Study on Temporary Plugging Agents and Process Simulation for Offshore Low-permeability Reservoirs Fracturing

Abstract Temporary plugging fracturing technology is an effective method for extending the range of segmented fracturing in horizontal wells and improving the utilization between fractures in low-permeability reservoirs. In this study, a controllable degradable temporary plugging agent was synthesized by graft copolymerization of PGA and PLA with a material ratio of 3:1, under the catalysis of stannous octoate at 150°C. This approach allows for controlled degradation of the temporary plugging materials by protecting PLA, which has good affinity to water, and adjusting the molecular weight of the product. It reduces the initial degradation rate while increasing the later degradation rate. To consider the heterogeneity of natural fractures and reservoir physical permeability in shallow sea reservoirs, a numerical model for temporary plugging and fracturing of horizontal wells was developed. The model investigates the influence of parameters such as displacement and cluster spacing on crack propagation, resulting in the formation of a simulation method suitable for temporary plugging fracturing of horizontal wells in heterogeneous reservoirs. The research findings indicate that crack length and width gradually increase with the increase of displacement. The maximum crack spread area is achieved at a displacement of 5~8m 3 /min. Temporary plugging can be implemented when the cluster spacing is ≤12m, allowing for the full expansion of cracks that have not effectively expanded. The largest crack spread area is observed at a crack spacing of 5~8m.