In the race to acquire positions in unconventional-resource plays, "everything is in play right now," according to Stephen Trammel, senior product manager of new product development for IHS Inc.

Across the U.S., "we're not leaving any stone unturned," he told more than 700 attendees at the Developing Unconventional Gas conference in Fort Worth recently, hosted by Oil and Gas Investor and E&P. "Wherever there is shale, it's being looked at."

In addition to well-known shales such as the Barnett and Marcellus, other plays are gaining attention such as the Percha in West Texas, the Pearsall in South Texas, and the Niobrara and Lewis in Colorado. The Barnett/Woodford expansion in the Permian ...