Coalbed Methane (coal gas) is in its second wave of development in the United States. Twenty years ago, it was an unconventional gas play most operators stayed away from. It grew however to be one of the hottest plays of the early 1990’s. The development of successful coal gas fields has come as a result of favorable economic conditions, but also due to strong cooperative efforts among industry and research and development organizations in sharing technical information and experience, and designing research projects specifically geared toward technical issues. During this first wave of development numerous areas containing substantial coal gas resources were left undeveloped. These frontier areas in the lower United States have been estimated to contain over 677 Tcf of coal gas.

The Illinois Basin is still considered a frontier area. The basin was formally evaluated for its coal gas potential in 1979, at which time the amount of Pennsylvanian-age coal was estimated at ~365 billion short tons, having a potential in-place coal gas resource of up to 21 Tcf. However even with such a large potential coal gas resource, only small areas within the basin have seen exploration programs during the past 20 years. Methane gas has been produced from wells drilled into abandoned coalmines in the past providing an energy resource for local uses, but less than 35 actual coalbed gas wells have been drilled in the basin through December 2000.

The Illinois Basin encompasses approximately 53,000 mi2, and is in close proximity to numerous large gas storage fields and gas markets. Having a long history of hydrocarbon activity, the basin contains a well-developed interstate pipeline infrastructure. What are the main factors hindering coal gas exploration in the Illinois Basin? What are the technical challenges that operators have yet to overcome? Will a coordinated basin-wide industry / research effort required to develop more confident estimations of this resource?

This paper focuses on these questions by addressing, the current perceptions of the coal gas resource, the historic and current exploration activity, and the mechanisms effecting coal gas development. As a result, the current technical challenges facing operators are identified. Opportunities to participate in the collection and evaluation of comprehensive reservoir characterization data sets in the basin are presented.

Keywords:
coal seam gas, reservoir characterization, development challenge, coal bed methane, information, gas content, exploration, springfield, coalbed methane, illinois basin
Subjects:
Well & Reservoir Surveillance and Monitoring, Pipelines, Flowlines and Risers, Reservoir Characterization, Unconventional and Complex Reservoirs, Asset and Portfolio Management, Coal seam gas
Copyright 2001, Society of Petroleum Engineers
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