Petroleum system model of the Devonian-Mississippian Bakken Formation in the Western Canada Sedimentary Basin, Saskatchewan and Alberta

Debra Higley-Feldman

The Devonian-Mississippian Bakken Formation, which correlates with the Exshaw Formation, is marginally mature for oil generation over most of its extent in the Williston Basin that lies in southern Alberta and Saskatchewan, part of the Western Canada Sedimentary Basin (WCSB). Thermal maturation ranges from immature for oil to overmature for gas generation in the Alberta Basin portion of the WCSB. Timing of oil and gas generation, migration, and accumulation were based on 1D and 4D petroleum system models that were calibrated to measured vitrinite reflectance and temperature data. Onset of oil generation from the Bakken in the Alberta Basin was about 65 million years ago (Ma) and peak generation was about 58 Ma, proximal to and under the Canadian Rocky Mountains; oil and gas migrated to the east and northeast across the basin. The Alberta Basin did not contribute oil or gas to the Williston Basin. Petroleum generation and migration was northward from the Williston Basin. Bakken, Exshaw, and Mississippian Banff Formations reservoirs are self-sourced, and areas of petroleum production range from marginally mature for oil generation to overmature for gas generation. More than 320 MMBO and 770 BCFG have been produced from these formations in the WCSB, of which more than 250 MMBO and 180 BCFG have been produced from the Williston Basin portion.

AAPG Search and Discovery Article #90156©2012 AAPG Rocky Mountain Section Meeting, Grand Junction, Colorado, 9-12 September 2012