Optimization of Fracture Parameters and Turning Angle of Temporary Plugging Refracturing in the Triassic Chang 6 Reservoir

The Triassic Chang 6 reservoir in the Suijing Oilfield is characterized by poor reservoir quality, pronounced heterogeneity, well-developed fractures, and suboptimal well pattern configuration, which collectively impede the establishment of an efficient displacement system. During the initial development phase, low production rates and delayed lateral response were observed, prompting a tight-spacing infill drilling pilot in the central low-productivity zone. However, conventional fracturing with upscaled stimulation volumes yielded limited fluid production uplift, rapid water cut escalation, and marginal incremental oil recovery. To address these challenges, a dual strategy integrating legacy fracture modification and new fracture generation was developed. Key fracturing parameters influencing reservoir drainage efficiency were systematically investigated, and an orthogonal experimental design was employed to optimize these parameters. The following conclusions were drawn: Stimulation timing should be postponed until water cut stabilizes below 20% in high-productivity zones; the optimal fracture half-length was determined to be 190 m; post-fracturing conductivity was optimized to 30 μm2·cm; and the turning angle for corner wells was set at 23°. For low-productivity zones with impaired reservoir properties that lead to retarded waterfront advancement, refracturing is recommended to be deferred until the water cut reaches 20–40%. The findings of this study provide a theoretical foundation for optimizing on-site refracturing processes and offer valuable guidance for addressing the optimization of fracturing parameters in low-permeability tight sandstone reservoirs.