(southeastern Saskatchewan and southwestern Manitoba) ... and compositionally distinctive source rocks in southeastern Saskatchewan and southwest-.
BULLETIN OF CANADIAN PETROLEUM GEOLOGY VOL. 40, NO. 3 (SEPT., 1992) P. 254-273
Oil families and their sources in Canadian Williston Basin, (southeastern Saskatchewan and southwestern Manitoba) KIRK G. OSADETZ, PAUL W. BROOKS AND LLOYD R. SNOWDON Institute of Sedimentary and Petroleum Geology 3303 - 33rd Street N.W. Calgary, Alberta T2L 2A7
ABSTRACT
Four petrographically and compositionally distinctive source rocks in southeastern Saskatchewan and southwestern Manitoba produce oils with restricted stratigraphic occurrence, which includes their sources. Kukersites, marine Type I source rocks in Middle and Upper Ordovician formations, are the source of oils (Family A) which occur in Ordovician to Middle Devonian strata and are characterized by diagnostic saturate fraction gas chromatograms (SFGC) accompanied by low C23 tricyclic/C30 pentacyclic terpane (C23/C30) ratios and a C34 hopane prominence. Middle Devonian Winnipegosis Formation marine source rocks vary compositionally and petrographically from platform depositional settings to starved basinal settings. These different source rocks produce oils (Family D) occurring in Silurian to Mississippian strata. Their terpane compositional characteristics are like kukersite derived oils, but they are distinguished by a greater relative acyclic isoprenoid and higher carbon number n-alkane abundance. These oils are subdivided, using nC~v/pristane and nC~8/phytane ratios, into those from platformal (D 0 and starved basinal (D2) sources. Oils in Upper Devonian, Mississippian and Mesozoic strata are divided into two groups with different sources. Predominantly Type II marine organic matter in the Upper Devonian-Mississippian Bakken Formation shale members is the source for oils (Family B) in the Middle member, and is characterized by the highest pristane/phytane (Pr/Ph) and C23/C30 ratios accompanying n-alkane and hopane profiles lacking predominance and prominence, respectively. Type II marine sources in the Mississippian Lodgepole Formation are the source of most oils (Family C) in Mississippian Madison Group and Mesozoic strata. These oils have high C23/C30 ratios, but are distinguished from Bakken-se,urced oils by consistently lower Pr/Ph ratios, even/odd n-alkane predominance and C35 hopane prominence. RI~SUMI~
Quatre roches mbres p6trographiquement et compositionellement distinctes du sud-est du Saskatchewan et du sudouest du Manitoba produisent des huiles dont l'occurrence stratigraphique est restreinte et inclu leurs sources. Des kukersites, roches mbres marines de Type I dans les formations de l'Ordovicien moyen et sup6rieur, sont la source des huiles (Famille A) qui se trouvent dans les strates de l'Ordovicien et du D6vonien moyen et sont caract6ris6es par des chromatogrammes en phase gazeuse de la fraction satur6e (SFGC) diagnostiques accompagn6s de faibles rapports de terpanes C23 tricyclique/C30 pentacyclique (C23/C30) et d'une pro6minence en hOpane C34. Les roches mbres marines de la formation Winnipegosis du D6vonien moyen varient compositionellement et p6trographiquement depuis les milieux de s6dimentation de plate-forme vers ceux de bassin h faible remplissage s6dimentaire. Ces roches mbres diff6rentes produisent des huiles (Famille D) qui se trouvent dans des strates siluriennes ?a mississippiennes. Leurs caract6ristiques de composition en terpane sont semblables a celles des huiles d6riv6es a partir de kukersite, mais elles sont distingu6es par des abondances relativement sup6rieures en isoprEno'ides acycliques et en n-alcanes h nombre de carbone 61ev6. Ces huiles sont subdivis6es, sur base des rapports nCt7/pristane et nC~8/phytane, comme provenant de sources de plateforme (D1) ou de bassin ~ faible remplissage s6dimentaire (D2). Les huiles dans les couches du D6vonien sup6rieur, Mississippien et M6sozo'fque sont divis6es en deux groupes ayant des sources diff6rentes. La matibre organique principalement marine de Type II dans les membres argileux de la formation Bakken d'~ge D6vonien-Mississippien est la source des huiles (Famille B) dans le membre Middle, et est caract6ris6e par les rapports pristane/phytane (Pr/Ph) et C23/C30 les plus hauts accompagnant des profils n-alcane et hopane manquant de predominance et de pro6minence, respectivernent. Les sources marines de Type II dans la formation Lodgepole du Mississippien sont les sources de la plupart des huiles (Famille C) dans les strates mississippiennes du groupe Madison et dans les strates mEsozo'/ques. Ces huiles ont des rapports C23/C30 61ev6s, mais sont distinctes des huiles issues de Bakken par leurs rapports Pr/Ph uniform6rnent inf6rieurs, la pr6dominance des rapports de n-alcanes pairs/impairs et la pro6minence d'hopane C35. Traduit par Patrice de Caritat
*Geological Survey of Canada Contribution Number 48691 254
255
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
INTRODUCTION
terize recent exploration and indicate a renewed interest in deeper plays.
SETTING
The Williston Basin Madison Group (Mississippian) subcrop petroleum province (Kent, 1987; McCabe, 1963; Edie, 1958) comprises roughly 12% of the initial light and medium petroleum reserve in the Western Canada Sedimentary Basin ( - 2 8 1 x 106 m3 or 1.8 Bbbls.; Saskatchewan Energy and Mines, 1988; Manitoba Energy and Mines, 1986) (Figs. 1, 2). N o t a b l e sub-Madison petroleum provinces occur on the N e s s o n and Cedar Creek anticlines of the United States (Lefever et al., 1987; Clement, 1987). Older strata, so productive in the United States, remain little explored in Canada. Recent discoveries in Ordovician structural (Potter and St. Onge, 1991; Osadetz and Haidl, 1989) and Middle Devonian reef p l a y s (Martindale et a l . , 1991; M a r t i n d a l e and MacDonald, 1989), and innovative exploration techniques, particularly horizontal drilling in American Bakken source rocks (Lefever et al., 1991; Fischer and Rygh, 1989), charac-
PREVIOUS STUDIES
Williams (1974) identified three oil families (Table 1) and used solvent extracts from formations near their most frequent stratigraphic occurrence in an oil-source correlation (Williams, 1974; Dow, 1974). Type I oils, predominantly in Ordovician and Silurian reservoirs, had distinctive gasoline fraction gas chromatograms (GFGC's) and C~5+ saturate fraction gas chrom a t o g r a m s ( S F G C ' s ) and were associated with M i d d l e O r d o v i c i a n W i n n i p e g shales. Most p o o l s , from U p p e r Devonian, Mississippian and Mesozoic reservoirs, contain Type II oils inferred to have an uppermost D e v o n i a n Mississippian Bakken source, while another family, Type III, restricted to Pennsylvanian reservoirs, were attributed to Tyler Formation sources. Carbon and sulphur isotope ratios follow z~ ~ =%%= BELLEFOURCHE
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i
LEGEND I
~ OIL FIELD pROVINCE
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=
210°C fraction % hydrocarbons; S/A > 210°C fraction saturate hydrocarbon/aromatic hydrocarbon ratio; Pr/Ph pristane/phytane ratio Columns keyed to steranes identified in Figure 7: D/R = peaks 6/14; S/R Ster = 20/23; 1~I3/R= 21/23; 27 = (14/(14+19+23)) x 100; 28 = (19/(14+19+23)) x 100; 29 = peaks (23/(14+19+23)) × 100. Columns keyed to terpanes identified in Figure 6:23/30 = peaks aft; 27/30 = peaks d/f; 28/30 = peaks r/f; 29/30 = peaks e/f; Ts/Tm = peaks c/d; S/R Terp = peaks j/k; H/M = f/g; HP = carbon number prominence among extended hopanes, peaks h-q. n = no prominence, 34 = C34 hopanes, 35 = C35 hopanes.
259
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
i
SASKATCHEWAN
MANITOBA
L-k 1279 5151
I •523
• 512
I I
•596 • 511
•585
L
11466 [. 0595 I
•725 •722 •721
0533 514 •
• 560 • 495 I •494 L 500Ore •920 539 • • 5 1 6 I 127311"--13121274 801 • ~ 2 7 5 1 / 276•.,~499 • 8,~o w i n• _8 0_2 ~ 1 3 1 3 7 5 5 1 ~ 1 9 2 4 ~ ' ~ " ~ _ 1 2 9 0 II 841 0520 " ' d 2 8 8 2 9 1 --842 m5471 1289 552 • 497 • • 5 5 5
' 651
3t1"554
C A N A D A
546 --6979 • A1165
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-559 ~ 5 6 8 550 //!
U.S.A.
577
714
•
LEGEND
I
• FAMILY A
i i i
"~ FAMILY B • FAMILY C • FAMILY D
I
i Fig. 4. Oil pool sample geographic distribution in southeastern Saskatchewan and southwestern Manitoba. Sample numbers "and oil families refer to oil pools listed in Table 5.
CRITICAL COMPOSITIONAL AND PETROGRAPHIC CHARACTERISTICS
Upper Ordovician Bighorn Group kukersites occur in Yeoman, Herald and Stony Mountain formations (Fig. 2), but the richest accumulations occur in the Yeoman Formation (Table 2, Fig. 3) (Osadetz and Snowdon, in review; Osadetz et al., 1989; Kohm and Louden, 1982, 1978; Kendall, 1976). Bighorn, Type I kukersites, can be distinguished from poorer Winnipeg shale Type II source rocks (Table 2, Fig. 2) (Osadetz et al., 1989; Dow, 1974) by both composition and petrography. Kukersites, kerogenous carbonate mudstones with Gloeocapsomorpha prisca alginite, in layered and disseminated microfacies (Stasiuk et al., 1991; Stasiuk and Osadetz, 1990), have solvent extract SFGC's with very low relative Pr and Ph abundances and a marked odd n-alkane predominance in the range nC15-nC20 (Fig. 5). Bituminous Winnipeg shale lithologies resemble kukersite disseminated microfacies, but with acritarch, chitinozoa, and chitinous skeletal fragments mixed with less abundant, disseminated cup-like agglomerations of G. prisca alginite (Osadetz et al., 1989). Winnipeg solvent extract SFGC's have relatively more abundant pristane and phytane, Pr/Ph > 1, an n-alkane profile low in homologues
> nC22 and lacking any predominance. Terpanes from Bighorn and Winnipeg sources (Fig. 6) are characterized by C23 tricyclic/C30 pentacyclic terpane (C23/C30) ratio < 0.5, and sometimes show a C34 hopane prominence, particularly at higher maturities (Table 4). Steroidal alkanes (Fig. 6) have a low relative abundance and low C28/(C27+C285C29) sterane ratio (Table 4), but Ordovician source rocks have high DIA/REG, even at low maturities. Additional compositional characteristics of Bighorn kukersites are discussed by Fowler (1992). Different stratigraphic settings and petrographic characteristics in Winnipegosis sources are matched by variable solvent extract compositions. Platformal organic microfacies are dominated by Nostocaceae genus-type cyanobacterial lamatginite and rare Leiosphaeridia and Tasmanites unicellular alginite having features and textures strikingly similar to G. prisca layered microfacies (Stasiuk et al., 1991). In platform marginal depositional settings, organic rich microlaminae of bituminite with variable amounts of liptodetrinite and minor Leiosphaeridia and Tasmanites unicellular alginite with traces of spiny sphaeromorph acritarchs occur (Stasiuk et al., 1991). In basinal depositional settings, organic macerals are dominated by Leiosphaeridia and Tasmanites unicellular alginite in a granular bituminite groundmass (Stasiuk et al., 1991).
K.G OSADETZ, P.W. BROOKS and L.R. SNOWDON
260
Table 5. Oil pool sample location descriptions #
Pool Name
Depth (m)
Location
Family A - Bighorn Group Source 549 OUNGRE WEST 2932.5 04-22-003-15W2 550 LAKE ALMA 3061.5 07-23-001-17W2 902 WEIR HILL 2470.0 09-29-006-06W2 1165 MINTON 2608.9 1 1 - 0 2 - 0 0 3 - 2 1W2 6979 MINTON 2863.8 1 1 - 0 2 - 0 0 3 - 2 1W2 7595 BEAUBIER 3056.9 03-20-002-16W2 Family B - Bakken Formation Source 515 ROCANVILLE 654.3 02-11-016-31Wl 554 RONCOTT 1824.0 09-34-005-25W2 1279 DALY 879.5 13-21-010-29Wl Family C - Lodgepole Formation Source 494 INNES WEST 1335.4 13-31-007-11W2 495 SOUTH PARKMAN 1090.8 16-09-008-33Wl 497 VIEWFIELD 1349.8 13-33-007-08W2 499 STEELMAN 1394.1 13-27-004-05W2 500 BENSON 1335.3 05-25-006-08W2 511 KENOSEE 1196.5 12-26-010-03W2 512 RED JACKET 664.5 10-04-014-32Wl 514 RALPH 1308.5 01-32-007-13W2 516 NOTTINGHAM 1134.6 04-14-005-33Wl 520 WORKMAN 1212.5 03-03-002-32Wl 523 WAPELLA 670.2 13-34-014-01 W2 533 STAR VALLEY 1161.5 13-11-009-06W2 539 ALIDA WEST 1235.1 06-06-006-33Wl 540 OUNGRE 1823.3 03-29-002-14W2 546 FREDA LAKE 1703.3 16-30-004-18W2 547 ELMORE 1180.3 09-04-001-31Wl 548 GAINSBOROUGH 1064.0 07-28-002-30Wl 553 HUMMINGBIRD 2226.0 05-26-002-19W2 555 CLAIRLAW 1231.5 05-29-007-05W2 556 HUMMINGBIRD 1890.0 11-26-002-19W2 557 NEPTUNE 1752.0 04-06-004-16W2 559 LAKE ALMA 1984.0 04-29-001-17W2 560 FREEMANTLE 1189.7 11-16-008-03W2 565 STORTHOAKS 1041.5 A09-17-005-31Wl 585 HANDSWORTH 1178.4 A09-36-010-08W2 595 PARKMAN 1082.5 08-11-010-01W2 596 MOOSE VALLEY 1183.5 12-14-012-06W2 711 WASKADA 921.0 16-13-001-26Wl 714 WASKADA 928.0 05-03-002-26Wl 717 WASKADA 925.5 04-25-001-26W1 721 DALY 725.7 10-13-010-28Wl 722 VIRDEN 620.3 09-26-010-26Wl 725 VIRDEN 607.5 04-27-011-26Wl Family D1 - Winnipegosis Formation Platform - Platform Margin Source 466 WAPOLE 1080.3 05-33-010-32Wl 551 HUMMINGBIRD 2313.5 10-26-002-19W2 552 KISBEY 1620.5 07-27-007-06W2 558 HOFFER 1940.0 05-30-001-15W2 568 HOFFER 1944.5 09-27-001-15W2 577 FLAT LAKE 1975.0 06-05-001-16W2 Family D2 - Winnipegosis Formation Basin Source 755 TABLELAND 2601.0 04-36-002-10W2 756 TABLELAND 2581.0 08-22-002-09W2 8OO TABLELAND 2562.0 15-02-003-10W2 801 MACOUN 2468.0 16-11-004-10W2 802 BIENFAIT 2436.0 12-31-003-06W2 841 OXBOW 2327.0 10-24-002-03W2 842 OXBOW 2310.0 10-24-002-03W2 924 TABLELAND 2607.0 11-30-002-09W2 1273 BENSON 2282.0 16-05-006-08W2 1274 STEELMAN 2326.0 05-05-005-06W2 1275 MACOUN 2380.0 16-30-004-08W2 1276 MACOUN 2395.0 06-30-004-08W2 1288 HITCHCOCK 2520.0 07-19-003-08W2 1289 HITCHCOCK 2500.0 15-19-003-08W2 1290 HITCHCOCK 2490.0 14-25-003-09W2 1291 HITCHCOCK 2465.0 09-25-003-09W2 1312 BENSON 2259.3 09-09-006-08W2 1313 STEELMAN 2410.0 15-18-004-06W2
Zone Herald-Yeoman Herald Yeoman Winnipegosis Red River Herald Bakken Bakken Bakken A Frobisher Tilston/Souris Valley Frobisher Midale Midale Tilston Jurassic Midale Alida Frobisher Wapella Frobisher/Alida Alida Ratcliffe Ratcliffe Midale Frobisher/Alida Bakken Frobisher/Alida Ratcliffe Ratcliffe Ratcliffe Watrous Alida Tilston Alida Souris Valley Tilston Mission Canyon Mission Canyon Lower Amaranth Lodgepole A Lodgepole B Lodgepole A Birdbear Birdbear Birdbear Ratcliffe Ratcliffe Ratcliffe Winnipegos~s WinnipegosJs Winnipegos~s Winnipegosls Winnipegosis WinnlpegosJs Winnipegosls Winnipegos~s Winnipegos~s Winnipegosls Winnipegos~s Winnipegosls Winnipegosls Winnipegos~s Winnipegosls Winnipegosls Winnipegos~s Winnipegos~s
261
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
Table 6. Select oil pool compositional characteristics #
Depth(m)
FAMILY A 549 2932.5 550 3061.5 920 2470.0 1165 2608.9 6979 2863.8 7597 3056.9 FAMILY B 515 654.3 554 1824.0 1279 879.5 FAMILY C 494 1335.4 495 1090.8 497 1349.8 499 1349.1 500 1335.3 511 1196.5 512 664.5 514 1308.5 516 1134.6 520 1212.5 523 670.2 533 1161.5 539 1235.1 540 1823.3 546 1703.3 547 1180.3 548 1064.0 553 2226.0 555 1231.5 556 1890.0 557 1752.0 559 1984.0 560 1189.7 565 1041.5 585 1178.4 595 1082.5 596 1183.5 711 921.0 714 928.0 717 925.5 721 725.7 722 620.3 725 607.5 FAMILY D 466 1080.3 551 2313.5 552 1620.5 558 1940.0 568 1944.5 577 1975.0 755 2601.0 756 2581.0 800 2562.0 801 2468.0 802 2436.0 841 2327.0 842 2310.0 924 2607.0 1273 2282.0 1274 2326.0 1275 2380.0 1276 2395.0 1288 2520.0 1289 2500.0 1290 2490.0 1291 2465.0 1312 2259.3 1313 2410.0
PI 1
HV
Q
R
S
T
U
V
W
API
%HC
S/A
Pr/Ph 17/Pr
0.96 59.7 4.26 1.14 59.3 4.75 0.68 34.0 1.81 0.70 58.4 6.40 Sample extracted from Sample extracted from
3.49 1.58 5.33 3.88 3.21 4.73 67.04 14.08 1.32 3.13 36.08 6.13 3.12 2.00 15.95 2.26 core no gasoline range data core no gasoline range data
0.17 0.18 0.37 0.39
0.08 0.06 0.17 0.10
28.4 33.3 24.0 33.0 33.3 ND
63.7 77.0 61.7 87.8 70.8 46.1
0.64 0.82 0.66 1.77 1.60 1.17
1.45 1.68 1.11 0.98 1.29 1.10
29.5 22.0 8.95 13.77 10.78 10.66
0.52 0.45 0.71
22.3 24.2 20.1
1.95 1.21 1.39
1.47 54.00 0.64 13.0 1.49 9.44 10.99 4.64 1.30 446.2 178.2 210.3
0.80 0.51 0.48
0.47 0.39 0.43
36.5 40.5 40.0
90.6 93.0 91.3
1.16 1.47 1.48
1.52 1.76 1.40
0.55 1.19 0.84 1.07 1.85 0.76 0.09 0.49 1.12 1.39 0.22 0.56 0.80 0.63 0.60 1.42 1.61 0.63 0.60 0.65 0.95 0.66 0.63 1.11 0.71 0.96 0.34 0.91 0.81 0.74 1.12 0.98 1.03
22.5 25.1 26.7 27.8 27.7 26.4 0.8 22.9 27.5 28.7 1.5 18.4 22.9 21.7 21.1 25.4 23.5 25.4 27.3 27.0 27.6 25.6 20.7 26.0 24.1 21.4 7.2 24.8 25.6 17.6 29.3 14.3 16.5
1.18 1.86 1.22 1.89 2.02 1.57 0.11 0.99 1.79 1.99 0.23 0.85 1.48 1.09 1.18 2.01 2.14 1.34 1.11 1.29 1.19 1.07 0.87 1.97 1.36 1.38 0.48 1.62 1.55 1.47 2.13 1.14 1.28
1.25 0.95 1.23 0.98 1.29 1.21 0.03 1.34 0.97 1.15 0.06 0.83 1.25 1.20 1.12 1.14 0.67 1.69 1.40 1.35 1.18 1.20 0.84 1.06 1.31 0.88 0.30 1.03 1.07 0.81 1.23 0.51 0.57
0.57 0.55 0.57 0.41 0.66 0.54 5.00 0.53 0.52 0.63 1.35 0.82 0.63 0.59 0.59 0.46 0.59 0.39 0.41 4.69 0.63 0.54 0.66 0.51 0.63 0.79 0.50 0.47 0.53 0.52 1.22 0.69 0.65
0.50 0.33 0.37 0.25 0.41 0.35 1.33 0.43 0.27 0.31 1.37 0.68 0.41 0.44 0.45 0.36 0.35 0.38 0.33 0.37 0.39 0.43 0.52 0.33 0.45 0.51 0.63 0.30 0.32 0.37 0.31 0.53 0.52
27.0 36.8 30.6 36.4 30.2 35.4 17.8 32.5 37.6 36.2 24.7 32.6 37.8 28.4 31.0 36.8 33.4 ND 33.4 31.1 24.0 30.4 ND 36.6 28.2 31.0 24.2 35.6 33.2 36.6 33.2 34.6 33.0
78.5 86.8 75.9 95.0 79.8 79.5 80.9 80.6 94.5 89.3 82.8 87.5 82.6 86.6 36.5 81.3 86.2 87.2 85.9 85.2 81.0 80.6 82.8 86.8 80.0 86.7 85.1 78.9 88.1 90.8 85.5 88.0 88.3
0.66 1.18 0.84 1.57 0.76 0.84 0.75 0.69 1.53 1.26 0.87 0.90 0.63 0.75 0.81 1.04 1.12 1.04 0.89 0.83 0.59 0.64 0.84 1.25 0.68 1.43 0.90 1.46 1.32 1.55 1.09 1.19 1.15
0.60 0.41 0.64 0.78 0.81 0.70 1.36 1.51 1.26 0.99 0.92 0.84 0.8 1.26 1.22 1.08 1.99 1.97 2.23 2.29 2.51 2.09 0.51 1.65
25.6 22.3 31.1 25.7 22.0 21.7 28.8 36.9 27.6 26.1 24.2 18.4 18.8 25.0 23.7 27.7 40.8 27.6 37.6 40.8 37.6 34.1 3.2 35.1
1.46 1.01 1.87 0.99 61.57 0.94 39.47 2.44 1.84 1.70 1.39 0.88 0.91 1.62 1.70 1.83 3.20 2.93 3.55 3.60 3.78 3.07 0.45 2.69
1.65 1.25 1.46 0.79 0.85 0.68 1.13 1.42 1.01 1.01 0.99 0.79 0.74 1.04 0.99 1.32 1.85 1.14 1.59 1.75 1.61 1.44 0.15 1.52
0.58 0.44 0.33 0.52 0.95 0.59 0.56 0.51 0.23 0.35 0.59 1.00 0.86 0.50 0.57 0.50 0.47 0.49 0.45 0.41 0.47 0.48 1.76 0.53
0.35 0.37 0.27 0.29 0.40 0.44 0.29 0.22 0.30 0.34 0.39 0.55 0.55 0.33 0.36 0.32 0.20 0.27 0.20 0.19 0.20 0.22 2.27 0.23
33.7 39.0 36.0 29.0 30.0 32.0 35.6 39.3 34.0 ND 33.0 24.9 24.9 34.0 31.0 30.0 40.5 40.5 44.0 44.0 43.0 44.0 28.0 36.0
91.1 90.7 91.1 87.0 81.4 65.8 89.5 93.6 91.4 90.1 86.3 59.6 71.1 89.7 89.0 87.6 92.1 92.7 94.4 94.6 95.6 92.2 82.6 86.4
1.49 1.37 1.32 1.19 0.97 1.59 2.59 2.51 1.89 1.57 1.51 1.02 1.10 1.77 3.30 1.63 2.44 2.73 3.23 3.38 3.29 2.78 1.35 1.82
2.36 1.38 2.24 148.4 28.9 436.1 0.39 12.26 0.96 0.66 3.90 2.35 0.46 5.25 1.04 1.57 5.68 3.34 16.00 42.14 83.0 0.57 1.18 0.63 1.72 0 . 9 1 7.17 0.34 0.69 1.14 250.7 16602 577.9 26.80 588.4 40.40 0.63 1.41 1.06 0 . 4 1 0.76 0.59 1.45 2.66 1.94 0.43 1.10 1.02 1.26 2.22 3.11 2.13 1.61 1.29 0.26 1.01 0.51 0.25 0.64 0.40 0.29 0.66 0.88 0.30 0.54 0.60 0.50 1.06 1.40 3 . 0 1 3.05 7.88 0.86 3.16 1.04 18.88 12.63 37.44 37.00 8.59 114.6 1.53 4.17 4.93 0.86 3.40 2.35 2.82 5.02 6.87 5.00 51.71 11.92 29.69 269.9 83.15 22.11 393.2 57.89 8.45 506.0 1.38 1.50 0.36 0.86 0.08 0.37 0.29 2.51 0.26 1.82 0.43 2.51 0.58 4.21 0.50 3.12 0.40 2.29 0.92 6.01 0.79 2.93 0.96 2.50 0.94 2.93 1.56 14.15 0.73 8.69 0.75 4.66 2 . 4 1 20.03 1.39 6.49 1.25 5.22 1.78 8.91 2.14 10.97 13.61 19.23 1.32 1.75
4.39 1.31 0.27 0.49 0.81 1.19 0.70 1.17 0.78 0.55 1.20 0.73 0.97 1.28 1.79 0.69 1.02 2.48 1.87 1.80 2.30 2.84 9.65 1.74
# = Sample number. Depth = sample interval midpoint well depth (m). Columns keyed to gasoline range compounds identified in Figure 12:PI1 - PARAFFIN INDEX 1 = peaks (12+15)/(16+17+18); HV - HEPTANE VALUE = peaks 19/(sum of peaks 11 to 21 ); Q = 8/9; R = 19/21 ; S = 7/10; T = 21/25; U = 11/10; V = 1/2; W = 7/8; API = API gravity in degrees. EXTRACT total solvent extract yield. %HC > 210°C fraction % hydrocarbons. S/A > 210°C fraction saturate hydrocarbon/aromatic hydrocarbon ratio. Pr/Ph = pristane/phytane; 17/Pr = nC17/pristane; 18Ph = nC18/phytane. Columns keyed to steranes identified in Figure 7: D/R = peaks 6/14; S/R Ster = 20/23; ~ , R = 21/23; 27 = (14/(14+19+23)) x 100; 28 = (19/(14+19+23)) x 100; 29 = peaks (23/(14+19+23)) x 100.
18/Ph
D/R Ster S/R 1 ~ / R 2
27
28
29
23/30
27/30
29/30
Tsf'rm Terp S/R
8.11 10.44 3.13 3.44 4.21 3.29
4.63 3.00 2.22 6.40 4.75 5.82
1.13 1.18 0.99 0.93 1.21 1.44
1.04 1.09 1.08 0.70 1.21 1.02
19.4 21.4 20.3 12.5 22.8 19.3
26.5 15.7 9 12.5 22.8 17.5
54.1 62.9 70.7 75 54.4 63.2
0.03 0.03 0.01 0.05 0.04 0.06
0.34 0.24 0.37 0.32 0.31 0.28
0.74 0.50 0.52 0.54 0.49 0.40
0.61 0.80 0.60 0.83 0.71 0.73
1.48 1.43 1.45 1.50 1.43 1.55
1.46 1.41 1.26
1.86 1.83 1.30
2.77 3.42 2.67
1.00 1.02 0.80
0.71 0.97 0.76
36.0 18.0 31.2 20.8 3 4 . 1 16.4
46.0 48.0 49.5
1.75 1.11 0.84
0.23 0.22 0.18
0.51 0.33 0.34
1.16 1.65 1.18
2.16 1.42 1.86
0.70 0.61 0.64 0.87 0.50 0.56 0.67 0.91 0.87 0.62 0.80 0.76 0.55 0.95 0.86 0.51 0.60 1.03 0.84 0.72 0.48 0.65 0.52 0.77 0.58 0.77 0.65 0.78 0.75 1.04 0.81 0.72 0.62
1.84 3.15 2.48 3.00 3.06 2.64 1.40 1.47 2.96 3.48 1.35 2~20 2.43 1.54 1.77 3.56 3.37 1.39 2.06 1.98 2.71 2.12 2.38 2.76 2.28 2.54 2.10 2.86 2.88 2.67 3.10 2.06 2.15
1.30 1.92 1.60 2.54 1.57 1.75 0.86 1.24 2.24 2.12 1.11 1.56 1.51 1.28 1.34 1.93 1.92 1.29 1.60 1.33 1.38 1.38 1.61 2.15 1.35 1.69 1.27 2.15 2.06 2.54 2.44 1.41 1.28
0.37 0.54 0.23 1.70 0.24 0.33 0.44 0.72 1.44 0.67 0.58 0.54 0.42 0.93 0.68 0.40 0.37 0.71 0.66 0.48 0.36 0.32 0.45 0.84 0.32 0.60 0.29 1.02 1.05 0.96 0.35 0.44 0.48
0.80 0.87 0.98 0.97 1.07 0.94 1.00 1.01 0.97 0.98 0.99 0.91 0.92 0.98 0.88 0.99 0.86 0.80 0.86 0.87 0.97 0.93 0.94 1.06 0.80 0.88 0.88 0.8 0.79 0.81 0.76 0.72 0.67
0.65 0.79 0.8 0.72 0.67 1.05 0.98 1.03 1.33 1.17 0.97 0.96 0.86 0.78 0.98 0.97 0.95 0.52 0.74 0.80 0.98 0.99 0.78 0.90 0.79 0.92 0.91 0.76 0.88 0.94 0.93 0.78 0.64
35.7 31.8 40.2 27.2 40.4 39.4 38.6 42.1 29.5 43.6 38.6 33.9 38.8 31.9 31.6 39.1 40.0 38.6 27.9 33.4 32.7 40.7 33.2 32.9 38.7 32.5 34.8 30.6 28.6 31.7 34.4 33.2 27.6
14.1 13.6 15.1 13.6 13.5 15.0 16.4 14.0 13.9 14.6 13.9 14.5 13.6 15.0 16.8 13.6 13.4 15.0 23.6 15.6 16.1 15.3 17.1 14.4 12.3 13.6 14.3 11.7 11.3 11.3 12.2 10.7 9.8
50.2 54.6 44.7 59.2 46.1 45.6 45.0 43.9 56.6 50.8 47.5 51.6 47.6 53.1 51.6 47.3 46.6 46.4 48.5 51.0 51.2 44.0 49.7 52.7 49.0 53.9 50.9 57.7 60.1 57.0 53.4 56.1 62.6
0.45 0.44 0.34 0.69 0.46 0.55 0.62 0.62 0.96 1.14 0.68 0.48 0.55 0.39 0.26 0.57 0.63 0.45 0.30 0.35 0.34 0.33 0.32 0.55 0.45 0.64 0.28 0.70 0.54 0.68 0.74 0.65 0.78
0.36 0.27 0.30 0.25 0.28 0.32 0.31 0.34 0.28 0.36 0.37 0.28 0.44 0.35 0.40 0.35 0.31 0.31 0.35 0.36 0.45 0.25 0.32 0.29 0.38 0.35 0.29 0.28 0.28 0.26 0.36 0.34 0.29
1.27 0.78 1.17 0.62 0.90 1.01 0.92 0.96 0.86 0.99 1.22 0.95 0.92 0.76 0.97 1.02 0.97 0.93 0.78 1.01 1.06 1.08 0.77 0.68 0.90 0.99 0.90 0.76 0.72 0.61 0.78 0.77 1.10
0.41 1.05 0.58 2.38 0.61 0.60 0.52 0.32 1.78 1.00 0.47 0.48 0.55 0.55 0.34 0.77 0.83 0.33 0.46 0.41 0.37 0.32 0.47 1.26 0.43 0.67 0.38 1.57 1.29 1.68 0.89 1.04 0.94
1.71 1.53 1.48 1.56 1.54 1.48 1.46 1.45 1.64 1.67 1.54 1.28 1.37 1.52 1.37 1.29 1.33 1.53 1.31 1.37 1.54 1.61 1.60 1.59 1.88 1.39 1.48 1.46 1.46 1.48 1.42 1.46 1.38
1.47 1.20 1.17 0.97 0.75 1.05 0.62 0.75 0.82 0.82 0.83 0.81 0.79 0.68 0.70 0.68 0.88 0.76 1.01 0.87 0.98 0.90 0.73 0.95
1.41 1.20 1.83 2.23 2.27 2.30 1.78 2.68 1.39 1.04 1.63 0.99 0.99 1.68 1.91 1.83 2.55 3.16 4.38 4.14 4.69 3.91 1.47 4.08
1.66 1.35 2.03 2.10 2.12 2.20 0.90 1.38 0.92 0.81 0.97 0.59 0.58 0.86 0.98 0.94 1.47 1.67 2.75 2.22 2.72 2.16 0.78 2.36
3.41 2.02 3.90 1.72 1.56 1.90 1.58 1.73 3.17 4.00 0.95 0.57 0.62 1.81 1.54 0.97 1.85 2.08 2.24 2.21 2.34 1.78 0.74 1.89
0.86 0.89 1.14 1.01 1.17 1.10 1.17 1.09 1.34 1.21 0.78 0.74 0.76 1.09 1.25 1.1 1.19 1.19 1.43 1.37 1.38 1.37 1.05 1.17
0.74 0.52 0.60 0.82 0.50 0.83 1.34 1.30 1.19 1.30 0.73 0.81 0.67 0.98 1.24 1.08 0.94 1.26 1.03 1.00 0.92 1.03 1.06 0.83
30.3 30.3 23.0 15.8 16.0 19.8 26.0 24.0 21.5 25.0 22.0 25.4 24.6 19.2 23.2 21.9 20.4 21.0 25.5 24.0 24.0 26.2 22.1 16.9
16.4 18.3 19.5 13.9 17.0 14.8 15.0 13.0 20.4 15.3 8.9 9.6 8.9 17.0 17.0 15.8 18.8 18.4 17.5 16.2 16.5 15.9 16.2 19.3
53.3 51.4 57.5 70.3 67.0 66.4 60.0 62.0 58.1 59.7 69.1 65.0 66.5 63.8 59.8 62.3 60.8 60.6 57.0 59.8 59.5 57.9 61.7 63.8
0.07 0.10 0.05 0.06 0.09 0.14 0.08 0.09 0.06 0.11 0.12 0.04 0.03 0.05 0.03 0.04 0.06 0.05 0.07 0.06 0.06 0.07 0.02 0.03
0.34 0.34 0.23 0.26 0.30 0.35 0.40 0.43 0.17 0.13 0.41 0.30 0.26 0.19 0.19 0.22 0.20 0.19 0.19 0.19 0.18 0.20 0.17 0.17
0.49 0.69 0.54 0.48 0.36 0.43 0.71 0.73 0.47 0.31 0.66 0.59 0.59 0.53 0.52 0.62 0.43 0.56 0.43 0.44 0.42 0.46 0.53 0.40
0.41 0.63 0.50 1.00 1.09 0.94 1.12 1.16 1.10 1.03 0.69 0.41 0.30 0.96 0.63 0.52 1.00 1.00 1.46 1.32 1.38 1.18 0.46 1.08
1.39 1.42 1.45 1.46 1.31 1.28 1.38 1.31 1.54 1.46 1.27 1.41 1.45 1.45 1.42 1.42 1.52 1.60 1.40 1.41 1.44 1.44 1.43 1.47
Columns keyed to terpanes identified in Figure 6:23/30 = peaks aft; 27/30 = peaks d/f; 29/30 = peaks e/f; Ts/Tm = peaks c/d; S/R Terp = peaks j/k; H/M = f/g; HP = carbon number prominence among external hopanes, peaks h-q, on m/z 191 mass chromatograms, N = no prominence, 34 = C34 hopanes, 35 = C35 hopanes prominent. ND - no data. 1029 sterane S/R thermal maturity indicator determined from GC- MS-MS experiments from m/z 400.40000 = > 217.2000 transitions for select samples are #550 = 1.08; #7597 = 1.02; #552 = 1.06; #755 = 1.22; #1273 = 1.02; #800 = 0.95; #1288 = 1.19; #1289 = 1.45. 2C29 sterane ~ / R thermal maturity indicator determined from GC- MS-MS experiments from m/z 400.4000 = > 217.2000 transitions for select samples are #550 = 1.29; #7597 = 1.07; #552 = 0.75; #755 = 1.76; #1273 = 0.91 ; #800 = 0.97; #1288 = 1.18; #1289 = 1.23.
262
K.G OSADETZ, P.W. BROOKS and L.R. SNOWDON
Solvent extract data (Table 4) is most c o m m o n from starved basinal settings where thermally mature samples from either Brightholme member (informal) bituminous mudstones (7097, 7098) or Ratner Member (informally restricted) dolomudstone-anhydrite laminites (7099, 7100) have distinctive compositions - most strongly reflected by their nC1JPr, nCls/Ph, terpanes and steranes (Table 4). A C34 hopane prominence is sometimes observed, but is not consistently d e v e l o p e d . T h e r m a l l y mature extracts have very high DIA/REG. All mature samples have anomalously high Ts/Tm and C29 sterane maturity ratios, commonly even higher than those of nearby oil pools. Mature basinal sample C23/C30 ratios are relatively high, between 0.20 and 0.50, compared to immature starved basin sources (6854, 6908). Samples 6854 and 6744, from immature basinal and platformal maximum flooding surface depositional settings, respectively, have low C23/C30. Sample 6744 has a pronounced C34 hopane promi-
nC17
nence, unlike 6854 which has a C31 hopane prominence. Generally Winnipegosis sources exhibit wide Pr/Ph variation, but all Upper Member-Ratner Member sources have Pr/Ph < 1.1, and only the Lower Member platformal sources (6785, 6786) have higher Pr/Ph. Platformal and platform marginal sources, including the Alpha and Beta lime mudstones (c.f. Ehrets and Kissling, 1987), also have lower nC17/Pr for a given nCi8/Ph than basinal sources. Winnipegosis extracts cannot be distinguished easily from other Devonian or Carboniferous sources using the SFGC alone, except when they have Pr/Ph < 1, and lack the even-odd predominance that characterizes Lodgepole sources. Bituminous and radioactive Bakken shales contain both "non-degraded" L e i o s p h a e r i d i a and T a s m a n i t e s unicellular marine alginite, with lesser amounts of acfitarchs, terrestrial spofinite, and minor vitifinite and inertinite, and "degraded" macerals, predominately bituminites (Stasiuk et al., 1990).
#6388
#6377
YEOMAN SOURCE 3109.4m
LOWER BAKKEN SOURCE 1829.3m C17 Pr
/
tO"
15'
20"
~ L _ . l 25' 30' 35' Time (mtn)
I
.t
40"
• . 45'
50'
55"
60'
t0'
15'
20"
25'
30" 3dS' T~lm (mtn)
40"
Ph
#6744 nC17
5033"
9627
50"
55"
60"
#6379
1
WlNNIPEGOSlS SOURCE 2700.7m
45"
LODGEPOLE SOURCE 2071.3m Pr
Ph
nC19
,rt f
i
I
I
; J 506i"
t0"
t5'
20'
25"
30' Time
35" (mln|
40'
45'
50'
55'
60'
t0"
i5'
20'
25'
30" ~" Time (rain)
40'
46'
50'
55"
60'
Fig. 5. Source rock solvent extract saturate fraction gas chromatograms. Sample numbers and stratigraphic positions are described in Table 3. Pristane (Pr), phytane (Ph) and select n-alkane peaks are identified. Prominent peaks eluting with a regular frequency are n-alkanes.
263
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
Rock-Eval and gross extract compositional characteristics indicate all C a n a d i a n B a k k e n extracts are immature to marginally mature (Table 2, Osadetz and Snowdon, in review). They have Pr/Ph always > 1.0 and generally > 1.1 with SFGC's lacking any predominance (Fig. 5, Table 4). Bakken C23]C30 are generally > 0.6 and always > 0.3 (Table 4) - values generally higher than those in other source rock formations, although some poorer Bakken source rocks (6328, 6334) are comparable to mature Winnipegosis samples (6908). Bakken extracts show no prominence among the hopane homologous group (Fig. 6). Bakken DIA/REG is < 1, but increases with higher Ts/Tm to exceed one (Fig. 7, Table 4). L o d g e p o l e organic material is predominantly an orangebrown fluorescing, mesh-like matrix bituminite with lesser marine alginite (L.D. Stasiuk, p e r s . c o m m . , 1989), while palynological preparations are dominated by amorphous kerogen. These immature to marginally mature source rocks have solvent extracts characterized by SFGC's with low Pr/Ph, < 1, and a pronounced even-odd predominance (Fig. 5, Table 4). C23/C30 is < 0.3, but DIA/REG < 1; C23 tricyclic/C24 tetracyclic terpane r a t i o > 1, and a C35 h o p a n e p r o m i n e n c e distinguishes them from other formations (Figs. 6, 7, Table 4). Lodgepole and Bakken extracts from the same wells (1415-002- 23W2 and 1A-02-006-25W2, Table 4) have comparad
#6380
ble compositions, with some exceptions. C29 sterane maturity ratios are consistently higher in Lodgepole samples from the same well where structural and stratigraphic relationships require identical thermal histories. There is a similarity between D I A / R E G sterane and Ts/Tm in the same well. Within these wells, Lodgepole and Bakken extracts are best distinguished using the C35 hopane prominence and slightly lower Lodgepole C23/C30 ratio (Table 4). OIL FAMILIES CRITICAL COMPOSITIONAL CRITERIA
Oil pools (Fig. 4, Table 5) are divided into four families using multiple compositional criteria including: pristane/phytane (Pr/Ph) ratio, n-alkane predominance, C23 tricyclic/C3o pentacyclic terpane (Cz3/C30) ratio and prominence amongst extended hopanes (Table 4). Pools occurring stratigraphically b e l o w the B a k k e n all have C23/C30 < 0.20 and a strong 17cz(H)-tetrakishomohopane (C34 hopane) prominence (Fig. 8). These can be further divided into a group distinguished by low Pr and Ph, relative to faster eluting n-alkanes nCl7 and nCi8, a strong odd-even predominance among n-alkanes between Cj5 and C20, and a low relative abundance in higher carbon number n-alkane homologues (Fig. 9, Table 6). These
f
a
ORDOVICIAN SOURCE
#6954
UPPER BAKKEN SOURCE
1732.5m
r
1833.0m
h
h
C
I
I
k
~,,J
J
J
i
C34,s L_ Pq
k Im no Pq
' If
.#6744 WlNNIPEGOSIS SOURCE 2700.7m
#6378SOURCE LODGEPOLE 2066.2m
e
If
i jI IJ
J
C
I
II
C35,s I
[
,i
, ............
°
p/
.......
Fig. 6. Source rock solvent extract m/z 191 (terpane) mass chromatograms. Samples described in Table 3. Annotated terpane compounds are: a = C23 tricyclic terpane; b = C24 tetracyclic terpane; c = Ts [18~(H)-trisnorneohopane]; d = Tm [17~(H)-trisnorhopane], C27 trisnorhopane; e = 17c((H)-norhopane, C29 norhopane; f = 17~(H)-hopane, C3o pentacyclic terpane (P.T.); g = moretane; h = (20S) 17cc(H)-homohopane, C31 P.T; = (20R) 17cc(H)-homohopane, C31 P.T.; j = (20S) 17c~(H)-b shomohopane, C32 P.T.; k = (20R) 17~(H)-bishomohopane, C32 P.T.; I = (20S) 17c~(H)trishomohopane, C33 P.T.; m = (20R) 17c((H)-trishomohopane, C33 P.T.; n = (20S) 17~(H)-tetrakishomohopane, C34 P.T.; o = (20R) 17~(H)-tetrakishomohopane, C34 P.T.; p = (20S) 17c~(H)-pentakishomohopane, C35 P.T.; q = (20R) 1 7c~(H)-pentakishomohopane, C35 P.T.
264
K.G OSADETZ, P.W. BROOKS and L.R. SNOWDON
are Family A oils. The other group has abundant Pr and Ph and complex SFGC's (Fig. 9). These are Family D oils. They can be s u b d i v i d e d into oils from Elk P o i n t G r o u p Winnipegosis pinnacle reefs (D2), with higher nCiT/Pr ratios for a given nC=s/Ph ratio compared to otherwise similar oils that occur in overlying Saskatchewan and Manitoba groups' strata, (D 0 (Fig. 10, Table 6). D 2 oils and Dl oils in Madison reservoirs have Pr/Ph < 1.0, while DI oils in Birdbear pools have Pr/Ph > 1.1. Three oils have C23/C30 > 0.80, without any prominence among the hopane homologues, Pr/Ph > 1.50 and S F G C ' s lacking any predominance (Figs. 8, 9, Table 6). These form a r e v i s e d F a m i l y B all o c c u r r i n g in B a k k e n r e s e r v o i r s . Remaining oils have C23/C30 > 0.20 generally accompanied by a strong 17ct(H)-pentakishomohopane (C35 hopane) prominence, Pr/Ph < 1.1, and a pronounced (>nC20) even n-alkane predominance (Figs. 8, 9). These form a revised Family C. Families B and C can be unambiguously identified on a C23/C30 versus Pr/Ph cross-plot (Fig. 11), while Families A and D occupy a third field and can be mutually distinguished by referring to their SFGC's (Fig. 9).
1112
#6380
THERMAL MATURITY Numerous compositional traits vary systematically with thermal maturity. In contrast to general practice ( e . g . , van Graas, 1990), it was concluded that 18c¢(H)-trisnorneohopane/17cz(H)-trisnorhopane (Ts/Tm) most effectively described relative maturity variations within oil families through the main hydrocarbon generation stage (approximately 0.7-1.2% vitrinite reflectance). Ts/Tm varies systematically with S/A HC ratio, d e n s i t y (API gravity), nCls/Ph, 3methylpentane/n-hexane (3MCs/nC6) or DIA/REG, particularly in families C and D which exhibit large physical and compositional variations (Table 6). C29 sterane (Fig. 14) maturity indicators are less effective at indicating relative maturity variations among oil pools, particularly in Family D, where currently inexplicable, anomalously high S/R ratios are commonly observed. Some anomalies are attributable to co-eluting compounds, but GC-MS-MS experiments indicate that S/R ratios sometimes exceed isomerization reaction equilibrium values on m/z 400.4000 => 217.2000 fragmentograms (Table 6). Gasoline range (Fig. 12) thermal maturity indicators (Thompson, 1983), including Heptane Value, Paraffin Index 1,
ORDOVICIAN S O U R C E
2161.Om
1732.5m
11+12 6 ,^[
2
16
1:°21
,
19 ,~=
#6908
WINNIPEGOSIS SOURCE 974.4m
!
111+12 I I I loll
s 2
tl,
#6394
LOWER BAKKEN SOURCE
=
i
I,,iiltl 'i
. . . .
#6378
LODGEPOLE SOURCE 2066.2m
12 1 11 13 u
21
6I
I
Fig. 7. Source rock solvent extract m/z 217 (sterane) mass chromatograms. Samples are described in Table 3. Annotated sterane compounds are: , 2 - C21 sterane; 3 = C21 sterane; 5 = C22 sterane; 6 = 13~(H), 17ct(H)-diacholestane (20S); 7 = 1313(H), 17~(H)-diacholestane (20R); 10 = 5ct(H), 14c~(H), 17o~(H)-cholestane (20S); 11 = 5(x(H). 14~(H), 17~(H)-cholestane (20R); 12 = 24-ethyl-13~(H), 17ct(H)-diacholestane (20S); 13 = 5ct(H), 14~(H),17~(H)-cholestane (20S); 14 = 5c~(H), 14c~(H), 17o~(H)-cholestane (20R); 15 = 24-ethyl-13~(H), 17ct(H)-diacholestane (20R); 16 = 24-methyl-5c~(H), 14ct(H), 17ct(H)-cholestane (20S); 17 = 24-methyl-5c~(H). 14~(H), 17~(H)-cholestane (20R); 18 = 24-methyl-5ct(H), 14~(H), 17~(H)-cholestane (20S); 19 = 24-methyl-5~(H), 14~(H), 17o~(H)-cholestane (20R); 20 = 24-ethyl-5o~(H), 14(x(H), 17c~(H)-cholestane (20S) and may contain as yet unidentified co-eluting compounds; 21 = 24-ethyl-5~(H), 14t3(H), 1713(H)-cholestane (20R); 22 = 24-ethyl-5(~(H), 14~(H), 17~(H)-cholestane (20S); 23 = 24-ethyl-5o~(H), 14~(H), 17~(H)-cholestane (20R).
265
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
n-hexane/methylcyclopentane, n-heptane/methylcyclohexane, show generally poor correlation or sensitivity to other maturity dependent compositional ratios (Fig. 13, Table 6). ADDITIONAL COMPOSITIONAL CHARACTERISTICS Additional traits follow oil families defined above, but are commonly maturity dependent. High maturity Family C oils often have compositional ratios like those of other families. Diasterane/regular sterane (DIA/REG) ratios are most important (Fig. 14, Table 6). Following preferred mechanisms of diasterane formation (Rubinstein et al., 1975, Sieskind et al., 1979) DIA/REG was initially used (Brooks e t al., 1987) to divide Williams' (1974) Type II oils and to infer that the subdivisions were probably from different sources. Family C DIA/REG was < 1.0, and with one exception was < 0.8 when Ts/Tm was < 1.1. This suggested a "carbonate" source rock. Family C DIA/REG increases with thermal maturity so that DIA/REG is always > 0.8 when Ts/Tm > 1.1 (Table 6). Family B, high maturity (Ts/Tm > 1.1), low density oils have DIA/REG > 2.0. Progressive increase in DIA/REG with
#550
increasing maturity is attributed to greater diasterane resistance to cracking (van Graas, 1990; Seifert and Moldowan, 1978), but Family B DIA/REG is always greater than Family C DIA/REG, for oils of comparable Ts/Tm (Table 6). This suggests that a source dependent "clastic"-"carbonate" distinction persists even at higher maturities. Less well understood are the high DIA/REG rmios of Family A and D oils (Fig. 14, Table 6). DIA/REG > 2.0 for all Family A oils. Family D shows a wide DIA/REG variation at low Ts/Tm. Some samples are comparable to Family C oils while others are as high as Family A. High ratios might be thought indicative of "clastic" source rocks, but stratigraphic, petrographic and solvent extract data discussed below preclude such an association. Longman and Palmer (1987) have suggested that clay minerals may not be the only control on sterane rearrangement. C29 norhopane/C30 hopane (C29/C30) ratio v e r s u s DIA/REG ratio (Fig. 15) and DIA/REG v e r s u s Pr/Ph (Fig. 16) crossplots provide other ways of distinguishing most Family C oils from other oil families. Family C C29/C30 ratios are generally higher and DIA/REG ratios are generally lower than other oil If
#554
LAKE ALMA B I G H O R N POOL FAMILY "A" OIL
R O N C O T T B A K K E N POOL FAMILY "B" OIL
hi
! ,
ii
. . . .
i
.
.
.
.
.
,
,
,
,
j
.
.
.
.
.
.
.
.
.
E
.
.
.
.
.
.
.
.
.
i
.
.
.
.
.
,
,
c3,'s ,
,
i
1
k I mn
o
I
. . . .
f
#551
#511
H U M M I N G B I R D B I R D B E A R POOL FAMILY "D" OIL
K E N O S E E T I L S T O N POOL FAMILY "C" OIL h
035's Jk
C34's
IL, J
n b
c,
Fig. 8. Oil sample > 210°C boiling point m/z 191 (terpane) mass chromatograms. Samples are described in Table 5. Terpane compounds annotated a-q as reported in the caption to Figure 6.
266
K.G OSADETZ, P.W. BROOKS and L.R. SNOWDON
#515 ROCANVILLE B A K K E N POOL FAMILY "B" OIL
#549 O U N G R E WEST B I G H O R N POOL FAMILY"A"OIL
i t336 1
nC19 "'
nC19 ~h /
r~
5.
iO'
t5'
20"
25'
30' 35' Time (min)
40'
45'
50'
55'
60'
#800 TABLELAND W I N N I P E G O S I S POOL FAMILY "D" OIL
504i
lO'
15'
20'
25'
20'
25'
45'
50'
55'
60'
nC20 Ph
/
#557 NEPTUNE R A T C L I F F E POOL FAMILY "C" OIL
~r f
~_La 15'
40'
(min)
8972 ;
I h
10'
35'
Time
IC20
5062 •
30'
30' 35' Time (mini
40'
45'
50'
55"
60'
5047
10'
i5'
2O'
25'
3o'
Time
35' (min)
40'
45'
50'
55'
60'
Fig. 9. Oil sample > 210°C boiling point Saturate Fraction Gas Chromatograms. Samples are described in Table 5. Pristane (Pr), phytane (Ph) and select n-alkane peaks are identified. Prominent peaks eluting with a regular frequency are n-alkanes.
families (Fig. 15), although higher maturity Family C oils overlap less mature Family D oils. Lower Pr/Ph and DIA/REG ratios in Family C oils also distinguish them from all but the least mature Family D oils (Fig. 16). Saturate/aromatic hydrocarbon (S/A HC) ratio generally increases with Ts/Tm, although at a much faster rate for Family D than for Family C (Fig. 17). Families A and B have too few members to establish clear S/A HC variations, although it appears that Family B follows Family C variations. C26:C27:C28 triaromatic steroid hydrocarbon compositions (m/z 231) also follow familial assignments and shall be reported elsewhere. Mixed compositional characteristics are rare. Freda Lake Ratcliffe pool (546) has a C34 prominence although its other compositional characteristics are typical of Family C (Figs. 10, 11, 15, 16). ALTERATION
Snowdon and Osadetz (1988b) showed GFGC's to be poor familial affinity indicators, but good biodegradation and water
washing indicators. Isopentane/n-pentane (Fig. 12, iCs/nCs), 3MCJnC6, nC]v/Pr and nCls/Ph ratios are commonly used biodegradation indicators, but depend on source rock composition, as shown by Family A oils, and thermal maturity, as shown by Family C oils (Table 6). We infer that significant biodegradation is restricted to a few Family C oils in the reported sample set. There is a positive correlation between iCs/nC5 and 3MCs/nC6 with a few outliers (Table 6). Two Family C samples, Redjacket (512) and Wapella (523), with the highest density and 3MCs/nC6, fall well below general nC~8/Ph v e r s u s Ts/Tm maturity variations indicating n-alkane depletion (Fig. 18). This was interpreted as biodegradation. Three other pools, Oungre (540), Virden Lodgepole A (725) and Lodgepole B (722) have lower than expected nCis/Ph for their thermal maturities (Fig. 18), but only the Virden Field samples have gasoline range indications of n-alkane depletion (Snowdon and Osadetz, 1988b). Moose Valley (596) Family C pool is a high density, low maturity oil with a high gasoline
OIL FAMILIES AND THEIR SOURCES IN CANADIAN WILLISTON BASIN
•
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Fig. 10. Select oil s a m p l e nC~8/Ph v e r s u s nC17/Pr cross-plot. Sample numbers are identified in Table 5. Differences in the variation of this ratio distinguish Winnipegosis pinnacle reef pools, Family D2, from Family D1 oils that originate from platformal and platform marginal sources and usually migrate into higher stratigraphic horizons. A best fit regression line to Family D2 data is nC~7/Pr = 1.71 (nC~8/Ph) + 0.08. Family C oils describe another linear trend intermediate to the two Winnipeg•sis sub-families. Family C oils with very high Ts/Tm thermal maturities tend to have slightly lower than expected nC~7/Pr, compared to less mature samples. The few Family B oils follow Family D~. Family A oils define an additional linear variation which is not shown here b e c a u s e the low relative a b u n d a n c e of acyclic isoprenoid compounds in those oils results in large values of these ratios. If plotted here, they would obscure the relationships among other families (Table 6).
•
WEIRHILL
25'
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OIL FAMILY A
•
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•
OIL FAMILY O
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Fig. 12. Gasoline range compositional fraction gas chromatogram ( G F G C ) for Weirhill 9 - 2 9 - 6 - 6 W 2 Bighorn G r o u p discovery well. Annotated compounds are: 1 = isopentane; 2 = n-pentane; 3 = 2,2dimethylbutane; 4 = cyclopentane; 5 = 2,3-dimethylbutane; 6 = 2methylpentane; 7 = 3-methylpentane; 8 = n-hexane; 9 = methylcyclopentane; 10 = benzene; 11 = cyclohexane; 12 = 2-methylhexane; 13 = 1,1-dimethylcyclopentane; 14 = 2,3 dimethylpentane; 15 = 3methylhexane; 16 = lcis,3-dimethylcyclopentane; 17 = l t r a n s , 3 dimethylcyclopentane; 18 = ltrans,2-dimethylcyclopentane; 19 = nheptane; 20 = lcis,2-dimethylcyclopentane; 21 = methylcyclohexane; 22 = 2 , 5 - d i m e t h y l h e x a n e ; 23 = 2,4-dimethylhexane; 24 = 2 , 2 , 3 trimethylpentane; 25 = toluene; 26 = 3-methylheptane; 27 = lcis,4dimethylcyclohexane; 28 = n-octane.
•
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Fig. 11. Oils sample 023 tricyclic/C30 pentacyclic terpane ratio v e r pristane/phytane ratio cross-plot. Empirical compositional ratios delimiting oil family variations at pristane/phytane = 1.1 and C23 tricyclic/C30 pentacyclic terpane ratio = 0.20 are indicated. Families A and D are mutually distinguished using saturate fraction gas chromatogram compositional characteristics shown in Figure 9. Sample 546, Freda Lake Ratcliffe pool, which has a C34 hopane prominence is indicated and discussed further in the caption for Figure 15. sus
Fig. 13. Cross-plot of Paraffin Index 1 v e r s u s Heptane Value showing boundaries of biodegradation and thermal maturity classes as inferred by Thompson (1983). Suggested class intervals are not considered indicative of thermal maturity for these samples. The field of biodegraded oils is consistent with other indications of biodegradation among low maturity oils, but high maturity oils like 722 and 725 from the Virden field have other indications of biodegradation, illustrated on the Ts/Tm v e r s u s C18/Ph cross-plot (Fig. 18), not reflected in the gasoline range composition. Sample 1312 exhibits no other indications of biodegradation.
K.G OSADETZ, P.W. B R O O K S and L.R. S N O W D O N
268
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range Factor 3 score and very low Paraffin Index 1 and Heptane Value that could be attributed to biodegradation (Fig. 13), although it follows non-biodegraded oils on several plots involving thermal maturity and c o m p o u n d s sensitive to biodegradation (Table 6). Wapella, Red Jacket, Moose Valley, and the two Virden Lodgepole pools are interpreted to be biodegraded, although Moose Valley (596) less so. Other families show no evidence for biodegradation. Family D variations of nCjv/Pr v e r s u s nCis/Ph are clearly attributable to either thermal maturity or source rock facies variations (Fig. 10, Table 6). Soluble compound concentrations, particularly benzene and toluene (Fig. 19, Table 6), are systematically depleted independent of thermal maturity and familial affinity suggesting that cyclohexane/benzene, 3-methylpentane/benzene and methylcyclohexane/toluene ratios are primarily controlled by water washing (Fig. 19). Biodegraded oils are usually strongly water washed but not all water washed oils are biodegraded, particularly in Family B and along oilfield province margins, which suggests a rough correlation between migration pathway length and water washing.
OIL SOURCE CORRELATION STRATIGRAPHIC ASSOCIATIONS
Family A oils occur in Upper Ordovician Bighorn reservoirs, the Pine Unit in the Cedar Creek Anticline (Fowler et al., 1986) and two Winnipegosis pools at Raymond, Montana (Leenheer and Zumberge, 1987) and Minton, Saskatchewan (Fig. 3). Family D oils occur in several formations in the interval including Winnipegosis pinnacle reefs and Ratcliffe Beds, Madison Group. In the United States, similar oils occur in the Saskatchewan and Manitoba Groups (Osadetz et a l . , 1990; Leenheer and Zumberge, 1987). Family D can be subdivided into (1) Winnipegosis reef and platform margin pools from basin sources and (2) pools in the Winnipegosis platform, and higher stratigraphic units attributed to platform source rocks using the n C J P r v e r s u s n C J P h diagram (Fig. 10). Family B oils occur in Bakken Formation reservoirs at Roncott, Daly and R o c a n v i l l e f i e l d s . P r o d u c t i o n from the B a k k e n Hummingbird pool, all Mississippian Madison pools and all Mesozoic oil fields in southeastern Saskatchewan and southwestern Manitoba is Family C oils.
OIL FAMILIES AND THEIR SOURCES IN CANADIAN W1LLISTON BASIN
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Fig. 15. C29 norhopane/C30 hopane (029/03o) ratio v e r s u s diasterane/regular sterane (DIA/REG) ratio cross-plot. There is a general decrease in 029/030 with increasing DIA/REG. Sample 546, Freda Lake Ratcliffe pool, is indicated. This sample has a 034 hopane prominence, like Family D oils, that may be due to a small component of mixing, because Family D oils have migrated into other nearby Ratcliffe pools.
•
Fig. 17. Trisnorhopane (Ts/Tm) thermal maturity ratio v e r s u s saturate/aromatic hydrocarbon ratio cross-plot. Notice the progressive increase of Family C and Family D saturate/aromatic ratio with increasing thermal maturity, but at different rates. Family B oils are not represented at lower thermal maturities, an observation attributed to expulsion threshold, while Family A oils show poor positive correlation.
OIL FAMILy A
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Fig. 16. Diasterane/regular sterane ratio v e r s u s pristane/phytane ratio cross-plot. Empirical compositional ratios delimiting fields of oil family variation over either the complete or partial thermal maturity range are indicated. Variations extending beyond the limits of reported data consider data from the United States that will be reported elsewhere. High maturity Family C oils and low maturity Family D oils have overlapping fields on this diagram.
Dow (1974) invoked anhydrite and halite formations as barriers to vertical migration to explain stratigraphic associations among oils and sources. Our study yields similar conclusions. Family A oils occur in the stratigraphic interval which i n c l u d e s M i d d l e and U p p e r O r d o v i c i a n k u k e r s i t e s . Winnipegosis pinnacle reefs contain only Family D oils and where similar oils occur in Mississippian reservoirs there is an obvious connection with Prairie salt-dissolution (Hartling et al., 1982) which suggests the Winnipegosis is the source of Family D oils. Family B oils are restricted to Bakken reser-
Fig. 18• Ts/Tm trisnorhopane thermal maturity ratio v e r s u s nC18/Ph cross-plot for oils whose source is Family C - - Lodgepole. Samples 540, 523, 512, 725, and 722 that fall below the general trend of increasing nC18/Ph with increasing Ts/Tm are indicated. Most of these samples have gasoline range characteristics suggesting n-alkane depletion and biodegradation, except for Sample 540, which shown no other indications of biodegradation. Sample 596, which shows strong gasoline range biodegradation characteristics plots within the trend of other non-degraded oils.
voirs and entirely absent from the Madison Group. Family C oils are a b s e n t from B a k k e n r e s e r v o i r s , e x c e p t in the Hummingbird structure, consistent with Bakken/Family B and L o d g e p o l e / F a m i l y C a s s o c i a t i o n s . B a r c h y n ( 1 9 8 4 ) has explained how these oils migrate into Mesozoic reservoirs. COMPOSITIONAL SIMILARITIES Stratigraphic associations tested using compositional criteria are generally successful• Yeoman kukersites, like Family A
K.G OSADETZ, P.W. BROOKS and L.R. SNOWDON
270
LODGEPOL E •
o L FAMILY A
UppER BAKKEN
LOWER B A K K E N
OH- FAMrLY B
m N Z
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YEOMAN WINNIPEG
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OIL FAMILY D
106
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:o; 10
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: I E L D OF
FAMILY ~ AND - =AMI Ly D OILS
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•
.
1. They have migrated long lateral distances within the Bakken Formation. Lodgepole Formation (Lower Mississippian) oils are the volumetrically most significant oil family and are characterized by higher C23/C30 accompanied by a C35 hopane prominence, low Pr]Ph and pronounced even-odd n-alkane predominance. These oils, too, have tended to remain within the stratigraphic group that is their source. ACKNOWLEDGMENTS
This project was funded by the Office of Energy Research and Development, Energy Mines and Resources, Canada; O.E.R.D. Project 6.1.1.04, Quantitative aspects of petroleum origin in the Western Canada Sedimentary Basin and by Geological Survey of Canada Projects 780003 and 730062. The authors are grateful for advice and guidance provided by the Joint Government-Industry Review Committee that oversees this project. Analytical support was provided by the staff of the Institute of Sedimentary and Petroleum Geology's organic geochemistry laboratories. The authors extend their appreciation to E. M. Northcott, R. G. Fanjoy and S. L. Achal. A u t h o r s are g r a t e f u l to the m a n a g e m e n t and staff of Saskatchewan Energy and Mines, Manitoba Energy and Mines, and the North Dakota Geological Survey for their assistance and support during sample collection and their constructive discussion of our interpretations. Altex Resources Ltd., Gulf Canada Resources Inc., Home Oil Company Ltd., Mark Resources Inc., Petro-Canada Resources Inc., Total Petroleum Canada Ltd., and their partners kindly supplied samples from more recent discoveries. Constructive reviews by Dr. J. A. Curiale, Dr. S. Creaney and Dr. N. J. McMillan improved the discussion. REFERENCES Bailey, N.J.L., Krouse, H.R., Evans, C.R. and Rogers, M.A. 1973b. Alteration of crude oils by waters and bacteria - evidence from geochemical and isotope studies. American Association of Petroleum Geologists, Bulletin, v. 57, no. 7, p. 1276-1290. Barchyn, D. 1984. The Waskada Lower Amaranth (Spearfish) oil pool, southwestern Manitoba. In: Oil and Gas in Saskatchewan, J.A. Lorsong and M.A. Wilson (eds.). Saskatchewan Geological Society Special Publication No. 7, p. 103-112. Brooks, P.W., Osadetz, K.G. and Snowdon, L.R. 1988. Geochemistry of Winnipegosis discoveries near Tablelands, Saskatchewan; In: Current Research, Part D. Geological Survey of Canada, Paper 88-1 D, p. 11-20. . . . . and _ _ 1987. Families of oils in southeastern Saskatchewan. In: Proceedings of the Fifth International Williston Basin Symposium. Bismark, North Dakota, June 15-17, 1987, C.G. Carlson and J.E. Christopher (eds.). Saskatchewan Geological Society, Special Publication No. 9, p. 253-264. Campbell, C. and Forbes, D. 1990. Sedimentology and hydrocarbon source potential of the Upper Devonian Saskatchewan Group of southeastern Saskatchewan. Manuscript report to Department of Supply and Services Canada contract 23294-9-0630/0 I-SG, 39p. and _ _ 1989. Sedimentology and hydrocarbon source potential of the Middle and U p p e r Devonian M a n i t o b a G r o u p of southeastern Saskatchewan. Manuscript report to Department of Supply and Services Canada contract 23294-7-0618/01-SG, 58p.
_
_
Clement, J.H. 1987. Cedar Creek: a significant paleotectonic feature of the Williston Basin. In: Williston Basin: Anatomy of a Cratonic Oil Province, M.W. L o n g m a n (ed.). D e n v e r : R o c k y M o u n t a i n A s s o c i a t i o n of Geologists, p. 323-336. Dembicki, H. Jr., and Pirkle, R.L. 1985. Regional source rock mapping using a source potential rating index. American Association of Petroleum Geologists, Bulletin, v. 69, no. 4, p. 567- 581. Dow, W.G. 1974. Application of oil-correlation and source-rock data to exploration in Williston Basin, American Association of Petroleum Geologists, Bulletin, v. 58, p 1253-1262. Edie, R.W. 1958. Mississippian sedimentation and oil fields in southeastern Saskatchewan. American Association of Petroleum Geologists, Bulletin, v. 42, no. 1, p. 94-126. Ehrets, J.R. and Kissling, D.L. 1987. Winnipegosis platform margin and pinnacle reef reservoirs, Northwestern North Dakota. In: Fifth International Williston Basin Symposium: Core Workshop Volume, June, 1987, D.W. Fischer (ed.). North Dakota Geological Survey, Miscellaneous Series 69, p. iv-31. Espitalie, J., Deroo, G. and Marquis, F. 1985. Rock Eval Pyrolysis and Its Applications: preprint; Institut Francais du Petrole, Geologie No. 27299, 72 p. English translation of La pyrolyse Rock-Eval et ses applications, Premiere, Deuxieme et Troisieme Parties. In: Revue de l'Institut Franqais du Petrole, v. 40, p. 563-579 and 755-784; v. 41, p. 73-89. Fischer, D.W. and Rygh, M.E. 1989. A synoptic overview of the Bakken Formation in portions of Billings, Golden Valley, and McKenzie counties, North Dakota. North Dakota Geological Survey, Report of Investigation, No. 89, 14p. Foster, C.B., Reed, J.D., Wicander, R. and Summons, R. 1989. Anatomy of an Ordovician oil-prone maceral: Gloeocapsomorpha prisca Zalessky 1917. In: Proceedings of the Macerals '89 Symposium, C.G. Thomas and M.G. Strachan (eds.). North Ryde, New South Wales: Commonwealth Certified and Industrial Research Organization Division of Coal Technology, Part 16, p. 1-9. _ _ , O'Brien, G.W. and Watson, S.T. 1986. Hydrocarbon source potential of the Goldwyer Formation, Barbwire terrace, Canning basin, Western Australia. Australian Petroleum Exploration Association, Journal, v. 26, p. 142-155. Fowler, M.G. 1992. The influence of Glococapsomorpha prioca on the organic geochemistry of oils and organic rich source rocks of Late Ordovician age from Canada. In: Early Organic Evolution: Implications for Mineral and Energy Resources, M. Schidlowski (ed.). Springer-Verlag, Berlin and Heidelberg, p. 336-356. _ _ , Abolins, R and Douglas, A.G. 1986. Monocyclic alkanes in Ordovician organic matter. In: Advances in Organic Geochemistry 1985, D. Leythaeuser and J. Rullk6tter (eds.). Pergamon Press, Oxford: Organic Geochemistry, v. 10, p. 815-823. and Douglas, A.G. 1984. Distribution and structure of hydrocarbons in four organic-rich Ordovician rocks. Organic Geochemistry, v. 6, p. 105114. Hartling, A., Brewster, A. and Posehn, G. 1982. The Geology and hydrocarbon trapping mechanisms of the Mississippian Oungre Zone (Ratcliffe Beds) of the Williston Basin. In: Fourth International Williston Basin Symposium, J.E. Christopher and J. Kaldi (eds). Saskatchewan Geological Society, Special Publication, No. 6, p. 217-223. Hoffmann, C.F., Foster, C.B., Powell, T.G. and Summons, R.E. 1987. Hydrocarbon biomarkers from Ordovician sediments and the fossil alga GIoeocapsomorpha prisca Zalessky 1917. Geochimica et Cosmochimica Acta, v. 51, p. 2681-2697. Jacobson, S.R., Hatch, J.R., Teerman, S.C. and Askin, R.A. 1988. Middle Ordovician organic matter assemblages and their effect on Ordovicianderived oils. American Association of Petroleum Geologists, Bulletin, v. 72, no. 9, p. 1090-1100. Kendall, A.C. 1976. The Ordovician carbonate succession (Bighorn Group) of southern Saskatchewan. Saskatchewan Department of Mineral Resources, Report 180, 185p. Kent, D.M. 1987. Mississippian facies, depositional history and oil occurrences in Williston Basin, Manitoba and Saskatchewan. In: Williston Basin: Anatomy of a Cratonic Oil Province, M.W. Longman (ed.). Denver: Rocky Mountain Association of Geologists, p. 157- 170.
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K.G OSADETZ, P.W. B R O O K S and L.R. S N O W D O N
Kohm, J.A. and Louden, R.O. 1982. Ordovician Red River of eastern Montana and western North Dakota: Relationships between lithofacies and production. In: Fourth International Williston Basin Symposium, J.E. Christopher and J. Kaldi (eds.). Saskatchewan Geological Society, Regina, p. 27, 28. and 1978. Ordovician Red River of eastern Montana and western North Dakota: relationships between lithofacies and production. In: 24th Annual Conference, D. Rehrig (ed.). Williston Basin Symposium the Economic Geology of the Williston Basin. Montana Geological Society, Billings, Montana, p. 99-117. Leenheer, M.J. 1984. Mississippian Bakken and equivalent formations as source rocks in the Western Canadian Basin. Organic Geochemistry, v. 6, p. 521-532. _ _ and Zumberge, J.E. 1987. Correlation and thermal maturity of Williston Basin crude oils and Bakken source rocks using terpane biomarkers. In: Williston Basin: Anatomy of a Cratonic Oil Province, M.W. Longman (ed.). Denver: Rocky Mountain Association of Geologists, p. 287-298. Lefever, J.A., Martiniuk, C.D., Dancsok, E.F.R. and Lund, D.F. 1991. Petroleum potential of the Middle Member, Bakken Formation, Williston Basin. In: Proceedings of the Sixth International Williston Basin S y m p o s i u m , J.E. C h r i s t o p h e r and F. Haidl (eds.). S a s k a t c h e w a n Geological Society, Special Publication 11, p. 74-94. _ _ , Lefever, R.D. and Anderson, S.B. 1987. Structural evolution of the central and southern portions of the Nesson Anticline, North Dakota. In: Proceedings of the Fifth International Williston Basin Symposium. Bismarck, North Dakota, June 15-17, 1987, C.G. Carlson and J.E. Christopher (eds.). Saskatchewan Geological Society, Special Publication No. 9, p. 147-156. Longman, M.W. and Palmer, S.E.,1987. Organic Geochemistry of mid-continent Middle and Late Ordovician oils. American Association of Petroleum Geologists, Bulletin, v. 71, p. 938-950. Manitoba Energy and Mines 1986. Manitoba's designated oil pools, Manitoba Energy and Mines, 4p. Martindale, W., Erkmen, U., Metcalfe, D. and Potts, E. 1991. Winnipegosis Buildups of the Hitchcock area, southeastern Saskatchewan - - a case study. In: Proceedings of the Sixth International Williston Basin S y m p o s i u m , J.E. C h r i s t o p h e r and F. H a i d l (eds.). S a s k a t c h e w a n Geological Society, Special Publication 11, p. 47-63. _ _ . , and MacDonald, R.W. 1989. Sedimentology and diagenesis of the Winnipegosis Formation (Middle Devonian) Tableland area, southeastern Saskatchewan. In: 1989 Core Conference: Geology and Reservoir Heterogeneity, J. ben Haan and T. Webb (eds.). Canadian Society of Petroleum Geologists, September 21-22, 1989, Calgary, p. 2-1 to 2-52. McCabe, H.R. 1963. Mississippian oil fields of Southwestern Manitoba. Manitoba Mines Branch, Publication 60-5, 50p. Meissner, EE 1978. Petroleum Geology of the Bakken Formation Williston Basin, North Dakota and Montana. In: 24th Annual Conference, D. Rehrig (ed.). Williston Basin Symposium - the Economic Geology of the Williston Basin. Proceedings of the Montana Geological Society, Billings Montana, p. 2(17-227. Osadetz, K.G. and Snowdon, L.R. (in review). Significant Palaeozoic petroleum source rocks, their distribution, richness and thermal maturity in Canadian Williston Basin, (southeastern Saskatchewan and southwestern Manitoba). Geological Survey of Canada, Bulletin. and Brooks, EW. (in review). Oil families, their sources and m i g r a t i o n p a t h w a y s in C a n a d i a n W i l l i s t o n B a s i n , ( s o u t h e a s t e r n Saskatchewan and southwestern Manitoba). Geological Survey of Canada, Bulletin. _ _ _ , Brooks, P.W. and Snowdon, L.R. 1991. Relationships amongst oil quality, thermal maturity and post- accumulation alteration in Canadian Williston Basin (southeastern Saskatchewan and southwestern Manitoba). In: Proceedings of the Sixth International Williston Basin Symposium, J.E. Christopher and E Haidl (eds.). Saskatchewan Geological Society, Special Publication No. l l, p. 293-311. _ _ , Goodarzi, E, Snowdon, L.R., Brooks, EW. and Fayerman, S. 1990. Winnipegosis pinnacle reef play in Williston Basin: oil compositions and effects of oil-based drilling muds on exploration geochemistry. In: Current Research, Part D. Geological Survey of Canada, Paper 90-1 D, p. 153-163. and Haidl, EM. 1989. Tippecanoe sequence: Middle Ordovician to lowest Devonian: vestiges of a great epeiric sea, Chapter 8. In: Western Canada Sedimentary Basin: A Case Study, B.D. Ricketts (ed.). Canadian -
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Society of Petroleum Geologists, Calgary, Special Publication No. 30, p. 121-137. _ _ . , Snowdon, L.R. and Stasiuk, L.D. 1989. Association of enhanced hydrocarbon generation and crustal structure in the Canadian Williston Basin. In: Current Research, Part D. Geological Survey of Canada, Paper 89-1 D, p. 35-47. and _ _ 1986. Speculation on the petroleum source rock potential of portions of the Lodgepole Formation (Mississippian), southern Saskatchewan. In: Current Research, Part B. Geological Survey of Canada, Paper 86-1 B, p. 647-651. Potter, D. and St. Onge, A. 1991. Minton pool, south-central Saskatchewan: a model for basement induced structural and stratigraphic relationships. In: Proceedings of the Sixth International Williston Basin Symposium, J.E. Christopher and E Haidl (eds.). Saskatchewan Geological Society, Special Publication No. 11, p. 21-33. Price, L.C., Ging, T., Daws, T., Love, A., Pawlewicz, M. and Anders, D. 1984. Organic metamorphism in the Mississippian- Devonian Bakken shale, North Dakota portion of the Williston Basin. In: Hydrocarbon Source Rocks of the Greater Rocky Mountain Region, J. Woodward, E E Meissner and J.L. Clayton (eds.). Denver: Rocky Mountain Association of Geologists, p.83-134. Rubinstein, I., Sieskind, O. and Alberecht, P. 1975. Rearranged sterenes in a shale: occurrence of simulated formation. Journal of the Chemical Society, Perkin Transactions I, p. 1833-1835. S a s k a t c h e w a n E n e r g y and M i n e s 1988. R e s e r v o i r A n n u a l 1987. Saskatchewan Energy and Mines, Petroleum and Natural Gas Branch, Miscellaneous Report 88-1. Schmoker, J.W., and Hester, T.C. 1983. Organic carbon in the Bakken Formation United States portion of Williston Basin; American Association of Petroleum Geologists, Bulletin, v. 67, no. 12, p. 2165-2174. Seifert, W.K.and Moldowan, J.M. 1981. Paleoreconstruction by biological markers. Geochimica et Cosmochimica Acta, v. 45, p. 783-794. _ _ , _ _ and Jones, R.W. 1980. Applications of biological marker chemistry to petroleum exploration; Paper SP 8. In." Proceedings of the Tenth World Petroleum Congress, v. 2, Heyden: Applied Science, p. 425438. Sieskind, O., Joly, G. and Alberecht, P. 1979. Simulation of the geochemical transformation of sterols: superacid effect of clay minera. Geochimica et Cosmochimica Acta, v. 43, p. 1675-1679. Snowdon, L.R. 1981. Organic geochemistry of the Upper Cretaceous/Tertiary d e l t a c o m p l e x e s of the B e a u f o r t M a c k e n z i e S e d i m e n t a r y Basin. Geological Survey of Canada, Bulletin 291.46p. and Osadetz, K.G. 1988a. Gasoline range (C5 to C8) data and Ci5+ Saturate Fraction Gas Chromatograms for the crude oils from southeastern Saskatchewan portion of the Williston Basin. Geological Survey of Canada, Open File Report 1785, 261p. _ _ and _ _ 1988b. Geological processes interpreted from gasoline range analyses of oils from southeast Saskatchewan and Manitoba. In: Current Research, Part D. Geological Survey of Canada, Paper 88-1D, p. 33-40. _ _ and Powell, T.G. 1979. Families of crude oils and condensates in the Beaufort-Mackenzie Basin. Bulletin of Canadian Petroleum Geology, v. 27, no. 2, p. 139-162. Stasiuk, L.D., Osadetz, K.G., Goodarzi, F. and Gentzis, T. (1991). Organic microfacies and basinal tectonic control on source rock accumulation; a microscopic approach with examples from an intracratonic and extensional basin. In: The Society for Organic Petrology, Proceedings of the Peter Hacquebard Symposium, Calgary, Sept. 10-12, 1990, W. Kalkrenth, R.M. Bustin and A.R. Cameron (eds.). Coal Geology. Recent Advances in Organic Petrology and Chemistry: A symposium honoring Dr. Peter Hacquebard. v. 19, p. 457-481. ___, _ _ and Potter, J. 1990. Fluorescence spectral analysis and hydrocarbon exploration: examples from Palaeozoic potential source rocks, Saskatchewan. In: Modern Exploration Techniques, L.S. Beck and C.T. Harper (eds.). Saskatchewan Geological Society, Special Publication No. 10, p. 242-251. and _ _ 1990. Progress in the life cycle and phyletic affinity of Gloeocapsomorpha prisca Zalessky 1917 from Ordovician rocks in Canadian Williston Basin. In: Current Research, Part D. Geological Survey of Canada, Paper 90-1 D, p. 127-137.
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OIL FAMILIES A N D T H E I R S O U R C E S IN C A N A D I A N W I L L I S T O N B A S I N
Thode, H.G. 1981. Sulphur isotope ratios in petroleum research and exploration: Williston Basin. American Association of Petroleum Geologists, Bulletin, v. 65, no. 9, p. 1527-1535. Thompson, K.F.M. 1983. Classification and thermal history of petroleum based on light hydrocarbons. Geochimica et Cosmochimica Acta, v. 47, no. 2, p. 303-316. van Graas, G.W. 1990. Biomarker maturity parameters for high maturities: calibration of the working range up to the oil/condensate threshold. In: A d v a n c e s in O r g a n i c G e o c h e m i s t r y 1989, Part lI, M o l e c u l a r Geochemistry, B. Durand and E Behar (eds.). Pergamon Press, London. Also issued as: Organic Geochemistry, v. 16, no. 4-6, p. 1025-1032. Waples, D.W., and Machihara, T. 1990. Application of sterane and triterpane biomarkers in petroleum exploration. Bulletin of Canadian Petroleum Geology, v. 38, p. 357-380. Wardlaw, N.E. and Reinson, G.E. 1971. Carbonate and evaporite deposition and diagenesis, Middle Devonian Winnipegosis and Prairie evaporite formations of south-central Saskatchewan. American Association of Petroleum Geologists,Bulletin, v. 55, p. 1759-1786. Webster, R.L. 1984. Petroleum source rocks and stratigraphy of the Bakken Formation in North Dakota. In: Hydrocarbon Source Rocks of the Greater Rocky Mountain Region, J. Woodward, F.F. Meissner and J.L. Clayton (eds.). Denver: Rocky Mountain Association of Geologists, p. 57-81. Williams, J.A. 1974. Characterization ofoil types in Williston Basin. American Association of Petroleum Geologists, Bulletin, v. 58, p. 124A153-1252. Zumberge, J.E. 1983. Tricyclic diterpane distributions in the correlation of Palaeozoic crude oils from the Williston Basin. ln: Advances in Organic Geochemistry 1981, John Wiley & Sons Ltd., p. 738-745. APPENDIX: EXPERIMENTAL Gasoline fractions (iC;nCs) were extracted (Snowdon and Powell, 1979) from whole crude oil and analyzed on a 60m DB-1 fused silica chromatogra-
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phy column using a flame ionization detector and Nelson Analytical integration system (Snowdon and Osadetz, 1988a, b). Whole crude oils were distilled and the > 210°C b.p. fraction was characterized. Gross compositions were determined using techniques similar to those discussed by Snowdon (1978). Saturate fractions were examined by capillary column gas chromatography, using a VARIAN 3700 gas chromatograph equipped with a 25 m fused-silica column coated with OV-1, temperature programmed from 50-280°C at a 4°C/min., using He as the carrier gas; and by capillary column gas chromatography-mass spectrometry (GC-MS), using either a KRATOS MS-80RF mass spectrometer controlled by a DS-55 data system or a VG 70SQ hybrid gas chromatograph-mass spectrometer-mass spectrometer (GC-MS-MS) in both GC-MS and GC-MS-MS mode. Samples reported here include both new discoveries and those reported in Osadetz et al. (1991) and Brooks et al. (1987), although differences in instrumentation and experimental conditions led to some changes in results. GC-MS conditions were typically: J & W 25 m DB5 column temperature programmed from 50-320°C at 4°C/rain. and coupled directly to the mass spectrometer source, operated with a 300 microA filament emission current and 70 eV ionization potential. Data were collected by either full mass spectral scanning or by multiple ion detection (MID), monitoring ions at m/z 177.1638, 191.1794, 217.1950, 218.2028, 231.2106, and 259.2262. GC-MS-MS experiments monitored numerous fragmentation pathways to check sterane and pentacyclic terpane compositions inferred from MID experiments, particularly the m/z 400.4000 to m/z 217.2000 transition to verify C29 sterane compositions when interference from other compounds was suspected. Source rocks were identified and characterized using RockEval/TOC anhydrous pyrolysis (Espitalie et al., 1985). Bituminous material was extracted using a Soxhlet apparatus (87:13 distilled Chloroform/Methanol mixture for 24 hr., following Snowdon, 1981). It was fractionated and saturate fractions were further characterized by SFGC and GC-MS methods similar to those described above for oils.
