“U.S. crude oil proved reserves rose for the fourth consecutive year in 2012, increasing by 15% to 33 billion barrels, according to the U.S. Crude Oil and Natural Gas Proved Reserves (2012) report released April 10 by the U.S. Energy Information Administration. U.S. crude oil and lease condensate proved reserves were the highest since 1976, and the 2012 increase of 4.5 billion barrels was the largest annual increase since 1970, when 10 billion barrels of Alaskan crude oil were added to U.S. proved reserves. Contributing factors to higher crude oil reserves include increased exploration for liquid hydrocarbons, improved technology for developing tight oil plays, and sustained high historical crude oil prices. Proved reserves are volumes of oil that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions. Tight oil plays, which contain conventional oil in reservoirs of low permeability that is accessed through advanced drilling techniques, accounted for 7.3 billion barrels (22% of the U.S. total) of proved reserves of crude oil and lease condensate in 2012. Texas recorded the largest volumetric increase (3.0 billion barrels) in proved oil reserves among individual states, largely because of development in the Permian and Western Gulf basins, while North Dakota had the second-largest increase (1.1 billion barrels), driven by development of the Bakken and Three Forks formations in the Williston Basin.”