Anti-permeability Technology of Cross-layer High Pressure Hydraulic Fracturing in Soft Coal Seam

To solve the low permeability of soft coal seams gas management existence question, 2124-3 a mine in Liupanshui coal face as the background, puts forward the use of secondary grouting hole sealing auxiliary hydraulic fracturing anti-reflection layer of high voltage technology, was studied by numerical simulation and field test under the action of high-pressure hydraulic fracturing fracture field dynamic evolution rule and unloading anti-reflection effect. The results show that the fatigue failure of the coal body can be caused by high-pressure hydraulic fracturing, so as to dredge pores and improve gas permeability. The effective anti-reflection radius is up to 30 m, which significantly improves the extraction concentration and flow rate of the drilling hole, shortens the extraction time to reach the standard, reduces the dynamic phenomena such as the index exceeding the standard and the spray hole in the anti-penetration construction, and reduces the gas concentration and the number of gas overrun in the tunneling process. This technology can effectively increase the influence range of a single hole, improve extraction efficiency, and has a wide application prospect.