Enhanced oil recovery by alkaline-surfactant-polymer alternating with waterflooding

Abstract

Alkaline-Surfactant-Polymer (ASP) flooding is an efficient method but was poorly applied in the industry as it is costly. The best mixture and injection sequence is also uncertain. The objective of this research work was to determine the best injection design pattern which could reduce the cost while improving recovery via the conventional ASP flooding. The effects of different ASP techniques in terms of injection sequence and mixture on ultimate oil recovery were analysed. In the laboratory work, three types of chemical flooding injection design were evaluated namely, continuous or conventional ASP flooding, alternating ASP with waterflooding, and lastly tapering water to ASP ratio. The recovery for each cycle was recorded and the ultimate recovery was compared. The experimental results showed that ASP alternating with waterflooding gave the best ultimate recovery (68 %), followed by tapering water to ASP ratio (62 %) and continuous ASP flooding (57 %). The ratio of recovery per volume of chemical injected showed that ASP alternating with waterflooding is the best option as it uses the least chemical to yield a higher recovery. The ASP alternating with waterflooding should be considered for field application as it can give the best performance with higher ultimate recovery.