PERFORMANCE EVALUATION OF ALPHA-OLEFIN SULFONATE (AOS), COCO GLUCOSIDE AND DECANE IN CREATING WINSOR TYPE-III MICROEMULSION

Abstract

Enhanced oil recovery (EOR) shows great potential in maximizing the recovery of bypassed oil remains unrecovered in the reservoir after applying conventional oil recovery methods. Surfactant injection is a chemical enhanced oil recovery method that can improve the overall displacement efficiency and increase hydrocarbon production. The application of surfactant flooding is challenging due to the complexity of the design. On top of that, most of the utilized surfactants are not environmentally friendly. The formulation of the microemulsion system directly impacts the success of a surfactant injection process. Good understanding on the phase behaviours of the microemulsion system is essential to create Winsor Type-III microemulsion that has the ability to reach ultralow Interfacial Tension (IFT) with the addition of co-surfactant. The performance of the microemulsion also highly depends on factors such as salinity, surfactant type, surfactant concentration, and temperature. Extensive laboratory investigation along with phase behaviour studies are vital in formulating an efficient green microemulsion system for tertiary recovery processes. This project evaluates and presents the performance of anionic surfactant, Alpha-Olefin Sulfonate (AOS), Coco Glucoside, and decane in creating Winsor Type-III microemulsion. The performance of the formulated microemulsions under various salinities, surfactant concentrations, co-surfactant concentrations and temperature are investigated through stages of phase behavior studies to optimize the parameters. The optimized formulation of AOS-Coco Glucoside microemulsion consists of 3 wt% salinity, 1 wt% AOS, and 1 wt% Coco Glucoside as the widest range and maximum volume of Winsor Type-III was observed at this condition. IFT of the microemulsion system was measured at 25°C and 70°C using a spinning drop tensiometer. It is concluded that the formulated microemulsion system with the optimized parameters reaches low IFT instead of ultralow. The temperature has no significant effect on the IFT performance of the formulated microemulsion system, and the critical micelle concentration is determined to be at 0.05 wt% of the aqueous phase.Keywords: Surfactant flooding, microemulsion system, ultralow interfacial tension, environmental friendly surfactants