Tim Hower¹, Jim Morgan², J. W. Rector³, Doug Eden², P. M. Caserotti⁴, P. A. Witherspoon³

(1) Malkewicz Hueni Associates, Golden, CO
(2) Illinois Power Company, Decatur, IL
(3) University of California, Berkeley, CA
(4) Consultant, Mt. Vernon, IL

ABSTRACT: Reservoir Simulation of the Hillsboro Gas Storage Field -- Success via Integration of 3D Seismic and Reservoir Characterization

At the end of 1998, the American Gas Association identified 51 aquifer gas storage projects operating in the US with a total volume of 1.255 Tcf in storage. One of these early aquifer projects was initiated by the Illinois Power Company in 1973 in their Hillsboro Storage Field located in Montgomery County, Illinois. Injection of gas started in August of 1973, and the storage reservoir was steadily developed so that by the end of 1979 the total gas in storage was 10.2 Bcf. Due to increased demand, the storage field was expanded from 1991 - 1993 with the total gas volume increased to 21.7 Bcf. The initial working volume after the expansion was 7.6 Bcf, however this volume declined steadily over the next seven years.

A review of the possible factors that could have contributed to the significant decrease in gas withdrawal volumes from the Hillsboro Field led to a decision to acquire a 3D seismic survey across the field to obtain a better understanding of the geological structure and the reservoir characterization. The end product was a reservoir simulation model, based upon the integrated geology and geophysics, that has been used to optimize the field performance. In addition, the model results and the 3D seismic attribute mapping led to the drilling of a new well in the field in late 2000. This paper presents the interpretation of the geology and 3D seismic, the incorporation of that data into a sophisticated reservoir simulation model, and the results of the model studies and recently drilled well.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado