Wettability alteration with designed water: Effect of borate and sulfate as multivalent anions in smart water composition

The ultimate economic recovery of oil strongly depends on reservoir wettability, which controls pore level displacement processes and the efficiency of oil recovery by waterflooding. Change in injection brine composition, in a way that maintains the oil production rate above the economic limit, would extend the life of these reservoirs. Many studies have done for understanding the role of differentions and salinity of seawater in changing primary wettability of reservoir rock, but a few works is published about role of new ions and their difference with common seawater ions. In this study, theaim is the wettability alteration deal with smart water using sessile drop method for contact angle measurements. The effect of borate and sulfate multivalent anions in different temperature, pH and concentration of them was studied. Modified brines containing borax salt were more effective than sodium sulfate salt. In acidic pH both anions have not good effect but in neutral pH they have biggest effect on wettability alteration toward more water wet. Both anions have good effect on wettability alteration of carbonate rocks.

Keywords:

oil recovery , smart water , borate , sulfate , pH , temperature , ion