Dissipative Particle Dynamics Simulation and Microscopic Experimental Study of Emulsification Performance of Surfactant/Polymer Flooding

Polymers can increase the viscosity of water, reduce the relative permeability of the water phase, and enhance the flowability of the oil phase; surfactants can form molecular films at the oil–water interface boundaries, thereby reducing interfacial tension. Surfactant/polymer (S/P) flooding technology for enhancing oil recovery has become a major way to increase crude oil production. This study used dissipative particle dynamics (DPD) technology to simulate the emulsification process of a four-component composite system consisting of oil, water, sodium dodecylbenzene sulfonate (SDBS), and partially hydrolyzed polyacrylamide (HPAM). By changing the concentration of the S/P system, the effect on emulsification behavior was analyzed. Combined with particle distribution diagrams and interfacial tension parameters, the effect of the emulsification behavior on the performance of the S/P binary system was analyzed. On this basis, the effect of different emulsion performances on the recovery factor was evaluated using micro-experiments. The study found that the S/P system that produced stable emulsification had a lower interfacial tension and relatively good effect on improving the recovery factor. Increasing the concentration of the polymer and surfactant may cause changes in the interfacial film of the emulsion, thereby affecting the ability of the S/P system to reduce interfacial tension and may not improve the oil recovery factor. The research results help to better analyze and screen the S/P system used for oil extraction and improve crude oil recovery.