Reservoir Heterogeneity in Illinois Basin: Program Focused Toward Independent Producer

Donald F. Oltz, H. W. Bang, J. E. Crockett, B. Seyler, S. T. Whitaker, J. D. Yeko

The Illinois State Geological Survey, in cooperation with the U. S. Department of Energy (DOE), has implemented a major research effort intended to identify and maximize recovery of unswept mobile oil in existing fields. Emphasis is on practical and applicable research that can be transferred to the oil operator at the earliest opportunity. The USGS estimates that the original oil in place for known fields in the Illinois basin is 11.75 billion bbl. DOE ranks Illinois as ninth in the nation with 1.453 billion bbl of unswept mobile oil as an important target.

The identification of the critical parameters that influence hydrocarbon recovery and their distribution is accomplished through a program integrating geology, geophysics, geochemistry, petroleum engineering, and economics. Program elements are: screening and prioritization, geologic framework, characterizing heterogeneity, database design and management, reservoir classification, field appraisal, and technology transfer.

Results of the studies will allow infill wells to be geologically targeted and aid in the engineering design of advanced extraction techniques. Specific effects of completion and stimulation techniques and their variability from reservoir to reservoir will be documented in order to improve oil recovery.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.