Research on high pressure hydraulic slotting technology for pressure relief and permeability increase of coal seam

Abstract

High pressure hydraulic slotting technology is one of the technical means of pressure relief and permeability increase in high gas and low permeability coal seam area. Different coal seam conditions, the selected slotting process parameters are different. In order to obtain the reasonable parameters of high-pressure hydraulic cutting in soft coal seam, the field tests of different cutting pressure, different cutting time, different rotation speed and different cutting spacing were carried out in No.2 coal seam of Xue-hu Coal Mine. The test results show that the optimal cutting pressure is 60MPa ∼ 70MPa, the cutting speed is 80R / min, the cutting interval is 2m / knife, and the coal output of single knife is controlled at about 1.6T. Tests were carried out for different spacing of boreholes, the results show that the average extraction concentration of slotted hole is 1.75 times that of common hole, and the average extraction purity is 3.25 times that of common hole.