定向拦截钻孔技术在近距离煤层开采中的研究与应用

Research and Application of Directional Intercept Drilling Technology in Close Range Coal Seam Mining

平煤八矿己15煤层和下伏己16.17煤层间距8~10 m,属于近距离煤层;己15煤层回采期间,受采动影响,己16.17煤层卸压瓦斯越流逸散,造成回采工作面瓦斯含量增加。以己15-15050工作面为试验点,在工作面中间低位巷采用“定向拦截钻孔+全程下筛管”技术,将拦截钻孔施工至工作面中部瓦斯抽采薄弱带、两层煤之间常规钻孔不易施工到的岩柱内,探究定向拦截钻孔抽采效果。结果表明:实际施工的48个定向拦截钻孔,按照设计施工至准确层位的成功率为94%,筛管覆盖率达到91%;定向拦截钻孔在工作面切眼前后60 m范围内,单孔抽采浓度在60%~99%;与常规拦截钻孔相比,定向拦截钻孔的最高单孔瓦斯抽采浓度可以提高48%~59%。

The distance between VI 15 coal seam and underlying VI 16.17 coal seam in Pingmei No.8 coal mine is 8-10 m,belonging to a close range coal seam;during the mining of VI 15 coal seam,due to the impact of mining,the pressure relief gas in VI 16.17 coal seam flowed and dispersed,resulting in an increase in the gas content in the mining face.Taking the VI 15-15050 working face as the test point,the technology of"directional intercepting drilling+loading the screen pipe in the whole hole"was adopted in the low-level roadway in the middle of the working face,the intercepting drilling was constructed into the weak zone of gas drainage in the middle of the working face,and the rock pillar between two layers of coal was not easily constructed byconventional drilling,to explore the drainage effect of directional intercepting drilling.The results show that for the 48 directional interception boreholes actually constructed,the success rate of constructing to the accurate layer according to the design is 94%,and the screen pipe coverage rate reaches 91%;the directional interception drilling hole is within 60 m behind the cutting face,and the single hole extraction concentration is between 60%and 99%;compared with conventional interception boreholes,the maximum single hole gas extraction concentration of directional interception boreholes can be increased by 48%to 59%.