Low Salinity Water Injection for EOR

Abstract

Abstract Low Salinity Waterflooding is one of the emerging oil recovery techniques which has gained its popularity in the past decade. Many experiments and laboratory works have been conducted since its oil recovery potential was discovered in late 1960s. Wettability alteration in the reservoir is said to be the main cause in enhancing oil recovery. Nevertheless, the effectiveness of this type of oil recovery is very much dependent on the initial reservoir conditions, in particular, the connate water saturation, rock physics and connate water salinity. This work is to run simulations on ECLIPSE 100 simulator to show the effect of injecting low salinity water into a reservoir. A simple static model was created to mimic a real reservoir. Reservoir is of three phase with oil, gas and water and consists of one injector and one producer just to simulate the effect of injecting a low salinity water and a normal salinity, or seawater. Effect on oil recovery was observed by conducting sensitivity studies on rock physics; both injection and reservoir brine salinity; tertiary recovery option; polymer injection using low salinity water solution; and grid refinement. A difference of 14% in oil recovery is observed when lower salinity water is used to inject compared with normal salinity water. The effect on oil recovery also showed distinct difference when the connate water salinity is changed with difference up to 28% with low saline reservoir water. Polymer injection with low salinity water gave 4% increment in recovery compared to injecting with higher salinity water for the same concentration of polymer. This can indeed give better cost savings when opting for polymer injection, where a lower concentration or amount of polymer is needed with the use of low salinity water.