The goal of this project is to provide essential baseline information necessary for the development and production of potentially extractable coalbed methane (CBM) from areas in the Illinois Basin.

University of Kentucky (Kentucky Geological Survey)
Illinois State Geological Survey 
Indiana Geological Survey

Location:
Lexington, Kentucky 40508

This project will perform a detailed geological assessment for part of the Illinois Basin covering areas of Kentucky, Illinois, and Indiana. The results of this assessment will be used to identify target areas for drilling three exploration core holes, from which coals and selected organic-rich shales will be recovered and tested for gas content. Some samples will undergo further analyses to determine absolute gas saturation (adsorption) capacity, as well as the stable isotopic characteristics of the gas. In addition, a pilot production well in southern Illinois will be drilled to determine in-situ gas content, coal permeability characteristics, and gas production capabilities.

Geological assessment of the remainder of the basin will be conducted during the second phase of the project. Four addition conventional exploration core holes will be drilled as a result of this assessment. Additionally, four wells surrounding the center pilot well will be drilled; all five wells will be stimulated and then put on pump to lower the hydrostatic pressure in the coal and produce gas and water. Dewatering of the pilot production site in southern Illinois will continue for at least one year. A second site will be evaluated using underbalanced, multi-directional, multi-level drilling to evaluate the potential benefit this type of drilling technology holds for CBM production in the Illinois Basin.

The final phase of this project will involve the completion of the analyses of core data and acquisition of at least one year of pilot production site data, as well as an overall assessment and compilation of all of the data collected during the project.

The results of the NETL sponsored project are encouraging industry development of an otherwise wasted natural gas resource in a region surrounded by major Midwest metropolitan centers including: Chicago, Indianapolis, Louisville, and Saint Louis. Over 100 participants from industry and state organizations attended a symposium held November 16 and 17, 2004 in Evansville, Indiana to hear detailed coalbed methane characterization presentations by the three project participating state surveys and several industry groups who are successfully developing this resource. In particular, BPI, Inc. presented results of their Saline County, Illinois “Delta Project” involving a 50 well program (with thirty wells so far completed).

Results:
The accomplishments achieved to date are described below, listed by state.

Illinois – The first well was drilled, logged and cased (to 1,174 feet) in mid- November, 2003. This well, Hon#9, will be the center well of the planned CBM production pilot in White County, Illinois. Eight 20-feet long cores were drilled in this well and core recovery was excellent. They included complete thicknesses of all the major coals expected in the area. A total of over 24 feet of coal was recovered between depths of 750’ and 1115’. Sixteen coal samples and three black shale samples were selected for gas content analysis. The analyses of desorbed gas chemical and isotopic compositions were completed in March 2004.Carbon and hydrogen isotope analyses of the desorbed gases are consistent with data from an earlier drilling program and support primarily a microbial origin of the methane.

Indiana – The effort in Indiana has concentrated on acquiring and processing structural and thickness data for coal beds that have not been previously examined. For these seams—the Hymera, Survant, and Colchester Coal Members—croplines and maps of the thickness and depth were generated. In cooperation with Black Beauty Coal Company, coal cores were obtained and have been completely desorbed. Adsorption isotherm data on three coal samples has been obtained.

Kentucky – In Kentucky, efforts concentrated on developing GIS coverages to identify the most promising areas in the western Kentucky Coal Field for drilling. Using primarily borehole data records, thickness maps were constructed for the following coal beds: Davis, DeKoven, Springfield, Herrin, Paradise, and Baker. An overburden thickness map was also constructed using the Springfield coal bed as a datum. The Springfield coal was used as it is the thickest and most extensive coal bed in western Kentucky. Digital files showing mined out areas were obtained. The position of known faults was assembled using information from geologically-mapped 7½ minute quadrangles. All of this information was combined to form a derivative map that displays the areas with the greatest cumulative thickness of coal, depth of cover to the Springfield coal, mined out areas, and position of known faults.

This project is completed. Overall accomplishments include:

• Initial geologic assessment of Illinois Basin has been completed.
• The basin is estimated to contain approx. 11 Tcf of CBM with very limited production to date.
• First well in the Illinois area of the basin was cored in White County, Ill., yielding a cumulative bed thickness of 24.5 ft (individual beds range from 1.4 to 5 ft.). CBM gas contents range from 83.3 to188.7 scf/ton of coal.
• PTTC Meeting in Evansville, Indiana on Nov. 16-17, 2004 featured this project.

This project is completed

 Phase I - $500,000; Phase II - $667,292; Phase III - $283,820

Phase I - $374,440; Phase II - $907,597; Phase III $175,760

NETL - William Gwilliam (304-285-4401 or william.gwilliam@netl.doe.gov)
UKY - Cortland F. Eble (859-257-5500, ext. 149 or eble@kgs.mm.uky.edu)

USGS Factsheet - A Rebirth of the Illinois Basin