The U.S. Energy Department's Energy Information Administration reports that proven oil reserves in the United States increased 13 percent in 2010 to 25.2 billion barrels. Proven natural gas reserves passed 300 trillion cubic feet for the first time in U.S. history in 2010 to reach 317.6 tcf.
EIA Administrator Adam Sieminski said there is a great potential for significant gains in U.S. oil and natural gas production.
"The use of horizontal drilling and hydraulic fracturing in shale and other tight rock formations played an important role in the increase of oil and natural gas reserves," he said in a statement.
The EIA, in a report, said Texas led the country in natural gas gains because of developments in the Barnett and Haynesville-Bossier shale formation. Louisiana was close behind with its Haynesville play while Pennsylvania saw gains from the Marcellus shale formation.
Hydraulic fracturing is a controversial practice. Chemicals used in the process, known also as fracking, are considered harmful should they seep into groundwater.