Stratigraphy and Petroleum Potential of the Bakken - Three Forks Petroleum System: Northeastern Montana

Franklin, Alyssa L.; Sonnenberg, Stephen

The Three Forks Formation of the Williston Basin is a tight oil reservoir beneath the organic-rich Lower Bakken Shale. Currently there is limited understanding of the depositional controls of the formation as well as its reservoir potential outside of North Dakota. This study applies core analysis and well log correlation to understand the depositional lithofacies and sequence stratigraphic framework of the formation, which is used to evaluate the play potential in Northeast Montana. Core studies show that the Three Forks Formation was deposited in a broad, low gradient peri-tidal environment which allowed for the deposition of laterally extensive facies. These peri-tidal facies represent an arid to semi-arid climate in which it was not uncommon to have storms. Relative sea level fluctuations can be observed at a high frequency throughout the formation. The larger scale stratigraphic changes help to explain reservoir facies deposition.

Petroleum system components including reservoir quality based on core analysis, source maturity, and trapping and/or seal mechanisms have been analyzed in Northeastern Montana. Where favorable characteristics are present, the Three Forks Formation has significant potential as an emerging tight oil play.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013