Heterogeneously

The Bakken Shale and Three Forks formation in the Williston Basin in Montana, North Dakota and South Dakota contain a combined estimated 7.4 billion bbl of undiscovered, technically recoverable oil, 6.7 Tcf of undiscovered, technically recoverable natural gas and 530 million bbl of undiscovered, technically recoverable natural gas liquids (NGL), according to an assessment released Tuesday by the United States Geological Survey (USGS).