Abstract
In order to explore the influence characteristics of SiO2 nanoparticles on the SDS foam flooding in the heavy oil reservoir, in this work, CMC was used as the dividing boundary to prepare foams with different concentrations of nanoparticles and surfactants. Through experiments, the influence laws of nanoparticles on the foam were discussed, and the development process of foam flooding was simulated to study the influence mechanisms of nanoparticles and surfactant concentration on foam flooding. The results showed that the nanoparticles endowed the foams with rigidity, increased the viscosity, reduced the drainage velocity and interfacial energy, and optimized the half-life and viscoelastic modulus of the foam. These changes made the foam structure denser with better strength and stability, equipped it with better pore plugging ability and displacement mobility ratio, which optimized sweep efficiency while generating larger displacement pressure differentials. Finally, the heavy oil recovery rate of nanoparticle foam flooding reached more than 62%, which was much better than those of SDS foam flooding and water flooding. In addition, due to the synergistic effect of surfactants and nanoparticles, foam and heavy oil formed the foamy oil emulsion during the development process, which improved the oil mobility and further optimized the displacement mobility ratio. This emulsification mechanism reduced the heavy oil development difficulty, which was the key that foam flooding was superior to water flooding in the field of heavy oil development.
NSTL