The Rocky Mountains hold significant shale gas resource potential based on the sheer number of plays being explored, according to U.K.-based energy-research-and-consulting firm Wood Mackenzie’s study of seven shale-gas plays in the Rockies. “The region holds a number of shale-gas plays that have either been overlooked or were produced with other tight-gas plays,” says Connie Lin, upstream research analyst for Wood Mackenzie. “While it is too early to quantify the impact of these plays until they enter the development phase, should these companies succeed, the Rockies could become a major producer of commercial shale gas in the Lower 48.” Lin says operators are ramping up drilling operations. The Wood Mackenzie study profiles the Gothic, Cody, Cane Creek, Baxter, Mancos, Lewis and Pierre shales. The seven plays are in six basins and are in various stages of exploration. Vertical depths range from 3,000 to 16,000 feet and the typical play has multiple pay zones. Initial production rates are highly variable and have reached as high as 12 million cubic feet per day in the Cane Creek play. “The success of the Barnett shale in the Gulf Coast has spurred development of shale gas throughout the U.S.,” Lin says. “While the Rockies region has successfully produced from unconventional resource types, shale-gas plays have largely been untapped. Many of these plays are currently being tested for their commerciality. Some of the other plays have been commingled with other reservoirs and produced for many years.” Lin says preliminary estimates suggest the Cane Creek and Pierre shales each hold multiple trillion cubic feet of gas reserves, with Cane Creek standing out as the highest-performing play based on well results. Others, such as the Baxter, Gothic and Cody shales, are still in the testing phase and their reserve potential are unknown. Baxter has one of the largest gas-in-place resources of any U.S. shale; however, due to the high well cost and low production rates, operators have not yet been able to fully exploit the shale. Lin says the Mancos shale has been produced commingled with other formations and is being tested as a standalone play in the Uinta Basin. Companies are also exploiting the Lewis shale as a separate play in the Greater Green River and San Juan basins.