Study on optimization of process parameters of ultra-high pressure hydraulic slotting for permeability enhancement in coal seam
Aiming at the problems of large flow resistance and difficulty of gas extraction in coal seam of a coal mine in China,an experi-mental method was used to optimize the process parameters of ultra-high pressure hydraulic slotting and permeability enhancement in the A32 working face of No.3001 coal seam,and the influence of process parameters on gas extraction effect was studied by the control vari-able method.The results show that the permeability enhancement effect is best when the slotting time is 40 min,the slotting spacing is 3 m,the slotting pressure is 50 MPa,and the drill pipe slotting rotation speed is 70 r/min.Meanwhile,through the comparison of drilling technology in the same coal seam,the optimized high pressure hydraulic slotting process parameters are used to enhance the permeabili-ty,under the condition of the same number of slotting and drilling,the average gas extraction is twice that of traditional drilling,and the average coal output is increased by about 45%,with remarkable effect.
ultra-high pressuregas extractionprocess parameter optimizationhydraulic slottingpressure relief and permeability en-hancement