U.S. Crude Oil and Natural Gas Proved Reserves

"U.S. crude oil and lease condensate proved reserves increased year-over-year by 4.5 billion barrels (15.4%) because of a large volume of extensions to existing fields (5.2 billion barrels) particularly in Texas and North Dakota.

• U.S. wet natural gas proved reserves decreased 26 trillion cubic feet (7.5%) in 2012. Low natural gas prices, reflected in a 34% decline in the 12-month, first-of-the-month, average spot price of natural gas at the Henry Hub between 2011 and 2012, led to large negative net revisions (-45.6 trillion cubic feet) to the reserves of existing fields that offset almost all gains from extensions of existing fields.
  Crude oil reserves