ABSTRACT: Exploration Opportunities in the Glenburn, Sherwood, and Rival Members of the Upper Mission Canyon Formation Along the Northeast Flank of the Williston Basin

HENDRICKS, MICHAEL L., Hendricks and Associates, Inc., Denver, CO, and JACOB D. EISEL, E-M Resources Inc., Denver, CO

The upper Mission Canyon Formation along the east flank of the Williston basin is a seaward-stepping sequence of carbonate and evaporite beds deposited along paleoshorelines and in nearshore shoals. Wireline log markers are used to informally subdivide the Mission Canyon into members based on progradational cycles. The most prolific oil reservoirs in the Mission Canyon occur in the Glenburn, Sherwood, and Rival members. Production in these members occurs along paleoshorelines and in offshore shoals.

Shoreline oil reservoirs are principally oolitic limestones and are trapped updip by impermeable dolomudstone and anhydrite.

Shoreline fields occur within anhydrite embayments produced by the basinward progradation of sabkhas across tilted half-grabens. Within a given embayment, reservoir quality and trap configuration were controlled by the relative slope of the shelf. The degree of shelf steepness controlled depositional energy and the development of porous grainstones.

Oolitic shoals were deposited basinward of shorelines and porosity developed in upper intertidal environments. Intershoal skeletal mudstones and wackestones are updip trap facies. Slope-breaks across the shelf also controlled the position of island-shoal reservoirs and traps.

Glenburn and Rival shoreline trends have not been adequately evaluated. The Glenburn shoreline trend offers both conventional trap configurations and enhancement by dissolution of the Devonian Prairie Evaporite Salt. Dissolution of the Prairie is part of the trapping mechanism at Glenburn field. Salt dissolution extends many miles south of Glenburn field, yet there are only sparse tests along this trend.

Shoal reservoirs have not been adequately evaluated in Glenburn, Sherwood, and Rival offshore trends. Production at Smith field from Sherwood beds indicates that these trends are economic.

AAPG Search and Discovery Article #91017©1992 AAPG Rocky Mountain Section Meeting, Casper, Wyoming, September 13-16, 1992 (2009)