Study on Composite Profile Control Based on Time-Varying Reservoir Characteristics and Flow Field Simulation

Addressing the issues of low water flooding efficiency and severe invalid cycling in oil-water wells in high-water-cut oilfields, this study proposes a composite profile control and flooding method based on time-varying reservoir characteristics and flow field simulation, aiming to improve water flooding sweep efficiency. Main and secondary water channel identification was conducted using water passing multiple and streamline tracking technology. A four-level composite profile control system (Pre-slug - Plugging slug - Profile control and flooding slug - End sealing slug) was designed, incorporating the properties of gel and Preformed Particle Gel (PPG). A numerical model for profile control was established based on time-varying reservoir characteristics, considering the synergistic effects of gel and PPG. The effectiveness of the profile control was comprehensively evaluated. Numerical simulation results indicate that the gel diffusion range is 120–150 m, and the PPG diffusion range is 160–180 m, effectively covering the predicted water channels. After the treatment, the high-density streamline directionality is significantly improved, the plugging slug substantially reduces the main water channels, and the profile control and flooding slug further improves the secondary water channels. The oil saturation in the weak swept zones decreases by 5%-8%, and the water flooding sweep range is significantly expanded. This study applies a composite profile control system, leveraging the synergy between gel and PPG, providing a novel approach for profile control in high-water-cut reservoirs.