Microscopic Mechanical Model Analysis and Visualization Investigation of SiO2 Nanoparticle/HPAM Polymer Foam Liquid Film Displacing Heavy Oil

In this paper, the microscopic mechanisms and macroscopic characteristics of polymer/nanoparticle foam flooding in a heavy oil reservoir environment were studied. Sodium dodecyl sulfate (SDS) surfactant was used as the foaming agent, and the foam was prepared by a combination of partially hydrolyzed polyacrylamide (HPAM) polymer and SiO2 nanoparticles. By performing experiments with the microscopic model, the foam flooding dynamics in the heavy oil reservoir were simulated. Based on the experiments, the formula model was established to evaluate the physicochemical effects between the foam liquid film and oil surface. Finally, the macroscopic characteristics of foam flooding were studied by performing oil displacement experiments with a 2D visual model. The microscopic experiments demonstrated that the foam liquid film could exert multiple actions, such as adsorption, stretching, and cutting on the heavy oil in the reservoir pores. These actions were accompanied by force changes between the foam and heavy oil, and the addition of polymer and nanoparticles further strengthened them. The calculations of the formula model indicated that the polymer and nanoparticles amplified the force between the foam liquid film and heavy oil by 1.95 and 2.2 times, respectively. The 2D visual model experiments suggested that foam flooding could further develop heavy oil after water flooding through its liquid film effects, and the oil recovery efficiency increased from 42.43 to 57.82%. In addition, the polymer and nanoparticles further optimized the oil displacement effect of the foam liquid film, which made the oil recovery efficiency reach 64.77–68.16%.