With all of the recent headlines about massive natural gas shale plays in the Appalachian Basin, across Texas, Louisiana and British Columbia, some may have forgotten about the Rocky Mountains. However, by at least one estimate, there are seven multi-Tcf plays — and maybe more — trapped inside those big rocks waiting for discovery, said Wood Mackenzie researchers.

The report issued Wednesday, “Seven Shale Gas Plays Emerge in the Rockies,” outlines seven plays in formations in six basins stretching across the Rockies that range in depths of 3,000 feet to 16,000 feet. The plays, said Wood Mackenzie, typically contain multiple pay zones and solid production potential.

Included among those promising shales still to be tested for gas resource potential are the:

Most of the shales studied by the UK-based energy researcher already have some exploration wells, which have been drilled by various producers over the course of several decades. However, some of the shale plays, including the Lewis Shale, now are getting long looks not only because of higher prices but also because of new technologies that have improved field economics.

Wood Mackenzie researchers are intrigued by the possible reserves potential from all of the shales. However, based on information released by producers — and a lot of information still remains proprietary — Cane Creek in the Paradox Basin of Utah stands among the “highest performing play” based on initial well results.

The Cane Creek play, at depths of 5,000-9,500 feet, is 85-100 feet thick. According to data, initial drilling results have been estimated at 4,000-12,000 Mcf/d, and the estimated ultimate reserve (EUR) recovery rates are up to 6 Bcf. Well costs are in the $5.5 million range.

If Cane Creek’s EUR numbers stand, the shale’s output could be in the same league as the Barnett Shale of Texas, where average output is around 3.8 Bcf/d, noted Wood Mackenzie.

Meanwhile, the Baxter Shale in the Vermillion Basin also is high on the list of prospects. The basin may have some of the largest gas-in-place resources of any U.S. shale, according to Wood Mackenzie. Although it’s in early stage testing, the play is estimated to contain 440 Bcf/square mile. For now, development has been limited by the high well costs (up to $7 million each) and initial output rates of 1,000-2,500 Mcf/d, which are considered low.

Also on the radar screen of a growing number of prospectors is the Pierre Shale. Interest in this Rockies play was piqued after Pioneer Natural Resources Co. disclosed that its testing estimated that its holdings contained around 2 Tcf of recoverable gas. Now XTO Energy Corp. and El Paso Corp. also are testing wells in the play; results have not been publicly disclosed. And the potential of the Gothic and Cody shales remains a question mark pending more well tests, said Wood Mackenzie. Bill Barrett Corp., a leading stakeholder in the Gothic play, is encouraged, and said it expects to have some results on its initial wells by the end of the year.

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