In the early years of this century, U.S. pundits were showing charts and graphs indicating that the natural gas supplies coming from the Gulf of Mexico were in decline and the situation showed no signs of improving. But a quiet revolution already was taking place.

George Mitchell of Mitchell Energy, who had been laboring in the Barnett Shale for several years with little success, finally found the right recipe of horizontal drilling and hydraulic fracturing. And it was off to the races. Other shales followed: the Haynesville, Fayetteville, Marcellus, Utica, Eagle Ford, Bakken, etc. The country’s vast accumulation of shales, which had always been studiously avoided by drillers in the past, were suddenly being viewed as its salvation. When gas prices dropped due to oversupply, operators went after oil, ultimately leading to one of the industry’s most prolonged downturns.

In these pages you’ll find an interview with Steve Holditch, whom E&P interviewed 15 years ago when unconventional resources were still a glimmer on the horizon. Holditch looks back over those remarkable 15 years and postulates what might be next. We also take a look at some of the latest technological breakthroughs that help operators drill, complete and produce more efficiently in this low-price environment.

Read E&P's November cover stories:

Shales: a look back

US shale operators focus on completion optimization, best practices

MPD emerging as preferred drilling method in Utica Shale

Composite vs. dissolvable fracture plugs

Automated pigging prevents corrosion

Frack plug stacks up against competition