SHREVEPORT, La. — The Haynesville Shale in northwestern Louisiana has become the largest-producing natural gas shale find in the United States, surpassing the Barnett Shale in Texas, a federal agency said Friday.

The U.S. Energy Information Administration said the Louisiana find, which experts say could have up to 39 trillion cubic feet of natural gas, overtook Barnett's volumes by mid-February even after the Texas site recovered from freezing weather. Gas wells are sometimes shut down during freezing weather to avoid blockage from ice.

The EIA said Haynesville is currently producing about 5.5 billion cubic feet of gas daily, exceeding the Barnett production of about 5.25 billion cubic feet.

According to the Louisiana Department of Natural Resources, the state has issued permits for about 2,000 wells in Haynesville and more than 1,000 have gone into production since mid-2008. The agency said 500 more wells are near completion and 121 are currently being drilled.

Louisiana's natural gas production exceeded 2 trillion cubic feet last year for the first time since 1982, DNR said.

The EIA said drillers and producers in Haynesville have been able to take advantage of what has been learned while developing Barnett. For example, nearly a decade was needed to reach production of 5 billion cubic feet a day in Texas. The same level was reached in less than three years in northwestern Louisiana, EIA said.

"Technology-driven efficiency gains have enabled the Haynesville producers to reach that level with far fewer wells," EIA said.

EIA also said that major expansions to the gas transmission system have been developed in northwestern Louisiana.

Drilling has been slowing in the Barnett as explorers turn their attention to $100-per-barrel oil, the report said.

However, industry analysts say drilling will probably slow in Haynesville, as well, if oil prices remain high and gas prices remain low.

DNR Secretary Scott Angelle called on the federal government to make more use of domestic natural gas, including its use as a motor fuel.