Rising oil prices, shale exploration accelerate US reserves growth

In November 2010, the US Energy Information Administration released its estimates for US oil and natural gas reserves for 2009. Comparing year-end 2009 to 2008 values, proved crude oil plus condensate reserves rose 8.6% to 22.3 billion bbl, the largest increase in over three decades. Dry gas reserves increased 11.4% to 272.5 Tcf, continuing the trend of the last several years. New reservoir discoveries, largely in existing fields or extensions of existing fields, drove much of the growth for both oil and gas. This exploration is mostly taking place onshore the Lower 48 states, particularly in unconventional resource plays.

US crude oil plus lease condensate proved reserves, reserves changes and production, 2009, million bbl

Crude and condensate. Proved reserves increased by 100 million bbl or more in California, North Dakota, Texas, Utah and the federal Gulf of Mexico in 2009. Texas had the largest increase of 529 million bbl, primarily in the Permian Basin. North Dakota recorded the second-highest increase, 481 million bbl, due to Bakken Shale development. Both of these increases can be attributed to recovering crude oil prices after the 2008 crash.

US dry natural gas proved reserves, reserve changes and production, 2009, Bcf at 14.73 psia and 60°F

Natural gas. The increase in natural gas reserves is the direct result of significant shale gas development in Louisiana, Arkansas, Texas, Oklahoma and Pennsylvania. These reserve additions occurred despite stagnating natural gas prices and a fourth consecutive year of increased wet gas production, suggesting operators were drilling to hold acreage and applying more efficient horizontal drilling and multistage fracing technologies.

Not shown are natural gas liquids, which saw a 9% increase in proved reserves to 7.8 billion bbl. Texas had the largest NGL reserve increase in 2009, followed by Wyoming and Oklahoma.