Study on the Application and Performance of High-Temperature-Resistant Copolymer Gel in Plugging Fracture-Induced Water Channeling Pathways

Abstract During heavy oil thermal recovery processes, hydraulic fracturing is an effective method for optimizing steam injection efficiency. However, the fractures created by the fracturing operation may connect with high-water saturation zones, forming high-temperature fracture-induced water channeling pathways. This not only increases water production in the wells but also significantly reduces oil and gas production, negatively affecting development efficiency. Gel-based plugging agents are commonly employed to effectively block these water channeling pathways. However, traditional polymer gels exhibit instability under high-temperature conditions, resulting in leakage and diminished plugging performance. In this study, a high-temperature-resistant copolymer gel suitable for 150°C environments was developed, and its gelation performance, thermal stability, and plugging effectiveness were systematically evaluated. The experimental results indicate that the gelation time of the copolymer gel at 150°C is 10 hours, with the post-gelation viscosity reaching 3483 mPa·s. After 30 days of aging at 150°C, the gel maintained a high viscosity, and its micro-network structure remained stable at approximately 100 μm. In core fracture plugging experiments, the plugging efficiency reached 96.2%. Furthermore, numerical simulations of heavy oil thermal recovery fracture plugging, based on laboratory experimental data, further validated the excellent plugging performance of the copolymer gel under high-temperature conditions. The gel effectively plugs fracture-induced water channeling pathways, reduces the water cut at the production well, and increases oil and gas production, providing strong technical support for the efficient development of heavy oil thermal recovery.