In order to solve the problem of much gas occurrence in soft coal seam and poor permeability of coal seam.The pressure relief and permeability enhancement technology of directional water jet in cross-layer drilling was studied by means of numerical simulation and field tests.Combined with the actual conditions of Wuyang Coal Mine and the numerical simulation results.The optimum parameters of directional water jet cavitation process are as follows:roof cavitation with cavitation thickness of 0.4 m,cavitation radius of 0.8 m,and borehole spacing of 5 m.The field test results of the cross-layer directional water jet equipment show that the improved equipment can realize the soft stratification cavitation of the coal seam.Compared with the conventional drilling gas extraction process,the daily gas extraction concentration of the roof directional water jet cavitation process is increased by about 30 percentages on average.The directional water jet permeability enhancement technology at the top of the coal seam can effectively improve the overall pressure relief effect of the coal seam and improve the efficiency of borehole gas extraction.
关键词
定向水射流/卸压增透/数值模拟/顶板造穴/瓦斯抽采
Key words
Directional water jet/Pressure relief and permeability enhancement/Numerical simulation/Roof cavitation/Gas extraction
维普
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