U.S. proved reserves of oil increase for the fifth year in a row in 2013; U.S. natural gas proved reserves increase 10% and are now at an all-time high

• North Dakota proved oil reserves surpass the Gulf of Mexico
• Pennsylvania and West Virginia account for 70% of increase in natural gas reserves

U.S. crude oil proved reserves increased for the fifth year in a row in 2013, a net addition of 3.1 billion barrels of proved oil reserves (a 9% increase) according to U.S. Crude Oil and Natural Gas Proved Reserves, 2013, released today by the U.S. Energy Information Administration (EIA).
U.S. natural gas proved reserves increased 10% in 2013, more than replacing the 7% decline in proved reserves seen in 2012, and raising the U.S. total to a record level of 354 trillion cubic feet (Tcf).

At the state level, North Dakota led in additions of oil reserves (adding almost 2 billion barrels of proved oil reserves in 2013, a 51% increase from 2012) because of development of the Bakken and Three Forks formations in the Williston Basin. North Dakota's proved oil reserves surpassed those of the federal offshore Gulf of Mexico for the first time in 2013. Texas (still the state with the largest proved reserves of oil) had the second largest increase, adding 903 million barrels of proved oil reserves in 2013.

Pennsylvania and West Virginia reported the largest net increases in natural gas proved reserves in 2013, driven by continued development of the Marcellus Shale play, the largest U.S. shale gas play based on proved reserves. Combined, these two states added 21.8 Tcf of natural gas proved reserves in 2013 (13.5 Tcf in Pennsylvania and 8.3 Tcf in West Virginia) and were 70% of the net increase in proved natural gas reserves in 2013. U.S. production of both oil and natural gas increased in 2013: Production of crude oil and lease condensate increased 15% (rising from 6.5 to 7.4 million barrels per day), while U.S. production of natural gas increased 2% (rising from 71 to 73 billion cubic feet per day).

Proved reserves are those volumes of oil and natural gas that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions. An increase in natural gas prices used to characterize existing economic conditions contributed to the reported increase in proved natural gas reserves. For example, the 12-month first-of-the-month average natural spot price at Henry Hub increased from $2.75 per million Btu (MMBtu) in 2012 to $3.66 per MMBtu in 2013.

EIA's estimates of proved reserves are based on an annual survey of domestic oil and gas well operators.
U.S. Crude Oil and Natural Gas Proved Reserves, 2013 is available at: http://www.eia.gov/naturalgas/crudeoilnaturalgasreserves.