煤层钻孔瓦斯渗流特性研究

Research on Gas Seepage Characteristics of Coal Seam Drilling

针对阳泉新宇岩土工程有限责任公司Ⅱ7_(2)24S工作面7_(2)煤层瓦斯抽采问题,建立穿层钻孔抽采瓦斯三维几何模型,研究分析钻孔抽采方案中孔周围瓦斯渗流特征,煤层应力分布特点、渗透率变化情况、钻孔有效抽采半径,结合孔群联合抽采方式和抽采叠加效应的影响,合理规划抽采钻孔的孔距,对采空区及煤矿巷道附近的瓦斯排放带宽度进行研究,仿真结果表明采空区及煤矿巷道附近的瓦斯排放带宽度分别为22.3 m、28.1 m。结果表明:钻孔抽采30 d有效半径为0.87 m,90 d有效半径为1.5 m;实际测得巷道周围瓦斯排放带宽度为25 m宽,采空区周围瓦斯排放带宽度为30 m宽,与模拟结果接近。

In view of the gas extraction problem in the 7_(2) coal seam of theⅡ7_(2)24S working face of Yangquan Xinyu Geotechnical Engineering Co.,Ltd.,a 3D geometric model of gas extraction through layered drilling is established.The gas seepage characteristics around the holes,the distribution characteristics of coal seam stress,permeability changes situation,and the effective extraction radius of the drilling holes in the drilling and extraction scheme are studied and analyzed.Combined with the joint extraction method of the hole group and the impact of the extraction superposition effect,the hole spacing of the extraction drilling is reasonably planned.The width of the gas emission zone near the goaf and coal mine roadway is studied.The simulation results show that the width of the gas emission zone near the goaf and coal mine roadway is 22.3 m and 28.1 m,respectively.The results show that the effective radius for drilling and extraction is 0.87 m for 30 days,and 1.5 m for 90 days;The actual measured width of the gas emission zone around the roadway is 25 m,and the width of the gas emission zone around the goaf is 30 m,which is close to the simulation results.