Effects of concentration and size of TiO2 nano-particles on the performance of smart water in wettability alteration and oil production under spontaneous imbibition

Using smart nano-fluids with respect to enhanced oil recovery (EOR) is an emerging technology, which is normally studied in combination with other methods. Nano-fluid performance depends on type, size and concentration of the dispersed nano-particles in it. In the current work, effects of size and concentration of seawater-based nano-fluid of TiO2 in different salinities (resulted from dilution) on enhanced oil recovery parameters including contact angle, wettability and interfacial tension (IFT) have been investigated using the pendant drop method. Eventually, effect of TiO2 nano-particles in nano-fluids on recovered quantity has been investigated using imbibition experiment mechanism, which is one of the most important mechanisms in oil production from fractured reservoirs. Results of the experiments show that using higher concentration and smaller particle sizes of TiO2 would decrease the IFT and contact angle. Higher concentration and larger particle sizes of TiO2 in nano-fluid would increase the viscosity. Imbibition experiments show that the nanofluids containing smaller TiO2 nanoparticles are more efficient.