采空区瓦斯地面定向钻井抽采效果分析

Effects Analysis for Goaf Gas Extraction Using Ground Directional Drilling

为了解决井下工作面瓦斯超限的问题并提高采空区瓦斯抽采效果,采用理论分析与现场实测相结合的方法,通过分析整个回采过程中地面定向钻井抽采采空区瓦斯的浓度和纯流量随工作面推进距离的变化,研究了水平轨迹与采煤工作面回风巷交叉且竖直轨迹倾斜向下的地面定向钻井随井下工作面推进的瓦斯抽采效果。研究结果表明:当工作面推进至距切眼约600~810m时,地面定向钻井抽出的瓦斯浓度和纯流量均最高,分别为1135m^3/h和75.5%,并由此确定了瓦斯富集区所对应的最佳井位和层位。对地面定向钻井和地面垂直钻井等采空区瓦斯抽采技术井位层位的确定具有很大的指导意义。

In order to prevent the gas over-run in underground working face and improve goaf gas extraction effect,in this study,the theoretical analysis and field measurement are carried out,by analyzing the variation of the gas concentration and pure gas flow rate in the goaf gas extraction using ground directional drilling as the working face advances during the whole mining process,the extraction effect is studied when the drilling’s level trajectory intersects with the working face air return way and the vertical trajectory inclines downward.The results show that when the working face is advanced to about 600~810 m from the open-off cut,the gas concentration and pure flow rate of the ground directional drilling are the highest,which are 1135 m^3/h and 75.5%respectively,and thus the optimal well location and horizon of the gas enrichment zone corresponding is determined.The study results provide guidance for determining the optimal location and position of ground directional drillings,ground vertical drillings and so on.