Synergistic Effect of Surfactant and Salt Mixture on Interfacial Tension Reduction between Crude Oil and Water in Enhanced Oil Recovery

In the present paper the effect of salinity and different surfactants on interfacial tension (IFT) between crude oil and water has been investigated. Three different types of surfactants like anionic (sodium lauryl sulfate [SLS]), cationic (hexadecyltrimethylammonium bromide [HTAB]), and nonionic surfactants such as Tergitol 15-S-7, Tergitol 15-S-9, and Tergitol 15-S-12, respectively, have been used in this study. Improved efficiency of IFT reduction using a salt and surfactant mixture has been verified by measuring the IFT between oil and water. The synergism of salt and surfactant mixture on the reduction of IFT has been observed. A series of flooding experiments have been conducted to justify the effects of lowering interfacial tension and adsorption behavior of surfactants on additional oil recovery. It has been found that the additional oil recovery increases up to 24 % of the original oil in place (OOIP) when a surfactant and salt mixture has been used as the displacing fluid.