Wettability alteration with smart water in carbonates: Effect of different temperatures, pHs and concentration of sulfate and NaCl

The adjusting of ionic composition of water injection in the reservoir can improve oil recovery. The mechanism of injecting water composition in carbonate reservoirs is not known very well but the main reason for improving oil recovery come back to crude oil/injection water/formation water/surface rock interaction. The crude oil/injection water/formation water/surface rock system is very complex for study so it must be change to two by two system with decreasing some items. In this study, the focus is on injection water and oil wet carbonate rock. Wettability is a very important factor in the oil recovery mechanisms. Because it has drastic effect on the distribution and flowing of the oil and water in the reservoirs. Ionic composition adjusting of water which is referred as smart water is known as one of wettability alteration methods in the carbonate reservoirs. Although the mechanisms behind of this technic didn’t have recognized as well but wettability alteration is a result of these mechanisms. The effect of individual ions must be investigate for better recognition of mechanisms causing improving oil recovery. In this study, the aim is the wettability alteration deal with smart water using sessile drop method for contact angle measurements. The effect of sulfate multivalent anion in different temperatures, pHs and concentration of it and NaCl concentration was studied. In upper temperatures the effect of smart water is better and the salinity of NaCl lower the performance of solutions. In acidic pH the solutions have weaker effect than pH of 7and in basic medium the solutions have lowest effect on wettability alteration.

Keywords:

oil recovery , smart water , sulfate , pH , temperature , ion , wettability alteration