Using a geology-based assessment methodology, the U.S. Geological Survey–Afghanistan Ministry of Mines and Industry Joint Oil and Gas Resource Assessment Team estimated mean volumes of undiscovered petroleum in northern Afghanistan; the resulting estimates are 1,596 million barrels of crude oil, 15,687 billion cubic feet of natural gas, and 562 million barrels of natural gas liquids. Most of the undiscovered crude oil is in the Afghan-Tajik Basin, and most of the undiscovered natural gas is in the Amu Darya Basin.