Implications of Low Salinity Water-Surfactant Flooding in Field Applications

One major problem faced by petroleum industry all over the world is that even after application of conventional oil recovery methods, a large portion of oil is left trapped in many oil reservoirs. The main force behind this entrapment of unrecoverable oil is the combination of capillary forces and strong adhesive forces between the oil and the rock matrix. A relatively new hybrid enhanced oil recovery (EOR) method gaining prominence at present times which can be designed to overcome these limitations is the Low salinity water–surfactant flooding. The process improves oil displacement by combining the benefits of low salinity water injection and surfactant flooding. Low salinity water injection leads to alteration of rock wettability and surfactant flooding reduces interfacial tension between oil and water thereby improving oil recovery. This combined technique improves the displacement and flow of trapped oil. Laboratory studies have shown remarkable improvement in oil recovery; however, field-scale application involves various challenges- operational, environmental, and economic. This paper explains the proposed mechanisms, advantages, limitations, practical applications, and future prospects of this method.