The use of nanoparticles (NPs) for foam stabilization to enhance oil recovery has shown great promise in oil and gas development. It has been proven that NPs-based foam stabilizers achieve good foam stability. We chose four kinds of surfactants, including a cationic surfactant (CTAB), an anionic surfactant (SDBS), a nonionic surfactant (TX-100), and a zwitterionic surfactant (OA-12), to investigate the influences of hydrophilic NPs on the stability of the CO2 foam. We determined the effects of the surfactant concentration, NPs concentrations, temperature, and salinity on the stability of the CO2 foam. According to previous investigation, a better synergistic effect was assumed to generate between NPs and OA-12 because of opposite charge and shorter molecular chain. The experimental results showed a synergistic effect between the hydrophilic SiO2 NPs and the zwitterionic surfactant. When CO2 was dissolved in an aqueous solution, the solution turned acidic and the zwitterionic surfactant exhibited cationic ...