Trenton/Black River Oil and Gas Reservoirs in Michigan

Harrison III, William B.
Michigan Basin Core Research Lab, Department of Geosciences, Western Michigan University, Kalamazoo, MI

The Trenton/Black River Formations contain the largest oil fields in the Michigan Basin. Most notable of these are the Indiana-Lima trend at about 500 million barrels and the Albion-Scipio Field at about 130 million barrels. These reservoirs are stratigraphic or combination traps of dolomite in regional tight limestone. Within Michigan, the Trenton/Black River fields typically possess a linear, narrow field geometry. Current models suggest that faults and fractures of many scales control field occurrence and reservoir quality. Recent examination of cores from Albion Scipio fields do show some significant fracturing, but much of the reservoir, although dolomitized, shows little or no fracturing. Original facies characteristics template the dolomitization and control variations in reservoir quality in the field. Reservoir models for these types of fields should include variations in original facies characteristics as well as fracturing trends and patterns.

Facies identified in core include deposits formed in several open shelf to shallow subtidal environments. Skeletal and pelletal wackestone to packstone lithologies dominate the stratigraphic section in Albion Scipio field. A distinctive interval in the Black River Formation shows fenestral wackestones with significant porosity. Mapping of vertical stacking patterns of these various facies would contribute significantly to a better understanding of the complete reservoir architecture in the Albion Scipio field.

AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004