--> Rocky Mountain Analogs Enhance the Worldwide Potential of Coalbed Gas, by D. K. D. Murray; #90986 (1994).

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Abstract: Rocky Mountain Analogs Enhance the Worldwide Potential of Coalbed Gas

D. Keith D. Murray

Laramide-age basins in the Rocky Mountain region of North America contain the most significant and deepest coalbed gas production in the world. The most prolific production comes from the San Juan basin, Colorado and New Mexico, where some 2,100 wells produce more than 1.4 billion cu ft/day (39,644 M cu m/d) from Upper Cretaceous coals. In the overpressured parts of the basin, individual wells have gauged from five to 20-plus MM cu ft/d (142 M to 566 M cu m/d). The deepest coalbed gas production of record is from Mesaverde Group (Upper Cretaceous) coals in the Piceance basin, western Colorado, at depths ranging to approximately 8,800 ft (2,682 m). An experimental well located in the Deep basin, Alberta, drilled ten years ago, flowed modest volumes of methane from Lower Cretaceous coal at a depth of about 10,000 ft (3,048 m) before the hole was abandoned due to downhole problems.

The wide range of depth, structural, pressure, hydrologic, and other regimes present in Rocky Mountain coal-bearing basins has stimulated a number of important field research projects, many co-sponsored by the Gas Research Institute and private industry. These ongoing efforts have resulted in significant advances in the drilling and completion of coalbed gas wells. This developing technology promises not only to increase reservoir permeability (e.g., by cavitation), thereby increasing well productivity, but also to significantly increase recovery factors (e.g., by nitrogen flooding).

Successful transfer of the technology being developed in Rocky Mountain basins to coal deposits in other regions is expected to greatly enhance the commercialization of coalbed gas in many parts of the world under a wide variety of conditions. The target truly is immense: in-place coalbed gas resources of the world have been estimated at between 4,000 and 7,000 Tcf (113.27 B and 198.22 B cu m). The judicious application of Rocky Mountain analogs will assist many nations in the development of indigenous supplies of this efficient, clean-burning fuel, thereby furthering their economies and effecting important reductions in atmospheric pollution.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994