Simulation of Low Salinity Waterflooding in a Fractured Carbonate Reservoir: Case Study

Low salinity waterflooding (LSW) is an applicable, simple and cheap enhancedoil recovery (EOR) technique for improving oil recovery from sandstone andcarbonate reservoirs. The main mechanism of improving oil recovery by lowsalinity water flooding is wettability alteration and residual oil saturationdecrease. In this study, a sector of a fractured carbonate reservoir is modelledand low salinity waterflooding is simulated for a 10-years period bySchlumberger s ECLIPSE100 reservoir simulator. The results show that lowsalinity waterflooding has low effect on this sector such that lowering theinjected water salinity from 40,000 ppm (sea water salinity) to 1000 ppm yieldsa difference of 0,013% based on original oil in place (OOIP) in ultimate recovery.This value is equivalent to about 50,000 STB more recovery in a 10-yearsperiod, that is negligible. Moreover, if the field water salinity decreases from123,000 ppm (initial salinity) up to 30,000 ppm, the difference in ultimaterecovery is about 0,277% based on original oil in place (equivalent to about1,100,000 STB); but this assumption is impossible in nature and not applicable.The main reason of failure of low salinity waterflooding process in this sector isrelated to favorable wetting condition that is intermediate while low salinitywaterflooding technique is more efficient in oil-wet reservoirs.

کلیدواژه ها:

Low salinity waterflooding ، Enhanced oil recovery ، Reservoir simulation ، Fractured carbonate reservoirs ، Wettability alteration