Application and effect analysis of ultra-high pressure hydraulic slotting precise control technology

Due to the improper selection of hydraulic slotting pressure, nozzle size, slotting time and other parameters, the slot depth of coal seam is shallow, the effect of pressure relived and permeability enhanced after slotting is not ideal, and the borehole is hold and blocked during slotting operation. In order to solve these problems, the ultra-high pressure hydraulic slotting precise control technology was proposed, slot width, depth control, speed control of slotted coal and effect control of slot area were analyzed, ZGF-100 (A) ultra-high pressure hydraulic slotting device was developed and the field application test of precise control slotting was carried out. The results show that as the precise control technology of the ultra-high pressure hydraulic slotting is adopted, the equivalent radius of the slot is about 1.02 m to 1.58 m, the average gas extraction purity of the slotted borehole is about 2 times larger than that of the ordinary borehole, the extraction radius of the slotted borehole is about 1 times larger than that of the contrasted hole.