2014 Rocky Mountain Section AAPG Annual Meeting

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Petroleum System Model of the Mississippian Bakken Formation in the Northern Williston Basin, Saskatchewan, Southwestern Manitoba, and Southeastern Alberta


More than 400 million barrels of oil, 380 trillion cubic feet of gas, 6,000 barrels of condensate, and 2 billion barrels of water have been produced from about 7,700 wells in the Bakken and underlying Big Valley and Torquay Formations of the Devonian-Mississippian Three Forks Group in the Canadian portion of the Williston Basin. These totals include some commingled production from the overlying Lower Mississippian Banff and Lodgepole Formations. Although the Bakken production is from conventional pools, approximately half of the well completions are horizontal. Bakken source strata are immature for oil generation over almost their entirety within the northern Williston Basin in Saskatchewan, southwestern Manitoba, and southeastern Alberta. There is potential for self-sourced oil proximal to and north of the North Dakota border with Saskatchewan. Timing and distribution of oil generation, saturation, migration, and accumulation are based on 4D petroleum system models that were calibrated to vitrinite reflectance, temperature, and drillstem test pressure data. Petroleum generation and migration was radially northward from the Williston Basin, starting as much as 90 million years ago (Ma), with peak generation at about 65 Ma. The Alberta Basin may have contributed petroleum along the axis of the Sweetgrass Arch, which forms a hydrologic and petroleum system divide between the basins. Onset of oil generation from the Bakken equivalent in the Alberta Basin was about 65 Ma and peak generation was about 58 Ma, proximal to and under the Canadian Rocky Mountains.