Comparative experimental study of various metal oxide nanoparticles for the wettability alteration of carbonate rocks in EOR processes

Wettability alteration by the nanoparticles is the method has been greatly attracted attention in the EOR processes in the past years. Distinctive features of them, mainly resulting from their small sizes, have introduced nanoparticles as a good wettability modifier in the oil-wet carbonate reservoirs. In this research, different metal oxide nanoparticles, including SiO2, MgO, ZnO, and Fe3O4 nanoparticles, were dispersed in the formation water for the investigation of their potential role in the rock wettability alteration through contact angle measurements. According to the results, a total reduction of 63 degrees was observed for 750 ppm of the Fe3O4 nanoparticles in the formation water, in which 39 degrees were only reduced by the nanoparticles. On the other hand, ZnO nanoparticles indicated the fast wettability alteration at the time the ultrasonication was performed. Generally, MgO and ZnO nanoparticles resulted in the same wettability alteration after 24 hours (from 164 and 166 to 75 and 63 degrees, respectively). The results also showed a considerable contact angle reduction for SiO2 nanoparticles over 24 hours for the concentration of 750 ppm, which is due to the high potential of this nanoparticle for overcoming the available adhesion forces in the system.