Tracey J. Mercier Cheryl A. Woodall Geoffrey S. Ellis Thomas M. Finn Phuong A. Le Kristen R. Marra Heidi M. Leathers-Miller Ronald M. Drake II Christopher J. Schenk 2021 <p>Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean oil and gas resources of 134 million barrels of oil and 81 billion cubic feet of gas in upper Paleozoic strata of the Williston Basin Province in North Dakota, Montana, and South Dakota.</p> application/pdf 10.3133/fs20213023 en U.S. Geological Survey Assessment of undiscovered conventional oil and gas resources of upper Paleozoic strata in the Williston Basin Province, 2020 reports