Hydrophobic Silica Nanoparticle and Anionic/Cationic Surfactants Interplays Tailored Interfacial Properties for the Wettability Alteration and EOR Applications

In this study, the effect of anionic and cationic surfactant solutions alone and in combination with silica AEROSIL® R 816 nanomaterial on the wettability alteration of carbonate rock reservoirs has been investigated. The nanofluid properties including stability, surfactant Critical Micelle Concentration (CMC), InterFacial Tension (IFT), and surfactant adsorption were studied in each case, and the synergistic effect of nanoparticles as adjacent particles along with surfactant molecules in the solution with respect to electrostatic and capillary forces has been discussed. The results show that nanoparticles generally reduce ST, CMC, and surfactant adsorption on the rock, and surfactant molecules significantly increase the stability of nanoparticles. Also, contact angle test results indicated an increase in the effect of the wettability alteration of stones in the surfactant solution by the nanoparticles from the lipophilic to the hydrophilic, and the nanopowder solution itself had the most ability to change the wettability. Finally, the results from the observations mentioned above were confirmed by performing an imbibition test based on drop experiments.