Experimental Design of Factors Influencing WAG Performance in a Sandstone Reservoir

Abstract

For decades there has been an interest in water alternate gas (WAG) injection. WAG injection improves oil recovery on both microscopic and macroscopic levels by combining the benefits of conventional waterflooding and gas injection. This research is aimed at the optimization of WAG injection. The investigated field case study is named Volve, which is a decommissioned sandstone field in the North Sea. Experimental design of factors influencing WAG performance on this base case was studied. The following parameters were considered; WAG ratio, time to start WAG, total gas slug size, cycle slug size, and tubing diameter. A full two-level factorial design was utilized for the sensitivity study. Sensitivity study results showed that the total slug size is the most important parameter followed by time to start WAG, and then cycle slug size. WAG ratio appeared on some of the interaction terms while tubing diameter effect was found to be negligible. The study also showed that phase hysteresis has no effect on oil recovery.

Date of Award	May 2021
Original language	American English