Petroleum geology, Sweetgrass Arch, Alberta

Journal Article · Thu Mar 01 04:00:00 EST 1973 · Earth Sci. Bull.; (United States)

OSTI ID:5269885

Herbaly, E L

The Sweetgrass Arch is a positive structural feature extending from central Montana into SE. Alberta. Rock units ranging in age from Precambrian Beltian to Upper Cretaceous Montanan are exposed along the 350-mile axis. Early exploration for hydrocarbons was naturally focused on the search for structural traps because such a large positive trend would be expected to have many faulted and domal anomalies. Active development work over the years proved that the stratigraphic trap predominated as the setting for hydrocarbon accumulation. Even the large, closed structural anomaly of the Kevin-Sunburst Dome does not entirely cause the entrapment of oil and gas there, but irregular porosity development in Mississippian carbonates and lensing and pinchout of Cretaceous sandstones more accurately accounts for the accumulation found to date. Large gas reserves are found in thin blanket sandstones of Upper Cretaceous age, principally in the Medicine Hat and Second White Specks zones. Minor gas deposits also are found in the Lower Cretaceous Bow Is. Formation in long, narrow sand bars. A 300-ft thick interval of silty and sandy shale in the Milk River Formation has been known to contain gas for some time, but only recently has this enormous deposit been developed. (10 refs.)

• OSTI ID: 5269885
• Journal Information: Earth Sci. Bull.; (United States), Journal Name: Earth Sci. Bull.; (United States) Vol. 6:1; ISSN ESCBA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
ALBERTA
CANADA
EXPLORATION
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
GEOLOGY
HYDROCARBONS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
ORGANIC COMPOUNDS
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
POROSITY
RESOURCES
STRATIGRAPHY