The low recovery factor of different reservoirs has rendered enhanced oil recovery (EOR) techniques very vital and important for the oil industry. As one of the most widely used methods in EOR, gas injection has a significant role to play in recovering residual oil in reservoir. Due to low viscosity and high velocity of gas in a porous medium, gas movement always faces the challenge of rapid breakthrough in the reservoir, resulting in volumetric sweep efficiency that does not increase significantly. Foam is a way to deal with the challenges associated with gas injection. Due to its resistance to movement, foam, which contains a large volume of gas and some liquid, will improve the volumetric sweep efficiency EOR process compared to gas injection and increase the breakthrough time. Foam bubbles are formed by the interaction of surface-active materials with the liquid/gas interface. Zeta potential is an effective parameter for eva‎luating surface interactions. In the present study, the effect of zeta potential on the stability of CO2 foam composed of liquid including SiO2, ZnO and Fe2O3 nanoparticles and Sodium Dodecyl Sulfate (SDS) surfactant has been investigated. The results showed that the presence of nanoparticles increased the stability of the foam. Based on BET analysis, the size of nanoparticles affected foam stability. When the specific surface area of nanoparticles increases, the foam stability decreases. Thus, ZnO, which has the lowest BET number, has the greatest foam stability. Based on the eva‎luation of zeta potential at different pHs and its effect on the stability of the foam, the obtained results showed that by increasing the pH to a certain range (base) for all three nanoparticles, the stability of the foam increases. The general eva‎luation of the results of the effect of zeta potential showed that there is an inverse relationship between zeta potential and foam stability, so that the lower the zeta potential, the more stable foam will be formed. eva‎luation of foam stability at different concentrations of nanoparticles showed that the behavior of the system can be divided into three ranges: low nanoparticle concentrations where the surfactant has the dominant effect on lamella formation, high nanoparticle concentrations where nanoparticles have the dominant effect on lamella formation and the range between these two that surfactants and nanoparticles have a positive interaction. The results of the nanoparticle concentration eva‎luation showed that the foam stability decreases in the areas where surfactant and nanoparticles have a dominant effect, while the foam stability is maximum at an optimal concentration. This optimum concentration for SiO2, ZnO and Fe2O3 nanoparticles in solution containing SDS surfactant is 0.06, 0.04 and 0.02 %wt, respectively. In another part of the results, it was shown that the nanoparticles alone will not be stable in aqueous solution, while the presence of SDS surfactant will make it more stable and also form a more stable foam

عليرضا خزعلي، محسن محمدي

حميدرضا شاهوردي، روح اله هاشمي