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The AAPG/Datapages Combined Publications Database
AAPG Bulletin
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Thirty-five oil fields have been developed in the Mission Canyon Formation in northern Bottineau and Renville Counties, North Dakota. Six cyclic sedimentary units have been defined in the Mission Canyon in that area. They are, in ascending intervals: Landa, Wayne, Glenburn, Mohall, Sherwood, and Bluell. These intervals or sequences were deposited during marine regressions in the intracratonic Williston basin. A brief but widespread transgression at the initiation of each cycle resulted in deposition of a thin argillaceous marker which can be correlated over large areas.
The depositional setting during Mission Canyon time was similar to that of shallow epeiric seas. Limited circulation resulted in hypersaline conditions and widespread evaporite deposition. A shelf-to-basin configuration probably never existed; rather, deposition occurred on a shallow ramp with little topographic relief. Exposure and the resultant vadose leaching caused occurrence of porosity on depositional highs such as oolite shoals and organic banks. Anhydrite plugging of this porosity is common where evaporite environments migrated basinward over the porous facies.
Three types of stratigraphic traps have been recognized, these are: (1) a carbonate-evaporite facies change where porous carbonates are sealed by the overlying evaporite facies; (2) porous carbonates sealed by nonporous carbonates; (3) porous carbonates subcrop beneath the Triassic Spearfish shale which serves as the updip seal. An understanding of the distribution of porous facies is essential to determining areas of future exploration.
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