Study On Gas Pre-extraction Technology For Large Diameter And Long Borehole In Xinyuan Mine

Yangquan mining area is a typical mining area with high gas content,low permeability and development of crushed soft coal seam.It is very difficult to extract gas with conventional methods,which is mainly reflected in two aspects.First,it is easy to collapse holes in the process of drilling,which makes it difficult to form holes and lacks corresponding drilling technology.Second,due to the low permeability of crushed soft coal seam,gas extraction is very difficult,the lack of the corresponding effective anti-reflection technology.Based on the project background of 9108 working face of xinyuan mine,this paper develops the drilling technology of large diameter bedding long hole in large diameter coal seam with soft crushing and low penetration outburst.Introduced EH260 type hydraulic rotary drill rig is realized by using even the crawler since the shifter to mobile equipment,USES the drill pipe hydraulic clamping device can improve the drill pipe joint in accuracy,reduces the drill pipe joint in time,the series stabilizer to avoid serious tool deflection,structure innovation and technology to improve drilling rig drilling efficiency of coal seam by 100%,complete aperture of127 mm,length 260 m along coal seam in directional drilling,the progressive realization of the 240 m long face protected zone gas gas control technology,a cover layer and extraction of excavating in coal roadway protection section(unloading)the purpose of the gas.Compared with the original gas treatment measures,the pre-extraction borehole in the single-wing bedding section can effectively reduce the outburst risk of coal roadway driving and improve the pre-extraction rate of borehole,and realize the co-extraction of coal and gas.The maximum speed of face progressive shield tunneling is increased from 110m/ month to 270m/ month,and the average is increased from 90m/ month to 160m/ month.During the tunneling period,the gas desorption index of drill cuttings and the effective test of drill cuttings did not exceed the standard,which achieved the effect of rapid tunneling under progressive screen of the coal seam along the seam length with the low-penetration outburst of crushed soft.