Using a geology-based assessment method, the U.S. Geological Survey estimated means of 16.6 trillion cubic feet of undiscovered natural gas, 639 million barrels of undiscovered oil, and 131 million barrels of natural gas liquids in the Powder River Basin Province.

For Further Information
Supporting geologic studies and reports on the assessment method used in the Powder River Basin Province assessments
of conventional resources are in preparation (2006). Assessment results are available at the USGS Central Energy Team website, http://energy.cr.usgs.gov/oilgas/noga.