Seismic Monitoring of Methane Production from Coal Seams in Illinois
Gas Technology Institute, with support from the Illinois Clean Coal Institute and cooperation of the Illinois State Geological Survey, designed and implemented a comprehensive research project to determine the viability of seismic techniques for site selection and development of coalbed methane production from Illinois coals. The focus of the studies was on viability of seismic techniques for delineation of thin coal seams and tracking of the desorbed gas front by time-lapse (4-D) seismic surveys. Results from these studies would be equally applicable to monitoring of the CO2 front in geologic CO2 sequestration operations as in both cases the physical process involves the presence of a gas phase (CO2 or methane) into initially water saturated coal seams.
Document Type
Report
Report Type
Final Technical Report
Report Period
March 2005 - August 2006
Author(s)
Iraj Salehi
Corporate Source
Gas Technology Institute (GTI)
Sponsor
Illinois Clean Coal Institute; Illinois State Geological Survey
Seismic Monitoring of Methane Production from Coal Seams in Illinois
The issue of seismic resolution relative to thin coal seams was investigated in a series of seismic surveys that included surface seismic, vertical seismic profiling, and crosswell seismic imaging. Results were positive and encouraging. The data proved that thin coal seams can be reliably mapped by properly designed seismic surveys. The first leg of the 4-D seismic survey was completed and the second leg awaits the onset of gas production at the ISGS site in White County, IL; expected to occur in late 2006 or early 2007. GTI will fund this survey at its own cost estimated at about $29,000.00. Results from the 4-D survey will be submitted to ICCI as an addendum to the present report.
In the course of the project, the scope of work was expanded to include the study of hydraulic fracturing (a well completion technique used for enhancing gas production from coal seams and tight sands reservoirs) in south and south-central Illinois. The industry partner for these efforts was BPI-Energy. Hydraulic fracturing research involved forward modeling, fracture design, and fracture diagnostics. The work was performed with support and participation of BPI-Energy engaged in a coalbed methane production project in Shelby County, Illinois. The work was completed in July, 2006. Results from fracture modeling showed that fracture containment at this site would be very low and nearly all vertical fractures would grow out of zone. Fracture diagnostic survey proved that hydraulically created fractures were complex and except for the shallow seams where fractures were horizontal, all fractures had one vertical component and at least one horizontal component.
