Abstract:
                                      The 13-1 coal seam in Zhujidong Coal Mine exhibits high gas pressure and gigh gas content, belonging to the outburst coal seam. In order to eliminate the danger of outburst and ensure the safe and efficient mining of the coal seam, this study proposes employing surface well staged hydraulic fracturing technology to induce fractures in the coal seam. This process involves perforation and hydraulic fracturing along the wellbore trajectory to release pressure and increase permeability in each coal and rock layer. Following the strategy of segmented and clustered optimization and adopting different pumping strategies for each fracturing section, the principle of " large volume, large particle size, and high sand concentration" was utilized to regulate fluid volume and improve sand support effectiveness in each fracturing section. The actual injection of fracturing fluid and the amount of sand added were significantly higher than the designed parameters. Moreover, the four-dimensional image monitoring of fracturing fractures by intensive array energy scanning revealed that the total volume of hydraulic fracturing fractures in each section could reach 1061. 93 m
3, and the daily gas yield during the stable gas production stage could exceed 2,500 m
3. These findings demonstrate that surface well staged hydraulic fracturing technology is highly applicable for increasing permeability within the 13-1 coal seam by promoting intersection and penetration of fracture zones. Better cracking and permeability increase effect and gas drainage efficiency could provide safety guarantee for the safety of coal seam mining.