ABSTRACT: Forty-Seven Wells in 40 Acres: A Detailed Reservoir Study of Loudon Field, IL

HOROWITZ, DANIEL H., and N. K. MAER, Jr., Exxon Production Research Company, Houston, TX

An intensive geological-engineering study was conducted on a 40-acre pilot in the Loudon field to plan for, monitor the progress of, and economically evaluate a surfactant flood in the Weiler Sandstone reservoir. What made this study exceptional was the amount of sample control and the number of tests conducted in such a small area. Forty-seven logged wells and 15 cored intervals were used to determine the sequence stratigraphy and guide the construction of a three-dimensional geologic model for flow-simulation studies. Pulse tests between multiple well pairs, single-well tracer tests, periodic logging of three observation wells, and analyses of produced tracers, surfactant, and polymers provided data for monitoring behavior and calibrating the results from simulation. The simulations were helpful in understanding fluid movement, and in one instance revealed the mislocation of one injector.

Many lessons were learned from this project on how to conduct such a reservoir study. For example, problems with quality control during logging and core analyses led to recommendations for modified procedures in future studies. With the recent introduction of geostatistical techniques, it is now recognized that a geologically more reasonable reservoir description is possible, as a comparison with variograms will illustrate.

AAPG Search and Discovery Article #91013©1992 AAPG Eastern Section Meeting, Champaign, Illinois, September 20-22, 1992 (2009)