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Regional stratigraphy and general petroleum geology, Williston Basin

Conference · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:6271202

Paleozoic sedimentary rocks in the Northern Great Plains and northern Rocky Mountain region include a sequence of dominantly shallow-water marine carbonate, clastic, and evaporite deposits of Middle Cambrian through Early Permian age. The lower part of the Paleozoic section is a sequence of marine sandstone, shale, and minor limestone, rangeing in age from Middle Cambrian through Middle Ordovician. Some porous sandstone beds occur in this section, mainly in the eastern and southern bordering areas of the Williston basin and Central Montana trough. Upper Ordovician through middle Upper Mississippian rocks are primarily carbonate beds, which contain numerous widespread cyclic interbeds of evaporite and fine-grained clastic deposits. Carbonate mounds or banks were deposited through most of this time in the shallow-water areas of the Williston basin and northern Rocky Mountains. Porous units, mainly dolomite or dolomitic limestone, are common but discontinuous in most of this sequence, and are more widespread in the eastern and southern margins of the Williston basin. Cumulative petroleum production (January 1982) in the United States part of the Williston basin was about 1.1 billion bbl of oil and 1.6 tcf gas. Estimated remaining recoverable reserves are about 400 million bbl of oil and 0.8 tcf gas. U.S. Geological Survey 1980 estimates of undiscovered recoverable oil and gas resources are about 900 million bbl of oil and 3.5 tcf gas.

Research Organization:
Geological Survey, Missoula, MT
OSTI ID:
6271202
Report Number(s):
CONF-8506201-
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 69:5; ISSN AAPGB
Country of Publication:
United States
Language:
English