Coalbed methane's growing contribution to U.S. gas production and reserves has substantial scope for even further expansion, says a report by Gas Research Institute, Chicago.
One estimate indicates that with current technology coalbed gas production from the three most productive basins may reach 2.5 bcfd by 1995 and stabilize thereafter.
With refinement of production technology and expansion into currently nonproducing areas, production could rise to more than 3.5 bcfd in 2000, predicts Advanced Resources International Inc., Arlington, Va.
Coal gas accounted for 3% of U.S. gas production during 1992 and 5% of proved reserves at yearend 1992, notes the U.S. Energy Information Administration.
GRI points out that the extent of current development represents only a fraction of the estimated 400 tcf of coalbed methane resource in place in U.S. basins. The most recent estimates of technically recoverable gas range from 62-13-5 tcf.
WHERE IT'S GROWING
Nearly 5,500 coalbed wells contributed 1.5 bcfd of new natural gas supply in 1992. That was 70% higher than the 324 bcf produced in 1991 and nearly three times 1990 output.
Of the 550 bcf produced during the year, 9617, came from the San Juan and Black Warrior basins. The American Gas Association estimated reserves in the two basins at a combined 11.4 tcf at yearend 1991.
San Juan basin "fairway" coalbed wells average 2-3 MMcfd/well owing to the dynamic open hole cavity completion technique, while new multi-seam completions and remediated wells in Alabama are producing at rates as high as 300-400 Mcfd, GRI said.
Important new drilling and commercial production are under way in the Central Appalachian, Arkoma, Cherokee, Piceance, Powder River, and Uinta basins, and less vibrant activity is reported in the Forest City, Green River, Illinois, Northern Appalachian, and Raton basins and western Washington State.
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