Performance of sea water dilution on the surface free energies of the crude oils in water-flooded carbonate rock

Although several investigations have studied the low-salinity water injection (LSWI) performance during the past decades, the effect of crude oil type on the interfacial tension (IFT) and wettability alteration is still in dark. In this regard, this study is aimed to obtain the thermodynamic energies including adhesion, cohesion and spreading coefficient during LSWI. To achieve this goal, IFT and static contact angle values of three different crude oils (i.e. light, medium and heavy) are measured as a function of sea water salinity. The obtained results revealed that the dilution of sea water can change the wettability of reservoir rock from oil wet state towards water wet state, while crude oil type implies no significant effect on the wettability alteration. Besides, the results illustrated that although the dilution of sea water unfavorably changed the IFT of light and heavy crude oils, it could favorably change the spreading coefficient.