Study of Sulfosuccinate and Extended Sulfated Sodium Surfactants on the Malaysian Crude/Water Properties for ASP Application in Limestone

Among the successful methods in enhanced oil recovery (EOR) is the chemical EOR. The surfactant-based chemical techniques are highly recommended. However, some drawbacks remained unsolved such as surfactant selection and application in the reservoirs. Surfactants are particularly applied in sandstone reservoirs, so paving the path to expand the implementation to limestone reservoirs is required. Recently, alkaline surfactant polymer (ASP) was suggested for limestone reservoirs in Malaysia. However, limited studies discussed the effect of surfactant screening on the process. Thus, this study investigates the influence of sulfosuccinate and extended sulfated sodium surfactants in improving ASP performance. The evaluation considered the interfacial tension, wettability and recovery factor. The approach used was two-stage experiments of surfactant analysis and ASP core flooding. The first step used the drop Kruss spinning drop tensiometer, and data physics equipment drop shape analyzer to analyze the IFT and the contact angle. The second stage included the limestone sandpack preparation and characterization, followed by ASP flooding. The results showed that single surfactant has low IFT between 0.005 and 0.05 mN/m, while significantly, the synergy of surfactant mixtures has ultra-low IFT of 0.0006–0.001 mN/m. The contact angle results showed a drastic alteration of 65–81% reduction. The cationic surfactants achieved complete water-wet on limestone. The sandpack preparation confirmed acceptable uniformity by the histogram identification. The oil recovery proved additional recovery between 22 and 40%. The results of this research are a step forward to attain the technical feasibility of ASP in limestone reservoirs.