The Appalachian Basin now produces about 2.5 billion cubic feet of gas per day, but that number is set to rise dramatically in the future as more Marcellus shale wells are drilled in Pennsylvania, speakers said at Hart Energy's Marcellus Midstream Conference in Pittsburgh this week.

Some 2,300 shale wells have been drilled so far in Pennsylvania, according to officials, and the estimated resource, as much as 260 trillion cubic feet of recoverable gas, could make the play the second-largest gas field in the world after fields in Qatar.

Midstream ...