Bakken and Three Forks Petroleum Development, Production and Potential, Western Williston Basin, Northeastern Montana

Stephen Sonnenberg and Alyssa Franklin

The Bakken and Three Forks formations are productive and potentially productive in northeast Montana, respectively. The Bakken is an established producer with production from horizontal wells commencing in 2000 with the development of Elm Coulee. The area north of Elm Coulee is currently being exploited by horizontal wells in the Bakken. This area also has the first Three Forks wells. Much of the production and completion information is in a confidential status. The Middle Bakken facies are nearly identical to Bakken facies observed in North Dakota. Six or more distinct facies are present. Overall the succession appears to represent shelf deposits ranging from subtidal to lower intertidal back to subtidal. The amount of limestone, dolomite and sandstone present varies across the area. In general, more dolomite is present to the south in the Elm Coulee area and sandstone content increases to the north. The Three Forks consists largely of silty dolostone, clay-rich dolostones, red beds and anhydrites. These units were deposited in subtidal to supratidal environments. Four regional units of the Three Forks have been identified and regional thicknesses and correlations established. The upper two cycles of the Three Forks are the current target of exploration in NE Montana. Recent cores of these intervals show significant residual oil saturation. Thus, petroleum potential in these units is high. Structural elements in NE Montana include the Brockton-Froid fault zone and the Poplar anticline. These structures are important controls on Bakken and Three Forks production.

AAPG Search and Discovery Article #90156©2012 AAPG Rocky Mountain Section Meeting, Grand Junction, Colorado, 9-12 September 2012