Estimates of technically recoverable reserves in the United States vary as they are generated by geological inferences .
The U.S. Energy Information Administration 2009 estimate is 1747 trillion cubic feet , enough to provide domestic production at 2005 rates for nearly 80 years .
Estimates of technically recoverable reserves in the United States vary as they are generated by geological inferences , but the U.S. Energy Information Administration 2009 estimate is 1747 trillion cubic feet , enough to provide domestic production at 2005 rates for nearly 80 years .