RESERVOIR MANAGEMENT STRATEGIES FOR OPTIMIZING RECOVERY FROM ZEIGLER FIELD - A SMALL-SIZED FIELD IN ILLINOIS, USA

One of the causes of the three-fold increase in the number of well aba ndonments in Illinois since 1987 has been difficulties encountered in waterflooding small heterogeneous reservoirs. This paper highlights so me development strategies used in a successful waterflood project in Z eigler Field, Illinois, which should be applicable to other similar re servoirs. Reservoir management strategies at Zeigler Field included ob taining core and log data from almost every well, detailed DST data, b ottom-hole pressure surveys and production/injection surveillance. The se information-gathering efforts enabled the operators to locate major permeability barriers; this allowed optimum placement of water inject ors in the field and relatively high ultimate oil recovery. The waterf lood performance of the Zeigler Field was evaluated with an integrated 3-D geologic and reservoir simulation model. Direct linkage of the ge ologic model and reservoir simulator allowed both models to be greatly improved during the course of the simulation process. Results of the study included: (1) geological model of the study area (2) evaluation of waterflood recovery efficiency and identification of a bypassed reg ion, (3) comparison of alternative oil recovery strategies for optimal incremental production.