Effect of Amphiphilic CaCO3 Nanoparticles on the Plant Surfactant Saponin Solution on the Oil–Water Interface: A Feasibility Research of Enhanced Oil Recovery

In order to solve the serious problem of oil shortage, the improvement of the emulsification effect of surfactants using nanoparticles was proposed to enhance oil recovery. In this work, first, an amphiphilic nano-calcium carbonate (ANCC) was synthesized, and the dispersion effect of ANCC in saponin solution was studied. It can be found from results that the dispersion effect of ANCC was the best in 5000 ppm of saponin solution, and the dispersion rate decreased with the increase of salinity. Then, the effect of ANCC on the emulsion property, interface tension, and expansion modulus of saponin solution was studied. It can be found from results that with the increase of ANCC concentration, the emulsion rate between saponin and crude oil increased, the water extraction rate decreased, the emulsion particle size decreased, the interface tension decreased, the expansion modulus increased, and the emulsion stability became better. At the same time, with the increase of temperature, the interface tension decreased, and the expansion modulus increased. With the increase of salinity, the interface tension decreased first and then increased, and the expansion modulus decreased. Finally, the effect of ANCC on the oil recovery of saponin solution flooding was studied by displacement experiments. It can be found from results that when the ANCC concentration was 100, 500, and 1000 ppm, the oil recovery was increased, respectively, by 18.42, 20.97, and 24.59%, indicating that the oil recovery gradually increased with the increase of the concentration of ANCC. This work is of great significance for enhanced oil recovery in surfactant flooding.