Study on the application of ultra-high pressure hydraulic slotting in low permeability coal seam

Abstract In view of the difficulty in solving the problem of coalbed methane drainage and mining connection in Wangpo coal mine, a new layout method of slotted hole and common hole is put forward by adopting the ultra-high pressure hydraulic slotting technology and combining with the characteristics of coal seam. The drilling construction technology and construction process are optimized. The amount of coal discharged by slotted hole is statistically analyzed, and the gas drainage concentration and extraction of common hole in slotted hole are investigated. The results show that the ultra-high pressure hydraulic slotting radius is 1.60m ∼ 2.26m, the average gas extraction concentration of slotted borehole is 54.88%, the pure gas extraction of slotted borehole is 51.4% higher than that of ordinary borehole, and the time of reaching the standard is 37.5% ∼ 50%. Therefore, the ultra-high pressure hydraulic slotting technology can better solve the problem of increasing permeability of low permeability coal seam, and provide a new way for the prevention and control of coal mine gas disaster.