Experimental investigation of smart water injection in dolomite rocks

Water flooding has already been shown to be one of the most cost-effective ways to enhance oil recovery in carbonate reservoirs. The main obstacle of this type of reservoir is the low recovery rate due to the oil-wet rock surfaces and modifying the chemistry of water injection could significantly increase oil production. This article aimed at the optimization of salinity and composition of divalent ions in Smart water flooding in dolomite reservoir rocks. Contact angle measurements performed in two steps to screen and select the optimal composition among several types of waters. Core flooding experiments conducted to evaluate the performance of the chosen waters in two different scenarios; It was carried out in three steps including brine (FW) injection, followed by best water (RW) and finally smart water (RW2S) and the second scenario was applied in reverse. Maximum recovery of 59.65% original oil in place (OOIP) was recorded for the second scenario and a lower recovery of 50.72% OOIP was observed for the first. Experimental results confirms that a higher concentration of sulfate ions enhances the water-wetness of dolomite rocks and two main mechanisms behind the smart water injection are wettability alteration and pH increase.