关键词: 低透气性, 高瓦斯, 煤层群, 千米定向钻孔, 瓦斯抽采

Abstract: In order to solve the problem of low-permeability and high-gas short-distance coal seam group mining, a large amount of pressure relief gas from adjacent coal strata poured into the working face, adopt the method of combining theoretical analysis and numerical simulation, the analysis of the working face roof fissure and the relationship between the pressure relief seam gas enrichment, to simulate the mining working face roof fracture distribution and evolution law, puts forward the directional drilling pump mining goaf roof km upper agglomeration of the technical scheme of pressure relief gas, and combined with the actual conditions of 14301 working surface, the technical parameters of directional drilling arrangement for roof kilometer are determined in this paper. Field application shows that during the observation period of gas extraction in the roof kilometer drilling field, the concentration of gas extraction is always more than 25%, and the highest is 80%. The pure amount of gas extraction is between 2.0m3/min, and the effective extraction concentration lasts for a long time, achieving good gas extraction effect.