Review of geology and petroleum potential of north-central Montana

Conference · Fri Jul 01 04:00:00 EDT 1988 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6179766

Dyman, T S; Maughan, E K

An assessment of undiscovered petroleum resources of the north-central Montana petroleum province was conducted using a play analysis approach for the Federal Lands Assessment Program. More than 340 million bbl of oil and 1175 bcf of gas have been produced from the 33 major fields in the province since 1919 when Cat Creek field was discovered in Petroleum County. Late Precambrian through Tertiary strata can be grouped into four major exploration plays: upper Proterozoic-lower Paleozoic oil play, Devonian-Mississippian oil and gas play, Jurassic-Lower Cretaceous oil and gas play, and Upper Cretaceous gas play, Jurassic-Lower Cretaceous oil and gas play, and Upper Cretaceous gas play. A fifth play, the Pennsylvanian oil play, is not significant because Pennsylvanian rocks are absent, except in the extreme southern part of the region where only minor amounts of oil have been produced in this province. Organic, carbon-rich hydrocarbon source rocks are thermally immature to mature. Most Upper Cretaceous gas is biogenic methane from thermally immature source rocks. Many Laramide structures enhance petroleum traps within the province. Even where structural closure exists, as on the crest of the sweet-grass arch, most reservoirs are partly controlled by facies changes in reservoir rocks. Paleozoic carbonate reservoirs include evaporite-carbonate cycles, bioclastic carbonate banks, and paleokarst systems that have been enhanced by dolomitization. Clastic reservoirs include marine and nonmarine sandstones with lateral and vertical facies variations. Since 1915, more than 15,000 wells have been drilled in the province; total footage drilled is more than 26 million ft, of which approximately 11 million ft are from exploratory wells. The total ultimate recoverable oil assessment approximates 370 million bbl, of which 13 million bbl are in fields smaller than 1 million BOE.

• Research Organization: Geological Survey, Denver, CO (USA)
• OSTI ID: 6179766
• Report Number(s): CONF-8808223-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 72:7
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CARBONATE ROCKS
CRETACEOUS PERIOD
DEVONIAN PERIOD
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC TRAPS
GEOLOGY
JURASSIC PERIOD
MESOZOIC ERA
MINERAL RESOURCES
MISSISSIPPIAN PERIOD
MONTANA
NATURAL GAS DEPOSITS
NORTH AMERICA
PALEOZOIC ERA
PENNSYLVANIAN PERIOD
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
RESOURCE POTENTIAL
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
USA