ABSTRACT: Smith Field, Renville County, North Dakota: Refining an Exploration Model

Jacob D. Eisel, Michael L. Hendricks

Smith field produces from the Sherwood and Bluell beds of the Mission Canyon formation (Mississippian). Extensive coring within the field provided an opportunity to refine currently accepted exploration models.

The Sherwood limestone reservoir in the field is characterized by high rates of oil production from peloidal, oolitic, and pisolitic grainstones. These carbonate grains were deposited in intertidal environments associated with island-shoal buildups. The Sherwood trap at Smith is an updip facies change to impermeable mudstones and wackestones that were deposited in subtidal (intershoal) environments.

The Bluell beds were deposited in a barrier-lagoon complex. Productive Bluell beds are peloidal, oolitic, and pisolitic grainstones that were part of a low relief barrier-shoal complex. The Bluell trap is a facies change to "tight" grainstones and skeletal mudstones and wackestones. The grainstones are storm-generated washover deposits. Lagoonal mudstones and wackestones contain small ostracods and gastropods typically found in low-energy restricted environments.

Depositional modeling from Bluell and Sherwood cores provides greater accuracy in facies mapping and prediction. This will likely lead to further discoveries along Sherwood and Bluell shoreline trends.

AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990