n s and t h e f i l m of o i l around t h e g r a i n s i n oil-wet r e s e r v o i r rock.

An enhanced recovery

o p e r a t i o n should be designed t o supplement t h e n a t u r a l r e s e r v o i r d r i v e mechanism(s) t h a t provides f o r t h e primary o i l recovery. The t y p e s of i n j e c t i o n o p e r a t i o n s t h a t w i l l be d i s c u s s e d i n t h i s s e c t i o n include:

(1) water and gas i n j e c t i o n (secondary recovery

methods); ( 2 ) steam i n j e c t i o n (advanced secondary recovery method);

(3) polymer, m i s c i b l e f l u i d , and microemulsion i n j e c t i o n ( t e r t i a r y r e c o v e r y methods); (4) s a l t w a t e r d i s p o s a l ; and (5) n a t u r a l g a s s t o r a g e .

Primary R e s e r v o i r D r i v e Mechanisms The mechanisms by which gas and o i l a r e n a t u r a l l y d i s p l a c e d through t h e r e s e r v o i r t o t h e producing w e l l s a r e c a l l e d t h e primary r e s e r v o i r d r i v e mechanisms.

They i n c l u d e :

(1) f l u i d and rock expansion;

( 2 ) n a t u r a l f l u i d d i s p l a c e m e n t ; and (3) g r a v i t a t i o n a l d r a i n a g e . F l u i d and rock expansion energy i s produced by t h e expansion of hydrocarbon f l u i d s and sediment g r a i n s w i t h i n t h e r e s e r v o i r m a t r i x a s o i l a n d / o r g a s a r e produced.

A s reservoir pressure decreases, f l u i d

p r e s s u r e w i t h i n t h e p o r e s p a c e s i s reduced, d e c r e a s i n g t h e b u l k volume of t h e r o c k , and i n c r e a s i n g t h e volume of i n d i v i d u a l rock g r a i n s . The combination of t h e b u l k rock volume r e d u c t i o n and t h e s o l i d rock m a t e r i a l expansion r e d u c e s t h e p o r o s i t y of t h e rock by approximately 0.5 p e r c e n t f o r each change of 1,000 p s i i n t h e i n t e r n a l f l u i d p r e s s u r e ( C r a f t and Hawkins, 1959).

A s p o r o s i t y d e c r e a s e s , hydrocarbons a r e

d r i v e n o u t of t h e p o r e s p a c e s toward t h e producing w e l l . There a r e t h r e e t y p e s of f l u i d displacement d r i v e mechanisms: s o l u t i o n g a s d r i v e ; (2) w a t e r d r i v e ; and ( 3 ) g a s cap d r i v e .

(1)

Solution

gas d r i v e o c c u r s i n r e s e r v o i r s t h a t have no g a s cap and a r e i s o l a t e d from w a t e r encroachment.

The decreased r e s e r v o i r p r e s s u r e r e s u l t i n g

from p r o d u c t i o n a l l o w s g a s e s d i s s o l v e d i n o i l and w a t e r t o come o u t of s o l u t i o n and d i s p l a c e o i l toward producing w e l l s .

Primary r e c o v e r y

from s o l u t i o n g a s d r i v e r e s e r v o i r s i s normally 5 t o 30 p e r c e n t of t h e o r i g i n a l o i l i n place. Water d r i v e i s a n a t u r a l d r i v e mechanism caused by t h e encroachment of w a t e r i n t o t h e r e s e r v o i r from an a d j a c e n t a q u i f e r a s g a s and o i l

a r e produced and r e s e r v o i r p r e s s u r e d e c l i n e s .

Primary r e c o v e r y from a

w a t e r d r i v e n r e s e r v o i r may b e a s h i g h a s 35 t o 75 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e ( C l a r k , 1969). Gas cap d r i v e i s t h e r e s e r v o i r energy produced by expansion of t h e g a s cap due t o p r o d u c t i o n and subsequent d e c l i n e s i n r e s e r v o i r p r e s s u r e . The expanding g a s cap, which o v e r l i e s t h e o i l and w a t e r zones of t h e r e s e r v o i r , d i s p l a c e s o i l downward toward t h e producing w e l l s .

Primary

r e c o v e r y from a g a s cap d r i v e n r e s e r v o i r u s u a l l y r a n g e s from 20 t o 40 p e r c e n t and may b e a s h i g h a s 60 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e . G r a v i t a t i o n a l d r a i n a g e o r g r a v i t a t i o n a l s e g r e g a t i o n may b e cons i d e r e d a d r i v e mechanism, b u t i s u s u a l l y a p a r t of o t h e r d r i v e t y p e s . It i s caused by t h e s e g r e g a t i o n of r e s e r v o i r f l u i d s ( o i l , g a s , and w a t e r ) ,

a s t h e r e s e r v o i r p r e s s u r e i s d e c r e a s e d by p r o d u c t i o n .

The f l u i d s t h e n

s e e k a new e q u i l i b r i u m d i s t r i b u t i o n a c c o r d i n g t o d e n s i t y .

Geologic and Hydrologic C o n t r o l s on O i l Recovery E f f i c i e n c y S t r u c t u r e , s t r a t i g r a p h y , h y d r a u l i c g r a d i e n t , p o r o s i t y , and permea b i l i t y p l a y major r o l e s i n t h e m o b i l i t y of b o t h r e s e r v o i r and i n j e c t e d f l u i d s and t h e b u l k volume of t h e r e s e r v o i r c o n t a c t e d by t h e i n j e c t e d f l u i d s (IOCC, 1974)

.

O i l r e c o v e r y e f f i c i e n c y i s a f u n c t i o n of b o t h t h e displacement

e f f i c i e n c y ( t h e p e r c e n t a g e of o i l i n p l a c e t h a t t h e i n j e c t e d f l u i d sweeps from a u n i t volume of t h e r e s e r v o i r ) and t h e v o l u m e t r i c sweep e f f i c i e n c y ( t h e p e r c e n t a g e of t h e t o t a l r e s e r v o i r volume t h a t i s c o n t a c t e d by t h e i n j e c t e d f l u i d ) (IOCC, 1974). The d i s p l a c e m e n t e f f i c i e n c y of t h e i n j e c t e d f l u i d i s dependent upon t h e s a t u r a t i o n t y p e (water-wet o r o i l - w e t ) ,

and the r e l a t i v e

p e r m e a b i l i t y c h a r a c t e r i s t i c s of t h e r e s e r v o i r .

I n a r e s e r v o i r where

t h e sediment g r a i n s a r e surrounded by a f i l m of water (water-wet r e s e r v o i r ) , o i l i s r e a d i l y d i s p l a c e d by t h e i n j e c t i o n of water o r gas; however, where t h e sediment g r a i n s have o i l f i l m s (oil-wet r e s e r v o i r ) , t h e i n j e c t e d f l u i d must be capable of breaking down t h e c a p i l l a r y f o r c e s t h a t e x i s t between t h e g r a i n s and t h e o i l i n o r d e r t o r e a l i z e economic o i l r e c o v e r i e s (IOCC, 1974).

The a b i l i t y of t h e porous

r e s e r v o i r r o c k t o conduct a f l u i d i n t h e presence of one o r more o t h e r f l u i d s is a composite e f f e c t of pore geometry, r e s e r v o i r s a t u r a t i o n t y p e ( e i t h e r water-wet o r o i l - w e t ) , s a t u r a t i o n h i s t o r y (Smith, 1966).

f l u i d d i s t r i b u t i o n , and

The p e r m e a b i l i t y c h a r a c t e r i s t i c s of

a r e s e r v o i r a r e a major f a c t o r involved i n t h e determination of t h e type of f l u i d i n j e c t e d i n a secondary o r t e r t i a r y recovery o p e r a t i o n .

For

example, a r e s e r v o i r w i t h poor p e r m e a b i l i t y c h a r a c t e r i s t i c s would be i n j e c t e d w i t h gas r a t h e r than w a t e r , due t o t h e low r e l a t i v e v i s c o s i t y and h i g h r e l a t i v e m o b i l i t y of t h e gas i n a low p e r m e a b i l i t y r e s e r v o i r . A procedure f o r determining t h e r e l a t i v e p e r m e a b i l i t y c h a r a c t e r i s t i c s ,

t o o d e t a i l e d f o r t h e purposes of t h i s r e p o r t , is o u t l i n e d i n IOCC (1974). The volumetric sweep e f f i c i e n c y of t h e i n j e c t e d f l u i d i s d i r e c t l y a f f e c t e d by t h e m o b i l i t y r a t i o and t h e i n j e c t i o n w e l l p a t t e r n . Mobility r a t i o i s defined a s " t h e r a t i o of t h e i n j e c t e d f l u i d m o b i l i t y i n t h e p o r t i o n of t h e r e s e r v o i r contacted by t h e i n j e c t e d f l u i d , t o t h e o i l m o b i l i t y i n t h e non-invaded p o r t i o n of t h e r e s e r v o i r 1 ' ( I O C C , 1974). The m o b i l i t y of a f l u i d i s t h e p e r m e a b i l i t y of t h e rock t o t h a t f l u i d , divided by t h e v i s c o s i t y of t h e f l u i d . decreases with increasing o i l v i s c o s i t y .

Thus, t h e m o b i l i t y r a t i o

The i n j e c t i o n w e l l p a t t e r n i s , simply, t h e c o n f i g u r a t i o n of i n j e c t i o n w e l l l o c a t i o n s r e l a t i v e t o production w e l l l o c a t i o n s . i d e a l i n j e c t i o n p a t t e r n f o r any o i l f i e l d is one t h a t :

The

(1) provides

t h e u l t i m a t e o i l recovery c a p a c i t y ; ( 2 ) provides a s u f f i c i e n t r a t e of f l u i d i n j e c t i o n t o a t t a i n t h i s o i l recovery; ( 3 ) maximizes t h e o i l recovery w i t h a minimum of produced f l u i d t o l i f t and d i s p o s e ; (4) u t i l i z e s known o r i e n t a t i o n s of r e s e r v o i r p e r m e a b i l i t y i r r e g u l a r i t i e s , f r a c t u r e s and s t r a t i f i c a t i o n ; (5) u t i l i z e s e x i s t i n g w e l l s , minimizing t h e d r i l l i n g of new i n j e c t i o n w e l l s ; and (6) i s compatible w i t h t h e f l o o d i n g p a t t e r n s of o p e r a t o r s on a d j a c e n t l e a s e s . Among t h e most commonly used w e l l p a t t e r n s i n Wyoming a r e t h e five-spot,

seven-spot,

peripheral patterns. F i g u r e 1.

i n v e r t e d seven-spot, nine-spot,

l i n e d r i v e , and

Diagrams of t h e s e p a t t e r n s a r e i l l u s t r a t e d i n

The f i v e - s p o t p a t t e r n i s t h e most popular c o n f i g u r a t i o n i n

Wyoming and t h e r e s t of t h e United S t a t e s due t o i t s e f f i c i e n t f l o o d i n g performance and t h e e a s e of w e l l c o n v e r t i b i l i t y from d r y h o l e s and m a r g i n a l l y economical production w e l l s t o t h e f i v e - s p o t c o n f i g u r a t i o n of i n j e c t i o n w e l l s .

The f i v e - s p o t p a t t e r n i s u t i l i z e d where r e s e r v o i r

p e r m e a b i l i t y i s v a r i a b l e , i n o r d e r t o i s o l a t e known r e s e r v o i r nonuniformities.

The seven- and nine-spot p a t t e r n s a r e u t i l i z e d under

f i e l d c o n d i t i o n s s i m i l a r t o t h o s e of t h e f i v e - s p o t p a t t e r n , b u t where t h e conversion of w e l l s i s n o t conducive t o t h e f i v e - s p o t .

Peripheral

and l i n e d r i v e p a t t e r n s a r e employed where t h e i n j e c t e d r e s e r v o i r h a s a c o n s i s t e n t , u n i d i r e c t i o n a l f r a c t u r e o r permeability o r i e n t a t i o n (IOCC

, 1974) .

Five-spot Pattern

Seven-spot Pattern

II

P

I I

I1 I

I

I---I---I---

t

I

?

I

PI l nverted Seven-spot Pat tern

I I

P

P

I

I I

I

I---I I

I

P

I

I

I

I I

P

I

I

Nine-spot Pattern

Direct Line Drive Pattern

I p ---

F i g u r e 1.

Injection Well

Peripheral Pattern

Production Well Pattern Boundaries

I n j e c t i o n w e l l p a t t e r n s (from IOCC, 1974, pp. 15 and 1 6 ) .

D r i l l i n g and Casing of I n j e c t i o n Wells Before a f l u i d i n j e c t i o n p r o j e c t can go i n t o o p e r a t i o n , t h e i n j e c t i o n w e l l ( s ) must be d r i l l e d and cased i n a manner t h a t i n s u r e s both t h e p r o t e c t i o n of t h e environment a g a i n s t i n a d v e r t e n t p o l l u t i o n and t h e Whether i t i s designed

maximum u t i l i t y of t h e w e l l ( s ) (Barlow, 1972).

f o r d i s p o s a l of b r i n e s , water i n j e c t i o n , o r microemulsion i n j e c t i o n , t h e w e l l ( s ) must be designed t o p r o t e c t t h e n e a r s u r f a c e , fresh-water a q u i f e r s through which i t i s d r i l l e d .

An i d e a l i z e d schematic drawing

of an i n j e c t i o n w e l l i s i l l u s t r a t e d i n F i g u r e 2 . The borehole of t h e i n j e c t i o n w e l l i s commonly 12 t o 18 inches i n diameter and d r i l l e d t o a t l e a s t 200 f e e t below t h e deepest fresh-water aquifer.

S u r f a c e c a s i n g , of a diameter a t l e a s t 2 inches l e s s than

t h e diameter of t h e h o l e and equipped w i t h c e n t r a l i z e r s , i s run t o t h e bottom of t h e h o l e .

The a n n u l a r space between t h e borehole and t h e

s u r f a c e c a s i n g i s t h e n f i l l e d w i t h cement.

Experience with b r i n e

i n j e c t i o n w e l l s h a s shown t h i s procedure t o b e e f f e c t i v e i n p r o t e c t i n g t h e cased-off

fresh-water a q u i f e r s i n t h e event of damage t o t h e

i nj e c t i o n c a s i n g . A f t e r t h e s u r f a c e c a s i n g i s i n s t a l l e d , a 7 t o 12 i n c h diameter h o l e i s d r i l l e d from t h e bottom of t h e s u r f a c e c a s i n g t o t h e depth of t h e formation t h a t w i l l r e c e i v e t h e i n j e c t i o n f l u i d s .

Borehole t e s t s ,

i n c l u d i n g c o r e s , e l e c t r i c l o g s , c a l i p e r l o g s , e t c . , a r e run on t h e h o l e p r i o r t o running t h e i n j e c t i o n c a s i n g s t r i n g .

The i n j e c t i o n (long)

s t r i n g i s u s u a l l y 5% t o 9 i n c h e s i n diameter.

After the injection

s t r i n g i s c e n t e r e d , cement i s c i r c u l a t e d t o a t l e a s t 1,500 t o 2,000 f e e t above t h e t o t a l depth of t h e w e l l i n t h e annulus between t h e c a s i n g and t h e w e l l b o r e .

Depending on t h e n a t u r e of t h e i n j e c t i o n zone

Figure 2.

I d e a l i z e d schematic drawing of an i n j e c t i o n w e l l (from Donaldson, E. C., 1972).

rock, t h e w e l l i s completed by p e r f o r a t i n g t h e cement i n a f r i a b l e f o r mation, by open h o l e i n a hard c o n s o l i d a t e d sandstone o r vugular limes t o n e , o r by g r a v e l packing i n an unconsolidated sandstone i n t e r v a l . Secondary Enhancement of Primary Reservoir Drive Mechanisms Water I n i e c t i o n Water i n j e c t i o n i s an o i l recovery enhancement technique t h a t i n v o l v e s t h e i n j e c t i o n of produced o r non-produced water through w e l l s i n t o an o i l producing r e s e r v o i r i n o r d e r t o :

( I ) d i s p l a c e o i l from t h e r e s e r v o i r

t o producing w e l l s a s t h e primary production energy of t h e r e s e r v o i r d e c l i n e s ; and (2) t o m a i n t a i n o r i n c r e a s e r e s e r v o i r p r e s s u r e . The water i n j e c t i o n p r o c e s s was f i r s t used by a c c i d e n t , a t a f i e l d Water from a shallow a q u i f e r

i n western Pennsylvania over 100 y e a r s ago.

leaked around a poorly s e a l e d packer, e n t e r e d t h e w e l l ' s o i l column and, though i t e l i m i n a t e d production from t h a t w e l l , production of o i l from surrounding w e l l s i n c r e a s e d n o t i c e a b l y .

It wasn't u n t i l t h e 1890's t h a t

t h e f i r s t waterflood t e s t p r o j e c t i n Wyoming was i n i t i a t e d a t S a l t Creek F i e l d i n t h e second Wall Creek sand.

Cole Creek F i e l d was t h e s i t e of

t h e n e x t w a t e r f l o o d t e s t i n Wyoming i n 1946.

A s of December, 1979,

t h e Wyoming O i l and Gas Conservation Commission r e p o r t e d 235 water injection projects operating i n the s t a t e . There a r e n i n e g e n e r a l f i e l d c h a r a c t e r i s t i c s considered f a v o r a b l e f o r a water i n j e c t i o n p r o j e c t .

They a r e :

(1) r e s e r v o i r t h i c k n e s s

g r e a t e r than t e n f e e t and depth l e s s than 10,000 f e e t ; (2) sandstone r e s e r v o i r t h a t does n o t c o n t a i n major f r a c t u r e p o r o s i t y ; (2) o i l s a t u r a t i o n g r e a t e r t h a n 40 p e r c e n t of pore volume; (4) water s a t u r a t i o n l e s s than 45 p e r c e n t of pore volume; (5) s o l u t i o n gas d r i v e ; (6)

o n l y moderate amounts of l e n t i c u l a r i t y ; ( 7 ) a p e r m e a b i l i t y p r o f i l e t h a t i s n o t extremely e r r a t i c ; (8) v i s c o s i t y of o i l , a t r e s e r v o i r c o n d i t i o n s ,

of less t h a n 30 c e n t i p o i s e ; and (9) good w a t e r q u a l i t y and an a d e q u a t e w a t e r s u p p l y (Recluse F i e l d Engineering and Geologic R e p o r t , O i l and Gas Commission F i l e s ) .

I d e a l l y , w a t e r i s i n j e c t e d i n t o t h e producing r e s e r v o i r and m i g r a t e s through t h e permeable r o c k , d i s p l a c i n g immiscible r e s e r v o i r f l u i d s from t h e p o r e s p a c e s toward t h e producing w e l l s . The o i l r e c o v e r y e f f i c i e n c y of a w a t e r f l o o d o p e r a t i o n i s p r i m a r i l y dependent upon t h e t y p e of r e s e r v o i r s a t u r a t i o n and t h e r e s e r v o i r permeability c h a r a c t e r i s t i c s .

For example, a n oil-wet r e s e r v o i r ,

w a t e r f l o o d e d f o r more t h a n a y e a r , might r e t a i n a s i g n i f i c a n t p e r c e n t a g e of t h e o r i g i n a l o i l i n p l a c e bound t o t h e r o c k g r a i n s u r f a c e s by capillary forces.

To remove t h e remaining o i l , t e r t i a r y r e c o v e r y

methods, u t i l i z i n g f l u i d s ( s u r f a c t a n t s , microemulsions, e t c . ) c a p a b l e of overcoming t h o s e f o r c e s , a r e n e c e s s a r y .

The r e c o v e r y e f f i c i e n c y from

a water-wet

r e s e r v o i r would depend more upon t h e p e r m e a b i l i t y of t h e

reservoir.

A g r e a t e r p e r c e n t a g e of in-place o i l i s d i s p l a c e d by water

i n t h i s t y p e of r e s e r v o i r , t h e c o n t r o l l i n g f a c t o r b e i n g t h e p e r c e n t a g e of r e s e r v o i r volume c o n t a c t e d by t h e i n j e c t e d w a t e r . The water used f o r secondary o i l r e c o v e r y o p e r a t i o n s may b e r e s e r v o i r b r i n e s e p a r a t e d from produced o i l , b r i n e produced from a w a t e r s a t u r a t e d p o r t i o n of t h e produced r e s e r v o i r , a n d / o r " f r e s h " w a t e r produced from a w a t e r s a t u r a t e d f o r m a t i o n n o t a s s o c i a t e d w i t h t h e o i l producing r e s e r v o i r .

The t y p e of w a t e r used depends upon t h e

a v a i l a b i l i t y of f r e s h water and t h e c o m p a t i b i l i t y of a v a i l a b l e water w i t h t h e c o n n a t e f l u i d s and mineralogy of t h e i n j e c t e d f o r m a t i o n (IOCC, 1960).

Gas I n j e c t i o n Gas i n j e c t i o n i s a p r o c e s s s i m i l a r t o water i n j e c t i o n , u t i l i z i n g produced g a s t o d i s p l a c e o i l from t h e r e s e r v o i r t o producing w e l l s . The a v a i l a b i l i t y of g a s and r e l a t i v e e a s e of i n j e c t i o n make t h e secondary o i l recovery technique of g a s i n j e c t i o n an a t t r a c t i v e o p t i o n under favorable reservoir conditions. I n a r e s e r v o i r i n which t h e f l u i d s a r e segregated by d e n s i t y and which h a s a p e r m e a b i l i t y of a t l e a s t 200 m i l l i d a r c i e s , g a s i s most o f t e n i n j e c t e d i n t o t h e c r e s t o r g a s cap of t h e r e s e r v o i r .

The expan-

s i o n of t h e g a s d i s p l a c e s o i l downward toward t h e producing w e l l s , u s u a l l y r e s u l t i n g i n h i g h o i l recovery e f f i c i e n c y .

A t f i e l d s where

producing o i l w e l l s were converted t o i n j e c t i o n w e l l s , gas i s i n j e c t e d i n t o t h e r e s e r v o i r a t a p o i n t below t h e gas cap.

The i n j e c t e d gas then

r i s e s toward t h e gas cap, d i s p l a c i n g oil toward t h e producing w e l l s (IOCC, 1974).

I n r e s e r v o i r s t h a t lack s u f f i c i e n t permeability f o r

g r a v i t y d r i v e t o o p e r a t e , a f r o n t a l d r i v e o r d i s p e r s e d gas i n j e c t i o n , similar t o t h a t used f o r w a t e r f l o o d s , may b e e f f e c t i v e , e s p e c i a l l y i n r e s e r v o i r s t h a t have a l r e a d y been produced by s o l u t i o n gas d r i v e (IOCC , 1974)

.

There a r e two n o t a b l e disadvantages t o secondary o i l recovery by gas i n j e c t i o n .

They a r e :

(1) t h e low v i s c o s i t y of g a s r e s u l t s i n

poor displacement e f f i c i e n c y ; and (2) t h e h e t e r o g e n e i t y of p e r m e a b i l i t y , i n most r e s e r v o i r s , r e s u l t s i n e a r l y breakthrough of i n j e c t e d g a s t o producing w e l l s .

Steam I n j e c t i o n The steam i n j e c t i o n process is s i m i l a r t o water and gas i n j e c t i o n i n t h a t steam i s i n j e c t e d i n t o w e l l s completed i n t h e producing r e s e r v o i r , and t h a t o i l i s produced from o t h e r w e l l s placed i n an e f f e c t i v e p a t t e r n around t h e i n j e c t i o n w e l l s .

The i n j e c t i o n of steam

i s most e f f e c t i v e i n r e s e r v o i r s w i t h high v i s c o s i t y (low g r a v i t y ) o i l

(IOCC, 1974). Steam i n j e c t i o n tests were i n i t i a l l y conducted during t h e 1920's and 1930's.

The process gained prominence during t h e 1960's when S h e l l

O i l conducted a s u c c e s s f u l o p e r a t i o n i n C a l i f o r n i a .

Today, steam

i n j e c t i o n i s regarded a s a w e l l e s t a b l i s h e d method of advanced secondary o i l recovery. The following a r e r e s e r v o i r c h a r a c t e r i s t i c s and design c r i t e r i a d e s i r a b l e f o r a steam i n j e c t i o n o p e r a t i o n , a s o u t l i n e d by t h e I n t e r s t a t e O i l Compact Commission (1974, pp. 159-160):

The depth of t h e i n j e c t e d formation should be l e s s t h a n 3,000 f e e t . The i n j e c t i o n depth cannot exceed 5,000 f e e t , s i n c e t h e c r i t i c a l p r e s s u r e of steam i s 3,202 pounds per s q u a r e i n c h . Formation t h i c k n e s s should not exceed 30 f e e t i n o r d e r t o minimize h e a t l o s s . Formation p e r m e a b i l i t y should exceed 1,000 m i l l i d a r c i e s . Formation p o r o s i t y should b e approximately 30 p e r c e n t . The g r a v i t y and v i s c o s i t y of t h e o i l should be 12 t o 25' API and ~ ~ 1 , 0 0c0e n t i p o i s e , r e s p e c t i v e l y , a t r e s e r v o i r temperature. Steam should be i n j e c t e d n e a r t h e base of t h e o i l zone.

With t h e i n j e c t i o n of steam i n t o an o i l r e s e r v o i r , s e v e r a l f l u i d zones a r e formed between t h e i n j e c t i o n w e l l bore and t h e o i l producing

w e l l a s h e a t i s l o s t t o t h e surrounding rock m a t e r i a l . surrounding t h e w e l l bore i s a steam s a t u r a t e d zone. s a t u r a t e d zone i s a zone of condensed steam.

Immediately Beyond t h e steam

I n t h e zone of steam

s a t u r a t i o n , because of t h e presence of a gas phase, steam d i s t i l l a t i o n of t h e o i l t a k e s p l a c e .

I n t h e h o t water zone i n f r o n t of t h e steam

zone, a h o t water f l o o d occurs.

O i l displacement from t h i s zone r e s u l t s

from a r e d u c t i o n of o i l v i s c o s i t y , and thermal expansion of o i l a t high temperatures, which l e a d s t o a r e d u c t i o n of r e s i d u a l o i l s a t u r a t i o n and changes i n t h e r e l a t i v e p e r m e a b i l i t y c h a r a c t e r i s t i c s . e f f e c t i s poorly understood.

The l a t t e r

F u r t h e r displacement of o i l occurs i n t h e

cold water zone which precedes t h e hot water zone. T e r t i a r y Enhancement of Primary Drive Mechanisms T e r t i a r y recovery of o i l d i f f e r s from secondary recovery only i n t h e type of f l u i d i n j e c t e d .

Rather than d i s p l a c i n g o i l from t h e pores

of t h e o i l r e s e r v o i r rock, a s i n water and gas i n j e c t i o n p r o c e s s e s , t e r t i a r y f l u i d s work a s a c t i v e a g e n t s which break down t h e c a p i l l a r y f o r c e s binding o i l t o t h e rock g r a i n s of t h e r e s e r v o i r .

I n Wyoming,

t h r e e t y p e s of t e r t i a r y recovery processes a r e now being u t i l i z e d . are:

They

microemulsion f l o o d i n g , m i s c i b l e f l u i d i n j e c t i o n , and polymer

solution injection. The most r e c e n t breakthrough i n o i l recovery processes i s microemulsion f l o o d i n g , a miscible-type displacement process c h a r a c t e r i z e d by 100 p e r c e n t displacement of oil i n t h e r e s e r v o i r contacted (IOCC, 1974).

Microemulsions a r e s u r f a c t a n t s t a b i l i z e d d i s p e r s i o n s of

hydrocarbons and water which, a t high c o n c e n t r a t i o n s , form aggregates calledmicelles. t h e i r cores.

These m i c e l l e s a r e capable of s o l u b i l i z i n g f l u i d i n t o

Alcohols and s a l t s a r e a l s o added t o c o n t r o l s t a b i l i t y ,

v i s c o s i t y , and o t h e r c h a r a c t e r i s t i c s of t h e microemulsion. Microemulsion f l o o d i n g i s a three-step procedure c o n s i s t i n g of t h e i n j e c t i o n of a microemulsion s l u g , followed by t h e i n j e c t i o n of a "mobility b u f f e r s o l u t i o n , " which i s , i n t u r n , followed by t h e i n j e c t i o n of water (IOCC, 1974).

The m o b i l i t y b u f f e r s o l u t i o n i s i n j e c t e d

a f t e r t h e s l u g of microemulsion t o prevent r a p i d d i s p e r s i o n and t h u s minimize t h e volume of microemulsion r e q u i r e d f o r an e f f e c t i v e f l o o d . Besides t h e i r h i g h displacement e f f i c i e n c y , microemulsions a l s o have a h i g h volumetric sweep e f f i c i e n c y .

The m o b i l i t y c o n t r o l of

microemulsion s o l u t i o n s i n h i b i t s t h e r a p i d d i s s i p a t i o n of t h e microemulsion i n j e c t e d by preventing "fingering" through t h e r e s e r v o i r , t h u s i n c r e a s i n g t h e sweep e f f i c i e n c y ( I O C C , 1974). The microemulsion f l o o d i n g method i s a p p l i c a b l e wherever a water i n j e c t i o n p r o j e c t has been s u c c e s s f u l and, i n some i n s t a n c e s , even where water i n j e c t i o n p r o j e c t s f a i l e d due t o poor displacement of o i l by water.

The economics of microemulsion f l o o d i n g depend p r i m a r i l y on

t h e chemical requirement, c o s t of chemicals, and o i l s a t u r a t i o n i n t h e r e s e r v o i r a t t h e time t h e flood i s i n i t i a t e d . M i s c i b l e f l u i d i n j e c t i o n i s another r e c e n t l y developed t e r t i a r y o i l recovery process, i n v o l v i n g an o i l d i s s o l v i n g s o l v e n t capable of complete displacement of o i l from t h e contacted a r e a s of a r e s e r v o i r . The m i s c i b l e s o l v e n t may be an a l c o h o l , a ketone, a number of r e f i n e d hydrocarbons, a condensed petroleum g a s , carbon d i o x i d e , o r exhaust gas.

The procedure followed i n a m i s c i b l e f l u i d i n j e c t i o n o p e r a t i o n c o n s i s t s of two s t e p s .

F i r s t , a s l u g of s o l v e n t , m i s c i b l e w i t h t h e type

of o i l i n t h e r e s e r v o i r , i s i n j e c t e d .

Second, a f l u i d o r g a s , capable

of d i s p l a c i n g t h e s o l v e n t and o i l toward t h e producing w e l l s , i s i n j e c t e d (IOCC, 1974). I n r e s e r v o i r s w i t h h i g h v i s c o s i t y o i l s , waterflood recovery e f f i c i e n c y may be g r e a t l y improved by t h e a d d i t i o n of polymers o r s i m i l a r chemicals, which i n c r e a s e t h e v i s c o s i t y of t h e i n j e c t e d water. Polymer i n j e c t i o n advantages i n c l u d e a r e d u c t i o n i n t h e amount of water r e q u i r e d f o r t h e flood and an i n c r e a s e i n t h e volumetric sweep e f f i c i e n c y due t o a reduced, and t h u s improved, waterflood m o b i l i t y r a t i o (IOCC, 1974).

However, t h e c o s t of i n c r e a s i n g t h e v i s c o s i t y of water

i n some r e s e r v o i r s may outweigh t h e advantages. S a l t Water Disposal I n most hydrocarbon r e s e r v o i r s , o i l and gas were trapped i n t h e presence of s t r o n g l y s a l i n e o r b r i n e w a t e r s .

The most environmentally

s a t i s f a c t o r y method f o r t h e d i s p o s a l of o i l f i e l d b r i n e s has been t o i n j e c t them t o a s u b s u r f a c e formation below t h e d e e p e s t known f r e s h water a q u i f e r (IOCC, 1960).

The s u b s u r f a c e formation may be t h e

r e s e r v o i r from which t h e b r i n e s were o r i g i n a l l y produced ( s e e water i n j e c t i o n s e c t i o n ) , o r i t may be one of t h e non-productive s a l i n e water-bearing formations normally p r e s e n t i n a producing r e g i o n . I d e a l l y , t h e b r i n e i s i n j e c t e d i n t o a formation from which t h e f l u i d

i s unable t o m i g r a t e v e r t i c a l l y .

An impermeable zone of s h a l e o r

e v a p o r i t e i s d e s i r a b l e above and below t h e i n j e c t e d formation.

The l i f e of t h e d i s p o s a l system i n a confined formation i s l i m i t e d by t h e cumulative i n c r e a s e i n h y d r o s t a t i c p r e s s u r e through compression of i n t e r s t i t i a l f l u i d s (gas and b r i n e ) and t h e rock m a t r i x , a s b r i n e i s i n j e c t e d i n t o t h e formation.

Reservoir p r e s s u r e g r a d u a l l y i n c r e a s e s

t o a p o i n t where continued i n j e c t i o n i s environmentally dangerous because of p o s s i b l e f r a c t u r i n g of t h e confining s t r a t a and r e l e a s e of the b r i n e t o overlying aquifers.

The f r a c t u r i n g p r e s s u r e of t h e

i n j e c t e d formation, t h e r e f o r e , d e f i n e s t h e l i m i t s on t h e period and r a t e of i n j e c t i o n i f no f l u i d s a r e withdrawn from t h e r e s e r v o i r (Donaldson, 1972)

.

John Galley (1968, pp. 119-125) o u t l i n e d t h e f a v o r a b l e g e o l o g i c s e t t i n g f o r s a l t water d i s p o s a l w e l l s i n f o u r p o i n t s :

(1) porous and

permeable r e s e r v o i r rocks i n which t h e s t o r a g e space may b e caverns, i n t e r g r a n u l a r p o r e s , o r f r a c t u r e c r e v i c e s ; (2) impermeable s e a l s t o prevent escape of f l u i d wastes;

( 3 ) adequate understanding of hydrologic

parameters and planning t o prevent u n d e s i r a b l e m i g r a t i o n of f l u i d s ; and (4) c o m p a t i b i l i t y between waste m a t e r i a l s , t h e r e s e r v o i r r o c k s , and t h e i r n a t u r a l f l u i d s . N a t u r a l Gas Storage I n t h e s t a t e of Wyoming, t h e r e a r e c u r r e n t l y e i g h t n a t u r a l gas s t o r a g e f a c i l i t i e s which i n j e c t n a t u r a l gas i n t o r e s e r v o i r s known t o have both h o r i z o n t a l and v e r t i c a l c o n f i n i n g p r o p e r t i e s .

Known gas

caps a r e f r e q u e n t l y u t i l i z e d a s t h e s t o r a g e r e s e r v o i r s . A s w i t h t h e confined subsurface formations i n t o which s a l t water

i s i n j e c t e d f o r d i s p o s a l , t h e l i m i t s on t h e volume and r a t e of i n j e c t i o n

t o t h e s t o r a g e r e s e r v o i r a r e defined by t h e f r a c t u r i n g p r e s s u r e l i m i t s of t h e i n j e c t e d formation.

POTENTIAL ENVIRONMENTAL IMPACTS The primary environmental hazard a s s o c i a t e d w i t h petroleum r e l a t e d i n j e c t i o n o p e r a t i o n s l i e s i n t h e contamination of fresh-water a q u i f e r s and s u r f a c e w a t e r systems r e s u l t i n g from t h e l e a k a g e of i n j e c t e d b r i n e s , o r g a n i c s , and hydrocarbons. The p o s s i b l e c a u s e s of l e a k a g e and subsequent contamination from such o p e r a t i o n s a r e t h r e e - f o l d :

(1) c o r r o s i o n of i n j e c t i o n w e l l c a s i n g ;

( 2 ) f r a c t u r i n g of r e s e r v o i r and c o n f i n i n g u n i t s ; and ( 3 ) poor cementat i o n between t h e w e l l c a s i n g and t h e b o r e h o l e . A s s a l i n e w a t e r s c o n t a i n i n g d i s s o l v e d oxygen f l o w through f e r r o u s

metal w e l l casing, electrochemical r e a c t i o n s cause a gradual deteriorat i o n of t h e c a s i n g .

T h i s d e t e r i o r a t i o n i s known a s c o r r o s i o n and

r e p r e s e n t s a p o t e n t i a l l y s e r i o u s contamination hazard t o t h e fresh-water a q u i f e r s through which c a s i n g i s run.

I n j e c t i o n w e l l o p e r a t o r s have

adopted s e v e r a l c o r r o s i o n i n h i b i t i n g p r a c t i c e s t o p r e v e n t c a s i n g damage, e s p e c i a l l y where extremely c o r r o s i v e c a r b o n a t e b r i n e s a r e encountered. Among t h e p r a c t i c e s now u t i l i z e d are t h e a d d i t i o n of a n t i - c o r r o s i v e a g e n t s such as phosphates and t h e u s e of c o r r o s i o n r e s i s t a n t t u b i n g a s a b u f f e r between t h e s t e e l c a s i n g and t h e c o r r o s i v e f l u i d s (Donaldson, 1972). H y d r a u l i c f r a c t u r i n g may be d e f i n e d a s " t h e p r o c e s s of c r e a t i n g a f r a c t u r e o r f r a c t u r e system i n a porous medium by i n j e c t i n g a f l u i d under p r e s s u r e through a w e l l b o r e i n o r d e r t o overcome n a t i v e stresses and t o c a u s e m a t e r i a l f a i l u r e of t h e porous medium" (Howard and F a s t , 1970).

H y d r a u l i c f r a c t u r i n g of i n j e c t e d f o r m a t i o n s i s a p o t e n t i a l

problem i n s u b s u r f a c e i n j e c t i o n o p e r a t i o n s .

Under c e r t a i n r e s e r v o i r

c o n d i t i o n s , o p e r a t o r s may wish t o f r a c t u r e t h e r e s e r v o i r rock i n a n a t t e m p t t o produce secondary p e r m e a b i l i t y a s a means of i n c r e a s i n g t h e

r e s e r v o i r ' s a b i l i t y t o r e c e i v e and/or produce f l u i d s .

However, t h e

concern w i t h a c t i v e and proposed high-pressure i n j e c t i o n systems, whether f o r d i s p o s a l o r enhanced recovery, i s t h a t f r a c t u r i n g may exceed c a l c u l a t e d f o r e c a s t s , p e n e t r a t i n g low-permeability formations c o n f i n i n g t h e r e s e r v o i r , and allowing t h e m i g r a t i o n of p o t e n t i a l l y contaminating f l u i d s i n t o o v e r l y i n g fresh-water a q u i f e r s (Galley, 1968a). Most i n v e s t i g a t o r s a g r e e t h a t t h e t h e o r e t i c a l overburden p r e s s u r e of t h e e a r t h i s approximately equal t o 1 . 0 p s i p e r f o o t of depth (Howard and F a s t , 1970).

It i s a l s o g e n e r a l l y agreed t h a t t h e i n j e c t i o n

p r e s s u r e r e q u i r e d t o cause h o r i z o n t a l f r a c t u r i n g i n r e s e r v o i r s , regardl e s s of rock t y p e , i s approximately I p s i p e r f o o t of d e p t h , t o a depth of 3,000 f e e t (Evers, p e r s o n a l communication, 1981).

A t a depth of

8,000 f e e t , f r a c t u r i n g p r e s s u r e s d e c r e a s e t o between 0.57 and 0.85 p s i p e r f o o t of depth (Howard and F a s t , 1970).

Because of t h e i n h e r e n t

h e t e r o g e n e i t y of a c t u a l rock formations, f r a c t u r i n g i s d i f f i c u l t t o control.

Where i n j e c t i o n p r e s s u r e s approach t h e p r e s s u r e / d e p t h v a l u e s

mentioned above, i n j e c t i o n p r e s s u r e s and i n j e c t i o n volumes should be c a r e f u l l y monitored.

Sharp d e c r e a s e s i n i n j e c t i o n p r e s s u r e s and/or

sharp i n c r e a s e s i n t h e volume of f l u i d i n j e c t e d a r e i n d i c a t i v e of reservoir fracturing. I n c r e a s e s i n i n j e c t i o n p r e s s u r e may r e s u l t from t h e r e s t r i c t i o n of flow of i n j e c t e d f l u i d s from t h e w e l l b o r e t o t h e r e s e r v o i r .

The two

primary c a u s e s of f l u i d flow r e s t r i c t i o n a r e s c a l i n g and t h e " s k i n effect."

The p r e c i p i t a t i o n of m i n e r a l s from s a l i n e s o l u t i o n s on t h e

i n j e c t i o n w e l l c a s i n g and a t t h e well-formation i n t e r f a c e i s known a s scale deposition.

S c a l i n g may cause r e s t r i c t e d flow i n t o t h e i n j e c t e d

formation and n e c e s s i t a t e s u b s t a n t i a l i n c r e a s e s i n i n j e c t i o n p r e s s u r e s

and c o s t s .

S c a l i n g i s u s u a l l y i n h i b i t e d o r prevented by t h e a d d i t i o n

of phosphates t o t h e b r i n e a t t h e injection-pump manifold (Donaldson, 1972). The " s k i n e f f e c t 1 ' i s d e f i n e d a s t h e l o s s o r g a i n i n p e r m e a b i l i t y i n t h e v i c i n i t y of t h e b o r e h o l e .

The l o s s of p e r m e a b i l i t y may r e s u l t

from d r i l l i n g and i n v a s i o n , r e a c t i o n s between c l a y s and m i n e r a l s i n t h e i n j e c t e d f l u i d , chemical r e a c t i o n s between i n j e c t e d and f o r m a t i o n w a t e r s , b a c t e r i a l growth, e t c . (Warner and Lehr, 1977).

Some of t h e

extremely h i g h i n j e c t i o n p r e s s u r e s a t w a t e r f l o o d p r o j e c t s i n Wyoming may b e due t o u n d e t e c t e d " s k i n e f f e c t s " a t t h e f o r m a t i o n f a c e . P o t e n t i a l hazards associated with high i n j e c t i o n pressures a r e t h e r u p t u r i n g of w e l l c a s i n g and f r a c t u r i n g of r e s e r v o i r and c o n f i n i n g rock u n i t s . The requirement t h a t waste d i s p o s a l r e s e r v o i r s b e confined by t h i c k l a y e r s of incompetent r o c k r e d u c e s t h e danger t h a t t h e c o n f i n i n g l a y e r s w i l l b e f r a c t u r e d by e x c e s s i v e i n j e c t i o n p r e s s u r e s .

Studies

done on t h e f r a c t u r i n g of o i l r e s e r v o i r r o c k have shown t h a t " v e r t i c a l f r a c t u r e s induced i n petroleum r e s e r v o i r s do n o t p e n e t r a t e a d j a c e n t s o f t f o r m a t i o n s which have a h i g h P o i s s o n r a t i o r e l a t i v e t o t h e reserv o i r rock1' (C. W. Brown, p e r s o n a l communication, i n G a l l e y , 1968a). I n o r d e r t o a d e q u a t e l y seal o f f t h e fresh-water a q u i f e r s p e n e t r a t e d by t h e i n j e c t i o n w e l l from t h e upward m i g r a t i o n of b r i n e s , o r g a n i c s , and hydrocarbons, an e f f e c t i v e cement s h e a t h must b e set between t h e w e l l c a s i n g and t h e w a l l s of t h e b o r e h o l e .

I n a l l injection wells with

a l l t y p e s of c a s i n g s , cement should b e c i r c u l a t e d , a t l e a s t , between t h e ground s u r f a c e and 200 f e e t below t h e l a s t fresh-water a q u i f e r (Barlow, 1972).

Cement t y p e s r a n g e from common p o r t l a n d cement t o t h o s e c o n t a i n i n g admixtures such a s pozzolan, s a l t , a c c e l e r a t i o n g e l , and r e t a r d a n t s (Barlow, 1972).

A m i x t u r e of 50-50 pozzolamic cement w i t h

2 p e r c e n t g e l added i s i d e a l f o r s u r f a c e c a s i n g and t h e upper p a r t of the injection casing.

Where t h e i n j e c t e d f l u i d s a r e c o r r o s i v e , extended

epoxy r e s i n s a r e used (Barlow, 1972). A poor cementing job may a l l o w t h e m i g r a t i o n of i n j e c t e d f l u i d s i n t o v o i d s p a c e s between t h e o u t e r c a s i n g and t h e b o r e h o l e , and r e s u l t i n contamination t o a q u i f e r s a n d / o r e x t e r n a l c o r r o s i o n of t h e well casing.

Poor cement j o b s may be caused by poor c i r c u l a t i o n i n

t h e a n n u l u s , i n s u f f i c i e n t h a r d e n i n g t i m e b e f o r e d r i l l i n g i s resumed o r w e l l i s completed, o r by t h e u s e of a cement n o t chemically r e s i s t a n t t o t h e f l u i d s i n j e c t e d o r i n formations adjacent t o t h e borehole.

PHYSICAL DESCRIPTIONS OF PETROLEUM RELATED INJECTION PROJECTS The f o l l o w i n g s e c t i o n i n c l u d e s p h y s i c a l d e s c r i p t i o n s of a l l petroleum r e l a t e d i n j e c t i o n p r o j e c t s c u r r e n t l y o p e r a t i n g i n Wyoming. The p r o j e c t s i n c l u d e 265 secondary and t e r t i a r y r e c o v e r y o p e r a t i o n s , 8 n a t u r a l g a s s t o r a g e p r o j e c t s , and 90 s a l t w a t e r d i s p o s a l systems, ,

numerous f i e l d s b e i n g t h e s i t e s of more t h a n one t y p e of i n j e c t i o n project.

The n a r r a t i v e s are l i s t e d i n a l p h a b e t i c a l o r d e r by f i e l d

name. Each d e s c r i p t i o n i n c l u d e s , where p o s s i b l e , i n f o r m a t i o n on t h e f i e l d l o c a t i o n and p r o d u c t i o n h i s t o r y , g e o l o g i c s e t t i n g , h y d r o l o g i c p a r a m e t e r s , i n j e c t i o n h i s t o r y , and i n j e c t i o n w e l l d a t a .

Cumulative p r o d u c t i o n f i g u r e s g i v e n f o r each f i e l d were compiled from p r o d u c t i o n r e p o r t s s u b m i t t e d t o t h e Wyoming O i l and Gas Conservat i o n Commission through J u l y , 1980, and r e p o r t e d i n t h e Commission's Wyoming O i l and Gas S t a t i s t i c s p u b l i c a t i o n f o r t h e 1979 p r o d u c t i o n year.

Records of p r o d u c t i o n a t o l d e r f i e l d s nay be incomplete. The Petroleum R e l a t e d I n j e c t i o n W e l l I n v e n t o r y t a b l e s of Volume I1

of t h i s r e p o r t are d i v i d e d i n t o s e p a r a t e s e c t i o n s f o r each t y p e of i n j e c t i o n system ( w a t e r , g a s , steam, g a s s t o r a g e , s a l t w a t e r d i s p o s a l , and t e r t i a r y i n j e c t i o n systems). A l k a l i A n t i c l i n e F i e l d (1,492,944 b b l s o i l , 311 MCF g a s ; 1957-79) A l k a l i A n t i c l i n e Unit The completion of Unit #3 w e l l i n 1957 marked t h e d i s c o v e r y of A l k a l i A n t i c l i n e F i e l d i n Township 55 North, Range 95 West, S e c t i o n s 29, 39, and 32, approximately 6 m i l e s west of t h e town of H i m e s i n t h e n o r t h e a s t p o r t i o n of t h e Bighorn Basin. The A l k a l i A n t i c l i n e U n i t c o v e r s 590 a c r e s of f e d e r a l l y owned l a n d s i t u a t e d on a northwest plunging a n t i c l i n a l f o l d .

The a n t i c l i n e i s

c u t on t h e east s i d e by two n e a r l y north-south d i p - s l i p f a u l t s which have a combined displacement of 150 t o 200 f e e t .

Hydrocarbon accumula-

t i o n is structurally controlled. Water i n j e c t i o n i n t o t h e Tensleep Sandstone began i n A p r i l , 1979, and i s expected t o expand i n t o t h e Phosphoria Formation i n t h e n e a r future.

Water used i n t h e p r o j e c t i s o b t a i n e d from p r o d u c t i o n w e l l s

around A l k a l i A n t i c l i n e F i e l d . Casing p r e s s u r e s were checked w i t h p a c k e r s above and below t h e Phosphoria and Tensleep zones t o i n s u r e t h a t i n j e c t e d w a t e r i s confined t o those intervals.

By t h e end of 1979, 66,662 b a r r e l s (2,799,804 g a l l o n s ) of water had been i n j e c t e d i n t o t h e Tensleep r e s e r v o i r . Casing Record:

I n j e c t i o n W e l l 114, T55N-R95W-29 c a , A l k a l i A n t i c l i n e F i e l d - U n i t , T o t a l Depth = 5854 f e e t .

Casing S i z e

Depth S e t 264 ' 5865'

10-3/4" 7"

Cement 150 s a c k s 175 s a c k s

Purpose Surf a c e I nj e ct i o n

Arch F i e l d (17,672,724 b b l s o i l , 78,827,795 MCF g a s ; 1959-79) Arch U n i t The Arch o i l f i e l d was developed w i t h i n two y e a r s a f t e r t h e d i s c o v e r y of Almond Formation o i l i n 1959.

The f i e l d i s l o c a t e d approximately 35

m i l e s e a s t of Rock S p r i n g s , Wyoming, i n Township 19 North, Ranges 98 and

99 West, Sweetwater County.

The Arch Unit c o v e r s a n a r e a of 22,198.73

a c r e s and i n c l u d e s s t a t e , f e d e r a l and p r i v a t e l y owned l a n d .

The u n i t

i s o p e r a t e d by t h e Champlin Petroleum Company.

The Almond sand r e s e r v o i r c o n s i s t s of t r a n s g r e s s i v e s h o r e l i n e b a r r i e r i s l a n d s a n d s , most f a v o r a b l y developed a t t h e b a s e of t h e Upper Cretaceous Lewis S h a l e .

The s a n d s a r e c l e a n , w e l l s o r t e d , l o n g , l e n t i c u -

l a r b o d i e s t h a t i n t e r t o n g u e w i t h impermeable swamp and l a g o o n a l c o a l b e a r i n g seams. ~ 4 , 8 0 0f e e t .

The a v e r a g e d e p t h of t h e p r o d u c t i v e Almond s a n d s i s The r e s e r v o i r c o v e r s 5,965 a c r e s w i t h an a v e r a g e pay

t h i c k n e s s of 21 f e e t .

P o r o s i t y and p e r m e a b i l i t y average 21 p e r c e n t and

136 m i l l i d a r c i e s , r e s p e c t i v e l y , i n t h e Almond r e s e r v o i r . S t r u c t u r a l l y , Arch F i e l d i s l o c a t e d on t h e e a s t - c e n t r a l

f l a n k of

t h e Rock S p r i n g s u p l i f t and n e a r t h e w e s t e r n terminus of t h e Wamsutter a r c h , which s e p a r a t e s t h e Red Desert Basin t o t h e n o r t h from t h e Washakie Basin t o t h e s o u t h .

Entrapment of hydrocarbons i s provided by f a c i e s

changes from sand t o impervious s i l t , s h a l e , and c l a y t o t h e w e s t .

The

n o r t h e r n and s o u t h e r n b o u n d a r i e s t o p r o d u c t i o n a r e s t r u c t u r a l c l o s u r e s e s t a b l i s h e d by components of n o r t h and s o u t h d i p on e i t h e r f l a n k of t h e Wamsutter a r c h a x i s . A p i l o t w a t e r f l o o d p r o j e c t was undertaken i n 1964, t o enhance pro-

d u c t i o n from t h e Almond sand r e s e r v o i r .

A standard five-spot p a t t e r n

of i n j e c t i o n w e l l s was e s t a b l i s h e d , and w a t e r was s u p p l i e d by a Fox H i l l s w e l l (T18N-R99W-3da).

The p r o j e c t h a s expanded t o i n c l u d e 50

i n j e c t i o n w e l l s , 45 of which were a c t i v e a s of December, 1979.

Water

f o r t h e p r o j e c t i s now provided by two s o u r c e w e l l s i n t h e Fox H i l l s Sandstone and Lance Formation.

Water from t h e two f o r m a t i o n s was found

t o b e of s i m i l a r l y poor q u a l i t y ( h i g h TDS), and compatible w i t h t h a t of t h e Almond r e s e r v o i r . Between 1964 and 1980, a cumulative t o t a l of 28,920,125 b a r r e l s 9 (1.2146 x 1 0 g a l l o n s ) of water was i n j e c t e d i n t o t h e Almond s a n d s . Water Q u a l i t y A n a l y s i s :

Temperature: pH: Na: Ca: Mg: Fe:

Water Supply W e l l W-13-1, T19N-R99W-13 a c , Arch F i e l d , Arch U n i t , T o t a l Depth = 3680 f e e t , Lance Formation

95OF 7.2 22,284 mg/l 212 mg/l 129 mg/l 3.7 mg/l

S04: C1:

C03: HC03: CaC03: TDS:

< 5 mg/l 34,542 mg/l 48 mg/l 976 mg/l 1,060 mg/l 58,143 mg/l

Ash Creek F i e l d (5,513,696 b b l s o i l ; 1952-79) Shannon U n i t Ash Creek F i e l d i s l o c a t e d approximately 1 5 m i l e s north-northwest of S h e r i d a n , Wyoming, and e x t e n d s n o r t h a c r o s s t h e Wyoming-Montana b o r d e r . The f i e l d was d i s c o v e r e d i n 1952 w i t h t h e completion of t h e E l s i e Barry W e l l #1 i n t h e Shannon sand a t a depth of about 4,700 f e e t .

The Shannon Unit was c r e a t e d i n September, 1964, t o i n c r e a s e o i l production e f f i c i e n c y from t h e Shannon sand.

The u n i t covers 1,526.73

a c r e s of f e d e r a l , I n d i a n and p r i v a t e l y owned f e e l a n d . The producing i n t e r v a l of t h e Shannon r e s e r v o i r i s a very f i n e t o f i n e - g r a i n e d sandstone w i t h minor amounts of c h e r t , g l a u c o n i t e , c a r b o n a t e and f e l d s p a r cemented by c l a y , secondary q u a r t z and carbonate. The r e s e r v o i r c o v e r s ~ 9 8 0a c r e s w i t h an average pay t h i c k n e s s of 17 feet.

Average r e s e r v o i r p o r o s i t y and p e r m e a b i l i t y a r e 22 p e r c e n t and

275 m i l l i d a r c i e s , r e s p e c t i v e l y . S t r u c t u r a l l y , t h e f i e l d i s s i t u a t e d on a l a r g e , f a u l t e d , a n t i c l i n a l nose which plunges basinward from t h e Bighorn u p l i f t f o r about 30 m i l e s . The f a u l t e d nose h a s an approximate c l o s u r e of 400 f e e t .

Hydrocarbons

m i g r a t i n g updip a r e trapped on t h e upthrown s o u t h s i d e s of normal f a u l t s . The f a u l t s t r e n d n o r t h e a s t a t r i g h t a n g l e s t o t h e a x i s of t h e s t r u c t u r e . Dip of t h e f a u l t s i s about 45O t o t h e northwest w i t h displacement of about 250 f e e t . Water i n j e c t i o n began i n 1964, and was expanded t o a l i n e d r i v e p a t t e r n waterflood from t h e n o r t h and s o u t h s i d e s i n 1965.

Two water

supply w e l l s i n t h e Parkman sand provide a l l of t h e i n j e c t e d water. 8 Between 1964 and 1968, 7,749,925 b a r r e l s (3.255 x 10 g a l l o n s ) were

i n j e c t e d i n t o t h e Shannon r e s e r v o i r . The n o r t h e r n p o r t i o n of t h e f i e l d extends i n t o t h e Montana Crow I n d i a n R e s e r v a t i o n and c o n t a i n s f o u r i n j e c t i o n w e l l s t h a t were n o t included i n t h e Wyoming O i l and Gas Commission f i l e s . A two w e l l s a l t water d i s p o s a l system, a c t i v e s i n c e 1970, h a s

i n j e c t e d a cumulative volume of 366,233 b a r r e l s (15,381,786 g a l l o n s ) . The i n j e c t e d formation i s t h e Ash Creek sand a t a n average depth of

4,800 f e e t .

Maximum average i n j e c t i o n p r e s s u r e s a t t h e d i s p o s a l w e l l s

have been 2,000 p s i . Aspen Creek F i e l d (186,989 b b l s o i l ; 1974-79) A s a l t water d i s p o s a l system, u t i l i z i n g one i n j e c t i o n w e l l , was

s t a r t e d i n 1979 a t Aspen Creek F i e l d under t h e o p e r a t i o n of Santa Fe Energy Company.

The f i e l d i s l o c a t e d i n Township 45 North, Range 101 West, Hot

S p r i n g s County.

Produced b r i n e s a r e i n j e c t e d i n t o t h e T r i a s s i c Dinwoody

Formation and t h e Permian Phosphoria Formation.

D e t a i l e d d a t a on the w e l l

and i n j e c t i o n r e p o r t s were n o t a v a i l a b l e a t t h e time of t h i s w r i t i n g .

Barber Creek F i e l d (3,226,965 b b l s o i l , 267,966 MCF gas; 1957-79) Parkman Sand Unit The Parkman Sand Unit covers an a r e a of 3,197.16 a c r e s of f e d e r a l , s t a t e and p a t e n t e d l a n d s a t Barber Creek F i e l d .

The Parkman sand r e s e r -

v o i r c o n s i s t s of a s e r i e s of sand members, w i t h t h e Ferguson Member b e l i e v e d t o r e p r e s e n t a n e a r s h o r e , marine sand b a r d e p o s i t .

The

Ferguson sand i s t h e producing member of t h e Parkman Sandstone. Accumulation i s a r e s u l t of a sand pinchout t o t h e e a s t and an o i l water c o n t a c t t o t h e west.

Very l i t t l e water i n f l u x h a s occurred during

t h e producing l i f e of t h e r e s e r v o i r .

The o i l - w a t e r c o n t a c t i s e r r a t i c

and becomes i n c r e a s i n g l y lower t o t h e northwest.

There i s h y d r a u l i c

communication between sands, evidenced by e q u a l bottom h o l e p r e s s u r e d e c r e a s e s throughout t h e f i e l d .

A major f a u l t w i t h about 60 f e e t of displacement between t h e Dead Horse Creek-North Block Unit and t h e Barber Creek U n i t , provides a n e f f e c t i v e b a r r i e r between t h e two u n i t s .

T h e n o r t h e r n l i m i t s of t h e Barber Creek Unit a r e d e f i n e d by t h e o i l w a t e r c o n t a c t downdip and a sand pinchout updip i n t h e s o u t h h a l f of S e c t i o n 22, Township 50 North, Range 76 West. Core a n a l y s i s of t h e Ferguson sand i n d i c a t e s a n a v e r a g e p o r o s i t y of 18.3 p e r c e n t and a n a v e r a g e p e r m e a b i l i t y of 76.9 m i l l i d a r c i e s . Primary r e c o v e r y from t h e Ferguson Member was predominated by s o l u t i o n g a s d r i v e supplemented by a p a r t i a l n a t u r a l w a t e r d r i v e . i n j e c t i o n began i n 1972, w i t h seven i n j e c t i o n w e l l s .

Water

One i n j e c t o r was

added i n 1976, and a n o t h e r i n 1977.

A s of December, 1979, seven of t h e

n i n e w e l l s were a c t i v e l y i n j e c t i n g .

The cumulative t o t a l of w a t e r

8 i n j e c t e d t o t h a t t i m e was 4,756,403 b a r r e l s (1.997 x 1 0 g a l l o n s ) .

Water f o r i n j e c t i o n i s s u p p l i e d by a nearby w e l l i n F o r t Union sands. Casing Record: Casing S i z e

I n j e c t i o n W e l l # 4 4 ~ - 2 , T49N-R76W-2 dcc, Barber Creek F i e l d , Parkman Sand U n i t , T o t a l Depth = 6970 f e e t . Wt.

9-5/8" 5-1 / 2"

(#/ft)

Depth S e t

Hole S i z e

301 ' 6970'

13-3/4" 7-7 /8"

32.3 14,15.5

Cement 230 s a c k s 300 s a c k s

Basin F i e l d (906,949 b b l s o i l , 37,102 MCF g a s ; 1965-79) Minnelusa U n i t The Minnelusa U n i t of Basin F i e l d c o v e r s an a r e a of 560 a c r e s of f e d e r a l and s t a t e owned l a n d .

The Minnelusa r e s e r v o i r i s a n Upper

Pennsylvanian-Lower Permian u n i t found a t a d e p t h of about 9,650 f e e t . It c o n s i s t s of t h i c k i n t e r v a l s of s a n d s t o n e i n t e r b e d d e d w i t h a n h y d r i t e

and dolomite.

The producing sands a r e f i n e - t o medium-grained,

angular

t o round, v e r y s l i g h t l y d o l o m i t i c and moderately f r i a b l e . O i l accumulation i s c o n f i n e d t o s t r a t i g r a p h i c t r a p s above t h e o i l -

w a t e r c o n t a c t , which forms t h e w e s t e r n l i m i t of o i l p r o d u c t i o n . paleo-erosion

A

channel and s h a l e f i l l form t h e n o r t h e r n l i m i t of t h e

productive sandstone a t t h e u n i t .

The e a s t e r n l i m i t i s c l o s e l y a l i g n e d

w i t h a f a c i e s change from porous, o i l p r o d u c t i v e s a n d s t o n e t o t i g h t , impermeable dolomite.

The s o u t h e r n boundary i s i n t e r p r e t e d a s a paleo-

e r o s i o n channel d i s c o n t i n u i t y . The o r i g i n a l mechanism of o i l p r o d u c t i o n from t h e Minnelusa r e s e r v o i r was l i q u i d and r o c k expansion. A t w e l l number 62-13019

(T47N-R70W-16

da) t h e a v e r a g e p o r o s i t y and

h o r i z o n t a l p e r m e a b i l i t y a r e 14.7 p e r c e n t and 61.8 m i l l i d a r c i e s , respect i v e l y , f o r a 24-foot i n t e r v a l of pay zone s a n d s i n t h e Minnelusa Formation. I n j e c t e d w a t e r i s s u p p l i e d by a s h a l l o w w e l l (2,600 f e e t ) i n t h e Fox H i l l s s a n d s and by produced w a t e r from t h e Minnelusa Formation. I n j e c t i o n began i n 1966, and cumulative i n j e c t i o n a s of December, 8 1979, was 2,445,393 b a r r e l s (1.0271 x 1 0 g a l l o n s ) of w a t e r .

Both

i n j e c t i o n w e l l s a r e p r e s e n t l y shut-in. Casing Record:

I n j e c t i o n Well # I , T47N-R70W-16 c a a , Basin F i e l d , Minnelusa U n i t , T o t a l Depth = 9765 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5 / 8"

24

5-1/2"

17,15.5

Depth S e t

Hole S i z e

Cement

347 '

12-1/4"

275 s a c k s

9765'

7-7/8"

250 s a c k s

Basin F i e l d Northwest (1,099,329 b b l s o i l , 175 MCF g a s ; 1965-79) Piney Ranch Minnelusa U n i t Basin F i e l d Northwest i s l o c a t e d i n Township 47 North, Range 70 West, Campbell County.

Water i n j e c t i o n began i n t h e Basin Northwest

Piney Ranch Minnelusa U n i t i n 1970.

By December, 1979, t h e c u m u l a t i v e

7 t o t a l of i n j e c t e d w a t e r was 1,926,881 b a r r e l s (8.0929 x 1 0 g a l l o n s ) w i t h o n l y one of t h e t h r e e i n j e c t i o n w e l l s remaining a c t i v e .

The water supply f o r t h e Piney Ranch Minnelusa Unit waterflood p r o j e c t was, u n t i l 1977, withdrawn from t h e F o r t Union Formation. I n 1977, Union Texas Petroleum began supplementing t h e f r e s h water

from t h e F o r t Union w i t h produced water from t h e Minnelusa Formation and, l a t e r t h a t y e a r , converted t o t h e i n j e c t i o n of produced water only. Water q u a l i t y a n a l y s e s from produced Minnelusa water i n d i c a t e d very h i g h c o n c e n t r a t i o n s of sodium p l u s potassium (42,202 mgll) and c h l o r i d e (65,000 m g l l ) .

The c o n c e n t r a t i o n of c a l c u l a t e d t o t a l d i s s o l v e d

s o l i d s was 112,613 mg/l. The average p o r o s i t y and p e r m e a b i l i t y of t h e Minnelusa sands a t w e l l #5 a r e 12.7 p e r c e n t and 48.4 m i l l i d a r c i e s , r e s p e c t i v e l y , a t depths between 9,911 and 9,981 f e e t . Casing Record:

I n j e c t i o n Well #3, T47N-R70W-5 daa, Basin F i e l d NW, Piney Ranch Minnelusa U n i t , T o t a l Depth = 9812 feet.

Casing S i z e

Wt.

(#/ft)

Depth S e t

Hole S i z e

Cement

8-518"

24

381'

12-114"

215 sacks

5-112"

17

9808'

7-718"

400 sacks

Water Q u a l i t y Analysis:

Parameter Na

+K Ca Mg S04 C1 HC04 PH

(Water sample from Minnelusa Formation a t w e l l # 2 , Basin F i e l d Northwest, Piney Ranch Minnelusa U n i t , T47N-R70W-Section 5 NE% S E ~ , Depth of Well = 9812 f e e t , P e r f o r a t i o n s 9708-9728 f e e t )

Concentration (mgll)

Total Solids

42,202 866 541 3,228 65,500 562 6.9

By evaporation af ter i g n i t i o n calculated

Concentration (rngll) 114,588 111,136 112,612

Beaver Creek F i e l d (48,200,841 b b l s o i l , 471,605,353 MCF gas; 1938-79) Beaver Creek F i e l d i s l o c a t e d i n Township 33 North, Range 96 West, S e c t i o n s 2, 3 , 9, 1 0 , 11, 15, and 16 i n c e n t r a l Fremont County. The f i e l d was discovered i n 1938, when a n a t u r a l gas w e l l was completed i n t h e Dakota sand a t a depth of 8,230 f e e t .

Subsequent o i l d i s c o v e r i e s

were made i n t h e Mesaverde (second Cody sand) Formation, Tensleep Sandstone and Madison Limestone.

U n i t i z a t i o n of Beaver Creek F i e l d ,

which divided i t i n t o t h e Second Cody and Madison u n i t s , was approved i n 1937.

I n j e c t i o n water i s provided by t h e Meeteetse and Wind River

formations and by production w e l l s i n t h e Madison Limestone and second Cody sand. S t r u c t u r a l l y , Beaver Creek F i e l d i s s i t u a t e d an a g e n t l y folded anticline.

Madison Unit The Madison Unit of Beaver Creek F i e l d covers 1,230 a c r e s of s t a t e and f e d e r a l land.

The Madison r e s e r v o i r has an average g r o s s

pay t h i c k n e s s of 150 f e e t and covers 1,260 a c r e s .

A l l of t h e pay

zones i n t h e Madison Limestone of Beaver Creek F i e l d a r e a t depths g r e a t e r than 11,000 f e e t , making t h i s t h e deepest water i n j e c t i o n p r o j e c t i n t h e Rocky Mountain region.

Average p e r m e a b i l i t y and

p o r o s i t y f o r t h e Madison Limestone a r e 8 m i l l i d a r c i e s and 18 p e r c e n t , respectively. The water i n j e c t i o n p r o j e c t i n t h e Madison Unit began i n 1959, u t i l i z i n g water obtained from s e v e r a l w e l l s completed i n t h e a l l u v i a l g r a v e l of t h e Wind River Formation a t a dpeth of about 100 f e e t . The p r o j e c t was l a t e r expanded t o i n c l u d e s i x i n j e c t i o n w e l l s and 19

production w e l l s .

F i v e of t h e i n j e c t i o n w e l l s a r e d u a l l y completed

t o permit water i n j e c t i o n i n t h e lower zone below a packer and o i l production from t h e upper zone above t h e packer. 8 Cumulative i n j e c t i o n a s of December, 1979, was 1.1277 x 1 0 9 b a r r e l s (4.7363 x 10 g a l l o n s ) of water. Second Cody Unit The a r e a covered by t h e Second Cody Unit of Beaver Creek F i e l d i n c l u d e s 760 a c r e s of f e d e r a l l y owned land and 770 a c r e s of s t a t e owned land.

The second Cody r e s e r v o i r covers 977 a c r e s w i t h an average

pay zone t h i c k n e s s of 24 f e e t . A p i l o t waterflood of t h e second Cody (Mesaverde) r e s e r v o i r

began i n 1958, u s i n g water from t h e Meeteetse sand which i s found a t depths between 2,122 and 2,210 f e e t .

The p i l o t p r o j e c t was expanded

t o a p e r i p h e r a l waterflood of f i v e i n j e c t i o n w e l l s and n i n e producing w e l l s i n 1959.

Water from t h e Meeteetse Formation was analyzed a s

hard and s a l t y , r e n d e r i n g i t u n d e s i r a b l e f o r domestic o r a g r i c u l t u r a l use.

The most r e c e n t cumulative i n j e c t i o n s t a t u s t i c s (December, 1979)

9 i n d i c a t e t h a t 27,078,181 b a r r e l s (1.1373 x 10 g a l l o n s ) of water have been i n j e c t e d s i n c e t h e p r o j e c t began.

Big Muddy F i e l d (52,498,213 b b l s o i l , 38,762 MCF gas; 1916-79) The Big Muddy o i l f i e l d , l o c a t e d near Glenrock, Wyoming (Townships 33 and 34 North, Range 76 West), was i n i t i a l l y developed following t h e completion of a w e l l i n t h e Shannon sand i n 1916.

O i l was subsequently

discovered i n t h e Wall Creek sand between 3,147 and 3,217 f e e t i n 1917, i n t h e Dakota sand i n 1922, and i n t h e Lakota sand between 4,353 and 4,364 f e e t i n 1931.

I n March, 1953, a p i l o t water i n j e c t i o n p r o j e c t began i n t h e Second Wall Creek Sand Unit.

The Second Wall Creek p r o j e c t and

another waterflood p r o j e c t i n t h e Dakota Unit a r e c u r r e n t l y operated by C o n t i n e n t a l O i l Company.

J. G. Dyer Company now o p e r a t e s water

i n j e c t i o n p r o j e c t s i n t h e South Block Wall Creek and Dakota u n i t s . A f i f t h waterflood p r o j e c t i n t h e East Unit Dakota sand i s operated

by A t l a n t i c R i c h f i e l d Company. I n j e c t i o n water f o r a l l of t h e p r o j e c t s i s obtained from t h e Wall Creek, Lakota, and Tensleep sandstones, t h e Madison Limestone, t h e Dakota sand, and two shallow w e l l s near t h e North P l a t t e River. The Department of Energy and C o n t i n e n t a l O i l Company a r e c u r r e n t l y p a r t i c i p a t i n g i n a r e s e r v o i r study a t Big Muddy F i e l d .

The

purpose of t h e s t u d y , i n i t i a t e d i n January, 1978, i s t o demonstrate t h e commercial f e a s i b i l i t y of a low t e n s i o n i n j e c t i o n process i n a t y p i c a l Rocky Mountain r e s e r v o i r w i t h low m a t r i x p e r m e a b i l i t y and low s a l i n i t y , and which f r a c t u r e s a t bottom h o l e i n j e c t i o n p r e s s u r e s n e a r , and o f t e n l e s s t h a n , h y d r o s t a t i c p r e s s u r e . Wall Creek Unit The Wall Creek sand r e s e r v o i r covers an a r e a of 3,560 a c r e s a t Big Muddy F i e l d .

The average t h i c k n e s s of t h e pay zone i s 38 f e e t .

Average p o r o s i t y and p e r m e a b i l i t y of t h e r e s e r v o i r sands a r e 20 percent and 20-100 m i l l i d a r c i e s , r e s p e c t i v e l y .

The i n i t i a l producing mechanisms

of t h e r e s e r v o i r were s o l u t i o n gas d r i v e and a weak n a t u r a l water drive.

Water encroachment around t h e edges of t h e r e s e r v o i r had been

only one m i l e between 1933 and 1968.

A s of 1968, t h e r a t i o of water i n j e c t e d t o secondary o i l

recovered was 8 : l .

Water used f o r i n j e c t i o n i s obtained from two

w e l l s i n t h e Lakota Sandstone and one w e l l i n t h e Sundance Formation. Produced water from Wall Creek and Dakota sand o i l w e l l s i s a l s o used. The cumulative volume of water i n j e c t e d between 1953 and December, 1979, was 65,440,526 b a r r e l s (2.7485 x LO 9 g a l l o n s ) .

Only s i x

i n j e c t i o n w e l l s a r e c u r r e n t l y a c t i v e i n t h e Wall Creek Unit.

Casing Record:

I n j e c t i o n Well 1/79, T33N-R76W-9 ad, Big Muddy F i e l d , Wall Creek U n i t , T o t a l Depth = 3209 f e e t .

Casing Size

Depth S e t

Hole S i z e

8-5 18"

264'

12-1/4"

24

4-11 2"

3209'

7-718"

10.5

Wt.

(#/ft)

Purpose

Cement

Surf a c e

190 sacks (Class "G")

Injection

100 sacks (Class "G")

South Wall Creek Unit O i l was discovered i n t h e Wall Creek sand of South Big Muddy F i e l d

i n 1917.

The a r e a of s t a t e owned land was u n i t i z e d i n 1963, and water

i n j e c t i o n began i n 1964.

The productive a r e a and average pay t h i c k n e s s

of t h e Wall Creek r e s e r v o i r a r e 507 a c r e s and 20 f e e t , r e s p e c t i v e l y . The Wall Creek Sandstone c o n t a i n s two porous sand zones ( f i r s t and second Wall Creek sands) which a r e being i n j e c t e d w i t h f r e s h water from t h e Tensleep Sandstone and Madison Limestone. The f i r s t Wall Creek sand h a s a g r o s s t h i c k n e s s of 15 f e e t . The second Wall Creek sand h a s a g r o s s t h i c k n e s s of 60 f e e t and an average p e r m e a b i l i t y of 70 m i l l i d a r c i e s .

Four of t h e s i x i n j e c t i o n

w e l l s a r e c u r r e n t l y a c t i v e and t h e cumulative volume of water i n j e c t e d 8 a s of December, 1979, was 13,364,166 b a r r e l s (5.6129 x 10 g a l l o n s ) .

Casing Record:

I n j e c t i o n W e l l #3, T33N-R76W-16 a a , South Wall Creek U n i t , T o t a l Depth = 3358 f e e t .

Casing S i z e

Wt.

10-3 / 4"

(#/ft)

Perf o r a t i o n s

-

32.75

3272-3275 3281-3292 3294-3300

Purp-ose Surface Lnj e c t i o n

Dakota Unit The Dakota r e s e r v o i r covers an a r e a of 1,941 a c r e s w i t h i n t h e boundaries of t h e s t a t e , f e d e r a l and p r i v a t e l y owned land of t h e Dakota Unit.

The average t h i c k n e s s of t h e Dakota sand pay horizon

is 10 f e e t . The producing mechanism of t h e Dakota r e s e r v o i r was s o l u t i o n gas d r i v e u n t i l 1958, when a 5-spot p a t t e r n p i l o t waterflood was i n i t i a t e d on t h e c r e s t of t h e Big Muddy s t r u c t u r e t o enhance production.

The p r o j e c t was l a t e r expanded t o a f u l l s c a l e waterflood

w i t h 32 i n j e c t i o n w e l l s .

S i t e s f o r t h e new w e l l s were s e l e c t e d based

on r e c o r d s of f a u l t i n g w i t h i n t h e r e s e r v o i r . A s of December, 1979, 19 of t h e w e l l s were s t i l l a c t i v e l y i n j e c t 9 i n t and 36,289,349 b a r r e l s (1.5242 x 10 g a l l o n s ) of water had been i n j e c t e d s i n c e t h e p r o j e c t began.

Sources f o r t h e f r e s h and

produced water used i n t h e Dakota i n j e c t i o n p r o j e c t a r e t h e Sundance Formation, Wall Creek and Lakota sandstones, and t h e Dakota sand.

Casing Record:

Casing Size

I n j e c t i o n Well S t a t e l a n d 10 #25, T33N-R76W-10 abc, Big Muddy F i e l d , Dakota Unit, T o t a l Depth = 4579 f e e t .

Depth S e t

Hole S i z e

Wt.

(#/ft)

9-5/8"

243 '

12-1/4"

36

5-1/2"

4579'

8-3/4"

15.5

Purpose

Cement

Surface

200 sacks (Class "G")

Injection

460 sacks light-weight and 50 sacks (Class "G")

Dakota South Sand Unit The Dakota Sand Unit r e s e r v o i r i n South Big Muddy F i e l d u n d e r l i e s a s m a l l dome s o u t h of t h e main Dakota producing a r e a .

The

r e s e r v o i r covers 200 a c r e s and has an average pay horizon t h i c k n e s s of 5 feet. The u n i t i s operated by J. G. Dyer Company and i s owned by p r i v a t e landowners and t h e S t a t e of Wyoming.

The a r e a was u n i t i z e d i n 1961,

and water i n j e c t i o n i n t o t h e Dakota sand began a s h o r t time l a t e r . The waterflood p r o j e c t has one a c t i v e i n j e c t i o n w e l l and two w e l l s t h a t have been temporarily s h u t - i n .

Between 1961 and 1980, 1,458,137

7 b a r r e l s (6.1242 x 10 g a l l o n s ) of water were i n j e c t e d i n t o t h e Dakota reservoir.

Casing Record :

Casing S i z e

I n j e c t i o n Well S t a t e #0-20200 2A, T33N-R76W-21 bc, South Big Muddy F i e l d , Dakota U n i t , T o t a l Depth = 4845 f e e t . Wt.

(#/ft)

Amount

8-5/8"

32

113 '

4-1/2"

9.5

4845'

Guide

Make

Purpose Surface

5-55

R- 2

Injection

East Unit The East Unit of Big Muddy F i e l d i s l o c a t e d i n S e c t i o n s 1, 2 and 3 of Township 33 North, Range 76 West and S e c t i o n s 34 and 35 of Towns h i p 34 North, Range 76 West.

The u n i t is operated by A t l a n t i c Rich-

f i e l d Company. Water i n j e c t i o n began i n 1961, following u n i t i z a t i o n of 520 a c r e s of t h e Dakota r e s e r v o i r i n t h e n o r t h e a s t corner of Big Muddy F i e l d . The average t h i c k n e s s of t h e pay zone i s 11 f e e t . 8 A s of December, 1979, 12,550,348 b a r r e l s (5.2711 x 10 g a l l o n s )

of water had been i n j e c t e d through 12 w e l l s , only two of which a r e still active.

I n 1968, t h e amount of produced o i l a t t r i b u t e d t o t h e

waterflood p r o j e c t was %630,000 b a r r e l s .

Big Piney F i e l d (1,698,624 b b l s o i l , 37,332,843 MCF gas; 1964-79) I n t h e middle of w i n t e r , 1938, t h e discovery w e l l a t Big Piney F i e l d "blew in" w i t h n a t u r a l gas from t h e Almy gas sands which a r e found a t a depth of approximately 1,000 f e e t . water from sands o v e r l y i n g t h e gas zone.

Accompanying t h e gas was

I n t h e subzero temperatures

a t t h e s u r f a c e t h e water draped t h e d r i l l i n g d e r r i c k w i t h s h e e t s of ice.

The w e l l had been s t a n d i n g i d l e f o r t h r e e weeks a t a t o t a l depth

of 1,695 f e e t when t h e blowout occurred. O i l was i n i t i a l l y produced a t Big Piney from sands i n t h e Wasatch

Formation i n 1955.

I n J u l y , 1957, o i l was discovered i n t h e "P" sand

r e s e r v o i r of t h e Almy sand.

Other o i l d i s c o v e r i e s were made i n

l e n t i c u l a r sands of t h e Mesaverde and Wasatch formations.

The Big Piney

a n t i c l i n e i s l o c a t e d i n Townships 28 and 29 North, Ranges 112 and 113 West, S u b l e t t e County. Sand and Long I s l a n d

Big Piney F i e l d i n c l u d e s t h e Mesaverde, "P" "SC" u n i t s .

The T i p Top Hogsback S a l t w a t e r d i s p o s a l system a t Big P i n e y F i e l d s t a r t e d i n 1965 and was expanded t o a two w e l l system i n 1971. 8 Between 1965 and December, 1979, 19,903,881 b a r r e l s (8.3596 x 1 0

g a l l o n s ) of produced b r i n e were i n j e c t e d i n t o t h e F o r t Union Formation a t a n a v e r a g e p r e s s u r e of 1,300 p s i .

Both w e l l s a r e a c t i v e l y i n j e c t i n g

a t the present t i m e .

Mesaverde U n i t The Big P i n e y Mesaverde r e s e r v o i r l i e s n e a r t h e s o u t h e a s t end of t h e Big P i n e y a n t i c l i n e on t h e west edge of t h e Green R i v e r Basin.

The

p r o d u c t i v e i n t e r v a l of t h e r e s e r v o i r i n c l u d e s a T e r t i a r y b a s a l conglome r a t e f o r m a t i o n and t h e upper and lower p o r t i o n s of t h e Cretaceous Mesaverde Formation.

The conglomerate l i e s unconformably above t h e

upper Mesaverde and $he upper and lower Mesaverde are s e p a r a t e d by a s h a l e bed of v a r i a b l e t h i c k n e s s .

The T e r t i a r y conglomerate i s a q u a r t z

p e b b l e conglomerate w i t h a sand and c l a y m a t r i x .

Average p o r o s i t y and

p e r m e a b i l i t y of t h e conglomerate a r e 11.9 p e r c e n t and 58.6 m i l l i d a r c i e s , respectively.

However, t h e c o r e used f o r t h e a n a l y s i s was incomplete

and c o n s i d e r e d n o n r e p r e s e n t a t i v e of t h e conglomerate pay zone. The Mesaverde s a n d s are f i n e - t o medium-grained s i l i c e o u s sands t o n e s w i t h minor amounts of a r g i l l a c e o u s and carbonaceous m a t e r i a l . The upper sand h a s a m a t r i x p o r o s i t y of 1 8 p e r c e n t and h o r i z o n t a l and v e r t i c a l p e r m e a b i l i t i e s of 7.8 and 8.2 m i l l i d a r c i e s , r e s p e c t i v e l y . The lower Mesaverde zone h a s a p o r o s i t y of 14.6 p e r c e n t and h o r i z o n t a l and v e r t i c a l p e r m e a b i l i t i e s of 4.6 and 4.3 m i l l i d a r c i e s , r e s p e c t i v e l y . The Mesaverde r e s e r v o i r c o v e r s a broad a r e a of l o c a l l y u n r e s t r i c t e d and u n f a u l t e d rock.

P r o d u c t i o n l i m i t s a r e d e f i n e d by a n o i l - w a t e r

c o n t a c t t o t h e e a s t and water encroachment t o t h e s o u t h .

The western

production boundary is a s t r u c t u r a l high which caused entrapment of hydrocarbons by e i t h e r a northwest-southeast

t r e n d i n g high r e l i e f

f o l d , a major f a u l t of s i m i l a r o r i e n t a t i o n o r a r e s e r v o i r pinchout toward t h e a x i s of t h e s t r u c t u r e . The Mesaverde Unit c o n s i s t s of 2,949 a c r e s of s t a t e and f e d e r a l land and i s c u r r e n t l y operated by Gulf O i l Company.

Secondary recovery

of o i l by water i n j e c t i o n began I n 1 9 6 8 , and u t i l i z e s water obtained from o i l production w e l l s i n t h e Mesaverde and from water supply w e l l s completed i n t h e Almy sand a t a depth of approximately 1,000 f e e t . 6 It was estimated t h a t 6.8 x 10 b a r r e l s of a d d i t i o n a l o i l would b e recovered a s a r e s u l t of t h e waterflood p r o j e c t . A s of December, 1979, seven of t h e p r o j e c t ' s e i g h t i n j e c t i o n w e l l s

were a c t i v e l y o p e r a t i n g .

T o t a l volume of water i n j e c t e d t o t h a t p o i n t

was 28,505,697 b a r r e l s (1.1972 x LO

Casing Record: Casing S i z e

9

gallons).

I n j e c t i o n Well #15-7, T29N-R113W-36 bbd, Big Piney F i e l d , Mesaverde U n i t , T o t a l Depth = 3600 f e e t . Wt.

Amount

(#/ft)

Perforations

8-5 /8"

24

254 '

-

5-1/2"

14

3448 '

3320-3370'

Purpose Surf ace Injection

"P" Sand Unit I n J u l y , 1957, o i l was discovered i n t h e "PI' sand r e s e r v o i r of t h e Almy sand i n Big Piney F i e l d .

The "P" sand r e s e r v o i r covers an a r e a

of 878 a c r e s w i t h a maximum t h i c k n e s s of 28 f e e t and an average pay t h i c k n e s s of 16.2 f e e t .

The "P" sand i s a l e n t i c u l a r Paleocene sand

which v a r i e s i n t h i c k n e s s from 0 t o 100 f e e t and h a s a d i p of 3 degrees t o the east.

The average depth t o t h e top of t h e sand i s 2,675 f e e t .

The r e s e r v o i r c o n s i s t s of a primary gas cap p a r t i a l l y overlying an o i l zone which i s u n d e r l a i n by water. Hydrocarbon accumulation i n t h e "P" sand i s a r e s u l t of s t r a t i g r a p h i c entrapment a s s o c i a t e d w i t h i d e a l a n t i c l i n a l s t r u c t u r a l c o n d i t i o n s . The sand pinches out t o t h e n o r t h and west, has an oil-water t h e e a s t , and meets a b a r r i e r f a u l t t o t h e s o u t h .

contact t o

Performance d a t a

i n d i c a t e t h a t t h e r e s e r v o i r i n i t i a l l y produced by a s o l u t i o n gas d r i v e , s l i g h t l y augmented by g a s cap expansion. The "P" Sand Unit was u n i t i z e d i n November, 1962, by Pan American Petroleum Corporation and covers 2,212.57 a c r e s of f e d e r a l and s t a t e land.

Waterflooding began i n August, 1963, w i t h water obtained from a

shallow w e l l i n t h e Green River Formation.

Water was i n j e c t e d i n t o

t h r e e w e l l s near t h e g a s - o i l c o n t a c t t o prevent o i l movement i n t o t h e 11

dry" g a s r e s e r v o i r .

Once r e s e r v o i r p r e s s u r e was i n c r e a s e d , production

through t h e g a s w e l l s was resumed.

Gas i n j e c t i o n i n t o t h e g a s cap

through one w e l l began i n December, 1962.

A s of December, 1979,

8 16,812,498 b a r r e l s (7.0612 x 10 g a l l o n s ) of water and 6,373,254 MCF of n a t u r a l gas had been i n j e c t e d i n t o t h e "P" sand r e s e r v o i r .

Five wells

were a c t i v e l y i n j e c t i n g a t t h a t t i m e . Casing Record:

Casing S i z e

I n j e c t i o n Well #9, T29N-R113W-36 a a ( a c ) , Big Piney F i e l d , "P" Sand U n i t , T o t a l Depth = 3670 f e e t . Wt.

(#/ft)

Amount

8-5/8"

24

256'

5-1/2"

14

3347 '

Perf o r a t i o n s

Purpose Surface

2690-3288'

Injection

Long I s l a n d Unit The Long I s l a n d "SC" Sand Unit of Big Piney F i e l d i s l o c a t e d i n S e c t i o n s 18, 19, 20, and 29 of Township 30 North, Range 112 West,

S u b l e t t e County.

The u n i t c o v e r s 680 a c r e s of f e d e r a l l y owned

land. The "SC" sand r e s e r v o i r i s p a r t of t h e Paleocene Almy sand found a t a d e p t h of about 1 , 7 0 0 f e e t i n t h e Big Piney a r e a .

The

Almy sand i s a m u l t i c o l o r e d s h a l e and s i l t s t o n e w i t h a few t h i c k sandstones interbedded.

The s a n d s t o n e s are gray-white t o s a l t and

pepper, v e r y f i n e - t o coarse-grained and w e l l c o n s o l i d a t e d . S t r u c t u r e i n t h e area i s a n o r t h e a s t d i p p i n g monocline of one t o two d e g r e e s i n c l i n a t i o n w i t h only minor v a r i a t i o n s .

The p r o d u c t i o n

b o u n d a r i e s are d e f i n e d by a n updip pinchout of t h e "SC" sand on t h e

w e s t and a n o i l - w a t e r c o n t a c t on t h e east. Waterflooding of t h e "SC" r e s e r v o i r was i n i t i a t e d i n 1969, u s i n g w a t e r from o u t s i d e t h e f i e l d w i t h a polymer added.

A s of December,

1979, t h e r e were s i x a c t i v e i n j e c t i o n w e l l s i n t h i s u n i t o p e r a t e d by Belco Petroleum C o r p o r a t i o n . f o r 1976 only.

Cumulative i n j e c t i o n d a t a were a v a i l a b l e

During 1976, 716,548 b a r r e l s (30,095,016 g a l l o n s ) of

water were i n j e c t e d i n t o t h e "SC" r e s e r v o i r .

Casing r e c o r d s f o r

i n j e c t i o n w e l l s were u n a v a i l a b l e a t t h e t i m e of t h i s w r i t i n g .

B i l l y Creek F i e l d (6,471,217 MCF g a s i n s t o r a g e ; 1923-79) B i l l y Creek F i e l d , l o c a t e d i n Township 48 N.orth, Bange 82 West, Johnson County, h a s been t h e s i t e of a g a s s t o r a g e p r o j e c t o p e r a t e d by Montana-Dakota U t i l i t i e s s i n c e 1941.

The F r o n t i e r Formation i s t h e

r e s e r v o i r b e i n g used t o s t o r e t h e 6,471,217 MCF of n a t u r a l g a s . i n j e c t i o n w e l l s have been u t i l i z e d d u r i n g t h e p r o j e c t .

Three

Two of t h e w e l l s

remain on a c t i v e s t a t u s a c c o r d i n g t o s t a t i s t i c s compiled i n J a n u a r y , 1980, by t h e O i l and Gas Commission.

B i r c h Creek F i e l d (87,488,060 b b l s o i l , 111,998,816 MCF g a s ; 1957-79) Almy ( B i r c h Creek) U n i t The Almy U n i t of B i r c h Creek F i e l d i s l o c a t e d i n t h e e a s t h a l f of Township 27 North, Range 113 West, S u b l e t t e County.

The u n i t was

approved i n J a n u a r y , 1957, and i s s t i l l o p e r a t e d by Chevron O i l Company. Gas was d i s c o v e r e d i n t h e Bear River Formation i n A p r i l , 1957, and

subsequent o i l d i s c o v e r i e s were made i n t h e Alny ( B i r c h Creek) and Mesaverde r e s e r v o i r s . The Almy sand r e s e r v o i r c o v e r s a n a r e a of 600 a c r e s and h a s an a v e r a g e pay zone t h i c k n e s s of 3 1 f e e t .

The o r i g i n a l producing energy

i n t h e r e s e r v o i r was provided by g a s expansion. I n December, 1963, w a t e r i n j e c t i o n began through a l i n e of t h r e e w e l l s l o c a t e d between t h e Almy and Mesaverde u n i t s .

The purpose of

t h e s e i n j e c t o r s was t o p r e v e n t t h e m i g r a t i o n of o i l between t h e two reservoirs.

I n j e c t i o n w a t e r f o r t h e Almy r e s e r v o i r w a t e r f l o o d i s

o b t a i n e d from w e l l s i n t h e Wasatch Formation and from p r o d u c t i o n w e l l s i n t h e Almy sand. 9 A s of December, 1979, 25,229,777 b a r r e l s (1.0597 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d through 4 i n j e c t i o n w e l l s s i n c e t h e waterf l o o d p r o j e c t began.

Only one of t h e w e l l s i s c u r r e n t l y a c t i v e .

A s a l t w a t e r d i s p o s a l system was s t a r t e d i n 1977, t o i n j e c t w a t e r

from Birch Creek F i e l d producing w e l l s i n t o t h e Almy "D-2"

sand.

The a v e r a g e i n j e c t i o n p r e s s u r e a t t h e s i n g l e d i s p o s a l w e l l i s 1,300 psi.

A s of J a n u a r y , 1979, 63,768 b a r r e l s (2,678,256 g a l l o n s ) of b r i n e

had been d i s p o s e d of through w e l l #46DW.

Mesaverde Unit The Mesaverde Unit of Birch Creek F i e l d i s l o c a t e d j u s t northwest of t h e Almy Unit i n S e c t i o n s 15 and 22 of Township 27 North, Range 113 West.

The u n i t a r e a i n c l u d e s 540 a c r e s of f e d e r a l l y owned l a n d . The Mesaverde r e s e r v o i r is a gray t o l i g h t gray, s a l t and pepper,

c a l c a r e o u s , s i l t y , s l i g h t l y a r g i l l a c e o u s , f i n e - t o v e r y fine-grained, g e n e r a l l y w e l l s o r t e d , subangular t o subrounded, moderately f r i a b l e sandstone.

P o r o s i t y averages 1 8 percent i n t h e Mesaverde Formation and

t h e average p e r m e a b i l i t y i s 10 m i l l i d a r c i e s .

By t h e end of December,

1979, both i n j e c t i o n w e l l s completed i n t h e Mesaverde r e s e r v o i r were temporarily shut-in.

Cumulative i n j e c t i o n through t h o s e w e l l s has

8 t o t a l e d 3,002,258 b a r r e l s (1.2609 x 10 g a l l o n s ) of water.

Casing

r e c o r d s f o r t h e two i n j e c t i o n w e l l s were u n a v a i l a b l e a t t h e time of t h i s writing. South Bishop Ranch F i e l d (1,607,901 b b l s o i l , 20,717 MCF gas; 1968-79) South Bishop Ranch Minnelusa Unit The South Bishop Ranch Unit covers an a r e a of 640 a c r e s of f e d e r a l l y and s t a t e owned land i n t h e s o u t h e a s t corner of Township 48 North, Range 70 West, Campbell County.

O i l production began i n 1964, w i t h t h e

primary mechanism of production r e s u l t i n g from t h e expansion of compressed reservoir fluids. The Minnelusa A r e s e r v o i r i s found a t a depth of approximately 9,250 f e e t a t t h e South Bishop Ranch Unit.

The average p o r o s i t y and

p e r m e a b i l i t y of t h e r e s e r v o i r sands a r e 15.1 percent and 100 m i l l i d a r c i e s , respectively.

The i n j e c t i o n of water, produced from t h e Minnelusa Formation, was i n i t i a t e d i n 1970 through two w e l l s . added.

I n 1973, a t h i r d i n j e c t o r was

Because t h i s Minnelusa waterflood was a t y p i c a l of t h e m a j o r i t y

of Minnelusa waterflood p r o j e c t s i n t h e Powder River Basin, t h e S t a t e O i l and Gas Commissioner of Wyoming c l o s e l y monitored i n j e c t i o n and

production r e c o r d s during 1976 and 1977.

There was some doubt a s t o

whether o r n o t t h e i n t e r v a l i n t o which water was being i n j e c t e d was h y d r a u l i c a l l y connected w i t h any of t h e producing w e l l s i n t h e South Bishop Ranch Unit.

The Commissioner pointed t o " t h e f a c t t h a t t h r e e

y e a r s of i n j e c t i o n has not y i e l d e d a conclusive production response a t wells within the unit.

...

We a r e concerned w i t h t h e i n j e c t i o n of

approximately one m i l l i o n b a r r e l s of water i n t o an a q u i f e r of unknown e x t e n t , t h e r e s u l t of which i s a l s o unknown.

. . . response t o w a t e r

i n j e c t i o n ( i n s e v e r a l Minnelusa r e s e r v o i r s , a l l l o c a t e d i n t h e Powder River Basin of Wyoming) i s , without exception, immediate and t y p i c a l l y dramatic" ( O i l and Gas Commission f i l e s ) .

Another one m i l l i o n b a r r e l s

have been i n j e c t e d s i n c e 1977, and no "dramatic" responses i n production w e l l s have y e t occurred.

Only one of t h e t h r e e i n j e c t i n g w e l l s

remained a c t i v e a s of December, 1978.

It i s l o c a t e d on t h e approximate

oil-water c o n t a c t of t h e r e s e r v o i r , T48N-R70W-35

aa.

The Commission

has n o t pursued t h e i n v e s t i g a t i o n .

Casing Record: Casing S i z e

I n j e c t i o n Well #1, T48N-R70W-35 aab, South Bishop Ranch F i e l d , Minnelusa U n i t , T o t a l Depth = 9600 f e e t . Wt.

(#/ft)

Depth S e t

Hole S i z e

Cement

8-5/8"

24

307

12-1/4"

240 sacks

5-1/2"

15.5, 1 7

9600

7-718"

300 sacks

4-1/2"

13.5, 11.6

9600

7-7 /8"

300 sacks

Bison Basin F i e l d (1,958,698 b b l s o i l , 554,495 MCF g a s ; 1929-79) F r o n t i e r Unit Bison Basin F i e l d i s s i t u a t e d on a f a u l t e d a n t i c l i n e i n Township 27 North, Range 95 West, Fremont County.

The o i l f i e l d was d i s c o v e r e d

i n 1923, when a w e l l completed i n t h e Cretaceous F r o n t i e r Formation produced economic y i e l d s of n a t u r a l g a s .

Soon t h e r e a f t e r , a d d i t i o n a l

w e l l s s t r u c k o i l i n t h e F r o n t i e r Formation. The Bison Basin F r o n t i e r U n i t w a s approved i n 1939, w i t h Elmer J . Boseke, J r . a s o p e r a t o r .

H e was succeeded i n May, 1956, by Gulf

O i l Corporation.

The F r o n t i e r r e s e r v o i r c o v e r s an area of 270 a c r e s . t h i c k n e s s of t h e pay zone is 75 f e e t .

The a v e r a g e

The F r o n t i e r r e s e r v o i r i s a

l i g h t g r a y , g l a u c o n i t i c conglomerate i n t h e upper o i l - b e a r i n g zones w i t h i n t e r b e d d e d d a r k g r a y t o b l a c k , s i l t y t o arenaceous s h a l e and minor b e n t o n i t e .

Average p o r o s i t y and p e r m e a b i l i t y of t h e F r o n t i e r

are 1 8 p e r c e n t and 150 m i l l i d a r c i e s , r e s p e c t i v e l y . Secondary r e c o v e r y of o i l by w a t e r i n j e c t i o n began i n August, 1971, when t h r e e w e l l s were completed i n a l i n e d r i v e p a t t e r n a t t h e n o r t h e a s t c o r n e r of t h e f i e l d . a c t i v e a s of December, 1979.

Only one of seven i n j e c t i o n w e l l s was Up t o t h a t p o i n t , 7,432,153 b a r r e l s

8 (3.1215 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d i n t o t h e F r o n t i e r

Formation. A p l a n i s c u r r e n t l y b e i n g formulated t o c o n v e r t t h e p i l o t w a t e r f l o o d i n Bison Basin F i e l d t o a f i e l d - w i d e a l k a l i n e w a t e r f l o o d u s i n g d i l u t e (0.2 p e r c e n t NaOH) c a u s t i c soda.

Casing Record:

I n j e c t i o n W e l l #16, T27N-R95W-20 bab, Bison Basin F i e l d , F r o n t i e r U n i t , T o t a l Depth = 1400 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5 /8"

26

5-1/2" 2-3/8" (tubing)

Depth S e t

Amount

43'

35 s a c k s

15.5

1395'

75 s a c k s

-

1343 '

-

Black Mountain F i e l d (12,110,369 b b l s o i l , 113,543 MCF g a s ; 1924-79) A s i n g l e w e l l s a l t w a t e r d i s p o s a l system was p u t i n t o o p e r a t i o n a t

Black Mountain F i e l d i n 1979.

The f i e l d i s l o c a t e d i n Townships 42 and

43 North, Range 9 1 West, Hot S p r i n g s County, and h a s been producing o i l and g a s s i n c e i t s d i s c o v e r y i n 1924.

Texaco, I n c . o p e r a t e s t h e d i s p o s a l

w e l l , which i n j e c t s produced b r i n e i n t o t h e Madison Limestone.

Details

on t h e new system w e r e u n a v a i l a b l e f o r t h i s w r i t i n g .

Blue Gap I1 F i e l d (29,495 b b l s o i l , 2,832,341MCF g a s ; 1974-79) C I G E x p l o r a t i o n Company began o p e r a t i n g a s i n g l e w e l l s a l t w a t e r

d i s p o s a l system a t Blue Gap I1 F i e l d i n 1978.

The f i e l d i s l o c a t e d

i n Township 1 5 North, Range 92 West, Carbon County.

The F o r t Union

Formation is t h e r e c i p i e n t f o r m a t i o n f o r t h e i n j e c t e d b r i n e s . Bower F i e l d (216,925 b b l s o i l , 152,874 MCF g a s ; 1973-79) Teckla U n i t I n 1974, Inexco O i l Company began o p e r a t i o n of a s i n g l e w e l l s a l t w a t e r d i s p o s a l system i n t h e Teckla U n i t of Bower F i e l d .

B r i n e s pro-

duced w i t h o i l from p r o d u c t i o n w e l l s a t Bower F i e l d are i n j e c t e d t o t h e Lewis S h a l e a t a d e p t h of 6,350 f e e t through t h e d i s p o s a l w e l l l o c a t e d i n S e c t i o n 20, Township 37 North, Range 69 West, Converse County. I n j e c t i o n d a t a were a v a i l a b l e o n l y f o r February, 1980.

During t h a t

month, 3,770 b a r r e l s (158,340 g a l l o n s ) of s a l t water were i n j e c t e d t o t h e Lewis Shale a t average i n j e c t i o n p r e s s u r e s ranging between 595 and 6,350 p s i .

Brady F i e l d (24,695,445 b b l s o i l , 88,259,278 MCF gas; 1973-79) Weber Unit The Weber Unit of Brady F i e l d i s t h e c u r r e n t s i t e of an e x t e n s i v e , deep formation, n a t u r a l g a s s t o r a g e i n j e c t i o n p r o j e c t .

The u n i t a r e a

covers p o r t i o n s of Townships 16 and 17 North, Range 101 West, Sweetwater County.

The s t o r a g e p r o j e c t began i n 1975, and has expanded t o a s i x

w e l l system.

The formation being u t i l i z e d f o r s t o r a g e i s t h e Pennsyl-

vanian Weber Sandstone which occurs between 14,150 and 14,275 f e e t below t h e s u r f a c e i n t h e Brady F i e l d a r e a .

A s of March, 1980, 58,418,028

MCF of n a t u r a l gas had been i n j e c t e d t o t h e Weber Sandstone f o r temporary storage.

Average i n j e c t i o n p r e s s u r e s have ranged from 0 t o 4,888 p s i

over t h e d u r a t i o n of t h e p r o j e c t . Mesaverde Unit Champlin Petroleum Company a l s o o p e r a t e s a one w e l l s a l t water d i s p o s a l system a t Brady F i e l d i n t h e Mesaverde Unit.

The p r o j e c t began

i n 1977, w i t h t h e i n j e c t i o n of produced b r i n e t o t h e lower Rock Springs and upper Ericson formations of t h e Mesaverde Group. volume of 2,622,760 b a r r e l s (1.1016 x LO been i n j e c t e d through December, 1979.

8

A cumulative

g a l l o n s ) of s a l t water had

Average p r e s s u r e s of i n j e c t i o n

have ranged from 100 t o 800 p s i during t h e p r o j e c t ' s l i f e t i m e .

The

range of TDS c o n c e n t r a t i o n s of t h e i n j e c t e d b r i n e i s from 92,786 t o 114,815 mg/l.

Casing Record:

S a l t Water Disposal Well #1, T16N-RlOlW-11, Mesaverde Unit.

Casing S i z e 13-3/8" 7"

Wt.

(#/ft)

Amount

48

400'

23

5450'

Brady F i e l d ,

Purpose Surf a c e Long S t r i n g

3-1/2"

I nj e c t i o n Tubing

Breaks F i e l d (392,172 b b l s o i l ; 1976-79) Hembt-Federal Unit A s i n g l e w e l l s a l t water d i s p o s a l system was put i n o p e r a t i o n i n

1977, a t t h e Hembt-Federal Minnelusa Unit of Breaks F i e l d .

The f i e l d

i s l o c a t e d i n e a s t - c e n t r a l Campbell County, Township 52 North, Range 69

West.

Produced Minnelusa b r i n e s a r e i n j e c t e d t o t h e Minnelusa Formation

a t a depth of 7,426 f e e t and an average i n j e c t i o n p r e s s u r e of 1,000 p s i . A s of December, 1979, i n j e c t i o n r e p o r t s from t h e o p e r a t o r , Smith-Fancher

Company, i n d i c a t e t h a t a cumulative volume of 478,977 b a r r e l s (2.0117

7 x 10 g a l l o n s ) of b r i n e have been i n j e c t e d . Bridger Lake Unit (No Production Record) Bridger Lake Unit i s l o c a t e d i n Township 12 North, Range 114 West, Uinta County, and i s t h e p r e s e n t s i t e of a s i n g l e w e l l s a l t water d i s p o s a l system t h a t was put i n t o o p e r a t i o n i n 1969.

S a l t water produced

w i t h o i l a t Bridger Lake i s s e p a r a t e d from t h e o i l and i n j e c t e d i n t o t h e F o r t Union Formation a t a depth of 8,336 f e e t .

A s of December, 1979,

cumulative i n j e c t i o n of produced b r i n e t o t h e F o r t Union was 1,418,930 7 b a r r e l s (5.9595 x 10 g a l l o n s ) .

Formation water w i t h i n t h e F o r t Union

has a NaCl c o n c e n t r a t i o n of 750 mg/l according t o one r e p o r t e d a n a l y s i s . NaCl c o n c e n t r a t i o n s i n t h e i n j e c t e d b r i n e s have been r e p o r t e d a s h i g h a s 6,000-8,000 t i o n system.

mg/l.

There have been no r e p o r t e d problems w i t h t h e i n j e c -

Brooks Ranch F i e l d (2,523,905 b b l s o i l ; 1957-79) Brooks Ranch Unit The Brooks Ranch Unit i s l o c a t e d approximately 12 m i l e s e a s t of Casper, a t t h e west end of t h e Big Muddy a n t i c l i n e on 4,280 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l y owned land.

The f i e l d produces from a

s t r a t i g r a p h i c t r a p on t h e nose of an asymmetrical a n t i c l i n e , w i t h t h e s t e e p f l a n k dipping n o r t h a t 12',

and t h e more g e n t l e s o u t h f l a n k

dipping a t about 5' i n t o a doubly plunging s y n c l i n e .

The s y n c l i n e

s e p a r a t e s t h e Big Muddy s t r u c t u r e from t h e northeastward plunge of t h e Hat S i x a n t i c l i n e . The discovery w e l l a t Brooks Ranch F i e l d was completed i n 1957, i n t h e second F r o n t i e r sand.

The second F r o n t i e r sand h a s an average

p o r o s i t y of 16.9 p e r c e n t , average p e r m e a b i l i t y of 3 . 1 m i l l i d a r c i e s , average pay zone t h i c k n e s s of 7.7 f e e t , and t h i c k e n s toward t h e northwest.

The i n i t i a l mechanism of production from t h e second F r o n t i e r

was s o l u t i o n gas d r i v e . Water i n j e c t i o n i n t h e Brooks Ranch Unit began i n 1967.

Twenty-

seven w e l l s , of which 21 were a c t i v e l y i n j e c t i n g , were s h u t - i n i n February, 1972, due t o t h e l a c k of p r e s s u r e s t i m u l a t i o n a f t e r t h e 8 i n j e c t i o n of 5,894,828 b a r r e l s (2.4758 x 10 g a l l o n s ) of water supplied by a w e l l i n t h e Madison Limestone.

Reservoir c a l c u l a t i o n s , based on

100 p e r c e n t e f f e c t i v e i n j e c t i o n , i n d i c a t e d , t h e o r e t i c a l l y , t h a t i n j e c t i o n had surpassed 140 p e r c e n t f i l l - u p of t h e f r e e gas s a t u r a t i o n phase which e x i s t e d p r i o r t o secondary recovery o p e r a t i o n s . Lack of r e s e r v o i r p r e s s u r e s t i m u l a t i o n , coupled w i t h t h e f a c t t h a t many of t h e i n j e c t i o n w e l l s s t i l l show s u r f a c e p r e s s u r e s of over 1,500 p s i a f t e r 23 months of s h u t - i n s t a t u s , l e d T e r r a Resources, I n c . t o

conclude t h a t re-instatement of f u l l s c a l e i n j e c t i o n o p e r a t i o n s could n o t be economically j u s t i f i e d . A t p r e s e n t (December, 1979), t h e r e i s one a c t i v e i n j e c t i o n w e l l

i n t h e Brooks Ranch Unit.

Cumulative i n j e c t i o n i n t o t h a t w e l l , between

1978 and t h e end of 1979, was 27,610 b a r r e l s (1,159,620 g a l l o n s ) of produced F r o n t i e r Formation water.

Casing r e c o r d s f o r t h e w e l l were

u n a v a i l a b l e a t t h e time of t h i s w r i t i n g . Buck Creek F i e l d (844,958 b b l s o i l , 794,410 MCF gas; 1952-79) Converse Unit The most r e c e n t s a l t water d i s p o s a l system t o come on l i n e i n Wyoming i s t h e s i n g l e w e l l o p e r a t i o n a t Buck Creek F i e l d , Township 36 North, Range 63 West, Niobrara County.

Produced b r i n e from Buck Creek

F i e l d i s i n j e c t e d t o t h e Converse sand of t h e upper Minnelusa Format i o n a t a depth of 5,653 f e e t . between 25 and 50 p s i .

Average i n j e c t i o n p r e s s u r e s have ranged

The i n i t i a l i n j e c t i o n was made during t h e e a r l y

p a r t of 1980, and cumulative i n j e c t i o n t o June, 1980, was 15,666 b a r r e l s (657,972 g a l l o n s ) . Bunker H i l l F i e l d (3,448,744 MCF gas; 1937-79) Bunker H i l l F i e l d i s l o c a t e d i n Townships 26 and 27 North, Range 89 West, Carbon County.

The f i e l d is t h e p r e s e n t s i t e of a two w e l l

n a t u r a l gas s t o r a g e p r o j e c t t h a t was s t a r t e d i n 1972, under t h e o p e r a t i o n of Northern Gas Company.

A s of 1977, 3,448,744 MCF of n a t u r a l gas were

s t o r e d i n t h e Shannon Sandstone a t a depth of 1,471 f e e t .

Burke Ranch F i e l d (6,225,241 b b l s o i l , 195,937 MCF g a s ; 1953-79) Dakota U n i t O i l was d i s c o v e r e d a t Burke Ranch F i e l d i n 1953, upon completion

of a w e l l i n t h e C r e t a c e o u s Dakota sand.

The Dakota U n i t , approved i n

1951, c o v e r s a n a r e a of 1,281.57 a c r e s , of which 923.66 a c r e s a r e f e d e r a l l y owned and t h e remaining 357.91 are p r i v a t e l y owned f e e l a n d s . The Burke Ranch F i e l d Dakota U n i t i s s i t u a t e d on t h e e a s t f l a n k of t h e Casper a r c h , a broad u p l i f t e d a r e a s e p a r a t i n g t h e Wind R i v e r Basin from t h e Powder R i v e r B a s i n , i n t h e e a s t - c e n t r a l p a r t of Natrona County, 24 m i l e s n o r t h of Casper. The Dakota r e s e r v o i r encompasses 1,282 a c r e s and h a s a n a v e r a g e pay zone t h i c k n e s s of 1 2 f e e t .

The a v e r a g e p o r o s i t y and p e r m e a b i l i t y

of t h e Dakota a t w e l l #5 (T37N-R78W-7 millidarcies, respectively.

cdb) a r e 14 p e r c e n t and 29

The Dakota sand i s a f i n e - t o medium-

g r a i n e d w h i t e sand. S e i s m i c work e s t a b l i s h e d a p p r o x i m a t e l y 150 f e e t of s t r u c t u r a l c l o s u r e on t h e t o p of t h e Dakota.

However, p r o d u c t i o n from t h e Dakota

r e s e r v o i r i s b e l i e v e d t o b e s t r a t i g r a p h i c a l l y c o n t r o l l e d by t h e l e n t i c u l a r n a t u r e of t h e e f f e c t i v e p o r o s i t y w i t h i n t h e r e s e r v o i r .

The

p r o d u c i n g energy w i t h i n t h e r e s e r v o i r was o r i g i n a l l y provided by a combination of f l u i d expansion and s o l u t i o n g a s d r i v e . I n J u l y , 1962, a p i l o t w a t e r i n j e c t i o n p r o j e c t was i n i t i a t e d . The p i l o t p r o j e c t was l a t e r expanded t o a f u l l s c a l e p e r i p h e r a l waterflood.

I n j e c t i o n w a t e r i s provided by w a t e r s u p p l y w e l l s completed

i n t h e Parkman Sandstone.

A s of December, 1979, c u m u l a t i v e i n j e c t i o n

8 t o t a l e d 19,827,180 b a r r e l s (8.3274 x 1 0 g a l l o n s ) of w a t e r .

Only f o u r

of 11 i n j e c t i o n w e l l s were a c t i v e a t t h a t time.

Casing r e c o r d s were

u n a v a i l a b l e a t t h e time of t h i s w r i t i n g .

Byron F i e l d (102,519,099 b b l s o i l , 12,146,011 MCF g a s ; 1918-79) Pre-Tensleep Unit The Byron o i l f i e l d i s l o c a t e d j u s t w e s t of L o v e l l , i n Township 56 North, Range 97 West, Big Horn County.

The f i e l d was d i s c o v e r e d i n

1918, b u t i t wasn't u n t i l 1929 t h a t o i l was encountered i n t h e Sundance Formation and 1930 when o i l was found i n t h e Embar Formation and Tensleep Sandstone. S t r u c t u r a l l y , Byron F i e l d i s s i t u a t e d on a northwest-southeast t r e n d i n g , f a u l t e d a n t i c l i n e which d i p s s t e e p l y t o t h e n o r t h e a s t . The Pre-Tensleep Unit covers 3,710.2 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l y owned f e e land.

Waterflooding of t h e Amsden Formation, t o

enhance o i l p r o d u c t i o n , was s t a r t e d i n 1970, u t i l i z i n g produced water from Amsden o i l w e l l s .

A s of December, 1979, t h e only i n j e c t i o n w e l l

i n t h e Pre-Tensleep Unit was t e m p o r a r i l y s h u t - i n .

Cumulative i n j e c t i o n

d a t a and c a s i n g r e c o r d s on t h e w e l l were u n a v a i l a b l e a t t h e time of t h i s writing.

Embar-Tensleep Unit The Embar-Tensleep Unit water i n j e c t i o n p r o j e c t began i n 1973, u s i n g produced w a t e r from nearby Tensleep o i l w e l l s .

The Embar-Tensleep

Unit i s l o c a t e d i n t h e e a s t - c e n t r a l p o r t i o n of Township 56 North, Range 97 West, Big Horn County. S i x t e e n of t h e 2 1 i n j e c t i o n w e l l s were on a c t i v e s t a t u s a s of December, 1979.

I n j e c t i o n d a t a and c a s i n g r e c o r d s f o r t h e w e l l s were

u n a v a i l a b l e a t t h e t i m e of t h i s w r i t i n g .

C-H F i e l d (4,079,934 b b l s o i l , 22,584 MCF g a s ; 1967-79)

Minnelusa U n i t O i l was d i s c o v e r e d i n t h e Minnelusa Formation of C-H F i e l d i n

1967.

I n t h i s a r e a n o r t h e a s t of G i l l e t t e , Wyoming, t h e Minnelusa i s a

sandy, d a r k r e d s h a l e which g r a d e s v e r t i c a l l y downward i n t o a v e r y d o l o m i t i c , medium-grained, b u f f s a n d s t o n e and t h e n i n t o a w h i t e , d e n s e , c r y s t a l l i n e dolomite.

The a v e r a g e p o r o s i t y and p e r m e a b i l i t y of t h e

Minnelusa a r e 1 8 . 3 p e r c e n t and 230 m i l l i d a r c i e s , r e s p e c t i v e l y . r e s e r v o i r p r e s s u r e was 3,300 p s i g .

Original

One y e a r l a t e r , t h e p r e s s u r e had

decreased t o 851 psig. The Minnelusa r e s e r v o i r i n c l u d e s 667 a c r e s .

The r e s e r v o i r b o u n d a r i e s

are d e f i n e d by an o i l - w a t e r c o n t a c t on t h e w e s t e r n s i d e of t h e product i v e area.

The e a s t e r n and n o r t h e r n s i d e s of t h e f i e l d are d e f i n e d by

a p i n c h o u t of t h e porous and permeable sand determined by d r y h o l e s i n o r very near t h e b a r r i e r . When w e l l W-2

(~52GR70W-2) was plugged and abandoned i n 1967,

t h e f o l l o w i n g plugging s c h e d u l e was employed i n o r d e r t o s h u t o f f a l l o i l and w a t e r producing i n t e r v a l s : Depth ( f t )

Cement ( s a c k s )

Casing Record:

I n j e c t i o n W e l l #3, T52N-R70W-2 c a d , C-H Field-Minnelusa U n i t , T o t a l Depth = 7684 f e e t .

Casing S i z e

Wt.

8-5/8" 5-1/2"

(#/ft) 24

1 5 , 5 , 1 7 , 20

Depth S e t

Hole S i z e

Cement

169 '

12-1/4"

130 s a c k s

7680 '

7-7 /8"

400 s a c k s

Camp Creek F i e l d (3,649,088 b b l s o i l ; 1962-79) Dart Unit S a l t water d i s p o s a l a t t h e Dart Unit of Camp Creek F i e l d s t a r t e d i n 1975.

Produced b r i n e was i n j e c t e d i n t o t h e Minnelusa Formation

a t a depth of 7,415 f e e t through a w e l l l o c a t e d i n S e c t i o n 1, Township 54 North, Range 71 West, Campbell County. was s h u t - i n ,

By 1979, t h e d i s p o s a l w e l l

a f t e r a cumulative volume of 6,782 b a r r e l s (284,844 g a l l o n s )

of s a l t water had been i n j e c t e d . Carson F i e l d (998,782 b b l s o i l , 1,954,388 MCF gas; 1969-79) K #2 Unit

I n 1972, Texaco, I n c . began o p e r a t i n g a s a l t water d i s p o s a l w e l l i n t h e K #2 Unit of Carson F i e l d , Township 54 North, Range 73 West, The w e l l i s p e r f o r a t e d i n t h e Muddy Sandstone a t a

Campbell County.

depth of 7,761 f e e t .

By 1979, t h e we91 had been shut-in.

Reported

cumulative i n j e c t i o n t o t h e time of s h u t - i n was 37,492 b a r r e l s (1,574,664 g a l l o n s ) .

Casing Record:

S a l t Water Disposal Well f 2 , T54N-R73W-18 d c , Carson F i e l d , K #2 U n i t , T o t a l Depth = 7904 f e e t .

Casing S i z e 10-3/4" 7" 3-1/2"

Wt.

(#/ft)

Amount

Cement

40.5

582'

425 s a c k s

23,26

7895 '

250 sacks

-

-

South Casper Creek F i el d (10,147,899 b b l s o i l ; 1919-79) Tensleep Unit The South Casper Creek F i e l d Tensleep Unit i s t h e s i t e of one of ~ y o m i n g ' s two hydrothermal i n j e c t i o n p r o j e c t s .

This secondary o i l

recovery method has been i n o p e r a t i o n s i n c e 1974, a t South Casper Creek, and i n v o l v e s e i g h t steam i n j e c t i o n w e l l s , only two of which were s t i l l a c t i v e a s of t h e end of 1979. The Tensleep Unit i s l o c a t e d i n S e c t i o n s 2 and 3 , Township 33 North, Range 8 3 West, Natrona County.

Steam i s i n j e c t e d i n t o t h e

Pennsylvanian Tensleep Sandstone between 2,350 and 2,550 f e e t .

Average

p o r o s i t y and p e r m e a b i l i t y of t h e Tensleep i n t h i s a r e a a r e 16.7 p e r c e n t and 281 m i l l i d a r c i e s .

A s of December, 1979, cumulative steam i n j e c t e d

s i n c e t h e p r o j e c t s t a r t e d was 198,584 MCF. C e l l a r s Ranch F i e l d (4,947,193 b b l s o i l , 2,908 MCF gas; 1960-79) Crow Mountain Unit The Crow Mountain Unit of C e l l a r s Ranch F i e l d h a s , s i n c e 1977, been t h e s i t e of a s i n g l e w e l l s a l t water d i s p o s a l system.

The w e l l

i s l o c a t e d i n S e c t i o n 24, Township 44 North, Range 82 West, Johnson County, and i s completed i n t h e Crow Mountain Formation a t a depth of 5,684 f e e t .

Cumulative i n j e c t i o n through December, 1979, was 1,955,501

7 b a r r e l s (8.2131 x 1 0 g a l l o n s } of produced b r i n e .

The average i n j e c t i o n

p r e s s u r e h a s been c o n s i s t e n t l y around 900 p s i .

Chan F i e l d (3,386,003 b b l s o i l , 4,284,884 MCF g a s ; 1968-79) Muddy Unit The Muddy Unit of Chan F i e l d i s l o c a t e d i n S e c t i o n s 1, 2 , and 11 of Township 56 North, Range 73 West, Campbell County.

O i l was

discovered i n t h e Muddy Sandstone i n 1969. Production a t Chan F i e l d i s from a l e n t i c u l a r sandstone r e s e r v o i r developed a t t h e b a s e of t h e Dynneson Member of t h e Cretaceous Muddy Sandstone.

The r e s e r v o i r i s composed of s h i n g l e - l i k e s h o r e l i n e b a r s

which show h y d r a u l i c communication w i t h one a n o t h e r .

Average p o r o s i t y

and p e r m e a b i l i t y of t h e Muddy r e s e r v o i r a r e 14.2 p e r c e n t and 44 millidarcies, respectively.

The primary producing mechanism i n t h e

r e s e r v o i r was s o l u t i o n g a s d r i v e and t h e o r i g i n a l bottom h o l e p r e s s u r e was 2,017 p s i . Water i n j e c t i o n began i n 1975, u s i n g 85 p e r c e n t f r e s h water from t h e Fox H i l l s Sandstone and Lance Formation which a r e found a t depths between 2,000 and 5,000 f e e t i n t h e Chan F i e l d a r e a .

The r e s t of t h e

water used i n t h e i n j e c t i o n p r o j e c t i s produced water from t h e Muddy Sandstone o i l production w e l l s .

The Fox H i l l s water supply w e l l i s

l o c a t e d i n t h e northwest q u a r t e r of t h e s o u t h e a s t q u a r t e r of S e c t i o n 2, Township 56 North, Range 73 West. a c t i v e a s of December, 1979.

Four of s i x i n j e c t i o n w e l l s were

Cumulative i n j e c t i o n t o t h a t d a t e was

8 3,946,830 b a r r e l s (1.6577 x 10 g a l l o n s ) of w a t e r . Casing Record:

I n j e c t i o n Well #411, T56N-R73W-11 bb, Chan F i e l d , Muddy U n i t , T o t a l Depth = 7095 f e e t .

Casing S i z e

Wt.

8-5/8" 4-1/2"

(#/ft) 24

11,10.5

Hole S i z e

Depth S e t

12-1/4"

200.97' 7095 '

7-7/8"

Cement 175 s a c k s 18 sacks

C i r c l e Ridge F i e l d (20,888,245 b b l s o i l ; 1923-79) Shoshone 63 Unit C i r c l e Ridge F i e l d i s l o c a t e d on t h e Wind River I n d i a n R e s e r v a t i o n i n Township 6 North, Range 2 West, S e c t i o n 6. Shoshone 63 U n i t began i n 1923.

Field operations a t the

The o i l producing formation i s t h e

Darwin Sandstone of ;CJlississippian age.

The Darwin r e s e r v o i r h a s a n

average p o r o s i t y of 1 8 p e r c e n t and an average p e r m e a b i l i t y of 41.7 millidarcies.

Water i n j e c t i o n i n t o t h e Darwin Sandstone was s t a r t e d i n 1977, through t h r e e w e l l s using produced water from t h e Amsden Formation. S i x i n j e c t i o n w e l l s were added i n 1979 and a l l n i n e w e l l s were a c t i v e l y i n j e c t i n g a t t h e end of t h e y e a r .

The cumulative volume of

water i n j e c t e d ( ~ e c e m b e r , 1979) was 356,336 b a r r e l s (14,966,112 gallons).

Information on i n j e c t i o n w e l l c a s i n g was u n a v a i l a b l e a t t h e

time of t h i s w r i t i n g . C l a r e t o n F i e l d (1,309,701 b b l s o i l , 127,178 MCF g a s ; 1950-79) C l a r e t o n o i l f i e l d i s l o c a t e d on t h e e a s t f l a n k of t h e Powder River Basin i n Townships 42 and 43 North, Ranges 65 and 66 West, Weston County.

Oil p r o d u c t i o n i n a l l of t h e C l a r e t o n F i e l d u n i t s i s from t h e

Lower Cretaceous Newcastle Sandstone.

The Newcastle Sandstone i n t h i s

a r e a i s a s u c c e s s i o n of t h i n sandstone, s i l t s t o n e and s h a l e beds.

The

o i l sand of t h e Newcastle i s f i n e - t o medium-grained w i t h s h a l e i n t e r c a l a t i o n s and carbonaceous m a t e r i a l .

The predominant primary energy

s o u r c e f o r t h e Newcastle r e s e r v o i r i s t h e expansion of s o l u t i o n gas. There a r e f o u r u n i t s w i t h i n t h e C l a r e t o n F i e l d t h a t a r e u s i n g water i n j e c t i o n t o enhance o i l recovery from t h e Newcastle r e s e r v o i r . They a r e t h e Clareton-Thorson U n i t , t h e Cotton U n i t , t h e Black Thunder U n i t , and t h e Newcastle Unit.

Clareton-Thorson Unit The Clareton-Thorson Unit of c l a r e t o n F i e l d i n c l u d e s 2,062.74 a c r e s of f e d e r a l and p r i v a t e l y owned f e e land. on November 24, 1967.

The u n i t was approved

Water i n j e c t i ~ ni n t o t h e Newcastle Sandstone

s t a r t e d i n 1 9 6 6 , a n d was expanded t o a f i v e w e l l p r o j e c t one y e a r l a t e r .

Average p o r o s i t y and p e r m e a b i l i t y of t h e Newcastle r e s e r v o i r a t i n j e c t i o n w e l l #28 (T43N-R65W-14 bcc) a r e 9.3 p e r c e n t and 5 m i l l i darcies, respectively. A l l f i v e i n j e c t i o n w e l l s i n t h e Clareton-Thorson Unit were

temporarily s h u t - i n a s of December, 1979.

Cumulative i n j e c t i o n t o

8 t h a t p o i n t was 2,978,637 b a r r e l s (1.251 x 10 g a l l o n s ) . Casing Record : I n j e c t i o n Well #28, ~ 4 3 ~ - ~ 6 5 ~bcc, - 1 4 Clareton Field, Clareton-Thorson U n i t , T o t a l Depth = 6077 f e e t . Casing S i z e

Wt.

(#/ft)

8-518"

24

2-7 18"

?

Hole S i z e

Depth S e t

Cement

12-1/4"

167'

100 sacks

7-718"

6065'

175 sacks

Cotton Unit The Cotton Unit of C l a r e t o n F i e l d i s l o c a t e d i n S e c t i o n s 16 and

1 7 of Township 43 North, Range 65 West, Weston County.

Water i n j e c t i o n

i n t o t h e Newcastle Sandstone began i n 1971 through t h r e e w e l l s .

Fresh

water was s u p p l i e d by a water w e l l i n t h e Fox H i l l s Sandstone ( ~ 4 3 ~ R65W-16 c b ) . By December, 1979, two of t h e i n j e c t i o n w e l l s had been temporarily

shut-in and t h e o t h e r w e l l was permanently shut-in.

Cumulative i n j e c -

t i o n t o t h a t p o i n t was 424,413 b a r r e l s (17,825,346 g a l l o n s ) of water. Black Thunder Unit The Black Thunder Unit of C l a r e t o n F i e l d i s l o c a t e d i n t h e e a s t c e n t r a l p a r t of Township 42 North, Range 66 West, Weston County. Water i n j e c t i o n i n t o t h e Newcastle Sandstone s t a r t e d i n 1960, through one w e l l .

The water supply w e l l f o r t h e waterflood p r o j e c t was completed

i n t h e Fox H i l l s Sandstone.

The p i l o t f l o o d was expanded t o 9 i n j e c t i o n

w e l l s i n 1962, and e v e n t u a l l y grew t o 17 w e l l s by 1967.

A s of December,

1979, a l l 17 i n j e c t o r s were t e m p o r a r i l y s h u t - i n and 8,590,160 b a r r e l s 8 (3.6079 x 10 g a l l o n s ) of water had been i n j e c t e d s i n c e 1960.

Casing

d a t a on t h e i n j e c t i o n w e l l s were u n a v a i l a b l e f o r t h i s w r i t i n g . Newcastle Unit The Newcastle Unit of C l a r e t o n F i e l d covers 9,977 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l y owned f e e land i n southwestern Weston County. Water i n j e c t i o n i n t o t h e Newcastle r e s e r v o i r was i n i t i a t e d i n 1960, and expanded t o a f u l l s c a l e p r o j e c t w i t h 46 i n j e c t i o n w e l l s by 1968.

I n j e c t i o n water was s u p p l i e d by w e l l s completed i n t h e Upper

Cretaceous Fox H i l l s Sandstone.

A s of December, 1979, 29,312,628

9 b a r r e l s (1.2311 x 10 g a l l o n s ) of w a t e r had been i n j e c t e d i n t o t h e Newcastle r e s e r v o i r and a l l 46 of t h e i n j e c t i o n w e l l s had been permanently shut-in. A two w e l l s a l t w a t e r d i s p o s a l system s t a r t e d i n 1975, a t t h e

C l a r e t o n F i e l d Newcastle Unit.

Both w e l l s a r e l o c a t e d i n Township 42

North, Range 65 West and i n j e c t water from C l a r e t o n F i e l d production w e l l s i n t o t h e Newcastle Sandstone.

A s of December, 1979, 274,602

b a r r e l s (11.,533,284 g a l l o n s ) of b r i n e had been i n j e c t e d .

The maximum

average i n j e c t i o n p r e s s u r e d u r i n g t h e e n t i r e p r o j e c t h a s been 3,200 p s i . Casing Record:

I n j e c t i o n Well #1149, T43N-R65W-29 bbd, C l a r e t o n F i e l d , Newcastle U n i t , T o t a l Depth = 6450 f e e t .

Casing S i z e 10-314" 5-1/2"

Wt.

( m t )

32.75

14

Depth S e t

Cement

157 '

100 s a c k s

6447 '

75 s a c k s

Cody F i e l d (723,976 b b l s o i l ; 1976-79) Horner Unit D i s p o s a l of produced s a l t water b r i n e s i n t o t h e Morrison Formation began i n 1978, a t Cody F i e l d i n Township 53 North, Range 101 West, Park County.

One w e l l , i n t r a c t 39, h a s been t h e only i n j e c t o r i n t h e

system and through J u l y , 1979, had disposed of a cumulative volume of 164,773 b a r r e l s (6,920,466 g a l l o n s ) of s a l t water. p r e s s u r e s have been around 1,500 p s i .

Average i n j e c t i o n

I n j e c t e d water i s from production

w e l l s i n t h e Tensleep Sandstone and Phosphoria Formation. Cole Creek F i e l d (16,967,267 b b l s o i l , 501,232 MCF g a s ; 1938-79) A u n i t agreement f o r t h e development and o p e r a t i o n of t h e Cole

Creek F i e l d was approved i n 1938, following t h e d i s c o v e r y of o i l i n t h e Lakota sand.

Production from t h e Shannon Sandstone began t h r e e y e a r s

later. The f i e l d i s l o c a t e d i n Township 35 North, Range 77 West, i n Natrona County, j u s t n o r t h e a s t of Casper, Wyoming. a northwest-southeast

It is s i t u a t e d on

t r e n d i n g a n t i c l i n e and hydrocarbon entrapment i s

provided by t h e s t r u c t u r e and s t r a t i g r a p h y of t h e a n t i c l i n e .

Shannon Unit The Shannon r e s e r v o i r covers an a r e a of 1,653 a c r e s w i t h a n average pay zone t h i c k n e s s of 17 f e e t , an average p o r o s i t y of 19 p e r c e n t , and an average p e r m e a b i l i t y of 56 m i l l i d a r c i e s .

A peripheral pattern

of water i n j e c t i o n w e l l s was p u t i n t o o p e r a t i o n i n February, 1946, t o m a i n t a i n bottom h o l e p r e s s u r e s i n t h e r e s e r v o i r , thereby i n c r e a s i n g t h e recovery of o i l from t h e Shannon sand.

Water f o r t h e i n j e c t i o n p r o j e c t

was o b t a i n e d from t h e Upper Cretaceous Parkman Sandstone.

I n j e c t i o n was terminated i n A p r i l , 1977, when i t was estimated t h a t 99.9 p e r c e n t of t h e Shannon r e s e r v e had been recovered,

The cumulative

volume of water i n j e c t e d t o t h a t time was 20,114,806 b a r r e l s (8.4482 8 x 10 g a l l o n s ) through 20 i n j e c t i o n w e l l s . Dakota "A" Unit The Dakota "A" Unit of Cole Creek F i e l d was approved i n 1965, and covers 995 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d , of t h e Dakota r e s e r v o i r ranges from two t o 20 f e e t .

The pay t h i c k n e s s I n 1965, water

i n j e c t i o n i n t o t h e Dakota r e s e r v o i r began through t h r e e w e l l s , u t i l i z i n g water from t h e Shannon Unit supply w e l l completed i n t h e Parkman Sandstone.

L a t e r t h e Parkman water was supplemented w i t h t r e a t e d pro-

duced water from t h e Dakota sand.

A s of December, 1979, 20,444,756

8 b a r r e l s (8,5868 x 10 g a l l o n s ) of water had been i n j e c t e d through f i v e w e l l s , f o u r of which a r e c u r r e n t l y a c t i v e .

Dakota Unit The Dakota Unit of Cole Creek F i e l d i s l o c a t e d j u s t t o t h e northw e s t of t h e Dakota "A" Unit.

Water i n j e c t i o n began i n 1969, w i t h water

from t h e Parkman sand through one w e l l and was expanded t o a seven w e l l system by 1976.

A s of December, 1979, a l l of t h e w e l l s had been shut-in.

8 Cumulative i n j e c t i o n t o t h a t p o i n t was 5,410,063 b a r r e l s (2.2722 x 10

gallons). Case Record:

Casing S i z e 8-5 /8" 5-112"

I n j e c t i o n Well #33, T35N-R77W-16 cba, Cole Creek F i e l d , Dakota U n i t , T o t a l Depth = 8098 f e e t . Wt.

(#/ft) 24

14,15-1/2,17

Depth S e t

Hole S i z e

Cement

524'

12-1/4"

300 sacks

8063'

7-7 18"

150 sacks

South Cole Creek F i e l d (15,834,514 b b l s o i l , 18,557 MCF gas; 1948-79) Dakota Unit South Cole Creek F i e l d was discovered i n 1948, w i t h t h e completion of a w e l l i n t h e Lakota Sandstone,

I n 1950, another w e l l was completed

i n t h e Lower Cretaceous Dakota sand, a h i g h l y f r a c t u r e d , s h a l e y sand r e s e r v o i r found a t an average depth of 8,250 f e e t w i t h an average pay t h i c k n e s s of 15 f e e t , average p o r o s i t y of 11.5 p e r c e n t , and average p e r m e a b i l i t y of 20.6 m i l l i d a r c i e s .

The Dakota Unit covers an a r e a of

1,165 a c r e s of f e d e r a l l y and p r i v a t e l y owned land and i s s i t u a t e d on t h e same northwest-southeast t r e n d i n g a n t i c l i n e a s t h e Cole Creek F i e l d . Production i s l i m i t e d on t h e n o r t h , e a s t , and s o u t h by t h e oil-water c o n t a c t and on t h e west by d e c r e a s i n g p e r m e a b i l i t y .

The d r i v e mechanism

of t h e Dakota r e s e r v o i r h a s r e p o r t e d l y been provided by t h e expansion of s o l u t i o n gas and formation f l u i d . Water i n j e c t i o n i n t o t h e Dakota r e s e r v o i r s t a r t e d i n 1968, using produced water from t h e Dakota r e s e r v o i r .

F i v e of 23 e x i s t i n g i n j e c t i o n

w e l l s were s t i l l a c t i v e i n December, 1979, and cumulative i n j e c t i o n 9 t o t h a t time was 28,264,292 b a r r e l s (1.1871 x 10 g a l l o n s ) of water. Shannon-Lakota U n i t s The Shannon and Lakota u n i t s of South Cole Creek F i e l d a r e l o c a t e d i n S e c t i o n s 7, 1 7 , 18, and 20 of Township 34 North, Range 76 West. The Shannon Unit covers 210 a c r e s of f e d e r a l l y owned land and 160 a c r e s of p r i v a t e l y owned f e e land.

The Lakota r e s e r v o i r c o n t a i n s 470

a c r e s and h a s an average pay zone t h i c k n e s s of 20 f e e t . r e s e r v a i r producing mechanism was a n a t u r a l water d r i v e .

The i n i t i a l

The Shannon Sandstone i s an Upper Cretaceous, medium- t o coarseg r a i n e d , g l a u c o n i t i c sand w i t h an average p e r m e a b i l i t y of 54 m i l l i d a r c i e s and an average p o r o s i t y of 18.7 p e r c e n t .

The n e t productive i n t e r v a l

h a s an average t h i c k n e s s of 7.5 f e e t . The f i r s t i n j e c t i o n s of water i n t o t h e Lakota Sandstone took p l a c e i n 1960, and u t i l i z e d water from t h e Cole Creek and South Cole Creek F i e l d waterflood systems.

Current e s t i m a t e s (December, 1979) of t h e

volume of water i n j e c t e d i n t o t h e Shannon and Lakota r e s e r v o i r s t o t a l 8 5,838,258 b a r r e l s (2.4521 x 10 g a l l o n s ) through f o u r a c t i v e i n j e c t i o n

wells--three

i n t h e Lakota and one i n t h e Shannon Sandstone.

Collums F i e l d (5,578,551 b b l s o i l , 6,722,091 MCF gas; 1969-79) Collums Unit Collums o i l f i e l d covers 4,681.96 a c r e s of f e d e r a l and p r i v a t e land i n Township 55 North, Range 73 West, Campbell County. of i n i t i a l f i e l d o p e r a t i o n s was 1969.

The year

Water i n j e c t i o n i n t o t h e Fluddy

Sandstone was i n i t i a t e d i n 1970, through 7 w e l l s , and by 1977, had been expanded t o 1 3 w e l l s .

By 1980, a l l of t h e i n j e c t i o n w e l l s had been

temporarily shut-in. The Muddy r e s e r v o i r a t w e l l /I10 (T55N-R73W-9 aad) i s 110 f e e t t h i c k and has an average p o r o s i t y and average p e r m e a b i l i t y of 19.3 p e r c e n t and 62.6 m i l l i d a r c i e s , r e s p e c t i v e l y .

Cumulative i n j e c t i o n

8 volume a s of December, 1979, was 18,995,327 b a r r e l s (7.978 x 10 g a l l o n s ) of f r e s h water from t h e Lance Formation.

Cooper Cove F i e l d (1,662,041 b b l s o i l , 492,989 MCF gas; 1944-79) Cooper Cove Unit The p r o d u c t i v e a r e a of Cooper Cove F i e l d i s approximately 2.5 m i l e s long, less than one-quarter m i l e wide and s i t u a t e d a t o p a t h i n northwest-trending a n t i c l i n e c h a r a c t e r i z e d by s t e e p d i p s on both flanks.

The f i e l d i s l o c a t e d i n Township 1 8 North, Range 77 West,

Carbon County, and was discovered i n 1944, when a productive w e l l was completed i n t h e Dakota sand.

The f i r s t w e l l i n t h e Muddy sand was

completed i n 1963. Commingled production from w e l l s i n t h e Muddy Sandstone and Dakota sand i s bounded on t h e n o r t h by a north-south t r e n d i n g t h r u s t f a u l t which s e p a r a t e s t h e Muddy r e s e r v o i r s a t Cooper Cove and Dutton Creek f i e l d s .

On t h e e a s t , west, and s o u t h s i d e s t h e r e s e r v o i r i s

bounded by an oil-water c o n t a c t a t an e l e v a t i o n of about 2,920 f e e t

.

(MSL)

The Dakota r e s e r v o i r produces by n a t u r a l water d r i v e i n c o n t r a s t t o t h e Muddy sand which produces by expansion of r e s e r v o i r f l u i d . Primary recovery from t h e Muddy r e s e r v o i r was approximately 9 p e r c e n t of t h e o i l i n p l a c e and i t i s estimated t h a t another 12 p e r c e n t w i l l be recovered by secondary i n j e c t i o n . Water i n j e c t i o n i n t o t h e Muddy sand began i n 1967, through 4 w e l l s and was expanded t o 6 w e l l s i n 1975.

The most r e c e n t i n j e c t i o n r e p o r t s

a v a i l a b l e from t h e f i l e s of t h e Wyoming O i l and Gas Commission a r e from J u l y , 1975, and r e p o r t t h a t a cumulative t o t a l of 2,999,722 b a r r e l s (1.2599 x

lo8

g a l l o n s ) of water had been i n j e c t e d .

Casing Record:

I n j e c t i o n Well #11, T18N-R77W-20 cdb, Cooper Cove F i e l d , Cooper Cove U n i t , T o t a l Depth = 4984 f e e t .

Casing Size

Hole S i z e

Wt. ( m t )

Depth Set

Cement

10-3/4"

15"

32.75

298'

1100 s a c k s

4984'

200sacks

7"

9"

20

Purpose Surface Injection

Cottonwood Creek F i e l d (43,239,706 b b l s o i l , 39,392,567 MCF g a s ; 1953-79) Cottonwood Creek U n i t Cottonwood Creek o i l f i e l d was d i s c o v e r e d i n 1953, when a w e l l was completed i n t h e Phosphoria Formation.

The f i e l d i s l o c a t e d i n

Township 47 North, Ranges 90 and 9 1 West, i n Washakie County.

Cottonwood

Creek U n i t c o n t a i n e d 32,979 a c r e s when i t was approved i n 1959, b u t by 1968, t h e area had been reduced t o 14,227 a c r e s . of t h e Phosphoria pay zone i s 20 f e e t .

The a v e r a g e t h i c k n e s s

Hydrocarbon entrapment o c c u r s

n e a r t h e c r e s t of t h e s t r u c t u r e where porous dolomite undergoes a f a c i e s change t o r e d s h a l e .

On t h e east s i d e of t h e f i e l d t h e upper

Phosphoria producing zone i s a t a d e p t h of 5,000 f e e t , whereas on t h e west s i d e of t h e f i e l d i t i s 10,000 f e e t deep. Gas and w a t e r i n j e c t i o n i n t o t h e Phosphoria began i n 1958 and 1959, r e s p e c t i v e l y .

L a t e i n 1962, i t was d i s c o v e r e d t h a t w h i l e t h e

g a s and w a t e r i n j e c t i o n programs had i n c r e a s e d t h e r e s e r v o i r p r e s s u r e , o i l p r o d u c t i o n had d e c r e a s e d .

Gas i n j e c t i o n was stopped i n l a t e 1964,

and a d e t a i l e d f i e l d s t u d y was made. The f i e l d was t h e n d i v i d e d i n t o t h r e e areas--two

t h a t were

responding normally t o w a t e r i n j e c t i o n and one t h a t was e x t e n s i v e l y f r a c t u r e d and d i d n o t respond t o i n j e c t i o n . program was s t a r t e d i n t h e f r a c t u r e d a r e a .

A "flowback" o r " i m b i b i t i o n " Imbibition is a process

u t i l i z e d i n h e a v i l y f r a c t u r e d r e s e r v o i r s whereby t h e major f r a c t u r e i n t h e a r e a i s i n j e c t e d w i t h water.

The i n j e c t i o n w e l l i s then shut-in

and t h e water m i g r a t e s from t h e major f r a c t u r e i n t o t h e smaller f r a c t u r e s and d i s p l a c e s o i l o u t i n t o t h e major f r a c t u r e .

The i n j e c t i o n

w e l l .then becomes a production w e l l and t h e d i s p l a c e d o i l i s pumped from t h e major f r a c t u r e . The water supply f o r t h e Cottonwood Creek Unit i n j e c t i o n p r o j e c t i s provided by t h e Madison Limestone through s e v e r a l water supply w e l l s .

Produced Phosphoria water i s a l s o u t i l i z e d f o r i n j e c t i o n .

December,

1979, i n j e c t i o n r e p o r t s i n d i c a t e d t h a t 17 of 46 e x i s t i n g w e l l s were actively injecting.

Cumulative i n j e c t i o n was 86,444,219 b a r r e l s

9 (3.6307 x 10 g a l l o n s ) of water a t t h a t time. Casing Record:

I n j e c t i o n Well 8106, T47N-R91W-13 cd, Cottonwood Creek F i e l d , Cottonwood Creek U n i t , T o t a l Depth = 7740 f e e t .

Casing S i z e

Wt.

9-5/8" 7"

(#/ft)

Hole S i z e

Depth S e t

Cement

32.3

12-1/4"

343'

350 sacks

20,23,26

8-3/4"

7739'

300 sacks

Phosphoria Unit The Phosphoria Unit of Cottonwood Creek F i e l d covers 4,155.38 a c r e s of f e d e r a l and s t a t e land.

Of t h e u n i t a r e a , 2,620 a c r e s a r e u n d e r l a i n

by p r o d u c t i v e r e s e r v o i r rock w i t h an average n e t pay t h i c k n e s s of 20 feet.

The average p o r o s i t y and p e r m e a b i l i t y of t h e dolomite a r e 7 1

p e r c e n t and 18.3 m i l l i d a r c i e s , r e s p e c t i v e l y , w i t h v e r t i c a l f r a c t u r i n g common.

Hydrocarbon entrapment occurs i n an a l g a l r e e f d e p o s i t which

t r e n d s northwest t o s o u t h e a s t .

The primary mechanism of r e s e r v o i r

production i s by expansion of r e s e r v o i r f l u i d s .

An a d d i t i o n a l 920,000

b a r r e l s of o i l a r e expected t o be recovered by water i n j e c t i o n .

An

e s t i m a t e d 23 m i l l i o n b a r r e l s of water w i l l be r e q u i r e d f o r t h e remainder of t h e secondary recovery p r o j e c t . 8 A s of December, 1979, 4,415,850 b a r r e l s (1.8547 x 10 g a l l o n s ) of Madison Limestone water had been i n j e c t e d through two a c t i v e w e l l s i n t h e Phosphoria Formation. Coyote Creek F i e l d (20,443,800 b b l s o i l , 24,545,381 MCF gas; 1958-79) Watt "A" Unit The Watt "A" Unit of Coyote Creek i s l o c a t e d i n t h e southwest corner of Crook County.

O i l i s produced from t h e Dakota r e s e r v o i r , a

f i n e - t o coarse-grained sandstone w i t h good p o r o s i t y and p e r m e a b i l i t y . Water i n j e c t i o n began i n 1971, through w e l l #33-28 using produced water from t h e Dakota sand.

Two i n j e c t o r s were added i n 1975, and

a d d i t i o n a l water was provided by a w e l l i n t h e Fox H i l l s Sandstone. The t h i c k n e s s of t h e i n j e c t e d Dakota i n t e r v a l ranges from 78 t o 115 feet.

Recent i n j e c t i o n r e p o r t s (December, 1979) i n d i c a t e t h a t 4,455,214

8 b a r r e l s (1.8712 x 10 g a l l o n s ) of water have been i n j e c t e d s i n c e t h e project started. Casing Record: Casing S i z e 9-518'' 5-1/2"

I n j e c t i o n Well #33-28, T49N-R68W-28 db, Coyote Creek F i e l d , Watt "A" U n i t , T o t a l Depth = 6410 f e e t . Wt.

(#/ft) 32.3

14,15.5

Hole S i z e

Depth S e t

Cement

12-1/4"

165 '

100 sacks

8-314"

6400'

125 sacks

Watt "Btt Unit Watt "B" 11

Unit of Coyote Creek F i e l d i s l o c a t e d j u s t s o u t h of Watt

A 11 Unit i n t h e extreme northwest corner of Weston County.

Water

i n j e c t i o n i n t o t h e Dakota r e s e r v o i r s t a r t e d i n 1975, u t i l i z i n g produced w a t e r from t h e Dakota and f r e s h Fox H i l l s Sandstone w a t e r . According t o most r e c e n t O i l and Gas Commission s t a t i s t i c s 8 (December, 1 9 7 9 ) , 3,437,361 b a r r e l s (1.4437 x 1 0 g a l l o n s ) of w a t e r have been i n j e c t e d i n t o t h e Dakota r e s e r v o i r through t h r e e c u r r e n t l y active wells. Kewanee, Buttram U n i t A p a i r of s a l t w a t e r d i s p o s a l w e l l s were p u t i n t o o p e r a t i o n a t Coyote Creek F i e l d i n 1975.

The w e l l s a r e p a r t of t h e Kewanee, Buttram

U n i t and a r e l o c a t e d i n S e c t i o n 3, Township 48 North, Range 68 West, and S e c t i o n 33, Township 49 North, Range 68 West, Weston County. Produced b r i n e from around Coyote Creek F i e l d i s i n j e c t e d t o t h e Dakota sand a t a v e r a g e i n j e c t i o n p r e s s u r e s between 0 and 20 p s i . of December, 1979, 487,560 b a r r e l s (2.0477 x LO

7

As

g a l l o n s ) of b r i n e had

been i n j e c t e d s i n c e t h e s t a r t of t h e p r o j e c t .

South Coyote Creek F i e l d (3,249,987 b b l s o i l , 1,266,319 MCF g a s ; 1963-79) Turner U n i t The Turner U n i t of South Coyote Creek F i e l d began o p e r a t i n g i n 1963, w i t h t h e p r o d u c t i o n of o i l from t h e Upper C r e t a c e o u s Turner Sandstone.

Average p o r o s i t y and p e r m e a b i l i t y of t h e Turner a t w e l l #10

(T48N-R68W-24

d c ) a r e 1 4 . 3 p e r c e n t and 4 . 1 m i l l i d a r c i e s , r e s p e c t i v e l y .

Water i n j e c t i o n f o r secondary r e c o v e r y purposes was f i r s t u t i l i z e d i n 1968.

F r e s h w a t e r from t h e Fox H i l l s Sandstone was b e i n g i n j e c t e d

through 1 2 w e l l s by 1972.

A s of J a n u a r y , 1980, a 1 1 of t h e w e l l s had

been t e m p o r a r i l y s h u t - i n and no c u m u l a t i v e i n j e c t i o n d a t a were a v a i l a b l e for the unit.

Casing Record: Casing S i z e

I n j e c t i o n W e l l #2, T48N-R68W-24 a c , South Coyote Creek F i e l d , Turner U n i t , T o t a l Depth = 5430 f e e t (#/ft)

Wt.

8-5 / 8"

24

4-1/2"

11.5

Hole S i z e

Depth S e t

12-1/2"

172'

7-7 18"

Cement 110 s a c k s (2% c c )

5428'

150 s a c k s (50150 pozmix, 2% g e l w i t h 7# ~ a ~ l l s a c k )

Boxelder D r a w U n i t The Boxelder Draw U n i t of South Coyote Creek F i e l d i s l o c a t e d i n Township 48 North, Range 67 West, S e c t i o n 1 9 , Weston County.

Injection

of water from t h e s h a l l o w Lance Formation s t a r t e d i n 1975, through w e l l # L L ~ . Water q u a l i t y a n a l y s e s on w a t e r b e i n g i n j e c t e d through w e l l #4 showed r i c h c o n c e n t r a t i o n s of s u l f a t e (650 ppm) and c h l o r i d e (450 ppm). 7 December, 1979, d a t a i n d i c a t e d t h a t 491,063 b a r r e l s (2.0625 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d through t h r e e a c t i v e w e l l s .

Casing Record:

I n j e c t i o n Well 84, T48N-R67W-19 b c , South Coyote Creek F i e l d , Boxelder Draw U n i t , T o t a l Depth = 5275 f e e t .

Casing S i z e

Wt.

( m t )

8-518"

24

4-1/2"

9.5

Hole S i z e

Depth S e t

11" 7-7 18"

Cement

167'

125 s a c k s

5275'

130 s a c k s

Crooks Gap F i e l d (12,566,952 b b l s o i l , 1,238,724 MCF g a s ; 1944-79) Crooks Gap U n i t Crooks Gap F i e l d i s l o c a t e d i n Township 28 North, Range 93 West, Fremont County, and i s t h e s i t e of a s a l t w a t e r d i s p o s a l w e l l completed i n t h e Lakota Sandstone a t a d e p t h of 5,286 f e e t .

The w e l l was g u t

i n t o o p e r a t i o n i n 1964, by Amoco P r o d u c t i o n Company.

A s of December,

8 1979, c u m u l a t i v e i n j e c t i o n w a s 18,859,691 b a r r e l s (7.9211 x 1 0 g a l l o n s )

of produced b r i n e .

The a v e r a g e i n j e c t i o n p r e s s u r e d u r i n g t h e p r o j e c t ' s

l i f e t i m e h a s v a r i e d between 120 and 150 p s i . Casing Record:

S a l t Water D i s p o s a l W e l l # 3 , T28N-R93W-13 a a d , Crooks Gap F i e l d , Crooks Gap U n i t , T o t a l Depth = 5500 f e e t

Casing S i z e 5-1/2"

Wt.

(#/ft) 14,15

Depth S e t

Cement

5500

500 s a c k s (cement t o p a t 4300')

Dead Horse Creek F i e l d (9,720,790 b b l s o i l , 2,870,641 MCF g a s ; 1957-79) The f i r s t o i l p r o d u c t i o n from t h e Mesaverde Group of t h e Powder R i v e r Basin o c c u r r e d i n l 9 5 7 , w h e n a w e l l was completed i n t h e Parkman Sandstone a t Dead Horse Creek o i l f i e l d .

The f i e l d i s l o c a t e d i n

Townships 47, 48, and 49 North, Ranges 75 and 76 West, Campbell County. Dead Horse Creek F i e l d c o n s i s t s of t h r e e u n i t i z e d a r e a s - - t h e C a b a l l o U n i t , o p e r a t e d by S t o v a l l O i l Company; t h e North Block U n i t , o p e r a t e d by Farmers Union C e n t r a l Exchange, I n c ; and t h e Hippus 1 A U n i t , o p e r a t e d by Northern P r o d u c t i o n Company, I n c . The Parkman Sandstone u n d e r l y i n g t h e Dead Horse Creek F i e l d i s an o f f s h o r e b a r d e p o s i t composed of f i n e - t o medium-grained s a n d s t o n e w i t h a v e r a g e p o r o s i t y and p e r m e a b i l i t y of 1 8 p e r c e n t and 50 m i l l i d a r c i e s , respectively.

A l l t h r e e u n i t s produce from t h e Parkman r e s e r v o i r .

However, e a s t - w e s t t r e n d i n g f a u l t s i n S e c t i o n s 1 3 and 25, Township 49 North, Range 76 West, may d i v i d e t h e Parkman i n t o t h r e e s e p a r a t e reservoirs.

L i m i t s of p r o d u c t i o n a r e d e f i n e d by t h e o i l - w a t e r c o n t a c t

on t h e w e s t and a p i n c h o u t of t h e sandy r e s e r v o i r r o c k updip t o t h e east.

D r i l l s t e m test d a t a y i e l d evidence t h a t t h e water t a b l e i n t h e

a r e a i s i r r e g u l a r and t h a t t h e e l e v a t i o n of t h e o i l - w a t e r c o n t a c t may be variable.

North Block Unit The North Block Unit of Dead Horse Creek F i e l d c o n t a i n s 2,652 a c r e s of f e d e r a l and p r i v a t e land.

The North Block r e s e r v o i r covers

approximately 2,100 a c r e s w i t h an average pay zone t h i c k n e s s of 15 feet.

I n j e c t i o n t o t h e r e s e r v o i r began i n 1962, w i t h a p i l o t water-

f l o o d p r o j e c t and was expanded t o a f u l l s c a l e flood i n 1964.

Water

i s i n j e c t e d along t h e oil-water c o n t a c t on t h e west s i d e of t h e r e s e r -

voir.

Through December, 1979, 8 of t h e 11 i n j e c t i o n w e l l s were l i s t e d

as active.

Cumulative i n j e c t i o n t o t a l e d 5,556,461 b a r r e l s (2.3337 x

8 10 g a l l o n s ) of water from t h e F o r t Union Formation. Caballo Unit The Parkman r e s e r v o i r of t h e Caballo Unit covers 2,340 a c r e s and has an average pay zone t h i c k n e s s of 10 f e e t .

The overlying Caballo

Unit p a r t i c i p a t i n g a r e a i n c l u d e s 4,280 a c r e s of f e d e r a l and s t a t e land. I n 1963, a secondary recovery waterflood p r o j e c t was i n i t i a t e d u t i l i z i n g a s t a n d a r d 5-spot w e l l p a t t e r n .

I n j e c t e d water i s s u p p l i e d

by a water supply w e l l i n t h e F o r t Union Formation and by producing w e l l s i n t h e Parkman sand.

Four of t h e s i x Caballo Unit i n j e c t o r s

were s t i l l a c t i v e a s of December, 1979.

Cumulative i n j e c t i o n t o t h a t

8 time was 4,229,487 b a r r e l s (1.7764 x 10 g a l l o n s ) of water.

Casing

d a t a were u n a v a i l a b l e a t t h e time of t h i s w r i t i n g . South Dead Horse Creek F i e l d (581,250 b b l s o i l ; 1961-79) Hippus 1 A Unit The Hippus LA Unit of Dead Horse Creek F i e l d i s l o c a t e d i n Township 47 North, Range 75 West, S e c t i o n 10, Campbell County.

Disposal of

produced b r i n e s i n t o t h e Parkman Sandstone began i n 1976, through t h e

Hippus #lA Well (T47N-R75W-10

dc) a t a depth of 7,136 f e e t .

I n 1979,

t h e w e l l was converted t o a secondary recovery water i n j e c t i o n w e l l . During t h e f i r s t y e a r , 8,485 b a r r e l s (365,370 g a l l o n s ) were i n j e c t e d into the reservoir. Casing Record:

I n j e c t i o n Well #1A, T47N-R75W-10 dc, Dead Horse Creek F i e l d , Hippus I A U n i t , T o t a l Depth = 7319 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

8-5 / 8"

24

312'

4-1/2"

11.6

7287 '

Perforations

Purpose Surf a c e

7136-7257

Injection

Deadman Creek F i e l d (407,687 b b l s o i l ; 1973-79) Deadman Creek Unit Deadman Creek F i e l d i s l o c a t e d i n Crook County approximately 20 m i l e s n o r t h of Moorcroft, Wyoming.

O i l was discovered i n 1973,

i n a d i s c r e t e sand body w i t h i n t h e Minnelusa Formation, known a s t h e "Lower ' B '

P o r o s i t y Zone"'.

The productive ( g r e a t e r than 12

p e r c e n t p o r o s i t y ) zone i s 362 a c r e s , w i t h an average pay t h i c k n e s s of 1 8 f e e t .

Average p o r o s i t y w i t h i n t h e r e s e r v o i r i s 17.6 p e r c e n t .

Water i n j e c t i o n i n t o t h e Minnelusa "B"

zone began i n 1979,

through w e l l #23-18 (T53N-R67W-18 ca) w i t h f r e s h and produced water from t h e Minnelusa "C"

and "B"

zones, r e s p e c t i v e l y .

By t h e end of

1979, 133,511 b a r r e l s (5,607,462 g a l l o n s ) of water had been i n j e c t e d . A water q u a l i t y a n a l y s i s of formation water i n t h e lower "B"

i n d i c a t e d very h i g h TDS (21,177 ppm) water.

zone

Dewey Dome F i e l d (8,979 b b l s o i l ; 1936-79) Bradley U n i t The Dewey Dome F i e l d , l o c a t e d i n Township 42 North, Range 6 1 West, S e c t i o n 36, Weston County, was d i s c o v e r e d i n 1936.

O i l was produced

from t h e Sundance Formation. Between 1967 and 1974, w a t e r from t h e Dakota and Lakota s a n d s was i n j e c t e d i n t o t h e Sundance r e s e r v o i r as p a r t of a r e c o v e r y enhancement p r o j e c t .

During t h a t time 690,700 b a r r e l s (29,009,400 g a l l o n s )

of w a t e r were i n j e c t e d through two w e l l s .

I n 1974, b o t h w e l l s were

s h u t - i n by o r d e r of t h e Wyoming O i l and Gas Commission. f o r t h e o r d e r was n o t d i s c l o s e d .

The r e a s o n

Primary p r o d u c t i o n of o i l , however,

h a s continued d e s p i t e t h e abandonment of t h e i n j e c t i o n p r o j e c t . Diamond Ranch F i e l d (770,527 b b l s o i l , 121,151 MCF gas; 1957-79) Lakota U n i t Diamond Ranch F i e l d i s l o c a t e d i n Township 20 North, Range 7 8 West, Carbon County.

The Lakota U n i t i s t h e s i t e of an a c t i v e one w e l l

s a l t w a t e r d i s p o s a l system t h a t was p u t i n t o o p e r a t i o n i n 1978, by Marathon O i l Company.

The i n j e c t e d f o r m a t i o n i s t h e Lakota Sandstone,

which r e c e i v e d a volume of 8,899 b a r r e l s (373,758 g a l l o n s ) d u r i n g t h e month of September, 1979, t h e o n l y month f o r which i n j e c t i o n d a t a were a v a i l a b l e .

D i l l i n g e r Ranch F i e l d (11,062,497 b b l s o i l , 315,613 MCF g a s ; 1964-79) D i l l i n g e r Ranch U n i t D i l l i n g e r Ranch F i e l d was d i s c o v e r e d i n March, 1964, and u n i t i z e d f o r w a t e r i n j e c t i o n i n December, 1966.

The D i l l i n g e r Ranch U n i t

p a r t i c i p a t i n g a r e a i n c l u d e s 2,264.25 a c r e s of f e d e r a l , s t a t e , and

p r i v a t e l a n d i n e a s t - c e n t r a l Campbell County. Minnelusa "B"

O i l i s produced from t h e

pay zone, a v a r i a b l y porous zone of f o u r sand l e n s e s

s e p a r a t e d by d o l o m i t e beds.

The a v e r a g e t h i c k n e s s of t h e pay zone

i s 30 f e e t , p o r o s i t y a v e r a g e s 16.8 p e r c e n t , and p e r m e a b i l i t y a v e r a g e s

100 m i l l i d a r c i e s . The p r o d u c t i v e l i m i t s of t h e Minnelusa r e s e r v o i r a r e d e f i n e d by a n o i l - w a t e r c o n t a c t t o t h e southwest and a p o r o s i t y and p e r m e a b i l i t y l o s s updip t o t h e n o r t h e a s t .

Three Fox H i l l s Sandstone w e l l s s u p p l y

a l l of t h e f r e s h w a t e r f o r t h e i n j e c t i o n p r o j e c t .

A s of December, 1973,

8 11,402,284 b a r r e l s (4.789 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d through 11 w e l l s .

A t t h e end of 1976, 8 of t h e s e w e l l s were s t i l l

a c t i v e l y i n j e c t i n g , b u t b i a n n u a l i n j e c t i o n t o t a l s have n o t been r e p o r t e d s i n c e 1973. Casing Record:

I n j e c t i o n W e l l # 1 6 ~ ,T47N-R69W-7 dcb, D i l l i n g e r Ranch F i e l d , D i l l i n g e r Ranch U n i t , T o t a l Depth = 9352 f e e t .

Casing S i z e

Wt.

(#/ft)

8-518"

24

4-1/2"

10.5,11.6

Hole S i z e

S e t t i n g Depth

12-1/4"

365 '

150 s a c k s

9360'

300 s a c k s

7-7 18"

Cement

Donkey Creek F i e l d (14,460,631 b b l s o i l , 3,104,638 MCF g a s ; 1953-79) Dakota "A" U n i t Donkey Creek F i e l d i s l o c a t e d i n Townships 49 and 50 North, Range 68 West, Crook County.

The f i e l d was d i s c o v e r e d i n 1953, and produces

from t h e Dakota sand.

The Dakota "A" U n i t p a r t i c i p a t i n g a r e a i n c l u d e s

835 a c r e s of f e d e r a l and p r i v a t e l a n d . The w a t e r i n j e c t i o n p r o j e c t s t a r t e d i n 1973, w i t h f o u r i n j e c t o r s s u p p l i e d by Minnelusa Formation w a t e r produced i n a nearby f i e l d . The c u m u l a t i v e volume of w a t e r i n j e c t e d through December, 1979, w a s

8 3,989,538 b a r r e l s (1.6756 x 1 0 g a l l o n s ) .

Average i n j e c t i o n p r e s s u r e s

used i n t h e Dakota w a t e r f l o o d have ranged from 50 t o 1,500 pounds p e r s q u a r e i n c h ( p s i ) a t t h e wellhead.

Casing Record:

I n j e c t i o n W e l l #W-1, T50N-R68W-32 c a , Donkey Creek F i e l d , Dakota "Ar' U n i t , T o t a l Depth = 6299 f e e t .

Casing S i z e

Wt.

Amount

Grade

32.75

210 '

H-40

Surf a c e

23

830'

N-80

Injection

7"

1650'

5-55

Injection

7l'

3806 '

5-55

Injection

10-3/4" 7"

(#/ft)

Purpose

Burrows "B" U n i t The Burrows "B" U n i t of Donkey Creek F i e l d i s l o c a t e d i n Township 49 North, Range 68 West, Crook County.

A s a l t w a t e r d i s p o s a l system,

which s t a r t e d i n 1966, a t t h e Burrows "B"

U n i t , c o n s i s t s of two

i n j e c t i o n w e l l s c o m p l e t e d . i n t h e Dakota sand.

One of t h e w e l l s was

s t i l l a c t i v e i n December, 1979, when t h e cumulative volume of b r i n e

7 i n j e c t e d d u r i n g t h e p r o j e c t s t o o d a t 2,222,607 b a r r e l s (9.3349 x 1 0 gallons).

Average i n j e c t i o n p r e s s u r e s have ranged from 0 t o 1,320 p s i .

South Donkey Creek F i e l d (582,546 b b l s o i l ; 1957-79) Koch U n i t I n 1975, a s a l t w a t e r d i s p o s a l system s i m i l a r t o t h a t i n t h e Burrow " B " U n i t , b e g a n o p e r a t i n g i n t h e Koch U n i t of South Donkey Creek Field.

The s i n g l e w e l l system i s completed i n t h e Dakota sand.

Cumulative i n j e c t i o n through t h e end of 1979, was 120,816 b a r r e l s (5,074,272 g a l l o n s ) of produced b r i n e from producing o i l w e l l s a t Donkey Creek F i e l d .

Dugout Creek F i e l d (No production d a t a a v a i l a b l e ) The Dugout Creek o i l f i e l d was i n i t i a l l y developed i n 1953, following t h e discovery of o i l i n t h e Shannon sand.

The f i e l d i s

l o c a t e d i n t h e s o u t h e a s t c o r n e r of Johnson County i n Gection 1 8 , Township 42 North, Bange 78 West, and S e c t i o n s 12, 1 3 , 1 4 , and 17 of Township 42 North, Bange 79 West.

The Dugout Creek r e s e r v o i r i n c l u d e s

1,010 a c r e s w i t h an average pay t h i c k n e s s of 17 f e e t .

It i s bounded

on t h e s o u t h by an east-west t r e n d i n g f a u l t , on t h e west by a d e c r e a s e i n t h e p e r m e a b i l i t y of t h e Shannon sand and on t h e n o r t h by t h e watero i l contact.

The s t r u c t u r e w i t h i n t h e a r e a d i p s s t e e p l y t o t h e north-

e a s t and t h e r e a r e a number of s m a l l accumulations of gas trapped by transverse f a u l t s a t varying s t r u c t u r a l elevations.

Faults divide the

r e s e r v o i r i n t o f i v e d i s t i n c t b l o c k s , f o u r of which have s m a l l gas caps. A 1 1 of t h e f a u l t b l o c k s a r e u t i l i z e d i n t h e water i n j e c t i o n p r o j e c t .

The Shannon Sandstone i s a f r i a b l e , l i g h t g r a y , g l a u c o n i t i c sand w i t h a p o r o s i t y of 25 p e r c e n t and an e s t i m a t e d i n t e r s t i t i a l water c o n t e n t of 21 p e r c e n t . E s t i m a t e s of o i l o r i g i n a l l y i n p l a c e were 22.7 m i l l i o n b a r r e l s . The primary recovery mechanism of t h e Shannon sand was s o l u t i o n gas d r i v e a i d e d by t h e expansion of a s m a l l accumulation of updip g a s , g r a v i t y d r a i n a g e and t h e i n f l u x of water from t h e n o r t h and e a s t . Secondary o i l recovery began i n 1963 and was expanded over t h e n e x t 9 y e a r s t o i n c l u d e 26 water i n j e c t i o n w e l l s of which 10 were s t i l l a c t i v e l y i n j e c t i n g a s of August, 1979. (1.3115 x 10'

A t o t a l of 31,227,064 b a r r e l s

g a l l o n s ) had been i n j e c t e d up t o t h a t p o i n t .

Casing Record:

I n j e c t i o n W e l l #A733, T43N-R80W-33 c c b , Dugout Creek F i e l d , Shannon U n i t , T o t a l Depth = 2265 f e e t .

Casing S i z e

Wt.

(#/ft)

10-3/4" 7"

Depth S e t

Cement

Purpose

32

228'

200 s a c k s

Surface

23

2265'

200 s a c k s

Injection

Dutch F i e l d (639,134 b b l s o i l , 45,237 MCF g a s ; 1975-79) Record U n i t The o n l y i n j e c t i o n w e l l a t t h e Record U n i t of Dutch F i e l d i s a s a l t w a t e r d i s p o s a l w e l l , completed i n t h e Minnelusa Formation a t a d e p t h of 9,056 f e e t .

The w e l l , l o c a t e d i n S e c t i o n 31, Township 5 1

North, Range 70 West, Campbell County, was p u t i n t o o p e r a t i o n i n 1977. By December, 1979, 240,070 b a r r e l s (1.0082 x LO

7

g a l l o n s ) of produced

s a l t water had been i n j e c t e d d u r i n g t h e s y s t e m ' s d u r a t i o n .

Average

i n j e c t i o n p r e s s u r e s have ranged from 750 t o 1 , 2 5 0 p s i .

D u v a l l Ranch F i e l d (9,442,981 b b l s o i l ; 1964-79) Minnelusa U n i t The Minnelusa U n i t of D u v a l l Ranch F i e l d i s s i t u a t e d on t h e e a s t e r n s h e l f of t h e Powder R i v e r Basin approximately 20 m i l e s southeast of G i l l e t t e .

O i l was d i s c o v e r e d i n t h e upper Minnelusa Formation

i n 1964. The Minnelusa r e s e r v o i r i s a s t r a t i g r a p h i c t r a p bounded by a n o i l - w a t e r c o n t a c t t o t h e w e s t and a deep c h a n n e l of Opeche S h a l e d m g the eastern flank.

The r e s e r v o i r o c c u r s a t a d e p t h of a b o u t 8,200

f e e t i n t h e area and t h e primary producing mechanism i s a s o l u t i o n g a s d r i v e w i t h a s l i g h t e f f e c t from edge w a t e r expansion. pay zone d i p s t o t h e west-southwest a t n e a r l y 2'.

The t o p of t h e

Average p o r o s i t y and

p e r m e a b i l i t y are 1 7 p e r c e n t and 88.8 m i l l i d a r c i e s , r e s p e c t i v e l y .

Water i n j e c t i o n a t Duvall Ranch F i e l d began i n 1971, and eleven i n j e c t i o n wells a r e currently active.

December, 1979, d a t a i n d i c a t e

9 t h a t 26,805,977 b a r r e l s (1.1259 x 10 g a l l o n s ) of Fox H i l l s Sandstone water h a s been i n j e c t e d i n t o t h e upper Minnelusa r e s e r v o i r .

Casing Record:

I n j e c t i o n Well #8-2, T49N-R69W-14 db, Duvall Ranch F i e l d , Minnelusa Unit, T o t a l Depth = 8311 f e e t .

Casing Size

Wt. (alft)

Hole S i z e

Depth S e t

Cement

9-5 18''

32.3

13-314"

319 '

320 sacks

Surface

5-1/2"

15.5,17

8-314"

8311'

500 sacks

Injection

Purpose

Elk Basin F i e l d (401,633,653 b b l s o i l , 291,294,260 MCF gas; 1915-79) Elk Basin F i e l d i s l o c a t e d a t t h e n o r t h end of t h e Bighorn Basin i n Townships 57 and 58 North, Ranges 99 and 100 West, Park County, Wyoming, and Township 9 South, Range 23 E a s t , Carbon County, Montana. O i l was f i r s t discovered a t Elk Basin i n 1915, when a w e l l was

completed i n t h e f i r s t F r o n t i e r ( T o r c h l i g h t ) sand.

Subsequent d i s c o v e r i e s

were made i n t h e second F r o n t i e r (Peay) sand, t h e Cloverly Formation, t h e Tensleep Sandstone, t h e Madison Limestone, t h e J e f f e r s o n Formation, and t h e Bighorn Dolomite.

Hydrocarbons a r e s t r u c t u r a l l y entrapped

w i t h i n a broad, double-crested,

asymmetrical, northwest-southeast

trending a n t i c l i n e with a steeply sloping northeast side. Madison Unit The Madison r e s e r v o i r of Elk Basin F i e l d covers an a r e a of 5,097 a c r e s w i t h an average pay zone t h i c k n e s s of 150 f e e t .

O i l was discovered

i n t h e Madison Limestone i n 1946, when a w e l l on t h e c r e s t of t h e a n t i c l i n e was deepened t o 4,680 f e e t .

A p i l o t waterflood p r o j e c t began i n 1960, and was expanded t o a f u l l s c a l e f l o o d one year l a t e r .

The p r o j e c t was i n i t i a l l y a p r e s s u r e

maintenance o p e r a t i o n which was converted t o a secondary recovery operation.

Produced water from t h e Madison Limestone, Bighorn Dolomite,

F r o n t i e r and Embar (Phosphoria) formations, and Tensleep Sandstone and f r e s h water from t h e Clarks Fork River a r e i n j e c t e d through 37 a c t i v e

w e l l s , 1 4 of which a r e d u a l annulus-tubing i n j e c t o r s .

Ten o t h e r i n j e c -

t i o n w e l l s have been temporarily o r permanently s h u t - i n ,

A s of December,

8 1979, 221,991,787 b a r r e l s (9.3237 x 10 g a l l o n s ) of water had been i n j e c t e d i n t o t h e Madison r e s e r v o i r .

Originally, the injection w e l l configuration

was a p e r i p h e r a l p a t t e r n , b u t i t was converted t o a l i n e d r i v e p a t t e r n .

Case Record:

Casing S i z e 10-314"

7"

I n j e c t i o n Well #166, T58N-R99W-30 add, Elk Basin F i e l d , Madison U n i t , T o t a l Depth = 6835 f e e t . Wt.

(#/ft)

Depth S e t

Hole S i z e

Cement

32.75

2061'

15"

Previously s e t

20,23

5815'

9"

Previously s e t

F r o n t i e r Unit The Elk Basin F r o n t i e r Unit produces from two sand horizons i n t h e upper F r o n t i e r Formation a t depths between 1,000 and 1,700 f e e t . u n i t i s l o c a t e d i n Township 58 North, Ranges 99 and 100 West.

The

Water

i n j e c t i o n i n t o t h e F r o n t i e r sands s t a r t e d i n June, 1966, through 3 wells.

The waterflood p r o j e c t followed a period of gas i n j e c t i o n s i n

t h e F r o n t i e r r e s e r v o i r s and was undertaken a s a p i l o t p r o j e c t t o d e t e r mine whether o r n o t f u t u r e waterflooding of t h e r e s e r v o i r s would be successful.

Four of t h e 10 a c t i v e i n j e c t i n g w e l l s ( s t a t u s a s of 12/79)

a r e d u a l i n j e c t o r s which i n j e c t i n t o t h e upper sand through t h e w e l l c a s i n g and i n t o t h e lower sand through tubing.

Current O i l and Gas Commission d a t a i n d i c a t e t h a t 40,539,399 8 b a r r e l s (1.6965 x 10 g a l l o n s ) of Madison Limestone water have been i n j e c t e d between 1966 and 1980.

Embar-Tensleep Unit A l l of t h e i n j e c t i o n w e l l s of t h e Embar-Tensleep Unit of Elk Basin

F i e l d have been permanently shut-in f o r a t l e a s t two y e a r s and a r e no longer r e p o r t e d i n t h e annual O i l and Gas Commission s t a t i s t i c s compilation.

South Elk Basin F i e l d (15,982,216 b b l s o i l , 32,735,230 MCF gas; 1945-79) Peay/Tensleep Unit South Elk Basin F i e l d was discovered i n 1945, when a w e l l was completed i n t h e Tensleep Sandstone between 6,975 and 7,135 f e e t .

The

f i e l d i s l o c a t e d i n Township 57 North, Range 99 West, Park County. The Tensleep Unit covers 540 a c r e s of f e d e r a l and p r i v a t e land and governs production and i n j e c t i o n i n t h e underlying Tensleep and Peay r e s e r v o i r s .

The Tensleep r e s e r v o i r has an a r e a of 520 a c r e s w i t h

an average pay zone t h i c k n e s s of about 75 f e e t .

Data on t h e e x t e n t of

t h e Upper Cretaceous Peay r e s e r v o i r a t South Elk Basin were u n a v a i l a b l e . The Pennsylvanian Tensleep Sandstone i s described a s a s e r i e s of 7 marine sandstone beds s e p a r a t e d by impermeable sandy dolomite s t r i n g e r s . Average p o r o s i t y and p e r m e a b i l i t y of t h e Tensleep a r e 14.2 p e r c e n t and 190 m i l l i d a r c i e s , r e s p e c t i v e l y . S t r u c t u r a l l y , South Elk Basin i s a s m a l l , asymmetrical, northwests o u t h e a s t t r e n d i n g a n t i c l i n e w i t h a c l o s u r e which i n c l u d e s t h e e n t i r e a r e a of t h e Tensleep r e s e r v o i r .

F l u i d withdrawals have exceeded

formation water i n f l u x s i n c e 1955, r e s u l t i n g i n a s t e a d y d e c l i n e of

r e s e r v o i r p r e s s u r e and p r o d u c t i v i t y .

I n 1962, w a t e r i n j e c t i o n i n t o t h e

Tensleep began w i t h t h e purpose of augmenting t h e l i m i t e d n a t u r a l w a t e r d r i v e p r e s s u r e of t h e r e s e r v o i r .

S i x of 7 i n j e c t o r s a r e c u r r e n t l y

9 a c t i v e (December, 1979) and 46,628,477 b a r r e l s (1.9584 x 1 0 g a l l o n s ) of produced T e n s l e e p w a t e r have been i n j e c t e d i n t o t h e Tensleep and Peay s a n d s .

The s h u t - i n w e l l i s a d u a l Tensleep-Peay i n j e c t i o n w e l l .

Casing Record:

I n j e c t i o n W e l l #45, T57N-R99W-17 d c , South E l k Basin F i e l d , Tensleep U n i t , T o t a l Depth = 7330 f e e t .

Casing Size

Wt. ( w t )

Depth S e t

Hole S i z e

9-5 / 8"

36

292'

12-1/4"

225 s a c k s

23,26

7330'

8-3/4"

1200 s a c k s

7"

Cement

Purpose Surface I n je c t i o n

Empire F i e l d (534,588 b b l s o i l , 199,331 MCF g a s ; 1974-79) Teapot U n i t A s i n g l e w e l l s a l t w a t e r d i s p o s a l system was s t a r t e d i n 1975, a t

t h e Teapot U n i t of Empire F i d d , u n d e r t h e o p e r a t i o n of Texaco, I n c . The i n j e c t i o n w e l l i s l o c a t e d i n S e c t i o n 22, Township 47 North, Range 67 West, Johnson County, and i s p e r f o r a t e d i n t h e Teapot Sandstone a t a d e p t h of 7,238 f e e t .

A s of December, 1979, a c u m u l a t i v e volume of

7 446,601 b a r r e l s (1.8757 x 1 0 g a l l o n s ) of b r i n e had been i n j e c t e d a t a v e r a g e p r e s s u r e s between 0 and 1,950 p s i .

Fence Creek F i e l d (1,447,444 b b l s o i l , 309,045 MCF g a s ; 1968-79) Muddy Sand U n i t Fence Creek o i l f i e l d i s l o c a t e d i n Townships 57 and 58 North, Range 76 West, i n S h e r i d a n and Campbell Counties.

The f i e l d was

d i s c o v e r e d i n 1968, when a w e l l was completed i n t h e Muddy Sandstone.

The Muddy Unit p a r t i c i p a t i n g a r e a i n c l u d e s 1,550 a c r e s of f e d e r a l and p r i v a t e land. The Muddy r e s e r v o i r covers 967 a c r e s and has an average pay zone t h i c k n e s s of 10 f e e t .

Average p o r o s i t y and p e r m e a b i l i t y a r e 16

p e r c e n t and 70 m i l l i d a r c i e s ( a i r p e r m e a b i l i t y ) , r e s p e c t i v e l y .

Hydro-

carbon entrapment t o t h e e a s t , n o r t h , and northwest r e s u l t s from an upstructure permeability b a r r i e r .

To t h e southwest, production i s

l i m i t e d by an apparent oil-water c o n t a c t . Water i n j e c t i o n i n t o t h e Muddy r e s e r v o i r s t a r t e d i n 1974, u t i l i z i n g f r e s h water from t h e Fox H i l l s Sandstone and produced Muddy Sandstone water.

The 4 i n j e c t i o n w e l l s had been temporarily shut-in a s of t h e

end of 1979, w i t h a cumulative i n j e c t e d water volume of 1,077,085 7 b a r r e l s (4.5238 x 10 g a l l o n s ) .

Casing Record:

I n j e c t i o n Well #A332, T58N-R76W-32 abb, Fence Creek F i e l d , Muddy Sand U n i t , T o t a l Depth = 7580 f e e t .

Casing Size

Wt. (a/ft>

Hole S i z e

Depth S e t

Cement

8-5 / 8"

24

12-1/4l1

255'

-

5-1/2"

15.5,17

7-7/8"

7588'

150 sacks

Purpose Surf a c e Injection

F i d d l e r Creek F i e l d (7,026,076 b b l s o i l ; 1948-79) West F i d d l e r Creek Unit

The West F i d d l e r Creek Unit i n c l u d e s 7,557.22 a c r e s of f e d e r a l , s t a t e , acquired and p a t e n t e d land i n t h e southern h a l f of Township 46 North, Range 65 West, and s o u t h e a s t q u a r t e r of Township 46 North, Range 66 West, Weston County.

O i l was discovered a t F i d d l e r Creek F i e l d i n

1948, when a w e l l i n t h e East F i d d l e r Creek Unit a r e a was completed i n t h e Newcastle Sandstone.

The Newcastle Sandstone, o f t e n c a l l e d t h e Muddy Sandstone, i s a h i g h l y v a r i a b l e zone of discontinuous beds of cross-bedded sandstone, s h a l e , sandy s h a l e , carbonaceous s h a l e , impure l i g n i t e and b e n t o n i t e . The pay sand of t h e Newcastle i s medium- t o fine-grained, w i t h s h a l e y s t r e a k s and carbonaceous m a t e r i a l .

Overlying t h e Newcastle sand i s a

cap of s h a l e and sandy s h a l e 300 f e e t t h i c k , known a s t h e Mowry Shale. Underlying t h e Newcastle i s t h e S k u l l Creek Shale. The West F i d d l e r Creek r e s e r v o i r covers 5,207 a c r e s and has an average pay t h i c k n e s s of 5.8 f e e t .

The average p o r o s i t y and perme-

a b i l i t y of t h e Newcastle sand i n t h i s a r e a a r e 20 percent and 1 t o 18 millidarcies, respectively. The i n i t i a l mechanism of production from t h e r e s e r v o i r was a s o l u t i o n gas d r i v e . u n i t i n 1960.

Water i n j e c t i o n began i n t h e e a s t e r n p a r t of t h e

The i n j e c t i o n p a t t e r n i s a modified l i n e d r i v e p a t t e r n ,

due t o t h e meandering channel type sand d e p o s i t s t h a t a r e n o t s u i t e d f o r conventional l i n e d r i v e i n j e c t i o n .

A s of December, 1979, 66 of

t h e 76 i n j e c t i o n w e l l s i n t h e West F i d d l e r Creek Unit had been shut-in. The remaining t e n w e l l s were a c t i v e l y i n j e c t i n g .

The cumulative amount

of water i n j e c t e d i n t o t h e Newcastle from t h e Madison a q u i f e r s i n c e 9 1960 was 88,404,124 b a r r e l s (3.713 x 10 g a l l o n s ) a t t h e end of 1979. Casing Record:

I n j e c t i o n W e l l 8130, T46N-R65W-28 c a , West F i d d l e r Creek U n i t , T o t a l Depth = 5260 f e e t .

Casing S i z e

Wt.

8-5/8"

(#/ft) 24

Depth S e t (MD)

Hole S i z e

Cement

207.85'

12-114"

150 sacks regular

5251.46'

7-7/8"

130 sacks (50-50 pozmix)

E a s t F i d d l e r Creek U n i t (11,029,418 b b l s o i l ; 1948-79) The E a s t F i d d l e r Creek U n i t c o v e r s a n a r e a of 2,799.79 a c r e s of f e d e r a l , s t a t e , and p r i v a t e f e e l a n d .

The a r e a was u n i t i z e d i n 1955,

seven y e a r s a f t e r t h e f i r s t o i l w e l l had been completed i n t h e Newcastle sand.

The d e p t h t o t h e Newcastle Sandstone i n t h e a r e a of

c e n t r a l Weston County i s g e n e r a l l y between 4,500 and 4,550 f e e t w i t h an a v e r a g e f o r m a t i o n t h i c k n e s s of 50 f e e t .

The Newcastle c o n s i s t s of a

s u c c e s s i o n of t h i n beds of s a n d s t o n e , s i l t s t o n e , and s h a l e .

The pay

zone i s a f i n e - t o medium-grained sand w i t h s h a l e i n t e r c a l a t i o n s and carbonaceous m a t e r i a l .

The a v e r a g e p o r o s i t y and p e r m e a b i l i t y of t h e

pay zone a r e 18.6 p e r c e n t and 3 t o 6 m i l l i d a r c i e s , r e s p e c t i v e l y . Water was f i r s t i n j e c t e d i n t o t h e Newcastle sand i n 1955, and h a s expanded t o a p e r i p h e r a l i n j e c t i o n system of 80 i n j e c t o r s , t e n of which were a c t i v e i n December, 1979.

The remainder of t h e i n j e c t i o n

w e l l s have been t e m p o r a r i l y o r permanently s h u t - i n .

Water f o r t h e

i n j e c t i o n p r o j e c t i s provided by a Madison Limestone s u p p l y w e l l which i n i t i a l l y produced

11,000 b a r r e l s p e r day.

The t e m p e r a t u r e of t h e

Madison w a t e r i s r e p o r t e d t o b e 135OF, making i t i d e a l f o r f l o o d i n g t h e c o o l e r Newcastle Sandstone.

The c u m u l a t i v e t o t a l i n j e c t e d through t h e

9 80 w e l l s between 1955 and 1980, was 71,859,156 b a r r e l s (3.0181 x 10 g a l l o n s ) of w a t e r .

Casing Record:

I n j e c t i o n W e l l #122, T46N-R65W-13 ddd, E a s t F i d d l e r Creek U n i t , T o t a l Depth = 4590 f e e t . Make

Amount ( f t )

32.75

H-40

160.48 Guide w i t h float collar

Surface

23

5-55

1661.5 Guide w i t h float collar

Injection

7"

20

H-40

2856.62

Injection

7"

23

5-55

31.76

Injection

Casing S i z e 10-3/4"

Wt.

(#/ft)

Purpose

Casing Record:

I n j e c t i o n Well # 1 7 5 ~ ,T46N-R65W-23 cdc, East F i d d l e r Creek U n i t , T o t a l Depth = 4871 f e e t .

.

Casing Size

Wt (#/ft)

Make

Amount ( f t )

8-5 / 8"

24

J-55

100.5

9.5

5-55

4-1/2"

Purpose

Cement

Casing landed a t 112 f t KB

4871

3rd c a s i n g landed a t 4869 f t KB

60 s a c k s 125 s a c k s

Fourbear F i e l d (21,073,431 b b l s o i l , 6,815 MCF g a s ; 1928-79) North Fourbear U n i t The North Fourbear U n i t , l o c a t e d i n Township 48 North, Range 103 West, P a r k County, h a s , s i n c e 1972, been t h e s i t e of a s a l t w a t e r

d i s p o s a l system.

Water produced w i t h o i l from w e l l s a t Fourbear F i e l d

i s i n j e c t e d i n t o t h e Darwin Sandstone and Madison Limestone a t d e p t h s between 3,200 and 3,750 f e e t .

Four w e l l s were a c t i v e l y i n j e c t i n g t h e

produced b r i n e as of December, 1979, w i t h one w e l l under c o n s t r u c t i o n . Cumulative i n j e c t i o n t o t h a t p o i n t was 1.6115 x LO

8

9 b a r r e l s (6.7684 x 1 0

g a l l o n s ) of s a l t w a t e r . Casing Record:

S a l t Water D i s p o s a l W e l l , T48N-R103W-20, North Fourbear Unit.

Fourbear F i e l d ,

Casing S i z e

Depth S e t

Cement

13-318"

252 '

500 s a c k s

9-518"

3562'

420 s a c k s

Fourbear U n i t The i n i t i a l y e a r of o p e r a t i o n was 1976, f o r t h e s i n g l e w e l l s a l t w a t e r d i s p o s a l system a t t h e Fourbear U n i t of Fourbear F i e l d .

The w e l l

i s l o c a t e d i n S e c t i o n 3 , Township 47 North, Range 103 West, P a r k County.

8 As of December, 1979, 4,576,608 barrels (1.9222 x 10 gallons) of produced brine had been injected to the Dinwoody and Phosphoria formations since the project started. Frannie Field (95,497,671 bbls oil, 264,290 MCF gas; 1928-79) Phosphoria/Tensleep Unit The Frannie Field was discovered in 1928, with production of oil from a well completed in the Phosphoria and Tensleep formations. The Tensleep Sandstone in the Frannie Field area was deposited conformably over the Arnsden Formation during early and middle Pennsylvanian time. The Tensleep is composed of fine- to medium-grained, cross-bedded, well sorted, non-marinesandstone with interbedded dolomite. As a result of interbedding and facies transitions, there is a significant variation in porosity and permeability. Upper Tensleep zones tend to have less dolomite than lower zones and thus have higher porosity and permeability. The Phosphoria Formation was deposited during the middle Permian age. It is predominantly a crystalline dolomite which grades into dolomitic sandstones that have porosities and permeabilities similar to the Tensleep.

In the Phosphoria/Tensleep reservoir, the average porosity

and permeability of the productive zones are 16.3 percent and 223 millidarcies, respectively. Structually, the Phosphoria/Tensleep reservoir is situated within a northwest-southeast trending anticline, the flanks of which dip approximately 13' to the southwest and 40' to the northeast. Water pressure gradients in the area are from east to west.

The major influx

of water has been through a saddle between the Frannie structure and the Sage Creek anticline to the southeast. The primary mechanisms of

p r o d u c t i o n i n F r a n n i e F i e l d are f l u i d expansion, s o l u t i o n g a s d r i v e , g r a v i t y d r a i n a g e , and w a t e r i n f l u x d r i v e . The Phosphoria/Tensleep U n i t p a r t i c i p a t i n g area c o v e r s 2,002 a c r e s o f f e d e r a l , s t a t e , and p r i v a t e l a n d . a r e l o c a t e d i n t h e s t a t e of Montana.

Of t h a t a r e a , 114 a c r e s

Water i n j e c t i o n s t a r t e d i n 1970,

and by J a n u a r y , 1980, i n c l u d e d 32 w e l l s , 30 of which were s t i l l a c t i v e l y injecting.

F o u r t e e n of t h e a c t i v e w e l l s a r e d u a l i n j e c t o r s .

A s of

9 December, 1979, 119,970,367 b a r r e l s (5.0388 x 1 0 g a l l o n s ) had been i n j e c t e d i n t o t h e P h o s p h o r i a / ~ e n s l e e pr e s e r v o i r .

Data on c a s i n g

s c h e d u l e s a t F r a n n i e F i e l d were u n a v a i l a b l e a t t h e t i m e Of t h i s w r i t i n g . Garland F i e l d (137,347,757 b b l s o i l , 131,013,001 MCF g a s ; 1906-79) Harriman U n i t Garland F i e l d was d i s c o v e r e d i n 1906, when o i l was f i r s t produced from t h e Peay sand of t h e F r a n t i e r Formation.

The f i e l d i s l o c a t e d i n

Townships 55 and 56 North, Ranges 97 and 98 West, P a r k and Big Horn counties. The Harriman U n i t of Garland F i e l d , o p e r a t e d by CENEX, I n c . , governs p r o d u c t i o n from t h e Morrison and C l o v e r l y formations. g a s was d i s c o v e r e d i n b o t h f o r m a t i o n s d u r i n g t h e 1 9 2 0 ' s .

Natural

Three a c t i v e

(December, 1979 s t a t u s ) w a t e r i n j e c t i o n w e l l s i n t h e Morrison and 7 C l o v e r l y r e s e r v o i r s have i n j e c t e d 2,145,791 b a r r e l s (9.0123 x 10 g a l l o n s ) of produced Tensleep w a t e r s i n c e t h e w a t e r f l o o d p r o j e c t began i n 1971.

Average p o r o s i t y and p e r m e a b i l i t y i n t h e ~ o r r i s o n / ~ l o v e r l y

r e s e r v o i r are 15.5 p e r c e n t and 63.7 m i l l i d a r c i e s , r e s p e c t i v e l y . The Harriman U n i t i s a l s o t h e s i t e of a one w e l l s a l t water d i s p o s a l system, which began o p e r a t i o n d u r i n g 1970.

The w e l l i s

completed i n t h e Tensleep Sandstone a t a d e p t h of 4,770 f e e t .

A

8 c u m u l a t i v e volume o f 2,972,726 b a r r e l s (1.2485 x 1 0 g a l l o n s ) of produced b r i n e from w e l l s a t Garland F i e l d had been r e - i n j e c t e d a s of December, 1979.

Average i n j e c t i o n p r e s s u r e s have ranged between 20

and 265 p s i .

Casing Record:

I n j e c t i o n W e l l #19, T56N-R98W-ll cbd, Garland F i e l d , Harriman U n i t , T o t a l Depth = 3702 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

8-5/8"

24

12-1/4"

200 '

250 s a c k s

5-1/2"

14

7-7 /8"

3702 '

300 s a c k s

Casing Record:

S a l t Water D i s p o s a l Well # l o , T56N-R98W-11 Garland F i e l d , Harriman U n i t .

Casing S i z e

Wt.

7"

(#/ft)

ccd,

Depth S e t

Make

Cement

4912'

5-55

150 s a c k s

23

Kinney-Coastal U n i t The Kinney-Coastal U n i t p a r t i c i p a t i n g a r e a i n c l u d e s 1 , 6 4 6 a c r e s of t h e T e n s l e e p U n i t and 1 , 3 8 8 a c r e s of t h e Embar U n i t i n Township 56 North, Ranges 97 and 98 Mest, P a r k and Big Horn c o u n t i e s . The Tensleep r e s e r v o i r h a s a p r o d u c t i v e a r e a of 1,508 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of a b o u t 59 f e e t .

I n order t o maintain

p r e s s u r e w i t h i n t h e r e s e r v o i r , a water i n j e c t i o n p r o j e c t . w a s u n d e r t a k e n i n 1958, by Marathon O i l Company.

Produced w a t e r from t h e Madison

Limestone of t h e Garland F i e l d a r e a i s used f o r t h e p r o j e c t . I n December, 1966, a s i m i l a r p r o j e c t was s t a r t e d i n t h e Embar (Phosphoria) r e s e r v o i r u s i n g produced w a t e r from t h e Embar Formation and T e n s l e e p Sandstone.

C u r r e n t l y (December, 1 9 7 9 ) , t h e r e a r e 27 i n j e c t i o n

w e l l s involved i n t h e Kinney-Coastal Unit waterflood of t h e Tensleep and Embar r e s e r v o i r s .

Twenty-four of t h e w e l l s a r e a c t i v e i n j e c t o r s ,

w i t h 12 being d u a l i n j e c t o r s .

Cumulative i n j e c t i o n and w e l l c a s i n g

d a t a f o r t h e Kinney-Coastal Unit were u n a v a i l a b l e a t t h e time of t h i s writing.

Average i n j e c t i o n p r e s s u r e s i n both p r o j e c t s range from a

minimum of 140 t o a maximum of 1,370 p s i . Community #3 Unit A s a l t water d i s p o s a l system, completed i n t h e Madison Limestone,

was put i n t o o p e r a t i o n i n 1977, a t t h e Community #3 Unit of Garland Field.

The s i n g l e w e l l system i s l o c a t e d i n Section 32, Township 56

North, Range 97 West, Park County.

A s of June, 1980, 3,315,193

8 b a r r e l s (1.3924 x 10 g a l l o n s ) of produced s a l t water had been i n j e c t e d t o t h e Madison Limestone a t average i n j e c t i o n p r e s s u r e s between 120 and 1,680 p s i .

Allen-Jones Unit The Allen-Jones Unit s a l t water d i s p o s a l system was s h u t - i n during 1978, a f t e r t h r e e y e a r s of b r i n e i n j e c t i o n through two w e l l s completed i n t h e Madison Limestone.

A t t h e time t h a t t h e system was s h u t - i n ,

a

8 cumulative volume of 20,330,991 b a r r e l s (8.539 x 10 g a l l o n s ) of b r i n e had been i n j e c t e d .

Willey Unit The s i n g l e w e l l s a l t water d i s p o s a l system a t t h e Willey Unit of Garland F i e l d i s operated by Marathon O i l Company. produced b r i n e began a t w e l l #3 i n 1979.

I n j e c t i o n of

The d i s p o s a l w e l l , l o c a t e d

i n Lot 59, Township 56 North, Range 97 West, Big Horn County, i s

p e r f o r a t e d a t a depth of 4,407 f e e t i n t h e Madison Limestone.

Cumulative

i n j e c t i o n and average p r e s s u r e d a t a were n o t y e t a v a i l a b l e a t t h e time of t h i s w r i t i n g .

Garland Unit The Garland Unit i s t h e s i t e of a n a t u r a l gas s t o r a g e p r o j e c t t h a t began o p e r a t i o n i n 1964.

The p r o j e c t i n c l u d e s t h r e e gas i n j e c t i o n

w e l l s completed i n t h e CloverLy Formation.

D e t a i l e d d a t a on t h e p r o j e c t

were n o t a v a i l a b l e from O i l and Gas Commission f i l e s . Gas Draw F i e l d (23,359,314 b b l s o i l , 2,047,685 MCF gas; 1968-79) Gas Draw F i e l d i s l o c a t e d on t h e g e n t l y dipping e a s t f l a n k of t h e Powder River Basin, approximately 20 m i l e s n o r t h of G i l l e t t e .

The

f i e l d was developed on an 80-acre spacing p a t t e r n and covers about 7,463 a c r e s .

The main producing i n t e r v a l , designated t h e Gas Draw

sand, occurs j u s t below t h e t o p of t h e Muddy Sandstone.

The sand i s a

c l e a n , b a r sand w i t h average p o r o s i t y and p e r m e a b i l i t y of 20.2 percent and 188 m i l l i d a r c i e s , r e s p e c t i v e l y .

The average t h i c k n e s s of t h e pay

zone of t h e Gas Draw sand i s 8 f e e t . Gas Draw Unit The Gas Draw Unit covers 8,100 a c r e s of f e d e r a l , s t a t e , p r i v a t e , commutized, and unleased land i n Townships 53 and 54 North, Ranges 72 and 72 West, Campbell County.

Water i n j e c t i o n i n t o t h e Gas Draw sand of

t h e Muddy Sandstone s t a r t e d i n 1972.

Cumulative i n j e c t i o n through 16

w e l l s t o December, 1979, was 60,769,551 b a r r e l s (2.5523 x 109 g a l l o n s ) of f r e s h water from t h e Fox H i l l s Sandstone and Lance Formation and produced Muddy water.

F i f t e e n of t h e w e l l s a r e s t i l l a c t i v e l y i n j e c t i n g .

A l l i n j e c t i o n w e l l s were i n i t i a l l y t r e a t e d w i t h calcium c h l o r i d e t o prevent c l a y s w e l l i n g and damage t o t h e r e s e r v o i r . Casing Record:

Casing S i z e

I n j e c t i o n W e l l #34-5b, T53N-R72W-5 dca, Gas Draw F i e l d , Gas Draw Unit, T o t a l Depth = 7375 f e e t . ( m t )

Wt.

8-5 / 8"

24

5-1/2"

15.5,17

Hole S i z e

Depth S e t

Cement

12-114"

150 '

200 sacks

7-718"

7375'

300 sacks

Rogers Muddy Sand Unit The Rogers Muddy Sand Unit i s l o c a t e d i n Townships 54 and 55 North, Ranges 72 and 73 West and i s a northward e x t e n s i o n of t h e Gas Draw Field.

A t t h e s o u t h end of t h e Rogers Unit i s a neck of low perme-

a b i l i t y s t r a t a t h a t s e p a r a t e s t h e u n i t from t h e main f i e l d .

The

p r o d u c t i v e l i m i t s on t h e n o r t h , e a s t , and west a r e d e f i n e d by a pinchout of t h e Gas Draw sand.

The s t r a t i g r a p h y of t h e Rogers a r e a d i f f e r s from

t h a t of t h e main f i e l d i n t h a t i t i s u n d e r l a i n by a h i g h l y porous lower Muddy a q u i f e r of c o n s i d e r a b l e a r e a l e x t e n t . Water i n j e c t i o n i n t o t h e Muddy sand of t h e Rogers Unit began i n 1972, through 3 w e l l s .

Those 3 w e l l s remain a c t i v e (December, 1979

8 s t a t u s ) and have i n j e c t e d a t o t a l of 5,625,173 b a r r e l s (2.3626 x 10 g a l l o n s ) of water from t h e Fox H i l l s Sandstone and Lance Formation. Casing Record :

I n j e c t i o n Well #7-1, T55N-R72W-30 cb (cd) , Gas Draw F i e l d , Rogers Muddy Sand U n i t , T o t a l Depth = 7168 feet

.

Casing S i z e 8-5 / 8" 5-112"

Wt.

(#/ft) 24

15.5,17

Hole S i z e

Depth S e t

Cement

12-1/4"

300'

500 sacks (circulation)

7-7/8"

-

300 sacks

E a s t Gas Draw F i e l d (622,977 b b l s o i l , 116,778 MCF g a s ; 1975-79) Collins Unit A s i n g l e w e l l s a l t w a t e r d i s p o s a l system, o p e r a t e d by Marmik O i l Company, began i n j e c t i o n i n 1976.

The d i s p o s a l w e l l , l o c a t e d i n

S e c t i o n 1 2 , Township 53 North, Range 72 West, Campbell County, i s p e r f o r a t e d a t a d e p t h of 6,866 f e e t i n t h e Muddy Sandstone.

Cumulative

7 i n j e c t i o n through J u l y , 1979, t o t a l e d 275,305 b a r r e l s (1.1562 x 1 0 g a l l o n s ) of b r i n e from producing o i l w e l l s a t E a s t Gas Draw F i e l d . The maximum a v e r a g e i n j e c t i o n p r e s s u r e h a s been 200 p s i d u r i n g t h e project's lifetime.

Gibbs Ranch F i e l d (679,482 b b l s o i l , 9,418 MCF g a s ; 1970-79)

MWM S t a t e U n i t A s a l t w a t e r d i s p o s a l w e l l completed i n t h e Minnelusa Formation,

a t a d e p t h of 7,434 f e e t , w a s p u t i n t o o p e r a t i o n i n 1977.

The w e l l i s

l o c a t e d i n S e c t i o n 1 6 , Township 52 North, Range 69 West, Campbell County.

The c u m u l a t i v e volume of s a l t w a t e r i n j e c t e d a s of December,

1979, was 128,680 b a r r e l s (5,404,560 g a l l o n s ) . Lindstrom-Federal U n i t Another s a l t water d i s p o s a l system was c o n s t r u c t e d a t t h e LindstromF e d e r a l U n i t (T52N-R69W) i n 1978. i n t h e Minnelusa "C"

sand.

The s o l e d i s p o s a l w e l l i s p e r f o r a t e d

As of December, 1979, 27,207 b a r r e l s

(1,142,694 g a l l o n s ) of produced b r i n e had been i n j e c t e d s i n c e d i s p o s a l began.

Glenrock F i e l d (2,529,175 b b l s o i l , 158,215 MCF g a s ; 1949-79) M c N e i l Unit

The McNeil U n i t of Glenrock F i e l d i s l o c a t e d i n Township 33 North, Range 75 West, Converse County.

A one w e l l s a l t w a t e r d i s p o s a l system

began i n j e c t i n g produced b r i n e i n t o t h e Dakota and f i r s t Wall Creek s a n d s a t d e p t h s of 6,954 and 5,780 f e e t , r e s p e c t i v e l y . p e r f o r a t e d w e l l i s l o c a t e d i n S e c t i o n 4.

The d u a l l y

Cumulative i n j e c t i o n as of

7 December, 1979, was 45&,150 b a r r e l s (1.9242 x 1 0 g a l l o n s ) of produced s a l t wa-ter.

South Glenrock F i e l d (70,944,609 b b l s o i l , 30,303,976 MCF g a s ; 1950-79) South Glenrock F i e l d , l o c a t e d j u s t west of Big Muddy F i e l d and one-half m i l e s o u t h of Glenrock F i e l d , c o v e r s over 17,200 a c r e s i n Townships 32, 33, and 34 North, Ranges 75 and 76 West, Converse County. The d i s c o v e r y w e l l w a s completed i n 1950, i n t h e Dakota sand.

Shows of

o i l were l a t e r recorded i n t h e Muddy and Shannon s a n d s t o n e s .

The f i e l d

w a s d i v i d e d i n t o t h r e e b l o c k s and s e p a r a t e w a t e r f l o o d agreements were completed f o r each u n i t .

Block "A,"

c o v e r i n g 1,284 a c r e s of f e d e r a l ,

s t a t e , and p r i v a t e l a n d , was d i v i d e d i n t o t h e Muddy and Dakota u n i t s , b o t h of which are o p e r a t e d by A t l a n t i c R i c h f i e l d Company.

Block "By1'

10,874 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d , was d i v i d e d i n t o 3 u n i t s o p e r a t e d by C o n t i n e n t a l O i l Company, t h e upper Muddy, lower Muddy and t h e Dakota.

M and K O i l O p e r a t i o n s o p e r a t e s t h e Block "C"

lower

Muddy U n i t which i n c l u d e s 4,736 a c r e s of s t a t e and p r i v a t e l a n d . Block "A" Muddy U n i t The upper Muddy r e s e r v o i r of Block "A" an a v e r a g e pay zone t h i c k n e s s of 6 f e e t .

c o v e r s about 320 a c r e s w i t h

Average p o r o s i t y and

p e r m e a b i l i t y i n t h e upper Muddy throughout South Glenrock F i e l d a r e 20 p e r c e n t and 200 m i l l i d a r c i e s , r e s p e c t i v e l y . The primary mechanism of o i l p r o d u c t i o n i n t h e r e s e r v o i r i s by g a s expansion d r i v e and, s i n c e 1967, h a s been augmented by w a t e r injection.

x

lo8

Between 1967, and December, 1979, 4,113,185 b a r r e l s (1.7275

g a l l o n s ) were i n j e c t e d i n t o t h e upper Muddy "Af' r e s e r v o i r through

4 w e l l s , o n l y one of which was s t i l l a c t i v e .

Water f o r t h e i n j e c t i o n

p r o j e c t i s s u p p l i e d by a w e l l i n a n unknown a q u i f e r r e p o r t e d a s t h e "shallow sands."

Three of t h e i n j e c t i o n w e l l s , i n c l u d i n g t h e a c t i v e

w e l l , a r e dual injectors.

Block "A"

Dakota U n i t

The Dakota "A"

r e s e r v o i r encompasses 1 , 2 8 4 a c r e s w i t h a pay zone

t h i c k n e s s of 28 f e e t .

P o r o s i t y and p e r m e a b i l i t y a v e r a g e 1 4 p e r c e n t

and 75 m i l l i d a r c i e s , r e s p e c t i v e l y , i n t h e Dakota sand a c r o s s t h e e n t i r e South Glenrock F i e l d . Primary r e s e r v o i r energy was provided by a p a r t i a l w a t e r d r i v e and s o l u t i o n g a s d r i v e b e f o r e w a t e r i n j e c t i o n s t a r t e d i n 1967.

A s of

8 December, 1979, 18,345,759 b a r r e l s (7.7052 x 1 0 g a l l o n s ) of f r e s h

w a t e r from a w e l l i n a n unknown a q u i f e r c a l l e d t h e "shallow sands" had been i n j e c t e d i n t o t h e Dakota "A"

r e s e r v o i r through 9 w e l l s .

Seven

of t h e i n j e c t o r s a r e s t i l l a c t i v e and two of t h o s e w e l l s a r e d u a l injectors.

Maximum i n j e c t i o n p r e s s u r e s f o r b o t h u n i t s i n Block "A"

have been 2,300 p s i .

Block "B"

Upper Muddy U n i t

The Block "B" Upper Muddy U n i t i s l o c a t e d i n Township 33 North, Range 75 West, Converse County.

The upper Muddy r e s e r v o i r s p a n s an

a r e a of 4,838 a c r e s and averages 6 f e e t i n t h i c k n e s s .

Average p o r o s i t y

and p e r m e a b i l i t y w i t h i n t h e r e s e r v o i r a r e s i m i l a r t o t h o s e of t h e e q u i v a l e n t r e s e r v o i r of Block "A."

The primary producing mechanism

of t h e upper Muddy i s s o l u t i o n gas d r i v e . The i n i t i a l y e a r of t h e Block "B" Upper Muddy Unit w a t e r f l o o d p r o j e c t was 1961.

Four w e l l s were converted t o i n j e c t o r s t h a t y e a r .

Since t h e n , 3 1 i n j e c t i o n w e l l s have been added t o t h e p r o j e c t .

Twenty-

seven w e l l s a r e equipped a s d u a l i n j e c t i o n w e l l s , and 17 of t h e d u a l i n j e c t o r s were a c t i v e a s of December, 1979.

Over t h e l i f e of t h e

p r o j e c t , i n j e c t i o n p r e s s u r e s have ranged from a r e p o r t e d "vacuum" t o Current O i l and Gas Commission

a maximum p r e s s u r e of 3,700 p s i .

9 s t a t i s t i c s i n d i c a t e t h a t 64,338,960 b a r r e l s (2.7022 x 10 g a l l o n s ) of produced Madison Limestone and Tensleep Sandstone water have been i n j e c t e d s i n c e t h e p r o j e c t began. Block "B"

Lower Muddy Unit

The Lower Muddy Unit of t h e "B"

Block i s i n t h e s o u t h - c e n t r a l p a r t

of South Glenrock F i e l d a d j a c e n t t o M and K O i l o p e r a t i o n ' s lower Muddy p r o j e c t i n Block "C"

t o t h e west.

The Block "B"

lower Muddy r e s e r v o i r

i n c l u d e s 1,129 a c r e s w i t h an average pay t h i c k n e s s of 17 f e e t .

The

average p o r o s i t y and p e r m e a b i l i t y of t h e r e s e r v o i r a r e 14 p e r c e n t and 82 m i l l i d a r c i e s , r e s p e c t i v e l y .

The primary r e s e r v o i r producing

mechanism i s s o l u t i o n g a s d r i v e . Waterflooding of t h e lower Muddy r e s e r v o i r began i n 1963, using a l i n e d r i v e type i n j e c t i o n p a t t e r n . i n t h e w a t e r f l o o d s i n c e 1963. a s of December, 1979.

Twenty-nine w e l l s have been involved

T h i r t e e n of t h e w e l l s remained a c t i v e

Eight of t h e a c t i v e w e l l s and 8 of t h e s h u t - i n

w e l l s a r e equipped f o r d u a l tubing and annulus i n j e c t i o n .

Between

9 1963 and t h e end of 1979, 26,804,160 b a r r e l s (1.1258 x 10 g a l l o n s ) of produced Madison Limestone and Tensleep Sandstone water were i n j e c t e d i n t o t h e Lower Muddy Sandstone of Block '%I1.

Block "B" Dakota Unit The Dakota r e s e r v o i r of Block "B"

encompasses 4,249 a c r e s w i t h

an average pay zone t h i c k n e s s of 27 f e e t .

The primary r e s e r v o i r

producing mechanisms were s o l u t i o n gas d r i v e and p a r t i a l water d r i v e . Average p o r o s i t y and p e r m e a b i l i t y of t h e Dakota "B" r e s e r v o i r a r e 14 p e r c e n t and 75 m i l l i d a r c i e s , r e s p e c t i v e l y . A l i n e d r i v e p a t t e r n water i n j e c t i o n p r o j e c t was s t a r t e d by C o n t i n e n t a l O i l Company i n September, 1961.

By 1971, 36 i n j e c t i o n

w e l l s were involved i n t h e Dakota "B" w a t e r f l o o d . the wells a r e dual injectors. s h u t - i n by t h e end of 1979.

Twenty-eight of

Ten of t h e s e d u a l i n j e c t o r s had been A s of December, 1979, 123,321,688 b a r r e l s

9 (5.1795 x 10 g a l l o n s ) of produced Madison Limestone and Tensleep Sandstone water had been i n j e c t e d i n t o t h e Dakota r e s e r v o i r .

Injection

p r e s s u r e s ranged t o a maximum of 3,040 p s i .

Block "C" Lower Muddy Unit The u n i t p a r t i c i p a t i n g a r e a of t h e lower Muddy Unit of Block "C" i s 4,736 a c r e s .

The lower Muddy r e s e r v o i r covers 2,253 a c r e s i n t h e

southwest p a r t of South Glenrock F i e l d and l i e s a d j a c e n t t o t h e lower Muddy "B"

p r o j e c t operated by C o n t i n e n t a l O i l Company.

Average

t h i c k n e s s of t h e pay zone i s 12 f e e t , p o r o s i t y averages 14 p e r c e n t and p e r m e a b i l i t y averages 82 m i l l i d a r c i e s .

S o l u t i o n gas d r i v e i s t h e

primary producing mechanism of t h e r e s e r v o i r .

I n June, 1961, a water i n j e c t i o n p r o j e c t began w i t h t h r e e w e l l s i n a l i n e drive pattern.

By 1969, t h e p r o j e c t had been expanded t o

29 w e l l s and by 1974, a l l of t h e w e l l s had been shut-in.

A cumulative

8 t o t a l of 16,226,190 b a r r e l s (6.815 x 10 g a l l o n s ) of Madison Limestone water h a s been i n j e c t e d i n t o t h e r e s e r v o i r .

Average i n j e c t i o n well-

head p r e s s u r e s ranged from a minimum of 125 p s i t o a maximum of 2,800 psi.

Casing Record:

I n j e c t i o n Well #49, T33N-R76W-33 dcb, South Glenrock F i e l d , Block "C" Lower Muddy U n i t , T o t a l Depth = 6133 f e e t . Casing S i z e 9-5/8"

Wt.

(#/ft) 32

Amount 241'

Golden P r a i r i e F i e l d (1,891,522 b b l s o i l , 15,134 MCF gas; 1937-79) E a s t 5-2 Unit Golden P r a i r i e F i e l d i s l o c a t e d i n t h e c e n t r a l Denver Basin i n Township 16 North, Range 6 1 West, Laramie County.

O i l was discovered

a t Golden P r a i r i e i n 1937, and water i n j e c t i o n s t a r t e d i n 1969. The E a s t 5-2 sand i s a member of t h e Muddy Sandstone which occurs a t a depth of about 7,650 f e e t i n t h e Golden P r a i r i e a r e a .

Injection

of f r e s h shallow sand water and produced Muddy w a t e r amounted t o 1,905,305 7 b a r r e l s (8.0023 x 1 0 g a l l o n s ) between 1969 and December, 1979.

Only

two w e l l s have been u t i l i z e d f o r t h e i n j e c t i o n p r o j e c t and b o t h a r e a c t i v e according t o O i l and Gas Commission s t a t i s t i c s . w e l l p r e s s u r e s have ranged from 200 t o 2,400 p s i .

Average i n j e c t i o n

Casing Record:

I n j e c t i o n Well #5, T16N-R61W-22 bdb, Golden P r a i r i e F i e l d , East 5-2 U n i t , T o t a l Depth = 7798 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

8-5 / 8"

24

12-1/4"

350 '

350 sacks

4-1/2"

11.6,10.5

7-7/8"

7850'

200 sacks

Grass Creek F i e l d (159,521,582 b b l s o i l , 6,004,635 MCF gas; 1914-79) Grass Creek F i e l d i s l o c a t e d on t h e southwest r i m of t h e Bighorn Basin.

O i l was f i r s t discovered i n June, 1914, w i t h t h e completion of

a w e l l i n t h e F r o n t i e r Formation.

One year l a t e r o i l was found i n t h e

Muddy Sandstone. S t r u c t u r a l l y , Grass Creek i s a l a r g e , crescent-shaped,

double

plunging, northwest-southeast t r e n d i n g , asymmetrical a n t i c l i n e which forms a topographic b a s i n eroded i n t h e s o f t Cody Shale, w i t h a g e n t l e d i p of 10 t o 15O northeastward i n t o t h e Bighorn Basin. southwest f l a n k of t h e s t r u c t u r e d i p s 35 t o 40'

The s t e e p

i n t o a major t h r u s t

f a u l t w i t h about 2,000 f e e t of displacement and is on t h e convex o r mountainward s i d e of t h e s t r u c t u r e .

Along t h e northwest s i d e of t h e

s t r u c t u r e t h e r e i s a northeast trending, sharp, s y n c l i n a l f o l d t h a t s e p a r a t e s Grass Creek a n t i c l i n e from L i t t l e Grass Creek dome.

The

b a s i n i s completely surrounded by a r i m of ridge-forming Mesaverde Formation except a t 4 s p o t s where i t i s c u t by stream e r o s i o n .

Phosphoria-Tensleep Unit The Phosphoria-Tensleep Unit of Grass Creek F i e l d encompasses an a r e a of 3,016 a c r e s i n Township 46 North, Ranges 98 and 99 West, Hot Springs County.

The p a r t i c i p a t i n g a r e a i s under f e d e r a l , s t a t e , and

p r i v a t e ownership and i s operated by Marathon O i l Company.

The

r e s e r v o i r c o n s i s t s of permeable zones i n t h e Phosphoria Formation and Tensleep Sandstone.

Black o i l was discovered i n both f o r m a t i o n s i n

1922. The Permian age Phosphoria Formation ( o f t e n c a l l e d Embar i n o i l f i e l d s ) i s composed of dolomite, limestone and s h a l e w i t h a g r o s s t h i c k It i s d i v i d e d i n t o two d i s t i n c t p o r o s i t y zones:

n e s s of up t o 240 f e e t .

t h e upper, which h a s a g r o s s t h i c k n e s s of about 60 f e e t ; and t h e middle, w i t h a g r o s s t h i c k n e s s of about 45 f e e t .

Only t h e d o l o m i t i c p o r t i o n of

t h e s e zones i s of r e s e r v o i r q u a l i t y and t h e p o r o s i t y i s predominantly intercrystalline.

The upper and lower zones have t h i c k n e s s e s of 22 and

14 f e e t , r e s p e c t i v e l y .

Average p o r o s i t y i s 18.5 p e r c e n t and average

p e r m e a b i l i t y i s 20.4 m i l l i d a r c i e s . The Tensleep Sandstone i s a Pennsylvanian sandstone of moderate t o poor s o r t i n g , subangular rounding and v e r y f i n e a g r o s s t h i c k n e s s of 250 f e e t .

t o f i n e grain s i z e with

The r e s e r v o i r h a s 6 s i g n i f i c a n t p o r o s i t y

zones which a r e s e p a r a t e d by t i g h t dolomite and sandstone over l a r g e p o r t i o n s of t h e r e s e r v o i r .

I n d i v i d u a l Tensleep pay zones have average

p o r o s i t i e s and p e r m e a b i l i t i e s which range from 10.6 t o 15.6 p e r c e n t and 15 t o 152 m i l l i d a r c i e s , r e s p e c t i v e l y . The r e s e r v o i r energy f o r b o t h t h e Phosphoria and t h e Tensleep i s provided, p r i m a r i l y , by a p a r t i a l water d r i v e .

Water i n j e c t i o n began

i n 1975, w i t h d u a l i n j e c t i o n i n t o b o t h r e s e r v o i r s .

The i n j e c t i o n w e l l s

were arranged i n a n i n v e r t e d 7-spot c o n f i g u r a t i o n around t h e producing wells.

Water i s s u p p l i e d by producing Grass Creek w e l l s and by

f r e s h water supply w e l l s i n shallow sands and t h e Madison Limestone. By January, 1979, t h e i n j e c t i o n f i e l d had expanded t o 35 w e l l s , 17 of which a r e d u a l i n j e c t o r s .

Twenty-three w e l l s were a c t i v e a t t h a t time

and cumulative i n j e c t i o n through a l l w e l l s t o t a l e d 56,648,710 b a r r e l s 9 (2.3792 x 10 g a l l o n s ) of w a t e r .

Casing d a t a were u n a v a i l a b l e f o r

t h i s writing.

C u r t i s Unit The Upper J u r a s s i c C u r t i s Formation, p r i m a r i l y a fine-grained r e d sandstone, was discovered t o be o i l productive i n t h e Grass Creek F i e l d a r e a i n 1952.

The ensuing development r e s u l t e d i n 1 6 1 producing w e l l s

i n t h e C u r t i s sand.

The C u r t i s Unit p a r t i c i p a t i n g a r e a i n c l u d e s 7,377

a c r e s of f e d e r a l , s t a t e , and p r i v a t e land.

The underlying r e s e r v o i r

i n c l u d e s 5,800 a c r e s and has an average pay zone t h i c k n e s s of approximately 20 f e e t . A p i l o t water i n j e c t i o n p r o j e c t s t a r t e d i n 1959, w i t h t h e purpose of supplementing t h e d e p l e t e d r e s e r v o i r p r e s s u r e through t h e c r e a t i o n of an a r t i f i c i a l edgewater encroachment.

One y e a r l a t e r t h e p r o j e c t

was expanded t o a f u l l s c a l e l i n e d r i v e p a t t e r n waterflood.

According

t o t h e most r e c e n t O i l and Gas Commission f i l e s on t h e C u r t i s Unit, 9 (January, 1979), 149,772,217 b a r r e l s (6.2903 x 10 g a l l o n s ) of Mesaverde Formation, Madison Limestone, and Bighorn Dolomite water have been i n j e c t e d through 74 w e l l s , 39 of which were a c t i v e i n j e c t o r s .

Casing

d a t a were u n a v a i l a b l e f o r t h i s w r i t i n g .

Pre-Tensleep Unit The Pre-Tensleep Unit i n c l u d e s 715 a c r e s of f e d e r a l , s t a t e , and f e e land i n Township 46 North, Range 98 West, Hot Springs County.

The

u n i t was formed t o e f f i c i e n t l y o p e r a t e production from, and i n j e c t i o n i n t o , theDarwin and Madison r e s e r v o i r s .

The Darwin r e s e r v o i r covers

about 460 a c r e s and has an average pay t h i c k n e s s of 19 f e e t ,

The

underlying Madison Limestone is approximately 550 f e e t t h i c k and i s composed p r i m a r i l y of dolomite w i t h numerous zones of e x c e l l e n t p o r o s i t y . Water i n j e c t i o n began i n June, 1966, i n t h e n o r t h e a s t p a r t of t h e Darwin r e s e r v o i r .

Seven w e l l s , two of which w e r e s t i l l a c t i v e a s of

January, 1979, had i n j e c t e d a cumulative volume of 3,473,681 b a r r e l s 8 (1,4589 x 10 g a l l o n s ) of Madison Limestone and Bighorn Dolomite water between 1966 and 1979.

The average i n j e c t i o n p r e s s u r e during t h a t

period was 550 p s i . F r o n t i e r Unit The F r o n t i e r Formation was t h e f i r s t formation t o produce o i l a t Grass Creek F i e l d .

The i n i t i a l w e l l was completed i n 1914 and by 1918,

421 w e l l s had been d r i l l e d i n 9 d i f f e r e n t sand zones w i t h i n t h e Frontier.

The F r o n t i e r Unit covers 2,490 a c r e s of f e d e r a l , s t a t e , and

p r i v a t e land.

The r e s e r v o i r i n c l u d e s 1,660 a c r e s and has an average

pay zone t h i c k n e s s of 55 f e e t . A water i n j e c t i o n p i l o t p r o j e c t s t a r t e d i n 1960 i n t h e t h i r d and f i f t h F r o n t i e r sands, using water produced from Embar (Phosphoria) Formation and Tensleep Sandstone w e l l s .

Because t h e produced water was

corroding p i p e s , water from t h e Mesaverde Formation, Madison Limestone, and Bighorn Dolomite was s u b s t i t u t e d when t h e p r o j e c t was expanded t o a f u l l s c a l e p e r i p h e r a l waterflood.

Sixty-nine w e l l s , 9 of them d u a l

i n j e c t o r s , have been u t i l i z e d i n t h e p r o j e c t .

A s of January, 1977,

39 w e l l s were s t i l l a c t i v e and a cumulative volume of 86,592,914 b a r r e l s 9 (3.6369 x 10 g a l l o n s ) of water had been i n j e c t e d during t h e course of the project.

I n j e c t i o n p r e s s u r e s have averaged between 400 and 565 p s i

a t t h e wellheads.

Among t h e F r o n t i e r zones c u r r e n t l y (January, 1979)

r e c e i v i n g i n j e c t e d water a r e t h e "B"

F r o n t i e r , t h e "C"

F r o n t i e r and t h e

second, t h i r d , f o u r t h , and f i f t h F r o n t i e r sands.

Green River Bend F i e l d (9,015,674 b b l s o i l , 135,550,630 MCF gas; 1958-79) Almy Birch Creek Unit Since t h e i n j e c t i o n p r o j e c t s a t t h e Birch Creek Sand Unit and t h e Almy T-5 Sand Unit have been shut-in s i n c e 1970, I have combined them i n t o one unit--the

Almy Birch Creek--to

b r i e f l y d e s c r i b e t h e i r water

injection history. Green River Bend F i e l d i s l o c a t e d i n Townships 26 and 27 Horth, Ranges 112 and 113 West, i n Lincoln and S u b l e t t e c o u n t i e s . spans 15,025 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land.

The f i e l d

Two water

i n j e c t i o n p r o j e c t s were a c t i v e i n Green River Bend u n t i l 1970, when both were d i s c o n t i n u e d . The T-5 Sand U n i t , operated by Belco Petroleum Corporation, began i n j e c t i n g water i n t o t h e Almy T-5 sand i n September, 1964.

The Almy

r e s e r v o i r covers 270 a c r e s and has an average pay zone t h i c k n e s s of approximately 23 f e e t .

Water i n j e c t i o n w e l l s were p e r f o r a t e d a t t h e

oil-water and o i l - g a s c o n t a c t s .

I n j e c t i o n a t t h e o i l - g a s c o n t a c t was

done t o prevent encroachment of o i l i n t o t h e "dry" gas cap.

Water f o r

t h e i n j e c t i o n p r o j e c t was obtained from t h e upper sands of t h e Almy member of t h e Wasatch Formation. I n 1967, water i n j e c t i o n began a t t h e Birch Creek Sand U n i t , which covers 185 a c r e s of s t a t e and f e d e r a l land. November, 1970.

I n j e c t i o n was h a l t e d i n

Cumulative i n j e c t i o n f o r b o t h u n i t s , t h r o u g h 1970, was 2,236,859 b a r r e l s (93,948,078 g a l l o n s ) of f r e s h and produced water from t h e Almy sand. I n j e c t i o n W e l l /IT-9, T27N-R113W-36 c c a , Green R i v e r Bend F i e l d , Almy B i r c h Creek U n i t , T o t a l Depth = 2630 f e e t .

Casing Record:

Casing S i z e

Wt.

Hole S i z e

(#/ft)

11"

8-5 18"

24

5-112"

14,15.5

7-7 /8"

Cement

Purpose

149 '

60 s a c k s

Surface

2557 '

150 s a c k s

Amount

Injection

G r e y b u l l F i e l d (989,012 b b l s o i l ; 1907-79) Peay U n i t The Peay U n i t of G r e y b u l l F i e l d i s l o c a t e d i n S e c t i o n s 8 and 17 of Township 52 North, Range 93 West, Big Horn County, . O i l was d i s c o v e r e d i n t h e G r e y b u l l sand i n 1907, and s u b s e q u e n t l y i n t h e Peay sand.

The

u n i t p a r t i c i p a t i n g area i n c l u d e s 81.5 a c r e s of p r i v a t e l a n d . Water i n j e c t i o n i n t o t h e s h a l l o w Peay r e s e r v o i r (212-284 f e e t deep) was s t a r t e d i n 1967.

Seven w e l l s a t e a c t i v e l y i n j e c t i n g i n t o t h e Peay

a c c o r d i n g t o most r e c e n t ( J a n u a r y , 1979) i n j e c t i o n r e p o r t s from Wilson O i l Corporation.

The c u m u l a t i v e volume i n j e c t e d was r e p o r t e d a s

907,325 b a r r e l s (38,107,650 g a l l o n s ) of produced Peay w a t e r . Both i n j e c t i o n w e l l s of t h e C a r l s o n U n i t of G r e y b u l l F i e l d have been s h u t - i n and i n j e c t i o n d a t a were u n a v a i l a b l e f o r t h i s w r i t i n g . Casing Record:

I n j e c t i o n Well #3, T52N-R93W-17 cdd, G r e y b u l l F i e l d , Peay U n i t , T o t a l Depth = 375 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

Purpose

13-3/8"

40

27'

Conductor

9-518

24

99'

Surface

Casing Record:

Casing S i z e

I n j e c t i o n W e l l #1P, T52N-R93W-17 cdc, G r e y b u l l F i e l d , C a r l s o n U n i t , T o t a l Depth = 1287 f e e t . Wt.

8-518" 2-7 18"

(#If t )

Hole S i z e

24

8-5/8"

6.5

7-718"

Depth S e t 30 ' 1287 ' (tubing)

Purpose

Cement

-

Surf a c e Injection

50 s a c k s

G r i e v e F i e l d (29,614,836 b b l s o i l , 61,014,939 MCF g a s ; 1954-79) Muddy U n i t The Muddy U n i t of G r i e v e F i e l d i s l o c a t e d i n Township 32 North, Range 85 West, Natrona County.

U n t i l 1974, i n j e c t i o n o p e r a t i o n s of t h e

Muddy U n i t i n c l u d e d w a t e r i n j e c t i o n , g a s i n j e c t i o n , and s a l t w a t e r d i s p o s a l , a l l i n t o t h e Muddy Sandstone.

No i n j e c t i o n r e p o r t s have been

f i l e d by t h e o p e r a t o r , F o r e s t O i l C o r p o r a t i o n , s i n c e 1974.

At t h a t t i m e ,

31,078,856 m i l l i o n c u b i c f e e t of d r y g a s had been i n j e c t e d a t a v e r a g e w e l l h e a d p r e s s u r e s r a n g i n g from 1 , 5 6 1 t o 1 , 8 5 0 p s i .

Between 1970 and

8 December, 1974, 2,669,065 b a r r e l s (1.121 x 1 0 g a l l o n s ) of produced s a l t w a t e r from t h e Muddy Sandstone were d i s p o s e d of i n t h e same

formation.

I n j e c t i o n p r e s s u r e s a t t h e d i s p o s a l w e l l h e a d , averaged over

6 month p e r i o d s , covered a r a n g e between 1 , 6 0 0 and 1,952 p s i . Guthery F i e l d (2,532,774 b b l s o i l , 318,343 MCF g a s ; 1963-79) Minnelusa U n i t O i l was d i s c o v e r e d i n t h e Minnelusa Formation a t Guthery F i e l d i n

October, 1963.

Three d i s t i n c t zones of p o r o s i t y have been r e c o g n i z e d

w i t h i n t h e upper Minnelusa and each one i s bounded by a n updip f a c i e s change o r t r u n c a t i o n by an Opeche S h a l e p a l e o c h a n n e l .

The Opeche

forms s t r a t i g r a p h i c t r a p s t o t h e n o r t h and east w h i l e t h e s o u t h and w e s t s i d e s of t h e r e s e r v o i r a r e bounded by a n o i l - w a t e r c o n t a c t .

The

average p o r o s i t y of t h e Minnelusa pay zone, a s determined by c o r r e l a t i o n of c o r e d a t a w i t h e l e c t r i c l o g a n a l y s e s , i s 18.9 p e r c e n t .

Permeability

ranges from 2 t o 935 m i l l i d a r c i e s and averages 184 m i l l i d a r c i e s .

The

primary r e s e r v o i r producing mechanism i s f l u i d expansion w i t h minor e f f e c t s from water d r i v e and g r a v i t y d r a i n a g e .

Maximum c l o s u r e of t h e

Minnelusa r e s e r v o i r above t h e i n t e r p r e t e d oil-water c o n t a c t i s approximately 115 f e e t . Water i n j e c t i o n a t Guthery F i e l d s t a r t e d i n 1968, and has t o t a l e d 8 3,864,802 b a r r e l s (1.623 x 10 g a l l o n s ) of Fox H i l l s Sandstone w a t e r , according t o i n j e c t i o n r e p o r t s from December, 1979. Half Moon F i e l d (4,073,598 b b l s o i l ; 1944-79) Morrison Unit The Morrison Unit of Half Moon F i e l d i s t h e s i t e of a two we s a l t water d i s p o s a l system t h a t began o p e r a t i n g i n 1971, and was shut-in during J u l y , 1979.

Both w e l l s a r e l o c a t e d i n S e c t i o n 23, Township 5 1

North, Range 102 West, Park County, and a r e p e r f o r a t e d i n t h e Ernbar Formation and Tensleep Sandstone a t depths of 3,357 and 3,380 f e e t . t h e w e l l s were s h u t - i n ,

When

t h e cumulative volume of b r i n e t h a t had been

8 i n j e c t e d through both w e l l s was 15,096,198 b a r r e l s (6.3404 x 10 g a l l o n s ) .

The maximum average i n j e c t i o n p r e s s u r e was 407 p s i . Casing Record:

S a l t Water Disposal Well 111, T51N-R102W-23 bca, Half Moon F i e l d , Morrison Unit.

Casing S i z e

Wt.

( m t )

Depth S e t

7"

23

3550'

7"

13

3652'

5" l i n e r

3536-3665'

Cement 350 s a c k s

22 sacks

Halverson Ranch F i e l d (12,621,988 b b l s o i l , 208,436 MCF gas; 1961-79) Minnelusa Unit Halverson Ranch F i e l d i s l o c a t e d on t h e e a s t f l a n k of t h e Powder River Basin approximately 14 m i l e s e a s t - s o u t h e a s t of G i l l e t t e . was discovered i n t h e Minnelusa Formation i n 1962. p a r t i c i p a t i n g a r e a i n c l u d e s 2,383 a c r e s . Minnelusa r e s e r v o i r i s 1,750 a c r e s . Minnelusa "A"

and "B"

Oil

The Minnelusa Unit

The a r e a l e x t e n t of t h e

The Permian sands of t h e upper

pay zones a r e c l e a n , v e r y f i n e - g r a i n e d , porous,

permeable sands w i t h o c c a s i o n a l s t r e a k s of t i g h t , a n h y d r i t i c dolomite. Average pay zone t h i c k n e s s , determined from s o n i c l o g a n a l y s i s i s 30 feet.

S t r a t i g r a p h i c hydrocarbon entrapment i s provided by t r u n c a t i o n

of t h e Minnelusa sand on t h e e a s t e r n updip edge and by t h e oil-water c o n t a c t downstructure t o t h e west. zone.

The "B"

sand i s t h e main producing

The p r i n c i p a l r e s e r v o i r producing mechanism i s s o l u t i o n gas

drive.

It h a s been concluded t h a t t h e r e s e r v o i r i s n o t being a f f e c t e d

by an a c t i v e water d r i v e s i n c e r e s e r v o i r p r e s s u r e i s d e c l i n i n g and no s i g n i f i c a n t encroachment of water has been d e t e c t e d .

Estimates of

f i e l d average p o r o s i t y and p e r m e a b i l i t y a r e 1 3 p e r c e n t and 56 m i l l i darcies, respectively. A l i n e d r i v e type waterflood system was s t a r t e d i n 1967.

The l i n e

d r i v e p a t t e r n was u t i l i z e d t o accommodate t h e elongated shape of t h e Halverson Ranch F i e l d , t h e producing w e l l development p a t t e r n , and t h e o r i e n t a t i o n of t h e Minnelusa sand s t r u c t u r e .

Between 1967 and December,

9 1979, 15 i n j e c t i o n w e l l s pumped 35,268,929 b a r r e l s (1.4813 x 10 g a l l o n s ) of f r e s h Fox H i l l s and produced Minnelusa Formation water i n t o the reservoir.

Eleven of t h e w e l l s were a c t i v e a t t h a t time, 3 had

been temporarily s h u t - i n and one w e l l was permanently abandoned.

Two

h o l e s were found i n t h e t u b i n g s t r i n g of i n j e c t i o n w e l l #13 i n 1976. The h o l e s were plugged immediately a f t e r t h e d i s c o v e r y was made w i t h no s i g n i f i c a n t consequences.

I n j e c t i o n Well # l 3 , T49N-R69W-17 cba, Halverson Ranch F i e l d , Minnelusa U n i t , T o t a l Depth = 8730 f e e t .

Casing Record: Casing S i z e

Wt.

10-3/4" 5-1/2"

(#/ft) 40.5

Hole S i z e 15"

15.5,17

3-7 /8"

Depth S e t 40 15.5,17

Purpose

Cement

Surf a c e

645 sacks

I n je c t i o n

500 sacks

Hamilton Dome F i e l d (201,492,981 b b l s o i l , 82,698 MCF gas; 1918-79) I n September, 1918, a producing o i l w e l l was completed i n t h e C u r t i s sand of t h e Chugwater Formation, marking t h e d i s c o v e r y of t h e Hamilton Dome F i e l d .

The f i e l d i s l o c a t e d i n Hot Springs County, about

20 m i l e s northwest of Thermopolis on a l o c a l c l o s u r e of t h e Thermopolis anticline. The a n t i c l i n e i s a r e g i o n a l , east-west t r e n d i n g f e a t u r e which extends some 30 m i l e s a c r o s s t h e southwest c o r n e r of t h e Bighorn Basin.

The s o u t h f l a n k of t h e s t r u c t u r e d i p s a s much a s 90'

into a

system of n e a r v e r t i c a l northwest-southeast t r e n d i n g t h r u s t f a u l t s w i t h up t o 4,500 f e e t of t o t a l displacement.

Total structural closure is

approximately 2,000 f e e t i n t o t h e s a d d l e i n t h e eastward plunge of the anticline.

A north-south t r e n d i n g t h r u s t f a u l t c u t s t h e w e s t

end of t h e a n t i c l i n e , s e p a r a t i n g t h e r e s e r v o i r between S e c t i o n s 10 and 15 i n Township 44 North, Range 98 West.

Phosphoria Unit The Phosphoria Unit of Hamilton Dome F i e l d i s l o c a t e d i n Township 44 North, Ranges 97 and 98 West, Hot Springs County.

O i l was discovered

i n t h e Phosphoria Formation i n 1919.

The Phosphoria i s composed of

d o l o m i t i c l i m e s t o n e and d o l o m i t e i n t e r b e d d e d w i t h s h a l e and a n h y d r i t e . Gross t h i c k n e s s of t h e Phosphoria v a r i e s from 160 t o 200 f e e t .

The

p r o d u c t i v e p a r t of t h e f o r m a t i o n i s found n e a r t h e t o p and c o n s i s t s of up t o 60 f e e t of i n t e r b e d d e d , m i c r o c r y s t a l l i n e , f o s s i l i f e r o u s l i m e s t o n e s and d o l o m i t e s .

The t h i c k n e s s of t h e pay zone r a n g e s from 4 t o

47 f e e t and a v e r a g e s 28 f e e t t h i c k .

P o r o s i t i e s and p e r m e a b i l i t i e s ,

w i t h i n t h e producing zone, a r e h i g h l y v a r i a b l e .

Among 16 producing

w e l l s i n t h e P h o s p h o r i a r e s e r v o i r which have c o r e d a t a c o n s i d e r e d r e p r e s e n t a t i v e of t h e r e s e r v o i r , p o r o s i t y r a n g e s from 5.9 p e r c e n t t o 3 5 . 1 p e r c e n t and a v e r a g e s 21.5 p e r c e n t .

A t t h e same w e l l s , c o r e

p e r m e a b i l i t y ( a i r p e r m e a b i l i t y ) r a n g e s from .90 t o 1,000 m i l l i d a r c i e s w i t h a n a v e r a g e of 85 m i l l i d a r c i e s .

However, w e l l p r o d u c t i v i t i e s

i n d i c a t e t h a t t h e e f f e c t i v e p e r m e a b i l i t y of t h e r e s e r v o i r , due presumably t o fracturing, is significantly higher.

The primary producing mechanism

i n t h e r e s e r v o i r is s o l u t i o n gas d r i v e , b u t a l i m i t e d water d r i v e appears t o have i n f l u e n c e d r e c o v e r y i n t h e v i c i n i t y of t h e west f a u l t and, t o a lesser d e g r e e , around t h e s t r u c t u r a l f l a n k s . The Phosphoria U n i t p a r t i c i p a t i n g a r e a i n v o l v e s 3,152 a c r e s of f e d e r a l land.

A l a r g e s c a l e w a t e r f l o o d of t h e Phosphoria s t a r t e d i n

1973, w i t h 27 w e l l s i n j e c t i n g .

One of t h e w e l l s i s a d u a l i n j e c t o r

completed i n t h e C u r t i s sand and t h e Phosphoria Formation. 1979, t h r e e of t h e w e l l s had been s h u t - i n .

By December,

Cumulative i n j e c t i o n t o t h a t

9 t i m e was 51,446,785 b a r r e l s (2.1608 x 10 g a l l o n s ) of produced w a t e r from t h e Tensleep Sandstone and Phosphoria Formation. p r e s s u r e s r a n g e t o a maximum of 1 , 2 0 0 p s i .

Injection

Casing Record:

I n j e c t i o n W e l l #106, T44N-R98W-24 adb, Hamilton Dome F i e l d , Phosphoria U n i t , T o t a l Depth = 2915 f e e t .

wt.

Casing S i z e

( w t )

Hole S i z e

Depth S e t

Cement

8-5/8"

32

12-1/4"

200'

120 s a c k s

5-1/2"

15.5

7-7/8"

2915 '

200 s a c k s

F e d e r a l Lease U n i t The F e d e r a l Lease U n i t of Hamilton Dome F i e l d i s l o c a t e d i n Township

44 North, Range 98 West, Hot S p r i n g s County.

Water i n j e c t i o n i n t o t h e

C u r t i s sand of t h e Chugwater Formation s t a r t e d i n 1970, and was d i s 8 c o n t i n u e d i n 1979, a f t e r 4,521,571 b a r r e l s (1.8991 x 10 g a l l o n s ) of produced T e n s l e e p Sandstone and Phosphoria Formation w a t e r had been injected.

Average i n j e c t i o n wellhead p r e s s u r e s d u r i n g t h e decade-long

p r o j e c t ranged from 1 0 t o 450 p s i . Casing Record:

I n j e c t i o n W e l l #13, T44N-R98W-11 b c c , Hamilton Dome F i e l d , F e d e r a l Lease U n i t , T o t a l Depth = 2714 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5/811

28

5-112"

15.5

Hole S i z e

Depth S e t 200 '

13" 7-7/8"

2800 '

Cement Solid t o surface 485 f t 3

Government 37697 U n i t The Government 37697 U n i t w a t e r i n j e c t i o n p r o j e c t was i n i t i a t e d i n 1970, w i t h i n j e c t i o n i n t o t h e f o u r t h C u r t i s sand.

The f o u r t h C u r t i s

r e s e r v o i r c o v e r s a b o u t 240 a c r e s w i t h a n e t pay zone t h i c k n e s s of 14 feet.

Water used f o r t h e i n j e c t i o n p r o j e c t i s s u p p l i e d by producing

w e l l s i n t h e C u r t i s sand and Tensleep Sandstone.

The'most r e c e n t i n j e c -

t i o n r e p o r t s on f i l e a t t h e O i l and Gas Commission ( J u n e , 1976) i n d i c a t e t h a t a l l f i v e i n j e c t i o n w e l l s have been s h u t - i n and t h a t 3,091,118 8 b a r r e l s (1.2983 x 1 0 g a l l o n s ) of produced water have been i n j e c t e d

s i n c e t h e s t a r t of t h e f l o o d .

Average i n j e c t i o n p r e s s u r e s have v a r i e d

between a minimum of 1 2 and a maximum of 1,200 p s i .

Reservoir responses

t o t h e w a t e r f l o o d have s u p p l i e d s t r o n g e v i d e n c e f o r h y d r a u l i c communic a t i o n between t h e f o u r t h C u r t i s s a n d , t h e Phosphoria Formation, and t h e Tensleep Sandstone.

Casing Record:

I n j e c t i o n W e l l #I-7, T44N-R97W-7 c c b , Hamilton Dome F i e l d , Government 37697 U n i t , T o t a l Depth = 2950 f e e t .

Casing S i z e

Wt.

(///ft)

8-5/8"

28

5-1/2It

15.5

Hole S i z e

Depth S e t

12-1/4"

209 '

7-7 /8"

2948'

Cement 150 f t 3 (regular) 110 f t 3 (pozmix)

Government 54257 U n i t The Government 54257 U n i t a l s o i n v o l v e s a w a t e r i n j e c t i o n p r o j e c t i n t h e f o u r t h C u r t i s sand i n t h e same a r e a a s t h e Government 37697 U n i t (T44N-R97 and 98W).

The p r o j e c t s t a r t e d i n 1966 and, as of J u n e , 1976,

8 4,233,736 b a r r e l s (1.7782 x 1 0 g a l l o n s ) of produced C u r t i s sand and Tensleep Sandstone w a t e r had been i n j e c t e d .

The s t a t u s of a l l f o u r of

t h e i n j e c t o r s i n J u n e , 1976, w a s t e m p o r a r i l y s h u t - i n .

Average i n j e c t i o n

p r e s s u r e s a t t h e w e l l h e a d ranged from 211 t o 1 , 3 6 5 p s i . On August 30, 1972, a l e a k was r e p o r t e d i n i n j e c t i o n w e l l //I-11 (TUN-R98W-11

cbc).

Water was b e i n g i n j e c t e d a t t h e r a t e of 692 b a r r e l s

p e r day a t a w e l l h e a d p r e s s u r e of 800 p s i .

O p e r a t o r s of t h e w e l l

measured l e a k a g e t o t h e s u r f a c e a t t h e r a t e of 321 b a r r e l s p e r day. The h o l e s were immediately plugged between 700 and 2,400 f e e t w i t h 900 s a c k s of cement.

Casing s c h e d u l e s f o r t h e i n j e c t i o n w e l l s were n o t

available f o r t h i s writing.

Hamm F i e l d (5,406,007 b b l s o i l , 91,979 MCF gas; 1967-79) Minnelusa Unit Hamm F i e l d i s l o c a t e d i n S e c t i o n s 20 and 29, Township 5 1 North, O i l was discovered i n t h e "B"

Range 69 West, Campbell County. of t h e Minnelusa Unit i n 1966.

The "B"

sand

sand i s t h e only o i l producing

reservoir i n the field. The Minnelusa "B"

sand r e s e r v o i r i s composed of c l e a r , f i n e - g r a i n e d ,

w e l l t o moderately cemented sandstone and h a s an average t h i c k n e s s of approximately 35 f e e t .

The depth t o t h e top of t h e Minnelusa Formation

ranges from 7,900 t o 7,950 f e e t i n t h e Ham F i e l d a r e a .

The r e s e r v o i r

covers 391 a c r e s w i t h production l i m i t e d by t r u n c a t i o n of beds t o t h e e a s t , n o r t h , and south and by an oil-water c o n t a c t downdip t o t h e west. P o r o s i t y of t h e r e s e r v o i r , 19.7 p e r c e n t , was given a s a weighted average from c o r e r e l a t e d l o g a n a l y s e s .

Core a n a l y s e s of 212 samples

were used t o determine t h e average p e r m e a b i l i t y of 239 m i l l i d a r c i e s . The o r i g i n a l recovery mechanism was f l u i d and rock expansion of t h e r e s e r v o i r and contiguous a q u i f e r .

Expansion of t h e a q u i f e r and with-

drawal of f l u i d s from t h e r e s e r v o i r have r e s u l t e d i n water encroachment and have provided a d d i t i o n a l r e s e r v o i r energy. 8 Between 1972 and June, 1979, 5,155,713 b a r r e l s (2.1654 x 10

g a l l o n s ) of water from t h e Fox H i l l s Sandstone were i n j e c t e d i n t o t h e I1

B 11 r e s e r v o i r of t h e Minnelusa Formation.

The average i n j e c t i o n p r e s s u r e s

during t h e p r o j e c t have ranged from 1,175 t o 2,637 p s i . w e l l s were temporarily shut-in a s of June, 1979.

Both i n j e c t i o n

Casing Record:

Casing S i z e

I n j e c t i o n Well #7, T51N-R69W-29 b a , Hamm F i e l d , Minnelusa U n i t , T o t a l Depths = 8094 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-5 /8"

24

12-1/4"

366'

300 s a c k s

Surface

5-1/2"

17,20

7-7/8"

8094'

300 s a c k s

Injection

Happy S p r i n g s F i e l d (8,073,713 b b l s o i l , 4,572,780 MCF g a s ; 1950-79) Dakota U n i t Happy S p r i n g s o i l f i e l d i s l o c a t e d a l o n g t h e s o u t h e r n margin of t h e Sweetwater u p l i f t i n Township 28 North, Range 93 West, Fremant County.

Between 1950 and 1953, o i l was d i s c o v e r e d i n t h e T e n s l e e p ,

Nugget, Muddy, and Lakota s a n d s t o n e s , t h e Phosphoria and F r o n t i e r f o r m a t i o n s and t h e Dakota sand. Water i n j e c t i o n i n t o t h e Dakota r e s e r v o i r s t a r t e d i n 1973, through one w e l l .

Produced w a t e r from F r o n t i e r and Dakota w e l l s h a s been t h e

s o u r c e of i n j e c t e d w a t e r .

Through December, 1979, 9,449,261 b a r r e l s

8 (3.9687 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d .

The Dakota U n i t

p a r t i c i p a t i n g a r e a c o v e r s 180 a c r e s of f e d e r a l l y owned l a n d .

The

c u r r e n t s t a t u s of t h e Dakota U n i t w a t e r f l o o d i s t e m p o r a r i l y s h u t - i n . F r o n t i e r Unit The Happy S p r i n g s F i e l d F r o n t i e r U n i t i n c l a d e s 320 a c r e s of f e d e r a l l a n d o p e r a t e d by Amoco P r o d u c t i o n Company. i n t o "A,"

"B,"

and "C"

The u n i t was d i v i d e d

a r e a s p r i o r t o t h e b e g i n n i n g of t h e "A"

a r e a w a t e r i n j e c t i o n p r o j e c t s i n 1958.

and "C"

Water i n j e c t e d i n t o t h e "C"

area a t t h e n o r t h end of t h e f i e l d from August, 1959 t o August, 1964, caused no r e s p o n s e i n t h e r e s e r v o i r .

The 236 a c r e s of p r o d u c t i v e r e s e r v o i r u n d e r l y i n g t h e "A" have an a v e r a g e pay zone t h i c k n e s s of 1 4 f e e t . p r o j e c t began i n 1958, and i s c u r r e n t l y s h u t - i n .

The "A"

area

area injection

The system was n o t

w i n t e r i z e d a t t h e o u t s e t , r e s u l t i n g i n a p r o j e c t shutdown between September, 1958, and October, 1960.

A s of June, 1979, 962,559 b a r r e l s

(40,427,478 g a l l o n s ) of s u r f a c e w a t e r had been i n j e c t e d through one well. Lakota U n i t The Lakota U n i t of Happy S p r i n g s F i e l d c o n s i s t s of two a c t i v e

s a l t water d i s p o s a l w e l l s .

The d i s p o s a l system was s t a r t e d i n 1977,

i n j e c t i n g b r i n e s from producing w e l l s i n t o t h e Lakota Sandstone. D e t a i l e d i n j e c t i o n d a t a were u n a v a i l a b l e .

Hidden Dome F i e l d (4,928,829 b b l s o i l , 22,295,371 MCF g a s ; 1918-79) Tensleep U n i t Hidden Dome F i e l d i s l o c a t e d i n t h e southwest c o r n e r of Township 48 North, Range 90 West, t h e s o u t h e a s t c o r n e r of Township 48 North, Range 9 1 West, and t h e n o r t h w e s t c o r n e r of Township 47 North, Range 90 West, Washakie County.

Waterflooding of t h e F r o n t i e r s t a r t e d i n 1960,

b u t was s h u t - i n by 1978. Another w a t e r f l o o d p r o j e c t began i n 1976, when t h e Tensleep Sandstone was flooded w i t h produced Tensleep w a t e r . have been involved i n t h e p r o j e c t .

Two i n j e c t i o n w e l l s

Cumulative i n j e c t i o n t o t a l s were

n o t a v a i l a b l e from O i l and Gas Commission f i l e s a t t h e t i m e of t h i s writing.

H i l i g h t F i e l d (66,475,815 b b l s o i l , 206,549,589 MCF g a s ; 1969-79) H i l i g h t F i e l d i s s i t u a t e d on t h e e a s t f l a n k of t h e Powder R i v e r Basin of northeastWyoming,approximately 30 m i l e s s o u t h of G i l l e t t e . The f i e l d was d i s c o v e r e d i n 1969, when a p r o d u c t i v e o i l w e l l was completed i n t h e Muddy Sandstone.

The s t r u c t u r e a s s o c i a t e d w i t h t h e

Muddy t r a p i s , e s s e n t i a l l y , a monocline w i t h l o c a l , s u b t l e n o s i n g .

No

s t r u c t u r a l c l o s u r e i s i n d i c a t e d by p r e s e n t s u b s u r f a c e c o n t r o l . R e g i o n a l l y , t h e n o r t h e a s t f l a n k of t h e Powder R i v e r Basin l i e s i n a n a r e a of m a r g i n a l m a r i n e Muddy sand development.

In Hilight Field

p r o p e r , u n i f o r m i t y of t h e Muddy s t r a t i g r a p h y and r e l a t i v e l y low w e l l density a t the present t i m e precludes r e l i a b l e geologic i n t e r p r e t a t i o n of t h e Muddy d e p o s i t i o n a l environment.

Current d a t a suggest a near-

s h o r e b a r o r p o s s i b l y a d e l t a i c t y p e sand d e p o s i t i o n .

The b a s i c t r a p

mechanism i s s t r a t i g r a p h i c a l l y c o n t r o l l e d and t h e r a n g e i n w e l l product i v i t y r e s u l t s p r i m a r i l y from v a r i a b l e s h a l i n e s s , i n t e r g r a n u l a r p o r o s i t y - p e r m e a b i l i t y and f r a c t u r e s , r a t h e r t h a n any s i g n i f i c a n t change i n sand t h i c k n e s s .

H i l i g h t F i e l d was d i v i d e d i n t o 3 u n i t s t o i n c r e a s e

t h e e f f i c i e n c y of p r o d u c t i o n from t h e Muddy r e s e r v o i r .

Average p o r o s i t y

and p e r m e a b i l i t y of t h e r e s e r v o i r a r e 20.3 p e r c e n t and 104 m i l l i darcies, respectively.

Grady U n i t The Grady U n i t of H i l i g h t F i e l d was e s t a b l i s h e d i n 1971, and c o v e r s 9,439 a c r e s i n Townships 45 and 46 North, Range 7 1 West, Campbell County.

Nine w e l l s have been i n v o l v e d i n t h e Grady U n i t w a t e r f l o o d .

8 C u r r e n t l y (December, 1 9 7 9 ) , 10,653,728 b a r r e l s (4.4746 x 1 0 g a l l o n s ) of f r e s h and produced Muddy Sandstone w a t e r have been i n j e c t e d i n t o

t h e Muddy r e s e r v o i r .

Only f o u r of t h e i n j e c t i o n w e l l s remain a c t i v e .

The rest have been temporarily shut-in.

Casing Record:

I n j e c t i o n Well #52, T45N-R71W-2 bd, H i l i g h t F i e l d , Grady U n i t , T o t a l Depth = 9365 f e e t .

Casing S i z e

Wt.

8-5/8"

(#/ft) 24

5-1/2"

various

Hole S i z e

Depth S e t

Cement

13-3/4"

727'

600 sacks

7-7/8"

9365'

300 s a c k s

Jayson Unit The Jayson Unit of H i l i g h t F i e l d covers most of Township 46 North, Range 70 West, Campbell County.

I n 1972, i n j e c t i o n i n t o t h e Muddy

r e s e r v o i r began i n t h e Jayson Unit. f r e s h and produced Muddy water.

By 1974, 15 w e l l s were i n j e c t i n g

Ten w e l l s were a c t i v e a s of December,

1979; however, cumulative i n j e c t i o n d a t a were n o t a v a i l a b l e from t h e f i l e s of t h e O i l and Gas Commission.

Casing Record:

I n j e c t i o n Well #w-0154562 2-3, T46N-R70W-31 a c c , H i l i g h t F i e l d , Jayson U n i t , T o t a l Depth = 9059 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

9-5/8"

36

13-1/2"

895 '

650 sacks

5-1/2"

17

7-718"

9059 '

350 sacks

C e n t r a l Unit The C e n t r a l Unit of H i l i g h t F i e l d i s by f a r t h e l a r g e s t of t h e t h r e e H i l i g h t u n i t s , covering an a r e a of 25,683 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land.

Water i n j e c t i o n s t a r t e d a t t h e C e n t r a l Unit i n 1972

and i n December, 1979, 32 of 48 e x i s t i n g i n j e c t o r s remained a c t i v e . Cumulative i n j e c t i o n a t t h a t p o i n t t o t a l e d 204,183,889 b a r r e l s (8.5757 9 x 10 g a l l o n s ) of f r e s h and produced Muddy Sandstone water.

Average

i n j e c t i o n p r e s s u r e s a t t h e wellhead ranged from 875 t o 2,348 p s i .

Casing Record:

I n j e c t i o n W e l l #132-1, T45N-R70W-9 cd, H i l i g h t F i e l d , C e n t r a l U n i t , T o t a l Depth = 9060 f e e t .

Casing S i z e

wt.

9-518"

( m t ) 36

5-112"

various

Hole S i z e

Depth S e t

Cement

13-314"

716 '

400 s a c k s

7-718"

9059 '

300 s a c k s

Horse Creek F i e l d (6,892,646 b b l s o i l , 216,947 MCF g a s ; 1942-79) Horse Creek U n i t The Horse Creek F i e l d d i s c o v e r y w e l l was completed i n t h e Lakota Sandstone i n 1942.

The f i e l d c o v e r s 2,342 a c r e s of f e d e r a l and p r i v a t e

l a n d i n Townships 16 and 17 North, Range 68 West, Laramie County.

Horse

Creek F i e l d was u n i t i z e d i n 1943, w i t h Mobil O i l C o r p o r a t i o n as u n i t operator.

Water i n j e c t i o n began i n 1960, t o supplement t h e e x i s t i n g

n a t u r a l w a t e r d r i v e of t h e Muddy r e s e r v o i r , which was d i s c o v e r e d p r o d u c t i v e i n t h e Horse Creek a r e a i n 1943. The w a t e r f l o o d w e l l c o n f i g u r a t i o n i s s e m i - p e r i p h e r a l a l o n g t h e d o w n s t r u c t u r e , east s i d e of t h e f i e l d .

Performance of t h e r e s e r v o i r

r e s u l t i n g from w a t e r i n j e c t i o n h a s been s a t i s f a c t o r y , though h i n d e r e d t o some d e g r e e by a known r e s e r v o i r f r a c t u r e system.

During t h e e a r l y

s t a g e s of t h e p r o j e c t , i n j e c t e d water moved i n t o f r a c t u r e s a l o n g t h e s o u t h e a s t edge of t h e f i e l d and watered o u t s e v e r a l of t h e s t r u c t u r a l l y lower w e l l s on t h e southwest edge of t h e a n t i c l i n e .

Waterflood r e s p o n s e

i n t h e n o r t h - c e n t r a l p a r t of t h e r e s e r v o i r h a s been b e t t e r a s a probable r e s u l t of more competent r e s e r v o i r rock. The Muddy r e s e r v o i r i n c l u d e s 2,340 a c r e s w i t h an a v e r a g e pay zone t h i c k n e s s of 23 f e e t .

Cumulative w a t e r i n j e c t i o n volumes between 1960

8 and December, 1979, were 20,122,940 b a r r e l s (8.4516 x 1 0 g a l l o n s ) .

Average i n j e c t i o n p r e s s u r e s f o r t h e same period ranged from vacuum t o 2,010 p s i .

Nine w e l l s a r e a c t i v e l y i n j e c t i n g .

Hunter Ranch F i e l d (810,778 b b l s o i l , 670,638 MCF gas; 1968-79) Muddy Unit Hunter Ranch F i e l d i s s i t u a t e d on a monoclinal s t r u c t u r e i n t h e n o r t h e r n Powder River Basin, one m i l e south of Ute F i e l d and s i x m i l e s south of t h e Wyoming-Montana s t a t e l i n e .

The f i e l d was discovered

i n 1968, and o i l i s produced from t h e Muddy Sandstone a t an average depth of 6,350 f e e t .

The a r e a covered by t h e Muddy Unit of Hunter Ranch

i s 1,554 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land.

The productive

a r e a of t h e r e s e r v o i r i s 1 , 0 8 1 a c r e s . The producing sand bodies of t h e Muddy Unit a t Hunter Ranch F i e l d a r e p a r t of a r e g i o n a l marine s h o r e l i n e system deposited on and a g a i n s t remnant h i g h a r e a s developed on t h e underlying S k u l l Creek Shale. sandstones of a l l 3 zones a r e very f i n e - t o fine-grained, pepper sands w i t h moderate t o h i g h c l a y c o n t e n t .

The

s a l t and

The hydrocarbon t r a p

i s s t r a t i g r a p h i c i n n a t u r e and l i m i t e d by sand pinchouts t o t h e e a s t and s o u t h , a p e r m e a b i l i t y b a r r i e r t o t h e n o r t h , and an oil-water c o n t a c t along t h e w e s t edge.

The r e s e r v o i r ' s primary producing mechanism i s

f l u i d expansion and s o l u t i o n gas d r i v e w i t h p o s s i b l e water d r i v e support on t h e w e s t edge where t h e r e s e r v o i r i s i n apparent h y d r a u l i c communication w i t h a downdip a q u i f e r .

Ultimate recovery of o i l from

t h e Muddy r e s e r v o i r i s estimated t o be about 30 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e w i t h secondary recovery supplying n e a r l y 45 p e r c e n t of t h e t o t a l recovery.

Average p o r o s i t y and p e r m e a b i l i t y according t o w e l l

l o g d a t a , w e l l p r o d u c t i v i t y and d r i l l stem information from t h e Muddy sands, a r e 19.5 p e r c e n t and 47 m i l l i d a r c i e s , r e s p e c t i v e l y . Water i n j e c t i o n i n t o t h e Muddy r e s e r v o i r s t a r t e d i n 1976, and i s s t i l l a c t i v e a t t h r e e w e l l s according t o December, 1979 d a t a .

The

7 cumulative volume of water i n j e c t e d i s 1,075,476 b a r r e l s (4.517 x 10 I n j e c t i o n water i s s u p p l i e d by t h e Fox H i l l s Sandstone and

gallons).

h a s been i n j e c t e d a t p r e s s u r e s ranging from vacuum t o 2,900 p s i .

Isenhour F i e l d (No production d a t a a v a i l a b l e ) Isenhour Unit

A s of January, 1980, Belco Petroleum Corporation had n o t y e t begun o p e r a t i o n of a t e r t i a r y o i l recovery p r o j e c t a t t h e Isenhour U n i t , Township 29 North, Range 112 West, S u b l e t t e County.

Plans f o r the

p r o j e c t c a l l f o r t h e i n j e c t i o n of a water/polymer s o l u t i o n i n t o t h e Almy "M-42"

sand.

Approval f o r t h e p r o j e c t was r e c e n t l y given by t h e U.S. Survey.

Geological

Three i n j e c t i o n w e l l s have been d r i l l e d and prepared f o r

i n j e c t i o n , which is expected t o begin w i t h i n t h e next few months.

J o e Creek F i e l d (1,269,420 b b l s o i l , 2,950,353 MCF g a s ; 1960-79) J o e Creek Unit J o e Creek F i e l d encompasses an a r e a of 1,544 a c r e s of f e d e r a l and p r i v a t e land i n t h e n o r t h e r n Powder River Basin, 3 m i l e s w e s t of Recluse F i e l d , and i n c l u d e s much of t h e a r e a i n Townships 56 and 57 North, Range 75 West, Campbell County.

The discovery w e l l was completed i n t h e

Muddy Sandstone i n 1969. The geometry of t h e r e s e r v o i r a t J o e Creek F i e l d s u g g e s t s non-marine point bar deposition.

I n g e n e r a l , t h e r e i s a complete f a c i e s change from

s i l t and s h a l e on t h e w e s t s i d e t o a t h i c k sand r e s e r v o i r on t h e e a s t . F u r t h e r t o t h e e a s t , t h e r e s e r v o i r sand t a p e r s o u t . Muddy r e s e r v o i r i s w e l l defined and continuous.

I n between, t h e

The c o n t a c t a t t h e

base of t h e Muddy r e s e r v o i r appears t o be an e r o s i o n a l unconformity. The hydrocarbon t r a p i s t h e r e s u l t of a sand pinchout a t t h e end of a t i d a l channel d e p o s i t o r i e n t e d i n a n o r t h e a s t e r l y , updip d i r e c t i o n . Production h i s t o r y i n d i c a t e s t h a t t h e r e s e r v o i r i n i t i a l l y produced by a s o l u t i o n gas d r i v e mechanism w i t h l i t t l e o r no i n f l u x of water.

Prior

t o t h e s t a r t of t h e w a t e r f l o o d , i t was estimated t h a t 22 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e had been recovered by water i n j e c t i o n .

Average

pay zone t h i c k n e s s of t h e Muddy r e s e r v o i r i s 29 f e e t w i t h an average p o r o s i t y of 12.2 p e r c e n t . Fresh water from t h e Fox H i l l s Sandstone and Lance Formation has been i n j e c t e d i n t o t h e Muddy r e s e r v o i r s i n c e t h e waterflood began i n 1975.

A s of December, 1979, a11 f o u r of t h e i n j e c t i o n w e l l s had been

7

t e m p o r a r i l y s h u t - i n , having i n j e c t e d 1,074,764 b a r r e l s (4.514 x 10

g a l l o n s ) of water a t average p r e s s u r e s ranging from 963 t o 2,336 p s i .

Joyce Creek F i e l d (170,230 b b l s o i l , 10,323,625 MCF gas; 1958-79) Dakota Unit The Dakota Unit of Joyce Creek F i e l d i s t h e s i t e of a one w e l l s a l t water d i s p o s a l system operated by H i l l i a r d O i l and Gas Company.

The

i n i t i a l i n j e c t i o n s of produced b r i n e from t h e Dakota sand occurred i n 1975.

Between t h e s t a r t of i n j e c t i o n and December, 1979, 141,378 b a r r e l s

(5,937,876 g a l l o n s ) of s a l t water were i n j e c t e d i n t o t h e Dakota sand a t a depth of 3,958 f e e t .

Average p o r o s i t y and p e r m e a b i l i t y of t h e

Dakota i n t h e Joyce Creek F i e l d a r e a a r e 17.4 percent and 140

millidarcies, respectively.

One a n a l y s i s of produced Dakota b r i n e

i n d i c a t e d a TDS c o n c e n t r a t i o n of 67,476 mg/l. Casing Record:

S a l t Water D i s p o s a l Well #23, T15N-R103W-8 bd, Joyce Creek F i e l d , Dakota U n i t , T o t a l Depth = 4075 f e e t .

Casing S i z e

( m t )

Wt.

Depth S e t

9-5/8"

32

529'

5-1/2"

15.5

4075'

2-3/8"

Cement circ. t o surface cement t o p a t 2620'

tubing

Kane F i e l d (805,418 b b l s o i l , 52,849 MCF g a s ; 1966-79) Minnelusa U n i t S a l t w a t e r d i s p o s a l t o t h e Minnelusa Formation a t Kane F i e l d began i n 1978, through a n i n j e c t i o n w e l l l o c a t e d i n S e c t i o n 9 , Township 57 The w e l l i s p e r f o r a t e d i n t h e

North, Range 70 West, Campbell County. Minnelusa a t a d e p t h of 8,394 f e e t . ranged between 500 and 550 p s i .

Average i n j e c t i o n p r e s s u r e s have

December, 1979, i n j e c t i o n r e p o r t s

i n d i c a t e t h a t 91,289 b a r r e l s (3,834,138 g a l l o n s ) of b r i n e have been injected since the project started. Casing Record:

S a l t Water D i s p o s a l Well #1, T57N-R70W-9 b d , Kane F i e l d , Minnelusa U n i t , T o t a l Depth = 8590 f e e t .

Casing S i z e

Wt.

(#/ft)

5-1/2"

17

5-1/2"

15.5

Depth S e t 0-110

'

1100-6400

'

Make

Cement

K-55

cement t o p a t 7500'

K-55

Keyhole F i e l d (8,315 b b l s o i l ; 1967) 16 S t a t e Unit Keyhole F i e l d was d i s c o v e r e d i n 1967, when a producing w e l l was completed i n t h e F a l l R i v e r Sandstone.

The f i e l d i s l o c a t e d i n Township

50 North, Range 66 West, Crook County.

The 16 S t a t e Unit i n v o l v e s a l l

s t a t e owned land on a 1 0 a c r e spacing schedule. Water I n j e c t i o n t o t h e F a l l River Sandstone s t a r t e d i n 1969, and one w e l l was s t i l l a c t i v e a s of January, 1979. s u p p l i e d by a w e l l i n t h e Lakota sand.

I n j e c t i o n water i s

Between t h e s t a r t of i n j e c t i o n

i n 1969, and t h e end of 1970, 8,955 b a r r e l s (376,110 g a l l o n s ) of water were i n j e c t e d .

The p r o j e c t resumed i n 1977, and through January, 1979,

an a d d i t i o n a l 13,345 b a r r e l s (560,490 g a l l o n s ) were i n j e c t e d .

Average

i n j e c t i o n p r e s s u r e s ranged from 275 t o 350 p s i . Casing Record :

Casing S i z e

I n j e c t i o n W e l l #7, T50N-R66W-16 acb, Keyhole F i e l d , 16 S t a t e Unit, T o t a l Depth = 577 f e e t .

Wt.

2-7 /811

(#/f t )

Hole S i z e

Depth S e t

Cement

Purpose

6-1/4"

564'

40 sacks

Injection

6.5

Kirby Creek F i e l d (627,694 b b l s o i l ; 1918-79) Kirby Creek Unit I n 1944, o i l was discovered i n t h e Permian age Phosphoria Formation of Kirby Creek F i e l d a t an average depth of about 3,400 f e e t .

Kirby

Creek F i e l d and t h e u n i t a r e a of t h e same name a r e l o c a t e d on t h e southe a s t f l a n k of t h e Bighorn Basin, approximately 120 m i l e s northwest of Casper i n Hot Springs County.

The u n i t p a r t i c i p a t i n g a r e a covers 941

a c r e s of f e d e r a l , s t a t e , and p r i v a t e land w i t h productive r e s e r v o i r underlying 772 a c r e s of t h e u n i t . S t r u c t u r a l l y , t h e f i e l d l i e s along t h e a x i s of t h e Zimmerman B u t t e a n t i c l i n e , an asymmetrical, elongated, northwest-southeast s t r u c t u r e w i t h about 350 f e e t of c l o s u r e .

trending

The Zimmerman B u t t e a n t i c l i n e

i s one of a s e r i e s of p a r a l l e l a n t i c l i n e s formed i n t h e v i c i n i t y of Kirby Creek d u r i n g t h e Laramide Revolution.

The Phosphoria Formation i s a w e l l f r a c t u r e d , d o l o m i t i c l i m e s t o n e w i t h an a v e r a g e e f f e c t i v e p o r o s i t y of 11.5 p e r c e n t .

Core a n a l y s e s

i n d i c a t e a m a t r i x p e r m e a b i l i t y of 2.4 m i l l i d a r c i e s , whereas, f r a c t u r e p e r m e a b i l i t y exceeds 1,000 m i l l i d a r c i e s .

An a v e r a g e e f f e c t i v e perme-

a b i l i t y t o o i l of 40 m i l l i d a r c i e s was c a l c u l a t e d u s i n g t h e r a d i a l flow equation.

The primary mechanism of p r o d u c t i o n i s a combination of

w a t e r d r i v e and expansion of r e s e r v o i r r o c k and f l u i d .

The f r a c t u r e d

n a t u r e of t h e r e s e r v o i r r o c k , h i g h o i l v i s c o s i t y and h i g h w a t e r s a t u r a t i o n make any t y p e of secondary r e c o v e r y p r o j e c t r i s k y . A p i l o t w a t e r i n j e c t i o n p r o j e c t w i t h one w e l l was i n i t i a t e d i n

8 1968, and 2,688,668 b a r r e l s (1.1292 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d by December, 1979.

I n j e c t i o n p r e s s u r e a v e r a g e s ranged from

980 t o 1,250 p s i .

K i r k Ranch F i e l d (935,688 MCF g a s ; 1954-79) Cloverly Unit The n a t u r a l g a s s t o r a g e p r o j e c t a t K i r k Ranch F i e l d , o p e r a t e d by Northern Gas Company, i s c u r r e n t l y (December, 1979) s h u t - i n .

The

s t o r a g e i n j e c t i o n w e l l s a r e l o c a t e d i n S e c t i o n s 6 and 7, Township 28 North, Range 92 West, and S e c t i o n 1, Township 28 North, Range 93 West, Fremont County.

The p r o j e c t s t a r t e d i n 1972, w i t h i n j e c t i o n t o t h e

C l o v e r l y Formation a t a d e p t h of about 2,500 f e e t .

No f u r t h e r d e t a i l s

were a v a i l a b l e on t h e g a s s t o r a g e p r o j e c t from t h e f i l e s of t h e O i l and Gas Commission.

Kuehne Ranch F i e l d (2,601,942 b b l s o i l , 21,324 MCF g a s ; 1965-79) Kuehne Ranch U n i t Kuehne Ranch F i e l d i n c l u d e s 480 a c r e s i n t h e n o r t h e a s t Powder R i v e r Basin on a p r o d u c t i v e s o u t h e a s t t o n o r t h w e s t t r e n d i n t h e PermoPennsylvanian Minnelusa F o r m a t i ~ n , w h i c h e x t e n d s from t h e P l e a s a n t V a l l e y Garner Lake a r e a on t h e s o u t h e a s t , t o Wallace F i e l d on t h e n o r t h west.

The Minnelusa d i s c o v e r y w e l l was completed i n 1965.

Average

d e p t h t o t h e p r o d u c t i v e upper Minnelusa zones i s approximately 7,950 feet.

Well d r i l l i n g a t Kuehne Ranch F i e l d followed a n 80-acre s p a c i n g

schedule. Hydrocarbon entrapment i s a r e s u l t of updip t r u n c a t i o n of t h e productive sands.

The primary producing mechanism of t h e Minnelusa

pay zones i s f l u i d expansion.

Core a n a l y s e s of t h e Minnelusa "B"

zone i n d i c a t e a n a v e r a g e p o r o s i t y and p e r m e a b i l i t y of 14.7 p e r c e n t and 64.1 m i l l i d a r c i e s , r e s p e c t i v e l y .

The "C"

zone h a s a n a v e r a g e p o r o s i t y

and p e r m e a b i l i t y of 13.8 p e r c e n t and 3 2 . 1 m i l l i d a r c i e s , r e s p e c t i v e l y . A secondary r e c o v e r y w a t e r f l o o d p r o j e c t s t a r t e d i n 1969.

1972, a second i n j e c t i o n w e l l was added.

In

Water i s o b t a i n e d from a supply

w e l l completed i n t h e Fox H i l l s Sandstone.

A s of December, 1979,

8 3,354,703 b a r r e l s (1.409 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d

through b o t h w e l l s s i n c e t h e w a t e r f l o o d began.

Average i n j e c t i o n

p r e s s u r e s d u r i n g t h a t p e r i o d ranged from 1,400 t o 3,150 p s i .

I n j e c t i o n W e l l #4, T51N-R70W-13 a b , Kuehne Ranch F i e l d Kuehne Ranch U n i t , T o t a l Depth = 8051 f e e t .

Casing Record: Casing S i z e 8-5 18" 5-1/2"

Wt.

(#/ft) 24

15.5,17

Hole S i z e

Depth S e t

Cement

Purpose

12-1/4"

234'

240 s a c k s

Surface

7-718"

8024'

300 s a c k s

Injection

Kuehne Ranch S o u t h e a s t U n i t The u n i t p a r t i c i p a t i n g a r e a a t Kuehne Ranch F i e l d S o u t h e a s t U n i t encompasses 1,240 a c r e s of f e d e r a l and p r i v a t e l a n d i n Township 5 1 North, Range 69 West, Campbell County.

The p r o d u c t i v e a r e a of t h e upper

Minnelusa r e s e r v o i r u n d e r l i e s about 846 a c r e s w i t h a n a v e r a g e t h i c k n e s s of 1 8 f e e t .

Average p o r o s i t y and p e r m e a b i l i t y w i t h i n t h e r e s e r v o i r a r e

15.8 p e r c e n t and 100 m i l l i d a r c i e s , r e s p e c t i v e l y .

The r e s e r v o i r

t e m p e r a t u r e i s 130°F. Water i n j e c t i o n began i n 1975, a t t h e S o u t h e a s t U n i t and i n j e c t i o n r e p o r t s show t h a t i t c o n t i n u e d u n t i l t h e l a t t e r p a r t of 1976.

By

January, 1977, t h e s o l e i n j e c t i o n w e l l had been s h u t - i n a f t e r i n j e c t i n g 7 745,402 b a r r e l s (3.1307 x 1 0 g a l l o n s ) of f r e s h Fox H i l l s Sandstone w a t e r i n t o t h e upper Minnelusa o i l r e s e r v o i r .

Injection pressures

averaged between 2,134 and 2 , 5 5 1 p s i d u r i n g t h a t p e r i o d . Casing Record:

I n j e c t i o n W e l l # I , T51N-R69W-19 abd, Kuehne Ranch F i e l d , S o u t h e a s t U n i t , ' ~ o t a lDepth = 8185 f e e t .

Casing S i z e

Wt.

5-1/2"

(#/ft)

15.5,17,19,20

Hole S i z e

Depth S e t

Cement

7-7/8"

8139 '

500 s a c k s

Kummerfeld F i e l d (8,498,335 b b l s o i l , 731,127 MCF g a s ; 1960-79) Minnelusa U n i t The Minnelusa U n i t of Kummerfeld F i e l d is l o c a t e d a b o u t 20 m i l e s e a s t - n o r t h e a s t of G i l l e t t e and comprises 1 , 0 4 0 a c r e s of f e d e r a l and p r i v a t e land.

P r o d u c t i o n from t h e Minnelusa Formation was f i r s t

e s t a b l i s h e d i n 1969.

The o i l p r o d u c t i v e Minnelusa "Bit sand i s composed

of c l e a r , f i n e - g r a i n e d , w e l l t o moderately cemented s a n d s t o n e .

Esti-

mated f i e l d a v e r a g e p o r o s i t y and p e r m e a b i l i t y a r e 17 p e r c e n t and 208

millidarcies, respectively.

The "B"

r e s e r v o i r i s bounded by a p o r o s i t y

pinchout t o t h e n o r t h , s o u t h , and e a s t , and by an o i l - w a t e r c o n t a c t on t h e west and southwest s i d e s .

The primary producing mechanism i s

f l u i d and r o c k expansion w i t h some a d d i t i o n a l r e s e r v o i r energy c o n t r i buted by s o l u t i o n g a s d r i v e and w a t e r encroachment from t h e southwest. I n 1973, a l i n e d r i v e t y p e w a t e r i n j e c t i o n p r o j e c t began.

Fresh

w a t e r from t h e Fox H i l l s Sandstone and produced Minnelusa Formation w a t e r are i n j e c t e d i n t o t h e Minnelusa "B1' r e s e r v o i r a t a v e r a g e p r e s s u r e s r a n g i n g from 643 t o 2,364 p s i .

December, 1979 d a t a i n d i c a t e d t h a t 5

w e l l s were a c t i v e l y i n j e c t i n g and t h a t a cumulative t o t a l of 7,659,659 8 b a r r e l s (3.2171 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d up t o t h a t time

. Kummerfeld F i e l d a l s o u t i l i z e s a two w e l l w a t e r d i s p o s a l system.

S t a r t e d i n 1974, w i t h a w e l l p e r f o r a t e d i n t h e Lakota Sandstone, t h e system i s used t o d i s p o s e of b r i n e s produced w i t h o i l from t h e Minnelusa Formation.

Another w e l l which i n j e c t s b r i n e t o t h e Minnelusa Formation

was added i n 1978.

8 A s of J u l y , 1979, 3,151,869 b a r r e l s (1.3238 x 1 0

g a l l o n s ) of s a l t w a t e r had been i n j e c t e d through t h e Lakota w e l l a l o n e . I n j e c t i o n d a t a f o r t h e Minnelusa w e l l were n o t a v a i l a b l e . Casing Record:

Casing S i z e

I n j e c t i o n Weld #A-1-32, T51N-R68W-32 abb, Kummerfeld F i e l d , Minnelusa U n i t , T o t a l Depth = 7698 f e e t . Wt.

(#/ft)

8-5 /8"

24

5-112"

15.5,17

Hole S i z e

Depth S e t

Cement

Purpose

12-114"

245 '

210 s a c k s

Surface

7-7 / 8"

7697'

300 s a c k s

Injection

Water Q u a l i t y A n a l y s i s

Cations

(ppd 18,673

Na

480

K Ca

1,300

Mg

976

Fe

-

-

(Water sample from M n n e l u s a Formation a t producing w e l l #30-1, T41N-R68W-30 add, Kurnmerfeld F i e l d , Minnelusa U n i t , Depth of w e l l = 7730 f e e t , P e r f o r a t i o n s 7612-7616 feet. ) Anions S04 c12 HC03

(ppm) 5,465 30,000

TDS = 57,194 ppm

610 pH = 6.7

-

H2S

LaBarge F i e l d (20,213,281 b b l s o i l , 53,663,478 MCF g a s ; 1925-79) Almy U n i t O i l was d i s c o v e r e d i n t h e Almy r e s e r v o i r i n 1924, v i a a w e l l

completed a t a d e p t h of 560 t o 572 f e e t .

The Almy U n i t comprises

1 , 4 0 0 a c r e s of f e d e r a l and p r i v a t e l a n d .

The p r i n c i p a l producing zone,

between 650 and 1 , 1 0 0 f e e t , may b e d i v i d e d i n t o f o u r d i s t i n c t s a n d s . The f i r s t i s a p e r s i s t e n t , 20-foot t h i c k sand and t h e o t h e r t h r e e make up a lower series of t h r e e s a n d s t o n e s t h a t v a r y g r e a t l y i n t h i c k n e s s and p e r s i s t e n c e . Some hydrocarbon t r a p s e p a r a t i o n i n t h e f i e l d i s b e l i e v e d t o have r e s u l t e d from minor t h r u s t f a u l t i n g a s s o c i a t e d w i t h t h e H i l l i a r d f a u l t t o t h e west.

The Almy U n i t i s s i t u a t e d on t h e s o u t h h i g h of a l o n g ,

narrow, n o r t h - s o u t h t r e n d i n g a n t i c l i n e w i t h two d i s t i n c t h i g h s .

About

two m i l e s w e s t of and p a r a l l e l t o t h e a n t i c l i n e i s t h e Dasby f a u l t , a major t h r u s t f a u l t of southwest Wyoming w i t h a n e s t i m a t e d s t r a t i g r a p h i c d i s p l a c e m e n t of 43,000 f e e t i n LaBarge Mountain.

P r e d i c t i o n of o i l

p r o d u c t i v e r e s e r v o i r s i s extremely d i f f i c u l t due t o t h e v a r i a b i l i t y i n t r a p c o n d i t i o n s r e s u l t i n g from t h e t h r u s t i n g .

The primary r e s e r v o i r

energy i s provided by s o l u t i o n g a s and expansion of s m a l l g a s c a p s a l o n g t h e c r e s t of t h e s t r u c t u r e . The Almy U n i t was approved i n 1949, w i t h Texaco, I n c . a s o p e r a t o r . A p i l o t w a t e r f l o o d s t a r t e d i n 1961, and was expanded t o a f u l l s c a l e

Of 115 e x i s t i n g i n j e c t i o n w e l l s , 80 have been s h u t - i n

p r o j e c t i n 1965.

a s of December, 1979.

Cumulative i n j e c t i o n f i g u r e s f o r t h e e n t i r e

9 w a t e r f l o o d p r o j e c t t o t a l e d 37,354,000 b a r r e l s (1.5689 x 1 0 g a l l o n s )

of f r e s h w a t e r from a s u p p l y w e l l i n t h e a l l u v i a l a q u i f e r and produced Almy sand w a t e r . I n 1977, a s a l t w a t e r d i s p o s a l w e l l (T26N-R113W-3

c ) began

i n j e c t i n g produced b r i n e s back i n t o t h e Almy sand a t a d e p t h of 966 feet.

I n j e c t i o n p r e s s u r e s have averaged between 700 and 850 p s i s i n c e

t h e p r o j e c t began.

Approximately 143,000 b a r r e l s (6,006,000 g a l l o n s )

of w a t e r have been d i s p o s e d of through t h e w e l l a s of December, 1979. A t e r t i a r y r e c o v e r y program was undertaken by Texaco, I n c . i n 1975,

w i t h t h e i n j e c t i o n of a w a t e r / s u r f a c t a n t m i x t u r e through f o u r w e l l s i n t h e Almy s a n d . Casing Record:

I n j e c t i o n W e l l #D134, T27N-R113W-34 b c a , LaBarge F i e l d , Almy U n i t , T o t a l Depth = 1255 f e e t .

Casing S i z e

Wt.

4-1/2"

(#/ft)

10.5,11.6

2-3/8"

Hole S i z e

Depth S e t

7-5/8"

1224 '

Cement 450 s a c k s

1109 '

E a s t LaBarge F i e l d (444,764 b b l s o i l , 36,519,966 MCF g a s ; 1957-79) E a s t LaBarge U n i t E a s t LaBarge F i e l d i s l o c a t e d i n Township 27 North, Range 112 West, S u b l e t t e and L i n c o l n c o u n t i e s .

A secondary r e c o v e r y w a t e r f l o o d p r o j e c t

s t a r t e d i n 1975, through one w e l l .

I n j e c t i o n i n t o t h e Almy sand between

7 1975 and December, 1979, t o t a l e d 584,409 b a r r e l s (2.4545 x 1 0 g a l l o n s ) of f r e s h and produced w a t e r from a n a l l u v i a l w e l l n e a r t h e Green River and from t h e Almy s a n d , r e s p e c t i v e l y .

Average i n j e c t i o n p r e s s u r e s have

ranged from 2,200 t o 2,500 p s i d u r i n g t h a t p e r i o d . Casing Record :

I n j e c t i o n W e l l #R-2, T27N-R112W-29 ad (bc) , E a s t LaBarge F i e l d , E a s t LaBarge U n i t , T o t a l Depth = 2843 f e e t .

Casing S i z e

Wt.

8-5 / 8" 4-1/2"

( m t )

Amount

Perforations

Purpose

24

239'

Surface

9.5

2426'

2669-2671'

Injection

11.6

416 '

2690-2692'

Injection

North LaBarge F i e l d (690,020 b b l s o i l , 84,773,964 MCF g a s ; 1958-79) Saddle Ridge Unit O i l w a s d i s c o v e r e d a t North LaBarge F i e l d i n 1960, when Belco

Petroleum C o r p o r a t i o n completed a w e l l i n t h e 5 t h Mesaverde sand.

The

Saddle Ridge U n i t was e s t a b l i s h e d i n 1963, and comprises 2,680 a c r e s i n Townships 27 and 28 North, Range 113 West, S u b l e t t e County. The 5 t h Mesaverde sand r e s e r v o i r c o n s i s t s of a massive Cretaceous s a n d s t o n e w i t h some i n t e r b e d d e d s h a l e l e n s e s . i s a t h i c k c o n t i n u o u s s h a l e member.

Overlying t h e s a n d s t o n e

Structurally, the reservoir is

p a r t of a symmetrical a n t i c l i n e 1 . 5 m i l e s long and .5 m i l e s wide a t t h e n o r t h end of t h e l a r g e r LaBarge a n t i c l i n e .

The p r o d u c t i v e a r e a of

t h e r e s e r v o i r c o v e r s about 350 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of 30 f e e t . Water i n j e c t i o n began i n 1967, w i t h w a t e r o b t a i n e d from p r o d u c t i o n w e l l s i n t h e Mesaverde Formation.

A s of December, 1979, 7 of 8 e x i s t i n g

i n j e c t i o n w e l l s remained a c t i v e and a cumulative t o t a l of 4,646,003

8 b a r r e l s (1.9513 x 10 g a l l o n s ) of water had been i n j e c t e d t o t h e 5 t h Mesaverde zone.

Average i n j e c t i o n p r e s s u r e s have ranged from 700 t o

1,960 p s i . North LaBarge F i e l d i s a l s o t h e s i t e of a water d i s p o s a l w e l l completed i n t h e Almy sand a t a depth of 1,316 f e e t .

Between t h e

s t a r t i n g d a t e of t h e d i s p o s a l p r o j e c t and December, 1979, 20,388 b a r r e l s (856,296 g a l l o n s ) of produced b r i n e have been i n j e c t e d t o t h e Almy sand. Casing Record:

I n j e c t i o n Well 82-4, T27N-R113W-4 bba, North LaBarge F i e l d , Saddle Ridge U n i t , T o t a l Depth = 2080 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5 18"

24

5-1/2"

14

Hole S i z e

11" 7-7/8"

Depth S e t

Cement

157 '

85 sacks

2080 '

235 sacks

Lance Creek F i e l d (105,121,400 b b l s o i l , 140,313,523 MCF gas; 1918-79) The Lance Creek F i e l d i s l o c a t e d j u s t west of t h e c e n t e r of Niobrara County, approximately 30 m i l e s west of t h e t r i - s t a t e borders of Wyoming, South Dakota, and Nebraska. O i l was discovered a t Lance Creek F i e l d i n 1918, when a w e l l was

completed i n t h e Wall Creek sand.

O i l was l a t e r found i n t h e Dakota,

Muddy, Lakota, and Sundance r e s e r v o i r s , and i n t h e Leo and Converse sands of t h e Minnelusa Formation. S t r u c t u r a l l y , t h e Lance Creek a r e a i s p a r t of an e l o n g a t e d , curved, asymmetric f o l d which l i e s i n t h e s o u t h e a s t corner of t h e Powder River Basin and occupies t h e west end of an a n t i c l i n a l a x i s t h a t extends twelve m i l e s t o t h e e a s t .

The f i e l d i s d i v i d e d a r e a l l y i n t o e a s t and

west p o r t i o n s by s t r u c t u r a l and l i t h o l o g i c a l anomalies.

A n a t u r a l gas s t o r a g e p r o j e c t a t Lance Creek u t i l i z e s t h e Dakota

reservoir.

A s of December, 1979, only one of e i g h t s t o r a g e w e l l s

remained a c t i v e .

F u r t h e r d e t a i l s on t h e p r o j e c t were n o t a v a i l a b l e f o r

t h i s report.

Lance Creek OPC Sundance Unit The Lance Creek OPC Sundance Unit covers an a r e a of 958 a c r e s of f e d e r a l and s t a t e owned land i n w e s t - c e n t r a l Niobrara County. discovered i n t h e b a s a l Sundance Formation i n 1918.

O i l was

The o r i g i n a l

mechanisms of production were s o l u t i o n gas d r i v e and l i m i t e d n a t u r a l water d r i v e .

The average pay zone t h i c k n e s s of t h e OPC r e s e r v o i r i s 26

f e e t w i t h an average p o r o s i t y of 14 p e r c e n t . The C o n t i n e n t a l O i l Company began a three-well p i l o t waterflood p r o j e c t i n t h e e a s t end of t h e r e s e r v o i r during 1960.

The p i l o t was

expanded i n 1961, t o a f u l l s c a l e p e r i p h e r a l f l o o d p a t t e r n over an a r e a Water f o r t h e i n j e c t i o n p r o j e c t was produced

of about 300 a c r e s .

water from t h e Leo and Dakota sands, which was purchased from t h e Marathon O i l Company. The l a s t y e a r of a c t i v e i n j e c t i o n i n t h e u n i t was 1972.

A s of

January, 1979, t h e r e were e l e v e n s h u t - i n i n j e c t o r s i n t h e OPC Unit. Cumulative i n j e c t i o n i n t o t h e r e s e r v o i r i s 8,614,352 b a r r e l s (3.6180 8 x 10 g a l l o n s ) of w a t e r .

Muddy Unit The Muddy Unit of Lance Creek F i e l d i n c l u d e s 450 a c r e s of f e d e r a l and p r i v a t e land.

The Muddy r e s e r v o i r covers 500 a c r e s and h a s an

average pay zone t h i c k n e s s of 10 t o 20 f e e t . v o i r i s p a r t of a f a u l t e d a n t i c l i n e .

Structurally, the reser-

F a u l t i n g l i m i t s production on t h e

e a s t s i d e of t h e u n i t .

Average p o r o s i t y and p e r m e a b i l i t y f i g u r e s from

1918 c o r e a n a l y s e s were 17 p e r c e n t and 20 m i l l i d a r c i e s , r e s p e c t i v e l y . Water i n j e c t i o n was i n i t i a t e d i n 1960, 42 y e a r s a f t e r t h e discovery of o i l i n t h e Muddy r e s e r v o i r .

Produced water from t h e Leo sands was

used i n a p e r i p h e r a l waterflood of t h e u n i t u n t i l 1973, when i n j e c t i o n was h a l t e d and w e l l s were shut-in.

There i s a proposal t o begin a new

water i n j e c t i o n p r o j e c t i n t h e Muddy which would sweep o i l from t h e s o u t h e a s t p o r t i o n of t h e r e s e r v o i r . Morrison Unit The Lance Creek Morrison Unit covers an a r e a of 198.7 acres--

63.7 a c r e s of f e d e r a l l y owned land and 135 a c r e s of p r i v a t e l y owned land.

The Morrison r e s e r v o i r i n c l u d e s 179 a c r e s of pay zone sands t h a t

average 21 f e e t i n t h i c k n e s s . r e s e r v o i r i s 11 p e r c e n t . millidarcies. water d r i v e .

The average p o r o s i t y of t h e Morrison

P e r m e a b i l i t y w i t h i n t h e sand v a r i e s from 0-400

O r i g i n a l r e s e r v o i r energy was provided by a n a t u r a l O i l was discovered i n a J u r a s s i c sandstone i n 1955,

a n d , w i t . h t h e a i d of secondary recovery techniques, was s t i l l producing o i l a s of December, 1979. The Morrison w a t e r f l o o d p r o j e c t began i n J u l y , 1959, w i t h two i n j e c t i o n wells.

A t h i r d w e l l was added l a t e r .

The source of water

used i n t h e i n j e c t i o n p r o j e c t i s t h e Leo sand, which c o n s i s t s of i n t e r bedded l a y e r s of sand and dolomite w i t h some c h e r t .

F i r s t Sundance Unit A v a i l a b l e d a t a on t h e F i r s t Sundance Unit of Lance Creek F i e l d a r e limited.

The F i r s t Sundance r e s e r v o i r i n c l u d e s an a r e a of 455 a c r e s

and h a s an average pay zone t h i c k n e s s of 25 f e e t .

Water i n j e c t i o n began i n 1960, and continued i n t o 1963.

Eight

w e l l s were a c t i v e during t h a t time and i n j e c t e d a cumulative t o t a l of

1,301,296 b a r r e l s (54,654,432 g a l l o n s ) of water. T y p i c a l l y , w e l l s completed i n t h e f i r s t Sundance r e s e r v o i r employ t h e following c a s i n g schedule t o p r o t e c t t h e w e l l and p e n e t r a t e d format i o n s from p o s s i b l e contamination:

Casing Record:

I n j e c t i o n Well 0. Rohlff #15, T36N-R65W-32 c c a , Lance Creek F i e l d , F i r s t Sundance U n i t , T o t a l Depth = 3628 f e e t .

Casing S i z e

Amount

Cement

Perf o r a t i o n s

154 '

85 sacks

2855-2870'

7"

3502'

125 sacks

3560-3618'

5"

186'

10-3/4"

-

-

Basal Sundance Unit O i l production from t h e Basal Sundance Unit of Lance Creek F i e l d

began i n 1935.

The h i s t o r y of production, s i n c e 1935, has shown an

expansion of t h e g a s cap and a slow d e c l i n e i n both r e s e r v o i r p r e s s u r e and r a t e of production. A p i l o t waterflood p r o j e c t began i n 1952, w i t h p e r i p h e r a l f l o o d i n g

of t h e b a s a l Sundance r e s e r v o i r , and was expanded t o a 20-well i n j e c t i o n system by 1962.

Water f o r i n j e c t i o n purposes was obtained from producing

w e l l s i n t h e Leo sand member of t h e Minnelusa Formation.

The most

r e c e n t r e p o r t e d i n j e c t i o n s occurred i n 1969, and brought t h e cumulative t o t a l of water i n j e c t e d s i n c e t h e p r o j e c t began t o 27,917,230 b a r r e l s 9 (1.1725 x 10 g a l l o n s ) . The b a s a l Sundance r e s e r v o i r covers an a r e a of 1,715 a c r e s w i t h an estimated pay horizon t h i c k n e s s of 64 f e e t .

Core a n a l y s e s of pay

zone sand between 4,000 and 4,020 f e e t below t h e s u r f a c e y i e l d e d an average p o r o s i t y of 21 p e r c e n t and an average p e r m e a b i l i t y of 338 millidarcies.

Leo Sand Unit I n i t i a l water i n j e c t i o n s i n t o t h e Leo sand r e s e r v o i r of Lance Creek F i e l d occurred i n 1962, through two w e l l s which were temporarily s h u t - i n a s of 1979.

The i n j e c t i o n program was i n i t i a t e d t o supplement

d e c l i n i n g r e s e r v o i r p r e s s u r e which was o r i g i n a l l y provided by a n a t u r a l water d r i v e .

Water used f o r i n j e c t i o n purposes was supplied by producing

w e l l s i n t h e Leo sand r e s e r v o i r . Casing Record:

I n j e c t i o n Well C a r r i e Putnam #18, T35N-R65W-4, Lance Creek F i e l d , Leo Sand U n i t , T o t a l Depth = 5465 f e e t . Casing S i z e

Amount

Cement

2 8 0 r , 7"

175 sacks

7I'

5368', 8"

500 sacks

2-1/2"

5453 '

11-3 14"

F i r s t Converse Unit The Permian Converse sand member of t h e Minnelusa Formation has an e f f e c t i v e pay zone t h i c k n e s s of 30 f e e t .

Average p o r o s i t y and

p e r m e a b i l i t y of t h e Converse r e s e r v o i r a r e 16 p e r c e n t and 3 m i l l i d a r c i e s , respectively.

O i l was discovered i n t h e Converse sand i n 1936.

A water i n j e c t i o n p r o j e c t , which e v e n t u a l l y expanded t o s i x w e l l s ,

was u t i l i z e d f o r p r e s s u r e maintenance w i t h i n t h e r e s e r v o i r .

Water f o r

t h e p r o j e c t was obtained from producing w e l l s i n t h e Leo r e s e r v o i r . A s of 1979, a l l of t h e i n j e c t o r s were temporarily shut-in.

Lander F i e l d (8,381,577 b b l s o i l , 1909-79) Phosphoria Unit Lander F i e l d i s s i t u a t e d on a narrow, north-south t r e n d i n g a n t i c l i n e i n S e c t i o n s 1 3 , 24, and 25, Township 2 South, Range 1 E a s t , and S e c t i o n s 19 and 30, Township 2 South, Range 2 E a s t of t h e Wind River I n d i a n Reservation and i n S e c t i o n 4, Township 33, North, Range 99 West, Fremont County.

The Phosphoria Unit p a r t i c i p a t i n g a r e a comprises

562.55 a c r e s of t r i b a l I n d i a n l a n d , 469.31 a c r e s of a l l o t t e d I n d i a n land and 396.46 a c r e s of p r i v a t e l y owned f e e land.

The discovery w e l l

a t Lander F i e l d was completed i n t h e Phosphoria Formation i n 1909. S t r u c t u r a l l y , t h e f i e l d l i e s along t h e Lander a n t i c l i n e , t h e major l i n e of f o l d i n g t h a t i n c l u d e s t h e D a l l a s and Derby Dome f i e l d s t o t h e southeast.

The t o t a l c l o s u r e of t h e a n t i c l i n e i s a t l e a s t 1,500 f e e t .

A p i l o t waterflood p r o j e c t was approved i n 1964, using produced water from t h e Tensleep Sandstone.

Thirty-one of 36 i n j e c t i o n w e l l s

were a c t i v e l y i n j e c t i n g a s of December, 1979, when t h e cumulative volume of water i n j e c t e d s i n c e t h e p r o j e c t s t a r t e d was 29,173,151 b a r r e l s 9 (1.2253 x 10 g a l l o n s )

.

Casing Record:

I n j e c t i o n Well 1'60, T33N-R99W-4 dca, Lander F i e l d , Phosphoria U n i t , T o t a l Depth = 1900 f e e t .

Casing S i z e

Wt. ( # / f t )

Hole S i z e

13-3 /8"

38

17-1/2"

43'

30 sacks

8-5 / 8"

24

12-1/4"

180'

200 sacks

7-7/8"

1899'

550 sacks

5-1/2"

14,15.5

Depth S e t

Cement

Casing Record:

I n j e c t i o n W e l l #123, T2S-R2E-30 bba, Lander F i e l d , Phosphoria U n i t , T o t a l Depth = 1865 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

8-5/8"

24

12-1/4"

213 '

200 s a c k s

5-1/2"

14

7-7/8"

1523 '

260 s a c k s

Lazy "B"

F i e l d (1,124,238 b b l s o i l , 3,643,373 MCF g a s ; 1969-79)

Muddy U n i t Lazy "B"

F i e l d was i n i t i a l l y developed i n 1969, f o l l o w i n g t h e

completion of t h e d i s c o v e r y w e l l i n t h e Muddy Sandstone.

The f i e l d i s

l o c a t e d approximately t e n m i l e s west of G i l l e t t e and i n c l u d e s 3,953 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d c a l l e d t h e Muddy U n i t . The Lower Cretaceous Muddy Sandstone i s found a t a n a v e r a g e d e p t h of 9,670 f e e t and d i p s t o t h e southwest a t about 100 f e e t p e r m i l e . Compositionally, t h e Muddy c o n s i s t s of i n t e r b e d d e d s a n d s t o n e , s i l t s t o n e and s h a l e , r a n g i n g i n t h i c k n e s s from LOO t o 130 f e e t i n t h e Lazy "B" Field area.

Fifty-two c o r e samples a t t h e Muddy r e s e r v o i r were analyzed

and i n d i c a t e d a n a v e r a g e p o r o s i t y of 13.6 p e r c e n t .

Average c o r e

p e r m e a b i l i t y t o a i r i s 1 4 . 1 m i l l i d a r c i e s w i t h a maximum of 115 m i l l i darcies.

Estimated t e m p e r a t u r e of t h e r e s e r v o i r i s 2 2 0 ' ~ .

Primary

p r o d u c t i o n from t h e r e s e r v o i r i s c o n t r o l l e d by s o l u t i o n g a s d r i v e energy.

A s m a l l g a s cap i s a l s o p r e s e n t w i t h i n t h e Muddy sand.

I n j e c t i o n of f r e s h w a t e r from t h e Fox H i l l s Sandstone and Lance Formation i n t o t h e Muddy Sandstone r e s e r v o i r s t a r t e d i n 1975.

Five

a c t i v e i n j e c t i o n w e l l s a t t h e Muddy U n i t had i n j e c t e d a cumulative volume of 3,848,343 b a r r e l s (1.6163 x 1 08 g a l l o n s ) of w a t e r as of December, 1979.

Through t h e d u r a t i o n of t h e p r o j e c t , i n j e c t i o n p r e s s u r e s

have averaged between 500 and 2,525 p s i a t t h e wellhead.

L i g h t n i n g Creek F i e l d (2,223,236 b b l s o i l , 863,205 MCF g a s ; 1949-79) Newcastle U n i t L i g h t n i n g Creek F i e l d i s s i t u a t e d on a b r o a d , east-west t r e n d i n g a n t i c l i n a l n o s e which p l u n g e s westward a t 7.5 d e g r e e s a b o u t s i x m i l e s southwest of Lance Creek F i e l d i n N i o b r a r a County.

The d i s c o v e r y w e l l

was d r i l l e d t o t h e b a s a l Sundance Formation i n 1949.

I n A p r i l , 1951,

a n o i l producing w e l l was completed i n t h e Newcastle Sandstone, t h e t o p of which was logged a t 1,447 f e e t .

The 1,577 a c r e p r o d u c t i v e a r e a

of t h e Newcastle r e s e r v o i r was u n i t i z e d i n 1965, as a p i l o t o p e r a t i o n by Marathon O i l Company. The hydrocarbon t r a p of t h e Newcastle sand a t L i g h t n i n g Creek F i e l d i s formed by a n updip sand p i n c h o u t and a n a p p a r e n t o i l - w a t e r c o n t a c t a l o n g t h e downdip p r o d u c t i v e boundary.

The downdip w a t e r t a b l e

h a s remained v i r t u a l l y s t a t i o n a r y d u r i n g t h e p r o d u c t i v e l i f e of t h e f i e l d and no encroachment i n t o t h e producing a r e a i s e v i d e n t .

The

extreme s o u t h e r n l i m i t of t h e f i e l d i s c o n t r o l l e d by a l o s s of permea b i l i t y i n t h e sand a s a r e s u l t of c l a y f i l l i n g .

O i l expansion d r i v e

was t h e p r i n c i p a l s o u r c e of r e s e r v o i r energy d u r i n g primary p r o d u c t i o n . However, when coupled w i t h t h e low p e r m e a b i l i t y of t h e r e s e r v o i r , t h e o i l expansion energy was i n s u f f i c i e n t t o p r o v i d e a d e q u a t e n a t u r a l production.

To i n c r e a s e t h e r e s e r v o i r ' s p r o d u c t i v i t y , sand f r a c t u r i n g

was n e c e s s a r y f o r n e a r l y a l l of t h e w e l l s i n a d d i t i o n t o t h e commencement of a w a t e r i n j e c t i o n p r o j e c t i n t h e Newcastle Formation. The Newcastle r e s e r v o i r i s composed of a h a r d , f i n e - g r a i n e d ,

silty

t o s h a l e y sand which v a r i e s i n t h i c k n e s s from 0 t o 1 2 f e e t of n e t f l o o d a b l e sand.

Average p o r o s i t y and p e r m e a b i l i t y of t h e Newcastle

a r e 19.5 p e r c e n t and 1 0 m i l l i d a r c i e s , r e s p e c t i v e l y .

The r e s e r v o i r

i n c l u d e s o n l y 600 a c r e s of t h e u n i t p a r t i c i p a t i n g a r e a . The Newcastle U n i t w a t e r f l o o d began i n November, 1964, w i t h two injection wells.

Water f o r t h e p r o j e c t i s o b t a i n e d from a s u r f a c e

runoff pond and from a w e l l completed i n t h e White R i v e r Formation a t a d e p t h of 350-400 f e e t .

During t h e f i r s t n i n e y e a r s of t h e p r o j e c t ,

8 4,222,579 b a r r e l s (1.7735 x 1 0 g a l l o n s ) of f r e s h and produced w a t e r

were i n j e c t e d i n t o t h e Newcastle Sandstone. have ranged from 135 t o 900 p s i .

Average i n j e c t i o n p r e s s u r e s

W e l l i n j e c t i o n d a t a were n o t on f i l e

a t t h e O i l and Gas Commission f o r r e p o r t s a f t e r J a n u a r y , 1974.

L i t t l e B u f f a l o Basin F i e l d (83,598,844 b b l s o i l , 115,733,562 MCF g a s ; 1914-79) Tensleep U n i t L i t t l e B u f f a l o Basin F i e l d i s l o c a t e d on t h e southwest f l a n k of t h e Bighorn Basin i n Townships 47 and 48 North, Range 100 West, P a r k County, and Township 47 North, Range 99 West, Hot S p r i n g s County.

Gas was

d i s c o v e r e d i n t h e F r o n t i e r Formation between 1,750 and 1,792 f e e t i n November, 1914. covered i n 1943. Formation.

O i l p r o d u c t i o n from t h e Tensleep Sandstone w a s d i s -

I n September, 1944, o i l was d i s c o v e r e d i n t h e Phosphoria

The f i e l d was u n i t i z e d i n 1931.

S t r u c t u r a l l y , t h e f i e l d i s s i t u a t e d a t o p two e l l i p t i c a l domes (East and West B u f f a l o domes) of an asymmetrical, north-south c l i n e which encompasses 1,500 p r o d u c t i v e s u r f a c e a c r e s .

trending antiFive reservoirs

on t h e s t r u c t u r e produce hydrocarbons. The Tensleep Sandstone r e s e r v o i r a t L i t t l e B u f f a l o Basin F i e l d h a s a v e r a g e p o r o s i t y and p e r m e a b i l i t y of 14 p e r c e n t and 61.3 m i l l i d a r c i e s ( a i r permeability), respectively.

However, t h e r e s e r v o i r i s q u i t e

heterogeneous and p e r m e a b i l i t y r a n g e s from 0 t o 1 , 1 5 0 m i l l i d a r c i e s .

As

a r e s u l t , primary p r o d u c t i o n from t h e Tensleep r e s e r v o i r l e f t numerous p o c k e t s of u n d e p l e t e d , t i g h t , r e s e r v o i r rock. Secondary r e c o v e r y by g a s i n j e c t i o n s t a r t e d i n June, 1958.

A

w a t e r i n j e c t i o n p r o j e c t began i n A p r i l , 1966, u s i n g produced w a t e r from t h e Embar and Tensleep r e s e r v o i r s .

Of t h e 58 e x i s t i n g i n j e c t i o n w e l l s

(1979 d a t a ) , 12 a r e i n j e c t i n g w a t e r i n t o b o t h t h e Embar and Tensleep r e s e r v o i r s , 25 are i n j e c t i n g g a s i n t o b o t h r e s e r v o i r s , s i x a r e i n j e c t i n g g a s t o t h e Tensleep and 1 5 a r e i n j e c t i n g w a t e r i n t o t h e Tensleep. F i f t y of t h e w e l l s were s t i l l a c t i v e a s of December, 1979, though s t a t u s changes occur q u i t e f r e q u e n t l y a s a f u n c t i o n of f i e l d p r o d u c t i o n . Recent i n j e c t i o n r e p o r t s (December, 1979) i n d i c a t e t h a t 115,633,559 9 b a r r e l s (5.6158 x 1 0 g a l l o n s ) of w a t e r have been i n j e c t e d s i n c e t h e w a t e r f l o o d began.

I n j e c t i o n p r e s s u r e s have averaged between 140 and

1,915 p s i during t h a t t i m e .

Casing Record:

I n j e c t i o n W e l l #57, T47N-R100W-12 dbc, L i t t l e B u f f a l o Basin F i e l d , Tensleep U n i t , T o t a l Depth = 4807 f e e t .

Casing S i z e

Wt.

10-3/4"

7"

(#/ft)

32.75 20

Hole S i z e 15" 8-3/4"

Depth S e t

Cement

314 '

300 s a c k s

4806 '

175 (1st 425 (2nd

sacks stage) sacks stage)

Embar U n i t The Embar U n i t a t L i t t l e B u f f a l o Basin F i e l d i s l o c a t e d i n Township 47 North, Ranges 99 and 100 West, Hot S p r i n g s County.

I n September,

1944, o i l was d i s c o v e r e d i n t h e Embar (Phosphoria) Formation. Water i n j e c t i o n i n t o t h e Embar r e s e r v o i r began i n 1972.

A s of

December, 1979, 43 i n j e c t i o n w e l l s had been i n o p e r a t i o n s i n c e t h e

project started.

Thirty-two of t h o s e w e l l s a r e s t i l l a c t i v e .

Sixteen

i n j e c t o r s are c a p a b l e of d u a l w a t e r i n j e c t i o n t o t h e Embar and Tensleep reservoirs.

Eleven w e l l s are equipped f o r d u a l w a t e r and g a s i n j e c t i o n

and s i x w e l l s a r e s t r i c t l y g a s i n j e c t o r s t o t h e Embar r e s e r v o i r .

By

9 t h e end of 1979, a c u m u l a t i v e t o t a l of 31,864,186 b a r r e l s (1.3383 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d through a l l of t h e i n j e c t i o n w e l l s . Cumulative d a t a on g a s i n j e c t i o n w e l l s were n o t a v a i l a b l e .

Until

October, 1979, t h e w a t e r f l o o d p r o j e c t u t i l i z e d f r e s h w a t e r from t h e Madison Limestone.

From November, 1979, t o t h e p r e s e n t , produced Embar

Formation and Tensleep Sandstone w a t e r was used. Casing Record:

Casing S i z e 10-3/4"

7"

I n j e c t i o n Well 11105, T47N-R99W-6 c c a , L i t t l e B u f f a l o Basin F i e l d , Embar U n i t , T o t a l Depth = 4905 f e e t . (#/ft)

Wt.

Amount

Perforations

Purpose

45

247 '

26

29'

4627-4742'

I nj e c t i o n

23

4895 '

4757-4808'

Injection

20

16.5'

,4822-4882'

Injection

Surf a c e

Northwest Dome U n i t A d u a l w a t e r i n j e c t i o n w e l l t o t h e Embar and Tensleep r e s e r v o i r s

was p u t i n t o o p e r a t i o n i n 1971.

The w e l l i s l o c a t e d i n t h e Northwest

Dome U n i t of L i t t l e B u f f a l o B a s i n F i e l d i n Township 47 North, Range 100 West, S e c t i o n 3 , Hot S p r i n g s County.

The Embar Formation and Tensleep Sandstone a r e encountered a t d e p t h s of 4,659 and 4 , 8 9 1 f e e t , r e s p e c t i v e l y .

Cumulative i n j e c t i o n between

8 1971 and December, 1979, amounted t o 4,240,619 b a r r e l s (1.7811 x 1 0 g a l l o n s ) of produced Embar/Tensleep w a t e r .

Average i n j e c t i o n p r e s s u r e s

ranged from 50 t o 2,250 p s i d u r i n g t h a t p e r i o d .

Casing Record:

I n j e c t i o n W e l l 812, T47N-R100W-3 a c ( a d ) , L i t t l e Buffalo Basin F i e l d , Northwest Dome U n i t , T o t a l Depth = 5150 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth Set

Cement

9-5/8"

43.5

12-1/4"

312 '

300 sacks

5-1/2"

15.5

7-7/8"

5147 '

175 sacks 450 sacks

L i t t l e M i t c h e l l Creek F i e l d (5,125,594 b b l s o i l , 18,247 MCF g a s ; 1967-79) Minnelusa Unit L i t t l e M i t c h e l l Creek F i e l d i s l o c a t e d along t h e e a s t f l a n k of t h e Powder River Basin, about 15 m i l e s northwest of Moorcroft, Wyoming. The Minnelusa Unit comprises 2,800 a c r e s of f e d e r a l (2,240 a c r e s ) , s t a t e (320 a c r e s ) , and p r i v a t e f e e (240 a c r e s ) land. The p r o d u c t i v e l i m i t s of t h e Minnelusa r e s e r v o i r a r e c o n t r o l l e d by an updip pinchout of porous sand which c o r r e l a t e s w i t h a t h i c k e n i n g of t h e Opeche Shale t o t h e n o r t h and e a s t .

The boundaries t o t h e south and

w e s t a r e d e f i n e d by t h e downdip oil-water c o n t a c t . I n 1969, i n j e c t i o n of f r e s h water from t h e Fox H i l l s Sandstone i n t o t h e Minnelusa Formation commenced through one w e l l .

No a d d i t i o n a l

w e l l s have been added t o t h e waterflood p r o j e c t s i n c e 1969.

According 8

t o December, 1979, i n j e c t i o n r e p o r t s , 5,597,881 b a r r e l s (2.3511 x 10 g a l l o n s ) of water had been i n j e c t e d through w e l l #13-14,l a t average p r e s s u r e s of 100 t o 600 p s i . Casing Record:

I n j e c t i o n Well #13-14,1, T52N-R69W-14 cb, L i t t l e M i t c h e l l Creek F i e l d , Minnelusa U n i t , T o t a l Depth 7623 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

-

10-3 / 4"

32.75

558'

4-1/2"

11.6,10.5

7618'

400 s a c k s

=

L i t t l e Sand Draw F i e l d (6,207,625 b b l s o i l ; 1949-79) Nelson U n i t A two w e l l s a l t w a t e r d i s p o s a l system s t a r t e d i n 1972, a t t h e Nelson U n i t of L i t t l e Sand Draw F i e l d , Township 44 North, Range 96

West, Hot S p r i n g s County. Sand Draw F i e l d is

B r i n e produced w i t h o i l from w e l l s a t L i t t l e

i n j e c t e d t o t h e ~ h o s ~ h o r Formation ia and Tensleep

Sandstone a t a d e p t h of about 5,836 f e e t .

Cumulative i n j e c t i o n through

b o t h w e l l s s i n c e t h e p r o j e c t began was 13,211,404 b a r r e l s (5.5488 x 8 1 0 g a l l o n s ) of b r i n e a s of December, 1979.

The maximum a v e r a g e

i n j e c t i o n p r e s s u r e was 380 p s i .

L o s t S o l d i e r F i e l d (181,554,016 b b l s o i l , 73,412,623 MCF g a s ; 1916-79) The L o s t S o l d i e r o i l and g a s f i e l d o c c u p i e s a h i g h l y f a u l t e d , s l i g h t l y e l l i p t i c a l dome a d j a c e n t t o and en e c h e l o n w i t h t h e w e s t end of t h e Wertz-Mahoney-Ferris

anticline.

The Mesaverde Formation forms

hogback escarpments t h a t surround p a r t of t h e f i e l d .

The N i o b r a r a

S h a l e i s exposed on t h e c r e s t of t h e s t r u c t u r e a t an average e l e v a t i o n of 6,900 f e e t .

The L o s t S o l d i e r dome h a s a n independent c l o s u r e of

approximately 3,500 f e e t .

Dips on t h e basinward southwest f l a n k r e a c h

45 d e g r e e s , w h i l e on t h e mountainward n o r t h e a s t f l a n k , d i p s r e a c h a maximum of 35 d e g r e e s .

L o s t S o l d i e r F i e l d i s l o c a t e d i n Township 26

North, Range 90 West, Sweetwater County.

The f i e l d was d i s c o v e r e d i n

1916 when a w e l l was completed i n t h e Wall Creek sand and produced 200 b a r r e l s of o i l p e r day.

Tensleep U n i t O i l was d i s c o v e r e d i n t h e Tensleep Sandstone a t L o s t S o l d i e r F i e l d

i n 1930, w i t h t h e completion of a w e l l between 3,942 and 4,009 f e e t

deep.

By J a n u a r y , 1968, 34 o t h e r p r o d u c t i o n w e l l s had been completed

i n t h e same f o r m a t i o n .

The Tensleep r e s e r v o i r i n t h i s a r e a c o v e r s

1 , 4 8 8 a c r e s of f e d e r a l l y and p r i v a t e l y owned l a n d . In order t o maintain reservoir pressure, a water i n j e c t i o n project was i n i t i a t e d i n t h e Tensleep i n 1955.

The w a t e r f l o o d h a s expanded t o

become t h e l a r g e s t of t h e t h r e e i n j e c t i o n p r o j e c t s a t L o s t S o l d i e r F i e l d w i t h 42 w e l l s , 40 of which are c u r r e n t l y (December, 1979) a c t i v e . The Tensleep r e s e r v o i r i n c l u d e s 1 , 1 9 3 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of 250 f e e t .

The primary r e s e r v o i r producing mechanism

i s a combination of w a t e r d r i v e , s o l u t i o n g a s d r i v e , and g r a v i t y drainage.

The Tensleep Sandstone y a s u n i t i z e d i n 1962, under t h e opera-

t i o n of Amoco P r o d u c t i o n Company. Between 1955, when w a t e r i n j e c t i o n began, and December, 1979, 9 167,421,046 b a r r e l s (7.0316 x 1 0 g a l l o n s ) of f r e s h ground w a t e r from t h e B a t t l e S p r i n g , t h e Sundance, Madison, and Tensleep f o r m a t i o n s , and produced F l a t h e a d Sandstone w a t e r were i n j e c t e d i n t o t h e Tensleep a t a v e r a g e i n j e c t i o n p r e s s u r e s between 0 and 2,860 p s i .

Casing Record:

I n j e c t i o n Well #48, T26N-R90W-11 bab, L o s t S o l d i e r F i e l d , Tensleep U n i t , T o t a l Depth = 6572 f e e t .

Casing S i z e

Wt.

13-3/8"

7"

(#/ft) 48 26

Hole S i z e

Depth S e t

17-1/4"

584'

300 s a c k s

6572'

580 s a c k s

9"

Cement

Cambrian U n i t The f i r s t commercial p r o d u c t i o n of o i l from r o c k s of Cambrian a g e i n t h e Rocky Mountain r e g i o n o c c u r r e d i n J u n e , 1948, w i t h t h e completion of a w e l l i n t h e F l a t h e a d Sandstone a t L o s t S o l d i e r F i e l d .

The F l a t h e a d

i s approximately 700 f e e t t h i c k i n t h e Lost S o l d i e r a r e a and is composed p r i m a r i l y of a r k o s i c sandstone.

The p r o d u c t i v e r e s e r v o i r w i t h i n t h e

F l a t h e a d i s a 200-foot t h i c k porous bed near t h e b a s e of t h e formation. The r e s e r v o i r covers 670 a c r e s and has an average pay zone t h i c k n e s s of 94 f e e t .

The i n i t i a l r e s e r v o i r producing mechanism was a l i m i t e d water

d r i v e and f h i d expansion. The Cambrian r e s e r v o i r was u n i t i z e d i n 1962, and two y e a r s l a t e r a water i n j e c t i o n p r e s s u r e maintenance p r o j e c t began. encompasses 938 a c r e s of f e d e r a l and p r i v a t e l a n d .

The u n i t

F i v e d u a l water

i n j e c t i o n w e l l s were a c t i v e i n t h e Cambrian Unit by 1971.

A s of

December, 1979, two of t h e w e l l s had been permanently s h u t - i n and cumulative i n j e c t i o n amounted t o 28,217,966 b a r r e l s (1.1852 x LO

9

g a l l o n s ) of produced water from t h e Sundance, F l a t h e a d , Madison, and Tensleep.

Average i n j e c t i o n p r e s s u r e s f o r t h e p e r i o d ranged from a

vacuum t o 2,875 p s i .

Madison Unit The Madison r e s e r v o i r was u n i t i z e d i n September, 1962, w i t h S i n c l a i r O i l and Gas Corporation a s u n i t o p e r a t o r .

by Amoco Production Company.

The u n i t i s c u r r e n t l y operated

The u n i t p a r t i c i p a t i n g a r e a encompasses

908 a c r e s of f e d e r a l and p r i v a t e l a n d .

The underlying Madison r e s e r v o i r

i n c l u d e s 709 a c r e s w i t h a n average pay zone t h i c k n e s s of 188 f e e t . The Madison Limestone a t Lost S o l d i e r F i e l d i s n e a r l y 300 f e e t t h i c k w i t h t h e b e s t r e s e r v o i r rock o c c u r r i n g n e a r t h e b a s e of t h e formation.

O i l was discovered i n t h e Madison i n January, 1948, i n a

w e l l completed a t a d e p t h between 5,398 and 5,863 f e e t ,

r e s e r v o i r producing mechanism was water d r i v e .

The i n i t i a l

Four d u a l water

i n j e c t i o n w e l l s have been u t i l i z e d f o r p r e s s u r e maintenance s i n c e t h e waterflood p r o j e c t began i n 1965.

By December, 1979, 17,382,630

8 b a r r e l s (7.3007 x 10 g a l l o n s ) of produced water from t h e Sundance, F l a t h e a d , Madison, and Tensleep had been i n j e c t e d t o t h e Madison r e s e r v o i r a t average p r e s s u r e s ranging from a vacuum t o 2,500 p s i .

L-X Bar Ranch F i e l d (790,854 b b l s o i l , 2,864,396 MCF gas; 1973-79) L-X Bar Ranch Unit

The L-X Bar Ranch F i e l d encompasses 2,003 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land i n Townships 55 and 56 North, Range 75 West, Campbell County.

The f i e l d was discovered i n 1973, w i t h a producing w e l l com-

p l e t e d i n t h e Muddy Sandstone.

The Muddy sand i n t h e L-X Bar Ranch

a r e a i s a narrow sand body o r i e n t e d i n a northeast-southwest

direction.

The producing r e s e r v o i r covers 541 a c r e s and has an average t h i c k n e s s of 1 5 . 1 f e e t .

The average p o r o s i t y of t h e producing sands i s 16.5

percent. A secondary recovery waterflood was placed i n o p e r a t i o n i n 1975,

continued f o r t h r e e y e a r s and was subsequently shut-in.

During t h a t

7 g a l l o n s ) of water from t h e

p e r i o d , 1,274,919 b a r r e l s (5.3547 x 10

Muddy and Fox H i l l s sandstones were i n j e c t e d i n t o t h e Muddy r e s e r v o i r . Average i n j e c t i o n p r e s s u r e s over t h e l i f e of t h e p r o j e c t ranged from 1,750 t o 2,450 p s i . Casing Record:

Casing S i z e

I n j e c t i o n Well #8-81, T56N-R75W-35 ccd, L-X Bar Ranch Field-Unit, T o t a l Depth = 8000 f e e t . Wt.

(#/ft)

8-518"

24

5-1/2"

17,15.5

Hole S i z e

Depth S e t

Cement

Purpose

12-1/4"

325 '

235 sacks

Surface

7-7 /8"

8000 '

150 sacks

Injection

Mac F i e l d (90,975 b b l s o i l , 1,572 MCF g a s ; 1970-79) Condon-Federal U n i t I n 1979, a s i n g l e w e l l s a l t w a t e r d i s p o s a l system a t Mac F i e l d began

i n j e c t i n g s a l t w a t e r from Minnelusa Formation producing w e l l s

back i n t o t h e Minnelusa.

Reported TDS c o n c e n t r a t i o n s of produced

Minnelusa w a t e r a t Mac F i e l d a r e approximately 55,500 mg/l.

The

i n j e c t i o n w e l l i s l o c a t e d i n S e c t i o n 28, Township 52 North, Bange 69 West, Campbell County.

Cumulative i n j e c t i o n d a t a were n o t y e t a v a i l -

a b l e a t t h e t i m e t h i s r e p o r t was w r i t t e n .

Casing Record:

S a l t Water D i s p o s a l W e l l #2, T52N-R69W-28 c c , Mac F i e l d , Condon-Federal U n i t , T o t a l Depth = 7816 f e e t .

Casing S i z e

Wt.

8-518" 5-112"

(#/ft) 24

15.5,17

Hole S i z e

Depth S e t

12-114"

225 '

7-718''

7816 '

Cement Circulated 60 s a c k s

Madden F i e l d (222,777 b b l s o i l , 125,437,516 MCF g a s ; 1969-79) Madden Deep U n i t Monsanto Company began o p e r a t i n g a s i n g l e w e l l s a l t w a t e r d i s p o s a l system a t Madden F i e l d i n 1979.

The w e l l i s l o c a t e d i n S e c t i o n 31,

Township 39 North, Bange 90 West, Fremont County, and i s p e r f o r a t e d a t a d e p t h of 5,922 f e e t i n t h e lower p a r t of t h e F o r t Union Formation. I n j e c t i o n d a t a were n o t y e t a v a i l a b l e f o r t h e p r o j e c t as of December, 1979. Casing Record: Casing S i z e

S a l t Water D i s p o s a l Well #1-12, T39N-R90W-31 b c , Madden F i e l d , Madden Deep U n i t , T o t a l Depth = 11,422 f e e t . Wt.

(#/ft)

Depth S e t

5-112"

20

2113'

5-1/2"

17

7332'

5-112"

17

11422 '

Cement 1740 s a c k s

E a s t Mahoney F i e l d (10,757,623 MCF g a s ; 1923-79) Dakota U n i t Very l i t t l e i n f o r m a t i o n on t h e n a t u r a l g a s s t o r a g e p r o j e c t a t t h e Dakota U n i t of E a s t Mahoney F i e l d i s a v a i l a b l e from O i l and Gas Commission f i l e s .

Gas i s r e p o r t e d l y s t o r e d i n t h e Dakota, Sundance, and

Muddy s a n d s a t u n r e p o r t e d d e p t h s .

E a s t Mahoney Dome F i e l d i s l o c a t e d

i n Township 26 North, Ranges 87 and 88 West, Carbon County. Manning F i e l d (1,172,470 b b l s o i l , 1,895,280 MCF gas; 1970-79) # 1 F e d e r a l 44-17 U n i t I n a d d i t i o n t o t h e 23 producing w e l l s a t Manning o i l and g a s f i e l d , t h e r e i s a s i n g l e w e l l s a l t w a t e r d i s p o s a l system which i s completed i n t h e Parkman sand a t a d e p t h of 8,416 f e e t .

The system began o p e r a t i n g

i n 1978, and by J u n e , 1980, 343,739 b a r r e l s (14,437,038 g a l l o n s ) of produced b r i n e had been

i n j e c t e d t o t h e Parkman.

The a v e r a g e

i n j e c t i o n p r e s s u r e h a s ranged from 0 t o 1,500 p s i d u r i n g t h a t time. Casing Record:

Casing S i z e

S a l t Water D i s p o s a l W e l l ill, T39N-R73W-17, Manning F i e l d , # 1 F e d e r a l 44-17 U n i t , T o t a l Depth = 8577 f e e t . Wt.

(#/ft)

Depth S e t

Cement

8-5 18"

24

1022 '

525 s a c k s

5-1/2"

17

8577'

250 s a c k s

Maverick S p r i n g s F i e l d (10,987,067 b b l s o i l ; 1917-79) Chatterton Unit Maverick S p r i n g s F i e l d i s l o c a t e d i n Township 6 North, Range 2 West, Fremont County.

A s a l t water d i s p o s a l w e l l , l o c a t e d i n S e c t i o n 1 5 of

t h e same township and r a n g e , was a c t i v a t e d i n 1971, t o i n j e c t produced b r i n e s i n t o t h e Embar Formation.

A s of December, 1979, 3,912,413

8 b a r r e l s (1.6432 x 1 0 g a l l o n s ) of b r i n e had been i n j e c t e d .

McDonald Draw F i e l d (7,468,812 b b l s o i l ; 32,842,380 MCF g a s ; 1960-79) The Almy sand, u s u a l l y c o n s i d e r e d a s t h e b a s a l member of t h e Wasatch Formation, i s t h e p r i n c i p a l producing zone of McDonald Draw Field.

More t h a n 20 producing s a n d s have been found i n t h e Almy member

w i t h i n t h e 18,742 a c r e a r e a of t h e McDonald Draw p a r t i c i p a t i n g a r e a . The f i e l d was d i s c o v e r e d i n 1960, w i t h t h e completion of a g a s producing w e l l i n t h e Wasatch Formation between 3,000 and 3,035 f e e t .

The i n i t i a l

o i l producing w e l l s i n b o t h t h e "south o i l pool" and t h e " n o r t h o i l pool" were completed i n 1961. I n t h e " s o u t h pool" a r e a , w a t e r f l o o d p r o j e c t s i n t h e M-9 and M-13 s a n d s began i n October, 1964,

By J a n u a r y , 1966, t h r e e more s a n d s of

t h e Almy member, t h e M-20, M-42,

and M-47 s a n d s , were i n c l u d e d i n t h e

fieldwide water i n j e c t i o n project,

Almy M-9 U n i t The Almy M-9 r e s e r v o i r i s found a t d e p t h s between 3,058 and 3,204 f e e t i n t h e McDonald Draw a r e a .

The r e s e r v o i r c o v e r s 200 a c r e s and h a s

a n a v e r a g e pay zone t h i c k n e s s of 1 2 f e e t .

P o r o s i t y and p e r m e a b i l i t y

a v e r a g e 22 p e r c e n t and 34 m i l l i d a r c i e s , r e s p e c t i v e l y ,

Cumulative

i n j e c t i o n through f i v e d u a l i n j e c t i o n w e l l s was 4,116,849 b a r r e l s 8 (1.7501 x 1 0 g a l l o n s ) as of December, 1979. by producing w e l l s i n t h e Almy s a n d s . a c t i v e l y i nje c t i n g

Injection water is supplied

Two of t h e f i v e w e l l s were s t i l l

.

Almy M-13 U n i t The Almy M-13 sand l i e s s t r a t i g r a p h i c a l l y above t h e M-9 sand i n t h e McDonald D r a w a r e a and i n c l u d e s 350 a c r e s of r e s e r v o i r r o c k w i t h a n a v e r a g e pay zone t h i c k n e s s of 1 0 f e e t .

Isopach c o n t o u r s based on w e l l

l o g s i n d i c a t e t h a t t h e M-13 U n i t r e s e r v o i r i s a c t u a l l y a p a i r of i n t e r connected l e n s e s .

S i x i n j e c t i o n w e l l s have o p e r a t e d i n t h e M-13 U n i t

o v e r t h e l i f e t i m e of t h e p r o j e c t .

F i v e of t h o s e w e l l s a r e d u a l i n j e c t o r s

i n t h e M-9 and M-13 s a n d s .

However, o n l y one of t h e w e l l s , a d u a l

injector, is still active.

A s of December, 1979, 4,292,331 b a r r e l s

8 (1.8028 x 1 0 g a l l o n s ) of produced w a t e r had been i n j e c t e d t o t h e M-13 sand a t a v e r a g e p r e s s u r e s between 1,410 and 2,600 p s i . Almy M-17 U n i t The Almy 14-17 U n i t i s t h e s i t e of t h e s o l e s a l t w a t e r d i s p o s a l w e l l of McDonald Draw F i e l d . #17 (T28N-R112W-29

I n j e c t i o n of produced b r i n e t h r o u g h w e l l

d c ) s t a r t e d i n 1968.

Through J a n u a r y , 1971, 280,514

7 b a r r e l s (1.1781 x 1 0 g a l l o n s ) of w a t e r had been d i s p o s e d of i n a twof o o t t h i c k l e n s e of Almy sand a t a d e p t h of 3,103 f e e t .

Average

i n j e c t i o n p r e s s u r e s have ranged from 1,000 t o 2,000 p s i .

Casing Record:

Casing S i z e 4-1/2"

D i s p o s a l W e l l #17, T28N-R112W-29 d c , McDonald Draw F i e l d , Almy M-17 U n i t , T o t a l Depth = 3240 f e e t . Wt.

(#/ft)

9.5,10.5,11.6

Depth S e t 3240'

Cement 175 s a c k s

Almy M-20 U n i t Water i n j e c t i o n t o t h e Almy M-20 U n i t of McDonald Draw F i e l d s t a r t e d i n December, 1965, through t h r e e w e l l s t h a t a r e d u a l l y p e r f o r a t e d i n t h e M-20 and M-47 s a n d s .

The p r o j e c t was l a t e r expanded t o i n c l u d e

e i g h t w e l l s , s i x of which are d u a l i n j e c t o r s . The Almy M-20 r e s e r v o i r encompasses 480 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of 1 6 f e e t .

P o r o s i t y and p e r m e a b i l i t y w i t h i n t h e reser-

v o i r sand a v e r a g e 1 8 p e r c e n t and 52 m i l l i d a r c i e s , r e s p e c t i v e l y .

Between

December, 1965, and December, 1979, 8,674,203 b a r r e l s (3.6432 x 108 g a l l o n s ) of Almy sand water were i n j e c t e d .

Average i n j e c t i o n

p r e s s u r e s were 1,320 t o 2,550 p s i .

Almy M-42 Unit The Almy M-42 sand r e s e r v o i r covers an a r e a of 260 a c r e s w i t h an average pay zone t h i c k n e s s of 10 f e e t .

The productive boundaries of

t h e r e s e r v o i r a r e c o n t r o l l e d by permeable sand pinchouts on t h e n o r t h , s o u t h , and w e s t , and by an oil-water c o n t a c t t o t h e e a s t .

The primary

d r i v e mechanism of t h e r e s e r v o i r i s s o l u t i o n gas expansion. Water i n j e c t i o n began i n January, 1966, through two w e l l s . t h i r d w e l l was added i n 1969.

A

Cumulative i n j e c t i o n t o December, 1979,

7 was 1,922,647 b a r r e l s (8.0751 x 10 g a l l o n s ) of f r e s h and produced Almy sand water.

I n j e c t i o n p r e s s u r e s averaged 1,375 t o 2,400 p s i over

t h e 1 3 year period.

Only one of t h e w e l l s (1142) i s s t i l l on a c t i v e

injection status.

Almy M-47 Unit The Almy M-47 r e s e r v o i r has t h e l a r g e s t sand volume of t h e s i x Almy sand u n i t s a t McDonald Draw F i e l d w i t h water i n j e c t i o n p r o j e c t s . The r e s e r v o i r spans 480 a c r e s w i t h an average t h i c k n e s s of 30 f e e t . I n j e c t i o n of f r e s h and produced Almy water began i n December, 1965, through t h r e e w e l l s d u a l l y p e r f o r a t e d i n both t h e M-20 and M-47 sands.

Water i s i n j e c t e d t o t h e deeper M-20 sand through t h e tubing

while i n j e c t i o n t o t h e M-47 sand i s through annular p e r f o r a t i o n s .

Two

more d u a l i n j e c t o r s were added i n 1969 and 1973, and a t h i r d w e l l , p e r f o r a t e d only i n t h e M-47 sand, was completed i n 1972.

F i v e of t h e

s i x w e l l s were a c t i v e l y i n j e c t i n g through December, 1979, when t h e

c u m u l a t i v e i n j e c t e d volume of w a t e r was 9,182,599 b a r r e l s (3.8567 x 8 10 gallons).

Average i n j e c t i o n p r e s s u r e s have v a r i e d between a minimum

of 600 p s i and a maximum of 2,600 p s i . Almy M-50 U n i t The Almy M-50 U n i t i s l o c a t e d i n Townships 28 and 29 North, Range 112 West, S u b l e t t e County.

Water i n j e c t i o n t o t h e M-50 sand began i n

1972, through t h r e e d u a l i n j e c t i o n w e l l s .

Cumulative i n j e c t i o n between

7 1972 and December, 1979, t o t a l e d 847,654 b a r r e l s (3.5601 x 1 0 g a l l o n s ) of f r e s h and produced w a t e r from t h e Almy sand a t i n j e c t i o n p r e s s u r e s t h a t averaged between 1 , 6 6 5 and 2,600 p s i . added t o t h e p r o j e c t i n 1974.

One i n j e c t i o n w e l l was

Two of t h e f o u r w e l l s have been s h u t - i n

since then.

M-D F i e l d (4,065,720 b b l s o i l ; 1967-79)

T. P. L e C l a i r U n i t The T. P. L e C l a i r U n i t of M-D F i e l d i s l o c a t e d i n Township 53 North, Range 69 West, Campbell County, and h a s been t h e s i t e of a s i n g l e w e l l s a l t w a t e r d i s p o s a l system s i n c e 1968.

The i n j e c t i o n w e l l i s completed

i n t h e lower Minnelusa Formation a t a d e p t h of 7,236 f e e t .

Between t h e

time of t h e i n i t i a l i n j e c t i o n s and December, 1979, 637,827 b a r r e l s 7 (2.6788 x 1 0 g a l l o n s ) of produced b r i n e were

i n j e c t e d t o t h e lower

Minnelusa a t a v e r a g e i n j e c t i o n p r e s s u r e s between 638 and 8 5 1 p s i .

Casing Record:

S a l t Water D i s p o s a l Well #1, T53N-R69W-36 dd, M-D F i e l d , T. P. L e C l a i r U n i t , T o t a l Depth = 7357 f e e t .

Casing S i z e 5-1/2"

Wt.

(#/ft)

15.5,17

Depth S e t 7357'

Cement 250 s a c k s

Government

-

C. F. True Unit

A second s a l t water d i s p o s a l w e l l was p u t i n t o o p e r a t i o n a t M-D

This w e l l i s l o c a t e d i n S e c t i o n 1, Township 52 North,

F i e l d i n 1970.

Range 69 West, Campbell County, and completed i n t h e Dakota and Lakota sands a t a depth of 5,808 f e e t .

A s of December, 1979, 3,325,970

8 b a r r e l s (1.3969 x 10 g a l l o n s ) of produced b r i n e had been

injected

s i n c e t h e p r o j e c t began.

Casing Record:

S a l t Water Disposal Well #GT-1, T52N-R69W-1 a b , M-D F i e l d , Government - C. I?. True U n i t , T o t a l Depth = 7427 f e e t .

Casing S i z e

wt.

10-3/4"

( m t )

Hole S i z e

40.5

5-1/2"

15"

15.5,17,20

8-3/4"

Depth S e t

Cement

413'

260 sacks

7437 '

235 sacks

Meadow Creek F i e l d (31,028,960 b b l s o i l , 77,819,790 MCF gas; 1950-79) The Meadow Creek o i l f i e l d i s l o c a t e d about 65 m i l e s n o r t h of Casper, Wyoming, i n Township 41 North, Range 78 West, and one s e c t i o n of Township 42 North, Range 78 West, Johnson County.

O i l was f i r s t

discovered i n t h e Meadow Creek a r e a on A p r i l 3, 1950, i n t h e Lakota Sandstone a t a depth of 7,475 f e e t .

Subsequent producing w e l l s were

completed i n t h e second F r o n t i e r , Tensleep, Shannon, and Sussex sands. A n a t u r a l g a s processing p l a n t was c o n s t r u c t e d a t Meadow Creek F i e l d

i n 1953, t o process l o c a l l y derived g a s , remove butane and propane, and r e - i n j e c t

t h e gas i n t o t h e Sussex, Shannon, Lakota, and Tensleep

producing zones. C o n t i n e n t a l O i l Company has operated t h e water i n j e c t i o n p r o j e c t s i n t h e Shannon "A"

and "B,"

and Tensleep "A" U n i t s . Lakota "B"

Second F r o n t i e r , Lakota "A,"

Lakota "B,"

The f i r s t such p r o j e c t was undertaken i n t h e

r e s e r v o i r i n 1956.

Water supply f o r t h e Meadow Creek a r e a i n j e c t i o n w e l l s i s obtained from t h e Shiloh Water Supply System which c o n s i s t s of f o u r w e l l s The system i s a l s o operated by

completed i n t h e Madison Limestone. t h e C o n t i n e n t a l O i l Company.

Lakota "B" Unit The Lakota "B"

r e s e r v o i r i s a l i g h t brownish-gray,

c h e r t y , coarse-

grained t o conglomeratic, q u a r t z o s e sandstone of t h e Lower Cretaceous. The a r e a l e x t e n t of t h e r e s e r v o i r i s 350 a c r e s w i t h an average t h i c k n e s s of 60 f e e t and an average pay t h i c k n e s s of 20 f e e t .

P o r o s i t y averages

about 1 5 p e r c e n t and t h e p e r m e a b i l i t y v a r i e s between 40 and 200 millidarcies. The p r o d u c t i v e boundaries of t h e Lakota "B" Unit a r e d e f i n e d by a normal north-dipping f a u l t on t h e n o r t h s i d e and by t h e oil-water c o n t a c t on t h e s o u t h , e a s t , and west. Water i n j e c t i o n i n t o t h e Lakota "B" was terminated i n 1964.

r e s e r v o i r began i n 1956, and

During t h a t p e r i o d , 651,330 b a r r e l s of water

(27,355,860 g a l l o n s ) were i n j e c t e d i n t o t h e formation.

Since 1964, two

of t h e i n j e c t i o n w e l l s have been recompleted a s o i l production w e l l s i n t h e Shannon "A-B"

Casing Record: Casing S i z e 10-3/4"

Unit.

I n j e c t i o n Well #60, T41N-R78W-10 c c a , Meadow Creek F i e l d , Lakota "B" U n i t , T o t a l Depth = 7445 f e e t . Wt.

(#/ft)

Make

29

Spiral

23

5-55, N-80

Depth S e t

Cement

Purpose

175 '

175 sacks

Surface

7445'

250 sacks

Injection

Second F r o n t i e r "A1' Unit The second F r o n t i e r sand i s t h e middle u n i t of t h r e e " s a l t and pepper1' sandstone beds w i t h i n t h e F r o n t i e r Formation.

The F r o n t i e r

sands a r e L a t e Cretaceous i n age and a r e p a r t of a f a u l t e d a n t i c l i n a l structure.

Production i n t h e second F r o n t i e r sand i s bounded on t h e

n o r t h by a s e a l i n g normal f a u l t , on t h e west and south by an oil-water c o n t a c t and on t h e e a s t by a f a c i e s change from sand t o s h a l e y sand which s i g n i f i c a n t l y d e c r e a s e s p e r m e a b i l i t y . The Second F r o n t i e r "A"

r e s e r v o i r a r e a l l y covers 964 a c r e s and i s

found a t an average depth of 6,556 f e e t .

It has an average t h i c k n e s s

of 90 f e e t w i t h an average o i l productive t h i c k n e s s of 12 t o 20 f e e t The estimated p o r o s i t y of t h e

and a s t r u c t u r a l c l o s u r e of 60 f e e t . r e s e r v o i r i s about 15 p e r c e n t .

O i l production from t h e Second F r o n t i e r "A1' Unit was i n i t i a t e d i n

1951, by t h e C o n t i n e n t a l O i l Company. through w e l l #89.

Water i n j e c t i o n began i n 1963,

Two a d d i t i o n a l i n j e c t i n g w e l l s were completed i n

1968, one more was added i n 1970, and another i n 1978.

A s of J u l y ,

1979, t h e r e were f i v e w e l l s a c t i v e l y i n j e c t i n g water i n t o t h e second F r o n t i e r sand.

Fresh water f o r i n j e c t i o n i s drawn from t h e Madison

Limestone (Shiloh Water Supply L i n e ) .

The cumulative volume of water

i n j e c t e d s i n c e t h e p r o j e c t began i s 8,345,154 b a r r e l s (3.5049 x 8 10 g a l l o n s ) .

Casing Record: Casing S i z e 10-3/4" 7"

I n j e c t i o n Well #28, T4lN-R78W-10 daa, Meadow Creek F i e l d , Second F r o n t i e r "A" U n i t , T o t a l Depth = 7554 f e e t . Wt.

Depth S e t

Cement

Purpose

(#/ft)

Make

36

H-40

166 '

150 sacks

Surface

23

5-55

7554'

550 sacks

Injection

Tensleep "A" Unit The Tensleep Sandstone i s a Pennsylvanian-Permian age sandstone found a t an average depth of 9,000 f e e t i n t h e Meadow Creek a r e a . Tensleep i s composed of c l e a n , w h i t e , f i n e - t o medium-grained,

The

friable

sand w i t h some s t r e a k s of hard, d o l o m i t i c sand. S t r u c t u r a l l y , t h e u n i t is p a r t of an a n t i c l i n e and i s bounded on a l l s i d e s by an oil-water c o n t a c t .

The g r o s s t h i c k n e s s of t h e sand-

s t o n e i s 200-250 f e e t w i t h an average pay t h i c k n e s s of 17 f e e t and a maximum c l o s u r e of 60 f e e t .

Reservoir d a t a c o l l e c t e d by t h e C o n t i n e n t a l

O i l Company i n d i c a t e an average p o r o s i t y of 11 p e r c e n t and p e r m e a b i l i t y

of 14 m i l l i d a r c i e s . The a r e a l e x t e n t of t h e Tensleep "A" r e s e r v o i r i s 2,918 a c r e s , b u t t h e u n i t p a r t i c i p a t i n g i s only 1,560 a c r e s , 1,440 of which a r e f e d e r a l l y owned w i t h 120 a c r e s of p r i v a t e l y owned f e e lands. Primary o i l production began i n 1953, and was predominantly cont r o l l e d by an a c t i v e n a t u r a l water d r i v e from t h e west and n o r t h .

The

i n j e c t i o n of f l u i d s was i n i t i a t e d i n 1963, w i t h t h e i n j e c t i o n of n a t u r a l gas and water i n t o t h e r e s e r v o i r .

C u r r e n t l y ( J u l y , 1979), t h e r e a r e

f o u r a c t i v e w a t e r i n j e c t i o n w e l l s , two temporarily s h u t - i n w e l l s and a water supply w e l l , which i s completed i n t h e Madison Limestone.

The

water supply w e l l provided 9,000 b a r r e l s (378,000 g a l l o n s ) of w a t e r d u r i n g an 8-hour w e l l t e s t f o r an e s t i m a t e d flowing p o t e n t i a l of 87,000 b a r r e l s of water (3,654,000 g a l l o n s ) per day.

Cumulative w a t e r i n j e c t i o n

i n t o t h e Tensleep "A" r e s e r v o i r has t o t a l e d 21,400,468 b a r r e l s (8.988 8 x 1 0 g a l l o n s ) ( J u l y , 1979).

It i s e s t i m a t e d t h a t 3,130,000 b a r r e l s

of o i l w i l l b e obtained a s a r e s u l t of secondary recovery by f l u i d injection.

Casing Record:

I n j e c t i o n Well #178, T41N-R78W-1 dbd, Meadow Creek F i e l d , Tensleep "A" U n i t , T o t a l Depth = 9088 f e e t .

Casing S i z e

Wt.

19-3/4" 7"

(#/ft)

Depth S e t

Hole S i z e

32.75

340 '

13-3/4"

23,26

9088 '

Cement 200 sacks

9"

650 sacks

Shannon "A" Unit The Shannon Sandstone i s an Upper Cretaceous gray o r green, f i n e t o medium-grained,

g l a u c o n i t i c sandstone which occurs a t an average

depth of 4,200 f e e t i n t h e Meadow Creek F i e l d . c o n s i s t s of two sand benches--the

The Shannon sand

main Shannon and t h e f a l s e Shannon.

The f a l s e Shannon i s developed on t h e northwest and west s i d e s of t h e r e s e r v o i r and has a g r o s s t h i c k n e s s of 18 f e e t .

The main Shannon

u n d e r l i e s t h e f a l s e Shannon and 30 t o 50 f e e t of s h a l e .

It h a s a g r o s s

t h i c k n e s s of 40 f e e t and a maximum s t r u c t u r a l c l o s u r e of 350 f e e t . The average p o r o s i t y of t h e Shannon sands i s 25 p e r c e n t . The Shannon sands a r e p a r t of a normally f a u l t e d a n t i c l i n e which

i s d i v i d e d i n t o f o u r d i s t i n c t f a u l t blocks w i t h l i m i t e d communication between t h e blocks a s a r e s u l t of an average f a u l t displacement of 100 feet.

The e n t i r e s t r u c t u r e i s bounded by more f a u l t i n g t o t h e n o r t h ,

f a u l t i n g and sand development t o t h e e a s t and s o u t h , and an oil-water contact t o the w e s t .

The a r e a l e x t e n t of t h e Shannon "A-B"

reservoir

is 3,759 a c r e s w i t h an average pay t h i c k n e s s of 16 f e e t . The C o n t i n e n t a l O i l Company began producing o i l from t h e Shannon Sandstone i n 1950.

To enhance o i l production, gas i n j e c t i o n (gas and

l i q u e f i e d petroleum gas) was i n i t i a t e d i n March, 1953.

A p i l o t program

f o r w a t e r f l o o d i n g s t a r t e d i n 1960, and has developed i n t o t h e l a r g e s t water i n j e c t i o n p r o j e c t a t Meadow Creek F i e l d .

Since 1960, more than

27,570,426 b a r r e l s of water (1.1579 x 109 g a l l o n s ) have been i n j e c t e d i n t o t h e Shannon "A-B"

Unit through 25 i n j e c t i o n w e l l s .

A s of August,

1979, 17 of t h e w e l l s were s t i l l a c t i v e i n j e c t o r s , while 8 had been temporarily shut-in.

The s o u r c e of i n j e c t e d water i s t h e Madison

Limestone (Shiloh Water Supply Line).

Casing Record:

I n j e c t i o n Well #lo, T41N-R78W-2 bbb, Meadow Creek F i e l d , Shannon "A" U n i t , T o t a l Depth = 4415 f e e t .

Casing S i z e

Wt.

(///ft)

Make

Depth S e t

Cement

9-5 /8"

40

5-55

222'

200 sacks

7"

20

H-40

4415 '

175 sacks

Lakota "A" Unit The Lower Cretaceous Lakota Sandstone of t h e Lakota "A" p a r t i c i p a t i n g a r e a c o n s i s t s of two porous sand zones s e p a r a t e d by a s h a l e bed.

The

a r e a l e x t e n t of t h e Lakota "A" r e s e r v o i r i s 1,230 a c r e s w i t h an average pay t h i c k n e s s of 15 f e e t .

The t o t a l u n i t a r e a i s 710 acres--650

acres

a r e f e d e r a l l y owned and t h e remainder a r e p r i v a t e l y owned f e e l a n d s . The p r o d u c t i v e boundaries of t h e c h e r t y , coarse-grained t o conglomeratic q u a r t z o s e sandstone a r e defined by a major f a u l t t o t h e n o r t h , an oil-water c o n t a c t t o t h e s o u t h and west, and a f a c i e s change from a porous, permeable sand t o a t i g h t , s h a l e y sandstone on t h e e a s t e r n edge. Average p o r o s i t y w i t h i n t h e Lakota "A" Unit i s 15 p e r c e n t w i t h a v a r i a b l e p e r m e a b i l i t y which ranges between 40 and 200 m i l l i d a r c i e s . Gas i n j e c t i o n i n t o t h e r e s e r v o i r began i n 1953, and was continued u n t i l 1980.

During t h a t time 12.8 b i l l i o n c u b i c f e e t were i n j e c t e d .

I n 1963, a f u l l s c a l e water i n j e c t i o n o p e r a t i o n was s t a r t e d around t h e

p e r i m e t e r of t h e r e s e r v o i r .

Between 1963 and August, 1979, 6,857,587

8 b a r r e l s of w a t e r (2.88 x 1 0 g a l l o n s ) were i n j e c t e d i n t o t h e Lakota "Af' U n i t .

Casing r e c o r d s were n o t a v a i l a b l e f o r t h e i n j e c t i o n w e l l s

i n this unit.

North Meadow Creek F i e l d (9,485,328 b b l s o i l , 28,598,359 MCF g a s ; 1949-79) The North Meadow Creek F i e l d i s l o c a t e d on t h e west f l a n k of t h e Powder R i v e r Basin between Meadow Creek and Sussex f i e l d s , on a f a u l t e d a n t i c l i n a l n o s e p h n g i n g n o r t h from t h e Meadow Creek s t r u c t u r e .

Several

t r a n s v e r s e normal f a u l t s c u t t h i s n o s e forming o i l and g a s t r a p s i n t h e Sussex and Shannon s a n d s t o n e s , and t h e F r o n t i e r Formation. The North Meadow Creek F i e l d p r o d u c t i o n and i n j e c t i o n p r o j e c t s a r e o p e r a t e d by t h e C o n t i n e n t a l O i l Company.

A s of August, 1979, a l l of

t h e 47 i n j e c t i o n w e l l s of t h e North Meadow Creek F i e l d were t e m p o r a r i l y shut-in. Sussex U n i t The Upper C r e t a c e o u s Sussex Sandstone i s a l i g h t - g r a y t o g r e e n , f i n e - t o medium-grained,

highly g l a u c o n i t i c sand, very s i m i l a r t o t h e

Shannon sand and j u s t above t h e Shannon s t r a t i g r a p h i c a l l y .

The Sussex

Sandstone i s found a t a n approximate d e p t h of 3,900 f e e t i n t h e North Meadow Creek a r e a and c o v e r s 962 a c r e s w i t h a n a v e r a g e pay t h i c k n e s s of 32 f e e t .

The t o t a l p a r t i c i p a t i n g a r e a of t h e Sussex U n i t i s 1 , 5 6 0

a c r e s , of which 1 , 2 4 0 a c r e s a r e f e d e r a l l y owned and 320 a c r e s are s t a t e owned. S t r u c t u r a l l y , t h e Sussex U n i t i s p a r t of a n a n t i c l i n e which i s t r u n c a t e d on t h e s o u t h by a major east-west t r e n d i n g f a u l t w i t h a maximum d i s p l a c e m e n t of 230 f e e t .

The f a u l t d e l i n e a t e s t h e p r o d u c t i v e

boundary of t h e Sussex sand on t h e south.

Production i s l i m i t e d i n

o t h e r d i r e c t i o n s by an oil-water c o n t a c t and by minor f a u l t i n g .

Faulting

d i v i d e s t h e r e s e r v o i r i n t o t h r e e d i s t i n c t blocks w i t h l i t t l e h y d r a u l i c communication between them.

The maximum s t r u c t u r a l c l o s u r e on t h e

Sussex r e s e r v o i r i s 150 f e e t . O i l production s t a r t e d i n 1951, and was c o n t r o l l e d predominantly by

s o l u t i o n gas d r i v e .

The waterflooding o p e r a t i o n s began i n 1953, using

an i r r e g u l a r f i v e - s p o t p a t t e r n t o enhance production.

It was estimated

t h a t secondary f l o o d i n g would provide an a d d i t i o n a l 830,000 b a r r e l s of o i l from t h e Sussex r e s e r v o i r . A l l of t h e i n j e c t i o n w e l l s have been s h u t - i n i n t h e Sussex Unit s i n c e 1971.

Cumulative i n j e c t i o n from t h e 27 w e l l s has been roughly

8 20 m i l l i o n b a r r e l s of water (8.4 x 10 g a l l o n s ) .

S e v e r a l of t h e w e l l s

have been recompleted s i n c e 1968, from t h e Sussex t o t h e Shannon sand f o r t h e purpose of producing o i l from t h e Shannon r e s e r v o i r .

Casing Record:

I n j e c t i o n Well #12, T42N-R78W-36 abd, North Meadow Creek F i e l d , Sussex U n i t , T o t a l Depth = 4436 f e e t .

Casing S i z e 10-3/4" 7"

Wt.

(#/ft) 32.75 20

Depth S e t

Cement

239 '

200 sacks

4436'

300 sacks

Shannon Unit The Shannon sand r e s e r v o i r i s found a t an average depth of 4,430 f e e t w i t h i n t h e a r e a of North Meadow Creek F i e l d .

The a r e a l e x t e n t of

t h e Upper Cretaceous sand i s 1,214 a c r e s w i t h a n e t productive sand t h i c k n e s s which ranges between 0 and 18 f e e t and averages 12 f e e t . t o t a l p a r t i c i p a t i n g a r e a of t h e Shannon Unit i s 1,597.5 a c r e s .

The

Federally

owned land comprises 1,280 a c r e s and s t a t e l a n d s comprise 317.5 a c r e s .

A major f a u l t t o t h e south and t h e oil-water c o n t a c t on t h e o t h e r

s i d e s o u t l i n e t h e p r o d u c t i v e a r e a of t h e Shannon sand.

The primary

mechanism f o r o i l production was s o l u t i o n gas d r i v e when t h e North Meadow Creek Shannon Unit was developed i n 1950. Secondary recovery of o i l by waterflooding was i n i t i a t e d i n 1959, w i t h a f i v e - s p o t and p e r i p h e r a l flood p a t t e r n .

I n 1977, t h e waterflood

p a t t e r n was considered t o be i n e f f e c t i v e and was discontinued.

The

r a t i o of produced o i l t o produced water had r i s e n t o 9 . 6 : l i n 1976 and 10.0:l i n 1977 compared t o a 0 , 9 : 1 cumulative r a t i o s i n c e t h e waterf l o o d i n g program began.

Hydraulic communication between t h e Shannon

and Sussex sands was considered a major c o n t r i b u t i n g f a c t o r . A t t h e p r e s e n t time, a l l producing w e l l s i n t h e Shannon r e s e r v o i r

have been shut-in temporarily.

Four of t h e w e l l s a r e equipped t o r e t u r n

t o producing s t a t u s a s soon a s a renewed water i n j e c t i o n program a f f e c t s t h e a r e a s n e a r t h e production w e l l s .

I n j e c t i o n water has been supplied

by t h r e e North Meadow Creek w e l l s completed i n t h e Madison Limestone. Casing Record:

I n j e c t i o n Well 866, T42N-R78W-36 abd, North Meadow Creek F i e l d , Shannon U n i t , T o t a l Depth = 4437 f e e t .

Casing S i z e

Wt.

10-3/4" 7"

(#/ft)

Depth S e t

Cement

32.75

262 '

170 sacks

23

4437 '

300 sacks

F r o n t i e r Unit The North Meadow Creek F r o n t i e r Formation i s a t i g h t , f i n e - t o medium-grained,

" s a l t and pepper" sandstone w i t h s t r e a k s of s h a l e .

The

formation ranges i n t h i c k n e s s from 26 t o 63 f e e t and occurs a t an average depth of 6,500 f e e t .

The sandstone i s e x t e n s i v e l y f r a c t u r e d both

v e r t i c a l l y and h o r i z o n t a l l y .

Average v a l u e s of t h e p o r o s i t y and

p e r m e a b i l i t y of t h e Upper Cretaceous sand a r e 11.9 p e r c e n t and 0.5 millidarcies, respectively. The F r o n t i e r r e s e r v o i r is productive over an a r e a of 3,850 a c r e s . It i s s i t u a t e d w i t h i n t h e broad Meadow Creek a n t i c l i n e and i s a combined

s t r u c t u r a l and s t r a t i g r a p h i c t r a p .

The productive u n i t of t h e F r o n t i e r

i s bounded on t h e e a s t by an e x t e n s i v e oil-water t r a n s i t i o n zone, on

t h e w e s t by a d e c r e a s e i n r e s e r v o i r p e r m e a b i l i t y , on t h e n o r t h by a s e a l i n g f a u l t , and on t h e s o u t h by decreased p e r m e a b i l i t y and t h e o i l water c o n t a c t . The F r o n t i e r Unit a r e a covers 3,953.52 a c r e s .

The a r e a i s divided

between f e d e r a l l y owned (2,133.94 a c r e s ) , s t a t e owned (640 a c r e s ) , and p r i v a t e l y owned f e e l a n d s (1,179,58 a c r e s ) . The w a t e r - o i l r a t i o f o r producing w e l l s completed i n t h e F r o n t i e r r e s e r v o i r was 2.5:l i n 1918,compared t o a cumulative r a t i o of .l:l s i n c e production began. The F r o n t i e r r e s e r v o i r has a l s o been used a s a s a l t water d i s p o s a l s i t e s i n c e 1974.

Water produced w i t h o i l from F r o n t i e r w e l l s i s

r e - i n j e c t e d a t a depth of 6,573 f e e t through w e l l /,I6 (T42N-R78W-25 d a ) . I n 1967, a n a t u r a l gas i n j e c t i o n p r o j e c t began a t t h e North Meadow Creek F r o n t i e r Unit.

Through 1979, 2,784,080 m i l l i o n cubic f e e t (MCF)

of gas had been i n j e c t e d i n t o t h e F r o n t i e r Formation through two w e l l s p e r f o r a t e d a t depths of 6,258 and 6,278 f e e t . actively injecting.

One of t h e w e l l s i s s t i l l

Average i n j e c t i o n p r e s s u r e s have ranged from 0

t o 1,800 p s i . Information on i n d i v i d u a l producing, water d i s p o s a l , and water and gas i n j e c t i o n w e l l s was u n a v a i l a b l e a t t h e time t h i s r e p o r t was w r i t t e n .

M e l l o t t Ranch F i e l d (4,047,023 b b l s o i l ; 1960-79) Minnelusa Unit M e l l o t t Ranch F i e l d covers 1,000 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land i n w e s t - c e n t r a l Crook County.

The Minnelusa Formation

o i l discovery w e l l was completed i n 1961, a t depths between 6,782 and 6,804 f e e t .

The Minnelusa r e s e r v o i r spans approximately 700 a c r e s w i t h

an average pay zone t h i c k n e s s of 25 f e e t .

Core a n a l y s e s i n d i c a t e an

average r e s e r v o i r p o r o s i t y of 16 p e r c e n t .

The primary producing energy

i s provided by f l u i d expansion. Water i n j e c t i o n f o r secondary recovery of o i l was approved i n June, 1965, w i t h S h e l l O i l Company a s o p e r a t o r .

However, t h e i n i t i a l

i n j e c t i o n d i d n o t occur u n t i l December of t h a t y e a r .

Water supply f o r

t h e p r o j e c t is from t h e w e l l s completed i n t h e Fox H i l l s Sandstone a t a depth of about 1,000 f e e t . injection wells.

O r i g i n a l l y , t h e p r o j e c t had two

A t h i r d w e l l was added i n 1972.

Cumulative i n j e c t i o n 8

through December,l979,was 7,108,653 b a r r e l s (2.9856 x 10 water.

g a l l o n s ) of

Two of t h e t h r e e w e l l s were s t i l l a c t i v e a t t h a t time.

Average

i n j e c t i o n p r e s s u r e s have ranged between 840 and 2,300 p s i . Casing Record:

I n j e c t i o n Well #12, T52N-R68W-11 bca, M e l l o t t Ranch F i e l d , Minnelusa U n i t , T o t a l Depth = 6930 f e e t .

Casing S i z e 8-5 /8"

Wt.

(#/£t) 24

Depth S e t

Cement

318'

180 sacks

Mike's Draw F i e l d (4,669,318 b b l s o i l , 5,270,713 MCF gas; 1974-79) S t e i n l e Unit A s i n g l e w e l l s a l t water d i s p o s a l system, operated by M i t c h e l l Energy Corporation, was s t a r t e d i n 1979, a t t h e S t e i n l e Unit of Mike's

Draw F i e l d

o own ship 36 N o r t h , Bange 70 West, Converse County).

The

i n j e c t i o n w e l l i s completed i n t h e Teckla sand a t a d e p t h of 6,782 f e e t . Through t h e f i r s t y e a r of i n j e c t i o n , 9,470 b a r r e l s (397,740 g a l l o n s ) of produced b r i n e were i n j e c t e d t o t h e Teckla sand. Casing Record:

S a l t Water D i s p o s a l W e l l #l-15, T36N-R70W-15 b d , ~ i k e ' s D r a w F i e l d , S t e i n l e U n i t , T o t a l Depth = 7371 f e e t .

Casing S i z e

Wt.

( m t )

Hole S i z e

Depth S e t

Cement

8-5/S"

24

12-1/4"

1042 '

500 s a c k s

5-1/2"

17,15.5

7-7/8"

7371'

300 s a c k s

M i l l e r Creek F i e l d (5,780,893 b b l s o i l , 4,365,122 MCF g a s ; 1959-79)

Twiford-Forney U n i t The M i l l e r Creek F i e l d Twiford-Forney U n i t i s t h e s i t e of a s i n g l e w e l l s a l t w a t e r d i s p o s a l system completed i n t h e Dakota sand a t a d e p t h of 5,984 f e e t .

D i s p o s a l of produced b r i n e s t a r t e d i n 1971, and

i n j e c t i o n r e p o r t s f i l e d i n J u n e , 1980, w i t h t h e O i l and Gas Commission, 7 i n d i c a t e t h a t 703,904 b a r r e l s (2.9563 x 1 0 g a l l o n s ) of s a l t water have been d i s p o s e d of t h r o u g h w e l l #5 s i n c e 1971. Casing Record:

S a l t Water D i s p o s a l Well #5, T51N-R68W-20 d a , Miller Creek F i e l d , Twiford-Forney U n i t , T o t a l Depth = 6062 feet.

Casing S i z e 7'I

Wt.

(///ft) 20,23

Depth S e t 6062'

Cement 100 s a c k s

Cordell Unit The C o r d e l l U n i t of Miller Creek F i e l d i s t h e s i t e of a n o t h e r s a l t w a t e r d i s p o s a l w e l l completed i n t h e Dakota sand.

The w e l l i s l o c a t e d

i n S e c t i o n 8 , Township 5 1 North, Bange 68 West, Crook County, and i s

completed a t a d e p t h of 5,890 f e e t .

Between t h e t i m e of t h e i n i t i a l

7 i n j e c t i o n s i n 1971, and J u n e , 1980, 1,157,706 b a r r e l s (4.8623 x 1 0 g a l l o n s ) of produced b r i n e were

i n j e c t e d a t a v e r a g e p r e s s u r e s between

210 and 2,275 p s i .

Casing Record:

S a l t Water D i s p o s a l W e l l #2, T51N-R68W-8, Miller Creek F i e l d , C o r d e l l U n i t , T o t a l Depth = 5968 f e e t .

Casing S i z e

Wt.

5-112"

(#/ft) 14,15

Depth S e t

Cement

5968'

100 s a c k s

Mobile Government Unit A t h i r d Miller Creek F i e l d s a l t w a t e r d i s p o s a l w e l l i s l o c a t e d a t t h e Mobil Government U n i t i n S e c t i o n 1 7 , Township 5 1 North, Range 68 West, Crook County.

The w e l l i s completed i n t h e Dakota sand and began

i n j e c t i o n of produced b r i n e i n 1972.

Cumulative i n j e c t i o n through

7 J u n e , 1980, w a s 564,882 b a r r e l s (2.3725 x 1 0 g a l l o n s ) of produced s a l t water.

Arcol Unit T e r r a Resources, I n c . began o p e r a t i o n of t h e f o u r t h s a l t w a t e r d i s p o s a l w e l l a t Miller Creek F i e l d i n 1978.

The w e l l i s l o c a t e d i n

t h e A r c o l U n i t of t h e f i e l d , i n S e c t i o n 1 6 , Township 5 1 North, Range 68 West.

Cumulative i n j e c t i o n i n t o t h e Dakota sand r e s e r v o i r a s of

J u l y , 1980, was 216,478 b a r r e l s (9,092,076 g a l l o n s ) of produced b r i n e . West Moorcroft F i e l d (6,119,999 b b l s o i l , 6,332,431 MCF g a s ; 1956-79) Newcastle U n i t The West Moorcroft F i e l d Newcastle U n i t a r e a c o v e r s 1,146 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d a l o n g t h e w e s t f l a n k of O i l B u t t e

a n t i c l i n e , an asymmetrical s t r u c t u r e on t h e extreme west edge of t h e Black H i l l s u p l i f t . The main o i l - b e a r i n g zone underlying West Moorcroft F i e l d i s t h e The Newcastle i n t h i s a r e a i s composed of sand-

Newcastle Sandstone.

s t o n e w i t h some s h a l e and ranges i n t h i c k n e s s between 45 and 60 f e e t . Overlying t h e Newcastle r e s e r v o i r i s a f o r m a t i o n a l cap of n e a r l y 200 The S k u l l Creek Shale l i e s immediately below t h e

f e e t of Mowry Shale. reservoir.

The Newcastle Unit waterflood p r o j e c t s t a r t e d i n 1971, and by 1976 included 11 w e l l s , seven of which were s t i l l a c t i v e a s of December, 1979. I n j e c t i o n r e p o r t s on f i l e a t t h e O i l and Gas Commission i n d i c a t e d t h a t cumulative i n j e c t i o n t o t h a t p o i n t was 8,512,293 b a r r e l s (3.5752 8

x 10

g a l l o n s ) of water from producing w e l l s i n t h e Dakota

a t a nearby f i e l d .

sand"

Average i n j e c t i o n p r e s s u r e s have n o t exceeded

1,780 p s i . A t e r t i a r y recovery water/polymer i n j e c t i o n p r o j e c t was undertaken by P l a n e t A s s o c i a t e s , I n c . , i n 1974, a t t h e Waters Unit of Moorcroft Field.

Of t h e p r o j e c t ' s n i n e w e l l s , only s i x a r e c u r r e n t l y (June, 1980)

active.

Casing Record: Casing S i z e

I n j e c t i o n Well #l, T52N-R68W-36 dd(ad), West Moorcroft F i e l d , Newcastle U n i t , T o t a l Depth = 4185 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-5/8"

24

12-1/4"

204'

150 sacks

Surface

4-1/2"

10.5

7-7/8"

4179'

125 sacks

Injection

Mule Creek F i e l d (3,356,598 b b l s o i l , 87,301 MCF g a s ; 1919-79) Argo U n i t Mule Creek o i l f i e l d i s s i a t u a t e d on a n e l o n g a t e d dome, t h e a x i s of which l i e s a l o n g t h e l i n e between Ranges 60 and 6 1 West and t h e c r e s t of which i s l o c a t e d a t about t h e c e n t e r of Township 39 North, Niobrara County.

The dome h a s over 200 f e e t of s t r u c t u r a l c l o s u r e .

I n 1919, Mule Creek F i e l d was d i s c o v e r e d when a producing o i l w e l l was completed i n t h e Lakota Sandstone.

I n j e c t i o n of produced Lakota

water f o r secondary o i l r e c o v e r y purposes began i n 1974.

Two w e l l s a r e

a c t i v e l y i n j e c t i n g a c c o r d i n g t o t h e most r e c e n t i n j e c t i o n r e p o r t s f i l e d

a t t h e O i l and Gas Commission by Tesoro Petroleum C o r p o r a t i o n (December, 1979).

7 The r e p o r t s i n d i c a t e t h a t 859,247 b a r r e l s (3.6088 x 1 0

g a l l o n s ) of w a t e r have been i n j e c t e d s i n c e t h e w a t e r f l o o d s t a r t e d . Reported a v e r a g e i n j e c t i o n p r e s s u r e s have n e v e r exceeded 558 p s i . Ziegler Unit The Minnelusa Formation d i s c o v e r y w e l l a t Mule Creek F i e l d was d r i l l e d i n 1929, and p e r f o r a t e d a n o i l r e s e r v o i r t h a t s p a n s 120 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of approximately 23 f e e t .

Water

i n j e c t i o n s t a r t e d i n 1959, u t i l i z i n g water from t h e Dakota sand. Minnelusa w a t e r f l o o d h a s been abandoned.

The

Cumulative i n j e c t i o n s t a t i s t i c s

7 f o r t h e Z i e g l e r U n i t f l o o d i n d i c a t e t h a t 536,442 b a r r e l s (2.2530 x 1 0 g a l l o n s ) of w a t e r were i n j e c t e d d u r i n g t h e l i f e of t h e p r o j e c t . Mush Creek F i e l d (12,059,785 b b l s o i l , 2,108,339 MCF g a s ; 1943-79) Mush Creek o i l f i e l d i s l o c a t e d j u s t t o t h e w e s t of S k u l l Creek F i e l d and j u s t e a s t of West Mush Creek F i e l d i n Township 44 North, Range 63 West, Weston County.

S t r u c t u r a l l y , t h e f i e l d i s s i t u a t e d on a

r e l a t i v e l y g e n t l e , t e r r a c e d monocline dipping two degrees westward from t h e Black H i l l s u p l i f t .

The Newcastle Sandstone, t h e lowest

member of t h e Upper Cretaceous s e r i e s , i s t h e only o i l - b e a r i n g format i o n a t Mush Creek F i e l d .

Hydrocarbon entrapment a p p a r e n t l y i s due

p r i m a r i l y t o l e n s i n g o r p e r m e a b i l i t y changes i n t h e Newcastle.

Although

t h e Newcastle Sandstone i s about 60 f e e t t h i c k i n t h i s a r e a , t h e o i l b e a r i n g p o r t i o n i s u s u a l l y found i n t h e lower p a r t of t h e formation and v a r i e s i n t h i c k n e s s from s i x t o 28 f e e t .

A t l e a s t f i v e s e p a r a t e sand

l e n s e s a r e known t o be o i l - b e a r i n g , b u t none a r e productive over t h e entire field.

F a c i e s changes from s h a l e t o sand and sand t o s h a l e a r e

very pronounced i n t h e Newcastle a t Mush Creek.

The discovery w e l l

was completed i n May, 1944, i n t h e Newcastle between 3,851 and 3,875 feet.

No commercial q u a n t i t i e s of o i l o r gas were found below t h e

Newcastle Sandstone. P i l o t water i n j e c t i o n p r o j e c t s were s t a r t e d by Texaco, I n c . , in 1950, and continued i n t e r m i t t e n t l y f o r s e v e r a l y e a r s .

L a t e r , Texaco

and H. T. Thorson formed a c o o p e r a t i v e p r o j e c t and J. G. Dyer and CRA, Inc., a l s o s t a r t e d projects.

Michaels Unit #4 Mush Creek F i e l d Michaels Unit i s l o c a t e d i n Township 44 North, Range 63 West, Weston County.

Water i n j e c t i o n t o t h e Newcastle Sand-

s t o n e a t a depth of 4,270 f e e t began i n 1975, through one w e l l .

Water

f o r t h e i n j e c t i o n p r o j e c t i s provided by supply w e l l s i n t h e Dakota and Lakota sands.

A s of December, 1979, 49,413 b a r r e l s (2.0753 x

6 10 g a l l o n s ) of water had been i n j e c t e d a t average p r e s s u r e s between 1,100 and 1,700 p s i .

Casing Record:

I n j e c t i o n Well #l,T44N-R63W-17 dd, Mush Creek F i e l d , Michaels Unit #4, T o t a l Depth = 4302 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

10-3/4"

42

125 '

5-1/2"

14

4270'

Purpose Surf a c e Injection

Rogers S t a t e 0-15723 Unit Under t h e o p e r a t i o n of t h e Toco Corporation, t h e Rogers Unit waterf l o o d was i n i t i a t e d during 1968, i n S e c t i o n s 10, 1 5 , and 16 of Township 44 North, Range 63 West, Weston County.

A l l b u t two of t h e e i g h t

i n j e c t i o n w e l l s t h a t were once a c t i v e , had been shut-in by December, 1979.

Cumulative i n j e c t i o n t o t h a t d a t e through a l l w e l l s was 3,857,092

8 b a r r e l s (1.62 x 10 g a l l o n s ) of Dakota and Lakota sand water.

Over t h e

l a s t 20 y e a r s of r e p o r t e d i n j e c t i o n a c t i v i t y a t t h e Rogers U n i t , average i n j e c t i o n p r e s s u r e s have ranged from 10 t o 1,705 p s i .

Buffalo-037775 Updike-Thorson Unit The Updike-Thorson Unit of Mush Creek F i e l d covers an a r e a of 1,650 a c r e s .

The Newcastle Sandstone, t h e o i l productive r e s e r v o i r

which u n d e r l i e s t h e u n i t and extends beyond t h e u n i t boundaries, has an average pay zone t h i c k n e s s of 5.6 f e e t .

The overlying cap rocks a r e

t h e B e l l e Fourche and Mowry s h a l e s . Water i n j e c t i o n f o r secondary o i l recovery was i n i t i a t e d i n September, 1950, under t h e j o i n t o p e r a t i o n of Texaco, Inc. and H. T. Thorson.

Since then, Texaco has s o l d i t s i n t e r e s t s a t Mush Creek.

The waterflood c u r r e n t l y i n v o l v e s only t h r e e a c t i v e w e l l s . o t h e r s have been shut-in.

Seven

I n j e c t i o n r e p o r t s from December, 1979,

8 i n d i c a t e t h a t 3,255,205 b a r r e l s (1.3672 x 10 g a l l o n s ) of water from

t h e Dakota and Lakota s a n d s have been i n j e c t e d t o t h e Newcastle reservoir since the project started.

I n j e c t i o n p r e s s u r e a v e r a g e s have

ranged from LO t o 2,240 p s i .

Casing Record:

I n j e c t i o n Well #7, T44N-R63W-21 bbc, Mush Creek F i e l d , Updike-Thorson U n i t , T o t a l Depth = 4332 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth

Cement

10-3 / 4"

32.75

163' K.B.

100 s a c k s

5-1/2"

14,17

4171' K.B.

150 s a c k s

Wade U n i t The Wade U n i t of Mush Creek F i e l d c o v e r s p o r t i o n s of S e c t i o n s 1 7 , 1 8 , and 1 9 i n Township 44 North, Range 63 West, Weston County.

The

u n i t i s o p e r a t e d by Toco C o r p o r a t i o n which began a secondary r e c o v e r y

water i n j e c t i o n p r o j e c t i n 1971, through t h r e e w e l l s p e r f o r a t e d i n t h e Newcastle Sandstone a t d e p t h s of 4,150 t o 4,250 f e e t . l a t e r expanded t o n i n e w e l l s .

The p r o j e c t was

Through December, 1979, 1,628,551 b a r r e l s

7 (6.8399 x 1 0 g a l l o n s ) of Dakota sand w a t e r had been i n j e c t e d over t h e d u r a t i o n of t h e p r o j e c t . i n f o r s i x years.

The o r i g i n a l t h r e e i n j e c t o r s have been s h u t -

Average i n j e c t i o n p r e s s u r e s have ranged from 150 t o

1,900 p s i . Casing Record:

I n j e c t i o n W e l l # l o , T44N-R63W-18 ddb, Mush Creek F i e l d , Wade U n i t , T o t a l Depth = 4505 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

10-3/4"

33

150'

5-1/2"

15

4505 '

Perforations

4432-58

Purpose Surf a c e

'

Injection

North Fork F i e l d (18,534,216 b b l s o i l , 8,418 MCF gas; 1951-79) C e l l a r s Ranch U n i t The Cellars Ranch Unit of North Fork F i e l d i s l o c a t e d i n Township 44, Range 82 West, Johnson County.

D i s p o s a l of s a l t w a t e r produced

w i t h o i l a t North Fork F i e l d s t a r t e d i n 1977, through a w e l l completed i n t h e Crow Mountain Formation a t a d e p t h of 5,684 f e e t .

Average

i n j e c t i o n p r e s s u r e s have ranged from 0 t o 900 p s i over t h e d u r a t i o n of the project.

Cumulative i n j e c t i o n through J a n u a r y , 1980, was

7 2,050,418 b a r r e l s (8.6117 x 1 0 g a l l o n s ) of produced b r i n e . Casing Record:

S a l t Water D i s p o s a l W e l l #3, TUN-R82W-24 a d , North Fork F i e l d , C e l l a r s Ranch U n i t , T o t a l Depth = 6845 feet.

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

10-3/4"

32.75

13-3/4"

521'

250 s a c k s

5-1/2"

14,15.5

8-3/4"

6844 '

135 s a c k s

Oedekoven F i e l d (2,372,804 b b l s o i l , 5,322,002 MCF g a s ; 1968-79) Muddy Sand U n i t The o n l y i n j e c t i o n p r o j e c t c u r r e n t l y o p e r a t i n g a t Oedekoven F i e l d , Township 55 North, Ranges 73 and 74 West, Campbell County, i s a t h r e e

w e l l s a l t w a t e r d i s p o s a l system which began i n 1971.

Cumulative i n j e c -

7 t i o n i n t o t h e Muddy Sandstone was 2,329,833 b a r r e l s (9.7853 x 10 g a l l o n s ) a s of December, 1979.

Average i n j e c t i o n p r e s s u r e s have ranged

from a vacuum ( g r a v i t y i n j e c t i o n ) t o 2,040 p s i .

The average p o r o s i t y

of t h e Muddy sand i n t h e Oedekoven a r e a i s 17.2 p e r c e n t .

O i l S p r i n g s F i e l d (12,971,118 MCF g a s i n s t o r a g e ; 1938-79) A n a t u r a l g a s s t o r a g e p r o j e c t o p e r a t e d by Northern Gas Company,

was s t a r t e d i n 1951, a t O i l S p r i n g s F i e l d .

The f i e l d is l o c a t e d i n

Township 23 North, Range 79 West, Carbon County.

S i n c e 1951, n a t u r a l

g a s h a s been i n j e c t e d i n t o t h e Sundance, Lakota, and Dakota sand reserv o i r s through f i v e i n j e c t i o n w e l l s . w e l l s were s t i l l a c t i v e .

A s of J a n u a r y , 1980, t h r e e of t h e

T o t a l i n j e c t i o n t o s t o r a g e f o r t h e y e a r 1979,

was 1,206,896 MCF.

OK F i e l d (12,111,663 b b l s o i l , 68,301 MCF g a s ; 1973-79) OK U n i t

S i n c e 1975, U n i v e r s a l Resources Company h a s been o p e r a t i n g a one

w e l l t e r t i a r y o i l r e c o v e r y p r o j e c t a t t h e OK u n i t of OK F i e l d .

The

f i e l d i s l o c a t e d i n Township 5 1 North, Range 70 West, Campbell County. The p r o j e c t i n v o l v e s t h e i n j e c t i o n of water/polymer s o l u t i o n i n t o t h e o i l producing Minnelusa Formation.

Cumulative i n j e c t i o n d a t a f o r

t h e OK F i e l d t e r t i a r y r e c o v e r y p r o j e c t were n o t a v a i l a b l e i n t h e f i l e s of t h e O i l and Gas Commission.

Olds F i e l d (21,422 b b l s o i l ; 1975-79) Tupper Unit Olds F i e l d , l o c a t e d i n Township 49 North, Range 65 West, Crook County, is c u r r e n t l y t h e s i t e of a s i n g l e w e l l s a l t w a t e r d i s p o s a l project.

I n j e c t i o n of produced b r i n e i n t o t h e B u t l e r sand w a s

i n i t a t e d i n 1977.

A s of June, 1980, 2,340 b a r r e l s (98,280 g a l l o n s )

of b r i n e had been i n j e c t e d .

Oregon Basin F i e l d (299,970,223 b b l s o i l , 149,901,637 MCF g a s ; 1912-79) Oregon Basin, approximately s i x m i l e s wide and 11 m i l e s long, i s t h e l a r g e s t s u r f a c e d e p r e s s i o n on t h e w e s t s i d e of t h e Bighorn Basin. Oregon Basin F i e l d was discovered i n 1912, when n a t u r a l gas was produced from a w e l l completed i n t h e Cloverly Formation.

The o i l and g a s

f i e l d i s s i t u a t e d i n Townships 50-52 North, Range 100 West, Park County, on t h e n o r t h and s o u t h Oregon Basin domes, which a r e s e p a r a t e d by a narrow s t r u c t u r a l s a d d l e .

I n 1927, o i l was discovered i n t h e Embar Formation and Tensleep Sandstone of t h e n o r t h dome. u n t i l 1943, i n t h e s o u t h dome.

Madison Limestone o i l was n o t discovered The n o r t h and s o u t h domes have indepen-

d e n t s t r u c t u r a l c l o s u r e s of about 500 f e e t and 900 f e e t , r e s p e c t i v e l y .

A f a u l t block a t t h e s o u t h end of t h e s o u t h dome appears t o b e t h e only f a u l t t h a t h a s a f f e c t e d hydrocarbon accumulation i n t h e lower p r o d u c t i v e formations.

A p l a n t o u n i t i z e development and o p e r a t i o n a t Oregon Basin F i e l d was approved by t h e S e c r e t a r y of t h e I n t e r i o r i n 1948.

An experimental

water i n j e c t i o n p r o j e c t was s t a r t e d i n 1956, on t h e n o r t h dome w i t h i n j e c t i o n i n t o t h e Embar r e s e r v o i r .

C u r r e n t l y (December, 1979), t h e r e

a r e t h r e e p r e s s u r e maintenance waterflood p r o j e c t s a c t i v e a t Oregon Basin Field--the

North Dome Embar-Tensleep,

Tensleep, and t h e South Dome Madison u n i t s .

t h e South Dome EmbarWater f o r t h e p r o j e c t s

i s provided by production w e l l s i n t h e Embar Formation, t h e Tensleep Sandstone, and t h e Madison Limestone.

Three Madison w e l l s d r i l l e d i n

1967, p r i m a r i l y f o r water supply, unexpectedly produced over 2,000 b a r r e l s of o i l p e r day.

North Embar-Tensleep Unit Water i n j e c t i o n i n t o t h e n o r t h dome Embar Formation was n o t resumed u n t i l 1962.

Tensleep Sandstone i n j e c t i o n began i n 1960.

The u n i t

p a r t i c i p a t i n g a r e a spans 3,715 a c r e s of f e d e r a l , s t a t e , and f e e land. The Embar sand has an average e f f e c t i v e pay t h i c k n e s s of 38 f e e t and a primary p e r m e a b i l i t y of 10 m i l l i d a r c i e s o r l e s s .

It i s assumed t h a t

r e s e r v o i r p e r m e a b i l i t y i s provided by a f r a c t u r e network.

The Tensleep

pay zone i s approximately 60 f e e t t h i c k w i t h a p e r m e a b i l i t y of about 150 m i l l i d a r c i e s .

Limited a v a i l a b l e c o r e d a t a i n d i c a t e t h a t t h e Embar

and Tensleep have average p o r o s i t i e s of 14 p e r c e n t and 16 p e r c e n t , respectively.

A s of J u l y , 1973, 46 of 52 e x i s t i n g i n j e c t i o n w e l l s

were a c t i v e , and 29 of t h e a c t i v e w e l l s were d u a l i n j e c t o r s p e r f o r a t e d i n both t h e Embar and Tensleep r e s e r v o i r s .

A t t h a t time, 228,585,465

9 b a r r e l s (9.6006 x 10 g a l l o n s ) of water had been i n j e c t e d s i n c e t h e s t a r t of t h e p r o j e c t .

Average i n j e c t i o n p r e s s u r e s have ranged from 0

t o 560 p s i . A water q u a l i t y a n a l y s i s was performed on water i n j e c t e d a t t h e

F r i s b y A-3 i n j e c t i o n w e l l and i n d i c a t e d extremely high s u l f a t e c o n c e n t r a t i o n s (3,450 mg/l).

Casing Record:

I n j e c t i o n Well Atherly #5, T52N-R100W-33 ccb, North Oregon Basin F i e l d , Embar-Tensleep U n i t , T o t a l Depth = 3930 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

13-318"

48

17-1/2"

8-518''

32

11"

Depth S e t

Cement

519 '

625 sacks

3930'

440 s a c k s

South Embar-Tensleep Unit Water i n j e c t i o n i n t o t h e Tensleep and Embar Formations of t h e south dome of Oregon Basin F i e l d began i n 1958 and 1963, r e s p e c t i v e l y .

The

South Embar-Tensleep Unit covers 5,862 a c r e s of f e d e r a l , p r i v a t e , and uncommitted land.

F i f t y - s i x of t h e 66 a c t i v e i n j e c t o r s i n t h e South

Embar-Tensleep Unit a r e d u a l l y p e r f o r a t e d i n both formations. w e l l s have been temporarily shut-in.

Eight

Cumulative i n j e c t i o n through

9 J u l y , 1973, was 201,640,225 b a r r e l s (8.4689 x 10 g a l l o n s ) of produced water from t h e Madison Limestone, Embar Formation, and Tensleep Sandstone. Casing Record:

I n j e c t i o n Well Brendel # 4 , T50N-R100W-7 aba, South Oregon Basin F i e l d , Embar-Tensleep U n i t , T o t a l Depth = 4665 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement 175 sacks (Type "GI' )

9-518"

32.3

13-3 14"

233'

5-112"

15.5

7-7 /8"

4663'

300 sacks (50-50 pozmix)

South Madison Unit The Madison Unit of South Oregon Basin F i e l d i n c l u d e s 2,392 a c r e s of f e d e r a l and p r i v a t e l a n d i n S e c t i o n s 31 and 32 of Township 5 1 North, Range 100 West, Park County.

One of two water i n j e c t i o n w e l l s was

a c t i v e l y i n j e c t i n g produced water from t h e Madison Limestone, Embar Formation, and Tensleep Sandstone.

I n j e c t i o n r e p o r t s were n o t a v a i l a b l e

f o r t h e Madison Unit a t t h e O i l and Gas Commission.

Osage F i e l d (25,271,901 b b l s o i l , 122,123 MCF gas; 1919-79) Osage F i e l d i s l o c a t e d i n n o r t h - c e n t r a l Weston County, approximately 1 5 m i l e s northwest of Newcastle, Wyoming.

The f i r s t o i l

w e l l i n t h e f i e l d was completed i n 1919, i n t h e Graneros Shale.

One

year l a t e r , a w e l l was completed i n t h e Newcastle (Muddy) Sandstone. The f i e l d i s l o c a t e d on a west-dipping monocline, which l i e s on t h e southwest f l a n k of t h e Black H i l l s u p l i f t .

The s t r u c t u r e c o n t a i n s

a number of p i t c h e s and t e r r a c e s w i t h d i p s ranging from 1 t o 10 degrees. The most important producing formation i s t h e Lower Cretaceous Newcastle (Muddy) sand i n which o i l h a s accumulated i n s t r a t i g r a p h i c traps.

The major a q u i f e r s w i t h i n t h e Osage a r e a a r e t h e Greenhorn

Shale, t h e Dakota-Lakota sands, and t h e Madison Limestone. (Muddy) Sandstone i s a f i n e - t o medium-grained w i t h some s i l t s t o n e and s h a l e .

The Newcastle

l e n t i c u l a r sandstone

The formation t h i c k n e s s i n t h e Osage

a r e a ranges between 20 and 100 f e e t .

Detailed reservoir studies

i n d i c a t e d t h a t p e r m e a b i l i t y v a r i e d thorughout t h e f i e l d and p r e s e n t e d t h e p o s s i b i l i t y t h a t s e v e r a l r e s e r v o i r s might b e p r e s e n t . There a r e e l e v e n s e p a r a t e u n i t s w i t h i n t h e Osage and Osage West F i e l d s t h a t were o p e r a t i n g a c t i v e waterflood p r o j e c t s a s of December, 1979.

They a r e t h e Coronado Shallow Lens U n i t , t h e Somers Area U n i t ,

t h e S t a t e Waterflood U n i t , t h e J u n i p e r Newcastle U n i t , t h e Osage J u n i p e r Area U n i t , t h e Bradley Newcastle U n i t , t h e Mush Creek Extension U n i t , t h e Osage U n i t , t h e Buffalo Lease U n i t , t h e Osage West U n i t , and t h e Osage Miscellaneous Unit.

Each of t h e u n i t s i s i n j e c t i n g w a t e r i n t o

t h e m u l t i p l e benches of t h e Newcastle (Muddy) sand and t h e f r a c t u r e d Nefsy S h a l e which o v e r l i e s t h e Newcastle. The f i r s t p i l o t w a t e r f l o o d began i n 1959.

By 1968, Coronado O i l

Company, J u n i p e r O i l Company, B u t t e s Resources Company, and William Blake were o p e r a t i n g water i n j e c t i o n p r o j e c t s a t Osage F i e l d .

Reserve O i l Company s t a r t e d a one w e l l s a l t water d i s p o s a l system a t Osage F i e l d i n 1977.

A s of June, 1980, 9,480 b a r r e l s (398,160

g a l l o n s ) of produced b r i n e had been i n j e c t e d i n t o t h e Newcastle Sands t o n e a t an average i n j e c t i o n p r e s s u r e of l e s s than 700 p s i . J u n i p e r (Newcastle Sand) Unit The J u n i p e r Unit of Osage F i e l d covers 2,432.52 a c r e s i n Township 46 North, Ranges 63 and 64 West, Weston County, Wyoming.

It i s

s i t u a t e d h i g h on t h e g e n t l e , n o r t h e a s t e r n f l a n k of t h e Powder River Basin, southwest of t h e Black H i l l s u p l i f t . The Newcastle r e s e r v o i r of t h e J u n i p e r Unit i n c l u d e s 2,400 a c r e s w i t h an average pay zone t h i c k n e s s of 5 f e e t .

P o r o s i t y and p e r m e a b i l i t y

measurements were taken from c o r e a n a l y s e s a t 27 of t h e 42 i n j e c t i o n w e l l s a t one f o o t i n t e r v a l s w i t h i n t h e productive pay zone of each w e l l . The measurements were averaged f o r each w e l l and then averages a t each of t h e 27 w e l l s were a g a i n averaged t o a r r i v e a t average p o r o s i t y and p e r m e a b i l i t y f i g u r e s f o r t h e Newcastle sand of t h e J u n i p e r Unit of 22.8 p e r c e n t and 44.2 m i l l i d a r c i e s , r e s p e c t i v e l y .

A water i n j e c t i o n

p r o j e c t , which included s i x i n j e c t i o n w e l l s , began i n 1966, and has s i n c e been expanded t o 42 a c t i v e i n j e c t o r s a s of December, 1979.

Water

f o r t h e p r o j e c t i s provided by a Madison supply w e l l i n Township 46 North, Range 64 West, S e c t i o n 23.

T o t a l cumulative i n j e c t i o n i n t h e

8 42 w e l l s h a s been 11,286,743 b a r r e l s (4.7404 x 10 g a l l o n s ) .

Casing Record:

I n j e c t i o n Well 12-3W, T46N-R64W-25 adb, Osage F i e l d , J u n i p e r ( ~ e w c a s t l eSand) U n i t , T o t a l Depth = 1505 f e e t .

Casing S i z e

Wt.

7" 2-7/8"

(#/ft)

Hole S i z e

Depth S e t

'+

17

8-3/4"

100

6.4

6-1/4"

1505'

Cement 25 sacks 80 sacks

Osage J u n i p e r Area The Osage J u n i p e r Area i s l o c a t e d i n Township 46 North, Ranges 63 and 64 West, Weston County. As of December, 1979, t h e w a t e r f l o o d p r o j e c t o p e r a t e d by B u t t e s Resources Company i n c l u d e d e i g h t a c t i v e i n j e c t o r s . of t h e Newcastle Sandstone began i n 1968.

Waterflooding

The Newcastle sand h a s a n

a v e r a g e p o r o s i t y and p e r m e a b i l i t y of 23 p e r c e n t and 25.9 m i l l i d a r c i e s , respectively, i n the Juniper area. The w a t e r s u p p l y f o r t h e i n j e c t i o n f i e l d i s provided by t h e Madison Limestone v i a t h e same w e l l t h a t s u p p l i e s t h e J u n i p e r Newcastle U n i t , t h e Osage West U n i t and t h e Osage Bradley U n i t i n Township 46 North, Range 64 West, S e c t i o n 23.

Cumulative i n j e c t i o n t o December,

8 1979, was 2,503,250 b a r r e l s (1.0513 x 10 g a l l o n s ) of w a t e r .

Casing Record:

Lemin Lease I n j e c t i o n Well W-1, ~46N-R63W-19 c ( b c ) , Osage J u n i p e r Area, Osage F i e l d , T o t a l Depth = 1455 feet

.

Casing S i z e

7"

Wt.

(///ft) 20

Hole S i z e

Depth S e t

Cement

9

101'

30 s a c k s (regular)

6"

1447 '

60 s a c k s (50-50 pozmix) (2% g e l , 10% ~ a C 1 )

Osage West U n i t The Osage West U n i t i s l o c a t e d between t h e Osage S t a t e Waterflood t o t h e e a s t and F i d d l e r Creek F i e l d t o t h e w e s t .

The u n i t c o v e r s a n

a r e a of 2,760 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d .

It i s

s i t u a t e d on a s t e e p , westward d i p p i n g homocline, i n c o n t r a s t t o t h e much more g e n t l e d i p a s s o c i a t e d w i t h t h e r e s t of Osage F i e l d updip t o t h e e a s t and F i d d l e r Creek F i e l d downdip t o t h e w e s t .

A t t h e extreme

s o u t h e r n end of t h e u n i t , t h e beds s t r i k e n o r t h w e s t and d i p southwest a t a b o u t 20 d e g r e e s .

Northward, t h e s t r i k e swings toward t h e n o r t h ,

d i p p i n g w e s t e r l y a t about 1 4 d e g r e e s . An unconformity between t h e Newcastle sand and u n d e r l y i n g beds h a s a n i r r e g u l a r s u r f a c e r e s u l t i n g i n a Newcastle sand t h i c k n e s s which v a r i e s between 28 and 79 f e e t , w i t h t h i c k n e s s g e n e r a l l y g r e a t e r toward t h e south.

Depth t o t h e Newcastle sand w i t h i n t h e u n i t r a n g e s from

1,900 f e e t t o 3,800 f e e t .

The u n i t boundary h a s been s e l e c t e d on t h e

b a s i s of a s t r a t i g r a p h i c p i n c h o u t of t h e Newcastle sand r e s e r v o i r . The Osage West r e s e r v o i r i n c l u d e s 1 , 6 0 0 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of 8 f e e t .

P o r o s i t y and p e r m e a b i l i t y measurements

t a k e n from t h r e e c o r e a n a l y s e s of w e l l s i n t h e Osage West U n i t i n d i c a t e a n a v e r a g e p o r o s i t y of 1 8 . 1 p e r c e n t and a n a v e r a g e p e r m e a b i l i t y of 87.7 m i l l i d a r c i e s f o r t h e r e s e r v o i r .

Fresh water f o r the i n j e c t i o n

p r o j e c t , which began i n 1965, w i t h t h r e e w e l l s , i s s u p p l i e d by a Madison Limestone w e l l i n Township 46 North, Range 64 West, S e c t i o n 2 3 .

The

w a t e r f l o o d h a s been expanded t o i n c l u d e 1 8 w e l l s , 1 4 a c t i v e and 4 temporarily shut-in,

a s of December, 1979.

Cumulative i n j e c t i o n t o t h a t

8 d a t e was 10,714,745 b a r r e l s (4.500 x 10 g a l l o n s ) of w a t e r .

Osage Bradley Newcastle U n i t The Bradley Newcastle U n i t c o v e r s a n a r e a of 880 a c r e s of f e d e r a l and p r i v a t e l a n d l o c a t e d approximately 20 m i l e s n o r t h w e s t of Newcastle, Wyoming.

The u n i t a r e a i s n e a r t h e c e n t e r of Osage F i e l d .

B u t t e s Resources Company, o p e r a t o r of t h e u n i t , i n i t i a t e d t h e w a t e r i n j e c t i o n p r o j e c t i n 1969.

Madison Limestone w a t e r from t h e w e l l

used i n t h e Osage West, J u n i p e r Area and J u n i p e r Newcastle Sand d n i t s

a l s o p r o v i d e s t h e w a t e r s u p p l y f o r t h e Bradley U n i t w a t e r f l o o d .

By

December, 1979, 25 w e l l s were a c t i v e l y i n j e c t i n g i n t o t h e Newcastle reservoir. The a v e r a g e p o r o s i t y of t h e Newcastle i n t h e Bradley a r e a i s 21.1 p e r c e n t and p e r m e a b i l i t y a v e r a g e s 5 1 m i l l i d a r c i e s .

Cumulative w a t e r

i n j e c t e d i n t o t h e r e s e r v o i r t o t h e end of 1979, was 5,140,719 b a r r e l s 8 (2.1591 x 1 0 g a l l o n s )

.

Osage S t a t e Waterflood The Osage S t a t e Waterflood U n i t i s l o c a t e d i n t h e e a s t - c e n t r a l p o r t i o n of Township 46 North, Range 64 West, Weston County. p r o j e c t h a s a l s o been c a l l e d t h e Coronado Deep Lens P r o j e c t .

This The deep

l e n s e i s a c t u a l l y a s i n g l e sand b a r which g r a d e s i n t o s h a l e i n a l l directions.

The r e s e r v o i r c o v e r s a n a r e a of about 960 a c r e s w i t h an

a v e r a g e pay t h i c k n e s s of approximately 10 f e e t .

Analyses of c o r e s from

1 3 w e l l s completed i n t h e r e s e r v o i r showed a v e r a g e s of 23.3 p e r c e n t p o r o s i t y and 428 m i l l i d a r c i e s p e r m e a b i l i t y . When t h e w a t e r f l o o d p r o j e c t i n t h e S t a t e U n i t began i n 1959, water f o r i n j e c t i o n was s u p p l i e d by a w e l l 1,800 f e e t deep i n t h e Lakota Sandstone.

From 1 9 6 1 t o t h e p r e s e n t , i n j e c t i o n w a t e r h a s been provided by

a w e l l completed i n t h e Madison Limestone (Township 46 North, Range 64 West, S e c t i o n 1 3 c c a ) . (1.0884 x 10' began.

A cumulative t o t a l of 25,913,328 b a r r e l s

g a l l o n s ) of w a t e r have been i n j e c t e d s i n c e t h e p r o j e c t

Casing Record:

Casing Size 2-3/8"

S t a t e Lease W e l l 1-6, T46N-R64W-14 c a c , Osage F i e l d , S t a t e Waterflood U n i t , T o t a l Depth = 1962 f e e t .

Wt. (f/ft)

Amount / Make

Kind of Shoe

1983.51/ Youngstown

Float & Guide

Grade

4.6

5-55

Perforations

Purpose

1896.5-1906

Injection Casing

Osage Somers U n i t The Somers U n i t i s l o c a t e d a t t h e e a s t end of Osage F i e l d n o r t h w e s t of Newcastle, Wyoming.

The Newcastle sand zones of t h e Somers Area

a r e found a t v e r y s h a l l o w d e p t h s (217 t o 528 f e e t ) r e l a t i v e t o o t h e r u n i t s a t Osage F i e l d .

The cap r o c k o v e r t h e Newcastle sand i n t h i s a r e a

and o t h e r s w i t h i n t h e Osage F i e l d i s t h e Mowry S h a l e , a s i l i c e o u s s h a l e a b o u t 200 f e e t t h i c k i n t h e Newcastle Area. Water i n j e c t i o n i n t o t h e Newcastle sand began i n 1972, w i t h t h e completion of 1 7 i n j e c t i o n w e l l s .

Water i s s u p p l i e d t o t h e i n j e c t o r s

from a Madison s u p p l y w e l l l o c a t e d i n Township 46 North, Range 63 West, S e c t i o n 17 cb.

Between t h e s t a r t of t h e p r o j e c t and December, 1979,

7 1,999,846 b a r r e l s of w a t e r (8.3994 x 10 g a l l o n s ) had been i n j e c t e d . Twenty w e l l s were a c t i v e l y i n j e c t i n g a s of t h a t d a t e .

Casing Record:

Casing S i z e 2-7/8"

S t a t e Lease I n j e c t i o n W e l l I-9W, T46N-R63W-16 F i e l d , Somers U n i t , T o t a l Depth = 285 f e e t . Wt.

(#/ft) 6.5

Hole S i z e 6-1/4"

Depth S e t 283'

c a b , Osage

Cement

Purpose

55 s a c k s

Water injection

Coronado Shallow Lens U n i t The a r e a covered by t h e Coronado Shallow Lens r e s e r v o i r i s 1 , 2 4 0 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of 8 f e e t .

Average r e s e r v o i r

p o r o s i t y and p e r m e a b i l i t y a r e 22 p e r c e n t and 55 m i l l i d a r c i e s , r e s p e c t i v e l y .

I n t h i s a r e a , t h e Newcastle Sandstone i s a t a n t o g r a y , f i n e - t o v e r y fine-grained, mottled, clay-filled,

cross-bedded sand.

The Coronado Shallow Lens w a t e r f l o o d p r o j e c t s t a r t e d i n 1960, s u p p l i e d by w a t e r from two w e l l s i n t h e Lakota Sandstone.

A Madison

s u p p l y w e l l i n Township 46 North, Range 63 West, S e c t i o n 17 cb h a s provided t h e w a t e r s u p p l y s i n c e i t s completion i n 1969. The i n j e c t i o n w e l l s of t h e Coronado Shallow Lens U n i t a r e p r o t e c t e d w i t h 2-7/8 i n c h c a s i n g r u n t o t h e t o t a l d e p t h of t h e h o l e , p e r f o r a t e d i n t h e Newcastle Sandstone and cemented 300 f e e t above t h e p e r f o r a t i o n s . Of t h e 78 i n j e c t o r s i n t h e u n i t , 68 were a c t i v e a s of December, 1979, and t h e c u m u l a t i v e t o t a l of w a t e r i n j e c t e d s i n c e 1960, was 12,217,381 8 b a r r e l s (5.1313 x 1 0 g a l l o n s ) .

B u f f a l o 028328A Lease The B u f f a l o Lease of t h e Osage F i e l d i s l o c a t e d i n S e c t i o n s 22 and 23 of Township 46 North, Range 64 West, Weston County.

The Newcastle

Sandstone r e s e r v o i r i s e x t r e m e l y t h i n i n t h i s a r e a r a n g i n g from 8 t o 1 3 f e e t i n t h i c k n e s s a t a d e p t h of 1,700 t o 2,200 f e e t .

Average p o r o s i t y

and p e r m e a b i l i t y measurements from c o r e a n a l y s e s of t h r e e w e l l s i n t h e u n i t were 1 9 . 1 p e r c e n t and 2 t o 87.7 m i l l i d a r c i e s , r e s p e c t i v e l y . The w a t e r f l o o d i n g of t h e B u f f a l o Lease began i n 1969, and c u r r e n t l y (December, 1979) i n v o l v e s 1 4 i n j e c t i o n wells--10

a c t i v e and 4 s h u t - i n .

Cumulative i n j e c t i o n t o t a l s were n o t a v a i l a b l e .

Osage U n i t The Osage U n i t of Osage F i e l d i s c o n f i n e d t o S e c t i o n 11, Tbwnship 46 North, Range 64 West, Weston County.

Water i n j e c t i o n i n t o t h e Newcastle Sandstone of t h e Osage U n i t began i n 1975, through two w e l l s .

The proposed c o n f i g u r a t i o n f o r t h e

w e l l s was a f i v e - s p o t p a t t e r n u t i l i z i n g a producing w e l l a t t h e c e n t e r

and f o u r i n j e c t o r s a t t h e c o r n e r s of each 40 a c r e t r a c t . 7 Between 1975 and December, 1979, 276,472 b a r r e l s (1.1612 x 1 0 g a l l o n s ) of w a t e r were i n j e c t e d i n t o t h e Newcastle Sandstone. P a i n t e r R e s e r v o i r (1,785,407 b b l s o i l , 9,306,755 MCF g a s ; 1977-79) Painter Reservoir Unit P a i n t e r R e s e r v o i r , l o c a t e d i n Township 16 North, Ranges 119 and 120 West, U i n t a County, i s c u r r e n t l y t h e s i t e of two i n j e c t i o n p r o j e c t s . The f i r s t i s a g a s i n j e c t i o n p r o j e c t , s t a r t e d i n 1978, under t h e operat i o n of Chevron, U.S.A.

Twelve w e l l s a r e i n v o l v e d i n t h e i n j e c t i o n of

n i t r o g e n g a s i n t o t h e Nugget Sandstone.

The purpose of t h e n i t r o g e n

i n j e c t i o n p r o j e c t i s t o augment t h e r e s e r v o i r p r e s s u r e , t h e r e b y i n c r e a s i n g o i l p r o d u c t i o n from t h e Nugget.

Cumulative n i t r o g e n i n j e c t i o n

through J u n e , 1980, was 38,435 MCF. The second a c t i v e i n j e c t i o n p r o j e c t a t P a i n t e r R e s e r v o i r i s a two w e l l s a l t w a t e r d i s p o s a l system t h a t was p u t i n t o o p e r a t i o n i n 1979. Produced Nugget Sandstone b r i n e s a r e s e p a r a t e d from produced o i l and i n j e c t e d t o t h e Nugget a t d e p t h s between 9,500 and 10,500 f e e t . Cumulative i n j e c t i o n d a t a were u n a v a i l a b l e a t t h e t i m e of t h i s w r i t i n g .

Casing Record:

S a l t Water D i s p o s a l W e l l #32-9B, Tl6N-R119W-9, P a i n t e r R e s e r v o i r F i e l d , P a i n t e r R e s e r v o i r U n i t , T o t a l Depth = 9800 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

13-318"

54.5

17-1/2"

811'

1500 s a c k s

9-518"

43.5

12-114"

7618'

4700 s a c k s

P a t r i c k Draw F i e l d (1,978,492 b b l s o i l , 10,478,344 MCF g a s ; 1959-79) Monell U n i t The Monell U n i t of P a t r i c k Draw F i e l d c o v e r s 10,120 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d i n Townships 1 8 and 1 9 North, Ranges 98 and 99 West, Sweetwater County.

I n 1959, o i l was d i s c o v e r e d i n t h e

Almond s a n d s of P a t r i c k Draw F i e l d . The Almond sand r e s e r v o i r i s found a t a n a v e r a g e d e p t h of 4,700 f e e t i n t h e Monell U n i t a r e a and a v e r a g e r e s e r v o i r p o r o s i t y and permea b i l i t y a r e 20 p e r c e n t and 33 m i l l i d a r c i e s , r e s p e c t i v e l y .

The Almond

r e s e r v o i r c o v e r s a n a r e a of approximately 7,500 a c r e s w i t h a n a v e r a g e n e t sand t h i c k n e s s of 2 1 f e e t . I n J u l y , 1963, a one w e l l p i l o t w a t e r i n j e c t i o n p r o j e c t was i n i t i a t e d i n o r d e r t o d e t e r m i n e t h e w a t e r s e n s i t i v i t y of t h e Almond sand.

It was determined t h a t s h a l e s w i t h i n t h e r e s e r v o i r c o n t a i n e d

k a o l i n i t e and i l l i t e , m i n e r a l s known f o r t h e i r tendency t o d e f l o c c u l a t e when i n c o n t a c t w i t h w a t e r of a n i n c o m p a t i b l e chemical n a t u r e .

The

movement of d e f l o c c u l a t e d s h a l e p a r t i c l e s can c a u s e mechanical plugging of p o r e s p a c e s w i t h i n t h e r e s e r v o i r . The w a t e r i n j e c t i o n p r o j e c t was expanded t o a f u l l s c a l e w a t e r f l o o d i n 1968, and by J u n e , 1979, 77 wells were i n j e c t i n g w a t e r from s u p p l y w e l l s i n t h e Lance Formation and Fox H i l l s Sandstone.

Water from b o t h

f o r m a t i o n s h a s been shown, through l a b and f i e l d t e s t i n g , t o b e c o m p a t i b l e w i t h w a t e r of t h e Almond r e s e r v o i r , t h e r e b y d e c r e a s i n g t h e p o t e n t i a l f o r s h a l e d e f l o c c u l a t i o n and p l u g g i n g of t h e r e s e r v o i r ' s e f f e c t i v e p o r o s i t y . Cumulative i n j e c t i o n through J u n e , 1979, amounted t o 68,947,912 b a r r e l s 9 (2.8958 x 1 0 g a l l o n s ) of w a t e r .

I n j e c t i o n p r e s s u r e s have averaged

between 0 and 2,450 p s i d u r i n g t h e p r o j e c t ' s l i f e t i m e .

E s t i m a t e s of

t h e o r i g i n a l o i l i n p l a c e w i t h i n t h e Almond r e s e r v o i r were 133,112,145 barrels.

Through primary r e c o v e r y and secondary r e c o v e r y by g a s

i n j e c t i o n , i t was e s t i m a t e d t h a t 27,953,550 b a r r e l s of o i l would b e r e c o v e r e d from t h e r e s e r v o i r .

A d d i t i o n a l r e c o v e r y of o i l a s a r e s u l t of

w a t e r i n j e c t i o n t o t h e Almond sand w a s expected t o t o t a l 12,046,450 barrels. Gas i n j e c t i o n p r e s s u r e maintenance p r o j e c t s , which were s t a r t e d i n b o t h t h e Arch and Monell u n i t s of P a t r i c k Draw F i e l d i n 1961 and 1962, r e s p e c t i v e l y , have been s h u t - i n f o r a t l e a s t two y e a r s .

A t t h e Monell

U n i t , 51,884,402 MCF of n a t u r a l g a s were i n j e c t e d i n t o t h e Almond sand a t d e p t h s between 4,180 and 4,402 f e e t through f i v e w e l l s .

Injection

p r e s s u r e s ranged between 35 and 2,425 p s i , on t h e average.

The Arch

U n i t g a s i n j e c t i o n p r o j e c t i n v o l v e s o n l y two w e l l s which i n j e c t e d a c u m u l a t i v e t o t a l of 36,556,902 MCF a t a v e r a g e p r e s s u r e s between 750 and 2,358 p s i . A s a l t w a t e r d i s p o s a l p r o j e c t o p e r a t e d by E l Paso P r o d u c t s , I n c . ,

began i n 1974, a t t h e Monell U n i t of P a t r i c k Draw F i e l d .

The s o l e

i n j e c t o r i s l o c a t e d i n S e c t i o n 1 3 , Township 1 8 North, Range 99 West, and

7 a s of J u n e , 1980, had i n j e c t e d 2,075,236 b a r r e l s (8.7159 x 1 0 g a l l o n s ) of produced b r i n e i n t o t h e Fox H i l l s Sandstone a t a d e p t h of 3,905 f e e t . Casing Record:

I n j e c t i o n Well 1/19, T19N-R99W-25 c d , P a t r i c k Draw F i e l d , Monell U n i t , T o t a l Depth = 4930 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

8-5 / 8"

24

258'

130 s a c k s

5-1/2"

15.5

4925 '

90 s a c k s

Purpose Surf a c e Injection

Water Q u a l i t y A n a l y s i s :

(Fox H i l l s w a t e r s u p p l y w e l l , T18N-R99W-3 P e r f o r a t e d 3108-3311 f e e t )

pH = 7.8 TDS

=

Na

64,783 mg/l

=

da,

24,818 mg/l

C 1 = 39,000 mg/l

P i c k r e l Ranch F i e l d (1,306,127 b b l s o i l , 25,596 MCF g a s ; 1965-79) Minnelusa U n i t O i l p r o d u c t i o n a t t h e P i c k r e l Ranch F i e l d Minnelusa U n i t s t a r t e d

i n 1965, w i t h t h e completion of a 9,000 f o o t w e l l i n t h e Pennsylvanian Minnelusa Formation. County (T48N-R69W).

The f i e l d i s l o c a t e d i n e a s t - c e n t r a l Campbell The Minnelusa U n i t p a r t i c i p a t i n g a r e a c o v e r s

1,110.88 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d and i s c u r r e n t l y under a n 80 a c r e w e l l s p a c i n g o r d e r .

The p r o d u c t i v e zone of t h e Minne-

l u s a r e s e r v o i r i s a s t r a t i g r a p h i c t r a p bounded by a p e r m e a b i l i t y p i n c h o u t on t h e n o r t h and e a s t and by a n o i l - w a t e r

c o n t a c t on t h e s o u t h w e s t .

The p e r m e a b i l i t y p i n c h o u t i s b e l i e v e d t o have r e s u l t e d from t h e development of a c h a n n e l i n t h e Minnelusa p a l e o s u r f a c e and t h e subisequent i n f i l l i n g w i t h Opeche S h a l e .

Average r e s e r v o i r p o r o s i t y and p e r m e a b i l i t y

a r e 1 6 . 1 p e r c e n t and 126 m i l l i d a r c i e s , r e s p e c t i v e l y . I n f l u x of w a t e r t o t h e Minnelusa r e s e r v o i r i s b e l i e v e d t o b e l i m i t e d due t o t h e d r o p i n r e s e r v o i r p r e s s u r e a s s o c i a t e d w i t h p r o d u c t i o n and t o t h e f a c t t h a t water c u t s of produced o i l have remained c o n s t a n t . For t h e s e r e a s o n s , i t i s thought t h a t t h e o i l - w a t e r c o n t a c t h a s n o t moved up s t r u c t u r e any a p p r e c i a b l e d i s t a n c e . Water i n j e c t i o n t o t h e Minnelusa r e s e r v o i r s t a r t e d i n 1970, u t i l i z i n g f r e s h w a t e r s u p p l i e d by w e l l s i n t h e Fox H i l l s Sandstone. Three i n j e c t i o n w e l l s have been employed d u r i n g t h e p r o j e c t ; however, o n l y one w e l l remained a c t i v e a s of October, 1979.

Cumulative

8 i n j e c t i o n t o t h a t d a t e was 5,480,244 b a r r e l s (2.3017 x 10 g a l l o n s ) of Average i n j e c t i o n p r e s s u r e s r e p o r t e d by t h e o p e r a t o r , M. J .

water.

M i t c h e l l , have ranged from a vacuum t o a maximum of 2,550 p s i . Casing Record: Casing S i z e

I n j e c t i o n Well # 4 , T48N-R69W-18 d d ( c d ) , P i c k r e l Ranch F i e l d , Minnelusa U n i t , T o t a l Depth = 9057 f e e t . (#/ft)

Wt.

8-518"

24

5-112"

Cement

Purpose

Hole S i z e

Depth S e t

12-114"

274'

200 f t3

Surface

7-7/8"

9057 '

350 f t 3

Injection

15.5,17,23

P i t c h f o r k F i e l d (22,553,947 b b l s o i l ; 1930-79) Pitchfork Unit Husky O i l Company i s c u r r e n t l y (December, 1979) o p e r a t i n g a s i x

w e l l s a l t w a t e r d i s p o s a l system a t P i t c h f o r k F i e l d .

The w e l l s a r e

l o c a t e d i n S e c t i o n s 2 , 11, and 1 4 , Township 48 North, Range 102 West, P a r k County. are

The d i s p o s a l p r o j e c t s t a r t e d i n 1972.

Produced b r i n e s

- . i n j e c t e d t o t h e Tensleep sand r e s e r v o i r , which o c c u r s a t a n

approximate d e p t h of 4,000 f e e t .

The c u m u l a t i v e volume of s a l t w a t e r

i n j e c t e d between 1972 and June, 1979, was 64,396,021 b a r r e l s (2.7046 x 9 10 g a l l o n s ) .

A l l s i x of t h e w e l l s were s t i l l a c t i v e l y i n j e c t i n g

a c c o r d i n g t o J u n e , 1979, i n j e c t i o n r e p o r t s . Casing Record:

S a l t Water D i s p o s a l W e l l #16, T48N-R102W-2 P i t c h f o r k F i e l d , P i t c h f o r k Unit.

Casing S i z e 7"

Wt.

(#/£t) 17

Depth S e t 3996'

cd,

Cement 150 s a c k s

P l e a s a n t V a l l e y Ranch F i e l d (712,997 b b l s o i l ; 1963-79) Hep t n e r U n i t P l e a s a n t V a l l e y Ranch F i e l d was d i s c o v e r e d i n 1963, when a produci n g o i l w e l l was completed i n t h e Minnelusa Formation.

The f i e l d i s

l o c a t e d i n Township 5 1 N o r t h , Range 69 West, Campbell County.

In the

P l e a s a n t V a l l e y Ranch a r e a , t h e a v e r a g e p o r o s i t y and p e r m e a b i l i t y of t h e Minnelusa producing zone are 11.1 t o 1 4 p e r c e n t and 29 m i l l i d a r c i e s , respectively. A s m a l l s c a l e w a t e r f l o o d p r o j e c t was s t a r t e d a t t h e Heptner U n i t of P l e a s a n t V a l l e y Ranch i n 1967.

Water f o r t h e p r o j e c t i s provided by

a s u p p l y w e l l i n t h e s h a l l o w alluvium.

The most r e c e n t i n j e c t i o n r e p o r t s

(December, 1970) i n d i c a t e t h a t a c u m u l a t i v e t o t a l of 2,744,227 b a r r e l s (1.1526 x

lo8

g a l l o n s ) of w a t e r have been i n j e c t e d i n t o t h e Minnelusa

r e s e r v o i r s i n c e 1967.

Average i n j e c t i o n p r e s s u r e s have ranged from

750 t o 2,200 p s i a t t h e w e l l h e a d . Casing Record:

I n j e c t i o n W e l l #A-2, T51N-R69W-30 d c , P l e a s a n t V a l l e y Ranch F i e l d , Heptner U n i t , T o t a l Depth = 8200 f e e t .

Casing S i z e

Wt.

10-314"

(#/ft) 32.75

5-1/2"

17,15.5,14

Depth S e t

Cement

Purpose

177'

100 s a c k s

Surface

8199 '

300 s a c k s

Injection

P o i s o n D r a w F i e l d (5,577,067 b b l s o i l , 6,021,707 MCF g a s ; 1972-79) Teckla "B" U n i t P o i s o n Draw F i e l d i s l o c a t e d i n t h e s o u t h e r n Powder R i v e r Basin. The T e c k l a "B" U n i t of t h e f i e l d i n c l u d e s 1,440 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d which o v e r l i e t h e p r o d u c t i v e Teckla "B" reservoir.

The r e s e r v o i r , a n Upper C r e t a c e o u s , c l a y - f i l l e d

sand

sand, i s

s t r a t i g r a p h i c a l l y s i t u a t e d between t h e younger P i e r r e Shale and t h e o l d e r Teapot Sandstone and covers 4,950 a c r e s w i t h an average n e t pay zone t h i c k n e s s of 21 f e e t .

Average p o r o s i t y of t h e r e s e r v o i r i s

17.3 p e r c e n t . I n 1976, a p i l o t water i n j e c t i o n p r o j e c t began, u t i l i z i n g one i n j e c t i o n w e l l s u p p l i e d w i t h water from t h e Lance and Lewis sands. X-ray d i f f r a c t i o n t e s t s and c o r e a n a l y s e s of Teckla "B"

sand i n d i c a t e d

t h a t 10 p e r c e n t of t h e c l a y content w i t h i n t h e r e s e r v o i r sands was montmorillonite, a s w e l l i n g c l a y t h a t s e v e r e l y reduces r e s e r v o i r p e r m e a b i l i t y when mixed w i t h f r e s h water.

A s of December, 1979, t h e

i n j e c t i o n p r o j e c t had been discontinued.

During t h e period of a c t i v e

i n j e c t i o n , a cumulative volume of 743,981 b a r r e l s (31,247,202 g a l l o n s ) of water were i n j e c t e d i n t o t h e Teckla "B"

reservoir.

Since 1977, s a l t water produced w i t h o i l from t h e Teckla sand r e s e r v o i r has been

i n j e c t e d t o t h e Teckla r e s e r v o i r through a s i n g l e

s a l t water d i s p o s a l w e l l l o c a t e d i n Township 39 North, Range 69 West, S e c t i o n 35.

The depth of t h e w e l l p e r f o r a t i o n s a r e 5,872 f e e t .

Through December, 1979, a cumulative volume of 109,272 b a r r e l s (4,589,424 g a l l o n s ) of b r i n e had been i n j e c t e d .

Casing Record:

S a l t Water Disposal Well #1, T39N-R69W-35 cd, Poison Draw F i e l d , Teckla "B" U n i t , T o t a l Depth = 6026 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

8-5 /8"

24

307 '

225 sacks

5-1/2"

15.5

6026 '

250 s a c k s

P o i s o n S p i d e r F i e l d (3,368,343 b b l s o i l , 65,000 MCF g a s ; 1917-79) Sundance U n i t P o i s o n S p i d e r F i e l d w a s d i s c o v e r e d i n 1917, when a w e l l completed i n t h e upper Sundance Formation began producing a t a r a t e of 5 m i l l i o n c u b i c f e e t of n a t u r a l g a s p e r day.

O i l was d i s c o v e r e d i n 1919, i n t h e

lower Sundance a t a d e p t h of 1,506 f e e t .

The lower sand of t h e Sundance

Formation i s t h e p r i n c i p a l o i l producing sand a t Poison S p i d e r and h a s a n a v e r a g e t h i c k n e s s of 9 1 f e e t . The f i e l d i s s i t u a t e d a t o p a minor dome a l o n g t h e P i n e MountainThe dome i s somewhat e l o n g a t e d i n a northwest-

O i l Mountain f o l d .

s o u t h e a s t d i r e c t i o n and h a s approximately 175 f e e t of c l o s u r e independent of t h e South Casper Creek s t r u c t u r e t o t h e n o r t h w e s t . A p i l o t w a t e r i n j e c t i o n p r o j e c t was s t a r t e d i n March, 1961, u t i l i z i n g one w e l l a t t h e s o u t h e a s t end of t h e f i e l d .

The purpose of t h e

p r o j e c t i s t o supplement t h e r e s e r v o i r producing energy provided by a n a t u r a l water drive.

The a r e a of t h e r e s e r v o i r t h a t i s b e i n g water-

f l o o d e d c o v e r s a b o u t 120 a c r e s and h a s a n a v e r a g e pay zone t h i c k n e s s of a b o u t 30 f e e t .

The a v e r a g e p o r o s i t y and p e r m e a b i l i t y of t h e lower

Sundance r e s e r v o i r a r e 18.2 p e r c e n t and 241 m i l l i d a r c i e s , r e s p e c t i v e l y . Cumulative o i l p r o d u c t i o n t o J a n u a r y 1, 1980, exceeded t h e o r i g i n a l

estimate of o i l i n p l a c e by more t h a n 273,000 b a r r e l s .

Cumulative

w a t e r i n j e c t i o n between 1 9 6 1 and December, 1979, t o t a l e d 2,932,176 8 b a r r e l s (1.2315 x 1 0 g a l l o n s ) of produced Sundance Formation w a t e r . Reported a v e r a g e i n j e c t i o n p r e s s u r e s have y e t t o exceed 0 p s i .

Cody "B" Unit The Cody "B" Unit of Poison Spider F i e l d i s l o c a t e d i n Township 33 North, Range 84 West, Natrona County.

It i s t h e s i t e of an eleven

w e l l n a t u r a l gas i n j e c t i o n p r o j e c t , operated by Union O i l Company of California.

I n j e c t i o n began i n 1974.

A 1 1 of t h e w e l l s a r e completed

i n t h e Upper Cretaceous Cody Shale a t depths between 10,150 and 10,800 f e e t . The average p o r o s i t y of t h e Cody Shale i s 10 t o 12 p e r c e n t , w h i l e t h e average p e r m e a b i l i t y of t h e r e s e r v o i r is l e s s than one m i l l i d a r c y . Nine of t h e i n j e c t i o n w e l l s were a c t i v e during t h e l a s t s i x months of 1979.

Cumulative i n j e c t i o n , s i n c e t h e p r o j e c t s t a r t e d , was

4,915,446 m i l l i o n c u b i c f e e t , a s of December, 1979.

Average i n j e c t i o n

p r e s s u r e s during t h a t period ranged from 4,300 t o 4,850 p s i . Mesaverde "B"

Unit

N a t u r a l g a s i n j e c t i o n t o t h e Mesaverde "B"

reservoir started

i n 1970, through a s i n g l e w e l l l o c a t e d i n S e c t i o n 11, Township 33 North, Range 84 West, Natrona County.

The Mesaverde r e s e r v o i r i s

encountered a t a depth of 9,084 f e e t a t t h a t l o c a t i o n .

A s of December,

1979, 20,388,774 m i l l i o n cubic f e e t of gas had been i n j e c t e d a t average i n j e c t i o n p r e s s u r e s between 1,600 and 2,930 p s i . P r a i r i e Creek F i e l d (958,759 b b l s o i l , 322,682 MCF gas; 1960-79) Lewark Government 6 Unit C o n t i n e n t a l O i l Company i s c u r r e n t l y o p e r a t i n g a s i n g l e w e l l s a l t water d i s p o s a l system a t t h e Lewark Government 6 Unit of P r a i r i e Creek F i e l d .

The d i s p o s a l w e l l i s l o c a t e d i n S e c t i o n 6,

Township 53 North, Range 68 West, Crook County.

Produced b r i n e s

have been i n j e c t e d t o t h e Newcastle Sandstone s i n c e 1976.

Cumulative

i n j e c t i o n d a t a on f i l e a t t h e O i l and Gas Commission i n d i c a t e t h a t a t o t a l of 19,293 b a r r e l s (810,306 g a l l o n s ) of s a l t water were disposed of through w e l l 116 between 1976 and June, 1980.

Prong Creek F i e l d (3,241,084 b b l s o i l ; 1959-79) Prong Creek Unit A one w e l l s a l t water d i s p o s a l system under t h e o p e r a t i o n

of Champlin Petroleum began i n j e c t i n g i n 1972 a t Prong Creek F i e l d . Produced water i s

i n j e c t e d t o t h e Minnelusa Formation a t a

depth of 6,277 f e e t through a w e l l l o c a t e d i n S e c t i o n 6, Township 50 North, Range 67 West, Crook County. have v a r i e d between 540 and 550 p s i .

Average i n j e c t i o n p r e s s u r e s Cumulative i n j e c t i o n through

7 December, 1979, t o t a l e d 1,452,050 b a r r e l s (6.0986 x 1 0 g a l l o n s ) of salt water.

Casing Record:

S a l t Water Disposal Well 111, T50N-R67W-6 bcc, Prong Creek F i e l d , Prong Creek Unit.

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

9-518"

32.3

284 '

200 s a c k s

5-112"

15.5

6367 '

200 s a c k s

Prospect Creek F i e l d (188,413 b b l s o i l ; 1963-79) Crow Mountain Unit O i l was discovered i n t h e T r i a s s i c Crow Mountain sand i n 1963,

a t Prospect Creek F i e l d .

The Crow Mountain Unit covers 1,120 a c r e s

of f e d e r a l , s t a t e , and p r i v a t e land i n Township 45 North, Range 100 West, Hot Springs County, and i s s i t u a t e d on an a n t i c l i n a l s t r u c t u r e along t h e s o u t h e r n margin of t h e Bighorn Basin.

The Crow Mountain

r e s e r v o i r i s composed of redbed sandstones t y p i c a l of t h e Chugwater The r e s e r v o i r depth ranges from 4,850

Group i n t h e Bighorn Basin.

t o 5,160 f e e t on t h e a n t i c l i n e .

The Crow Mountain Unit i s under an

80 a c r e spacing o r d e r by t h e O i l and Gas Conservation Commission. The f i r s t water i n j e c t i o n w e l l s a t Prospect Creek F i e l d went i n t o o p e r a t i o n i n 1972.

By 1978, e i g h t w e l l s were i n j e c t i n g water

from t h e Lakota Sandstone i n t o t h e Crow Mountain Formation.

Average

i n j e c t i o n p r e s s u r e s have ranged from a minimum of 69 p s i t o a maximum of 1,757 p s i a t t h e wellhead.

A s of December, 1979, 4,198,508 b a r r e l s

8 (1.7634 x 10 g a l l o n s ) had been i n j e c t e d s i n c e t h e waterflood began. One of t h e w e l l s was shut-in a t t h e time d a t a were c o l l e c t e d f o r t h i s report

.

Casing Record:

Casing S i z e 4-1/2"

I n j e c t i o n Well Montgomery 111, T45N-R100W-22 dd(cd), Prospect Creek F i e l d , Crow Mountain U n i t , T o t a l Depth = 4863 f e e t . Wt.

(#/ft) 9.5

Grade K-55

Depth S e t

Perforations

4854'

4758-65

'

Cement 100 sacks

Quealy Dome F i e l d (11,823,181 b b l s o i l ; 1934-79) Tensleep U n i t The Tensleep U n i t p a r t i c i p a t i n g area, under t h e o p e r a t i o n of Chevron, U.S.A.,

encompasses 896 a c r e s of f e d e r a l and p r i v a t e l a n d i n

Township 17 North, Ranges 76 and 77 West, Albany County.

The under-

l y i n g Tensleep r e s e r v o i r c o v e r s 260 a c r e s w i t h an a v e r a g e pay zone t h i c k n e s s of about 90 f e e t . g r a y , f i n e - t o medium-grained,

The Tensleep i s composed of w h i t e t o l i g h t cross-bedded,

quartz sandstone with

a v e r a g e p o r o s i t y of 1 5 p e r c e n t and a v e r a g e p e r m e a b i l i t y of 105 m i l l i darcies. The r e s e r v o i r i s p a r t of t h e Quealy dome, one of s e v e r a l s t r u c t u r e s s i t u a t e d a l o n g t h e w e s t margin of t h e Laramie Basin.

The Quealy dome

i s a s m a l l , s h a r p l y f o l d e d dome, e l o n g a t e d i n a n o r t h w e s t - s o u t h e a s t direction.

The e a s t f l a n k of t h e dome d i p s about 20'

toward t h e Laramie

Basin, w h i l e t h e west f l a n k plunges westward u n t i l i t i s almost v e r t i c a l . Quealy dome w a s t h e f i r s t p r o d u c t i v e s t r u c t u r e i n t h e Rocky Mountain a r e a t o be d e f i n e d by seismographic t e s t i n g .

O i l was d i s c o v e r e d a t

Quealy Dome F i e l d i n 1934, when a producing w e l l was completed i n t h e Muddy Sandstone. production.

I n 1947, t h e Tensleep Sandstone came i n t o o i l

The f i e l d was u n i t i z e d i n 1961, and d i v i d e d i n t o t h e

Muddy and Tensleep u n i t s . Water i n j e c t i o n s t a r t e d i n one Tensleep U n i t w e l l i n 1961, u t i l i z i n g w a t e r produced by w e l l s i n t h e Dakota and Tensleep sands.

The

w a t e r f l o o d was expanded t o f i v e w e l l s by 1972, and i n j e c t i o n water was provided by a d d i t i o n a l w e l l s i n t h e Muddy and Lakota s a n d s t o n e s .

As

of December, 1979, a cumulative volume of 19,947,451 b a r r e l s (8.3779 8 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d i n t o t h e Tensleep Sandstone

s i n c e t h e p r o j e c t began.

Average i n j e c t i o n p r e s s u r e s f o r t h e Tensleep

p r o j e c t have ranged from 800 t o 2,450 p s i .

Three of t h e f i v e e x i s t i n g

i n j e c t o r s were s t i l l a c t i v e a s of January 1, 1980. Casing Record:

I n j e c t i o n Well { I l l , T17N-R77W-13 a c a , Quealy Dome F i e l d , Tensleep U n i t , T o t a l Depth = 5875 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

Depth S e t

Cement

13"

40

103 '

118'

75 sacks

7"

24

3238'

3254'

100 s a c k s

Muddy Unit The Muddy Unit of Quealy Dome F i e l d covers t h e same u n i t a r e a a s t h e Tensleep U n i t .

The Muddy r e s e r v o i r i s composed of gray t o brown,

f i n e - t o medium-grained,

porous sandstone w i t h s t r i n g e r s of b l a c k s h a l e .

Water i n j e c t i o n i n t o t h e Muddy Sandstone s t a r t e d i n 1969, w i t h one injection w e l l .

An a d d i t i o n a l w e l l was added t o t h e w a t e r f l o o d i n 1973.

Produced w a t e r from t h e Muddy, Dakota, Lakota, and Tensleep sands was used i n t h e f l o o d . shut-in.

By t h e end of 1978, b o t h of t h e i n j e c t o r s had been

Cumulative i n j e c t i o n d u r i n g t h e p r o j e c t amounted t o 503,827

7 b a r r e l s (2.1160 x 10 g a l l o n s ) of w a t e r .

Average i n j e c t i o n p r e s s u r e s

ranged from 0 t o 2,600 p s i . Casing Record:

I n j e c t i o n Well #4, T17N-R76W-18 cbb, Quealy Dome F i e l d , Muddy U n i t , T o t a l Depth = 3601 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

13"

40

145 '

100 s a c k s

7"

24

3455 '

100 s a c k s

Raven Creek F i e l d (35,628,912 b b l s o i l ; 1956-79) Minnelusa U n i t The Minnelusa o i l r e s e r v o i r a t Raven Creek F i e l d was d i s c o v e r e d i n 1960.

The d i s c o v e r y w e l l was completed i n t h e "B"

Minnelusa Formation a t a d e p t h of 8,338 f e e t .

sand of t h e

The p r o d u c t i v e a r e a of

t h e f i e l d was u n i t i z e d i n 1966, and p u t on an 80 a c r e s p a c i n g o r d e r by t h e O i l and Gas C o n s e r v a t i o n Commission.

The Minnelusa U n i t , a n a r e a

of 4,510 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d , i s l o c a t e d i n Townships 48 and 49 North, Range 69 West, Campbell County. The a v e r a g e t h i c k n e s s of t h e Minnelusa "B" feet.

sand r e s e r v o i r i s 38

Average r e s e r v o i r p o r o s i t y and p e r m e a b i l i t y a r e 1 5 p e r c e n t and

92 m i l l i d a r c i e s , r e s p e c t i v e l y . A secondary o i l r e c o v e r y w a t e r f l o o d p r o j e c t was i n i t i a t e d i n

F e b r u a r y , 1967, w i t h 8 i n j e c t i o n w e l l s a r r a n g e d i n a l i n e d r i v e p a t t e r n a l o n g t h e w e s t edge of t h e f i e l d and completed i n t h e "B" Minnelusa Formation. w e l l system.

sand of t h e

By 1971, t h e p r o j e c t had been expanded t o a 20

F i f t e e n of t h e w e l l s were s t i l l a c t i v e i n December, 1979.

9 I n j e c t i o n r e p o r t s i n d i c a t e t h a t 59,992,609 b a r r e l s (2.5197 x 1 0 g a l l o n s ) of w a t e r from t h e Fox H i l l s Sandstone have been i n j e c t e d The Fox H i l l s a q u i f e r i s found a t a d e p t h of a b o u t

i n t o t h e "B"

sand.

2,240 f e e t .

Average i n j e c t i o n p r e s s u r e s have ranged from a r e p o r t e d

minimum of a

vacuum

t o a maximum p r e s s u r e of 2,650 p s i .

R e c l u s e F i e l d (21,167,909 b b l s o i l , 85,764,150 MCF g a s ; 1967-79) Muddy U n i t R e c l u s e F i e l d i s l o c a t e d i n n o r t h e r n Campbell County, a b o u t s i x m i l e s s o u t h of t h e Wyoming-Montana b o r d e r , i n Townships 56 and 57 N o r t h ,

Ranges 74 and 75 West.

The f i e l d was discovered i n August, 1967, w i t h

t h e completion of producing w e l l s i n t h e "A" and "B" Cretaceous Muddy Sandstone.

sands of t h e Lower

Average depth t o t h e Muddy r e s e r v o i r i n t h e

Recluse F i e l d a r e a i s 7,525 f e e t . The Muddy Sandstone i n t h e v i c i n i t y of Recluse F i e l d i s a complex s e r i e s of interbedded sands, s h a l e s , s i l t s t o n e s , and l o c a l l y t h i n l a y e r s of c o a l o r l i g n i t e .

It i s considered t h e approximate s t r a t i g r a p h i c

e q u i v a l e n t of t h e Newcastle Sandstone of t h e F i d d l e r Creek-Clareton a r e a . The average r e s e r v o i r p o r o s i t y and p e r m e a b i l i t y a r e 16.8 p e r c e n t and 87 m i l l i d a r c i e s ( p e r m e a b i l i t y t o a i r ) , r e s p e c t i v e l y . The p r o d u c t i v e l i m i t s of t h e Muddy r e s e r v o i r , a s t r a t i g r a p h i c hydrocarbon t r a p , a r e d e f i n e d by f a c i e s changes along t h e n o r t h e a s t , northw e s t , and s o u t h e a s t boundaries.

To t h e southwest, t h e boundary i s formed

by a combination of f a c i e s changes and an oil-water c o n t a c t .

The depths

of t h e oil-water c o n t a c t s v a r y a s much a s 183 f e e t i n t h e downdip lobes of t h e southwest boundary.

The r e s e r v o i r rock of t h e Muddy Sandstone

i s d e s c r i b e d a s w h i t e , f i n e - t o medium-grained,

stone with occasional h a i r l i n e shale s t r e a k s .

f r i a b l e , porous sandThe n o r t h h a l f of Recluse

F i e l d was i n i t i a l l y producing under a s o l u t i o n gas d r i v e , w h i l e t h e southern p a r t of t h e a r e a w i l l be produced p r i m a r i l y by a gas cap d r i v e . The Muddy Unit a t Recluse F i e l d covers 8,571.24 a c r e s of f e d e r a l , s t a t e , and p r i v a t e lands.

The f e d e r a l , s t a t e , and patented l e a s e s a r e

d i v i d e d among 30 working i n t e r e s t owners w i t h t h e f e d e r a l government holding l e a s e r i g h t s on about 82 p e r c e n t of t h e productive a r e a . Water i n j e c t i o n t o t h e Muddy began i n 1971, w i t h water provided by supply w e l l s i n t h e Fox H i l l s Sandstone and Lance Formation.

of t h e 28

i n j e c t i o n w e l l s w i t h i n t h e Muddy Unit w a t e r f l o o d , only s i x were a c t i v e

during t h e second h a l f of 1979.

Cumulative i n j e c t i o n t o t h e Muddy

9 r e s e r v o i r , a s of December, 1979, w a s 36,778,813 b a r r e l s (1.5447 x 10 g a l l o n s ) of water.

The maximum average i n j e c t i o n p r e s s u r e during t h e

l i f e of t h e waterflood h a s been 3,500 p s i .

Casing Record:

I n j e c t i o n Well #456, T56N-R74W-8 ab, Recluse F i e l d , Muddy U n i t , T o t a l Depth = 7680 f e e t .

Casing S i z e

Wt.

(#/ft)

8-518"

24

5-1/2"

14,15.5,17

Hole S i z e

Depth S e t

Cement

12-1/4"

317 '

210 sacks

7-7 /8"

7680'

350 sacks

No. 6 Unit

The No. 6 Unit of Recluse F i e l d i s t h e s i t e of a s i n g l e w e l l s a l t water d i s p o s a l system which was p u t i n t o o p e r a t i o n i n 1977, by Eason O i l Company.

The d i s p o s a l w e l l is l o c a t e d i n S e c t i o n 22, Township 56 North,

Range 74 West, Campbell County, and i s completed i n t h e Muddy Sandstone. A s of June, 1979, cumulative

i n j e c t i o n of produced Muddy Sandstone

b r i n e t o t a l e d 8,626 b a r r e l s (362,292 g a l l o n s ) . Red Springs F i e l d (13,286 b b l s o i l ; 1919-79) Frisby-Government Unit An experimental t e r t i a r y o i l recovery p r o j e c t a t t h e FrisbyGovernment Unit of Red Springs F i e l d was i n i t i a t e d i n 1976, by Coronado O i l Company.

The p r o j e c t involved t h e i n j e c t i o n of water and steam

i n t o t h e Tensleep Sandstone through f i v e w e l l s .

A s of December, 1978,

a l l of t h e w e l l s were i n a c t i v e and t h e p r o j e c t had a p p a r e n t l y been abandoned.

Reel F i e l d (5,863,528 b b l s o i l , 25,380 MCF gas; 1962-79) Minnelusa Unit The Minnelusa Unit of Reel F i e l d i n c l u d e s t h e a r e a w i t h i n Sections 27, 28, and 29, Township 49 North, Range 69 West, Campbell County. A secondary o i l recovery waterflood p r o j e c t began a t Reel F i e l d i n 1972, under t h e o p e r a t i o n of S h e l l O i l Company.

Fresh water f o r t h e

p r o j e c t i s provided by a supply w e l l i n t h e Fox H i l l s Sandstone.

Four

of t h e f i v e e x i s t i n g i n j e c t i o n w e l l s were a c t i v e during t h e l a s t s i x months of 1979.

Cumulative i n j e c t i o n between t h e s t a r t of t h e p r o j e c t

8 and t h e end of t h a t period was 9,695,285 b a r r e l s (4.072 x 10 g a l l o n s ) of water.

Average i n j e c t i o n p r e s s u r e s have ranged from a minimum of

1,250 p s i t o a maximum of 3,000 p s i .

Casing Record:

I n j e c t i o n Well 1'143, T49N-R69W-29 d a , Reel F i e l d , Minnelusa U n i t , T o t a l Depth = 8700 f e e t .

Casing S i z e

Wt.

(I'uft)

8-5/8"

24

5-1/2"

15.5,20

Hole S i z e

Depth S e t

Cement

12-1/4"

415 '

300 sacks

7-7 /8"

8698'

325 sacks

Reno F i e l d (8,870,286 b b l s o i l , 176,979 MCF gas; 1965-79) Reno Unit The Reno Unit of Reno F i e l d i s l o c a t e d i n t h e Powder River Basin about f i f t e e n m i l e s n o r t h e a s t of Kaycee, Wyoming.

The u n i t a r e a

encompasses 1,474.72 a c r e s , of which 933.14 a c r e s a r e f e d e r a l l y owned and 541.58 a c r e s a r e f e e l a n d s . The Minnelusa water i n j e c t i o n p r o j e c t i s operated by t h e S h e l l O i l Company and began i n 1968, w i t h i n j e c t i o n i n t o t h r e e w e l l s .

Both f r e s h

water from t h e Fox H i l l s Sandstone and produced water from t h e Minnelusa

Formation a r e used i n t h e w a t e r f l o o d p r o j e c t .

The p r o j e c t was expanded

t o s i x w e l l s i n 1970, and as of J a n u a r y , 1980, o n l y t h r e e of t h e w e l l s were a c t i v e l y i n j e c t i n g . (5.7733 x Formation.

lo8

Between 1968 and 1980, 13,746,007 b a r r e l s

g a l l o n s ) of w a t e r were i n j e c t e d i n t o t h e Minnelusa

A breakdown by w a t e r s o u r c e i s n o t a v a i l a b l e .

The Minnelusa Formation i s a t a d e p t h of approximately 15,000 f e e t i n t h e Reno F i e l d a r e a and h a s a n average t o t a l t h i c k n e s s of 156 f e e t . A w a t e r q u a l i t y a n a l y s i s w a s performed on May 5 , 1967, on Minnelusa w a t e r from w e l l 12-18, l o c a t e d i n T45N-R79W-18

bc.

Results

of t h e a n a l y s i s a r e l i s t e d below: TD S C1

Na SO4 HC03 Ca

Mg pH Hardness

Reynolds Ranch F i e l d (723,488 b b l s o i l ; 1972-79) 1 Sun T. P. S t a t e U n i t The o n l y i n j e c t i o n w e l l a t Reynolds Ranch F i e l d i s a s a l t w a t e r d i s p o s a l w e l l completed i n t h e B u t l e r Sand a t a d e p t h of 5,221 f e e t . The w e l l i s l o c a t e d i n S e c t i o n 1, Township 52 North, Bange 68 West, Crook County.

I n j e c t i o n of produced b r i n e s t a r t e d i n 1973, and as of

7 December, 1978, a cumulative volume of 399,290 b a r r e l s (1.6782 x 1 0 g a l l o n s ) had been i n j e c t e d .

E a s t R i v e r t o n Dome F i e l d (224,646 b b l s o i l , 55,330,889 MCF g a s ; 1965-79) E a s t River t o n U n i t I n 1972, C o n t i n e n t a l O i l Company began i n j e c t i n g b r i n e , produced w i t h o i l from w e l l s around E a s t R i v e r t o n Dome F i e l d , through a s i n g l e s a l t water d i s p o s a l w e l l .

The w e l l i s l o c a t e d i n S e c t i o n 36, Township

1 South, Range 5 E a s t , Fremont County. t h e F r o n t i e r and Nugget f o r m a t i o n s .

Produced b r i n e i s i n j e c t e d i n t o

Between 1972 and June, 1980,

7 1,446,547 b a r r e l s (6.0754 x 1 0 g a l l o n s ) of s a l t w a t e r were i n j e c t e d through- w e l l #3. Robinson Ranch F i e l d (6,939,277 b b l s o i l ; 1958-79) Minnelusa U n i t The Minnelusa U n i t p a r t i c i p a t i n g a r e a c o v e r s 880 a c r e s of Robinson Ranch F i e l d , which i s l o c a t e d about t h r e e m i l e s e a s t of Moorcroft, i n Township 50 North, Range 67 West, Crook County.

The f i e l d was d i s c o v e r e d

i n 1958, and was f e d e r a l l y o p e r a t e d u n t i l 1962.

Low gas t o o i l r a t i o s

and a l i m i t e d w a t e r d r i v e were i n d i c a t e d e a r l y i n t h e l i f e of t h e f i e l d . The Minnelusa Formation i n t h e Robinson Ranch a r e a i s a s a n d s t o n e , i n t e r l a y e r e d w i t h beds of d o l o m i t e and a n h y d r i t e , forming a s t r a t i g r a p h i c t r a p where hydrocarbons have accumulated. of t h e Minnelusa pay zone i s 6,027 f e e t .

T h e a v e r a g e d e p t h t o t h e top

The accumulated o i l i s under-

l a i n by a w a t e r t a b l e which p r o v i d e s t h e major s o u r c e of r e s e r v o i r energy. A f u l l s c a l e gas-water i n j e c t i o n program was approved by t h e Wyoming O i l and Gas Conservation Commission on May 29, 1962.

The

p r o j e c t i s u n u s u a l i n b o t h t e c h n i c a l and mechanical a s p e c t s .

Technically,

t h e p l a n s c a l l e d f o r a two phase i n j e c t i o n of s l u g s of g a s , followed by water, w i t h amounts and time i n t e r v a l s determined by a p i l o t i n j e c t i o n Mechanically, t h e "A" and "B"

study.

sands of t h e Minnelusa Formation

a r e s e p a r a t e d by packers i n t h e i n j e c t i o n w e l l s , p e r m i t t i n g i n j e c t i o n of e i t h e r f l u i d i n e i t h e r zone.

I n theory, t h e gas w i l l lower t h e

v i s c o s i t y of t h e o i l and occupy void space w i t h i n t h e r e s e r v o i r .

The

i n j e c t e d water w i l l tend t o maintain r e s e r v o i r p r e s s u r e and d r i v e t h e oil.

The supply of water f o r t h e p r o j e c t i s provided by production

w e l l s a t Robinson Ranch F i e l d . The p r o d u c t i v e a r e a of t h e r e s e r v o i r i n c l u d e s 462 a c r e s .

S i x of

seven e x i s t i n g i n j e c t i o n w e l l s were a c t i v e during t h e l a s t s i x months of 1979.

A s of December, 1979, a cumulative volume of 18,117,105

8 b a r r e l s (7.6092 x 10 g a l l o n s ) of water had been i n j e c t e d a t average i n j e c t i o n p r e s s u r e s ranging from 50 t o 2,400 p s i . Rock River F i e l d (37,082,926 b b l s o i l , 7,979,278 MCF gas; 1918-79) Muddy Unit Rock River F i e l d i s s i t u a t e d on one of s e v e r a l asymmetrical a n t i c l i n e s along t h e e a s t s l o p e of t h e Medicine Bow Mountains i n Townships 19 and 20 North, Range 78 West, Carbon County.

The e a s t f l a n k of t h e

a n t i c l i n e is s e v e r e l y f a u l t e d and d i p s toward t h e b a s i n a t a n g l e s up t o 70 degrees.

The west f l a n k d i p s back toward t h e mountains a t a n g l e s

of 20 t o 35 degrees.

closure.

The s t r u c t u r e has approximately 1,600 f e e t of

An i n t e r e s t i n g f e a t u r e of Rock River F i e l d i s t h e s t e e p

g r a d i e n t of t h e water t a b l e i n t h e Muddy sand, estimated t o be 750 f e e t i n 3.5 m i l e s .

The f i e l d was discovered i n 1918, w i t h t h e completion of a produci n g w e l l i n t h e Muddy Sandstone a t a depth of 2,581 f e e t .

Production

w e l l s have a l s o been completed i n t h e Dakota and Lakota sands. The Muddy r e s e r v o i r covers 1,098 a c r e s w i t h an average pay zone t h i c k n e s s of 14 t o 20 f e e t .

Average r e s e r v o i r p o r o s i t y and perme-

a b i l i t y a r e 17.8 p e r c e n t and 3.8 m i l l i d a r c i e s , r e s p e c t i v e l y . A w a t e r i n j e c t i o n p r o j e c t t o enhance o i l production from t h e

A t t h a t t i m e , t h e p r o j e c t c o n s i s t e d of one

Muddy sand began i n 1961.

i n j e c t i o n w e l l and s i x producing w e l l s .

A s of January, 1978, cumula-

t i v e i n j e c t i o n t o t h e Muddy through t h e same w e l l was 4,730,666 b a r r e l s 8 (1.9869 x 10 g a l l o n s ) of water from s u r f a c e runoff ponds and from a supply w e l l i n t h e Tensleep Sandstone.

Average i n j e c t i o n p r e s s u r e s

have ranged between 290 and 2,000 p s i d u r i n g t h e period between 1961 and 1978. I n j e c t i o n w e l l #ll (T19N-R78W-11 ba) was d r i l l e d t o a t o t a l depth of 5 , 6 6 1 f e e t .

Seven i n c h c a s i n g was run t o t h e t o t a l depth

and cemented w i t h 250 s a c k s of cement.

The t o p of t h e cement was

determined by temperature survey t o b e a t 2,470 f e e t , o r 586 f e e t above t h e t o p of t h e Muddy Formation.

A Baker b r i d g e plug was s e t a t

3,126 f e e t , t h u s i s o l a t i n g t h e Muddy from t h e o t h e r formations encountered i n t h e h o l e .

I n j e c t i o n t a k e s p l a c e through p e r f o r a t i o n s

i n t h e seven i n c h c a s i n g o p p o s i t e t h e Muddy sand.

Both t h e c a s i n g and

t h e Baker b r i d g e were p r e s s u r e t e s t e d p r i o r t o i n j e c t i o n t o i n s u r e t h a t a l l f l u i d s i n j e c t e d a r e confied t o t h e Muddy r e s e r v o i r and cannot escape t o o t h e r formations.

Cretaceous Unit The Cretaceous Unit of Rock River F i e l d covers an 1,890.18 a c r e a r e a of f e d e r a l , s t a t e , and p r i v a t e land i n Townships 19 and 20 North, Range 78 West, Carbon County.

The Lakota r e s e r v o i r underlying

t h e u n i t , covers about 1,500 a c r e s w i t h an average pay zone t h i c k n e s s estimated t o b e 25 t o 30 f e e t t h i c k .

The average r e s e r v o i r

p o r o s i t y i s 1 6 . 1 p e r c e n t and t h e geometric mean p e r m e a b i l i t y i s 24 millidarcies. Water i n j e c t i o n t o t h e Lakota, Dakota, and Muddy sands i n t h e Cretaceous Unit p a r t i c i p a t i n g a r e a s t a r t e d i n 1964.

Cumulative

i n j e c t i o n through t h e n i n e w e l l s t h a t a r e s t i l l a c t i v e l y i n j e c t i n g 8 was 7,578,336 b a r r e l s (3.1829 x 10 g a l l o n s ) a s of January, 1979. Water used f o r t h e i n j e c t i o n p r o j e c t i s obtaeind from a Tensleep Sandstone supply w e l l and from producing w e l l s i n t h e Cretaceous Unit. A s i n g l e gas i n j e c t i o n w e l l i s a l s o c u r r e n t l y a c t i v e a t t h e

Cretaceous Unit.

The w e l l i s completed i n t h e Lakota r e s e r v o i r and

i s u t i l i z e d f o r p r e s s u r e maintenance w i t h i n t h e r e s e r v o i r .

The most

r e c e n t d a t a a v a i l a b l e on t h e gas i n j e c t i o n p r o j e c t a r e from December, 1967, when t h e two g a s i n j e c t o r s were averaging 674,000 c u b i c f e e t of gas per day t o t h e Lakota sand. Roehrs F i e l d (520,323 b b l s o i l , 12,441 MCF gas; 1966-79) Minnelusa Unit The Minnelusa Unit of Roehrs F i e l d covers 400 a c r e s of f e d e r a l land i n Township 53 North, Range 70 West, Campbell County.

The average

p o r o s i t y and p e r m e a b i l i t y of t h e Minnelusa r e s e r v o i r i n t h e Roehrs F i e l d a r e a a r e 17.3 p e r c e n t and 115 m i l l i d a r c i e s , r e s p e c t i v e l y .

Primary

r e s e r v o i r production mechanisms a r e f l u i d and rock expansion along w i t h p a r t i a l water d r i v e . Water i n j e c t i o n t o t h e Minnelusa r e s e r v o i r began i n 1975, through one w e l l .

During t h e l a s t s i x months of 1979, t h e w e l l was shut-in.

7 Cumulative i n j e c t i o n t o t h a t p o i n t was 1,683,626 b a r r e l s (7.0712 x 10 g a l l o n s ) of f r e s h water provided by a Fox H i l l s Sandstone supply w e l l . Average i n j e c t i o n p r e s s u r e s have ranged from a minimum of 1,175 p s i t o a maximum of 2,950 p s i .

Casing Record:

I n j e c t i o n Well W-3, T53N-R70W-15 ad, Roehrs F i e l d , Minnelusa U n i t , T o t a l Depth = 7532 f e e t .

Casing S i z e

Arnount

Cement

9-5 / 8"

156 '

150 s a c k s

4-1/2"

753'

300 sacks

Rourke Gap F i e l d (1,987,173 b b l s o i l ; 1973-79) Minnelusa Unit Since 1975, t h e Minnelusa Unit a t Rourke Gap F i e l d has been t h e s i t e of a two w e l l water i n j e c t i o n p r o j e c t completed i n t h e Minnelusa

Formation.

The f i e l d i s l o c a t e d i n Township 48 North, Range 7 1 W e s t ,

Campbell County.

The depth t o t h e Minnelusa Formation i n t h e Rourke

Gap a r e a i s about 10,100 f e e t . Cumulative i n j e c t i o n t o t h e Minnelusa r e s e r v o i r was 4,742,104 8 b a r r e l s (1.9917 x 10 g a l l o n s ) of water from the Fox H i l l s Sandstone,

a s of December, 1979.

Average i n j e c t i o n p r e s s u r e s have ranged from

1,100 t o 3,200 p s i . Casing Record:

Casing S i z e

I n j e c t i o n Well #8, T48N-R71W-6 dca, Rourke Gap F i e l d , Minnelusa U n i t , T o t a l Depth = 10,378 f e e t Wt.

(#/ft)

8-5/8"

24

5-1/2"

17,24

Hole S i z e

Depth S e t

Cement

12-1/4"

590'

520 sacks

Surface

7-7 /8"

10377'

575 s a c k s

Injection

Purpose

Rozet F i e l d (17,400,672 b b l s o i l , 8,815,316 MCF gas; 1959-79) Muddy Unit The Muddy Unit of Rozet F i e l d covers an a r e a of 6,638 a c r e s of f e d e r a l , s t a t e , and p r i v a t e land i n Township 50 North, Ranges 69 and 70 West, Campbell County.

A secondary o i l recovery water

i n j e c t i o n p r o j e c t s t a r t e d a t t h e Muddy Unit i n 1968, w i t h t h e i n j e c t i o n of water from t h e Fox H i l l s Sandstone t o t h e Muddy sand r e s e r v o i r through e i g h t w e l l s completed a t depths between 6,500 and 7,200 feet. The Muddy r e s e r v o i r a t Rozet F i e l d i s s t r a t i g r a p h i c a l l y trapped w i t h i n t h e Mowry Shale above and t h e S k u l l Creek Shale below. 1972, t h e waterflood had expanded t o 33 w e l l s .

By

A s of December, 1979,

25 w e l l s were a c t i v e l y i n j e c t i n g and a cumulative volume of 42,018,857 9 b a r r e l s (1.7648 x 10 g a l l o n s ) had been i n j e c t e d during t h e l i f e of the project.

I n j e c t i o n p r e s s u r e s , averaged over each six-month period

a t each a c t i v e w e l l , have ranged from a minimum of 118 p s i t o a maximum of 3,700 p s i .

Casing Record:

I n j e c t i o n W e l l Tr. 1 0 W-1, T50N-R69W-7 Muddy U n i t , T o t a l Depth = 8555 f e e t .

Casing S i z e

(#/ft)

Wt.

a d c , Rozet F i e l d ,

Depth S e t

Cement

8-5/8"

24

308 '

200 s a c k s

4-1/2"

11.6

7375 '

750 s a c k s

F e d e r a l Campbell "A" U n i t A t l a n t i c R i c h f i e l d Company began o p e r a t i n g a s a l t w a t e r d i s p o s a l w e l l a t t h e F e d e r a l Campbell "A" U n i t of Rozet F i e l d i n 1975.

The

w e l l i s completed i n t h e Minnelusa Formation and i s l o c a t e d i n S e c t i o n 11, Township 50 North, Range 70 West, Campbell County.

S i n c e 1975,

b r i n e i n j e c t i o n h a s averaged n e a r l y 10,000 g a l l o n s p e r day.

Cumulative

7 i n j e c t i o n t o J a n u a r y , 1980, was 428,970 b a r r e l s (1.8016 x 1 0 g a l l o n s )

of s a l t w a t e r .

Average i n j e c t i o n p r e s s u r e s have ranged from 700 t o

1,208 p s i . E a s t Rozet F i e l d (2,361,701 b b l s o i l , 217,006 MCF g a s ; 1961-79) Minnelusa U n i t The d i s c o v e r y of o i l a t E a s t Rozet F i e l d was made i n J u n e , 1965, i n t h e Minnelusa Formation.

The Minnelusa U n i t i n c l u d e s 600 a c r e s of

f e d e r a l , s t a t e , and p r i v a t e l a n d i n Township 59 North, Range 69 West, Campbell County.

C u r r e n t l y (December, 1 9 7 9 ) , t h e r e i s one a c t i v e

i n j e c t i o n w e l l w i t h i n t h e Minnelusa U n i t a t E a s t Rozet.

The w e l l i s

completed i n t h e Minnelusa r e s e r v o i r a t a d e p t h of 8,108 f e e t .

Water

f o r i n j e c t i o n i s provided by a s u p p l y w e l l i n t h e Fox H i l l s Sandstone. 7 Cumulative i n j e c t i o n t h r o u g h l 9 7 9 , w a s 1,151,089 b a r r e l s (4.8345 x 1 0 g a l l o n s ) of water.

I n j e c t i o n p r e s s u r e s , averaged f o r each six-month

p e r i o d , have been below 180 p s i s i n c e i n j e c t i o n began.

Casing Record:

I n j e c t i o n W e l l # l , T50N-R69W-20 a a a , E a s t Rozet F i e l d , Minnelusa U n i t , T o t a l Depth = 8206 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5/8"

Hole S i z e

Depth S e t

12-1/4"

167'

24

Cement 145 s a c k s

Muddy U n i t The o i l r e s e r v o i r w i t h i n t h e Muddy Sandstone a t E a s t Rozet F i e l d , was d i s c o v e r e d i n 1961, a t a d e p t h of approximately 8,100 f e e t . r e s e r v o i r i s s t r a t i g r a p h i c a l l y t r a p p e d by o v e r l y i n g s h a l e s .

The

The

p o r o s i t y of samples from t h e Muddy Sandstone, t h a t have a p e r m e a b i l i t y g r e a t e r t h a n one m i l l i d a r c y , r a n g e s from 5.9 t o 25.5 p e r c e n t and averages 15 percent.

The p e r m e a b i l i t y of t h e same samples r a n g e s from

1 . 3 t o 251 m i l l i d a r c i e s , and a v e r a g e s 6 3 m i l l i d a r c i e s . A w a t e r i n j e c t i o n p r o j e c t a t t h e Muddy U n i t was i n i t i a t e d i n 1975. The c u m u l a t i v e volume of w a t e r i n j e c t e d t o t h e Muddy r e s e r v o i r was 230,844 b a r r e l s (9,695,448 g a l l o n s ) as of December, 1979.

Injection

p r e s s u r e s , averaged over six-month p e r i o d s a t t h e two a c t i v e w e l l s , have ranged from 0 t o 2,450 p s i .

Casing Record:

Casing S i z e 8-5/8" 4-1/2"

I n j e c t i o n Well C a r r o l l - D u v a l l # l , T50N-R69W-21 a c c , E a s t Rozet F i e l d , Muddy U n i t , T o t a l Depth = 8301 f e e t . Wt.

(#/ft) 24

9.5,10.5

Cement

Purpose

Hole S i z e

Depth S e t

12-1/4"

202

175 s a c k s

Surface

7-7/8"

6773'

300 s a c k s

Injection

South Rozet F i e l d (4,573,763 b b l s o i l , 114,927 MCF g a s ; 1965-79) North Minnelusa "A" U n i t South Rozet F i e l d was d i s c o v e r e d i n 1965, when a producing w e l l was completed i n t h e Minnelusa Formation a t a d e p t h of about 8,400 f e e t .

The e r r a t i c s t r a t i g r a p h i c n a t u r e of t h e Minnelusa, and t h e d i f f i c u l t y of developing a f i e l d w i t h undefined r e s e r v o i r l i m i t s were pointed out by t h e f i e l d ' s development during 1966.

Of t h e 30 w e l l s completed t h a t

y e a r , 19 were d r y h o l e s and only 11 were producing w e l l s . The Minnelusa Formation i n South Rozet F i e l d c o n s i s t s of a t l e a s t f o u r l e n t i c u l a r sand bodies.

The n o r t h and s o u t h a r e a s of each of t h e

two upper and lower sands a r e i s o l a t e d by a p e r m e a b i l i t y pinchout i n t h e c e n t e r of t h e f i e l d .

The l i m i t s of t h e "A" sand, o r upper sand, i n

t h e n o r t h r e s e r v o i r a r e p r i m a r i l y c o n t r o l l e d by t h e t h i c k n e s s of t h e Opeche Shale.

Rock c h a r a c t e r i s t i c s of t h e n o r t h Minnelusa "A" sand

were determined from a n a l y s i s of e l e c t r i c and s o n i c l o g d a t a , a s w e l l a s core data. percent.

The weighted average p o r o s i t y was determined t o be 17.8

P e r m e a b i l i t y from 36 sample c o r e s averaged 212 m i l l i d a r c i e s .

A water i n j e c t i o n w e l l was completed i n t h e Minnelusa i n 1975, t o

enhance t h e p r o d u c t i v i t y af t h e r e s e r v o i r .

A s of December, 1979,

7 1,590,027 b a r r e l s (6.6781 x 10 g a l l o n s ) of produced Minnelusa water had been i n j e c t e d t o t h e n o r t h "A" sand.

Average i n j e c t i o n p r e s s u r e s

have ranged from 600 t o 2 , 4 3 3 p s i during t h e p r o j e c t . Casing Record:

Casing S i z e 9-518" 5-112"

I n j e c t i o n Well #1, T50N-R69W-30 bb, South Rozet F i e l d , North Minnelusa "A" U n i t , T o t a l Depth = 8505 f e e t . Wt.

(#/ft) 32.3

15.5,17

Hole S i z e

Depth S e t

Cement

Purpose

13-314"

322'

270 sacks

Surface

8-314"

8505'

500 sacks

Injection

M i t c h e l l S t a t e Unit A second water i n j e c t i o n p r o j e c t , a t South Rozet F i e l d , was

e s t a b l i s h e d a t t h e M i t c h e l l S t a t e Unit i n S e c t i o n 35, Township 50 North,

Range 70 West, Campbell County.

Water i s provided by supply w e l l s i n

t h e Fox H i l l s Sandstone and i n j e c t e d i n t o t h e Minnelusa r e s e r v o i r . F u r t h e r d e t a i l s on t h e p r o j e c t were n o t a v a i l a b l e i n t h e O i l and Gas Commission petroleum f i l e s . West Rozet F i e l d (5,220,709 b b l s o i l , 11,385 MCF gas; 1967-79) Minnelusa Unit The Minnelusa Unit a t West Rozet F i e l d covers an a r e a of 1,720 a c r e s of f e d e r a l , s t a t e , and p r i v a t e l a n d s i n Township 50 North, Range 70 West, Campbell County.

The Minnelusa r e s e r v o i r a t West Rozet i s

d e s c r i b e d a s a vuggy, f r a c t u r e d , f i n e - t o medium-grained,

r o s e colored

sand w i t h c h e r t nodules. Water i n j e c t i o n t o t h e Minnelusa Formation a t a depth of 8,700+ f e e t s t a r t e d i n 1971.

By 1978, s i x i n j e c t i o n w e l l s were i n o p e r a t i o n .

Two of t h e w e l l s a r e d u a l l y completed i n t h e Minnelusa r e s e r v o i r . Cumulative i n j e c t i o n , a s of December, 1979, was 24,564,029 b a r r e l s 9 (1.0317 x 10 g a l l o n s ) of produced Minnelusa w a t e r .

Injection pressures,

averaged over each six-month p e r i o d a t each w e l l s i n c e i n j e c t i o n began, have reached a maximum of 2,361 p s i .

Casing Record: Casing S i z e 8-5/8" 4-1/2"

I n j e c t i o n Well W-4, T50N-R70W-27 d a ( c d ) , West Rozet F i e l d , Minnelusa U n i t , T o t a l Depth = 8844 f e e t . Wt.

(#/ft) 24

10.5,13.5

Hole S i z e

Depth S e t

Cement

Purpose

12-1/4"

339'

300 sacks

Surface

7-7/8"

8842 '

400 s a c k s

Injection

Ruben F i e l d (4,309,088 b b l s o i l , 4,874,223 MCF gas; 1969-79) Ruben Unit The Ruben Unit of Ruben F i e l d i n c l u d e s 1,298.5 a c r e s of f e d e r a l l y owned l a n d , s i t u a t e d on a monoclinal s t r u c t u r e i n Township 30 North, Ranges 112 and 113 West, S u b l e t t e County.

The s t r u c t u r a l d i p i n t h e

a r e a i s t o t h e n o r t h e a s t a t 1 . 5 t o 2 degrees.

O i l and gas production

i n t h e a r e a i s from two l e n t i c u l a r lower Almy sands of Eocene age a t depths of 3,300 and 3,600 f e e t . south d i r e c t i o n .

The sands a r e elongated i n a north-

Production l i m i t s of t h e Almy r e s e r v o i r s a r e defined

by t h e pinchout of both sands updip t o t h e west, and by t h e oil-water contact t o the east.

The a r e a encompassed by each of t h e r e s e r v o i r s ,

c a l l e d t h e S t r a y 3 and S t r a y 4 sands, i s approximately 750 a c r e s .

The

average t h i c k n e s s and p o r o s i t y of t h e S t r a y 3 sand a r e 19.8 f e e t and 13.4 p e r c e n t , r e s p e c t i v e l y .

I n t h e S t r a y 4 sand, t h e average t h i c k n e s s

and p o r o s i t y a r e 15.7 f e e t and 13.4 p e r c e n t , r e s p e c t i v e l y . I n j e c t i o n of water from a supply w e l l i n t h e Knight sand t o t h e Almy sands began i n 1970. Petroleum Corporation.

The waterflood p r o j e c t i s operated by Belco

S i x of t h e n i n e e x i s t i n g i n j e c t i o n w e l l s a t t h e

Ruben Unit a r e d u a l l y completed i n t h e S t r a y 3 and 4 sands.

A s of

December, 1979, t h e cumulative volume of water i n j e c t e d t o t h e Almy was 8 6,290,429 b a r r e l s (2.642 x 10 g a l l o n s ) .

have ranged from 500 t o 2,750 p s i .

Average i n j e c t i o n p r e s s u r e s

Seven of t h e w e l l s were a c t i v e

during t h e l a s t s i x months of 1979.

Casing Record:

I n j e c t i o n Well #3, T30N-R112W-19 cad, Ruben F i e l d , Ruben U n i t , T o t a l Depth = 3640 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5/8"

24

5-1/2"

14,15.5

Hole S i z e 12-1/4" 7-7 /8"

Depth S e t

228 ' 3640

Cement 150 sacks 200 sacks

Ryckman Creek F i e l d (3,782,786 b b l s o i l , 1,234,288 MCF gas; 1976-79) Ryckman Creek Unit Since 1977, t h e Ryckman Creek Unit has been t h e s i t e of a s i n g l e w e l l s a l t water d i s p o s a l system and a f i v e w e l l gas i n j e c t i o n p r o j e c t . The u n i t i s l o c a t e d i n Township 17 North, Ranges 118 and 119 West, Uinta County, and i n c l u d e s 1,235.83 a c r e s of f e d e r a l and p r i v a t e land. The purpose of t h e gas i n j e c t i o n p r o j e c t i s t o enhance o i l and gas production from t h e Nugget Sandstone.

The Nugget r e s e r v o i r i s

encountered a t depths between 7,200 and 7,600 f e e t i n t h e Ryckman Creek a r e a .

A l l f i v e i n j e c t i o n w e l l s were a c t i v e during t h e l a s t s i x

months of 1979.

Cumulative i n j e c t i o n through December, 1975, was

5,754,420 MCF of n a t u r a l gas.

I n j e c t i o n p r e s s u r e s , averaged over each

six-month period between 1977 and December, 1979, ranged between 1,345 and 2,358 p s i . The s a l t water d i s p o s a l w e l l i s l o c a t e d i n S e c t i o n 25, Township 17 North, Range 119 West. depth of 7,581 f e e t .

I n j e c t i o n i s t o t h e Nugget Formation a t a

Cumulative i n j e c t i o n t o t h e Nugget, through June,

7 1980, was 862,323 b a r r e l s (3.6217 x 1 0 g a l l o n s ) of produced b r i n e . Average i n j e c t i o n p r e s s u r e s have ranged from 50 t o 280 p s i .

Sage Creek F i e l d (9,216,952 b b l s o i l ; 1948-79) Tensleep Unit Sage Creek F i e l d i s s i t u a t e d on t h e asymmetrical Frannie a n t i c l i n e i n Township 57 North, Range 97 West, Big Horn and Park c o u n t i e s . Contours on t h e top of t h e F r o n t i e r Formation i n d i c a t e t h a t Sage Creek F i e l d i s a second dome on t h e a n t i c l i n a l s t r u c t u r e , w i t h l e s s than 200 f e e t of c l o s u r e .

O i l was discovered a t Sage Creek i n 1948, w i t h t h e

completion of a p r o d u c t i v e w e l l i n t h e Madison Limestone.

The d i s c o v e r y

of Tensleep o i l d i d n o t occur u n t i l 1953. S h o r t l y t h e r e a f t e r , t h e Tensleep U n i t was e s t a b l i s h e d i n o r d e r t o more e f f i c i e n t l y e x p l o i t t h e r e s o u r c e s u n d e r l y i n g t h e a r e a .

Sohio

Petroleum Company became t h e o p e r a t o r of t h e Tensleep U n i t , a 737.6 a c r e a r e a of f e d e r a l and p r i v a t e l a n d .

Water i n j e c t i o n through one w e l l

began a t t h e Tensleep U n i t of Sage Creek F i e l d i n 1971. was added i n 1976. producing w e l l s .

Another w e l l

Water f o r t h e p r o j e c t i s o b t a i n e d from Tensleep Cumulative i n j e c t i o n through December, 1979, was

8 12,869,573 b a r r e l s (5.4052 x 1 0 g a l l o n s ) a t average i n j e c t i o n p r e s s u r e s between 400 and 1,200 p s i . Sage S p r i n g Creek F i e l d (10,788,558 b b l s o i l , 3,342,399 MCF g a s ; 1949-79) Dakota "A" U n i t Sage S p r i n g Creek F i e l d i s l o c a t e d i n Townships 36 and 37 North, Range 77 West, Natrona County.

Seismic s t u d i e s have o u t l i n e d t h e under-

l y i n g s t r u c t u r e of t h e f i e l d a s a south-plunging a n t i c l i n a l nose.

The

Sage S p r i n g Creek d i s c o v e r y w e l l was completed i n t h e Dakota sand i n 1949. The Dakota "A" U n i t c o v e r s a 1,845.79 a c r e a r e a of f e d e r a l (1,346.46 a c r e s ) , s t a t e (100 a c r e s ) , and p r i v a t e (399.33 a c r e s ) l a n d and was e s t a b l i s h e d d u r i n g t h e 1950's.

The i n j e c t i o n of w a t e r t o

enhance t h e p r o d u c t i v i t y of o i l from t h e Dakota sand was s t a r t e d i n 1972, through f o u r w e l l s .

The f i f t h w e l l w a s added i n 1975.

A l l of

t h e w e l l s a r e completed i n t h e Dakota r e s e r v o i r a t d e p t h s between 7,300 and 7,500 f e e t .

Water f o r t h e p r o j e c t i s o b t a i n e d from supply w e l l s

i n t h e Parkman Sandstone.

To January, 1980, cumulative i n j e c t i o n amounted

8 t o 7,501,685 b a r r e l s (3.1507 x 10 g a l l o n s ) .

A l l f i v e w e l l s were a c t i v e

d u r i n g t h e l a s t h a l f of 1979. Casing Record :

I n j e c t i o n Well # ~ - l g , T37N-R7 7W-29 cdb , Sage Spring Creek F i e l d , Dakota "A" U n i t , T o t a l Depth = 7556 f e e t .

Casing S i z e

Wt.

10-3 / 4" 4-1/2"

(#/ft)

Hole S i z e

Depth S e t

13-3/4"

333'

200 sacks

7-7/8"

7555'

225 sacks

40.5 9.5,10.5,11.6

Cement

S a l t Creek F i e l d (575,972,623 b b l s o i l , 711,185,987 MCF gas; 1889-1979) S a l t Creek o i l and gas f i e l d i s l o c a t e d i n Townships 39 and 40 North, Ranges 78 and 79 West, Natrona County, and i s one of t h e l a r g e s t o i l f i e l d s i n t h e e n t i r e Rocky Mountain region. O i l s e e p s were r e p o r t e d i n t h e S a l t Creek F i e l d a r e a b e f o r e 1880,

i n t h e accounts of t h e e a r l y s e t t l e r s of e a s t - c e n t r a l Wyoming.

The

f i r s t w e l l was d r i l l e d t o t h e Shannon Sandstone on t h e n o r t h end of t h e S a l t Creek dome i n 1889.

The Shannon r e s e r v o i r covers about 160 a c r e s

a t a depth of 700 t o 1,000 f e e t .

The Shannon Formation crops o u t l e s s

than two m i l e s s o u t h of t h e o r i g i n a l w e l l and forms t h e escarpment around t h e S a l t Creek dome. S e v e r a l minor o i l f i n d s were made i n Upper Cretaceous s h a l e s i n 1906, b u t i t wasn't u n t i l 1908, t h a t t h e S a l t Creek dome a t t r a c t e d t h e a t t e n t i o n of t h e o i l producing companies.

During t h a t y e a r , a w e l l

d r i l l e d t o t h e f i r s t Wall Creek sand came i n t o production a t a r a t e of 200 b a r r e l s of o i l per day.

During t h e subsequent 46 y e a r s , t h e

following formations came i n t o production a t S a l t Creek F i e l d :

second

Wall Creek sand, 1917; Lakota Sandstone, 1921; t h i r d Wall Creek sand,

1924; second Sundance sand and Lakota s h a l e , 1925; t h i r d Sundance sand, 1926; Morrison, 1929; Tensleep Sandstone, 1930; f i r s t Sundance s a n d , 1953; and F i s h t o o t h s h a l e , 1954.

By December, 1979, t h e r e were e i g h t a c t i v e water i n j e c t i o n operat i o n s a t S a l t Creek F i e l d .

The L i g h t O i l U n i t

-

f i r s t , second, and

t h i r d W a l l Creek p r o j e c t s a r e o p e r a t e d by Amoco P r o d u c t i o n Company. T e r r a Resources, I n c . , o p e r a t e s t h e S t a l e y Government and S a l t Creek South U n i t s .

A t E a s t S a l t Creek F i e l d , A t l a n t i c R i c h f i e l d Company

o p e r a t e s w a t e r i n j e c t i o n p r o j e c t s i n t h e Second Wall Creek and Tensleep units,

and. Kewanee O i l Company i s t h e o p e r a t o r of t h e w a t e r f l o o d a t

t h e Second Wall Creek U n i t of West S a l t Creek F i e l d .

Staley Unit The S t a l e y U n i t of S a l t Creek F i e l d i s l o c a t e d i n Townships 39 and 40 North, Range 78 West, Natrona County.

Water i n j e c t i o n t o t h e second

W a l l Creek sand s t a r t e d i n 1963, and by 1969, had expanded t o a f u l l

s c a l e , t e n w e l l waterflood. t i o n f o r water.

The Madison Limestone i s t h e s o u r c e forma-

A l l of t h e i n j e c t o r s a r e completed a t d e p t h s between

1,900 and 2,150 f e e t . Cumulative i n j e c t i o n , as of December, 1979, w a s 61,446,728 b a r r e l s 9 (2.5808 x 10 g a l l o n s ) of Madison w a t e r a t a v e r a g e i n j e c t i o n p r e s s u r e s r a n g i n g from 400 t o 1 , 3 7 5 p s i .

Casing Record:

I n j e c t i o n W e l l #37, T40N-R78W-31 c c d , S a l t Creek F i e l d , S t a l e y U n i t , T o t a l Depth = 2,123 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

8-5/8"

24

12-1/4"

32'

10 s a c k s

4-1/2"

9.5

7-7/8"

2116'

150 s a c k s

-

Light O i l Unit

F i r s t Wall Creek Sand

The Light O i l Unit a t S a l t Creek F i e l d was e s t a b l i s h e d i n September, 1939, and covers 15,338 a c r e s i n Townships 39 and 40 North, Ranges 78 and 79 West, Natrona County.

The water i n j e c t i o n

p r o j e c t i n t h e L i g h t O i l Unit f i r s t Wall Creek sand s t a r t e d i n January, 1955.

The i n j e c t i o n w e l l c o n f i g u r a t i o n was a twin five-spot p a t t e r n .

Expansion t o a f u l l s c a l e waterflood took p l a c e between 1957 and 1961, and by 1979, 262 w e l l s had been completed i n t h e f i r s t Wall Creek sand.

Within 6 months of t h e s t a r t of t h e p i l o t p r o j e c t o i l produc-

t i o n i n c r e a s e d by more than 500 b a r r e l s per day. The f i r s t Wall Creek r e s e r v o i r i n c l u d e s 4,035 a c r e s w i t h an average pay zone t h i c k n e s s of 80 f e e t .

Core a n a l y s e s i n d i c a t e an

average p o r o s i t y and p e r m e a b i l i t y of 16 percent and 80 m i l l i d a r c i e s , respectively. Limestone.

The water source f o r t h e i n j e c t i o n p r o j e c t i s t h e Madison

A water supply w e l l , capable of providing 80,000 g a l l o n s

p e r day, was d r i l l e d f o r t h e p r o j e c t . The cumulative volume of Madison water i n j e c t e d s i n c e t h e p i l o t g a l l o n s ) a s of p r o j e c t began was 798,729,371 b a r r e l s (3.3547 x 1 0 ' ~ December, 1979.

Reported average i n j e c t i o n p r e s s u r e s during t h a t

period d i d n o t exceed 500 p s i .

During t h e l a s t s i x months of 1979,

1 7 1 of t h e w e l l s were a c t i v e l y i n j e c t i n g .

Casing Record:

I n j e c t i o n Well #33, T40N-R79W-13 c c , S a l t Creek F i e l d , Light O i l Unit - F i r s t Wall Creek Sand, T o t a l Depth = 1710 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

13-3/8"

45

113'

10 sacks

10-3/4t'

45

1219 '

-

8-518"

20

1459 '

210 sacks

Light O i l Unit

-

Second Wall Creek Sand

The second p i l o t w a t e r i n j e c t i o n p r o j e c t a t t h e L i g h t O i l Unit s t a r t e d i n J u n e , 1960, w i t h i n j e c t i o n t o t h e second Wall Creek sand. It was expanded t o a f u l l s c a l e f l o o d i n November, 1961.

The second Wall Creek r e s e r v o i r c o v e r s more t h a n 15,000 a c r e s a t S a l t Creek F i e l d , w i t h a n a v e r a g e pay t h i c k n e s s of 59 f e e t and a v e r a g e p o r o s i t y and p e r m e a b i l i t y , from c o r e a n a l y s e s , of 1 8 p e r c e n t and 100 millidarcies, respectively.

The o r i g i n a l producing mechanism of t h e Water i n j e c t i o n i s g e n e r a l l y updip

r e s e r v o i r was s o l u t i o n g a s d r i v e .

from t h e r e s e r v o i r and supplements n a t u r a l g r a v i t y d r a i n a g e . Four w a t e r s u p p l y w e l l s completed i n the Madison Limestone p r o v i d e water f o r the i n j e c t i o n project.

The combined open f l o w from t h e w e l l s

i s over 250,000 b a r r e l s 0 . 0 5 x 1 0

7

g a l l o n s ) p e r day.

Water from t h e

Madison comes o u t of t h e s u p p l y w e l l s a t 1 8 4 ' ~ . A chemical i s added t o t h e water, p r i o r t o i n j e c t i o n , t o c o n t r o l s u l f a t e reducing b a c t e r i a . Produced w a t e r from t h e Tensleep Sandstone i s a l s o i n j e c t e d . A s of December, 1979, t h e r e were 406 i n j e c t i o n w e l l s completed i n

t h e second W a l l Creek sand of t h e L i g h t O i l U n i t . were i n j e c t i n g d u r i n g t h e l a s t s i x months of 1979. t h e w e l l s a r e t e m p o r a r i l y o r permanently s h u t - i n . through 1979, was 1,392,890,952 b a r r e l s (5.8501 x

Of t h a t t o t a l , 346 The remainder of Cumulative i n j e c t i o n

lo1'

g a l l o n s ) of

water. Casing Record:

I n j e c t i o n W e l l #9, T40N-R79W-23 bb, S a l t Creek F i e l d , L i g h t O i l U n i t - Second Wall Creek Sand.

Casing S i z e 13" 8-5 / 8" 5-1/2" (liner)

Wt.

( m t )

Depth S e t

Cement

45

87'

10 sacks

28

1447 '

60 s a c k s

Light O i l Unit

-

T h i r d Wall Creek Sand

Water i n j e c t i o n i n t o t h e t h i r d W a l l Creek sand a t t h e L i g h t O i l U n i t of S a l t Creek F i e l d s t a r t e d i n 1969. Creek r e s e r v o i r i s about 1,800 f e e t .

The d e p t h t o t h e t h i r d Wall

Water f o r t h e i n j e c t i o n p r o j e c t

i s o b t a i n e d from s u p p l y w e l l s i n t h e Madison Limestone.

Only t h r e e of

t h e n i n e e x i s t i n g i n j e c t o r s were a c t i v e d u r i n g t h e second h a l f of 1979. The o t h e r w e l l s were t e m p o r a r i l y s h u t - i n .

Cumulative i n j e c t i o n a s of

8 December, 1979, was 6,719,260 b a r r e l s (2.8221 x 10 g a l l o n s ) of w a t e r .

Casing Record:

I n j e c t i o n Well #22, T40N-R79W-34 dd, S a l t Creek F i e l d , L i g h t O i l U n i t - T h i r d Wall Creek Sand, T o t a l Depth = 1874 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

12-1/2"

45

49'

10 s a c k s

8- 1/ 4"

28

1522'

40 s a c k s

6-5/8"

20

1832'

-

South U n i t The second Wall Creek r e s e r v o i r of t h e South U n i t a t S a l t Creek F i e l d c o v e r s a 6,110 a c r e a r e a w i t h a n a v e r a g e pay zone t h i c k n e s s of 25 f e e t .

The primary producing mechanisms of t h e r e s e r v o i r were s o l u -

t i o n g a s d r i v e and g r a v i t y d r a i n a g e .

Average r e s e r v o i r p o r o s i t y and

p e r m e a b i l i t y a r e 16 p e r c e n t and 4 m i l l i d a r c i e s , r e s p e c t i v e l y , a t w e l l #12-159

(T39N-R79W-12

ab).

The second Wall Creek sand i s found a t a

d e p t h of 1 , 9 5 0 t o 2,600 f e e t i n t h e South U n i t a r e a . The South U n i t i s l o c a t e d i n Township 39 North, Ranges 78 and 79 West, Natrona County.

The second Wall Creek sand w a t e r i n j e c t i o n

p r o j e c t a t South U n i t began i n August, 1962, w i t h f ~ u wr e l l s .

Water

f o r t h e p r o j e c t was o b t a i n e d from s u p p l y w e l l # 1 d r i l l e d t o t h e Madison

Limestone.

The o r i g i n a l i n j e c t i o n w e l l s were l o c a t e d along t h e n o r t h

and s o u t h u n i t boundaries t o prevent o i l from migrating a c r o s s them. During t h e l a s t 1 8 y e a r s , t h e p r o j e c t has been expanded t o i n c l u d e 157 i n j e c t i o n w e l l s , of which 116 were a c t i v e l y i n j e c t i n g during t h e second h a l f of 1979.

The r e s t were e i t h e r shut-in f o r t h a t

p e r i o d , o r were p r e v i o u s l y abandoned.

Cumulative i n j e c t i o n through

9 a l l w e l l s a s of December, 1979, was 497,193,754 b a r r e l s (2.0882 x 10 g a l l o n s ) of water from t h e Madison Limestone.

Average i n j e c t i o n

p r e s s u r e s during t h e p r o j e c t ' s l i f e t i m e have ranged from 17 t o 3,040 p s i . S a l t Creek Unit Amoco Production Company s t a r t e d a f o u r w e l l t e r t i a r y o i l recovery i n j e c t i o n p r o j e c t i n 1972, a t S a l t Creek F i e l d .

The p r o j e c t involves

t h e i n j e c t i o n of a w a t e r / m i c e l l a r s o l u t i o n i n t o t h e Wall Creek Sandstone.

F u r t h e r d e t a i l s were n o t a v a i l a b l e from f i l e s a t t h e O i l and

Gas Commission.

East S a l t Creek F i e l d (11,721,277 b b l s o i l , 790,130 MCF gas; 1951-79) Second Wall Creek Unit The discovery w e l l a t East S a l t Creek F i e l d was a d u a l completion w e l l i n t h e second Wall Creek and Lakota sands, and began producing i n December, 1951.

The second Wall Creek r e s e r v o i r covers 440 a c r e s w i t h

an average pay zone t h i c k n e s s of 28 f e e t .

The average p o r o s i t y and

p e r m e a b i l i t y of t h e r e s e r v o i r a r e 19 p e r c e n t and 26 m i l l i d a r c i e s , respectively. The p a r t i c i p a t i n g a r e a of t h e Second Wall Creek Unit o v e r l i e s t h e r e s e r v o i r i n S e c t i o n s 4 , 9 , 10, and 22, Township 40 North, Range 78

West, Natrona County.

L a t e i n 1966, t h e E a s t S a l t Creek w a t e r f l o o d

agreement was approved. began i n May, 1967.

Water i n j e c t i o n t o t h e second Wall Creek sand

By 1975, f i v e w e l l s were i n j e c t i n g w a t e r from

Tensleep Sandstone p r o d u c t i o n w e l l s .

A s of December, 1979, o n l y t h r e e

w e l l s remained on a c t i v e s t a t u s and c u m u l a t i v e i n j e c t i o n t o t a l e d 8 14,497,601 b a r r e l s (6.09 x 1 0 g a l l o n s ) of w a t e r s i n c e t h e w a t e r f l o o d

started.

Average i n j e c t i o n p r e s s u r e s have ranged between 200 and 1,676

psi. Lakota U n i t The s t a r t of t h e w a t e r i n j e c t i o n p r o j e c t a t t h e Lakota U n i t of E a s t S a l t Creek F i e l d a l s o o c c u r r e d i n May, 1967.

The s o l e Lakota

Sandstone i n j e c t o r was s h u t - i n a few y e a r s l a t e r and h a s n o t been utilized since.

7 A t o t a l of 538,425 b a r r e l s (2.2613 x 1 0 g a l l o n s ) of

produced Tensleep w a t e r was i n j e c t e d w h i l e t h e w e l l w a s a c t i v e .

Average

i n j e c t i o n p r e s s u r e s ranged from 400 t o 1 , 7 5 0 p s i .

Tensleep U n i t The f i r s t o i l p r o d u c t i o n from t h e Tensleep Sandstone a t E a s t S a l t Creek F i e l d t o o k p l a c e i n October, 1956.

Water i n j e c t i o n t o enhance

p r o d u c t i o n from t h e Tensleep r e s e r v o i r s t a r t e d i n 1970, through one well.

The Tensleep U n i t i s l o c a t e d i n Township 40 North, Bange 78 West,

Natrona County. i n the unit area.

The r e s e r v o i r i s encountered a t a d e p t h of 7,472 f e e t Cumulative i n j e c t i o n d u r i n g t h e p a s t t e n y e a r s

8 t o t a l e d 4,443,722 b a r r e l s (1.8664 x 1 0 g a l l o n s ) of produced w a t e r from

t h e Tensleep Sandstone.

I n j e c t i o n p r e s s u r e s averaged over each s i x

month p e r i o d have ranged between 353 and 1,450 p s i .

West S a l t Creek F i e l d (1,746,305 b b l s o i l , 4,003 MCF g a s ; 1917-79) West U n i t West S a l t Creek F i e l d i s l o c a t e d i n Township 40 North, Range 79

West, Natrona County, j u s t t o t h e west of t h e s t r u c t u r a l a x i s of t h e Bothwell s y n c l i n e .

The f i e l d was d i s c o v e r e d as a r e s u l t of s t e p - o u t

d r i l l i n g a t S a l t Creek F i e l d .

O i l was found i n t h e N i o b r a r a - C a r l i l e

s a n d s a t a b o u t 2,200 f e e t , t h e second Wall Creek sand a t a b o u t 2,600 f e e t , and t h e F i s h t o o t h sand from 742 t o 790 f e e t . The i n j e c t i o n of w a t e r from t h e Madison Limestone t o t h e second Wall Creek r e s e r v o i r s t a r t e d i n J u l y , 1964, through t e n w e l l s a r r a n g e d

p e r i p h e r a l l y around t h e West U n i t .

The Madison w a t e r , which c o n t a i n e d

hydrogen s u l f i d e , was c h e m i c a l l y t r e a t e d p r i o r t o i n j e c t i o n . w a t e r f l o o d p r o j e c t was s h u t - i n d u r i n g 1979.

The

Cumulative i n j e c t i o n a t

8 t h e t i m e t h e w e l l s were s h u t - i n was 8,776,474 b a r r e l s (3.6861 x 1 0

gallons).

Average i n j e c t i o n p r e s s u r e s ranged from 205 t o 1 , 3 1 0 p s i .

Semlek F i e l d (3,251,630 b b l s o i l , 31,792 MCF g a s ; 1962-79) B-2 M e l l o t t U n i t I n 1970, Texaco, I n c . s t a r t e d a s a l t w a t e r d i s p o s a l p r o j e c t a t Semlek F i e l d i n t h e B-2 M e l l o t t U n i t , l o c a t e d i n Township 52 N o r t h , Range 68 West, Crook County.

Produced b r i n e i s

Dakota-Lakota s a n d s a t a d e p t h of 5,449 f e e t .

injected into the A s of J u n e , 1980,

8 12,802,139 b a r r e l s (5.3769 x 1 0 g a l l o n s ) of s a l t w a t e r had been injected.

Casing Record:

S a l t Water D i s p o s a l W e l l 112, T52N-R68W-27, Semlek F i e l d , B-2 M e l l o t t U n i t , T o t a l Depth = 7024 f e e t .

Casing S i z e 10-3/4" 7"

Wt.

(Wt)

Depth S e t

40.5 20,23,26,29

Cement

302 '

190 s a c k s

6998'

725 s a c k s

West Semlek F i e l d (4,814,625 b b l s o i l ; 1962-79)

West U n i t A p a i r of w a t e r i n j e c t i o n p r o j e c t s a r e c u r r e n t l y (June, 1980)

a c t i v e a t t h e West U n i t of West Semlek F i e l d . secondary r e c o v e r y w a t e r f l o o d of t h e "A"

The f i r s t p r o j e c t , a

sand of t h e Minnelusa Forma-

t i o n , s t a r t e d i n 1972, and i s o p e r a t e d by T e r r a Resources, I n c . Cumulative i n j e c t i o n d a t a and a v e r a g e i n j e c t i o n p r e s s u r e s were n o t a v a i l a b l e a t t h e t i m e of t h i s w r i t i n g . The second i n j e c t i o n p r o j e c t i s a s i n g l e w e l l s a l t w a t e r d i s p o s a l system, completed i n t h e "C"

sand of t h e Minnelusa Formation.

Disposal

of produced Minnelusa b r i n e s t a r t e d i n 1978, through a w e l l l o c a t e d i n S e c t i o n 28, Township 52 N o r t h , Range 68 West, Crook County.

Cumulative

7 i n j e c t i o n through J u n e , 1980, was 508,949 b a r r e l s (2.1375 x 1 0 g a l l o n s )

of b r i n e .

I n j e c t i o n p r e s s u r e s averaged over each s i x month p e r i o d ranged

between a minimum of 1,250 p s i and a maximum of 2,734 p s i .

The d e p t h

t o t h e Minnelusa Formation i s 7,420 f e e t a t t h e w e l l s i t e . Casing Record:

S a l t Water D i s p o s a l Well #8, T52N-R68W-28 bd, West Semlek F i e l d , West U n i t , T o t a l Depth = 7575 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

5-112"

17

45' ,841'

565 s a c k s

5-112''

15.5

6705'

460 s a c k s

Sharp F i e l d (218,428 b b l s o i l , 11,150 MCF g a s ; 1975-79) Minnelusa U n i t The Minnelusa U n i t of Sharp F i e l d i s l o c a t e d i n Township 49 N o r t h , Range 7 1 West, Campbell County.

The f i e l d was d i s c o v e r e d i n 1975, when

a producing w e l l was completed i n t h e Minnelusa Formation.

The Minnelusa

r e s e r v o i r i s found a t a d e p t h of a b o u t 10,100 f e e t i n t h e Sharp F i e l d a r e a and h a s a n a v e r a g e p o r o s i t y of 15.5 p e r c e n t . Anderson O i l Company began water i n j e c t i o n t o t h e Minnelusa r e s e r v o i r i n 1977, w i t h w a t e r o b t a i n e d from t h e Fox H i l l s Sandstone. I n 1979, a second w e l l was added t o t h e w a t e r f l o o d .

Cumulative i n j e c t i o n

7 through December of t h a t y e a r was 501,467 b a r r e l s (2.1061 x 1 0 g a l l o n s ) . Average i n j e c t i o n p r e s s u r e s have ranged from 1 , 3 0 0 t o 2,900 p s i . Casing Record: Casing S i z e 8-518'' 5-112''

I n j e c t i o n Well Wolf e 111, T49N-R71W-29 b a ( b c ) , Sharp F i e l d , Minnelusa U n i t , T o t a l Depth = 10,390 f e e t . Wt.

(#/ft) 24

15.5,17

Hole S i z e 12-114"

Depth S e t

Cement

Purpose

714'

460 s a c k s

Surface

10,269'

325 s a c k s

Injection

Northwest Sheldon Dome F i e l d (3,352,618 b b l s o i l , 1,753 MCF g a s ; 1954-79) T r i b a l "A" U n i t The T r i b a l "A" U n i t of Northwest Sheldon Dome F i e l d i s t h e s i t e of a two w e l l s a l t w a t e r d i s p o s a l system s t a r t e d i n 1969, and o p e r a t e d by S k e l l y O i l Company.

Produced b r i n e , from w e l l s completed i n t h e

T r i a s s i c Crow Mountain Sandstone, i s reservoir.

i n j e c t e d t o t h e Crow Mountain

Cumulative i n j e c t i o n and p r e s s u r e d a t a f o r t h e d i s p o s a l

p r o j e c t were n o t a v a i l a b l e a t t h e t i m e of t h i s w r i t i n g .

Shoshone F i e l d (2,321,820 b b l s o i l ; 1929-79) Crickett Unit Shoshone F i e l d i s l o c a t e d i n Township 53 North, Range 1 0 1 West, P a r k County, and i s t h e s i t e of a s i n g l e w e l l s a l t w a t e r d i s p o s a l system completed i n t h e Permian Phosphoria Formation a t a d e p t h of 4,378 f e e t .

I n j e c t i o n of produced b r i n e i n t o t h e Phosphoria s t a r t e d

i n 1972, and i s o p e r a t e d by Husky O i l Company.

Cumulative i n j e c t i o n

7 as of J u n e , 1979, was 936,161 b a r r e l s (3.9318 x 1 0 g a l l o n s ) of s a l t water.

Average i n j e c t i o n p r e s s u r e s have ranged from 1,444 t o 2,302

p s i d u r i n g t h e p e r i o d from 1972 t o J u n e , 1979. Casing Record:

S a l t Water D i s p o s a l W e l l #2, T53N-R101W-28, Shoshone F i e l d , C r i c k e t t U n i t , T o t a l Depth = 4378 f e e t .

Casing S i z e 7"

Wt.

(#/ft) 20,23

Depth S e t

Cement

4378'

101 sacks

S i l v e r T i p F i e l d (4,504,523 b b l s o i l , 26,765,455 MCF g a s ; 1948-79) S i l v e r Tip Unit S i l v e r T i p F i e l d was d i s c o v e r e d i n A p r i l , 1948, when a producing w e l l was completed i n t h e Phosphoria Formation.

It began producing o i l

and gas a t a r a t e of 1,200 b a r r e l s and 4.2 m i l l i o n cubic f e e t , r e s p e c t i v e l y , per day.

Production of o i l from t h e F r o n t i e r Formation

and Tensleep Sandstone began d u r i n g t h e same month. The S i l v e r Tip Unit was approved i n November, 1953, w i t h Texaco, Inc., a s the u n i t operator.

A gas i n j e c t i o n and a water i n j e c t i o n

p r o j e c t have operated i n t h e f i e l d s i n c e u n i t i z a t i o n .

A gas i n j e c t i o n

p r o j e c t i n t h e Phosphoria Formation was d i s c o n t i n u e d because of mechanical and s a f e t y problems r e l a t e d t o t h e handling of hydrogen s u l f i d e r i c h "sour gas." t h e F r o n t i e r Formation.

The o t h e r was a water i n j e c t i o n p r o j e c t i n The p r o j e c t was s t a r t e d i n 1961, b u t was

d i s c o n t i n u e d i n 1966, due t o a l a c k of i n j e c t a b l e water.

There was

a l s o no evidence of i n c r e a s e d production from t h e F r o n t i e r a s a r e s u l t of water i n j e c t i o n . A s a l t w a t e r d i s p o s a l w e l l , p e r f o r a t e d i n t h e Phosphoria and Tensleep f o r m a t i o n s , was placed i n o p e r a t i o n d u r i n g 1979.

The t o p of

t h e Phosphoria Formation i s encountered a t a depth of 8,620 f e e t i n t h e S i l v e r Tip a r e a .

Cumulative i n j e c t i o n and average p r e s s u r e d a t a

were n o t a v a i l a b l e a t t h e time of t h i s w r i t i n g . Casing Record:

S a l t Water D i s p o s a l Well #37, T58N-R100W-28, S i l v e r F i e l d , S i l v e r Tip U n i t , T o t a l Depth = 8815 f e e t .

Casing S i z e

Depth S e t

13-3/8"

367'

275 s a c k s

8620'

600 sacks

7"

Cement

Simpson Ranch F i e l d (160,570 b b l s o i l , 38,374 MCF gas; 1971-79) Simpson Ranch Unit The Simpson Ranch Unit of Simpson Ranch F i e l d i s t h e s i t e of a two w e l l water i n j e c t i o n p r o j e c t completed i n t h e Minnelusa Formation a t a depth of about 7,850 f e e t .

The waterflood was i n i t i a t e d i n 1979,

and i s operated by Davis O i l Company.

The Minnelusa r e s e r v o i r a t

Simpson Ranch F i e l d h a s an average p o r o s i t y of 12.6 p e r c e n t . Cumulative i n j e c t i o n d a t a were r e p o r t e d only f o r t h e #1w e l l . A s of November, 1979, 120,527 b a r r e l s (5,012,634 g a l l o n s ) of water from t h e Fox H i l l s Sandstone had been i n j e c t e d through t h a t w e l l .

The

o t h e r i n j e c t i o n w e l l ( # 3 ) has been temporarily shut-in.

Casing Record:

I n j e c t i o n Well #3, T51N-R69W-15 bdd, Simpson Ranch F i e l d , Simpson Ranch U n i t , T o t a l Depth = 7960 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

9-5 / 8"

36

13-L/2"

305 '

300 sacks

5-1/2"

15.5

8-3/4"

7960'

350 sacks

S k u l l Creek F i e l d (10,807,674 b b l s o i l , 1,417,608 MCF gas; 1946-79) S k u l l Creek F i e l d , l o c a t e d approximately seven m i l e s southwest of Newcastle, i n Townships 44 and 45 North, Range 62 West, Weston County, was discovered i n A p r i l , 1946.

The discovery w e l l was completed i n

t h e Lower Cretaceous Newcastle Sandstone. The p r o d u c t i v e r e s e r v o i r c o n s i s t s of t h r e e o r f o u r porous i n t e r v a l s i n some a r e a s of S k u l l Creek F i e l d , and only one i n t e r v a l i n o t h e r s e c t i o n s of t h e f i e l d .

S t r a t i g r a p h i c c r o s s - s e c t i o n s based on e l e c t r i c

l o g s i n d i c a t e t h a t t h e s e p a r a t e i n t e r v a l s merge i n some a r e a s , thereby forming a common o i l r e s e r v o i r .

This has been f u r t h e r s u b s t a n t i a t e d

by t h e production h i s t o r y of t h e r e s e r v o i r .

The Newcastle sand v a r i e s i n composition from a c l e a n sand t o a s h a l e y sand w i t h , i n some c a s e s , a c o n s i d e r a b l e amount of carbonaceous m a t e r i a l .

The average depth t o t h e Newcastle Sandstone a t S k u l l

Creek i s about 3,300 f e e t . S t r u c t u r a l contours, on t h e top of t h e Newcastle Sandstone, r e v e a l a monoclinal s t r u c t u r e w i t h a g e n t l e d i p of 150 f e e t p e r m i l e t o t h e southwest.

The p r o d u c t i v e l i m i t s of t h e r e s e r v o i r a r e d e f i n e d ,

p r i m a r i l y , by sand pinchouts, except t o t h e southwest, where an o i l water c o n t a c t i s encountered. S i x s e p a r a t e water i n j e c t i o n p r o j e c t s a r e c u r r e n t l y o p e r a t i n g a t S k u l l Creek F i e l d and another waterflood a t North S k u l l Creek F i e l d is also active.

A l l of t h e i n j e c t i o n w e l l s were completed by cement-

i n g c a s i n g through t h e productive i n t e r v a l and s e l e c t i v e l y p e r f o r a t i n g i n t h e o b j e c t i v e sand. S k u l l Creek Unit The S k u l l Creek Unit of S k u l l Creek F i e l d introduced t h e f i r s t Newcastle r e s e r v o i r waterflood i n 1965.

The one w e l l i n j e c t i o n

p r o j e c t was expanded i n subsequent y e a r s , and by 1968, included 11 i n j e c t i o n w e l l s completed i n t h e Newcastle Sandstone a t depths between 3,100 and 3,400 f e e t . The Newcastle r e s e r v o i r covers 1 , 5 4 1 a c r e s w i t h an average pay zone t h i c k n e s s of about 12 f e e t .

Reservoir behavior i n d i c a t e s t h a t t h e

primary mechanism of production h a s been by s o l u t i o n gas d r i v e and t h a t t h e l e n t i c u l a r c h a r a c t e r of t h e sand bodies has i n h i b i t e d a c c e s s t o any s i g n i f i c a n t n a t u r a l water d r i v e . 1946, was 1,385 p s i .

The i n i t i a l r e s e r v o i r p r e s s u r e , i n

A bottom h o l e p r e s s u r e survey i n November, 1957,

showed t h a t t h e r e s e r v o i r p r e s s u r e had d e c l i n e d t o 978 p s i .

The bottom

h o l e p r e s s u r e was e s t i m a t e d a t 100 t o 200 p s i i n 1964. I n o r d e r t o i n c r e a s e t h e r e s e r v o i r p r e s s u r e and enhance o i l production from t h e Newcastle r e s e r v o i r , water i n j e c t i o n was i n i t i a t e d . The water supply f o r t h e f l o o d i s obtained from w e l l s i n t h e Lakota and Dakota sands.

A s of December, 1979, 17,257,191 b a r r e l s (7.248 x

8 10 g a l l o n s ) had been i n j e c t e d s i n c e t h e p r o j e c t s t a r t e d .

Average

i n j e c t i o n p r e s s u r e s during t h a t time ranged from 225 t o 2,215 p s i . Casing Record:

I n j e c t i o n Well #26, T44N-R62W-22 bb, S k u l l Creek F i e l d , S k u l l Creek U n i t , T o t a l Depth = 3375 f e e t .

Casing S i z e

Wt.

( m t )

Amount

Perforations

8-5 / 8"

24

151.12 "

None

5-112"

14

3374.26 "

3302-3306'

Purpose Surface Injection

Newcas t l e Unit The Newcastle Unit of S k u l l Creek F i e l d covers an a r e a of 2,200 acres: 880 a c r e s of f e d e r a l l a n d , 220 a c r e s of s t a t e land, and 1,100 a c r e s of p r i v a t e l y owned f e e land.

A water i n j e c t i o n p r o j e c t a t t h e

u n i t was s t a r t e d i n 1970, and i s operated by Texaco, I n c . The Newcastle Sandstone i s found a t a depth of around 3,000 f e e t i n t h e u n i t p a r t i c i p a t i n g a r e a , h a s average t h i c k n e s s of 50 f e e t , and an average pay zone t h i c k n e s s of 8 t o 38 f e e t n e a r t h e bottom of t h e formation.

Analyses of c o r e s i n d i c a t e an average r e s e r v o i r p o r o s i t y

and p e r m e a b i l i t y of 15.8 p e r c e n t and 89 m i l l i d a r c i e s , r e s p e c t i v e l y . I n j e c t i o n began i n n i n e w e l l s during 1970, and by 1975, t h e p r o j e c t had been expanded t o 12 w e l l s .

A s of December, 1979, t h r e e of t h e

w e l l s were shut-in and cumulative i n j e c t i o n t o t a l e d 6,505,138 b a r r e l s

8 (2.7322 x 10 g a l l o n s ) of water from t h e Dakota sand.

Average i n j e c t i o n

p r e s s u r e s have n o t exceeded 1,950 p s i during t h e f i r s t t e n y e a r s of injection.

Casing Record:

I n j e c t i o n Well #D-511, T44N-R62W-11 c a a , S k u l l Creek F i e l d , Newcastle U n i t , T o t a l Depth = 2980 f e e t .

Casing S i z e

Wt.

10-3/4" 7I'

(#/ft)

Amount

32.75

154.67'

20

2977.58'

Purpose Surface Injection

Donielson Unit Water i n j e c t i o n a t t h e Donielson Unit of S k u l l Creek F i e l d was s t a r t e d i n 1974, by Grace Petroleum Company.

A l l of t h e seven i n j e c t i o n

w e l l s a r e l o c a t e d i n Section 1 0 , Township 44 North, Range 62 West, Water from t h e Fox H i l l s Sandstone i s i n j e c t e d i n t o t h e

Weston County.

Newcastle r e s e r v o i r a t a depth of j u s t over 3,000 f e e t .

Six of t h e

seven e x i s t i n g w e l l s were a c t i v e l y i n j e c t i n g during t h e l a s t s i x months of 1979; however, cumulative i n j e c t i o n volumes were n o t a v a i l a b l e from t h e i n j e c t i o n r e p o r t s on f i l e a t t h e O i l and Gas Commission.

Average

i n j e c t i o n p r e s s u r e s have ranged between 1,000 and 1,700 p s i during t h e f i r s t s i x years. Casing Record: Casing S i z e

I n j e c t i o n Well #w-8, T44N-R62W-10 dcb, S k u l l Creek F i e l d , Donielson U n i t , T o t a l Depth = 3114 f e e t . Wt.

(#/ft)

7" 4-1/2"

Hole S i z e 9"

9.5

6-114"

Depth S e t

Cement

106 '

60 sacks

3100 '

100 sacks

Purpose Surface Injection

Bock Unit The Bock Unit of S k u l l Creek F i e l d i s operated by L and R D r i l l i n g Company, and i s c u r r e n t l y (June, 1980) t h e s i t e of a f i v e w e l l water injection project.

The w e l l s a r e l o c a t e d i n Sections 5 , 7 , and 8 ,

Township 44 North, Range 62 West, Weston County.

During t h e l a s t s i x

months of 1979, t h r e e of t h e w e l l s were a c t i v e l y i n j e c t i n g water from t h e Dakota and Lakota sands i n t o t h e Newcastle Sandstone r e s e r v o i r . Cumulative i n j e c t i o n between 1970 and December, 1979, amounted t o 456,064 b a r r e l s (1.9154 x LO

7

g a l l o n s ) of water i n j e c t e d a t average

p r e s s u r e s ranging from 110 t o 1,695 p s i . Casing Record: Casing S i z e 5-1/2"

I n j e c t i o n Well #12W, T44N-R62W-7 dac, S k u l l Creek F i e l d , Bock U n i t , T o t a l Depth = 3490 f e e t . (#/ft)

Wt.

15.5

Hole S i z e 8-3/4"

Depth S e t

Cement

Purpose

3490'

150 sacks

Injection String

South Unit The South Unit of S k u l l Creek F i e l d covers 960 a c r e s of f e d e r a l land and, s i n c e 1966, has been operated by American P e t r o f i n a .

A

waterflood p i l o t p r o j e c t s t a r t e d i n 1966, and was expanded t o a f u l l s c a l e , f i v e w e l l flood by 1972.

Water f o r t h e i n j e c t i o n p r o j e c t i s

provided by a supply w e l l completed i n t h e Lakota Sandstone.

Cumulative

8 i n j e c t i o n , through December, 1979, was 5,655,017 b a r r e l s (2.3751 x 10 g a l l o n s ) of water.

The maximum average i n j e c t i o n p r e s s u r e reached

during t h e l a s t 14 y e a r s of i n j e c t i o n was 2,250 p s i .

Casing Record:

I n j e c t i o n Well #3-27, T44N-R62W-27 c a , S k u l l Creek F i e l d , South U n i t , T o t a l Depth = 3380 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

8-5/8"

24

153'

4-1/2"

9.3

3380'

Perforations

Purpose Surf a c e

3311-3314'

Injection

North S k u l l Creek F i e l d (1,409,042 b b l s o i l , 1,381,553 MCF g a s ; 1946-79) North Unit North S k u l l Creek F i e l d i s l o c a t e d i n Township 45 North, Range 62 A p i l o t waterflood was p u t i n t o o p e r a t i o n i n 1972,

West, Weston County.

and was expanded t o a n i n e w e l l system during t h e next y e a r .

A11

i n j e c t i o n w e l l s a r e p e r f o r a t e d i n t h e Newcastle Sandstone between 2,850 and 3,100 f e e t .

Water f o r t h e flood i s pumped from t h e Newcastle and

Lakota sandstones.

A s of December, 1979, 2,457,170 b a r r e l s (1.032 x

8 10 g a l l o n s ) had been i n j e c t e d i n t o t h e Newcastle r e s e r v o i r .

Injection

p r e s s u r e s averaged over each s i x month period of i n j e c t i o n a t each w e l l , ranged from 26 t o 1,704 p s i .

During t h e second h a l f of 1979, e i g h t of

t h e w e l l s were a c t i v e l y i n j e c t i n g . S l i c k Creek F i e l d (4,722,094 b b l s o i l , 6,592,426 MCF gas; 1950-79) S l i c k Creek Unit S l i c k Creek F i e l d was discovered on October 8, 1950, when a producing w e l l was completed i n t h e Phosphoria Formation.

It began

producing a t a r a t e of 732 b a r r e l s of o i l and 797,000 cubic f e e t of sour (19.8 p e r c e n t hydrogen s u l f i d e ) gas per day. about two and one-half

The f i e l d i s l o c a t e d

m i l e s s o u t h e a s t of Worland i n Sections 32 t o 35,

Township 47 North, Range 92 West, and S e c t i o n s 2 and 3 , Township 46 North, Range 92 West, Washakie County.

Core a n a l y s e s of t h e Phosphoria

i n d i c a t e t h a t t h e average e f f e c t i v e p o r o s i t y of t h e producing zone

(10,460 t o 10,554 f e e t i n t h e discovery w e l l ) i s 9 percent. f e e t , near t h e bottom of t h e cored zone, t e s t e d permeable.

Only 26 The Phosphoria

r e s e r v o i r a r e a covers 1,967 a c r e s w i t h an average pay zone t h i c k n e s s of 20 f e e t . S l i c k Creek F i e l d was u n i t i z e d f o r o p e r a t i o n i n J u l y , 1950, w i t h Mobil O i l Corporation a s u n i t o p e r a t o r . committed t o t h e Unit.

A t o t a l of 3,675 a c r e s i s

I n j e c t i o n of water, purchased from t h e C i t y of

Worland, i n t o t h e Phosphoria Formation and t h e Muddy Sandstone, s t a r t e d i n J u l y , 1965.

Recent d a t a from S l i c k Creek were u n a v a i l a b l e .

As

8 of January, 1970, 3,234,016 b a r r e l s (1.3583 x 10 g a l l o n s ) of water had been i n j e c t e d through two of t h e t h r e e w e l l s . reconverted f o r production.

One of t h e w e l l s was

Average i n j e c t i o n p r e s s u r e s have ranged

from 1,600 t o 2,850 p s i . I n 1970, Tenneco O i l Company s t a r t e d d i s p o s i n g of produced s a l t water from t h e Phosphoria Formation through a w e l l l o c a t e d i n Section 35, Township 46 North, Range 92 West, Washakie County. completed i n t h e Cody Shale a t an unreported depth.

The w e l l i s

F u r t h e r d e t a i l s on

t h e d i s p o s a l system were u n a v a i l a b l e a t t h e time of t h i s w r i t i n g . Casing Record:

I n j e c t i o n Well #8, T47N-R92W-34 bdd, S l i c k Creek F i e l d , S l i c k Creek U n i t , T o t a l Depth = 10,553 f e e t .

Casing S i z e

Top of Cement

Amount

500'

360 sacks

7"

10375'

400 sacks

5"

3000 '

13-3/8"

Spence Dome F i e l d (353,401 b b l s o i l ; 1944-79) Koch Production Company s t a r t e d t h e o p e r a t i o n of a p a i r of s i n g l e w e l l s a l t water d i s p o s a l systems i n t h e Spence Dome and Western Giant

u n i t s of Spence Dome F i e l d d u r i n g 1976.

Spence Dome F i e l d i s l o c a t e d

i n Township 54 North, Range 94 West, Big Horn County. a r e completed i n t h e Madison Limestone.

Both systems

Cumulative i n j e c t i o n t o t a l s

are o n l y a v a i l a b l e f o r t h e Spence Dome U n i t system and i n d i c a t e t h a t 2,081,056 b a r r e l s (8.7404 x LO

7

g a l l o n s ) of produced b r i n e from Spence

Dome F i e l d had been i n j e c t e d as of December, 1979.

Injection pressures

have n o t exceeded 1 0 p s i d u r i n g t h e f o u r y e a r s of r e c o r d . South S p r i n g Creek F i e l d (12,486,841 b b l s o i l , 1 , 4 0 2 MCF g a s ; 1929-79) I n 1965, Texaco, I n c . i n i t i a t e d t h e f i r s t of two s a l t w a t e r d i s p o s a l systems a t South S p r i n g Creek F i e l d i n Township 49 North, Range 102 .West, P a r k County.

The f i r s t system c o n s i s t e d of two w e l l s i n t h e

South S p r i n g Creek U n i t of t h e f i e l d . Both w e l l s were completed i n t h e Madison Limestone a t d e p t h s of 4,640 and 4,840 f e e t , r e s p e c t i v e l y .

As of December, 1978, b o t h w e l l s

were on a c t i v e s t a t u s and t h e c u m u l a t i v e volume of i n j e c t e d b r i n e w a s 9 204,063,019 b a r r e l s (8.5706 x 1 0 g a l l o n s ) . The second d i s p o s a l system began i n j e c t i n g produced s a l t w a t e r t o t h e Madison Limestone through one w e l l i n 1976.

The w e l l i s completed

a t a d e p t h of 4,570 f e e t and open t o t h e f o r m a t i o n f o r 280 f e e t .

The

d i s p o s a l w e l l i s l o c a t e d i n t h e P h e l p s U n i t of South S p r i n g Creek F i e l d i n S e c t i o n 2, Township 49 North, Range 102 West, P a r k County.

A s of

8 December, 1978, 21,954,269 b a r r e l s (9.2208 x 1 0 g a l l o n s ) of b r i n e had been i n j e c t e d i n t o t h e Madison s i n c e t h e system began o p e r a t i n g .

Casing Record:

S a l t Water Disposal Well #7, T49N-R102W-12, South Spring Creek F i e l d , South Spring Creek Unit, T o t a l Depth = 4771 f e e t .

Casing S i z e 13-3/8"

Wt.

(#/ft)

Depth S e t

Cement

236 '

190 sacks

4750'

421 sacks

48,54.5

9-51 8"

36,40

Springen Ranch F i e l d (9,396,961 b b l s o i l , 13,909,559 MCF gas; 1968-79) Muddy Unit Springen Ranch F i e l d i s l o c a t e d i n Townships 50 and 5 1 North, Range 71 West, Campbell County.

The f i e l d was discovered i n 1968, when

a p r o d u c t i v e o i l w e l l was completed i n t h e Muddy Sandstone.

I n the

Springen Ranch a r e a , t h e p o r o s i t y and p e r m e a b i l i t y of t h e Muddy r e s e r voir a r e highly variable.

Core samples from Muddy i n j e c t i o n w e l l s

show p o r o s i t i e s ranging from 2 t o 15 p e r c e n t and p e r m e a b i l i t i e s t h a t average between 2.4 and 588 m i l l i d a r c i e s . A water i n j e c t i o n p r o j e c t , operated by Amoco Production Company,

s t a r t e d i n 1973, a t t h e Muddy Unit of Springen Ranch F i e l d .

Sixteen

w e l l s began i n j e c t i n g water t o t h e Muddy r e s e r v o i r a t an average depth of about 7,600 f e e t .

One w e l l was added t o t h e system i n 1976, and

f o u r more w e l l s began i n j e c t i n g i n 1977.

Water f o r t h e p r o j e c t i s

obtained from t h e Fox H i l l s Sandstone and Lance Formation and from producing w e l l s i n t h e Muddy Sandstone. I n j e c t i o n r e p o r t s from November, 1979, i n d i c a t e t h a t a cumulative 8 volume of 16,655,552 b a r r e l s (6.9953 x 1 0 g a l l o n s ) of water have been

i n j e c t e d s i n c e t h e p r o j e c t began i n 1973.

Due t o t h e l i t h o l o g i c

v a r i a t i o n w i t h i n t h e Muddy r e s e r v o i r , average i n j e c t i o n p r e s s u r e s have ranged between 100 and 2,800 p s i .

During t h e l a s t period covered by t h e

i n j e c t i o n r e p o r t s (May t o November, 1979), 11 of t h e w e l l s were temporarily shut-in.

Casing Record:

Casing S i z e

I n j e c t i o n W e l l #16, T51N-R71W-27 dbb, Springen Ranch F i e l d , Muddy U n i t , T o t a l Depth = 7695 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-518"

24

12-114''

348'

150 sacks

Surface

5-112''

15.5,17

7-718"

7695'

250 sacks

Injection

East S t a r C o r r a l F i e l d (1,631,007 b b l s o i l , 2,508,095 MCF gas; 1961-79) Long I s l a n d Unit The i n j e c t i o n of water i n t o t h e Almy sands of t h e Wasatch Formation began i n 1969, i n o r d e r t o enhance o i l production from t h e r e s e r v o i r a t East S t a r Corral Field.

The f i e l d i s l o c a t e d i n Township 30 North,

Range 112 West, S u b l e t t e County, and was discovered i n 1961. Belco Petroleum Corporation, o p e r a t o r of t h e Long I s l a n d Unit of E a s t S t a r C o r r a l F i e l d , i n i t i a t e d t h e waterflood using f o u r i n j e c t i o n w e l l s completed i n t h e Almy sands a t depths ranging from 1,500 t o 3,500 feet.

Water f o r t h e p r o j e c t is s u p p l i e d by f o u r w e l l s i n t h e Knight

sand i n t h e upper Wasatch Formation.

A l l of t h e supply w e l l s a r e

l o c a t e d i n S e c t i o n 1 9 , Township 30 North, Range 112 West. Cumulative i n j e c t i o n d a t a through December, 1979, i n d i c a t e d t h a t 8 7,333,013 b a r r e l s (3.0799 x 10 g a l l o n s ) of water had been i n j e c t e d a t

average p r e s s u r e s between 500 and 2,650 p s i .

S i x of t h e e i g h t i n j e c t i o n

w e l l s were a c t i v e during t h e l a s t h a l f of 1979. temporarily shut-in.

The o t h e r two were

One of t h e w e l l s i s d u a l l y p e r f o r a t e d i n t h e

S t r a y 3 and 4 sands of t h e Wasatch Formation, a t depths of 3,325 and 3,520 f e e t .

Casing Record:

I n j e c t i o n Well #31, T30N-R112W-20 ccc, East S t a r C o r r a l F i e l d , Long I s l a n d U n i t , T o t a l Depth = 3631 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5/8"

24

4-1/2"

10.5,11.6

Hole S i z e

Depth S e t

Cement

202 '

100 sacks

11" 7-7/8"

3620'

150 sacks (50-50 pozmix)

Steamboat Butte F i e l d (78,658,959 b b l s o i l , 10,152,385 MCF gas; 1943-79) Steamboat B u t t e F i e l d i s l o c a t e d on t h e Wind River Indian Reservat i o n , about t h r e e and one-half m i l e s northwest of P i l o t Butte o i l f i e l d , i n Townships 3 and 4 North, Range 1 West, Fremont County.

Between

1943 and 1948, o i l was discovered i n t h e Nugget Sandstone, t h e Tensleep Sandstone, t h e Lakota Sandstone, t h e t h i r d F r o n t i e r sand and t h e Phosphoria Formation.

T r i b a l Unit Due t o r a p i d l y d e c l i n i n g bottom h o l e p r e s s u r e s i n t h e Tensleep r e s e r v o i r , water i n j e c t i o n i n t o t h e r e s e r v o i r was s t a r t e d i n 1952. The p r o j e c t c o n s i s t e d of only one w e l l u n t i l 1962, when t h r e e i n j e c t i o n

w e l l s were added t o t h e Tensleep waterflood. The Tensleep r e s e r v o i r i s encountered a t depths between 6,800 and 7,300 f e e t i n t h e T r i b a l Unit a r e a and covers about 1,270 a c r e s , w i t h an average pay zone t h i c k n e s s of about 200 f e e t .

Average p o r o s i t y and

p e r m e a b i l i t y from two Tensleep Sandstone c o r e samples a r e 12 t o 1 3 p e r c e n t and 38 t o 45 m i l l i d a r c i e s , r e s p e c t i v e l y . The T r i b a l Unit i n j e c t i o n w e l l s a r e l o c a t e d i n S e c t i o n s 1 9 , 29, 32, and 33, Township 4 North, Range 1 West, Fremont County.

The water-

f l o o d p r o j e c t c u r r e n t l y c o n s i s t s of s i x a c t i v e d u a l i n j e c t i o n w e l l s .

As of December, 1979, a c u m u l a t i v e volume of 145,462,207 b a r r e l s 9 (8.2093 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d from s h a l l o w w e l l s n e a r t h e Wind R i v e r and T e n s l e e p producing w e l l s a t Steamboat B u t t e . Average i n j e c t i o n p r e s s u r e s have ranged from a minimum of 350 t o a maximum o f 4,885 p s i . The Phosphoria r e s e r v o i r of t h e T r i b a l U n i t c o v e r s a n a r e a of a b o u t 900 a c r e s w i t h a n a v e r a g e pay zone t h i c k n e s s of about 40 f e e t . Water i n j e c t i o n i n t o t h e r e s e r v o i r s t a r t e d i n November, 1962, through t h r e e w e l l s which a r e d u a l l y completed i n t h e Phosphoria and Tensleep reservoirs.

By 1979, t h e w a t e r f l o o d i n c l u d e d t e n w e l l s , f i v e of which

a r e dual injectors.

Cumulative i n j e c t i o n through December of t h a t

9 y e a r was 41,554,475 b a r r e l s (1.7453 x 1 0 g a l l o n s ) of w a t e r produced The

by s h a l l o w s u p p l y w e l l s and Phosphoria o i l p r o d u c t i o n w e l l s .

a v e r a g e i n j e c t i o n p r e s s u r e s a t e a c h w e l l , averaged over each six-month p e r i o d of i n j e c t i o n , have ranged between 1,565 and 3,195 p s i .

Six

of t h e t e n w e l l s were a c t i v e l y i n j e c t i n g d u r i n g t h e l a s t s i x months of 1979. Casing Record:

I n j e c t i o n W e l l #V-1, T4N-R1W-33 c c c , Steamboat B u t t e F i e l d , T r i b a l U n i t , T o t a l Depth = 7496 f e e t .

Casing S i z e

Wt.

10-314" 7"

(#/ft)

Amount

32.75

243'

20,23

7494'

Perforations

Purpose Surf a c e

6970-7015'

Injection

Casing Record:

I n j e c t i o n W e l l /,c-16, T4N-R1W-32 bdb, Steamboat B u t t e F i e l d , T r i b a l U n i t , T o t a l Depth = 7038 f e e t .

Casing S i z e

wt.

16" 10-314" 7"

(#/ft)

Hole S i z e

Depth S e t

Cement

55

19-114"

92'

100 s a c k s

40.5

13-314"

771'

425 s a c k s

7041'

600 s a c k s

23

9"

Tribal-Brinkerhoff

Unit

The Tribal-Brinkerhoff

Unit of Steamboat Butte F i e l d i s l o c a t e d i n

Township 3 North, Range 1 West, Fremont County.

Water i n j e c t i o n t o t h e

Phosphoria Formation s t a r t e d i n 1970, through one w e l l p e r f o r a t e d a t a depth of 6,709 f e e t .

The water f o r t h e p r o j e c t i s provided by shallow

supply w e l l s near t h e Wind River and by o i l producing w e l l s i n t h e Phosphoria. Another w e l l was added i n 1977.

Cumulative i n j e c t i o n through both

8 w e l l s , a s of December, 1979, was 6,103,450 b a r r e l s (2.5634 x 10 g a l l o n s ) of f r e s h and produced water.

Average i n j e c t i o n p r e s s u r e s have

been high r e l a t i v e t o o t h e r p r o j e c t s around Wyoming, ranging from 1,900 t o 3,055 p s i . Casing Record:

I n j e c t i o n W e l l #6, T3N-RlW-9 bcd, Steamboat Butte F i e l d , Tribal-Brinkerhoff U n i t , T o t a l Depth = 6988 f e e t .

Casing S i z e 10-3 14" 7"

Wt.

(#/ft)

Arnoun t

32

510'

23

6904'

Stewart F i e l d (7,857,638 b b l s o i l , 1,138 MCF gas; 1965-79) Minnelusa "B"

Sand Unit

I n 1965, o i l was discovered i n t h e Minnelusa Formation underlying Stewart F i e l d .

The f i e l d i s l o c a t e d i n Townships 50 and 5 1 North,

Range 69 West, Campbell County.

Water i n j e c t i o n t o t h e Minnelusa "B"

sand s t a r t e d i n 1970, through f o u r w e l l s .

By 1976, t h e r e were 1 3 w e l l s

i n j e c t i n g water from supply w e l l s i n t h e Fox H i l l s and Minnelusa formations and from production w e l l s a t Pan Am Windmill F i e l d and t h e e a s t and s o u t h b a t t e r i e s of Stewart F i e l d .

The d e p t h t o t h e Minnelusa "Btt sand a t Stewart F i e l d ranges from 7,900 t o 8,100 f e e t .

The p o r o s i t y of t h e r e s e r v o i r was determined from

c o r e samples a t f o u r of t h e i n j e c t i o n w e l l s and ranges from 5.8 t o 14.8 p e r c e n t .

P e r m e a b i l i t y e s t i m a t e s were made a t two w e l l s and

ranged from 10.7 t o 134 m i l l i d a r c i e s . Eleven of t h e w e l l s were i n j e c t i n g during t h e f i r s t s i x months of 1979.

The remainder were temporarily shut-in.

The t o t a l volume of

water i n j e c t e d between 1970 and J u l y , 1979, was 23,550,769 b a r r e l s 8 (9.8913 x 10 g a l l o n s ) .

I n j e c t i o n p r e s s u r e s , averaged over each s i x -

mont period of i n j e c t i o n a t each w e l l , ranged from 1,500 t o 2,900 p s i . Casing Record:

Casing S i z e

I n j e c t i o n Well #22, T5lN-R69W-34 bb(cd), Stewart F i e l d , Minnelusa "Bt' Sand U n i t , T o t a l Depth = 8185 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-5 / 8"

28

12-1/4"

198 '

150 sacks

Surface

4-112"

9.5,10.5,11.6

7-7/8"

8181'

450 sacks

Injection

Sussex F i e l d (62,355,722 b b l s o i l , 13,744,239 MCF gas; 1948-79) The Sussex o i l f i e l d i s l o c a t e d i n Johnson County, Township 42 North, Ranges 78 and 79 West.

The f i e l d was discovered i n 1948, w i t h

t h e completion of a w e l l i n t h e Lakota Sandstone.

Subsequent o i l

d i s c o v e r i e s were made during t h e n e x t f i v e y e a r s i n t h e Shannon, Sussex, Tensleep, second F r o n t i e r , f i r s t F r o n t i e r , Sundance, and Parkman sands. The C o n t i n e n t a l O i l Company i s t h e o p e r a t o r of Sussex F i e l d which covers 13,376 a c r e s . I ~ D ,I t

IIE,

It

and

t t ~ I. t

The f i e l d i s divided i n t o a r e a s "A,"

"B,"

"C,"

Various u n i t s a r e l o c a t e d w i t h i n each a r e a l i s t e d

above, and a r e producing from t h e Shannon, Sussex, Tensleep, o r o t h e r formations.

Seven w a t e r f l o o d s were s t i l l a c t i v e l y i n j e c t i n g a s of

December, 1979.

Geologic c o n d i t i o n s which i n f l u e n c e t h e w a t e r f l o o d p r o j e c t s d i f f e r f o r e a c h u n i t and may n o t b e g e n e r a l i z e d over t h e e n t i r e f i e l d . S e v e r a l w e l l s completed i n t h e Madison Limestone p r o v i d e t h e f r e s h w a t e r s u p p l y f o r t h e i n j e c t i o n w e l l s v i a t h e S h i l o h Water Supply System.

Sussex "A" U n i t The Sussex "A" U n i t c o v e r s 370 a c r e s of f e d e r a l l y owned l a n d . Sussex "A"

18 f e e t .

The

r e s e r v o i r i n c l u d e s 306 a c r e s w i t h a n a v e r a g e pay t h i c k n e s s of The i n i t i a l producing mechanism of t h e r e s e r v o i r was s o l u t i o n

gas d r i v e . I n 1951, a p i l o t w a t e r f l o o d p r o j e c t w a s i n i t i a t e d .

The p i l o t s t u d y

expanded t o a f u l l s c a l e p r o j e c t i n 1957, and e v e n t u a l l y i n c l u d e d t e n i n j e c t i o n w e l l s set i n a p e r i p h e r a l f l o o d p a t t e r n which conformed t o t h e existing f a u l t pattern i n the area.

By 1979, a l l of t h e i n j e c t o r s had

been s h u t - i n . Casing Record:

I n j e c t i o n Well #45, T42N-R78W-17 a c b , Sussex F i e l d , Sussex "A" U n i t , T o t a l Depth = 4574 f e e t .

Casing S i z e

Wt.

( m t )

Depth S e t

Cement

9-5/8"

36

174'

150 s a c k s

7"

23

4574'

300 s a c k s

Sussex "C"

Unit

The Sussex "C"

U n i t i n c l u d e s 480 a c r e s of which 240 a c r e s a r e

f e d e r a l l y owned, 140 a c r e s a r e s t a t e owned l a n d , and 100 a c r e s a r e p r i v a t e l y owned f e e l a n d s .

The L a t e C r e t a c e o u s Sussex sand i s found

a t a n a v e r a g e d e p t h o f 4,000 f e e t i n t h e u n i t a r e a .

The a v e r a g e p o r o s i t y

of t h e s a n d s t o n e i s 2 1 p e r c e n t and t h e a v e r a g e p e r m e a b i l i t y t o a i r i s 32 m i l l i d a r c i e s .

The s a n d s t o n e h a s a g r o s s t h i c k n e s s of 40 f e e t and t h e

r e s e r v o i r h a s a maximum c l o s u r e of 500 f e e t .

I n i t i a l reservoir pressure

was 1,545 p s i and t h e o r i g i n a l mechanisms of production were provided by gas cap expansion and s o l u t i o n gas d r i v e .

The s m a l l gas cap i s l o c a t e d

on t h e s t r u c t u r a l c r e s t of t h e r e s e r v o i r .

The Sussex "C"

reservoir

covers 453 a c r e s and has an average pay t h i c k n e s s of 26 f e e t .

It i s a

f a u l t e d a n t i c l i n e which is bounded on t h e south by a major s e a l i n g normal f a u l t and on t h e e a s t , west, and n o r t h by t h e oil-water c o n t a c t and by a s e r i e s of minor southwest-northeast

t r e n d i n g normal f a u l t s .

The

f a u l t i n g d i v i d e s t h e r e s e r v o i r i n t o t h r e e d i s t i n c t f a u l t blocks. Water and gas i n j e c t i o n began i n December, 1959.

A s of March,

8 1979, 13,179,905 b a r r e l s (5.5356 x 10 g a l l o n s ) of water had been i n j e c t e d i n t o t h e Sussex "C"

reservoir.

produced water t o o i l f o r t h e Sussex "C"

The cumulative r a t i o of u n i t i s 0.4 t o 1.0.

"c"

s i x t e e n water i n j e c t i o n w e l l s i n t h e Sussex

Of t h e

U n i t , seven were s t i l l

a c t i v e l y i n j e c t i n g i n June, 1979. Casing Record:

I n j e c t i o n Well #197, T42N-R78W-14 c a c , Sussex F i e l d , Sussex "C" U n i t , T o t a l Depth = 4761 f e e t .

Casing S i z e

Wt.

8-5 / 8"

(#/ft) 24

Hole S i z e

Depth S e t 184 '

12-114"

Cement 150 sacks C 1 . "G" 320 sacks C 1 . "GI'

Sussex "D"

Unit

The producing r e s e r v o i r of t h e Sussex

"Dl1

Unit covers 147 a c r e s

and has an average pay t h i c k n e s s of 33 f e e t . The Sussex Sandstone i n t h i s a r e a i s composed of f i n e - t o mediumg r a i n e d , gray t o green, s a l t and pepper sandstone and i s found a t a depth of approximately 4,255 f e e t . v o i r i s 20.7 p e r c e n t .

The average p o r o s i t y of t h e r e s e r -

The r e s e r v o i r i s a p p a r e n t l y c o n t r o l l e d by a normal d i p - s l i p f a u l t on t h e s o u t h , a w a t e r - o i l c o n t a c t on t h e n o r t h a n d w e s t , a n d a s e r i e s of minor f a u l t s on t h e e a s t .

The o r i g i n a l mechanism of production was

solution gas drive. The waterflood p r o j e c t began h e r e i n 1958, and was expanded t o e i g h t w e l l s i n 1973.

By 1979, only one of t h e w e l l s was a c t i v e l y

The produced w a t e r - o i l r a t i o had i n c r e a s e d t o 27.0 t o 1 i n

injecting.

1978, compared t o a cumulative r a t i o of 1.2 t o 1 s i n c e i n j e c t i o n began. Casing Record:

I n j e c t i o n W e l l #70, T42N-R79W-12 ddd, Sussex F i e l d , Sussex "D" U n i t , T o t a l Depth = 4600 f e e t .

Casing S i z e

Wt.

(#/ft)

9-5/8"

26

5-1/2"

14

Depth S e t

Cement

171'

150 sacks

Surface

300 sacks

Injection

4599

Purpose

Shannon "A" Unit The Shannon "A" Unit covers 420 a c r e s of f e d e r a l l y owned land. The r e s e r v o i r i n c l u d e s 368 a c r e s and has an average pay t h i c k n e s s of 14 f e e t .

S o l u t i o n gas d r i v e and p a r t i a l n a t u r a l water d r i v e provided

t h e energy f o r i n i t i a l r e s e r v o i r production. A water i n j e c t i o n p i l o t program began i n 1951, and was expanded t o a f u l l s c a l e program i n 1957.

A l l n i n e of t h e w e l l s w e r e d u a l i n j e c t o r s

i n t h e Shannon and Sussex sands when they were shut-in.

A s of 1979,

a l l of t h e w e l l s were e i t h e r temporarily o r permanently s h u t - i n . Cumulative i n j e c t i o n a t t h e time i n t o t h e Shannon "A" Unit was 3,761,787 8 b a r r e l s (1.58 x 10 g a l l o n s ) .

I n t h e s e w e l l s , water i s i n j e c t e d down

t h e tubing under a packer i n t o t h e deeper Shannon sand and down t h e c a s i n g annulus i n t o t h e Sussex sand r e s e r v o i r .

Casing Record:

I n j e c t i o n Well 1/67, T42N-R78W-18 aad, Sussex F i e l d , Shannon "A" Unit, T o t a l Depth = 4570 f e e t .

Casing S i z e

Wt.

(I'//ft)

Depth S e t

Cement

9-5 /8"

26

173'

150 sacks

5-1/2"

14

4570'

300 sacks

Shannon "c-E"

Unit

The Shannon "C-Elt

Unit i n c l u d e s 1,030 acres--370

a c r e s of f e d e r a l

l a n d , 480 a c r e s of s t a t e l a n d , and 180 a c r e s of p r i v a t e l y owned f e e land.

The Shannon "C-E"

pay t h i c k n e s s of 12 f e e t .

r e s e r v o i r covers 867 ac'res w i t h an average The average p o r o s i t y and p e r m e a b i l i t y of t h e

Shannon a r e 12.4 p e r c e n t and 2 m i l l i d a r c i e s , r e s p e c t i v e l y . The Shannon Sandstone i s an Upper Cretaceous sand which i s found a t an average depth of 4,350 f e e t i n t h i s u n i t a r e a .

The r e s e r v o i r i s

a f a u l t e d a n t i c l i n e which i s s e a l e d on t h e s o u t h by a normal f a u l t . It i s bounded on t h e o t h e r t h r e e s i d e s by a n oil-water c o n t a c t and o t h e r

minor f a u l t s .

Faulting divides the reservoir i n t o f i v e d i s t i n c t f a u l t

blocks w i t h l i t t l e h y d r a u l i c communication between them.

The Shannon

sand has a g r o s s t h i c k n e s s of 40 f e e t w i t h a maximum c l o s u r e of 500 f e e t . The water i n j e c t i o n p r o j e c t i n t h e Shannon "C-E"

Unit began i n

1959, and was expected t o provide an a d d i t i o n a l 836,000 b a r r e l s of secondary o i l . T o t a l cumulative i n j e c t i o n a s of June, 1979, was 8,335,601 b a r r e l s 8 (3.5 x 10 g a l l o n s ) of water from t h e Madison Limestone v i a t h e Shiloh Water Supply Line. recent years.

The produced w a t e r - o i l r a t i o h a s i n c r e a s e d i n

I n 1978, t h e r a t i o was 4.6 t o 1, compared t o a cumulative

r a t i o of 0.6 t o 1 s i n c e production began i n 1950.

Casing Record:

I n j e c t i o n Well #56, T42N-R78W-18 bbb, Sussex F i e l d , Shannon "C-E" U n i t , T o t a l Depth = 4458 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

10-3/4"

29

172 '

150 s a c k s

5-1/2"

14

4458'

300 s a c k s

Shannon "D" Unit The Shannon

I'D"

Unit r e s e r v o i r i s a zone which c o n t a i n s t h r e e

benches of sandstone which range i n composition from a gray, sandy s h a l e t o a f i n e - t o medium-grained,

gray, s h a l e y sandstone.

The

Shannon Sandstone i s a t l e a s t 96 f e e t t h i c k and i s found a t a depth of 4,600 f e e t i n t h e Shannon

I'D"

Unit a r e a .

The r e s e r v o i r covers 377 a c r e s

and has an average pay t h i c k n e s s of 38 f e e t .

Average p o r o s i t y i n t h e

Shannon sand i s 18.6 p e r c e n t . The waterflood p r o j e c t i n t h e Shannon was expanded i n 1967 and 1973.

'ID"

Unit began i n 1958, and

A l l of t h e i n j e c t i o n w e l l s a r e d u a l

i n j e c t o r s i n t o t h e Shannon and Sussex sandstones.

Water i s i n j e c t e d

down t h e tubing under a packer i n t o t h e deeper Shannon and down t h e c a s i n g annulus i n t o t h e Sussex.

A s of December, 1979, only one of seven

w e l l s were s t i l l a c t i v e l y i n j e c t i n g water i n t o t h e two sandstones. 8 Cumulative i n j e c t i o n t o t h a t time was 8,830,493 b a r r e l s (3.7088 x 10 gallons)

.

Casing Record:

I n j e c t i o n Well #58, T42N-R79W-13 bab, Sussex F i e l d , Shannon "Dl' Unit, T o t a l Depth = 4796 f e e t .

Casing S i z e 9-5/8"

Wt.

(#/ft) 26

Depth S e t

Cement

173'

150 s a c k s

4225 '

250 s a c k s

4796'

200 s a c k s

Lakota "A" Unit The Lakota "A" Unit i n c l u d e s 200 a c r e s of f e d e r a l l y owned l a n d . The upper p o r t i o n of t h e Lakota "A" r e s e r v o i r i s found a t an average depth of 7,600 f e e t and i s composed of h a r d , fine-grained sand which o v e r l i e s a conglomerate.

Beneath t h e conglomerate i s another h a r d ,

fine-grained sand w i t h d i r t y sand s t r e a k s interbedded throughout t h e interval.

The r e s e r v o i r covers 328 a c r e s w i t h an average pay t h i c k n e s s

of 25 f e e t .

The p o r o s i t y of t h e sandstone was estimated a t 15.8 p e r c e n t .

The i n i t i a l producing mechanism of t h e r e s e r v o i r was f l u i d expansion and p a r t i a l water d r i v e .

Water i n j e c t i o n i n t o t h e Lakota "A" r e s e r v o i r began i n 1951, and continued u n t i l 1955, when t h e only i n j e c t i o n w e l l was shut-in.

In

1967, i n j e c t i o n of water s u p p l i e d by t h e Shiloh Water Line was resumed i n a nearby w e l l which was s t i l l a c t i v e l y i n j e c t i n g i n December, 1979. Cumulative i n j e c t i o n through both w e l l s t o t a l e d 1,858,853 b a r r e l s During t h e f i r s t year of i n j e c t i o n

(78,071,826 g a l l o n s ) a t t h a t time.

through t h e second w e l l , t h e monthly o i l production f i g u r e s d i d not show any response t o t h e water i n j e c t i o n . Casing Record:

I n j e c t i o n Well #91, T42N-R78W-17 da, Sussex F i e l d , Lakota "A" U n i t , T o t a l Depth = 9115 f e e t .

Casing S i z e 10-314" 7"

Wt.

(#/ft)

Depth S e t

Cement

32

299'

350 sacks

23

9115 '

625 sacks

Tensleep "A" Unit The Tensleep "A" Unit covers 340 a c r e s of f e d e r a l land which o v e r l i e s t h e Tensleep r e s e r v o i r .

The Tensleep "A"

reservoir contains

320 a c r e s w i t h an average pay t h i c k n e s s of 35 f e e t .

The o r i g i n a l

r e s e r v o i r energy was provided by a n a t u r a l water d r i v e . The water i n j e c t i o n p r o j e c t on t h e Tensleep "A" r e s e r v o i r began One of t h o s e w e l l s i s s t i l l a c t i v e a s a d u a l

i n 1958, w i t h two w e l l s .

i n j e c t o r i n t o t h e Tensleep "A" and Lakota "A" r e s e r v o i r s .

The i n j e c t i o n

p r o j e c t was expanded t o i n c l u d e seven i n j e c t o r s , f i v e of which were a c t i v e a s of December, 1979.

Cumulative i n j e c t i o n up t o t h a t time was

8 20,457,038 b a r r e l s (8.592 x 10 g a l l o n s ) . Casing Record:

I n j e c t i o n W e l l #78, T42N-R78W-17 cbc, Sussex F i e l d , Tensleep "A" U n i t , T o t a l Depth = 8995 f e e t .

Casing S i z e

Wt.

10-3/4" 7"

(#/ft)

32.75 26

Depth S e t

Cement

238'

200 sacks

8995 '

200 s a c k s

Tensleep "B" Unit The Tensleep "B" Unit of Sussex F i e l d covers 1,520 a c r e s of f e d e r a l , s t a t e , and p r i v a t e f e e land.

The Tensleep "B" r e s e r v o i r

c o n s i s t s of 1,092 a c r e s of gray t o w h i t e , d o l o m i t i c , fine-grained sandstone w i t h an average pay t h i c k n e s s of 103 f e e t . Core a n a l y s e s a t two w e l l s i t e s i n d i c a t e d t h a t t h e p e r m e a b i l i t y and p o r o s i t y of t h e Tensleep sand i n t h i s a r e a were h i g h l y v a r i a b l e . P o r o s i t y e s t i m a t e s ranged from 0.4 t o 18.6 percent and p e r m e a b i l i t y measurements v a r i e d between 0.01 t o 271 m i l l i d a r c i e s .

The two w e l l s

a r e l o c a t e d w i t h i n t h e same q u a r t e r - q u a r t e r of S e c t i o n 1 5 , Township 42 North, 3ange 78 West. S t r u c t u r a l l y , t h e r e i s a major east-west tending f a u l t which c u t s a c r o s s t h e s o u t h end of t h e r e s e r v o i r .

The o r i g i n a l producing mechanism

of t h e r e s e r v o i r was f l u i d and rock expansion. i n 1958, t o s t i m u l a t e d e c l i n i n g o i l production.

Water i n j e c t i o n began It was expected t h a t

t h e p e r i p h e r a l l y p a t t e r n e d waterflood p r o j e c t would provide t h e s t i m u l u s f o r t h e recovery of 23.8 p e r c e n t of t h e o r i g i n a l o i l i n place. A s of December, 1979, eleven of t h e twelve i n j e c t i o n w e l l s were still actively injecting.

A cumulative t o t a l of 116,953,612 b a r r e l s

9 (4.9121 x 10 g a l l o n s ) of water from t h e Madison Limestone had been r e s e r v o i r a t t h a t time.

i n j e c t e d i n t o t h e Tensleep "B"

Casing Record:

I n j e c t i o n Well # l 8 7 , T42N-R78W-15 cad, Sussex F i e l d , Tensleep "B" U n i t , T o t a l Depth = 9439 f e e t .

Casing S i z e

Wt.

(#/ft)

Hale S i z e

54 5

13-3/8"

17-1/2"

Depth S e t 310 '

Cement 375 sacks "G"

C1.

23,26

8-31/32''

9439 '

700 sacks C 1 . 'IG"

Lakota "B" Unit The Lakota "B"

r e s e r v o i r i s a Lower Cretaceous sandstone found a t

an average depth of 7,875 f e e t .

The r e s e r v o i r i s a f a u l t e d , a n t i c l i n a l

s t r u c t u r e bound on t h e s o u t h by a major normal s e a l i n g f a u l t and on t h e o t h e r t h r e e s i d e s by an oil-water c o n t a c t .

The Lakota sand i n t h i s a r e a

has a g r o s s t h i c k n e s s of 50 f e e t and t h e r e s e r v o i r has a maximum c l o s u r e of 250 f e e t . Primary production began i n 1949, and r e s e r v o i r energy h a s been provided by a combination of f l u i d expansion, s o l u t i o n gas d r i v e , and n a t u r a l water encroachment.

Secondary recovery of o i l was i n i t i a t e d i n

1970, and was expected t o provide an estimated 290,000 b a r r e l s of additional o i l .

A cumulative t o t a l of 1,920,833 b a r r e l s (80,674,986

g a l l o n s ) of water had been i n j e c t e d p r i o r t o J u l y , 1976, when both

i n j e c t i o n w e l l s were temporarily shut-in.

Water used i n t h e secondary

recovery p r o j e c t was produced from t h e Madison Limestone and obtained from t h e Shiloh Water System.

I n j e c t i o n W e l l 1/22, T42N-R78W-22 abd, Sussex F i e l d , Lakota "B" U n i t , T o t a l Depth = 7400 f e e t .

Casing Record:

Casing S i z e

Wt.

10-314"

(#/ft)

Depth S e t

32.75

7"

23

Cement

310'

160 s a c k s

7400 '

300 sacks

West Sussex F i e l d (17,100,613 b b l s o i l , 8,378,739 MCF gas; 1951-79) Unit

Shannon "A-B"

The Shannon "A-B"

Unit covers an a r e a of 1,832.87 a c r e s , of which

1,652.87 a c r e s a r e f e d e r a l l y owned and 180 a c r e s a r e p r i v a t e l y owned f e e lands.

The Shannon r e s e r v o i r i s found a t an average depth of

approximately 3,180 f e e t i n t h i s a r e a .

The r e s e r v o i r c o n t a i n s 1,738

a c r e s of l i g h t gray, g l a u c o n i t i c , w e l l - s o r t e d , sandstone.

coarse-grained,

friable

The average t h i c k n e s s of t h e pay zone i s 23.8 f e e t .

A

complex system of seven s e p a r a t e f a u l t b l o c k s , t h r e e of which have s m a l l gas caps, make up t h e Shannon "A-B"

reservoir.

Water i n j e c t i o n i n t o t h e seven f a u l t blocks began i n 1955.

The

p r o j e c t was expanded t o 36 w e l l s , of which 16 were a c t i v e l y i n j e c t i n g a s of December, 1979.

Cumulative water i n j e c t i o n t o t h a t p o i n t was

9 51,408,144 b a r r e l s (2.1591 x 10 g a l l o n s ) .

Fresh water i s s u p p l i e d from

t h e Madison Limestone through t h e Shiloh Water Supply Line. Casing Record:

I n j e c t i o n Well #12, T42N-R79W-5 dcb, West Sussex F i e l d , Shannon "A-B" U n i t , T o t a l Depth = 3159 f e e t .

Casing S i z e

Wt.

(Hft)

Make

Depth S e t

Cement

9-5/8"

29

Armco

170'

150 sacks

4-1/2"

9.5

3159 '

200 sacks with g e l

5-55

Table Rock F i e l d (1,830,325 b b l s o i l , 227,062,857 MCF gas; 1946-79) Table Rock Unit The Table Rock Unit i s t h e s i t e of a f u t u r e s a l t water d i s p o s a l s i t e i n S e c t i o n 35, Township 19 North, Range 98 West, Sweetwater County. Texaco, I n c . ,

i s t h e o p e r a t o r of a d i s p o s a l w e l l t h a t h a s been d r i l l e d

and prepared f o r i n j e c t i o n i n t o t h e Ericson Formation of t h e Upper Cretaceous Mesaverde Group.

The w e l l i s p e r f o r a t e d a t a d e p t h of

6,583 f e e t . Teapot F i e l d - Naval Petroleum Reserve #3 (9,924,277 b b l s o i l , 2,622,429 MCF g a s ; 1922-79) Teapot Dome Unit A f u l l s c a l e water i n j e c t i o n p r o j e c t was r e c e n t l y p u t i n t o o p e r a t i o n a t t h e Teapot Dome Unit of Naval Petroleum Reserve #3, i n S e c t i o n s 20 and 21, Township 39 North, Range 78 West, Natrona County.

Ten w e l l s began

i n j e c t i o n i n t o t h e second Wall Creek sand d u r i n g t h e e a r l y months of 1979. Water f o r t h e f l o o d i s obtained from Madison Limestone supply w e l l #17

7 A s of J u l y , 1979, 306,174 b a r r e l s (1.2859 x 10 g a l l o n s ) of water had been i n j e c t e d through t h e t e n w e l l s a t average p r e s s u r e s between 100 and 800 p s i .

Tholson F i e l d (1,802,808 b b l s o i l , 5,384 MCF g a s ; 1969-79) Minnelusa "A"

Sand Unit

The Minnelusa "A"

Sand Unit of Tholson F i e l d i s l o c a t e d i n Township

49 North, Range 70 West, Campbell County. Minnelusa "A"

Water i n j e c t i o n t o t h e

sand began i n 1973, through one w e l l i n S e c t i o n 2.

second w e l l was added i n 1977, a l s o i n S e c t i o n 2.

A

Both i n j e c t o r s a r e

p e r f o r a t e d a t a depth of about 8,750 f e e t .

Cumulative i n j e c t i o n t o

7 December, 1979, was 1,927,157 b a r r e l s (8.094 x 10 g a l l o n s ) of water from t h e Fox H i l l s Sandstone.

Average i n j e c t i o n p r e s s u r e s a t t h e two

w e l l s have ranged from a minimum of 100 p s i t o a maximum of 2,700 p s i .

Timber Creek F i e l d (12,015,888 b b l s o i l , 263,961 MCF gas; 1958-79) Timber Creek F i e l d i s l o c a t e d i n township 49 n o r t h , range 70 w e s t , Campbell County.

It i s t h e s i t e of f i v e s a l t water d i s p o s a l systems

a t f i v e s e p a r a t e u n i t s of t h e f i e l d .

Four of t h e systems--the

Federal

311 Campbell U n i t , Lesueur U n i t , Lesueur 'IS" U n i t , and t h e V. H. Wolff Unit systems--are

completed i n t h e Minnelusa Formation.

The d i s p o s a l

w e l l a t t h e F. E. Cook Unit is p e r f o r a t e d i n t h e Dakota sand a t a depth of 7,800 f e e t . The f i r s t system t o be operated a t Timber Creek was a s i n g l e d i s p o s a l w e l l a t t h e V. H. Wolff Unit.

I n j e c t i o n began i n 1967, and

continued u n t i l December, 1973, when t h e w e l l was temporarily shut-in. The depth of p e r f o r a t i o n i s 9,178 f e e t .

Cumulative i n j e c t i o n through

7 t h e w e l l was 319,462 b a r r e l s (1.3417 x 10 g a l l o n s ) of b r i n e from p r o d u c t i o n w e l l s a t Timber Creek F i e l d .

The maximum average i n j e c t i o n

p r e s s u r e was 638 p s i w h i l e t h e w e l l was o p e r a t i n g . The d i s p o s a l w e l l a t t h e F e d e r a l 311 Campbell Unit a l s o began o p e r a t i n g i n 1967; however, t h a t w e l l i s s t i l l a c t i v e l y i n j e c t i n g .

The

d e p t h a t which t h e produced b r i n e i s being i n j e c t e d i s 9,218 f e e t . The w e l l i s l o c a t e d i n S e c t i o n 8 of t h e p r e v i o u s l y mentioned township and range.

Cumulative i n j e c t i o n , a s of January, 1980, was 278,290

7 b a r r e l s (1.1688 x 10 g a l l o n s ) of s a l t w a t e r . S a l t water d i s p o s a l a t t h e Lesueur Unit s t a r t e d i n 1969, through an i n j e c t i o n w e l l i n S e c t i o n 18.

The w e l l i s p e r f o r a t e d a t 9,227 f e e t

i n t h e Minnelusa Formation.

The most r e c e n t i n j e c t i o n r e p o r t i n d i c a t e s

7 t h a t a cumulative volume of 679,773 b a r r e l s (2.855 x 10 g a l l o n s ) of produced b r i n e had been i n j e c t e d a s of June, 1980.

Average i n j e c t i o n

p r e s s u r e s ranged from 1,600 t o 2,289 p s i . The d i s p o s a l system a t t h e Lesueur "S" Unit i s t h e only two w e l l opexation a t Timber Creek. 1972.

I n j e c t i o n of produced b r i n e s t a r t e d i n

Both w e l l s a r e l o c a t e d i n S e c t i o n 17.

Cumulative i n j e c t i o n

through both w e l l s , a s of June, 1980, was 439,883 b a r r e l s (1.8475 x 7 10 g a l l o n s ) of water. I n 1978, a s i n g l e w e l l d i s p o s a l system was added a t t h e F. E. Cook Unit of Timber Creek F i e l d .

The w e l l i s l o c a t e d i n S e c t i o n 7 ,

Township 49 North, Range 70 Nest, and i s p e r f o r a t e d a t a depth of 7,800 f e e t i n t h e Dakota sand.

Cumulative i n j e c t i o n f o r 1978 and 1979

combined was 10,940 b a r r e l s (459,480 g a l l o n s ) of produced s a l t water from w e l l s a t Timber Creek.

Average i n j e c t i o n p r e s s u r e s have ranged

between 400 and 1,000 p s i .

Casing Record:

S a l t Water Disposal W e l l #2, T49N-R70W-8 d c , Timber Creek F i e l d , F e d e r a l 311 Campbell U n i t , T o t a l Depth = 9423 f e e t .

Casing S i z e 5-1/2" Casing Record:

Wt.

(Wt)

15.5,17

Depth S e t

Cement

9423'

400 sacks

S a l t Water Disposal Well # 5 , T49N-R70W-18 d a , Timber Creek F i e l d , Lesuer U n i t , T o t a l Depth = 9412 f e e t .

Casing S i z e

Wt.

(#/ft)

Depth S e t

Cement

10-314"

40.5

305 '

250 sacks

5-1/2"

17

9412 '

300 s a c k s

Tip Top F i e l d (4,251,584 b b l s o i l , 270,414,250 MCF g a s ; 1928-79) Shallow Unit Tip Top F i e l d was discovered i n 1928, when a p r o d u c t i v e w e l l was completed i n t h e Almy r e s e r v o i r of t h e Wasatch Formation.

It wasn't

u n t i l 1974, t h a t a water i n j e c t i o n p r o j e c t was p u t i n t o o p e r a t i o n a t t h e The u n i t is l o c a t e d i n Township 28 North, Range

Tip Top Shallow Unit.

118 West, S u b l e t t e County. I n j e c t i o n t o t h e Almy r e s e r v o i r s t a r t e d through f i v e w e l l s s u p p l i e d w i t h water from t h r e e Almy s o u r c e w e l l s , a s w e l l a s Tip Top F i e l d producing w e l l s . and 1,192 f e e t .

The r e s e r v o i r is found a t depths between 885

A l l of t h e i n j e c t i o n w e l l s were a c t i v e d u r i n g t h e l a s t

s i x months of 1979.

Cumulative i n j e c t i o n t o December, 1979, was

3,436,703 b a r r e l s (1.4434 x

lo8

g a l l o n s ) of w a t e r .

Maximum average

i n j e c t i o n p r e s s u r e s have n o t exceeded 1,700 p s i . A s a l t water d i s p o s a l system, c o n s i s t i n g of two w e l l s completed i n t h e Almy sand, was p u t i n t o o p e r a t i o n by Mountain Fuel Supply Company i n 1971.

The w e l l s a r e l o c a t e d i n S e c t i o n s 28 and 33, Township

28 North, Range 113 West, S u b l e t t e County.

Cumulative i n j e c t i o n through

8 b o t h w e l l s was 9,762,349 b a r r e l s (4.1002 x 10 g a l l o n s ) a s of June, 1980.

I n j e c t i o n p r e s s u r e s have been v e r y low, averaging 50 p s i .

Both

w e l l s were a c t i v e d u r i n g t h e f i r s t s i x months of 1980. Casing Record:

I n j e c t i o n Well #57, T28N-R113W-21, Tip Top F i e l d , Tip Top Shallow U n i t , T o t a l Depth = 1288 f e e t .

Casing S i z e

Wt.

(#/ft)

Amount

Perforations

8-5/8"

24

204'

-

4-1/2"

14,15.5

1270'

1011-1017' 1070-1074' 1151-1169'

Purpose Surf a c e Injection

S a l t Water D i s p o s a l W e l l #68, T28N-R113W-28 c d , Tip Top F i e l d , T i p Top Shallow U n i t , T o t a l Depth = 1390 f e e t .

Casing Record:

Casing S i z e

Wt.

( m t )

Depth S e t

8-5/8"

24

236'

5-1/2"

14,15.5

1390 '

North T i s d a l e F i e l d (2,814,316 b b l s o i l , 44,724 MCF g a s ; 1952-79) An e l e v e n w e l l t e r t i a r y o i l r e c o v e r y p r o j e c t h a s been i n o p e r a t i o n

a t North T i s d a l e F i e l d s i n c e 1963.

The p r o j e c t i s o p e r a t e d by C o n t i n e n t a l

O i l Company and i s l o c a t e d i n Township 4 1 North, Range 8 1 West, Johnson

County. stone.

A h o t w a t e r s o l u t i o n i s i n j e c t e d t o t h e J u r a s s i c C u r t i s SandF u r t h e r d e t a i l s on t h e p r o j e c t were u n a v a i l a b l e from O i l and

Gas Commission f i l e s .

Tomcat Creek F i e l d (272,479 b b l s o i l ; 1959-79) F a l l River U n i t Tomcat Creek F i e l d i s l o c a t e d i n Township 49 Worth, Range 65 west, Crook County, and was d i s c o v e r e d i n 1959, when o i l was i n i t i a l l y produced from t h e F a l l R i v e r Sandstone, I n 1976, Grace Petroleum Company i n i t i a t e d a w a t e r i n j e c t i o n p r o j e c t a t t h e F a l l River U n i t of Tomcat Creek F i e l d .

The w a t e r f l o o d

i n c l u d e s f o u r w e l l s , p e r f o r a t e d a t d e p t h s r a n g i n g from 350 t o 430 f e e t i n t h e lower F a l l R i v e r s a n d ,

Water f o r t h e p r o j e c t i s provided by a

supply w e l l , a l s o completed i n t h e F a l l River Sandstone a t a d e p t h of 416 f e e t . A l l of t h e w e l l s were a c t i v e l y i n j e c t i n g d u r i n g t h e l a s t s i x months of 1979, and cumulative i n j e c t i o n a t t h e end of t h a t p e r i o d t o t a l e d

7

758,794 b a r r e l s (3.1869 x 1 0

g a l l o n s ) of w a t e r i n j e c t e d s i n c e t h e

p r o j e c t s t a r t e d i n 1976.

Average i n j e c t i o n p r e s s u r e s have ranged from

150 t o 425 p s i .

T o r c h l i g h t F i e l d (14,177,454 b b l s o i l , 3,888,449 MCF gas; 1935-79) Madison Unit The Madison Unit of T o r c h l i g h t F i e l d i s l o c a t e d i n Township 5 1 North, Ranges 92 and 93 West, Big Horn County.

Structurally, the f i e l d

i s s i t u a t e d a t o p an e l l i p t i c a l dome i n t h e c e n t e r of Township 5 1 North, on t h e l i n e between t h e two ranges. The Madison Limestone r e s e r v o i r underlying t h e u n i t , covers 685 a c r e s w i t h an average pay zone t h i c k n e s s of 67 f e e t .

Core a n a l y s e s

i n d i c a t e an average r e s e r v o i r p o r o s i t y and p e r m e a b i l i t y of 21 p e r c e n t and 33.5 m i l l i d a r c i e s , r e s p e c t i v e l y . I n September, 1962, a one w e l l gas i n j e c t i o n p r o j e c t was s t a r t e d . Then, i n May, 1963, w i t h t h e approval of t h e O i l and Gas Conservation Commission, t h e gas i n j e c t i o n p r o j e c t expanded t o a f u l l s c a l e water and gas i n j e c t i o n program.

Water and gas f o r t h e p r o j e c t s were obtained

from t h e Madison and Phosphoria formations, r e s p e c t i v e l y .

A t t h e time

t h i s r e p o r t was compiled, both p r o j e c t s had been d i s c o n t i n u e d . Cumulative i n j e c t i o n t o t a l s f o r t h e waterflood were 8,964,832 b a r r e l s 8 (3.7652 x 10 g a l l o n s ) of water through n i n e w e l l s .

Average i n j e c t i o n

p r e s s u r e s d i d n o t exceed 2,000 p s i w h i l e t h e w e l l s were i n o p e r a t i o n .

Casing Record:

I n j e c t i o n Well #30, T51N-R93W-24 cba, T o r c h l i g h t F i e l d , Madison U n i t , T o t a l Depth = 3903 f e e t .

Casing S i z e

Wt.

10-3/4" 7"

(#/ft)

32.75 20

Hole S i z e

Depth S e t

Cement

15"

661'

700 sacks

9"

3902'

425 sacks (50-50 pozmix)

Tensleep Unit A t e r t i a r y recovery p r o j e c t , operated by Amoco Production Company,

began o p e r a t i o n s a t t h e Tensleep Unit of T o r c h l i g h t F i e l d i n 1976. The Tensleep r e s e r v o i r i n t h i s a r e a covers 291 a c r e s w i t h an average pay zone t h i c k n e s s of 23 f e e t . mechanism was a l i m i t e d water d r i v e .

The o r i g i n a l r e s e r v o i r producing I n 1957, a water i n j e c t i o n p r o j e c t

began a t t h e Tensleep Unit w i t h t h e purpose of maintaining Tensleep reservoir pressure.

The waterflood was expanded i n 1958, and then

stopped i n J u l y , 1967. b a r r e l s (1.8649 x LO

8

Cumulative i n j e c t i o n t o t h a t d a t e , was 4,440,344 g a l l o n s ) of water.

The t e r t i a r y recovery p r o j e c t i n c l u d e s f i v e i n j e c t i o n w e l l s which have been i n j e c t i n g a w a t e r / m i c e l l a r s o l u t i o n i n t o t h e Tensleep reservoir.

One of t h e w e l l s has been shut-in.

F u r t h e r d e t a i l s on t h e

p r o j e c t were not a v a i l a b l e a t t h e time of t h i s w r i t i n g . Torrington F i e l d (464,495 b b l s o i l ; 1955-79) Van Mark Unit The Van Mark Unit of t h e Torrington F i e l d has, s i n c e 1975, been t h e s i t e i f a secondary o i l recovery water i n j e c t i o n p r o j e c t completed i n t h e "J1' sand of t h e Muddy Sandstone.

The f i e l d i s l o c a t e d i n Townships

23 and 24 North, Range 6 1 West, Goshen County, about t h r e e m i l e s southwest of t h e c i t y of Torrington. The p r o j e c t began a s a s i n g l e w e l l p i l o t s t u d y , using water provided by shallow supply w e l l s , and was expanded t o t h r e e i n j e c t i o n w e l l s i n 1977, and t o s i x w e l l s i n 1978.

The depth t o t h e Muddy "J"

sand r e s e r v o i r is about 6,900 f e e t i n t h e Torrington F i e l d a r e a . of October, 1979, cumulative i n j e c t i o n was 362,012 b a r r e l s (1.5204

As

7 x 10 g a l l o n s ) of water.

Only one of t h e w e l l s was a c t i v e l y i n j e c t i n g

during t h e l a s t r e p o r t e d p e r i o d .

The remainder had been shut-in.

Reported i n j e c t i o n p r e s s u r e s , averaged a t e a c h ' w e l l f o r each s i x month p e r i o d , ranged from 2,900 t o 4,450 p s i and a r e considered extremely h i g h f o r t h e t y p e of casing used i n t h e w e l l s .

A casing

schedule r e p r e s e n t a t i v e of the i n j e c t i o n w e l l s i s given below.

I n j e c t i o n Well bW-5, T24N-R61W-33 c b ( b c ) , Torrington F i e l d , Van Mark U n i t , T o t a l Depth = 7003 f e e t .

Casing Record:

Casing S i z e

Wt.

8-5/8"

(#/ft) 24

5-1/2"

17,15.5

Cement

Purpose

Hole S i z e

Depth S e t

12-1/4l1

415'

250 sacks

Surface

7-7/8"

7002'

150 sacks

Injection

U t e F i e l d (8,890,789 b b l s o i l , 22,156,306 MCF gas; 1967-79) Muddy Sand Unit Water i n j e c t i o n a t Ute F i e l d began i n 1973, a t t h e Muddy Sand U n i t , l o c a t e d i n t h e n o r t h e r n p o r t i o n of Township 57 North, Range 72 West, and t h e southern p o r t i o n of Township 58 North, Range 72 West, Campbell County.

The i n j e c t e d formation i s t h e Muddy Sandstone which

i s encountered a t depths ranging from 6,237 t o 6,534 f e e t i n t h e Ute Field area.

The average p o r o s i t y of t h e Muddy r e s e r v o i r i s between

16.8 and 21.3 p e r c e n t , based on c o r e samples from t h r e e of t h e i n j e c t i o n wells.

Water f o r t h e f l o o d i s obtained from t h e Fox H i l l s Sandstone.

By 1976, t h e waterflood p r o j e c t included 1 3 w e l l s , all of which

were a c t i v e l y i n j e c t i n g during 1979.

Cumulative i n j e c t i o n f o r t h e

8 p r o j e c t , a s of December, 1979, was 20,419,997 b a r r e l s (8.5764 x 10 g a l l o n s ) of water.

Average i n j e c t i o n p r e s s u r e s ranged from a minimum

of 75 p s i t o a maximum of 4,134 p s i .

Casing Record:

Casing S i z e

I n j e c t i o n W e l l # ~ r .3-11, T57N-R72W-10 b a y U t e F i e l d , Muddy Sand U n i t , T o t a l Depth = 6,416 f e e t . Wt.

(#If t )

8-5 /8"

24

5-1/2"

15.5

Hole S i z e

Cement

Depth S e t

Purpose

12-1/4"

163 '

150 s a c k s

Surface

7-7 /8"

6416'

200 s a c k s

Injection

Olmstead U n i t The i n j e c t i o n of w a t e r t o t h e Muddy sand r e s e r v o i r u n d e r l y i n g t h e Olmstead U n i t of U t e F i e l d , s t a r t e d i n 1975, through t h r e e w e l l s .

The

u n i t a r e a i n c l u d e s p a r t s of S e c t i o n s , 1, 2, and 1 2 , Township 57 North, Range 72 West, Campbell County. f l o o d i n 1979.

A f o u r t h w e l l w a s added t o t h e water-

Water f o r t h e p r o j e c t i s provided by a s u p p l y w e l l

i n t h e Fox H i l l s Sandstone. 7 A s of December, 1979, 1,915,048 b a r r e l s (8.0432 x 1 0 g a l l o n s ) of w a t e r had been i n j e c t e d through a l l f o u r w e l l s .

Injection pressures

a t e a c h w e l l , averaged over each s i x month p e r i o d of i n j e c t i o n , ranged from 433 t o 3,025 p s i .

Casing Record:

I n j e c t i o n W e l l #7-1, T57N-R72W-1 bd, U t e F i e l d , Olmstead U n i t , T o t a l Depth = 6,414 f e e t .

Casing S i z e

Wt.

8-518" 5-1/2"

( m t ) 24

15.5,17

Hole S i z e

Depth S e t

Cement

12-114"

150 '

190 s a c k s

7-718"

6414 '

300 s a c k s

Wagonspoke F i e l d (1,025,172 b b l s o i l , 40,302 MCF g a s ; 1972-79) Ashmar-Federal U n i t Wagonspoke F i e l d i s l o c a t e d i n Township 52 North, Range 69 West, Campbell County.

O i l was d i s c o v e r e d a t Wagonspoke i n 1972, when a

p r o d u c t i v e w e l l was completed i n t h e Minnelusa Formation a t a d e p t h of about 7,300 f e e t .

I n 1978, water i n j e c t i o n t o t h e Minnelusa r e s e r v o i r was s t a r t e d i n o r d e r t o enhance r e s e r v o i r p r e s s u r e and i n c r e a s e production.

The

Fox H i l l s Sandstone was tapped t o supply water f o r t h e i n j e c t i o n project.

I n t h e two y e a r s t h a t t h e s i n g l e w e l l waterflood h a s been

7 o p e r a t i n g , a cumulative volume of 463,066 b a r r e l s (1.9448 x 1 0 g a l l o n s ) of water have been i n j e c t e d a t average p r e s s u r e s ranging from 2,100 t o 2,466 p s i .

Casing Record:

I n j e c t i o n Well #5-3, T52N-R69W-3 bcb, Wagonspoke F i e l d , Ashmar-Federal U n i t , T o t a l Depth = 7460 f e e t .

Casing S i z e

Wt.

(#/ft)

Hole S i z e

Depth S e t

8-518"

24

12-114''

180'

5-112"

15.5,17

7-7/8"

7400'

Cement t o surface 350 sacks

Wallace F i e l d (4,394,284 b b l s o i l , 6,843 MCF gas; 1966-79) Minnelusa Unit A p i l o t water i n j e c t i o n s t u d y was i n i t i a t e d a t t h e Minnelusa Unit

of Wallace F i e l d i n 1970, by A t l a n t i c R i c h f i e l d Company.

The Minnelusa

Unit i s l o c a t e d i n t h e extreme n o r t h e r n p a r t of Township 5 1 North, Range 70 West, and t h e extreme southern p a r t of Township 52 North, Range 70 West, Campbell County.

Gradual expansion of t h e Minnelusa

r e s e r v o i r waterflood has increased t h e number of i n j e c t i o n w e l l s t o nine.

A l l of t h e w e l l s a r e p e r f o r a t e d i n t h e Minnelusa a t depths

ranging from 7,800 t o 8,040 f e e t . Cumulative i n j e c t i o n t o t h e Minnelusa r e s e r v o i r , through December, 8 1979, t o t a l e d 16,034,493 b a r r e l s (6.7345 x 10 g a l l o n s ) of water from t h e Fox H i l l s Sandstone water supply w e l l #1. Average i n j e c t i o n p r e s s u r e s have f l u c t u a t e d between 1,100 and 2,750 p s i s i n c e t h e p r o j e c t

A l l of t h e w e l l s were a c t i v e l y i n j e c t i n g during t h e

s t a r t e d i n 1970.

second h a l f of 1979. I n j e c t i o n Well #W-7, T52N-R70W-26 dcc, Wallace F i e l d , Minnelusa Unit, T o t a l Depth = 8049 f e e t .

Casing Record:

Casing S i z e

(#/ft)

Wt.

Hole S i z e

24

8-5/8"

17,20

5-1/2"

Depth S e t

Cement

Purpose

12-1/4"

204 '

160 sacks

Surface

7-7/8"

8050 '

350 sacks

Injection

Warm Springs F i e l d (1,519,328 b b l s o i l ; 1917-79) West Freudenthal Unit Warm Springs F i e l d i s l o c a t e d i n Township 43 North, Ranges 93 and 94 West, Hot Springs County, and was discovered i n 1917.

A water

i n j e c t i o n p r o j e c t was i n i t i a t e d i n 1975, w i t h Cork Petroleum Company a s operator.

A s of December, 1979, t h e p r o j e c t c o n s i s t e d of s i x w e l l s

p e r f o r a t e d i n t h e Phosphoria Formation a t a depth of approximately 900 feet.

Four of t h e w e l l s were s t i l l on a c t i v e s t a t u s , one had been

temporarily shut-in and t h e o t h e r w a s permanently shut-in.

7

i n j e c t i o n t o t h a t d a t e was 2,199,800 b a r r e l s (9.2391 x 10 water from t h e Darwin and Phosphoria formations.

Cumulative g a l l o n s ) of

Injection pressures,

averaged over each six-month period a t each w e l l , were r e l a t i v e l y low, ranging from 150 t o 650 p s i .

Casing Record: Casing S i z e

I n j e c t i o n Well #38, T43N-R94W-35 cbd, West Warm Springs F i e l d , Freudenthal Unit, T o t a l Depth = 870 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

8-5/8"

24

10"

30'

10 sacks

5-1/2"

14

8"

868 '

100 sacks

Purpose Surface Injection

Well Draw F i e l d (17,027,774 b b l s o i l , 33,622,537 MCF gas; 1973-79) Well Draw F i e l d covers a l a r g e a r e a i n Townships 33 t o 36 North, Ranges 67 t o 70 West, Converse County.

The f i e l d was discovered i n

1973, and has expanded t o i n c l u d e 310 producing w e l l s , making i t one of t h e most p r o d u c t i v e f i e l d s i n t h e s t a t e after only s i x y e a r s of development. There a r e t h r e e i n j e c t i o n w e l l s a t Well Draw F i e l d , a l l of them s a l t water d i s p o s a l w e l l s , t h a t s t a r t e d o p e r a t i n g i n 1977.

Disposal

w e l l s a r e l o c a t e d i n t h e #1Lebar U n i t , t h e Williams Unit and t h e Hoffman Unit.

Wells a t t h e # 1 Lebar and Williams u n i t s a r e completed

i n t h e Lewis Shale a t 5,840 and 5,338 f e e t , r e s p e c t i v e l y .

Cumulative

i n j e c t i o n d a t a were a v a i l a b l e f o r t h e W i l l i a m s Unit w e l l o n l y , and i n d i c a t e d t h a t 10,733 b a r r e l s (450,786 g a l l o n s ) of produced b r i n e had been i n j e c t e d between 197.7, and February, 1980. The d i s p o s a l w e l l a t t h e Hoffman Unit i s l o c a t e d i n s e c t i o n 30, Township 34 North, Range 68 West, Converse County.

It i s completed

i n t h e Teapot Sandstone a t a depth of 7,003 f e e t .

A s of June, 1978,

68,699 b a r r e l s (2,885,358 g a l l o n s ) of produced s a l t water had been i n j e c t e d s i n c e t h e s t a r t of t h e o p e r a t i o n .

Casing Record:

S a l t Water Disposal Well #4, T34N-R68W-30 a a , Well Draw F i e l d , Hoffman U n i t , T o t a l Depth = 7176 f e e t .

Casing S i z e

Wt.

(#/ft)

8-5 /8"

24

5-1/2"

15.5

Hole S i z e

Depth S e t

Cement

12-1/4"

316 '

196 sacks

7-7 /8"

7178'

175 sacks

Wertz F i e l d (77,262,481 b b l s o i l , 22,299,990 MCF gas; 1921-79) Wertz Unit Wertz F i e l d i s s i t u a t e d on an e l l i p t i c a l dome i n Township 26 North, Ranges 89 and 90 West, Sweetwater and Carbon c o u n t i e s . was discovered i n t h e Dakota sand.

I n 1920, gas

L a t e r d i s c o v e r i e s of o i l and/or gas

were made i n t h e Mowry Shale, t h e F r o n t i e r Formation, t h e Lakota Sands t o n e , t h e Sundance Formation, t h e Tensleep Sandstone, t h e Amsden Formation, t h e Madison Limestone, and a sand of Cambrian age. I n 1941, a gas i n j e c t i o n p r e s s u r e maintenance p r o j e c t was s t a r t e d t o supplement t h e n a t u r a l water d r i v e of t h e Tensleep r e s e r v o i r .

Gas

produced w i t h o i l from t h e Tensleep and some gas from t h e upper sands i s i n j e c t e d i n t o one w e l l on t h e c r e s t of t h e Wertz F i e l d dome.

The

b e n e f i t s of t h i s g a s i n j e c t i o n p r o j e c t were l i s t e d i n t h e waterflood s t u d y done by Biggs and Koch (1970).

They a r e (1) t h e Tensleep g a s ,

which h a s low f u e l v a l u e (52 p e r c e n t CO ), was p u t t o good u s e i n s t e a d 2 of being wasted; ( 2 ) t h e flowing l i f e of t h e w e l l s was prolonged; and

( 3 ) i n c r e a s e d r a t e of recovery has been p o s s i b l e without damage t o t h e reservoir.

The program was begun b e f o r e bottom h o l e p r e s s u r e s had

d e c l i n e d below l e v e l s necessary f o r flowing w e l l s . Water i n j e c t i o n t o t h e Tensleep r e s e r v o i r s t a r t e d i n 1954, t o supplement t h e r e s e r v o i r p r e s s u r e provided by gas i n j e c t i o n and water i n f l u x from t h e s o u t h e a s t .

The Tensleep r e s e r v o i r covers 1,150

a c r e s w i t h an average pay zone t h i c k n e s s of 150 f e e t .

By t h e end of

1978, t h e r e were 11 w e l l s a c t i v e l y i n j e c t i n g t o t h e r e s e r v o i r .

Three

of t h e w e l l s a r e d u a l l y completed i n t h e Tensleep and Madison o r Amsden reservoirs.

Cumulative i n j e c t i o n of produced water from t h e Madison Limestone through December, 1979, was 62,850,190 b a r r e l s (2.6397 x 109 g a l l o n s ) of water and 45,196,540 m i l l i o n cubic f e e t of n a t u r a l gas.

Average i n j e c -

t i o n p r e s s u r e s a t t h e waterflood p r o j e c t have n o t exceeded 2,100 p s i . Gas i n j e c t i o n p r e s s u r e s have n o t exceeded 1,426 p s i .

West Wertz Unit

The West Wertz Unit of Wertz F i e l d became t h e s i t e of a water i n j e c t i o n p r o j e c t i n 1968, w i t h t h e i n i t i a l i n j e c t i o n of water from t h e Madison Limestone t o t h e Tensleep r e s e r v o i r , a t a depth of 5,880 feet. Cumulative i n j e c t i o n , a s of December, 1979, was 5,521,113 b a r r e l s 8 (2.3189 x 1 0 g a l l o n s ) of water.

Average i n j e c t i o n p r e s s u r e s have

ranged from 1,183 t o 1,700 p s i .

Casing Record:

I n j e c t i o n Well 84, T26N-R90W-1 bb(cd), Wertz F i e l d , West Wertz U n i t , T o t a l Depth = 7388 f e e t .

Casing S i z e

Wt.

13-3/8"

(#/ft) 48

Hole S i z e

Depth ,Set

17-1/2"

495 ' 7375'

Cement 500 sacks 600 sacks (50-50 pozmix)

Whisler F i e l d (337,798 b b l s o i l , 6,175 MCF gas; 1967-79) Minnelusa Unit Water i n j e c t i o n t o t h e Minnelusa Formation underlying t h e Minnelusa Unit of Whisler F i e l d , s t a r t e d i n 1975, w i t h P r e n a l t a Corporation a s u n i t operator.

I n 1976, a second w e l l was added t o t h e p r o j e c t .

The

w e l l s a r e completed a t depths of 8,288 and 8,442 f e e t i n t h e Minnelusa reservoir.

Produced Minnelusa water i s used i n t h e waterflood.

Cumulative i n j e c t i o n a s of December, 1979, was 655,751 b a r r e l s 7 (2.7541 x 1 0 g a l l o n s ) of water. The Minnelusa U n i t of Whisler F i e l d c o v e r s a 320 a c r e a r e a of f e d e r a l and p r i v a t e l a n d .

The r e s e r v o i r a r e a i n c l u d e s 164.3 a c r e s

w i t h a n a v e r a g e pay zone t h i c k n e s s of 1 2 . 1 f e e t .

Average p o r o s i t y

and p e r m e a b i l i t y of t h e r e s e r v o i r a r e 18.6 p e r c e n t and 242.2 m i l l i darcies, respectively.

Casing Record:

Casing S i z e

I n j e c t i o n W e l l #2, T51N-R70W-35 bcd, Whisler F i e l d , Minnelusa U n i t , T o t a l Depth = 8442 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-5/8"

24

12-1/4"

165'

150 s a c k s

Surface

5-1/2"

15.5,17,20

7-7/8"

8420'

450 s a c k s

Injection

W h i t e t a i l F i e l d (5,110,663 b b l s o i l , 1,985,063 MCF g a s ; 1968-79) Muddy Sand U n i t The Muddy Sand U n i t of W h i t e t a i l F i e l d c o v e r s 2,170.8 a c r e s of f e d e r a l , s t a t e , p r i v a t e , and commutized ( j o i n t f e d e r a l and s t a t e ownership) l a n d i n T o m s h i p 56 North, Range 72 West, Campbell County. The f i r s t p r o d u c t i v e w e l l a t W h i t e t a i l F i e l d was completely i n t h e Muddy Sandstone d u r i n g 1968.

The Muddy Sandstone r e s e r v o i r h a s an a v e r a g e

p o r o s i t y and a i r p e r m e a b i l i t y of 22.4 p e r c e n t and 148 m i l l i d a r c i e s , respectively. Water i n j e c t i o n t o t h e Muddy Sandstone began i n 1974, t h r o u g h n i n e w e l l s completed a t d e p t h s r a n g i n g from 6,488 t o 6,888 f e e t .

Cumulative

8 i n j e c t i o n a s of December, 1979, was 15,245,701 b a r r e l s (6.4032 x 1 0 g a l l o n s ) of w a t e r o b t a i n e d from a s u p p l y w e l l i n t h e Fox H i l l s Sandstone.

I n j e c t i o n p r e s s u r e s averaged f o r each w e l l d u r i n g e a c h s i x -

month r e p o r t i n g p e r i o d have ranged from 1 9 t o 2,069 p s i .

Casing Record:

Casing S i z e

I n j e c t i o n Well #109, T56N-R72W-16 adb, W h i t e t a i l F i e l d , Muddy Sand U n i t , T o t a l Depth = 6812 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-518"

24

12-114"

205 '

140 sacks

Surface

5-112"

14,15.5,17

7-718"

6810'

400 sacks

Injection

South Muddy Sand Unit The f i r s t producing w e l l i n t h e South Muddy Unit of W h i t e t a i l F i e l d was completed i n t h e Cretaceous Muddy sand r e s e r v o i r i n 1969. The r e s e r v o i r i s p a r t of a north-south t r e n d i n g segment of a stream channel d e p o s i t , confined on t h e n o r t h , s o u t h and e a s t by a sand pinchout, and on t h e w e s t by an a q u i f e r c o n t a c t .

Some s t r u c t u r a l

t r u n c a t i o n i s e v i d e n t on t h e isopach map b u t , a p p a r e n t l y , has l i t t l e e f f e c t on t h e entrapment of hydrocarbons.

The a r e a l e x t e n t of t h e

r e s e r v o i r , determined from isopach map planimeter r e a d i n g s , i s 276 acres.

The average p o r o s i t y of t h e productive Muddy sand zone i s

16.5 p e r c e n t . The South Muddy Sand Unit p a r t i c i p a t i n g a r e a i n c l u d e s 456.1 a c r e s of f e d e r a l and s t a t e land.

I n j e c t i o n of f r e s h water from t h e Fox

H i l l s Sandstone t o t h e Muddy was i n i t i a t e d i n 1980, through t h r e e

wells.

Cumulative d a t a f o r t h e i n j e c t i o n p r o j e c t was n o t a v a i l a b l e

from t h e f i l e s of t h e O i l and Gas Commission a t t h e time of t h i s w r i t i n g . It h a s been estimated t h a t t h e t o t a l water requirements f o r t h e approxi-

6 mate seven year d u r a t i o n of t h e waterflood w i l l be 1 . 8 x 10 b a r r e l s

7

(7.56 x 1 0

gallons).

Casing Record:

Casing S i z e

I n j e c t i o n Well #16-1, T56N-R72W-16 d d ( c d ) , W h i t e t a i l F i e l d , South Muddy Sand U n i t , T o t a l Depth = 6749 f e e t . Wt.

(#/ft)

Hole S i z e

Depth S e t

Cement

Purpose

8-5/8"

24.5

12-1/4"

250'

200 s a c k s

Surface

5-1/ 2"

15.5

7-7 /8"

6749'

125 s a c k s

Injection

Willow Draw F i e l d (1,488,389 b b l s o i l ; 1972-79) S t a t e 30 Unit The S t a t e 30 Unit of Willow Draw F i e l d i s l o c a t e d i n Township 48 North, Range 103 West, Park County, and i s t h e s i t e of a s i n g l e w e l l s a l t water d i s p o s a l system and a two w e l l a i r i n j e c t i o n p r o j e c t . Both p r o j e c t s a r e l o c a t e d i n s e c t i o n 30 of t h e forementioned area. The d i s p o s a l w e l l was put i n t o o p e r a t i o n i n 1973. i n t h e Madison Limestone.

It i s completed

Cumulative i n j e c t i o n of b r i n e produced from

w e l l s i n t h e Phosphoria Formation t o t a l e d 6,614,865 b a r r e l s 8 (2.7782 x 10 g a l l o n s ) a s of June, 1980.

I n j e c t i o n p r e s s u r e s have

averaged 150 p s i d u r i n g t h e p r o j e c t ' s l i f e t i m e . The a i r i n j e c t i o n p r o j e c t s t a r t e d i n 1975.

Both i n j e c t o r s a r e

completed i n t h e Dinwoody and Phosphoria formations a t a d e p t h of about 4,250 f e e t .

Cumulative i n j e c t i o n b e t w e e n I g 7 5 , a n d December,

1979, was 151,822 m i l l i o n cubic f e e t of a i r through both w e l l s . The average p r e s s u r e a t which t h e a i r i s i n j e c t e d has ranged from 435 t o 651 p s i . Wind Creek F i e l d (373,263 b b l s o i l ; 1958-79) Wind Creek Unit A s i n g l e w e l l s a l t water d i s p o s a l system, operated by Olds O i l

Company, s t a r t e d i n j e c t i o n i n 1972.

Produced b r i n e i s i n j i x t e d t o

t h e Lower Cretaceous B u t l e r sand a t i n j e c t i o n p r e s s u r e s t h a t have averaged between 410 and 550 p s i s i n c e t h e s t a r t of t h e p r o j e c t .

The

w e l l i s l o c a t e d i n S e c t i o n 23, Township 49 North, Range 66 West, Crook

County.

Cumulative i n j e c t i o n through June, 1980, was 7,328,551

8 b a r r e l s (3.078 x 10 g a l l o n s ) of s a l t water. Winkleman D o m e F i e l d (72,729,434 b b l s o i l , 1,892,616 MCF g a s ; 1917-79) S. A. T r i b a l "A" Unit

Winkleman Dome F i e l d i s l o c a t e d i n Township 2 North, Ranges 1 and

2 West, Fremont County, and covers 2,269 a c r e s of t h e Wind River I n d i a n Reservation.

The f i e l d was discovered i n February, 1944, when

a p r o d u c t i v e w e l l was completed i n t h e Tensleep Sandstone between 2,915 and 3,205 f e e t .

The f i r s t w e l l was d r i l l e d i n 1917; however,

only shows of gas i n t h e Lakota Sandstone and g a s and o i l i n t h e Sundance Formation were encountered. Water i n j e c t i o n t o t h e Tensleep r e s e r v o i r a t t h e S. A . T r i b a l 11

A1 1 Unit s t a r t e d i n January, 1967, w i t h t h e purpose of a c c e l e r a t i n g

o i l production by supplementing t h e a c t i v e water d r i v e of t h e r e s e r v o i r . The Tensleep r e s e r v o i r covers about 1,000 a c r e s w i t h an average pay zone t h i c k n e s s of 160 f e e t . A s of December, 1979, t h e r e were 22 i n j e c t i o n w e l l s , 14 of which

a r e d u a l l y completed i n t h e Tensleep and Phosphoria (Embar) r e s e r v o i r s . Twelve of t h e w e l l s have a l s o i n j e c t e d n a t u r a l gas i n t o t h e Tensleep. Cumulative water i n j e c t i o n , through t h e above d a t e , was 84,733,526 9 b a r r e l s (3.5588 x 10 g a l l o n s ) of produced Tensleep water. volume of gas i n j e c t e d t o t h e Tensleep was n o t r e p o r t e d . i n j e c t i o n p r e s s u r e s have ranged from 25 t o 1,300 p s i .

The Average

A 16 w e l l steam i n j e c t i o n p r o j e c t , operated by Amoco Production Company, was s t a r t e d i n 1965. t h e Nugget Sandstone.

The i n j e c t i o n w e l l s a r e completed i n

According t o t h e O i l and Gas Commission's

1979 S t a t i s t i c s Book, a l l 1 6 of t h e w e l l s were a c t i v e d u r i n g 1979. F u r t h e r d e t a i l s on t h e p r o j e c t a r e a v a i l a b l e i n SPE paper 2131, p r e s e n t e d a t t h e Rocky Mountain Regional Meeting of t h e S o c i e t y of Petroleum Engineers of AIME, B i l l i n g s , Montana, June 5-7,

1968.

Phosphoria Unit The Phosphoria r e s e r v o i r of Winkleman Dome covers an a r e a of about 1,414 a c r e s w i t h a n average pay zone t h i c k n e s s of 54 f e e t .

Pressure

d a t a , from producing w e l l s completed i n t h e Phosphoria, i n d i c a t e t h a t t h e primary producing mechanism of t h e r e s e r v o i r was f l u i d expansion w i t h a l i m i t e d water d r i v e .

It was e s t i m a t e d t h a t primary

recovery would b e 17 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e and t h a t secondary recovery would b e 7.5 p e r c e n t of t h e o r i g i n a l o i l i n p l a c e . Water i n j e c t i o n t o t h e Phosphoria s t a r t e d i n August, 1962.

A s of

December, 1979, t h e r e were 38 i n j e c t i o n w e l l s completed i n t h e Phosphoria reservoir.

F i f t e e n of t h e w e l l s a r e d u a l i n j e c t o r s t o t h e Phosphoria

and Tensleep r e s e r v o i r s o r t o two s e p a r a t e i n t e r v a l s w i t h i n t h e Phosphoria. water.

S e v e r a l of t h e w e l l s a l s o i n j e c t n a t u r a l g a s w i t h t h e

T h i r t y - s i x of t h e w e l l s were a c t i v e l y i n j e c t i n g d u r i n g t h e

second h a l f of 1979.

Cumulative water i n j e c t i o n between August,

9 1962, and December, 1979, was 47,401,136 b a r r e l s (1.9908 x 10 g a l l o n s ) of produced Phosphoria Formation w a t e r .

Average i n j e c t i o n

p r e s s u r e s d u r i n g t h a t p e r i o d ranged from 100 t o 1,750 p s i .

Casing Record:

I n j e c t i o n W e l l #3LO, T2N-R1W-29 bad, Winkleman Dome F i e l d , Phosphoria Unit, T o t a l Depth = 3560 f e e t .

Casing S i z e

Wt.

(#/ft)

Cement

Hole S i z e

Depth S e t

36

12-1/4"

169'

250 s a c k s

14

8-3 /4"

3558'

315 s a c k s

Worland F i e l d (17,671,353 b b l s o i l , 361,691,699 MCF gas Worland Unit A s i n g l e w e l l s a l t water d i s p o s a l system, operated by Union O i l

Company of C a l i f o r n i a , began i n j e c t i o n t o t h e Phosphoria Formation i n 1977.

The w e l l i s l o c a t e d i n S e c t i o n 20, Township 48 North, Range

92 West, Washakie County, and i s completed a t a d e p t h of 10,078 f e e t . F u r t h e r d e t a i l s on t h e system were n o t a v a i l a b l e from t h e f i l e s of t h e O i l and Gas Commission.

111.

I N

S I T U

I N J E C T I O N

U R A N I U M

P R O J E C T S

A s of l a t e 1980, p e r m i t t e d i n s i t u uranium o p e r a t i o n s i n Wyoming i n c l u d e t h r e e commercial s c a l e mines, and an a d d i t i o n a l 1 7 r e s e a r c h and development sites.

The r e l a t i v e l y l a r g e number of r e c e n t l y i s s u e d

r e s e a r c h and development p e r m i t s i n d i c a t e s i n d u s t r y ' s i n c r e a s e d i n t e r e s t i n i n s i t u uranium development.

Current i n s i t u mining t e c h n i q u e s ,

however, can produce d e g r a d a t i o n of ground w a t e r through m o b i l i z a t i o n of t o x i c elements and i n c r e a s e d d i s s o l v e d s o l i d s , though a v a i l a b l e i n f o r m a t i o n s u g g e s t s t h a t t h e e x t e n t of ground-water contamination i s s i t e s p e c i f i c and dependent on l o c a l y geology, hydrology, and e l e c t r o chemical c o n d i t i o n s (Galloway and o t h e r s , 1980; Walsh and o t h e r s , 1979). The f o l l o w i n g s e c t i o n s review t h e geology of sedimentary uranium d e p o s i t s , i n s i t u mining and r e s t o r a t i o n t e c h n i q u e s , p o t e n t i a l environmental impacts a s s o c i a t e d w i t h a c t i v e s o l u t i o n mining, r e s t o r a t i o n , and p o s t - r e s t o r a t i o n p e r i o d s , a s w e l l a s t h e c u r r e n t s t a t u s of Wyoming i n s i t u uranium o p e r a t i o n s .

OCCURRENCE AND CHARACTERISTICS OF URANIUM DEPOSITS I n s i t u uranium e x t r a c t i o n t e c h n i q u e s a r e g e n e r a l l y a p p l i e d sedimentary uranium d e p o s i t s .

These d e p o s i t s , o f t e n termed r o l l

f r o n t s , appear a s e l o n g a t e d t u b u l a r masses i n sandstone o r conglomerate l e n s e s interbedded i n s h a l e s (McKelvey and o t h e r s , 1955).

Roll front

d e p o s i t s a r e b e l i e v e d t o form where shallow uranium-bearing ground

w a t e r s encounter reducing c o n d i t i o n s .

Uranium i s g e n e r a l l y i n s o l u b l e

under reducing c o n d i t i o n s and p r e c i p i t a t e s p r i n c i p a l l y a s u r a n a n i t e (U02), c o f f i n i t e [(USiOq)l-x(OH4x)],

or uraniferrous asphaltite Often a s s o c i a t e d w i t h

( a s p h a l t i c o r g a n i c matter c o n t a i n i n g uranium).

uranium d e p o s i t i o n a r e p y r i t e and/or m a r c a s i t e (FeS ) , along w i t h l e s s e r 2 amounts of vanadium, selenium, a r s e n i c , and molybdenum m i n e r a l s (Stanton, 1972).

Non-metallic m i n e r a l s commonly found w i t h i n s e d i -

mentary uranium d e p o s i t s i n c l u d e gypsum, c a l c i t e , dolomite, f l u o r i t e , b a r i t e , and k a o l i n i t e . The c o n c e n t r a t i o n of uranium a s U 0 found i n uranium r o l l f r o n t 3 8' d e p o s i t s i n t h e Colorado p l a t e a u , commonly v a r i e s from 0 . 1 t o 1.0 p e r c e n t , though may be a s h i g h a s 20 p e r c e n t ( S t a n t o n , 1972).

Concen-

t r a t i o n s of vanadium, selenium, a r s e n i c , and molybdenum a r e h i g h l y v a r i a b l e , and a 1 1 may n o t b e found w i t h i n one d e p o s i t .

Core samples

i n s o u t h Texas contained el-1,638 micrograms p e r l i t e r ( p g / l ) Se, 1-1,370 p g / l Mo, and 1-129 p g / l A s (Galloway and o t h e r s , 1980). Vanadium c o n c e n t r a t i o n s i n Utah r e p o r t e d by S t a n t o n (1972) v a r i e d from 0.2 t o 1.0 p e r c e n t . REVIEW OF CURRENT TECHNOLOGIES I n S i t u Mining Techniques S o l u t i o n mining of sedimentary uranium o r e e s s e n t i a l l y r e v e r s e s t h e hydrochemical p r o c e s s e s which i n i t i a l l y formed t h e d e p o s i t s .

A

s o l u t i o n impregnated w i t h 300-1,500 m i l l i g r a m s p e r l i t e r (mg/l) of a n o x i d a n t (0

2'

H202, NaC103) and 1,000-10,000 mg/l of an a l k a l i n e

( 3 H 9) uranium complexing agent (Na-CO

deposit.

3'

NH

4-

CO ) i s i n j e c t e d i n t o t h e 3

The o x i d i z i n g agent r e n d e r s reduced uranium m i n e r a l s u n s t a b l e ,

l i b e r a t i n g uranium i n t o s o l u t i o n a s UO

+, w h i l e

2

t h e c a r b o n a t e complexing

agent enhances uranium s o l u b i l i t y through t h e formation of ( ~ 0 (CO ~ ' -) ~ ) 3 2

0

(Langmuir , 1978)

.

An a r r a y of production w e l l s i s

used t o withdraw t h e uranium-bearing

fluid.

The s i z e and shape of t h e

i n j e c t i o n / p r o d u c t i o n w e l l a r r a y i s dependent upon t h e s i z e and permea b i l i t y of t h e uranium o r e zone b e i n g solution-mined.

R e s t o r a t i o n Techniques When t h e uranium c o n c e n t r a t i o n of t h e e x t r a c t drops below l e v e l s considered economic, i n j e c t i o n of mining f l u i d s t o p s and s i t e r e s t o r a t i o n begins.

R e s t o r a t i o n g e n e r a l l y i n v o l v e s pumping t h e mine u n i t

a f t e r i n j e c t i o n h a s stopped, i n o r d e r t o withdraw any l i x i v i a n t remaining w i t h i n t h e d e p o s i t and t o draw u n a f f e c t e d formation water through t h e mine zone. sweep.

T h i s p r o c e s s i s r e f e r r e d t o a s a ground-water

When a s o l u t i o n mine s i t e f a i l s t o respond t o a ground-water

sweep, chemical c l e a n s i n g and r e i n j e c t i o n of produced f l u i d s may b e employed t o reduce drawdowns.

A 10-15 p e r c e n t l o s s of f l u i d i s

g e n e r a l l y a s s o c i a t e d w i t h chemical c l e a n s i n g and r e i n j e c t i o n r e s t o r a t i o n practices.

S i t e r e s t o r a t i o n i s achieved when predevelopment hydro-

chemical c o n d i t i o n s e x i s t w i t h i n t h e mined d e p o s i t .

POTENTIAL ENVIRONMENTAL IMPACTS Impacts of A c t i v e S o l u t i o n Mining During t h e c o u r s e of a c t i v e s o l u t i o n mining, h y d r o l o g i c e f f e c t s a r e minimal; t h e i n j e c t e d s o l u t i o n i s r e c y c l e d , thereby dampening any e f f e c t s of a r t i f i c i a l r e c h a r g e and d i s c h a r g e on t h e ore-bearing a q u i f e r . G e n e r a l l y , some drawdown i s allowed t o occur i n t h e v i c i n i t y of

producing w e l l s , enhancing recovery and l i m i t i n g t h e spread of mining fh i d . S i g n i f i c a n t changes occur i n t h e hydrochemistry of t h e ore-bearing aquifer.

The i n j e c t e d s o l u t i o n d i s p l a c e s o r e formation w a t e r s , pro-

ducing an aqueous environment r e l a t i v e l y h i g h e r i n TDS (2,000-12,000 m g / l ) , m e t a l complexing i o n s , pH and Eh, depending upon t h e type and s t r e n g t h of l i x i v i a n t employed.

Reduced m i n e r a l o g i e s become u n s t a b l e ,

and t h e i n j e c t e d s o l u t i o n t h e r e f o r e mobilizes uranium and geochemically s i m i l a r elements, n o t a b l y vanadium, selenium, a r s e n i c , and molybdenum. I r o n s u l f i d e s , o f t e n abundant i n sedimentary uranium d e p o s i t s , a r e a l s o o x i d i z e d , r e l e a s i n g hydrogen and s u l f a t e i o n s i n t o s o l u t i o n and forming i n s o l u b l e f e r r i c oxides o r hydroxides.

A c i d i t y generated

by s u l f i d e o x i d a t i o n may b e consumed through carbonate b u f f e r i n g o r s i l i c a t e hydrolysis releasing

tau,

M~*,

~a',

K,'

HC03

-

,

and Si02

into solution. Chemical a l t e r a t i o n of major c a t i o n c o n c e n t r a t i o n s i n o r e zone w a t e r s a l s o t a k e s p l a c e through exchange r e a c t i o n s involving c l a y s , z e o l i t e s , and o r g a n i c m a t e r i a l .

+ or

The i n j e c t e d c a t i o n s p e c i e (Na

+

NH4 ) i s g e n e r a l l y t h e dominant p o s i t i v e i o n i n s o l u t i o n .

Assuming a

sodium l i x i v i a n t , t h e r e p r e s e n t a t i v e exchange r e a c t i o n

+ ZNa aqueous

+BIZ+

clay

:zN~+

clay

+M'+

aqueous

(where M r e p r e s e n t s an exchangeable c a t i o n w i t h charge Z ) i s d r i v e n strongly t o the r i g h t .

I f a concentrated i n j e c t i o n f l u i d i s used,

sodium may s a t u r a t e exchange s i t e s , r e l e a s i n g v i r t u a l l y a l l exchangeable cations i n t o solution.

Ion exchange, along w i t h s o l u t i o n and

o x i d a t i o n r e a c t i o n s , may a l t e r t h e major i o n chemistry of t h e i n j e c t e d

f l u i d s u f f i c i e n t l y t o cause s o l u t i o n o r p r e c i p i t a t i o n of non-metallic phases such a s c a l c i t e o r gypsum. The e f f e c t s of i n j e c t i o n and mining s o l u t i o n - a q u i f e r i n t e r a c t i o n a r e g e n e r a l l y l i m i t e d t o t h e o r e zone i t s e l f , through balanced r a t e s of i n j e c t i o n and p r o d u c t i o n and w e l l f i e l d design.

E f f e c t s of mine

f l u i d m i g r a t i o n o u t of mined zones a r e dependent upon many h y d r o l o g i c f a c t o r s , b u t t h e m o b i l i t y of uranium and o t h e r t r a c e elements i s l a r g e l y c o n t r o l l e d by t h e Eh c o n d i t i o n s of t h e e x c u r s i o n a r e a .

Movement i n t o

a reducing environment would r e s u l t i n p r e c i p i t a t i o n of t r a c e elements i n a manner analogous t o t h e n a t u r a l d e p o s i t i o n a l p r o c e s s .

Galloway

and o t h e r s (1980) c a l c u l a t e d t h e e x t e n t of t r a c e element movement i n t o r e d u c i n g c o n d i t i o n s , assuming an e x c u r s i o n w a t e r volume of

lo6

liters

and a p y r i t e c o n c e n t r a t i o n of 1 p e r c e n t i n c o n t a i n i n g 1,000 mg/l 0 2' t h e zone a f f e c t e d . 50 m

3

Under t h e s e c o n d i t i o n s , t h e p y r i t e contained i n

of sediment would b e s u f f i c i e n t t o consume a l l d i s s o l v e d oxygen.

I f t h e e x c u r s i o n moved through a 100 m

2

c r o s s - s e c t i o n a l a r e a , only a

0.5 meter t h i c k n e s s of sediment would b e r e q u i r e d t o reduce t h e f l u i d and r e n d e r uranium and geochemically s i m i l a r elements i n s o l u b l e . Excursions i n t o o x i d i z i n g environments would reduce s o l u b i l i t y c o n t r o l s on t h e s e t r a c e elements, though a d s o r p t i o n onto i r o n o x i d e s / hydroxides and c l a y s would l i k e l y reduce t r a c e element l e v e l s (Howard, 1972; Kaback, 1977; Langmuir, 1978; Gulens and o t h e r s , 1979).

The

e f f i c i e n c y of t r a c e element removal by a d s o r p t i o n h a s n o t been q u a n t i f i e d , however. Concentrations of major i o n s and t o t a l d i s s o l v e d s o l i d s i n an e x c u r s i o n zone would l i k e l y remain h i g h u n t i l a f f e c t e d by a mechanical p r o c e s s such a s d i l u t i o n o r d i s p e r s i o n .

Excursions a r e g e n e r a l l y

c h a r a c t e r i z e d by i n c r e a s e s i n t h e c o n c e n t r a t i o n s of d i s s o l v e d s o l i d s ( o r c o n d u c t i v i t y ) , s u l f a t e , c a r b o n a t e s p e c i e s , o r o t h e r major i o n s , r a t h e r than uranium o r o t h e r t r a c e elements (Wyoming Department of Environmental Q u a l i t y

-

Land Q u a l i t y D i v i s i o n , Information F i l e s ) . Impacts of R e s t o r a t i o n

Impacts a s s o c i a t e d w i t h r e s t o r a t i o n a r e n o t w e l l known a s few commercial-scale i n s i t u uranium developments have completed r e s t o r a tion efforts.

R e s t o r a t i o n of test sites h a s n o t always been s u c c e s s f u l .

A t t h e Highland t e s t s i t e i n Campbell County, Wyoming, ground-water sweep r e s t o r a t i o n h a s been attempted c o n t i n u o u s l y s i n c e 1974, w i t h o u t r e t u r n i n g o r e zone w a t e r s t o b a s e l i n e c o n d i t i o n s .

Galloway and o t h e r s

(1980) noted a s i m i l a r slow chemical response t o r e s t o r a t i o n pumpage a t i n s i t u s i t e s i n Texas.

Where r e s t o r a t i o n e f f o r t s r e q u i r e long-

term pumpage, s i g n i f i c a n t drawdowns may occur w i t h i n t h e o r e a q u i f e r . Chemical c l e a n s i n g and r e - i n j e c t i o n of t h e water produced d u r i n g r e s t o r a t i o n may be employed i n such c a s e s , reducing t o t a l r e s t o r a t i o n r e l a t e d water withdrawals by 85 t o 90 p e r c e n t .

A t t e s t s i t e s where

chemical c l e a n s i n g and r e - i n j e c t i o n have been u t i l i z e d (Lrigaray i n s i t u s i t e , Johnson County, Wyoming; Bison Basin i n s i t u s i t e , Fremont County, Wyoming), f i v e t o e i g h t mine a r e a p o r e volumes of f l u i d have been r e c y c l e d through t h e d e p o s i t b e f o r e r e s t o r a t i o n was achieved. The slow r e t u r n of mine zone w a t e r s t o b a s e l i n e c o n d i t i o n s , d e s p i t e r e p e a t e d f l u s h i n g s , i s poorly understood.

I n t h e Texas

uranium d i s t r i c t , Galloway and o t h e r s (1980) noted p e r s i s t e n t l y h i g h c o n c e n t r a t i o n s of d i s s o l v e d s o l i d s , t h e i n j e c t e d c a t i o n s p e c i e , and uranium and geochemically s i m i l a r elements i n produced r e s t o r a t i o n

waters.

High d i s s o l v e d s o l i d s c o n c e n t r a t i o n s may r e s u l t from s o l u t i o n

of m i n e r a l s formed d u r i n g a c t i v e mining.

Slow r e l e a s e of t h e i n j e c t e d

c a t i o n from exchange s i t e s l i k e l y causes t h e observed h i g h l e v e l s of t h i s i o n , i n s p i t e of continued f l u s h i n g , e s p e c i a l l y i f an ammoniumbased l i x i v i a n t was used f o r mining (Walsh and o t h e r s , 1979). The r e s p o n s e of uranium and geochemically s i m i l a r t r a c e elements d u r i n g r e s t o r a t i o n i s l a r g e l y c o n t r o l l e d by t h e Eh-pH of t h e inflowing waters.

An i n f l u x of reducing w a t e r , more l i k e l y t o occur d u r i n g a

ground-water

sweep than d u r i n g a c l e a n s i n g i r e - i n j e c t i o n r e s t o r a t i o n ,

would r e - e s t a b l i s h premining Eh c o n d i t i o n s w i t h i n t h e d e p o s i t , r e s u l t i n g i n p r e c i p i t a t i o n of reduced m i n e r a l s .

The s u l f i d e c o n t e n t of a reducing

i n f l o w would b e important f o r formation of i n s o l u b l e m e t a l - s u l f i d e phases. An o x i d i z i n g i n f l o w would r e s u l t i n o x i d a t i o n of p o r t i o n s of t h e d e p o s i t t h a t s u r v i v e d mining, o r o x i d a t i o n of subeconomic o r e s a d j a c e n t t o t h e mined zone.

Both t h e s e e f f e c t s would prolong h i g h t r a c e element

l e v e l s i n mine zone w a t e r s d u r i n g r e s t o r a t i o n . Release of t r a c e m e t a l s absorbed on c l a y s and oxide/hydroxide phases ( e s p e c i a l l y i r o n hydroxides formed through p y r i t e o x i d a t i o n ) may a l s o h i n d e r r e s t o r a t i o n e f f o r t s .

Adsorption/desorption p r o c e s s e s ,

though n o t t o t a l l y understood, a r e a p p a r e n t l y c o n t r o l l e d by pH and complexing i o n (CO

3

-

, SO4 -)

concentrations.

Within t h e pH range of

most ground w a t e r s , oxide/hydroxide phases s t r o n g l y adsorb uranium, selenium, and molybdenum, w i t h t h e degree of a d s o r p t i o n modified by t h e presence of complexing i o n s (Langmuir, 1978; Kaback, 1977; Howard, 1977).

Post-Restoration

Impacts

L i t t l e i s known concerning long-term impacts a t a r e s t o r e d i n s i t u uranium mine.

During t h e s o l u t i o n mining p r o c e s s , however, t h e t y p e ,

amount, and p a r t i t i o n i n g of elements w i t h i n t h e a q u i f e r m a t r i x i s a l t e r e d , through s o l u t i o n and/or formation of d i f f e r e n t m i n e r a l s and oxide/hydroxide phases, and through exchange and a d s o r p t i o n / d e s o r p t i o n reactions.

While r e s t o r a t i o n r e t u r n s mine zone w a t e r s t o premining

c o n d i t i o n s , t h e d e g r e e t o which t h e a q u i f e r m a t r i x i s r e s t o r e d i s u n c e r t a i n and l i k e l y s m a l l .

Water-rock i n t e r a c t i o n s w i t h i n t h e r e s t o r e d

d e p o s i t may d i f f e r a p p r e c i a b l y from t h o s e t h a t occurred p r e v i o u s t o mining, r e s u l t i n g i n a l t e r e d downgradient hydrochemistry. The t y p e and amount of chemical s p e c i e s mobilized w i t h i n t h e postmining a q u i f e r depend

upon t h e type, amount, and p a r t i t i o n i n g of

elements w i t h i n t h e a q u i f e r m a t r i x and t h e hydrochemistry of i n f l o w i n g ground w a t e r s .

Migration of t h e mobilized s p e c i e s would depend l a r g e l y

upon t h e hydrochemical c o n d i t i o n s e x i s t i n g downgradient from t h e restored site. PHYSICAL DESCRIPTIONS OF I N SITU URANIUM SITES The f o l l o w i n g s e c t i o n d e s c r i b e s t h e geology, hydrology, and developmental h i s t o r y of n i n e i n s i t u uranium s i t e s w i t h i n Wyoming. Information f o r t h e s e d e s c r i p t i o n s was gathered from t h e f i l e s of t h e Wyoming Department of Environmental Q u a l i t y , Land Q u a l i t y D i v i s i o n (DEQ-LQD).

P e r m i t t e d s i t e s which a r e n o t d i s c u s s e d h e r e a r e c u r r e n t l y

c l a s s e d a s c o n f i d e n t i a l by t h e Wyoming DEQ-LQD, mine o p e r a t o r .

a t t h e r e q u e s t of t h e

R e s t o r a t i o n c r i t e r i a f o r Wyoming i n s i t u uranium developments a r e s e t by t h e Wyoming DEQ-LQD and r e q u i r e t h a t a l l chemical parameters a f f e c t i n g f u t u r e water u s e b e r e t u r n e d t o pre-mining c o n c e n t r a t i o n s , S p e c i f i c a l l y , f o r any given chemical parameter of concern a b a s e l i n e c o n c e n t r a t i o n range and average i s e s t a b l i s h e d f o r t h e mine u n i t . Following r e s t o r a t i o n , a l l sampling p o i n t s used t o e s t a b l i s h b a s e l i n e c o n d i t i o n s must y i e l d parameter c o n c e n t r a t i o n s w i t h i n t h e b a s e l i n e c o n c e n t r a t i o n r a n g e , and t h e average of a11 parameter c o n c e n t r a t i o n s must b e e q u a l t o o r less than t h e b a s e l i n e average.

Where t h i s degree

of r e s t o r a t i o n cannot b e o b t a i n e d , l e s s e r s t a n d a r d s may b e a p p l i e d i f t h e Wyoming DEQ-LQD determines t h a t t h e b e s t management p r a c t i c e h a s been a p p l i e d d u r i n g t h e r e s t o r a t i o n e f f o r t ( ~ y o m i n gDEQ-LQD,

1980).

The Wyoming DEQ-LQD r e q u i r e s t h a t d i s t i n c t i v e components of t h e mining f l u i d b e monitored o u t s i d e t h e mine zone.

Where t h e concen-

t r a t i o n s of two such components exceed upper c o n t r o l l i m i t s ( h i g h e s t expected c o n c e n t r a t i o n s under n a t u r a l c o n d i t i o n s ) , t h e monitor w e l l y i e l d i n g t h e e x c e s s e s i s placed on e x c u r s i o n s t a t u s .

The cause of t h e

e x c u r s i o n must t h e n b e determined, and t h e a f f e c t e d zone r e t u r n e d t o A s of l a t e 1980, however, no

pre-excursion chemical c o n d i t i o n s .

c r i t e r i a f o r d e f i n i n g upper c o n t r o l l i m i t s had been e s t a b l i s h e d .

Such

d e f i n i t i o n s a r e c u r r e n t l y made by t h e mine o p e r a t o r and a r e s u b j e c t t o a p p r o v a l by t h e Wyoming DEQ-LQD.

Generally, t h e upper c o n t r o l l i m i t

f o r a given parameter i s d e f i n e d a s :

(1) t h e e s t a b l i s h e d b a s e l i n e v a l u e

p l u s a p e r c e n t a g e of t h e b a s e l i n e v a l u e ; o r (2) t h e e s t a b l i s h e d basel i n e v a l u e p l u s some s e t v a l u e .

Bison Basin S i t e (Commercial-Scale) The Bison Basin i n s i t u uranium s i t e i s l o c a t e d i n S e c t i o n 25, Township 27 North, Range 97 West, and S e c t i o n 30, Township 27 North, Range 96 West, Fremont County, Wyoming. a r e a covers 751 a c r e s .

The p e r m i t t e d mine

The uranium o r e body a t Bison Basin l i e s w i t h i n

t h e Laney Member of t h e Green River Formation, roughly 350 f e e t t o 400 f e e t below t h e s u r f a c e .

The ore-bearing sandstone averages 15

f e e t i n t h i c k n e s s , c o n t a i n s a s i x - f o o t t h i c k m i n e r a l i z e d zone, and i s o v e r l a i n and' u n d e r l a i n by s h a l e s . e a s t a t about 2 d e g r e e s . t h e o r e body.

S t r a t a a t t h e s i t e d i p t o t h e south-

L o c a l l y minor f a u l t s c u t t h e a r e a , i n c l u d i n g

O r e s a n d s t o n e p e r m e a b i l i t i e s v a r y from 2.8 t o 17 g p d / f t

w i t h t r a n s m i s s i v i t i e s of 42 t o 300 g p d / f t .

2

While no p e r m e a b i l i t y

e s t i m a t e s f o r t h e c o n f i n i n g s h a l e s a r e a v a i l a b l e , a q u i f e r tests on t h e o r e s a n d s t o n e showed no evidence f o r s i g n i f i c a n t leakage. A p i l o t i n s i t u t e s t was conducted a t Bison Basin from A p r i l 1

through August 1, 1979.

Four w e l l s were used t o i n j e c t a sodium

c a r b o n a t e l b i c a r b o n a t e and oxygen e n r i c h e d s o l u t i o n a t a c o n s t a n t r a t e of 25 gpm.

Three p r o d u c t i o n w e l l s were employed t o withdraw t h e

uranium-bearing f l u i d , and f i v e w e l l s surrounding t h e s i t e were used t o monitor water q u a l i t y i n a d j a c e n t zones.

Approximately 0.93 a c r e s

were mined d u r i n g t h e t e s t . T e s t s i t e r e s t o r a t i o n began on August 1 and was completed on August 1 4 , 1979.

R e s t o r a t i o n was accomplished through r e - i n j e c t i o n of

produced w a t e r s f o l l o w i n g r e v e r s e osmosis c l e a n s i n g .

Roughly e i g h t

p o r e volumes of f l u i d were r e c y c l e d through t h e system. Commercial-scale development of t h e Bison Basin s i t e h a s been approved by t h e Wyoming DEQ-LQD.

The planned f a c i l i t y w i l l have a

,

p l a n t c a p a c i t y of 1,200 gpm and i s expected t o produce about 200 t o n s of uranium ( a s U 0 ) annually. 3 8

The s i t e w i l l be d i v i d e d i n t o f o u r

mining u n i t s , and w i l l c o n t a i n a t o t a l of 620 i n j e c t i o n w e l l s , 320 p r o d u c t i o n w e l l s , and 58 monitor w e l l s .

A t o t a l of 56.1 a c r e s of

uranium w i l l b e mined.

I n j e c t i o n w e l l p r e s s u r e s a r e expected t o be

between 60 and 100 p s i .

R e s t o r a t i o n a c t i v i t i e s a t t h e commercial

development w i l l b e s i m i l a r t o t h o s e employed a t t h e t e s t s i t e . C o l l i n s Draw S i t e (Research and Development) The C o l l i n s Draw i n s i t u uranium s i t e is l o c a t e d i n t h e S E ~ N , E~, N E ~ ,S e c t i o n 35 and t h e S&,

NWk,

SW~S , e c t i o n 36, Township 43 North,

Range 76 West, Campbell County, Wyoming. 42.4 a c r e s .

The p e r m i t t e d a r e a covers

The o r e body a t C o l l i n s Draw i s 50 t o 55 f e e t t h i c k , l i e s

450 t o 500 f e e t below t h e s u r f a c e , and is o v e r l a i n and u n d e r l a i n by claystones.

Ore zone p e r m e a b i l i t i e s range from 3 t o 5 g p d / f t

and t r a n s m i s s i v i t i e s a r e between 146 and 270 g p d / f t .

2

,

No continuous

s a n d s t o n e b o d i e s l i e above o r below t h e o r e body. The C o l l i n s Draw s i t e i s p e r m i t t e d f o r r e s e a r c h and development testing.

T e s t i n g w a s scheduled t o b e g i n i n May, 1979, and c o n t i n u e f o r

30 months, though t h e c u r r e n t f i e l d s t a t u s i s n o t a v a i l a b l e . 100-foot by 100-foot w e l l p a t t e r n s a r e planned.

Several

The i n j e c t e d s o l u t i o n

w i l l c o n t a i n 5,000 t o 15,000 mg/l N H ~ - C O ~ / H C O and ~ 1,000 t o 2,000 mg/l *2O2*

I n j e c t i o n p r e s s u r e s a r e expected t o be l e s s t h a n 100 p s i .

R e s t o r a t i o n w i l l b e attempted through c l e a n s i n g and r e - i n j e c t i o n of produced f l u i d s .

Highland Mine P i l o t 1 & 2 (Research and Development) The Highland mine s i t e , o r i g i n a l l y p e r m i t t e d f o r open p i t and underground uranium mining, was a d d i t i o n a l l y p e r m i t t e d f o r i n s i t u uranium mining r e s e a r c h and development o p e r a t i o n s beginning i n 1972. The mine s i t e i s l o c a t e d i n S e c t i o n s 1 7 , 20-22,

27-29,

33, and 34,

Township 36 North, Range 72 West, and S e c t i o n s 23 and 24, Township 36 North, Range 73 West, Converse County, Wyoming.

Exxon h a s requested

a p e r m i t t e d a r e a f o r i n s i t u mining of 1,240 a c r e s . The m i n e r a l i z e d zone i s l o c a t e d i n t h e Highland Sand Group of t h e F o r t Union Formation, roughly 360 t o 430 f e e t below t h e s u r f a c e .

The

Highland Sand Group i s composed of t h r e e d i s t i n c t sands s e p a r a t e d and confined by s i l t s t o n e s and s h a l e s ,

The p e r m e a b i l i t y of t h e ore-bearing

sand i s 19 g p d / f t and p o r o s i t y i s 29 p e r c e n t . s h a l e is less t h a n 2 x

gpd/ft

2

P e r m e a b i l i t y of t h e

.

An i n i t i a l p i l o t t e s t was conducted from March, 1972, t o November, 1974, u t i l i z i n g one i n j e c t i o n w e l l , s i x producing w e l l s , and s i x observation wells.

A sodium carbonate-bicarbonate l i x i v i a n t was

i n j e c t e d a t a s u r f a c e p r e s s u r e of 50 p s i .

Produced f l u i d s had an

average g r a d e of 25 mg/l U 0 3 8' R e s t o r a t i o n of t h e i n i t i a l t e s t s i t e began i n 1974, and i s c u r r e n t l y ongoing.

A ground-water sweep i s being employed w i t h pumped

water going t o s o l a r e v a p o r a t i o n ponds. I n 1978, a second p i l o t a r e a was developed w i t h 25 i n j e c t i o n , p r o d u c t i o n , and monitor w e l l s .

This a r e a was placed i n o p e r a t i o n d u r i n g

6 1979, and had produced 39.78 x 10 g a l l o n s of l e a c h s o l u t i o n a s of J u l y , 1980.

Long-range development p l a n s f o r commercial s c a l e i n s i t u uranium mining of t h e Highland s i t e i n c l u d e t h e d r i l l i n g of roughly 74 i n j e c t i o n and 446 p r o d u c t i o n w e l l s , covering 70 a c r e s .

I n j e c t i o n w e l l s w i l l be

o f f s e t by f o u r p r o d u c t i o n w e l l s w i t h o b s e r v a t i o n w e l l s e n c i r c l i n g t h e operating area.

Monitor w e l l s w i l l be completed i n t o t h e a q u i f e r above

and below t h e o r e zone.

Observation w e l l s w i l l be 250-350 f e e t a p a r t

and approximately 200 f e e t from t h e production p e r i m e t e r .

The d i s t a n c e

between p r o d u c t i o n and i n j e c t i o n w e l l s w i l l be about 70 f e e t .

The

proposed p l a n t i s designed t o p r o c e s s 1,200 gal/min. Excursion H i s t o r y During t h e i n i t i a l t e s t i n g two e x c u r s i o n s i n v o l v i n g e l e v a t e d l e v e l s of uranium occurred w i t h i n t h e ore-sandstone body.

They were c o n t r o l l e d

by i n c r e a s i n g t h e p r o d u c t i o n and/or d e c r e a s i n g t h e i n j e c t i o n r a t e , which s u g g e s t s t h a t t h e i n i t i a l i n j e c t i o n - p r o d u c t i o n r a t e s were t h e c a u s e of mine f l u i d m i g r a t i o n . An e x c u r s i o n a s s o c i a t e d w i t h t h e second p i l o t s i t e was l i n k e d t o a f a u l t y i n j e c t i o n w e l l casing.

Leaching f l u i d was d e t e c t e d i n an

o v e r l y i n g a q u i f e r when s p e c i a l o b s e r v a t i o n w e l l s were d r i l l e d .

Aquifer

clean-up was accomplished through production of t h e s e o b s e r v a t i o n w e l l s . I r i g a r a y Ranch (Commercial S c a l e ) The I r i g a r a y mine s i t e i s l o c a t e d i n S e c t i o n s 5, 8 , 9, and 1 6 , Township 45 North, Range 77 West, Johnson County, Wyoming.

The t o t a l

p e r m i t t e d mine a r e a covers 600.25 a c r e s w i t h a n e s t i m a t e d 1 9 1 a c r e s t o be d i s t u r b e d by a l l mining r e l a t e d a c t i v i t i e s .

A s of August, 1980,

126.24 a c r e s have been developed, i n c l u d i n g 12 a c r e s of t h e w e l l f i e l d . This s i t e was t h e f i r s t commercial-scale o p e r a t i o n p e r m i t t e d i n Wyoming, and became o p e r a t i o n a l i n August, 1978.

The r o l l - t y p e uranium m i n e r a l i z a t i o n is l o c a t e d i n t h e 100-foot t h i c k a r k o s i c Upper I r i g a r a y Sandstone of t h e Wasatch Formation. d i r e c t i o n of b o t h r e g i o n a l d i p and h y d r a u l i c g r a d i e n t i s n o r t h .

The The

m i n e r a l i z e d zone l i e s an average of 200 f e e t below t h e s u r f a c e , w i t h c l a y s t o n e s a t t h e s i t e immediately above and below t h e ore-bearing sandstone.

P e r m e a b i l i t y of t h e o r e sandstone i s 3.5 gpd/f t 2 and

p o r o s i t y i s 23 p e r c e n t .

Ore zone t r a n s m i s s i v i t y i s 1,000 g p d / f t .

-4 2 P e r m e a b i l i t y of t h e c o n f i n i n g c l a y s t o n e s i s below 9 x 10 gpd/ft An i n s i t u p i l o t t e s t was conducted i n 1976.

.

Three f i v e - s p o t

test p a t t e r n s were used t o i n j e c t a n ammonium bicarbonate-carbonate

solution.

Monitor w e l l s were placed 200 f e e t a p a r t , and 400 f e e t from

the operating w e l l f i e l d . T e s t s i t e r e s t o r a t i o n began i n May, 1977.

R e s t o r a t i o n was

accomplished by r e - i n j e c t i n g recovered water a f t e r contaminant removal by means of e i t h e r i o n exchange o r a combination of chemical p r e c i p i t a t i o n and r e v e r s e osmosis t r e a t m e n t .

Using t h e r e v e r s e osmosis p r o c e s s

approximately f i v e p o r e volumes were r e c y c l e d . Commercial-scale o p e r a t i o n s of t h e I r i g a r a y s i t e began i n August, 1978.

The f a c i l i t y h a s t h e c a p a c i t y t o produce 500,000 l b / y of

uranium as U308.

Approximately 19 AF/y of ground water w i l l b e con-

sumed i n p r o d u c t i o n r e l a t e d p r o c e s s e s .

Well f i e l d p l a n s i n c l u d e develop-

ment of n i n e production u n i t s w i t h approximately 40 seven-spot p r o d u c t i o n c e l l s i n each u n i t .

The mining o p e r a t i o n w i l l u l t i m a t e l y

i n c l u d e 300 p r o d u c t i o n w e l l s , 800 i n j e c t i o n w e l l s , and 85 monitor w e l l s . S i x p r o d u c t i o n u n i t s have been f u l l y developed, w i t h u n i t s 7-9 c u r r e n t l y being d r i l l e d .

A maximum p r e s s u r e of 140 p s i a t t h e s u r f a c e i s used

t o inject the lixiviant.

R e s t o r a t i o n of t h e s i t e w i l l b e s i m i l a r t o t h e t e s t s i t e r e s t o r a t i o n procedure.

An e s t i m a t e d 130 AF of water w i l l b e consumed i n t h e

r e s t o r a t i o n of t h e 30-acre w e l l f i e l d .

An a l t e r n a t i v e i n j e c t i o n f l u i d was t e s t e d d u r i n g 1979-80 a t t h e Lrigaray s i t e .

S i t e r e s t o r a t i o n began i n March, 1980.

The a l t e r n a t i v e

l i x i v i a n t has sodium-bicarbonate composition, and w i l l b e used i n mining u n i t s 6 through 9. Excursion H i s t o r y

I n 1979, t h r e e shallow monitor w e l l s exceeded upper c o n t r o l l i m i t s f o r c o n d u c t i v i t y , a l k a l i n i t y , and c h l o r i d e .

They were placed on

e x c u r s i o n s t a t u s and overpumping of a d j a c e n t p r o d u c t i o n w e l l s was initiated.

The cause of t h e e x c u r s i o n s was determined t o be a l a r g e

number of f a u l t y w e l l c a s i n g s which allowed f o r t h e upward m i g r a t i o n of mining f l u i d s .

A l l c a s i n g s were examined and r e p a i r e d where necessary.

During t h e s p r i n g of 1980, t h e I r i g a r a y mine s i t e was i s s u e d an "Order t o Show Cause" by t h e U.S.

Nuclear Regulatory Commission due t o

r e p e a t e d shallow zone monitor w e l l e x c u r s i o n s .

L i x i v i a n t i n j e c t i o n was

ceased f o r one month and p r e v i o u s l y i n j e c t e d f l u i d s were r e c i r c u l a t e d . I n J u l y , 1980, a monitor w e l l exceeded upper c o n t r o l l i m i t s f o r t o t a l a l k a l i n i t y and c o n d u c t i v i t y , and was placed on e x c u r s i o n s t a t u s . A s t u d y of t h e geology of t h e a r e a was i n i t i a t e d d u r i n g summer,

1980, t o determine i f t h e repeated e x c u r s i o n s were a n i n d i c a t i o n t h a t t h e s i t e was a c t u a l l y u n s u i t a b l e f o r i n s i t u uranium mining.

The

r e s u l t s i n d i c a t e d t h e a r e a was s u i t a b l e f o r t h e i n s i t u mining procedure and t h e e x c u r s i o n s were r e l a t e d t o m i g r a t i o n of f l u i d s i n abandoned e x p l o r a t i o n h o l e s which had been improperly plugged.

Clean-up opera-

t i o n s involved l o c a t i n g , d r i l l i n g o u t , and cementing t h e e x p l o r a t i o n

holes.

Subsequent water samples taken from t h e monitor w e l l s have

shown improved water q u a l i t y . Luenberger S i t e (Research and Development, Commercial S c a l e Pending) The Luenberger mine s i t e i s l o c a t e d i n S e c t i o n s 1 3 and 1 4 , Township

34 North, Range 74 West, Converse County, Wyoming.

The t o t a l permitted

a r e a planned f o r commercial-scale mining covers 760 a c r e s w i t h an e s t i mated 150 a c r e s t o be d i s t u r b e d by mining a c t i v i t i e s .

The proposed

w e l l f i e l d covers 80 a c r e s and w i l l b e developed over I1 y e a r s . The uranium m i n e r a l i z a t i o n i s l o c a t e d i n t h e Lebo Member of t h e F o r t Union Formation, which i s interbedded f i n e - t o coarse-grained sandstone, s i l t s t o n e , c l a y s t o n e , and c o a l . t h e Luenberger s i t e .

There a r e two o r e bodies a t

The upper mineralized zone i s i n t h e "N" sand a t

a depth of 220 t o 270 f e e t below t h e s u r f a c e .

T o t a l t h i c k n e s s of t h e

"N" sand i s about 50 f e e t , and t h e uranium d e p o s i t i s from f i v e t o 20 f e e t t h i c k . gpd/ft

2

, porosity

700 g p d / f t . area.

The average p e r m e a b i l i t y of t h i s sandstone i s 14 i s 26 p e r c e n t , and t h e average t r a n s m i s s i v i t y i s

It c o n t a i n s 26 p e r c e n t of t h e minable o r e i n t h e permit

The "N" sand is o v e r l a i n by a c l a y s t o n e and i s s e p a r a t e d from

t h e lower h o s t sand by interbedded c l a y s t o n e and s i l t s t o n e . The lower ("M") sand l i e s approximately 320-390 f e e t below t h e surface.

Average t h i c k n e s s of t h e bed i s 50-60 f e e t w i t h t h e o r e

i n t e r v a l ranging from f i v e t o 20 f e e t .

The average p e r m e a b i l i t y ,

t r a n s m i s s i v i t y , and p o r o s i t y of t h e h o s t sandstone a r e 6.7 g p d / f t

410 g p d / f t , and 25 p e r c e n t , r e s p e c t i v e l y .

2

,

A 1 1 claystones within t h e

sequency have " n e g l i g i b l e " p e r m e a b i l i t i e s and low s t o r a g e c o e f f i c i e n t s ;

t h e r e f o r e , l e a k a g e through t h e c l a y s t o n e above and below t h e production zone i s considered unimportant. I n i t i a l r e s e a r c h and development t e s t i n g of t h e s i t e was i n A p r i l and May of 1979, w i t h two s i n g l e h o l e t e s t s u s i n g a sodium b i c a r b o n a t e lixiviant.

The p i l o t test was expanded i n January, 1980, w i t h t h e

a d d i t i o n of two f i v e - s p o t p a t t e r n s completed i n each of t h e o r e zones. The uranium e x t r a c t i o n p l a n t a s s o c i a t e d w i t h t h e t e s t a r e a h a s a c a p a c i t y of 100 gpm. R e s t o r a t i o n tests began i n J u l y , 1980, i n one of t h e test p a t t e r n s , and c u r r e n t l y a ground-water sweep method i s being t e s t e d .

If it

proves u n s u c c e s s f u l , produced water w i l l be r e c y c l e d through t h e r e v e r s e osmosis p r o c e s s and r e - i n j e c t e d . I n t h e proposed commercial-scale o p e r a t i o n s t h e 80-acre w e l l f i e l d would b e d i v i d e d i n t o e i g h t mining u n i t s ( s i x i n t h e "MIt sand and two i n t h e "N" s a n d ) , each u s i n g a f i v e - s p o t p a t t e r n .

An e s t i m a t e d 180

w e l l s , completed i n t h e "M" sand, would be d r i l l e d i n Unit 1. The proposed e x t r a c t i o n p l a n t w i l l have a flow c a p a c i t y of 2,000 gpm when mining and ground-water r e s t o r a t i o n a c t i v i t i e s a r e o p e r a t i n g concurrently.

The l i x i v i a n t u t i l i z e d i n t h e i n i t i a l t e s t w i l l a l s o be

i n j e c t e d d u r i n g commercial-scale o p e r a t i o n s . R e s t o r a t i o n of t h e 80 a c r e s w i l l b e accomplished by r e - i n j e c t i o n of produced w a t e r f o l l o w i n g c i r c u l a t i o n through a r e v e r s e osmosis u n i t . To p r e v e n t e x c e s s i v e drawdowns w i t h i n a mining u n i t d u r i n g r e s t o r a t i o n , w a t e r w i l l b e pumped from an unmined u n i t i n t h e same p r o d u c t i o n zone t o t h e u n i t being restored.

This water w i l l t h e n b e pumped o u t of t h e

u n i t being r e s t o r e d , r e c y c l e d through a r e v e r s e osmosis u n i t , and re-inj ected.

Nine Mile S i t e (Research and Development) The Nine Mile i n s i t u uranium s i t e i s l o c a t e d i n t h e

s%,

Section

35, and t h e N E ~ ,NWk, S e c t i o n 34, Township 35 North, Range 79 West, Natrona County, Wyoming.

The permitted mine a r e a covers 81.9 a c r e s .

The uranium o r e body a t t h i s s i t e l i e s i n t h e Teapot Sandstone Member of t h e Mesaverde Formation, a t a d e p t h of about 500 f e e t .

The Teapot

Member i s 30 t o 80 f e e t i n t h i c k n e s s a t t h e s i t e , c o n t a i n s 20 t o 35 Ore

f e e t of uranium o r e , and i s o v e r l a i n and u n d e r l a i n by s h a l e s .

zone p e r m e a b i l i t y averages 32.7 g p d / f t 2 , w i t h t r a n s m i s s i v i t i e s of 1,300 t o 3,800 g p d / f t .

P o r o s i t y averages 28 p e r c e n t .

bounding s h a l e s a r e less than 0.02 g p d / f t

2

P e r m e a b i l i t i e s of t h e

.

T e s t i n g a t t h e Nine Mile s i t e began i n November, 1976.

Three t e s t

p a t t e r n s were leached w i t h a s u l f u r i c a c i d l i x i v i a n t , a t - i n j e c t i o n r a t e s A f o u r t h test, u t i l i z i n g an a l k a l i n e l i x i v i a n t ,

of approximately 10 gpm. i s c u r r e n t l y underway.

w e l l s have been used.

A t o t a l of 15 i n j e c t i o n w e l l s and 10 production

E a r l y r e s t o r a t i o n a t t e m p t s involved prolonged

pumping of t h e test site.

L a t e r e f f o r t s involved l i m e n e u t r a l i z a t i o n ,

chemical c l e a n s i n g , and r e - i n j e c t i o n of produced f l u i d s .

Restoration

of t h e c u r r e n t t e s t s i t e i s expected t o r e q u i r e r e c i r c u l a t i o n of roughly 5 p o r e volumes of r e v e r s e osmosis t r e a t e d f l u i d . Excursion H i s t o r y An e x c u r s i o n of mining s o l u t i o n was noted a t t h e Nine Mile s i t e i n l a t e 1979, when s e v e r a l parameters exceeded upper c o n t r o l l i m i t s . The e x c u r s i o n problem was solved by i n c r e a s e d production r a t e s .

P e t e r s o n S i t e (Research and Development Pending) The proposed P e t e r s o n i n s i t u uranium s i t e l i e s i n t h e N E ~ ,NWk, S e c t i o n 35, and t h e S E ~ SW4, , S e c t i o n 26, Township 36 North, Range 73 West, Converse County, Wyoming.

The uranium-bearing sandstone a t t h e

P e t e r s o n s i t e l i e s 220 t o 260 f e e t below t h e s u r f a c e , averages 40 f e e t i n t h i c k n e s s , and c o n t a i n s a 5 t o 15 f o o t t h i c k m i n e r a l i z e d zone. The o r e sand i s o v e r l a i n and u n d e r l a i n by 30 f e e t and 170 f e e t , r e s p e c t i v e l y , of mudstone. the southeast.

S t r a t a a t t h e s i t e d i p about 2 degrees t o

Ore sandstone p e r m e a b i l i t y v a r i e s from 5 t o 1 5 g p d / f t

w i t h t r a n s m i s s i v i t i e s of 242 t o 372 g p d / f t . percent.

2

P o r o s i t y averages 27

No p e r m e a b i l i t i e s a r e a v a i l a b l e f o r t h e bounding s h a l e s ,

b u t a q u i f e r t e s t s on t h e o r e sand show no evidence f o r s i g n i f i c a n t leakage. T e s t i n g a t t h e P e t e r s o n s i t e , though n o t y e t approved, i s planned f o r March, 1981.

Twelve i n j e c t i o n w e l l s , f o u r production w e l l s , and

e i g h t monitor w e l l s a r e planned f o r t h e 1.6-acre

test site.

i n j e c t e d s o l u t i o n w i l l c o n t a i n 2,000 t o 5,000 mg/l NaCO 1,500 mg/l of O2 o r H202.

3'

The

and 300 t o

R e s t o r a t i o n w i l l i n v o l v e c l e a n s i n g and

r e - i n j e c t i o n of produced f l u i d s , and w i l l r e s u l t i n a n e t withdrawal of about 0.63 a c r e - f e e t of w a t e r . Reno Creek ISL P r o j e c t (Research and Development) Reno Creek i s l o c a t e d i n S e c t i o n s 27 and 28, Township 43 North, Range 72 West, Campbell County, Wyoming.

Research and development

o p e r a t i o n s began i n 1979, on a permitted a r e a of 39.32 a c r e s . The uranium d e p o s i t i s l o c a t e d w i t h i n a sandstone of t h e Wasatch Formation t h a t is about 200 f e e t below t h e s u r f a c e and confined by

,

mudstones.

Average s a n d s t o n e p o r o s i t y , p e r m e a b i l i t y , and t h i c k n e s s

a r e 28 p e r c e n t , 1.0 g p d / f t 2 , and 118 f e e t , r e s p e c t i v e l y . T e s t s i t e I included one f i v e - s p o t p a t t e r n c o n s i s t i n g of f o u r i n j e c t i o n w e l l s , one producing w e l l , and seven monitor w e l l s .

This

t e s t was scheduled t o l a s t two y e a r s and included t h e a d d i t i o n of two more f i v e - s p o t s .

A s u l f u r i c a c i d l e a c h was i n j e c t e d a t a r a t e of 40

gpm (10 gpm/well) and withdrawn a t 42 gpm.

Problems a r o s e i n March

of 1979, a f t e r t h r e e months of production, i n c l u d i n g a r i s e i n calcium l e v e l s and evidence of gypsum s c a l i n g t h a t r e s u l t e d i n a l o s s of production.

E f f o r t s t o r e s t o r e production were only semi-successful

and t h e uranium c o n t e n t of t h e produced f l u i d was c o n s i d e r a b l y lower than a n t i c i p a t e d .

Due t o s c a l i n g , fungus plugging, h i g h a c i d consump-

t i o n and t h e low U 0 c o n t e n t of produced f l u i d s , i t was concluded t h a t 3 8 a n a c i d l e a c h was u n s u c c e s s f u l a t Reno Creek. An addendum was f i l e d w i t h t h e Wyoming DEQ-LQD t o a l l o w f o r t h e d r i l l i n g of a second t e s t p a t t e r n ( t e s t s i t e 11) and t e s t i n g of a carbonate l i x i v i a n t .

This p a t t e r n was d r i l l e d i n September, 1979, and

i s c u r r e n t l y being t e s t e d .

The e x t r a c t i o n p l a n t has a production

c a p a c i t y of 35 t o 45 gpm. R e s t o r a t i o n of t h e i n i t i a l s i t e ( t e s t s i t e I) began i n November, 1979.

The method t e s t e d involved r e - i n j e c t i o n of c l e a n water from

treated leach solution.

Water was cleansed by lime n e u t r a l i z a t i o n ,

C02 a d d i t i o n , and e i t h e r barium hydroxide a d d i t i o n , i o n exchange, o r r e v e r s e osmosis.

A s of December 31, 1979, t h r e e pore volumes of c l e a n

water had been pumped through t h e p a t t e r n . R e s t o r a t i o n of test s i t e I1 w i l l be accomplished by r e - i n j e c t i n g produced water t h a t h a s been cycled through a r e v e r s e osmosis u n i t .

Ruth ISL S i t e (Research and Development Pending) The proposed Ruth ISL mine s i t e i s l o c a t e d i n t h e SE*, N E ~ ,S E ~ S , e c t i o n 1 4 , SWk,

NWk,

West, Johnson County, Wyoming.

N E ~ ,and

S e c t i o n 13, Township 27 North, Range 77 The o p e r a t i o n would i n c l u d e a permitted

a r e a of 39.94 a c r e s w i t h l e s s than 10 a c r e s d i s t u r b e d by mining activities. The t a r g e t sand is l o c a t e d i n t h e lower p a r t of t h e Wasatch Format i o n approximately 500 t o 565 f e e t below t h e s u r f a c e .

It i s p r i m a r i l y

a r k o s i c i n composition, w i t h s u b s t a n t i a l o r g a n i c d e b r i s , carbonaceous s t r i n g e r s , and l o c a l i z e d sandy s h a l e l e n s e s .

T o t a l t h i c k n e s s of t h e

sand u n i t , which is confined by s h a l e s , i s roughly 50 f e e t . T r a n s m i s s i v i t y of t h e o r e sandstone i s 141.9 g p d / f t and p o r o s i t y i s 29 p e r c e n t . The i n s i t u t e s t s i t e w i l l c o n t a i n f i v e seven-spot hexagonal p a t t e r n s i n c l u d i n g 19 i n j e c t i o n w e l l s and f i v e recovery w e l l s . a l k a l i n e carbonate-bicarbonate l i x i v i a n t w i l l b e t e s t e d .

An

The p i l o t

p r o c e s s i n g p l a n t h a s a planned maximum c a p a c i t y of 50 gpm. I n i t i a l r e s t o r a t i o n t e s t s w i l l i n v o l v e a ground-water sweep w i t h d i s p o s a l of recovered water i n t o s o l a r e v a p o r a t i o n ponds.

If this

method should prove u n s u c c e s s f u l , r e - i n j e c t i o n of water p u r i f i e d by r e v e r s e osmosis w i l l be t e s t e d . Pending DEQ-LQD a p p r o v a l , s i t e p r e p a r a t i o n , w e l l f i e l d d r i l l i n g , and p l a n t and pond c o n s t r u c t i o n w i l l b e g i n i n s p r i n g of 1981. p i l o t l e a c h test i s scheduled t o begin e a r l y summer, 1981.

The

Leaching

w i l l l a s t f o r 10 months, followed by f o u r months of s i t e r e s t o r a t i o n .

IV.

I N

S I T U

T R O N A

I N E C T I O N

P R O J E C T S Trona (Na2C03*NaHC0 *2H20), a h i g h l y s o l u b l e e v a p o r i t e mineral, 3 o c c u r s w i t h i n s a l i n e l a k e d e p o s i t s i n s e v e r a l p a r t s of t h e world, i n c l u d i n g t h e Sahara and K a l a h a r i D e s e r t s of A f r i c a , p a r t s of I r a n , Armenia, and T i b e t i n Asia, and C a l i f o r n i a and Wyoming i n t h e United States.

Trona i s used a s a raw source of p u r e sodium c a r b o n a t e (NaCO ) 3

o r soda a s h .

Major u s e s of soda a s h i n c l u d e g l a s s manufacture, sodium-

based chemical p r o d u c t i o n , and pulp and paper p r o c e s s i n g .

Roughly

1 2 m i l l i o n s h o r t t o n s of t r o n a were mined i n t h e United S t a t e s d u r i n g 1978; about 95 p e r c e n t of t h i s tonnage was produced i n Wyoming by c o n v e n t i o n a l s u b s u r f a c e mining methods (U.S.

Bureau of Mines, 1980).

The h i g h l y s o l u b l e n a t u r e of t r o n a h a s r a i s e d i n t e r e s t i n t h e p o s s i b l e i n s i t u recovery of t h i s r e s o u r c e .

No i n s i t u t r o n a recovery

p r o j e c t s were o p e r a t i o n a l w i t h i n Wyoming a s of mid-1981.

However, two

r e s e a r c h and development s c a l e t r o n a s o l u t i o n p r o j e c t s have been proposed, w i t h t h e t e s t p l a n s r e c e n t l y approved by t h e Wyoming Department of Environmental Quality-Land Q u a l i t y D i v i s i o n (DEQ-LQD).

The

f o l l o w i n g s e c t i o n s c o n t a i n d i s c u s s i o n s of (1) t h e c h a r a c t e r i s t i c s of t h e Wyoming t r o n a d e p o s i t s ; (2) t h e technology and p o t e n t i a l environmental impacts of i n s i t u t r o n a recovery; and (3) b r i e f d e s c r i p t i o n s of t h e two proposed r e s e a r c h and development t r o n a s o l u t i o n s i t e s .

IV- 1

CHARACTERISTICS OF THE WYOMING TRONA DEPOSITS The l a r g e s t known t r o n a d e p o s i t s i n e x i s t e n c e occur w i t h i n t h e Wilkins PeakMember of t h e Eocene Green River Formation, Sweetwater County, Wyoming.

Here, an a r e a of roughly 1,100 s q u a r e m i l e s i s under-

l a i n by bedded t r o n a .

The bulk of t h e d e p o s i t s a r e contained i n 25

o r more major beds ranging from about 3 t o 40 f e e t i n t h i c k n e s s (Bradley and E u g s t e r , 1969), and l y i n g from 1,500 t o 2,000 f e e t below the surface.

Extent of t h e i n d i v i d u a l beds varies from less than 165

square m i l e s t o over 723 square m i l e s .

Thinner t r o n a l a y e r s , up t o

2 f e e t i n t h i c k n e s s , a r e p r e s e n t between t h e major beds and a r e of uncertain extent.

Dolomitic mudstones and s h a l e s , some h i g h i n o r g a n i c

m a t t e r , a r e interbedded w i t h t h e t r o n a d e p o s i t s . Associated w i t h t h e Wilkins Peak t r o n a d e p o s i t s a r e o t h e r e v a p o r i t e m i n e r a l s , i n c l u d i n g c o n s i d e r a b l e amounts of s h o r t i t e (Na CO .CaCO -2H20), 3 2 3 northrupite

(Na2C03*MgC03-NaCl) ,

and h a l i t e (NaC1).

Detailed a n a l y s i s

of a 555-foot c o r e of t h e Wilkins Peak member (Section 2, Township 1 8 North, Range 110 West) by Fahey ( l 9 6 2 ) , i n d i c a t e s i t contained 10 p e r c e n t s h o r t i t e , 6.4 p e r c e n t t r o n a , and 2.2 p e r c e n t n o r t h r u p i t e .

In general,

only t r o n a and o c c a s i o n a l l y h a l i t e a r e p r e s e n t a s d i s t i n c t beds, a l t h o u g h e x c e p t i o n s e x i s t (Bradley and E u g s t e r , 1969). For a more d e t a i l e d d e s c r i p t i o n of Wilkins Peak m i n e r a l o g i e s , s e e Fahey (1962) and Bradley and Eugster (1969)

.

REVIEW OF CURRENT TECHNOLOGIES

L i t t l e p u b l i s h e d i n f o r m a t i o n i s a v a i l a b l e concerning t h e techn o l o g i c a l a s p e c t s of i n s i t u t r o n a recovery.

Although o t h e r bedded

e v a p o r i t e d e p o s i t s , p a r t i c u l a r l y h a l i t e , have been s o l u t i o n a l l y mined

IV- 2

s i n c e t h e 1940's (Bay, 1962), i n s i t u t r o n a recovery h a s y e t t o be tested in the field.

Two r e s e a r c h and development t r o n a s o l u t i o n

p r o j e c t s , proposed f o r Sweetwater County, Wyoming, have r e c e n t l y been approved by t h e state.

Much of t h e t e c h n o l o g i c a l a s p e c t s of t h e s e

t e s t s i s c o n s i d e r e d c o n f i d e n t i a l by t h e mine o p e r a t o r s .

Therefore t h e

f o l l o w i n g s e c t i o n s a r e based l a r g e l y upon p o r t i o n s of t h e t e s t p l a n s f o r t h e above s i t e s which a r e n o t considered p r o p r i e t a r y information, and a r e on open f i l e a t t h e Wyoming DEQ-LQD.

A d d i t i o n a l l y , some

a n a l o g i e s a r e drawn between t r o n a and bedded h a l i t e s o l u t i o n mining t e c h n i q u e s , because of t h e l a r g e amount of a v a i l a b l e d a t a on i n s i t u h a l i t e p r o c e s s e s and t h e s i m i l a r g e o l o g i c a l and geochemical c h a r a c t e r i s t i c s of t h e s e m i n e r a l s . The b a s i c methodology of i n s i t u t r o n a mining i s f a i r l y simple. A p a i r of w e l l s , one designed f o r f l u i d i n j e c t i o n and one f o r b r i n e

p r o d u c t i o n , a r e completed i n t h e t r o n a d e p o s i t .

An e f f i c i e n t spacing

d i s t a n c e between t h e i n j e c t i o n l p r o d u c t i o n w e l l s i s c u r r e n t l y unknown. The proposed test sites w i l l u t i l i z e a 350 t o 450 f o o t spacing (Wyoming DEQ-LQD,information f i l e s , 1981).

A commercial-scale t r o n a s o l u t i o n

mine would l i k e l y u t i l i z e g r e a t e r s e p a r a t i o n s ; w e l l s p a c i n g s a t a c t i v e h a l i t e s o l u t i o n mines a r e g e n e r a l l y between 500 and 1,500 f e e t (Bay, 1962). Following w e l l completions t h e i n j e c t i o n / p r o d u c t i o n w e l l s a r e hydrologically linked.

The proposed t r o n a test s i t e s w i l l a t t e m p t

l i n k a g e through h y d r o f r a c t u r i n g .

I n j e c t i o n p r e s s u r e needed f o r i n i t i a l

f r a c t u r i n g i s expected t o be l e s s than 3,500 l b / i n 2 (Wyoming DEQ-LQD, information f i l e s , 1981).

Data from h a l i t e s o l u t i o n mines where

h y d r o f r a c t u r i n g h a s been employed i n d i c a t e i n j e c t i o n p r e s s u r e s of about 2,500 l b / i n

2

a r e r e q u i r e d , a t s i m i l a r d e p t h s (Mair, 1960).

Solution

passage development i n h a l i t e , and l i k e l y i n t r o n a a s w e l l , t e n d s t o f o l l o w t h e zones of weakness induced by h y d r o f r a c t u r i n g ; t h e r e f o r e d i r e c t i o n a l w e l l p e r f o r a t i o n and/or formation "notching" i s o f t e n employed t o i n s u r e proper s o l u t i o n passage growth from t h e i n j e c t i o n

w e l l t o t h e p r o d u c t i o n w e l l (Henderson, 1962).

A s a t u r a t e d b r i n e solu-

t i o n i s used f o r i n t h e i n i t i a l f r a c t u r i n g t o c o n t r o l c a v i t y development adjacent the injection w e l l .

Other w e l l l i n k i n g techniques employed

a t h a l i t e s o l u t i o n mines, and which may b e s u i t a b l e f o r t r o n a d e p o s i t s , a r e d i r e c t i o n a l d r i l l i n g and b l a s t i n g . When t h e i n j e c t i o n / p r o d u c t i o n w e l l s a r e s u c c e s s f u l l y l i n k e d , a c t i v e s o l u t i o n mining commences.

A h e a t e d , water based s o l v e n t i s introduced

i n t o t h e d e p o s i t through t h e i n j e c t i o n w e l l , and t h e r e s u l t i n g b r i n e

i s withdrawn through t h e p r o d u c t i o n w e l l , conveyed t o shallow ponds, and t h e t r o n a is r e d e p o s i t e d through e v a p o r a t i o n .

Temperature of t h e

i n j e c t e d s o l v e n t i s dependent upon h e a t l o s s t o t h e formation, b u t i s expected t o b e less t h a n 180°F a t t h e Wyoming test s i t e s (Wyoming DEQLQD, i n £ormation f i l e s , 1981).

Composition of t h e i n j e c t e d s o l v e n t i s

c o n s i d e r e d c o n f i d e n t i a l by t h e mine o p e r a t o r s .

The s o l v e n t i s l i k e l y

u t i l i z e d t o i n s u r e t h a t a s t h e sodium c o n c e n t r a t i o n of t h e b r i n e increases,sodium b i c a r b o n a t e and sodium c a r b o n a t e m i n e r a l s , which have d i f f e r i n g s o l u b i l i t i e s depending upon temperature and p a r t i a l p r e s s u r e of C02, remain u n s t a b l e a s s o l i d phases. Active s o l u t i o n mining c o n t i n u e s u n t i l recovery i s no longer economic.

I f no f l u i d l o s s e s a r e t a k i n g p l a c e when mining c e a s e s , t h e

c a v i t y i s f i l l e d w i t h s a t u r a t e d b r i n e , a s support a g a i n s t roof c o l l a p s e .

Due t o t h e low p e r m e a b i l i t y of t r o n a , no r e s t o r a t i o n a c t i v i t i e s a r e proposed (Wyoming DEQ-LQD,

information f i l e s , 1981).

POTENTIAL ENVIRONMENTAL IMPACTS P o t e n t i a l environmental impacts a s s o c i a t e d w i t h i n s i t u t r o n a recovery i n c l u d e e x c u r s i o n s of t h e i n j e c t e d s o l v e n t o r produced b r i n e i n t o o v e r l y i n g o r underlying a q u i f e r s , and subsidence problems a s t h e s o l u t i o n a l l y mined c a v i t y grows.

These e f f e c t s a r e d i s c u s s e d below.

Excursions of s o l v e n t and/or b r i n e a r e considered u n l i k e l y during t h e normal course of s o l u t i o n mining due t o t h e low primary p e r m e a b i l i t y i n trona deposits.

Hydrofracturing of t h e d e p o s i t s r e s u l t s i n g r e a t l y

i n c r e a s e d p e r m e a b i l i t y , b u t p r e s s u r e g r a d i e n t s induced by t h e i n j e c t i o n / production w e l l p a i r would l i k e l y r e s t r i c t flow t o t h e a r e a between t h e wells.

Excursion problems could a r i s e i f h y d r o f r a c t u r i n g a f f e c t s over-

o r under-lying

s t r a t a , opening a p a t h f o r b r i n e escape.

The p o t e n t i a l

f o r such b r i n e l o s s may be e v a l u a t e d p r i o r t o mining, by c i r c u l a t i n g a s a t u r a t e d s o l u t i o n through t h e i n j e c t i o n / p r o j e c t i o n w e l l p a i r . S a t u r a t e d b r i n e cannot cause c a v i t y growth; t h e r e f o r e i f i n j e c t i o n and production volumes a r e e q u a l , no f l u i d l o s s i s t a k i n g p l a c e (Wyoming DEQ-LQD,

i n £ormation f i l e s , 1981).

A commercial s c a l e t r o n a s o l u t i o n mine may cause roof c o l l a p s e o r even s u r f a c e subsidence, depending upon t h e s i z e , shape, and depth of t h e produced c a v i t y .

While such problems cannot be a l l e v i a t e d

e n t i r e l y , s e v e r a l methods of l i m i t e d c o l l a p s e , such a s a r e employed a t h a l i t e s o l u t i o n mines, a r e a p p l i c a b l e t o t r o n a .

These include:

(1)

planned c a v i t y development w i t h a minimum of roof exposure; ( 2 ) monitor of c a v i t y development by m a t e r i a l removal monitoring and sonar

i n v e s t i g a t i o n s ; (3) s u r f a c e and subsurface monitoring f o r e a r t h movements; and (4) s a t u r a t e d b r i n e f i l l i n g of t h e c a v i t y when mining c e a s e s . A SITES PHYSICAL DESCRIPTIONS OF I N SITU TRO-NInformation used f o r i n s i t ~ t r o n a s i t e d e s c r i p t i o n s i s taken from mine t e s t p l a n s submitted t o t h e Wyoming DEQ-LQD.

Much of t h e i n f o r -

mation on one of t h e s e s i t e s i s considered c o n f i d e n t i a l by t h e mine o p e r a t o r ; i t s d e s c r i p t i o n i s l i m i t e d t o l o c a t i o n only.

Vulcan M a t e r i a l s Vulcan M a t e r i a l s , I n c . , w i l l t e s t i n s i t u t r o n a recovery a t a 10-acre s i t e l o c a t e d w i t h i n Section 1 6 , Township 16 North, Range 109 West.

The evaporite-bearing s e c t i o n of t h e Wilkins Peak Member l i e s

1,650 t o 2,026 f e e t below t h e s u r f a c e a t t h e s i t e . a r e interbedded w i t h mudstones and o i l s h a l e s .

The t r o n a d e p o s i t s

D r i l l s t e m t e s t perme-

a b i l i t i e s of t h e interbedded mudstones vary from 0.0045 t o 0.02 g p d / f t

2

.

T e s t s a t t h e Vulcan M a t e r i a l s s i t e w i l l u t i l i z e one i n j e c t i o n / production w e l l p a i r , spaced a t about 350 t o 450 f e e t .

w i l l be used t o h y d r o l o g i c a l l y connect t h e w e l l p a i r . i s expected t o be less than 3,500 l b / i n

2

.

Hydrofracturing Fracture pressure

Elevated h y d r a u l i c p r e s s u r e

w i l l be maintained a f t e r t h e i n i t i a l f r a c t u r e t o i n s u r e hydrologic

connection, and t o s o l u t i s n a l l y widen t h e p a t h between t h e w e l l s . Once w e l l l i n k a g e i s accomplished, s a t u r a t e d b r i n e w i l l b e c i r c u l a t e d through t h e system f o r about one week, a t 50 gpm, t o d e t e c t any fluid losses.

T h i s phase of t e s t i n g w i l l be followed by i n j e c t i o n of

h o t w a t e r , a t temperatures up t o 180°F, t o determine h e a t l o s s e s .

The

f i n a l t e s t i n g phase w i l l involve i n j e c t i o n of a heated s o l v e n t s o l u t i o n

t o determine t h e f e a s i b i l i t y of t r o n a s o l u t i o n mining.

Composition of

t h e i n j e c t e d s o l v e n t i s considered c o n f i d e n t i a l by t h e mine o p e r a t o r . F e a s i b i l i t y t e s t i n g i s expected t o l a s t f o u r t o s i x weeks. FMC FMC, which h a s long mined t r o n a by conventional s u b s u r f a c e methods, w i l l test i n s i t u t r o n a recovery a t a s i t e w i t h i n S e c t i o n 3 6 , Township

1 7 North, Range 110 West.

D e t a i l s of t h i s t e s t a r e considered c o n f i -

d e n t i a l by the o p e r a t o r .

IV- 7

V.

U N D E R G R O U N D

G A S I F I C A T I O N

COAL

P R O J E C T S

The process of underground g a s i f i c a t i o n of c o a l t o methane, though f a c i n g t e c h n i c a l d i f f i c u l t i e s and n o t c u r r e n t l y a p p l i e d on a commercial s c a l e i n t h e United S t a t e s , may someday provide an economically f e a s i b l e method f o r e x p l o i t i n g t h e deeply buried c o a l s of t h e American West. Underground c o a l g a s i f i c a t i o n (UCG) i s n o t a new concept; a s e a r l y a s 1868, g a s i f i c a t i o n of s l a c k and waste c o a l remaining i n mineshafts was suggested.

During t h e 1930's s e v e r a l UCG techniques were developed

i n t h e Soviet Union, and one commercial-scale f a c i l i t y was brought i n t o operation.

Experimental work w i t h UCG i n t h e United S t a t e s began i n

t h e l a t e 1940's under t h e d i r e c t i o n of t h e U.S.

Bureau of Mines and

c o n t i n u e s today through t h e U.S. Department of Energy.

A general dis-

cussion of t h e UCB process and p o t e n t i a l environmental e f f e c t s i s given below.

For a more d e t a i l e d treatment of UCG technology, s e e

"Environmental Aspects of Coal Conversion" (Oak Ridge N a t i o n a l Laboratory, 1977).

REVIEW OF CURRENT TECHNOLOGIES Underground c o a l g a s i f i c a t i o n c o n s i s t s of c o a l seam combustion, aided by inflowing oxygen, a i r , o r a i r and steam, followed by t h e c o l l e c t i o n of produced gases.

Early work by t h e Russians involved

e x t e n s i v e mechanical development of t h e c o a l seam, such a s digging o r b l a s t i n g t u n n e l s f o r enhancement of combustant/product gas flow, and f o r i s o l a t i o n of t h e c o a l p a n e l s t o be g a s i f i e d .

While t h e s e methods

provided a f a i r degree of s u c c e s s , economic c o n s i d e r a t i o n s l i m i t t h e i r a p p l i c a b i l i t y t o shallow d e p o s i t s .

UCG experiments i n t h e United

S t a t e s have emphasized borehole methods, e l i m i n a t i n g t h e need f o r mechanical p r e - g a s i f i c a t i o n

seam development.

Although s p e c i f i c s of b o r e h o l e g a s i f i c a t i o n methods v a r y , t h e p r o c e s s e s a r e g e n e r a l l y similar.

P a i r s of b o r e h o l e s , one f o r i n j e c t i o n

and one f o r p r o d u c t i o n , a r e d r i l l e d i n t o t h e c o a l seam.

These, o r o t h e r

w e l l s , may b e used t o dewater t h e seam i f dewatering i s deemed necessary. Coal seam p e r m e a b i l i t y between t h e i n j e c t i o n / p r o d u c t i o n w e l l s i s o f t e n i n c r e a s e d by h y d r o f r a c t u r i n g , d i r e c t i o n a l d r i l l i n g , e x p l o s i v e s , o r e l e c t r o c a r b o n i z a t i o n ( p a s s i n g s u f f i c i e n t e l e c t r i c c u r r e n t through t h e seam t o h e a t t h e c o a l t o d i s t i l l a t i o n and coking temperatures and inducing f r a c t u r i n g ) .

A f t e r t h e seam i s i g n i t e d n e a r one of t h e bore-

h o l e s , a combustant i s i n j e c t e d i n t o t h e seam t h a t c o n t r o l s t h e burn r a t e and d r i v e s t h e f i r e f a c e through t h e seam.

Injection pressures

a r e usually equal t o o r g r e a t e r than t h e e x i s t i n g hydrostatic pressure, t o l i m i t i n t r u s i o n of ground water.

Occasionally, high i n i t i a l

i n j e c t e d p r e s s u r e s may b e used f o r dewatering purposes.

The d i r e c t i o n

of f i r e f a c e movement through t h e seam may b e e i t h e r h o r i z o n t a l o r vertical.

Combustion may b e i n t h e same d i r e c t i o n a s t h e g a s flow,

c a l l e d forward combustion, o r o p p o s i t e t o t h e g a s flow, termed r e v e r s e combustion. F a c t o r s a f f e c t i n g t h e e f f i c i e n c y of UCG experimental developments include:

(1) g a s leakage o u t of t h e combustion zone; ( 2 ) u n c o n t r o l l e d

i n t r u s i o n of ground w a t e r i n t o t h e combustion zone; ( 3 ) i n a b i l i t y t o c o n t r o l t h e burn d i r e c t i o n and r a t e ; (4) l o s s of c o a l seam f r a c t u r e p e r m e a b i l i t y due t o plugging w i t h c o a l t a r s and o t h e r heavy l i q u i d

g a s i f i c a t i o n by-products;

and (5) f a i l u r e t o e s t a b l i s h a s u f f i c i e n t l y

permeable l i n k a g e between i n j e c t i o n / p r o d u c t i o n w e l l p a i r s (Oak Ridge N a t i o n a l Laboratory, 1977; Campbell and o t h e r s , 1974; Gregg and o t h e r s , 1976).

POTENTIAL ENVIRONMENTAL IMPACTS I n s i t u c o a l g a s i f i c a t i o n o f f e r s s e v e r a l environmental advantages over conventional e x t r a c t i o n methods.

Acid d r a i n a g e , d i s t u r b a n c e of

overburden and t h e mine a r e a land s u r f a c e , and o t h e r impacts of s t r i p mining a r e avoided, a s a r e t h e p o t e n t i a l h e a l t h dangers a s s o c i a t e d w i t h underground c o a l mining.

However, t h e magnitude of environmental

e f f e c t s of a l a r g e UCG p r o j e c t a r e poorly known, due t o t h e p r e s e n t l a c k of commercial-scale development. I n v e s t i g a t i o n s a t r e s e a r c h and development s i t e s have i d e n t i f i e d s e v e r a l f e a t u r e s of t h e UCG process t h a t may l e a d t o l o c a l groundwater d e g r a d a t i o n , i n c l u d i n g :

(1) escape of g a s i n t o a d j a c e n t p o r t i o n s

of t h e c o a l and/or o v e r l y i n g s t r a t a , i n c r e a s i n g t h e c o n c e n t r a t i o n of d i s s o l v e d o r g a n i c s i n a r e a ground w a t e r s ; (2) l e a c h i n g of r e s i d u a l m a t e r i a l s remaining i n t h e burn zone following combustion, l e a d i n g t o i n c r e a s e d downgradient c o n c e n t r a t i o n s of t r a c e elements, o r g a n i c s , and d i s s o l v e d s o l i d s ; and ( 3 ) subsidence of overlying s t r a t a due t o c o a l combustion, producing a h y d r a u l i c connection between t h e combustion zone and overlying ground-water s o u r c e s .

Combust ion Gas Leakage Gas l o s s t o zones a d j a c e n t t o t h e burn o f t e n i s g r e a t e r than 10 p e r c e n t of t o t a l g a s production (Oak Ridge National Laboratory, 1977). While produced gas composition i s v a r i a b l e , t h e gas g e n e r a l l y c o n t a i n s

'V-3

a complex m i x t u r e of v o l a t i l e o r g a n i c compounds; a n a l y s i s of steam produced d u r i n g an i n s i t u g a s i f i c a t i o n t e s t n e a r G i l l e t t e , Wyoming (Hoe Creek s i t e ) i d e n t i f i e d over 250 d i f f e r e n t o r g a n i c compounds, w i t h g r e a t e r t h a n 1 mg/l c o n c e n t r a t i o n s of condensed a c e t o n e , benzene, t o l u e n e , and naphalene.

D i s p e r s i o n of t h e s e v o l a t i l e o r g a n i c s i n t o

a d j a c e n t zones is c o n t r o l l e d by molecular weight, w i t h l i g h t e r compounds m i g r a t i n g f a r t h e r from t h e burn than r e l a t i v e l y h e a v i e r compounds (Campbell and o t h e r s , 1979).

E f f e c t s of Combustion Zone Leaching Leaching of c o a l t a r s , a s h , and o t h e r by-products of g a s i f i c a t i o n remaining i n t h e burn zone t a k e s p l a c e a f t e r burn zone temperatures have f a l l e n below 1 0 0 ° ~ . Monitoring of Lawrence Livermore ~ a b o r a t o r y ' s UCG p i l o t p r o j e c t n e a r G i l l e t t e , Wyoming, showed t h a t c o a l seam ground

w a t e r s p a s s i n g through t h e burn zone contained i n c r e a s e d c o n c e n t r a t i o n s of d i s s o l v e d s o l i d s , major i o n s , l i t h i u m , cyanide, bromide, p h e n o l i c m a t e r i a l s , and t r a c e m e t a l s , r e l a t i v e t o b a s e l i n e c o n d i t i o n s (Mead and o t h e r s , 1978).

Elevated c o n c e n t r a t i o n s of t r a c e metals diminished

r a p i d l y w i t h d i s t a n c e from t h e burn zone.

Laboratory evidence i n d i c a t e s

t h a t a d s o r p t i o n of metal i o n s onto c o a l was r e s p o n s i b l e f o r t h e observed d e c r e a s e (Wang, 1979). Though h i g h t r a c e metal c o n c e n t r a t i o n s were l i m i t e d t o a r e a s a d j a c e n t t o t h e burn, s u b t l e i n c r e a s e s i n o t h e r i n o r g a n i c , n o n v o l a t i l e s p e c i e s were noted a s f a r a s 100 f e e t from t h e burn zone w i t h i n t h r e e days a f t e r combustion ceased.

Mead and o t h e r s (1978) suggested t h a t

t h i s r a p i d movement i s caused by convection c u r r e n t s , induced by temperature d i f f e r e n t i a l s e x i s t i n g a c r o s s t h e burn boundary.

Long-term

(25 months) monitoring showed c o n c e n t r a t i o n s of most combustion r e l a t e d contaminants t o d e c r e a s e s i g n i f i c a n t l y w i t h time, though n o t t o b a s e l i n e levels.

Decreases were a s c r i b e d t o a l o s s of convective c u r r e n t s and

a lowering of s o l u b i l i t i e s a s t h e burn zone cools.

Overburden Subsidence Where l a r g e t h i c k n e s s e s of c o a l a r e removed, s i g n i f i c a n t roof c o l l a p s e i s l i k e l y t o occur, p o t e n t i a l l y allowing f o r movement of gases and contaminated burn zone w a t e r s i n t o o v e r l y i n g s t r a t a .

If

l a r g e - s c a l e subsidence o c c u r s , shallow flow systems may be t o t a l l y disrupted.

The e f f e c t s of subsidence-induced h y d r a u l i c connection

between t h e c o a l a q u i f e r and o v e r l y i n g a q u i f e r s a r e h i g h l y s i t e s p e c i f i c and l i k e l y dependent upon:

(1) t h e r e l a t i v e h y d r a u l i c head d i f f e r e n c e s

i n t h e c o a l and o v e r l y i n g a q u i f e r s ; ( 2 ) t h e hydrochemical and e l e c t r o chemical c o n d i t i o n s of o v e r l y i n g ground w a t e r s ; ( 3 ) t h e presence o r absence of adsorbing m a t e r i a l s i n overlying s t r a t a ; (4) e f f e c t s of convective c u r r e n t s o r i g i n a t i n g i n t h e burn zone; and ( 5 ) t h e a r e a l e x t e n t of subsidence.

Although subsidence h a s occurred a t s e v e r a l

r e s e a r c h and development UCG s i t e s , environmental e f f e c t s of t h i s phenomenon a r e n o t p r e s e n t l y documented.

Development on a commercial

s c a l e may r e s u l t i n s i g n i f i c a n t subsidence over a r e l a t i v e l y l a r g e geographic a r e a . PHYSICAL DESCRIPTIONS OF UNDERGROUND COAL GASIFICATION SITES The following s e c t i o n d e s c r i b e s t h e hydrogeology and developmental h i s t o r y of UCG s i t e s w i t h i n Wyoming.

A s of l a t e 1980, t h r e e r e s e a r c h

and development UCG s i t e s , operated d i r e c t l y by o r under t h e d i r e c t i o n

'V-5

of t h e U.S. Department of Energy, e x i s t e d w i t h i n Wyoming:

t h e Hanna,

Hoe Creek, and North Knob UCG experiments.

Hanna S i t e The Hanna UCG s i t e l i e s i n t h e s W ~ , S e c t i o n 29 and t h e SE%, S e c t i o n 30, Township 22 North, Range 8 1 West, Carbon County, Wyoming.

The

d e p o s i t being e x p l o i t e d a t t h i s s i t e i s t h e sub-bituminous Hanna #1 c o a l of t h e Hanna Formation. 450 f e e t a t t h e s i t e .

Depths t o t h e c o a l seam v a r y from 275 t o

Seam t h i c k n e s s v a r i e s from 26 t o 30 f e e t .

Four UCG t e s t s have been completed a t t h e Hanna s i t e , beginning i n 1973.

I n a l l t e s t s , r e v e r s e combustion was used t o l i n k t h e

i n j e c t i o n l p r o d u c t i o n w e l l p a i r s , and a i r was u t i l i z e d a s t h e i n j e c t e d combustant. Hanna t e s t s 1-111 w e r e considered s u c c e s s f u l , b u t Hanna I V , designed t o t e s t t h e f e a s i b i l i t y of commercial-scale ( g r e a t e r t h a n 100 f e e t ) p r o c e s s w e l l s p a c i n g s , f a i l e d due t o an i n a b i l i t y t o e s t a b l i s h a s u s t a i n e d burn between t h e i n j e c t i o n / p r o d u c t i o n w e l l p a i r . problem was l i n k e d t o a f a u l t y w e l l completion.

The

Although t h e w e l l was

r e p a i r e d and a d d i t i o n a l p r o c e s s w e l l s were added t o t h e o r i g i n a l p a t t e r n , a s u s t a i n e d burn was n o t a t t a i n e d , and t h e Hanna I V t e s t was abandoned, Production r e l a t e d d e t a i l s of t h e Hanna t e s t s a r e given i n Table V-1.

For a more d e t a i l e d d i s c u s s i o n of t h e Hanna s i t e and a s s o c i a t e d

UCG t e s t i n g , see Bartke and o t h e r s (1980).

Table V-1.

U.S. Department of Energy

-

Hanna S i t e T e s t s .

Average Gas

4,000

-

17

Air Air Air

1,260 2,520 4,200

83% 89% 7 6%

2 4 4

52.5 60.0 60.0

Air

2,850

7 6%

2

60

Air

-

-

8

100-150'

t ) (BTU/~

180

126

1,600,000

Air

Hanna 11-1 11-2 11-3

38 25 38

152 175 138

2,700,000 8,500,000 12,000,000

Hanna 111

38

138

10,000,000

Hanna I

-4

Process a Efficiency

Number of I n je c tion/ Production Wells

Duration (days)

Test

-7

Average Production Rate (f t3/day)

Qua1it3

Hanna I V

a

Combust a n t

Coal Gasified (tons)

Process e f f i c i e n c y r e f e r s t o t h e energy v a l u e of t h e g a s c o l l e c t e d r e l a t i v e t o t h e energy v a l u e of t h e c o a l seam volume g a s i f i e d .

b ~ u s t a i n e dg a s i f i c a t i o n n o t maintained i n Hanna I V t e s t . C

Well Spacing (ft)

Spacing of o r i g i n a l t h r e e w e l l s . spacings.

Process r e l a t e d problems r e s u l t e d i n a d d i t i o n a l w e l l s a t v a r i o u s

Hoe Creek S i t e The Hoe Creek UCG s i t e i s l o c a t e d i n S e c t i o n 7 , Township 47 North, Range 72 West, Campbell County, Wyoming.

The c o a l being e x p l o i t e d a t

t h i s s i t e is t h e sub-bituminous F e l i x I1 c o a l of t h e Wasatch Formation. The F e l i x I1 c o a l averages 25 f e e t i n t h i c k n e s s , and l i e s about 125 f e e t below t h e land s u r f a c e a t t h i s s i t e . c o a l a r e s i l t s t o n e s and c l a y s t o n e s . 3.7 t o 7.3 g p d / f t

2

Overlying and underlying t h e

Coal seam p e r m e a b i l i t y v a r i e s from

.

Three UCG t e s t s have been completed a t Hoe Creek, under t h e d i r e c t i o n of Lawrence Livermore Laboratory, Livermore, C a l i f o r n i a . Test I was a small-scale,

s h o r t d u r a t i o n experiment.

Explosives.were

used t o enhance p e r m e a b i l i t y between process w e l l s , and a i r was u t i l i z e d a s t h e i n j e c t e d combustant.

Test I 1 a l s o employed a i r as t h e

combustant; process w e l l s were l i n k e d by r e v e r s e combustion.

In test

111, d i r e c t i o n a l d r i l l i n g was used t o l i n k t h e boreholes, and 0 /steam

2

was t h e i n j e c t e d oxidant.

Coal g a s of an average q u a l i t y g r e a t e r

3 than 200 B T U / £ ~ was produced d u r i n g t h e 47-day 02/steam t e s t . Production r e l a t e d d e t a i l s of t h e Hoe Creek UCG t e s t s a r e given i n Table V-2.

For a more d e t a i l e d d i s c u s s i o n of t h e Hoe Creek s i t e

and a s s o c i a t e d UCG t e s t i n g , s e e F i s h e r and Aiman (1978).

Table V-2.

U.S. Department of Energy

Average Gas Duration Test

Hoe Creek S i t e T e s t s

Average Product i o n Rate (ft3/day)

Combustant

Process E££ i c i e n c y a

Number of 1nj e c t i o n / Production Wells

120

73%

2

30

68%

2 2

60 60

Coal Gasified (tons)

Hoe Creek I

11

110

1,700,000

Air

Hoe Creek I1

58 2

106 263

3,300,000

Air 0 /steam 2

2,300

-

-

7 47

115 218

Air 0 /steam 2

260 3,900

-

Hoe Creek I11

7

)

-

-

Well Spacing (ft)

-

a Process e f f i c i e n c y r e f e r s t o t h e h e a t i n g v a l u e of t h e gas c o l l e c t e d r e l a t i v e t o t h e energy v a l u e of t h e c o a l seam volume g a s i f i e d .

North Knob S i t e The North Knob UCG s i t e i s l o c a t e d w i t h i n S e c t i o n 11, Township 21 North, Range 89 West, Carbon County, Wyoming.

The d e p o s i t being

e x p l o i t e d a t North Knob i s t h e sub-bituminous G c o a l seam of t h e F o r t Union Formation.

The G c o a l is about 23 f e e t t h i c k a t t h e s i t e , and

d i p s a t 63 d e g r e e s t o t h e southwest. from 0 f e e t t o 600 f e e t .

Depth t o t h e c o a l seam v a r i e s

Coal seam p e r m e a b i l i t y is less than 0 . 1

The North Knob s i t e was s e l e c t e d f o r r e s e a r c h i n t o t h e f e a s i b i l i t y of i n s i t u g a s i f i c a t i o n of s t e e p l y dipping c o a l beds.

One UCG t e s t

h a s been conducted a t North Knob, a s a j o i n t v e n t u r e between t h e U.S. Department of Energy and Gulf Research and Development Corporation. The i n j e c t i o n / p r o d u c t i o n w e l l p a i r used a t North Knob was l i n k e d by d i r e c t i o n a l d r i l l i n g .

A i r was employed a s t h e combustant throughout

most of t h e t e s t , a l t h o u g h 0 /steam was u t i l i z e d f o r a s h o r t p a r t of 2 t h e experiment.

Both t h e a i r and 02/steam t e s t s y i e l d e d s u c c e s s f u l

results. Production r e l a t e d d e t a i l s of t h e North Knob t e s t a r e given i n Table V-3.

For a more d e t a i l e d d i s c u s s i o n of t h e North Knob s i t e

and a s s o c i a t e d UCG t e s t i n g , s e e Gulf Research and Development Corporation (1980).

Table V-3.

U.S. Department of EnergylGulf Research and Development Corp.

Average Gas Duration Test North Knob I a

7

P I-'

)

38

167

Average Product i o n Rate (f t3/day)

Combustant

Coal Gasif l e d (tons)

-

Air

1,200

- North Knob S i t e T e s t s

Process ~f f i c i e n c y a

75%

Number of 1 n je c t i o n / Production Wells

Well Spacing (ft)

2

100

a P r o c e s s e f f i c i e n c y r e f e r s t o t h e h e a t i n g v a l u e of t h e g a s c o l l e c t e d r e l a t i v e t o t h e energy v a l u e of t h e c o a l seam volume g a s i f i e d .

CHEMICAL

VI.

I N J E C T I O N

WASTE S I T E S

A s of l a t e 1980, only one chemical waste d i s p o s a l w e l l was o p e r a t i o n a l w i t h i n Wyoming.

The w e l l i s l o c a t e d i n t h e sW%,

sW~,

S e c t i o n 1 6 , Township 1 3 North, Range 67 West, Laramie County, and i s operated by Wycon Chemical Corporation.

T o t a l w e l l d e p t h i s 6,305

f e e t , and t h e w e l l i s p e r f o r a t e d from 6,010 t o 6,040 f e e t .

The

i n j e c t e d u n i t i s t h e Hygiene Sandstone member of t h e P i e r r e Shale. P e r m e a b i l i t y of t h e Hygiene a t t h e s i t e i s v a r i a b l e , g e n e r a l l y ranging from 0.2 t o 14 g p d / f t

2

.

P o r o s i t y v a r i e s from 15 t o 20 p e r c e n t .

I n j e c t i o n of chemical w a s t e s , c o n t a i n i n g p r i n c i p a l l y n i t r o g e n compounds such a s n i t r a t e (No3-), began i n June of 1969.

+

P,

ammonia (NH ) , and u r e a (NH2-C-NH2), 4

A s of October, 1980, roughly 88 m i l l i o n

g a l l o n s of waste s o l u t i o n had been i n j e c t e d through t h e Wycon w e l l . Average i n j e c t i o n r a t e s and p r e s s u r e s v a r y from 100 t o 225 gpm and 650 t o 1,000 p s i , r e s p e c t i v e l y . a l s o vary.

Concentrations of i n j e c t e d s p e c i e s

The range of monthly averages f o r n i t r a t e i s 100 t o 5,000

mg/l; f o r ammonia, 750 t o 6,500 mg/l; f o r u r e a , 120 t o 8,800 rng/l. Dissolved s o l i d s c o n c e n t r a t i o n v a r i e s from 4,000 t o 20,000 mg/l, and t h e i n j e c t e d s o l u t i o n pH ranges from 8.4 t o 10.0.

VI- 1

VII. aquifer:

barrel: brine:

G L O S S A R Y

A porous, permeable, water-saturated geologic u n i t capable of y i e l d i n g economically s i g n i f i c a n t q u a n t i t i e s of water t o wells. Unit of o i l f i e l d measurement e q u a l t o forty-two g a l l o n s . Concentrated b r a c k i s h s a l i n e o r s e a w a t e r s c o n t a i n i n g more than 100,000 mg/l of t o t a l d i s s o l v e d s o l i d s .

cementing:

The o p e r a t i o n whereby a cement s l u r r y i s pumped i n t o a d r i l l h o l e and/or forced behind t h e c a s i n g f o r such purposes a s : s e a l i n g t h e c a s i n g t o t h e w a l l s of t h e h o l e ; preventing unwanted leakage of f l u i d s i n t o t h e h o l e o r m i g r a t i o n of l i q u i d s o r gas i n t o o r o u t of t h e h o l e ; c l o s i n g t h e h o l e back t o a shallower depth; s e a l i n g a dry h o l e ; o r r e d r i l l i n g t o s t r a i g h t e n t h e h o l e ; and plugging and abandonment.

c e n t i p o i s e : A u n i t of v i s c o s i t y based on t h e s t a n d a r d of water a t 20°C, which h a s a v i s c o s i t y of 1.005 c e n t i p o i s e . corrosion:

darcy:

The g r a d u a l d e t e r i o r a t i o n o r d e s t r u c t i o n of a substance o r m a t e r i a l by chemical a c t i o n , f r e q u e n t l y induced by e l e c t r o chemical processes.

A s t a n d a r d u n i t of p e r m e a b i l i t y , e q u i v a l e n t t o t h e passage of one cubic c e n t i m e t e r of f l u i d of one c e n t i p o i s e v i s c o s i t y flowing i n one second under a p r e s s u r e d i f f e r e n t i a l of one atmosphere through a porous medium having a c r o s s - s e c t i o n a l a r e a of one s q u a r e c e n t i m e t e r and a l e n g t h of one c e n t i m e t e r . 1 darcy = 1,000 m i l l i d a r c i e s .

d r i l l stem t e s t : A procedure f o r determining p r o d u c t i v i t y of an o i l o r g a s w e l l by measuring r e s e r v o i r p r e s s u r e s and flow c a p a c i t i e s w h i l e t h e d r i l l p i p e i s i n t h e h o l e and t h e w e l l i s f u l l of d r i l l i n g mud. A d r i l l stem t e s t may be done i n a cased o r uncased h o l e . d u a l i n j e c t i o n : A p r o c e s s of f l u i d i n j e c t i o n which u s e s one w e l l t o i n j e c t f l u i d i n t o two d i f f e r e n t p e r f o r a t e d i n t e r v a l s . Tubing i s run i n s i d e t h e c a s i n g and i s used t o i n j e c t f l u i d t o t h e deeper of t h e two i n t e r v a l s . F l u i d i s i n j e c t e d t o t h e o t h e r i n t e r v a l through t h e annular space between t h e tubing and t h e casing. Packers placed below t h e upper i n t e r v a l and/or above t h e lower i n t e r v a l c o n f i n e i n j e c t i o n t o t h e o b j e c t i v e perforated i n t e r v a l s .

e f f e c t i v e p o r o s i t y : The measure of t h e t o t a l volume of i n t e r c o n n e c t e d void s p a c e of a rock, s o i l o r o t h e r substance. Usually expressed a s a percentage of t h e b u l k volume of m a t e r i a l occupied by t h e i n t e r c o n n e c t e d void space. A heterogeneous mixture of two o r more l i q u i d s n o t normally d i s s o l v e d i n one a n o t h e r , b u t h e l d i n suspension by f o r c e f u l a g i t a t i o n o r by e m u l s i f i e r s which modify t h e s u r f a c e t e n s i o n of t h e d r o p l e t s t o prevent coalescence.

emulsion:

f a c i e s change: A l a t e r a l o r v e r t i c a l v a r i a t i o n i n t h e l i t h o l o g i c c h a r a c t e r i s t i c s of contemporaneous sedimentary d e p o s i t s . It i s caused by, o r r e f l e c t s , a change i n t h e d e p o s i t i o n a l environment. fault:

A s u r f a c e o r zone of f r a c t u r e d rock along which t h e r e h a s been displacement.

f l o c c u l a t i o n : The agglomeration of c o l l o i d a l and f i n e l y d i v i d e d suspended m a t t e r . formation:

A body of r o c k c h a r a c t e r i z e d by a degree of l i t h o l o g i c homogeneity, mappable on t h e e a r t h ' s s u r f a c e o r t r a c e a b l e i n t h e subsurface.

geophysical l o g s : The r e c o r d s of a v a r i e t y of logging t o o l s which measure t h e geophysical p r o p e r t i e s of g e o l o g i c formations p e n e t r a t e d and t h e i r contained f l u i d s . These p r o p e r t i e s i n c l u d e e l e c t r i c a l c o n d u c t i v i t y and r e s i s t i v i t y , t h e a b i l i t y t o t r a n s m i t and r e f l e c t s o n i c energy, n a t u r a l r a d i o a c t i v i t y , hydrogen i o n c o n t e n t , temperature, g r a v i t y , e t c . These geophysical p r o p e r t i e s a r e then i n t e r p r e t e d i n terms of l i t h o l o g y , p o r o s i t y , f l u i d c o n t e n t and chemistry. i n j e c t i o n p r e s s u r e : The p r e s s u r e per u n i t a r e a a c t i n g on t h e i n j e c t e d f l u i d w i t h i n t h e w e l l . Usually measured a t t h e wellhead i n pounds per s q u a r e inch. i n j e c t i o n w e l l : A w e l l i n t o which f l u i d ( s ) i s pumped f o r t h e purpose of i n c r e a s i n g t h e y i e l d of o i l and/or gas from producing w e l l s i n t h e a r e a o r t o d i s p o s e of f l u i d s i n t h e s u b s u r f a c e environment by allowing them t o e n t e r by g r a v i t y flow o r i n j e c t i o n under pressure. packer:

pay zone:

I n w e l l d r i l l i n g , a d e v i c e lowered i n t h e l i n i n g t u b e s which s w e l l s a u t o m a t i c a l l y o r can b e expanded by manipulation from t h e s u r f a c e t o produce a w a t e r - t i g h t s e a l a g a i n s t t h e s i d e s of t h e b o r e h o l e o r t h e c a s i n g , t h u s e n t i r e l y excluding water from d i f f e r e n t h o r i z o n s . The term a p p l i e d t o t h a t p o r t i o n of t h e o i l r e s e r v o i r which exceeds a minimum p o r o s i t y determined by t h e o p e r a t i n g company of t h e f i e l d ( u s u a l l y 10%) and l i e s above t h e o i l water c o n t a c t .

p e r m e a b i l i t y : The measure of t h e r e l a t i v e e a s e of f l u i d flow under unequal p r e s s u r e . The customary u n i t of measurement i s t h e millidarcy. porosity:

The measure of t h e volume of p o r e s p a c e w i t h i n a r o c k d i v i d e d by t h e b u l k volume of t h e r o c k . U s u a l l y expressed as a p e r c e n t a g e .

reservoir:

The t e r m a p p l i e d t o t h a t p o r t i o n of a g e o l o g i c f o r m a t i o n which c o n t a i n s hydrocarbons i n a s i n g l e h y d r a u l i c a l l y connected system.

unit:

The term a p p l i e d t o t h e s u r f a c e a r e a covered by a f o r m a l agreement between o p e r a t o r s and r o y a l t y owners approved by t h e U.S. G e o l o g i c a l Survey a n d / o r t h e Wyoming O i l and Gas Conservation Commission. The purpose of t h e agreement i s t o i n c r e a s e t h e e f f i c i e n c y of hydrocarbon withdrawal by c o n s o l i d a t i n g f i e l d a c t i v i t i e s under one o p e r a t o r .

VIII.

L O C A T I O N

A N D

N U M B E R I--N G

SYSTEM

The l o c a t i o n s of w e l l s , u n i t s , and f i e l d s given i n t h i s r e p o r t a r e d e s i g n a t e d by a w e l l numbering system based on t h e f e d e r a l system of l a n d s u b d i v i s i o n .

The f i r s t number d e n o t e s t h e township, t h e

second number d e n o t e s t h e range, and t h e t h i r d number denotes t h e section.

Any l e t t e r s f o l l o w i n g t h e s e c t i o n number denote t h e l o c a t i o n

within the section.

The s e c t i o n i s d i v i d e d i n t o q u a r t e r s (160 a c r e s

each) and l e t t e r e d a, b , c , and d i n a counter-clockwise d i r e c t i o n , beginning i n t h e n o r t h e a s t q u a r t e r .

S i m i l a r l y , each q u a r t e r may be

f u r t h e r d i v i d e d i n t o q u a r t e r s (40 a c r e s ) and d i v i d e d a g a i n i n t o 10a c r e t r a c t s and l e t t e r e d a s b e f o r e .

The f i r s t l e t t e r , i f shown, following t h e s e c t i o n number denotes t h e q u a r t e r s e c t i o n ; t h e second l e t t e r , i f shown, denotes t h e q u a r t e r q u a r t e r s e c t i o n ; t h e t h i r d l e t t e r , i f shown, denotes t h e q u a r t e r - q u a r t e r quarter s e c t i o n , o r lo-acre t r a c t . above, w e l l number 49N-69W-21 of S e c t i o n 21, T. 49 N.,

For example, i n t h e i l l u s t r a t i o n

cab i s i n t h e N W ~of t h e NEk of t h e S W ~

R. 69 W.

1x0

R E F E R E N C E S

Barlow, A. C . , 1972, Basic d i s p o s a l - w e l l d e s i g n , i n Symposium on underground waste management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 1 8 , T u l s a , Oklahoma, pp. 72-76. Barnes, Ivan, 1972, Water-mineral r e a c t i o n s r e l a t e d t o p o t e n t i a l f l u i d i n j e c t i o n problems, i n Symposium on underground waste management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 18, T u l s a , Oklahoma, pp. 294-296. B a r t k e , T. C . , Dockter, L., S t e r n e r , T. E . , Virgona, T. E . , and Wodsac, L. F., 1980, S t a t u s r e p o r t on t h e Hanna 111 and Hanna I V underground c o a l g a s i f i c a t i o n experiments, i n Proceedings of t h e 4 t h Underground Coal Conversion Symposium: 9 p. Bay, C. A . , 1962, S i g n i f i c a n t u n c e r t a i n t i e s i n c u r r e n t s a l t s o l u t i o n e x t r a c t i o n o p e r a t i o n s , i n Symposium on s a l t : A. C. B e r s t i c k e r , Ed., Northern Ohio Geological A s s o c i a t i o n , pp. 467-481. Biggs, P a u l , and Koch, C h a r l e s A . , 1970, Waterflooding of o i l f i e l d s i n Wyoming t o 1968: U.S. Bureau of Mines, 147 p. Biggs, P a u l , and Espach, Ralph H., 1960, Petroleum and n a t u r a l g a s f i e l d s i n Wyoming: Bureau of Mines B u l l e t i n 582, 538 p. Bradley, W. H., and H. P. E u g s t e r , 1969, Geochemistry and paleolimnology of t h e t r o n a d e p o s i t s and a s s o c i a t e d authenogenic m i n e r a l s of t h e Green River Formation of Wyoming: U.S. Geological Survey Profess i o n a l Paper 496-By 71 p. Campbell, G. G . , Brandenburg, C. F., and Boyd, R. M., 1974, Preliminary e v a l u a t i o n of underground c o a l g a s i f i c a t i o n a t Hanna, Wyoming: U.S. Bureau of Mines, TPR 82. C l a r k , N. J . , 1969, Elements of petroleum r e s e r v o i r s : i n Henry L. Koherty, S e r i e s of Soc. of P e t r o . Engineers t r a n s a c t i o n s , p. 78. C r a f t , B. C . , and Hawkins, M. F . , engineering: Prentice-Hall, 437 pa

1959, Applied petroleum r e s e r v o i r I n c . , Englewood C l i f f s , New J e r s e y ,

Donaldson, E r l e C., 1972, I n j e c t i o n Symposium on underground waste i m p l i c a t i o n s : T. D. Cook, Ed., G e o l o g i s t s : Memoir 18, T u l s a ,

IX- 1

w e l l s and o p e r a t i o n s today, i n management and environmental American Assoc. of Petroleum Oklahoma, pp. 24-46.

Evers, John, 1981, A s s o c i a t e P r o f e s s o r of Petroleum Engineering, U n i v e r s i t y of Wyoming, p e r s o n a l communication. Fahey, J. J . , 1962, S a l i n e m i n e r a l s of t h e Green River Formation: U.S. Geological Survey P r o f e s s i o n a l Paper 405, 50 p. F i s h e r , W. T., and Aiman, W. R . , 1978, LLL i n s i t u c o a l g a s i f i c a t i o n program, Q u a r t e r l y p r o g r e s s r e p o r t , January t o March, 1978: Lawrence Livermore Laboratory, UCRL-50026-78-1, 44 p. G a l l e y , John E., 1968, Geologic framework f o r s u c c e s s f u l underground waste management, i n Symposium on underground waste management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 18, T u l s a , Oklahoma, pp. 119-125. Galley, John E . , ed., 1968a, Subsurface d i s p o s a l i n g e o l o g i c b a s i n s A s t u d y of r e s e r v o i r s t r a t a , A.A.P.G. Memoir 1 0 , American Assoc. of Petroleum G e o l o g i s t s , I n c . , Tulsa, Oklahoma. Galloway, W. E . , Henry, C. D . , and Smith, G. E,, 1980, P r e d i c t i n g response of an a q u i f e r system t o uranium e x t r a c t i o n : O a k v i l l e A q u i f e r , Texas C o a s t a l P l a i n : U n i v e r s i t y of Texas, A u s t i n , 414 p. Gregg, D. W., H i l l , R. W . , and Olness, D. U . , 1976, An overview of t h e S o v i e t e f f o r t i n underground g a s i f i c a t i o n of c o a l : Lawrence Livermore Laboratory, UCRL-52004. Gulens, J . , Champ, D. R . , and Jackson, R. E . , 1979, I n f l u e n c e of redox environments on the m o b i l i t y of a r s e n i c i n ground w a t e r , i n E. A. Jenne, Ed., Chemical modeling of aqueous systems: American Chemical S o c i e t y Symposium S e r i e s 93, pp. 81-98. Gulf Research and Development Corporation, 1980, Underground g a s i f i c a t i o n f o r s t e e p l y d i p p i n g beds: Gulf Research and Development Corp., P i t t s b u r g h , Pa., SAN-13108-35, 29 p. Hallden, 0 . S , , 1961, Underground n a t u r a l gas s t o r a g e (Herscher Dome) i n ground w a t e r contamination: U.S. Dept. of HEW, Technical Report W61-5, C i n c i n n a t i , Ohio, pp. 110-115. Hanshaw, Bruce B . , 1972, N a t u r a l membrane phenomena and s u b s u r f a c e waste emplacement, i n Symposium on underground waste management and environmental i m p l i c a t i o n s : T. D. Cook, E d , , American Assoc. of Petroleum G e o l o g i s t s : Memoir 18, T u l s a , Oklahoma, p. 308. Henderson, J . K . , 1962, Well c o n s t r u c t i o n ; p o s s i b l e c a u s e s of f a i l u r e and remedial measures, i n Symposium on s a l t : A. C . B e r s t i c k e r , Ed., Northern Ohio Geological S o c i e t y , pp. 555-562.

Hingston, F. J . , s e l e n i t e by Advances i n Washington,

P o s n e r , A. M . , and Quirck, J. P., 1968, Adsorption of g e o t h i t e , i n a d s o r p t i o n from aqueous s o l u t i o n : Chemistry S e r i e s 79, American Chemical S o c i e t y , D. C . , pp. 82-90.

Howard, G. C . , and F a s t , C. R., 1970, Hydraulic f r a c t u r i n g monograph Volume 2, Henry L. Doherty S e r i e s , S o c i e t y of Petroleum Engineers, 203 p. Howard, J. H . , 111, 1972, C o n t r o l of geochemical behavior of selenium i n n a t u r a l w a t e r s by a d s o r p t i o n on hydrous f e r r i c o x i d e s , i n D. D. Hemphill, Ed., T r a c e s u b s t a n c e s i n environmental h e a l t h : U n i v e r s i t y of M i s s o u r i , Columbia, v o l . 5 , pp. 485-495. Howard, J. H., 111, 1977, Formation of f e r r o s e l i t e and selenium behavior i n t h e v i c i n i t y of o x i d i z i n g s u l f i d e and uranium d e p o s i t s : Geochemica e t Cosmochimica Acta, v o l . 41, pp. 1665-1678. Hower, W. F . , L a s a t e r , R. M . , and Mihram, R. G . , 1972, C o m p a t i b i l i t y of i n j e c t i o n f l u i d s w i t h r e s e r v o i r components, i n Symposium on underground w a s t e management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 1 8 , T u l s a , Oklahoma, pp. 287-292. Hubbert, M. K., 1953, Entrapment of petroleum under hydrodynamic c o n d i t i o n s : AAPG B u l l e t i n , v o l . 37, pp. 1954-2026. Hubbert, M. K O y and W i l l i s , David G . , 1972, Mechanics of h y d r a u l i c f r a c t u r i n g , i n Symposium on underground w a s t e management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 1 8 , T u l s a , Oklahoma, pp. 239-257. Hughes, R. V . , and P f i s t e r , R. J . , 1947, Advantages of b r i n e s i n secondary r e c o v e r y of petroleum by w a t e r f l o o d i n g , i n American I n s t i t u t e of Mining M e t a l l u r g i c a l Engineers T r a n s c r i p t s , Petroleum D i v i s i o n : v o l . 170, pp. 187-201. I n t e r s t a t e O i l Compact Commission, 1960, P r o d u c t i o n and d i s p o s a l of o i l f i e l d b r i n e s i n t h e U.S. and Canada: Oklahoma C i t y , Oklahoma, 95 p. I n t e r s t a t e O i l Compact Commission, 1974, Secondary and t e r t i a r y o i l r e c o v e r y p r o c e s s e s : Oklahoma C i t y , Oklahoma, 187 p. Kaback, D. S., 1977, The geochemistry of molybdenum i n stream w a t e r s and s e d i m e n t s , C e n t r a l Colorado: U n i v e r s i t y of Colorado, Ph.D. d i s s e r t a t i o n , 224 p. Langmuir, D . , 1978, Uranium s o l u t i o n - m i n e r a l e q u i l i b r i a a t low temperat u r e s w i t h a p p l i c a t i o n s t o sedimentary o r e d e p o s i t s : Geochimica e t Cosmochimica Acta, v. 42, pp. 547-569. Leach, R. O . , and Wagner, 0. R., 1966, E f f e c t of i n t e r f a c i a l t e n s i o n on displacement e f f i c i e n c y : Trans. AIME, 237, 11, pp. 335-339.

Mair, J. D . , 1962, The Canadian Brine Limited Brine F i e l d a t Windsor, O n t a r i o , i n Symposium on s a l t : A. C . B e r s t i c k e r , Ed., Northern Ohio Geological A s s o c i a t i o n , pp. 495-505. McKelvey, V. E . , E v e r h a r t , D. L., and G a r r e l s , R. M., 1955, O r i g i n of uranium d e p o s i t s : Economic Geology, 50th Anniversary Volume, pp. 464-533. Mead, S. W., Campbell, J. H., Ganow, H. C . , Langland, R. T . , Greenlaw, R. C . , Wang, F. T . , and Homsy, R. V . , 1978, LLL environmental s t u d i e s of i n s i t u c o a l g a s i f i c a t i o n : Annual r e p o r t f o r f i s c a l y e a r 1977, Lawrence Livermore Laboratory, UCRL-50032-78, 6 3 p. Oak Ridge N a t i o n a l Laboratory, 1977, Environmental h e a l t h and c o n t r o l a s p e c t s of c o a l conversion: An i n f o r m a t i v e overview: Oak Ridge N a t i o n a l Laboratory, 474 p. Sharpley, J. F., 1961, M i c r o b i o l o g i c a l c o r r o s i o n i n w a t e r f l o o d s , i n Corrosion: v o l . 17. S l o a t , B . , 1971, Choosing t h e r i g h t f l o o d s f o r polymer t r e a t m e n t : Petroleum Engineer, March, 1971, pp. 84-95. Smigh, C . R . , 1966, Mechanics of secondary o i l recovery: P u b l i s h i n g Co., New York, New York, 282 p. S t a n t o n , R. L., 1972, Ore Petrology: New York, 713 p.

Reinhold

McGraw-Hill Book Company, New York,

Walsh, M. P., S c h e c h t e r , R. S., Humenick, M. J . , and o t h e r s , 1979, A model f o r p r e d i c t i n g t h e r e s t o r a t i o n o f , and ammonium m i g r a t i o n from, i n s i t u mines of South Texas: Seminar, American I n s t i t u t e of Mining, M e t a l l u r g i c a l and Petroleum Engineers, I n c . , pp. 29-38. Wang, F. T., 1979, The s o r p t i v e p r o p e r t i e s of c o a l , i n Proceedings of t h e F i f t h Underground Coal Conversion Symposium: U.S. Department of Energy Conference 790630, pp. 403-408. Warner, Don L., and Lehr, Jay H . , 1977, An i n t r o d u c t i o n t o t h e technology of s u b s u r f a c e wastewater i n j e c t i o n : Environmental P r o t e c t i o n Agency O f f i c e of Research and Development, Ada, Oklahoma, 345 p. Warner, Don L., K o e d e r i t z , Leanard F., Simon, Andrew D . , and Yow, M. Gene, 1979, Radius of p r e s s u r e i n f l u e n c e of i n j e c t i o n w e l l s : Environmental P r o t e c t i o n Agency O f f i c e of Research and Development, Ada, Oklahoma, 204 p. Witherspoon, P. A., and Neuman, S. P., 1972, Hydrodynamics of f l u i d i n j e c t i o n , i n Symposium on underground waste management and environmental i m p l i c a t i o n s : T. D. Cook, Ed., American Assoc. of Petroleum G e o l o g i s t s : Memoir 18, Tulsa, Oklahoma, pp. 258-272.

Wyoming Department of Environmental Quality Information F i l e s , 1981.

-

Land Quality Division:

Wyoming O i l and Gas Conservation Commission, 1978, Wyoming o i l and gas s t a t i s t i c s : Casper , Wyoming, 127 p . Wyoming O i l and Gas Conservation Commission, 1979, Wyoming o i l and gas s t a t i s t i c s : Casper, Wyoming, 118 p. Wyoming O i l and Gas Conservation Commission, 1980, Information F i l e s . Zaba, Joseph, and Doherty, W. T., 1970, P r a c t i c a l petroleum e n g i n e e r ' s handbook; 5 t h E d i t i o n : Gulf Publishing Company, Houston, Texas.