The U.S. Geological Survey (USGS) recently completed a geology-based assessment of the oil and gas resources of the Bakken and Three Forks Formations, located in North Dakota, Montana, and South Dakota, finding that these formations together hold an estimated mean of 7.38 billion barrels of oil, 6.7 trillion cubic feet (tcf) of gas, and 0.53 billion barrels of natural gas liquids. See USGS Fact Sheet 2013–3013: Assessment of Undiscovered Oil Resources in the Bakken and Three Forks Formations, Williston Basin Province, Montana, North Dakota, and South Dakota, 2013. The Three Forks Formation was found to have 3.73 billion barrels of estimated mean resource of oil, with the Bakken Formation having a 3.65 billion barrels (approximately the same amount as was found in the USGS’ 2008 assessment of the Bakken Formation). The formations combined estimate ranges from 4.42 million barrels with a 95% change of production to 11.43 billion barrels with a 5% chance. Gas estimates ranged from 3.43 tcf (with a 95% chance of production) to 11.25 tcf (with a 5% chance) and 0.23 billion barrels (95%) to 0.95 billion barrels (5%) of natural gas liquids. This assessment was undertaken as part of the USGS’ nationwide project to assess U.S. petroleum basins using standardized methodology and protocol. Data for this assessment was provided by the North Dakota Geological Survey, North Dakota Industrial Commission, Montana Board of Oil and Gas, and multiple industry groups working in the formations.

This article was prepared by Barclay Nicholson ( or 713 651 3662) from Fulbright’s Energy Practice Group.