Experimental Assessment of Hybrid Low Salinity Water and Polymer Flooding (LSPF) for Wettability Alteration of Oil-Wet Sandstones Reservoirs

Low salinity water flooding (LSWF) is one of the Enhanced Oil Recovery (EOR) methods that has recently received much attention. Research studies show the fact that change of contact angle from the oil-wet towards water-wet can improve the production in the water injection process, depending on therock/water/oil balance. Therefore, in different oil reservoirs, the optimal salinity and composition of injected water can be different based on the crude-oil/water/rock (COBR) system. As a result, it is necessary to consider recognizing the effect of salinity and optimal composition of injected water on theinitial equilibrium water/oil/rock system. The main goal of this research is to investigate the effectiveness of hybrid low salinity and polymer on fluid/rock properties of specific oil/rock/brine system from southwest Iran. In this study, the wettability behavior for several aqueous samples wasidentified by measuring the contact angle of crude oil on the quartz slides before and after contact with the brine and polymer solutions. From the experimental results, in the case of ۲xcSW quartz surface shows a very strong oil-wet behavior. Even after adding polymer (۵۰۰ppm and ۱۰۰۰ppm) the changes in contact angle were not significant. However, with reducing the salinity of water (SW), the change of contact angle was remarkable. For instance in the case of quartz/crude oil/SW+۱۰۰۰ ppm HPAM the contact angle changed from about ۱۷۵°, to the ultimate value of ۱۳۰° after ۶۰ hours.

Keywords:

Polymer flooding , Low salinity water , Wettability alteration , HPAM , Chemical EOR