Recently, the US Energy Information Administration has reported that around 3.8 billion bbl of proved reserves of crude oil and lease condensate had been increased to the exploration and production enterprises of oil and gas in the US in the year of 2011. The Energy Information Administration said that the proved reserves had been totally 39 billion bbl at the end of 2011, a 15% increase compared with last year. It is also the largest volume increase since 1977, when the Energy Information Administration began to publish proved reserves estimates.

In the meantime, the proved reserves of US wet natural gas increased to 348.8 tcf at the end of 2011 from the amount of 317.6 tcf at the end of 2010.

The Energy Information Administration was also alive to the largest areas of crude oil and lease condensate, where proved reserves of crude oil and lease condensate increased in 2011. They are Texas, the Gulf of Mexico federal offshore, Alaska, California, and North Dakota.

Among those five areas, Texas has the largest increase, totaled nearly 1.8 billion bbl, mostly from constant development in the Permian and Western gulf basins. North Dakota had the second-largest increase, nearly 771 million bbl, along with the promotion of development activity in the Williston basin. The combination of North Dakota and Texas totted up composed of two thirds of the net increase in the proved oil reserves totally in 2011.

In addition, Texas, Wyoming, Louisiana, Oklahoma, and Pennsylvania were the five largest gas producing states of proved wet natural gas reserves increased in 2011, according to the Energy Information Administration. The producing increase of Texas and Pennsylvania resulted in a combined 73% net increase in proved wet natural gas reserves in 2011.

(Edited by Jeasin)