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Kirk Osadetz1,
Mark Obermajer2,
Maowen Li3,
Lloyd Snowdon2,
Martin Fowler1,
William Hansen4,
Julie LeFever5,
Paul Diehl6,
Randolph Burke6,
Kipp Carroll7,
Marv Rygh8,
Mac Clark9
(1) Geological Survey of Canda - Calgary, Calgary, AB
(2) Geological Survey of Canada - Calgary, Calgary, AB
(3) Geological Survey of Canada, Calgary, AB
(4) Jireh Consulting, Great Falls, MT
(5) North Dakota Geological Survey, Grand Forks, ND
(6) North Dakota Geological Survey, Bismarck, ND
(7) Carroll Petroleum, Billings, MT
(8) Fidelity E&P, Bismarck, ND
(9) Beartooth Oil and Gas, Billings, MT
Abstract: Oils in United States portions of Williston Basin
Oils in Canada are divided into compositional families using biological markers with sources originating in: a stratigraphic interval, a facies, or a mixture of source rocks. Major Canadian families, with sources in Ordovician Bighorn Gp., Devonian Elk Point, Saskatchewan and Manitoba gp.’s, Devonian-Carboniferous Bakken Fm., and Carboniferous Lodgepole Fm. extend into the US, where previous work showed additional families and sources. A family in Middle Cambrian to Upper Devonian reservoirs, which resembles Canadian oils from the Middle Devonian succession has a distinctive carbon isotopic composition. No source has been identified for these oils, but they may originate in the Middle Cambrian to Lower Ordovician succession. Samples from Lower Carboniferous Madison Gp. reservoirs suggest a greater mixing of oils from Bakken and Lodgepole sources, than do Canadian pools. Other oils predominantly from the upper Carboniferous succession show a wider compositional range than previously reported, suggesting that a number of source rocks are effective in that interval. The reconsideration of oil-oil and oil-source correlations point to new exploration opportunities, particularly in the deeper basin, due to the complicated migration patterns.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana