In this Oct. 14, 2011 file photo, a drilling rig is set up near a barn in Springville, Pa., to tap gas from the giant Marcellus Shale gas field.
In this Oct. 14, 2011 file photo, a drilling rig is set up near a barn in Springville, Pa., to tap gas from the giant Marcellus Shale gas field. (Associated Press)