Coalbed Methane Potential of the Appalachians

Abstract

The paper was presented at the SPE/DOE Unconventional Gas Recovery Symposium of the Society of Petroleum Engineers held in Pittsburgh, PA. May 16–18, 1982. The material is subject to correction PA. May 16–18, 1982. The material is subject to correction by the author. Permission to copy is restricted to an abstract of not more than 300 words Write: 6200 N. Central Expwy., Dallas, TX 75206. Abstract Coal mines in the Appalachian Basin emit approximately 180 million cubic feet (MMcf) of high-quality methane into the atmosphere daily. The existence of mines in West Virginia, southwest Virginia, eastern Kentucky, Ohio, Pennsylvania, Tennessee, and Alabama with high gas emissions of over 100 thousand cubic feet per day (Mcf/d) suggests that further investigation into the economic development of this unconventional energy source is warranted. Appalachian coals occur as multiple beds, individually up to 14 feet thick (Pittsburgh coalbed in Pennsylvania and West Virginia). The gas content of these bituminous coal seams has been measured at 93 cubic feet per ton (cu ft/t) from a depth of 149 feet (Waynesburg coalbed, Pennsylvania) to over 560 cu ft/t at 1,764 feet (Pocahontas Pennsylvania) to over 560 cu ft/t at 1,764 feet (Pocahontas No. 3 coalbed in West Virginia); in the anthracite region, 690 cu ft/t have been measured where the overburden is 685 feet thick (Peach Mountain coalbed). Detailed studies in the southern Warrior Basin indicate the presence of up to 20 trillion cubic feet (Tcf) of gas, and preliminary work in the Central and Northern Appalachian Basins suggests a resource of 50 and 80 Tcf, respectively. Many coal operators are realizing the production potential of coalbed methane. In Buchanan County, Virginia, the Island Creek Coal Company produced up to 434 Mcf/d from 12 horizontal boreholes drilled into the mine face. Waynesburg College in Pennsylvania will realize a savings of $25,000 toward their annual energy bill from a 1,450-foot vertical well drilled on campus. In Alabama, U.S. Steel's mines just began commercial production, and sold 25 Mmcf to a gas pipeline company in December 1981; and Jim Walters Resources has begun an ambitious program to drill up to 700 wells with a predicted total production of 60 billion cubic feet (Bcf). production of 60 billion cubic feet (Bcf).These examples of the successful exploitation of a resource formerly considered only a hazard to coal mining indicate a promising future for coalbed methane. Introduction Since the mid-1800s, coal mines in the Appalachians have had a history of mine disasters related to the gassy coalbeds throughout the area. These problems continue despite modern safety methods because active mines are pushing deeper into virgin seams with higher relative gas contents. For Appalachian mines in 1975, the methane emission rates totaled over 180 MMcf/d; and for individual mines, rates can be as high as 11.6 MMcf in the Loveridge Mine in Marion County, West Virginia. Conversely, this potential hazard can be an energy resource to be developed either in conjunction with mining or independently. To further investigate the potential of this resource, in 1977 the U.S. Department of Energy (DOE) began the Methane Recovery from Coalbeds Project (MRCP) to characterize and help to develop Project (MRCP) to characterize and help to develop its utilization. In addition to government-sponsored research and development, numerous commercial firms—many located in the Warrior Basin— have become involved with coalbed methane's characterization and exploitation. TRW has been involved since the inception of MRCP in the collection and analysis of data, and we are now attempting to collate the findings to form a coherent picture of the coalbed methane resource potential for the entire Appalachian region. The potential for the entire Appalachian region. The object of this paper is to explore the magnitude and potential of this resource throughout the Appalachian Basin. PHYSIOGRAPHY/GEOLOGY PHYSIOGRAPHY/GEOLOGY The coal-bearing Appalachian Basin extends over parts of nine states (Figure 1), and includes the following subdivisions: the Northern Appalachian, Central Appalachian, and Southern or Black Warrior Basins. P. 125