The early days of the shale boom were driven by a mad hunt for the next big resource that could be developed with emerging technologies. But after the land grab, operators have turned to developing their leases and finding the best way to get wells to flow. That requires expertise and innovation.

"You don't get paid today to find new reserves, you get paid to get the existing reserves out of the ground," said Tony Weber, chief operating officer of Natural Gas Partners, one of the original private equity players in the unconventional sector.