Satellite Linear Features and Pressure Variations in Cretaceous Shallow Gas Reservoirs, Southern Bowdoin Dome, Montana

SHURR, GEORGE W., St. Cloud State University, St. Cloud, MN, FREDERICK D. WOSICK, Williston Basin Interstate Pipeline Company, Bismarck, ND, and MARY K. TOZER and ALLAN D. TWEED, St. Cloud State University, St. Cloud, MN

For three decades prior to 1960, shallow gas was produced in the southern part of Bowdoin dome from the Cretaceous Bowdoin Sandstone of the Carlile Formation and the Phillips Sandstone of the Greenhorn Formation. Historical production records from this period suggest that patterns of pressure decline are closely related to the geometry of linear features visible on satellite images. Linear features mapped at a scale of 1:1,000,000 on multispectral scanner Landsat images correspond with geomorphic elements of the Milk River, Beaver Creek, and White Water Creek drainage systems. Regional lineament zones interpreted from linear features are believed to outline basement blocks which controlled deposition and deformation on Bowdoin Dome and in other areas of the northern Great Plains.

Initial formation pressures on southern Bowdoin dome are lower in a zone marked by northwest linear features, and subsequent pressure declines through several decades show areas of greatest change are bounded by linear features. A series of pressure maps illustrate isobars elongated along the northwest trend and shifting to the northwest as production continues. In the western part of the field, isobars also parallel a northeast-trending linear feature. Correspondence of isobar patterns and linear features may be related to increased fracture porosity and permeability along a basement block boundary, or it may be influenced by other geologic features related to block geometry such as depth of burial or reservoir distribution.

AAPG Search and Discovery Article #91010©1991 AAPG Rocky Mountain Section Meeting, Billings, Montana, July 28-31, 1991 (2009)