Geology and natural gas occurrence, western Williston Basin

Journal Article · Mon Jan 01 00:00:00 EST 1968 · Mem. - Am. Assoc. Pet. Geol.; (United States)

OSTI ID:5691577

McCrae, R O; Swenson, R E

The W. Williston Basin has produced gas since a 1913 discovery at Cedar Creek anticline, but during the past decade nearly all the gas found has been in solution in oil. In a sedimentary rock section averaging 10,000 ft in thickness, about one-third of the material, in approx. the lower half of the section, consists of carbonate and evaporites. The rest of the beds are principally sandstone and shale of shallow-marine deposition. All commercial gas in Paleozoic rocks is in solution in oil. Small gas reserves have been found in fractured siltstones of the Cretaceous Colorado shale at Hardin, and in the Shannon sandstone at Pumpkin Creek. Most of the gas in the W. Williston Basin is in nonassociated accumulations in and adjacent to the Cretaceous Judith River and Eagle formations. The trapping is related partly to folding, but also is at the extreme seaward limits of sandstone tongues. Porosity of less than 10% and low permeability values are characteristic of the reservoirs and fracturing is regarded as important in improving overall permeability of the reservoirs. At Cedar Creek anticline, 6 million cu ft a day of 90% nitrogen gas was treated in a Cambrian sandstone.

• Research Organization: Standard Oil Co California; Chevron Oil Co
• OSTI ID: 5691577
• Journal Information: Mem. - Am. Assoc. Pet. Geol.; (United States), Vol. 2:9
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
NATURAL GAS DEPOSITS
GEOLOGY
NORTH DAKOTA
ANTICLINES
CAMBRIAN PERIOD
CRETACEOUS PERIOD
GEOLOGIC TRAPS
PALEOZOIC ERA
RESERVES
SEDIMENTARY ROCKS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
MESOZOIC ERA
MINERAL RESOURCES
NORTH AMERICA
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ROCKS
ROCKY MOUNTAIN REGION
USA
030200* - Natural Gas- Reserves
Geology
& Exploration