Research on fracture propagation patterns and stress field evolution during integrated fracturing of platform wells

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To address the complexities of stress field dynamics and fracture propagation mechanisms during multi-well platform fracturing in unconventional reservoirs, this study establishes a three-dimensional (3D) geomechanical and multi-physical field coupling model under an integrated geoengineering framework. The model elucidates stress interference mechanisms and fracture network formation patterns under multi-well coordinated fracturing. A high-resolution 3D geological model, constructed using the Petrel platform, was employed to simulate the zipper fracturing process of 19 horizontal wells across three platforms (Nos. 61, 62, and 63) in the Jimusar shale oil reservoir. By integrating the boundary element method with fracture mechanics theory, the research quantifies the effects of legacy well-fracturing and ongoing production on in situ stress reorientation (maximum deflection angle: 75°) and fracture propagation in new wells. Results demonstrate that pore pressure depletion and stress direction deflection significantly alter fracture trajectories in new wells, reducing fracture network connectivity and leading to a 19.92% decline in cumulative oil production for new wells adjacent to legacy wells. Orthogonal optimization experiments identified displacement rate (17 m3/min) and cluster density per stage (7 clusters) as critical parameters for productivity enhancement. The optimized solution (A3B3C1D2E4) achieved a 9.7% increase in 6-year cumulative oil production compared to the baseline. Leveraging four-dimensional (4D) geomechanical inversion and intelligent parameter optimization, this work provides a theoretical foundation and operational strategies for multi-platform collaborative fracturing, advancing the efficient development of complex unconventional reservoirs.