The International Energy Agency on Thursday projected that Marcellus Shale gas production will increase 45 percent in the next six years as drillers produce more gas with fewer, more efficient rigs. The gas field is largely centered in Pennsylvania.

The Paris-based IEA, in a new report, said that the global natural-gas market is undergoing a major transformation driven by new U.S. shale-gas supplies, and that more than half the expected U.S. production will be used for liquefied natural gas for export.

Demand from China will drive much of the global growth, according to IEA. By 2022, the agency said that the United States "will be on course to challenge Australia and Qatar for global leadership among LNG exporters."