近距离煤层群拦截钻孔瓦斯抽采技术研究

Research on Gas Extraction Technology of Interception Boreholes in Close-Distance Coal Seam Groups

针对近距离煤层群瓦斯治理难题,以杜儿坪煤矿某工作面为研究对象,模拟开采后覆岩裂隙发育情况。根据近距离煤层群瓦斯抽采机理,利用FLUENT软件模拟采空区在布置顶板高位钻孔前后和“顶板高位+底板拦截”钻孔后的瓦斯运移情况,对比分析抽采效果和工作面上隅角CH_(4)体积分数。结果表明:覆岩垮落带高度为16m,裂隙带高度为58m;将顶板高位钻孔布置在垂直位置距顶板38.5~57.25 m,水平位置距回风巷20~50m范围内,底板拦截钻孔布置在距底板正下方5m,距回风巷侧10~15m时,工作面上隅角的CH4体积分数降低至0.32%,瓦斯抽采效率高;对工作面采空区高位定向钻孔联合底板拦截钻孔技术进行现场应用,取得了良好的瓦斯治理和抽采效果。

Aiming at the problem of gas control in close-distance coal seam group,taking a working face of Du'erping Coal Mine as the research object,the development of overburden fracture after mining was simulated.According to the gas extraction mechanism of close-distance coal seam group,FLUENT software was used to simulate the gas migration in goaf before and after the arrangement of high-level roof boreholes and after the“roof high-level and floor interception”boreholes.The extraction effects and the volume fractions of CH_(4) in the upper corner of the working face were compared and analyzed.The results show that the height of overburden caving zone is 16 m,and the height of fracture zone is 58 m.When the roof highlevel boreholes are arranged in the vertical distance of 38.5-57.25 m from the roof,the horizontal position is within the range of 20-50 m from the return air roadway.And when the floor interception boreholes are arranged 5 m below the floor and 10-15 m from the side of the return air roadway,the CHa volume fraction in the upper corner of the working face is reduced to O.32%,with an improved gas extraction efficiency.The field application of roof high-level directional borehole combined with floor interception borehole technology in goaf of working face has achieved a good gas control and extraction effect.