Dobson Butte Field, Williston Basin, Stark County, North Dakota: Nontypical Oil Production

Willard J. Guy

The Dobson Butte field (T139N, R96W), Stark County, North Dakota, was discovered in 1982 following a detailed seismic program. Production is primarily from a structural trap in the Interlake Formation of Silurian age. Three oil wells are presently producing from a dolomite reservoir at about 11,000 ft in depth. Primary recoverable reserves of these three producing wells is calculated to be about 2 million bbl of oil. Additional reserves will come from further development of the Interlake reservoir as well as from the deeper Red River (Ordovician) Formation.

The Dobson Butte field is a nontypical oil field within the Williston basin as to its high pour point oil (90°F), high production water cuts (85-95%), lack of good oil shows in samples, unpredictable noncontinuous oil-producing reservoirs throughout the entire 600-ft Interlake Formation, difficulty in log interpretations, and difficulty in determining the source bed.

The interpretation of these nontypical characteristics of Interlake oil production in the Dobson Butte field compared to other Interlake oil production within the Williston basin will have a profound effect upon future Interlake exploration.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.