North Texas' Barnett shale is the granddaddy of modern shale plays. During the past decade, activity has exploded to encompass all or parts of 20 counties. Today, more than 12,000 Barnett shale wells produce 5 billion cubic feet of gas per day, and nearly three-fourths of these wells are horizontal. Success has been so robust that Barnett gas is now approaching 10% of U.S. domestic supply.

Despite the intensive drilling programs of the past several years, great volumes of gas still remain to be extracted from the Barnett reservoir. Efforts in this leading shale play have shifted to controlling costs and improving recovery of in-place gas.