改善松软煤层抽采孔砂岩孔壁力学行为研究

    Study on improving mechanical behavior of sandstone hole wall in soft coal seam

    • 摘要: 为了探究高温条件下,深部煤层瓦斯抽采钻孔孔壁砂岩力学行为和提高瓦斯抽采效率,以恒大煤矿1366工作面穿层瓦斯抽采钻孔岩孔段砂岩为研究对象,进行不同温度处理下砂岩的三轴压缩试验和不同载荷流变-渗透试验及应用膨胀水泥浆技术钻孔抽采试验。试验结果表明:高温导致试样裂隙发育,极限抵抗强度降低,结构膨胀,裂隙面积增大,渗透性增大,岩孔段残存瓦斯含量增大;膨胀水泥浆充砂岩裂隙,增强了抗塌保护层,缩小了瓦斯残余区,提高了煤层瓦斯抽采体积分数。

       

      Abstract: In order to study the mechanical behavior of sandstone on the wall of gas drainage borehole in deep coal seam under high temperature conditions and improve the efficiency of gas drainage, this article takes the sandstone in the rock hole section of the cross-seam gas drainage drilling hole in 1366 working face of Hengda Coal Mine as the research object, carring out triaxial compression test of sandstone under different temperature treatments, rheology-permeability test under different loads and drainage test of boreholes with expansive cement slurry. The test results show that the high temperature leads to the development of cracks in the specimen, the reduction of ultimate resistance strength, the expansion of structure, the increase of crack area and permeability, and the increase of residual gas content in rock hole section. The expansion cement slurry fills the cracks of sandstone, strengthens the anti-collapse protective layer, reduces the gas residual area, improves the gas drainage volume fraction of coal seam.

       

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