Bill Powers has an article

Highlights.

"The two most important factors in the production profile of a play are its decline curve and its reserve life."

"I believe we are about to experience a big mismatch between US reserves and gas deliverability due in large part to long-lived shale gas reserves."

"Given that an increasing percentage of US reserves are in US shale plays which have very long reserve lives, we are headed for much lower production in the near future."

"Once an operator can prove that a shale formation is homogenous over a certain aerial extent through drilling, reservoir engineers are far more generous in their reserve bookings since they are more confident the EUR of each well will be similar."

"...[the] gas deliverability crisis is not widely recognized is that it is being overshadowed by the recent success of several unconventional gas plays. The biggest success story amongst the shale plays is the granddaddy of them all, the Barnett Shale."

"The final reason the coming supply crunch has evaded many is that the flurry of large shale play discoveries over the past two years has led many market observers to think that technology will make many more shale plays economic."