A Simple Mathematical Model to Predict Waterflooding for Reservoirs under Bottom-Water Conditions

SHIRIF, EZEDDIN, U. of Alberta

Many reservoirs in Alberta and Saskatchewan contain a high water saturation zone (bottom-water) underlying the oil zone. Waterflooding under such conditions is typically ineffective because of channeling of water through the bottom-water zone. However, in some cases, waterflooding such reservoirs may still be feasible and economically viable. While there is no doubt that some of the injected water bypasses the oil zone through the bottom-water zone, most of the injected water may still displace the oil, depending on the reservoir conditions. Therefore, a mechanistic understanding of oil displacement by a waterflood in the presence of a bottom-water zone is the basis for predicting recovery performance, and there is a need for developing a mathematical model to describe water channeling under bottom-water conditions. Given the reservoir description, the mathematical model should be able to describe the amount of water channeling into the bottom-water, together with a prediction of oil recovery. In this work, an analytical model was developed to predict waterflood performance when a water zone is present. Results of the mathematical predictions are compared with experimental results, showing good agreement

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California