Abstract

Comparative Study on Oil Recovery Enhancement by WAG Injection Technique in a Fractured Oil Reservoir in the Southwest of Iran

Hajnajafi Reza, Amid Arman and Hajnajafi Ghazal

Water alternating gas injection (WAG) and simultaneous water and gas injection (SWAG) are injection techniques used to enhance oil recovery. Gas injection is today regarded as the second method for increasing oil recovery. While very little oil remains in the areas swept by gas, the amount of volumetric displacement by injected gas has always drawn much concern. This is due to high mobility ratio of the gas injected to reservoir oil. To solve this problem, WAG and SWAG injection techniques are used to control fluid flow profile. High microscopic displacement efficiency of gas (in whole scale) and high volumetric displacement efficiency of water (in microscopic scale) considerably increases oil recovery in the front space of water. In this paper, we investigate various WAG injection methods using Eclipse and compare the results to determine the best injection scenario for the reservoir under study.