低渗煤层超高压水射流不同割缝间距的力学特征

Mechanical characteristics of different slotting spacing of ultra-high pressure water jet in low permeability coal seam

为了解决孟村煤矿低透气性煤层卸压效果差、抽采效率低的难题,以孟村煤矿4号煤层低渗煤层深钻孔为研究对象,采用煤层超高压水力割缝技术进行瓦斯抽采。通过COMSOL Multipysics 5.4多物理场软件分析不同割缝间距条件下超高压水力割缝工艺参数的抽采效果,使割缝钻孔达到最大抽采效率。结果表明,一定条件下,割缝间距越大,煤体卸压范围越小,瓦斯压力变化范围越小,煤体渗透率变化范围越小;综合考虑设备性能及经济性设计割缝间距参数为6 m;工艺技术参数的选择对煤层深孔卸压增透技术的应用具有一定现实指导意义。

In order to solve the problems of poor pressure relief effect and low extraction efficiency in low permeability coal seams of Mengcun Coal Mine,taking No.4 coal seam with low permeability in Mengcun Coal Mine as the research object,ultra-high pressure hydraulic slotting technology is used in the coal seam to improve gas extraction efficiency.Using COMSOL Multipysics 5.4 multi-physical field software,the gas extraction effect of ultra-high pressure hydraulic slotting parameters under different slotting spacing is analyzed,so as to achieve the maximum extraction efficiency.The results show that under certain conditions,the larger the slotting spacing,the smaller the pressure relief range of coal,and the smaller the variation range of gas pressure and coal permeability.Considering the equipment performance and cost,the slotting spacing is designed as 6 m.The selection of technological parameters has certain practical guiding significance for the application of deep borehole pressure relief and permeability enhancement technology in coal seam.