Exploration potential of Birdbear (Nisku) Formation, north-central Montana
Recent discoveries of gas and oil in the Devonian Birdbear (Nisku) Formation on the east flank of the Sweetgrass arch have opened a new area for Devonian exploration. Devonian well control is sparse, but a regional surface, subsurface, and petrographic study has indicated good future potential for the discovery of significant Birdbear hydrocarbon reserves along a mappable trend. The Birdbear (Nisku) Formation ranges in thickness from 0 to 105 ft and is composed of dolomites with anhydrite and shale interbeds. Although binocular microscopic and petrographic data from 16 wells do not generally support an initial interpretation that Birdbear production is from dolomitized fossil-debris members, this interpretation is believed to be the most likely carbonate model for exploration. Selected isopach and structure maps were used to determine the location of paleotectonic features that were likely sites for Birdbear fossil-debris mounds. Although early success in exploration for Birdbear oil has resulted in small producing areas, exploration is at an early stage and larger accumulations are anticipated. Good potential exists for economic oil reserves at a shallow depth.
- Research Organization:
- FSR Associates, Englewood, CO
- OSTI ID:
- 6962642
- Report Number(s):
- CONF-8609129-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 70:8; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
Similar Records
Depositional and diagenetic models for Devonian Birdbear (Nisku) reservoirs, northeastern Montana
Nisku of northeastern Montana with special reference to Tule Creek area, Roosevelt County, Montana
Related Subjects
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Geology
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030200 -- Natural Gas-- Reserves
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ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
DEVONIAN PERIOD
DOLOMITE
EXPLORATION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERAL RESOURCES
MINERALS
MONTANA
NATURAL GAS DEPOSITS
NORTH AMERICA
OXYGEN COMPOUNDS
PALEOZOIC ERA
PETROGRAPHY
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SHALES
USA