Geology–Engineering-Integrated Differentiated Fracturing Design for Deep Shale Gas: Parameter Optimization and Effectiveness Evaluation

In recent years, the development of deep shale gas has recently become a challenge in the global shale revolution. Haynesille and other blocks in North America have achieved the efficient construction of complex fracture networks through optimized cluster spacing and temporary plugging techniques. However, factors such as complex geological conditions, highly natural fracture scales, and variable geostress states in the southern Sichuan Basin of China are significantly different from those found in homogeneous reservoirs. To address this, a scientific and systematic integrated evaluation method and parameter optimization technology are urgently needed to enhance reservoir transformation effectiveness and prevent the frequent occurrence of complex risks. This study selected the Luzhou deep shale gas block in the southern Sichuan Basin of China. A geological and engineering analysis of the region produced a “1 + 27” geological–engineering model classification system. Based on a fracture morphology inversion model derived from microseismic data, an optimal hydraulic fracture morphology template was created. Numerical simulations of hydraulic fractures under different nature fracture patterns were conducted using the ideal fracture length, height, and natural fracture influence to characterize the optimal fracture network and design parameters. Conducting big data analytics finally led to the establishment of a comprehensive fracturing effectiveness evaluation method and a fracturing parameter optimization matching template for deep shale gas wells. The results showed that under static high-quality reservoir conditions in the Luzhou deep shale gas block, large-scale unidirectional fractures significantly affected production and fracturing conditions. Measures such as high-intensity transformation in the matrix section, moderate scale control in the risk section, and avoiding fracturing near faults should be implemented. This innovative, single-stage, “form-based” effectiveness evaluation process enables comprehensive fracture network quality evaluation throughout pre-frac parameter assessment and mid-frac and post-frac production evaluation. However, the single-well “quantitative” evaluation method is more comprehensive in this study. To conclude, the established shale gas well-fracturing effectiveness evaluation and parameter optimization in this study will be upgraded with the update of monitoring methods, offering more effective technical ideas for fracturing technology and parameter optimization.