Hydrocarbon Displacement Efficiency by Water and Polymer and Optimization of Multiple Parameters in Porous Media: Experiments and Numerical Simulation

Polymers are effective agents for EOR due to their water solubility, which improves water viscosity, sweep volume, and displacement efficiency. To elucidate their mechanisms in EOR and optimize polymer–water synergistic flooding parameters, this study combined core and core network experimental research with numerical simulations. Experimental flooding results demonstrated that polymer–water synergistic flooding reduces residual oil saturation by 13.79% compared to water flooding. Key parameters such as well pattern, well spacing, bottom-hole pressure, polymer viscosity, and injection slug size were optimized through numerical simulation of a conceptual model based on actual oilfield data. A bottom-hole flowing pressure of 10.6 MPa, well pattern density of 84 wells/km², staggered line drive pattern, and polymer viscosity of 21 cp are recommended for EOR. Numerical simulation data showed that polymer–water synergistic flooding enhances displacement efficiency by 5–11% over conventional water flooding. The findings from the experimental research and numerical simulations indicate that the total recovery factor may be increased by implementing the recommended parameters in an actual oilfield.