工作面煤层瓦斯立体抽采时空效应分析

Analysis of spatial and temporal effects of three-dimensional gas drainage from coal seams in working faces

针对低透气性煤层瓦斯难以抽采的问题,以新集二矿220112工作面回采区域煤层为背景,采用倾向顺层钻孔、底板穿层钻孔、顶板定向钻孔及上隅角埋管抽采相结合的立体瓦斯抽采系统抽采瓦斯。瓦斯抽采数据表明,回采煤层瓦斯抽采具有一定的时间效应和空间效应,抽采瓦斯的混合量和瓦斯浓度随着抽采时间和推进距离的增加呈现减小趋势,并趋于稳定;上隅角埋管和高抽巷抽采瓦斯浓度和混合量与顶板周期来压具有较好的一致性,上隅角埋管抽采瓦斯受周期来压影响较大,在周期来压前,应加强上隅角瓦斯抽采,防止周期来压时上隅角瓦斯超限。抽采效果表明,工作面回采区域瓦斯预抽率为31.9%,实测最大残余瓦斯含量为3.5 m^(3)/t,最大残余瓦斯压力0.25 MPa,回采期间钻屑瓦斯解吸指标最大值为90 Pa,钻屑量最大值为2.6 kg/m,取得了较好的抽采效果,实现了回采工作面的安全开采。

In view of the difficulty of gas drainage in low-permeability coal seam,taking the mining area coal seam of No.220112 working face of of Xinji Second Coal Mine as background,a three-dimensional gas drainage system combining inclined bedding drilling,floor through layer drilling,roof directional drilling and upper corner buried pipe drainage was adopted to extract gas.The data of gas drainage show that the gas drainage of mining coal seam has a certain spatial effect and space effect,and the mixture amount of gas drainage and concentration of gas decrease and tend to be stable with the increase of drainage time and distance.The concentration and mixing amount of gas drainage by buried pipes and high drainage roadways in the upper corner have good consistency with the cyclic pressure of the roof.The gas drainage by buried pipes in the upper corner is greatly affected by cyclic pressure.Before cyclic pressure,it is necessary to strengthen the gas drainage in the upper corner to prevent the gas from exceeding the limit during cyclic pressure.The drainage results showed that the gas pre-drainage rate in the mining area of working face was 31.9%,the measured maximum residual gas content was 3.5 m^(3)/t,the maximum residual gas pressure was 0.25 MPa,the maximum value of gas desorption index of drilling cuttings was 90 Pa,the maximum value of drilling cuttings was 2.6 kg/m,and a good drainage effect was achieved,the safety mining of the mining face was realized.