Optimization of segmented fracturing parameters for coalbed methane horizontal wells based on comprehensive fracability index

The coal seams in the Shizhuang block of the Qinshui Basin are characterized by developed cleats, low permeability, soft coal structures, and strong heterogeneity. In earlier development stages, hydraulic segmented fracturing of horizontal wells resulted in significant variations in gas production per well, with unclear relationships between gas well productivity and fracturing parameters. This led to poor economic performance in coalbed methane（CBM） development, highlighting the need for optimization of horizontal well fracturing parameters. This study established a comprehensive fracability index（CFI） evaluation model based on coal seam brittleness, in-situ stress, and reservoir-seepage characteristics. Considering the impact of stress shadows during horizontal well fracturing, stress shadow and fracture interference charts were generated for different coal seam structures, clarifying the effects of net pressure, fracture length, spacing, and cluster number on induced stress. Based on the economic requirements for CBM development, the fracturing positions and segment design parameters of horizontal wells with different CFI values were optimized by considering the relationship between the internal rate of return (IRR) of single-well investment and daily gas production. A high-efficiency fracturing technology chart for horizontal wells was developed, aimed at improving the fracturing effectiveness in the Shizhuang block of Qinshui Basin and enhancing the quality and efficiency of CBM exploration and development.