Abstract: In response to the challenges of achieving balanced stimulation in the thin-interbedded, low-permeability reservoirs with large span in the Bohai Sea, this study establishes mechanical models for the migration and sealing of diverting balls to investigate the influence of different diverting parameters on their migration and sealing behavior. Based on discrete element theory, the method for controlling fluid flow distribution at fracture openings during diverting fracturing was developed. A three-dimensional model for fracture propagation during diverting fracturing was established to study the effects of different ball injection coefficients, diverting timing, and diverting frequency on multiple fracture propagation. The research indicates that: 1) The optimal pump rate for efficient seating of diverting balls is 4 m$^3$/min. 2) Diverting balls with low density and fracturing fluids with high viscosity enhance the plugging effect; when the ratio of diverting ball diameter to perforation diameter exceeds the critical plugging value of 1.6, the plugging effectiveness deteriorates. 3) Under the model parameters, the optimal ball injection coefficient ranges from 1.8 to 2.0, with 1 to 2 diverting operations, and employing mid or early-stage diverting operations significantly improves the uniformity of fracture propagation. Based on theoretical and numerical simulation studies, the post-fracturing production of Well H-2 was increased threefold, achieving a productivity of 100 m$^3$/d. This research provides theoretical guidance and technical reference for optimizing the parameters of diverting processes in offshore thin-interbedded sandstone reservoirs.

Key words: temporary plugging and flow-controlled fracturing, mechanical model of temporary plugging ball, non-uniform perforation, flow regulation, multi-fracture propagation