Application of hydraulic fracturing technology in low-permeability coal seams at Heilianghe Coal Mine

Aiming at the low permeability of the No. 15 coal seam in the Heilianghe mining area and the difficulty in controlling gas enrichment zones, horizontal five-hole and cross five-hole layout schemes were constructed. RFPA2D-flow numerical simulation was used to conduct fluid-solid coupling analysis of hydraulic fracturing, revealing the evolution law of fracture networks under multi-hole synergistic fracturing. Based on parameter sensitivity analysis, the optimal hole layout scheme was selected and the water injection pressure threshold was determined. Engineering verification was carried out at the 1205 fully mechanized mining face of the No. 15 coal seam. The results show that the introduction of the dynamic equilibrium mechanism of in-situ stress effectively improved the model reliability. By arranging drainage holes within the 3 m radius of the fracturing influential zone, the extraction concentration can achieve a gradient increase from 34.4% to 61.3%, significantly reducing the risk of rock burst.