International Journal of Coal Geology, Vol.38, No.1, 47-59, 1998
Relative importance of physical and economic factors in Appalachian coalbed gas assessment
In the 1995 National Assessment of Oil and Gas Resources prepared by the U.S. Geological Survey, only 20% of the assessed technically recoverable Appalachian Province coalbed gas resources were economic. Physical and economic variables are examined to explain the disparity between economic and technically recoverable coalbed gas. The Anticline and Syncline plays of the Northern Appalachian Basin, which account for 77% of the assessed technically recoverable coalbed gas, are not economic. Analysis shows marginal reductions in costs or rate of return will not rum these plays into commercial successes. Physical parameters that determine ultimate well recoverability and the rate of gas recovery are primary reasons the Northern Appalachian Basin plays are non-commercial. If the application of new well stimulation technology could offset slow gas desorption rates, Appalachian Province economic gas could increase to more then 70% of the technically recoverable gas. Similarly, if operators are able to develop strategies to selectively drill plays by avoiding dry holes and non-commercial occurrences, the economic fraction of technically recoverable gas could increase to over half.