In order to solve the problem of difficult gas extraction in coal mine, a method of gas extraction from coal seam by interval hydraulic flushing is put forward. Based on the coal seam gas occurrence conditions of 7609 working face in Wuyang Coal Mine, the numerical simulation research on gas drainage by ordinary drilling and hydraulic flushing drilling was carried out by using COMSOL numerical simulation software. The results show that with the increase of hydraulic flushing coal quantity, the effective gas drainage radius also increases. The effective extraction radius of ordinary drilling is 0.5 m, and the effective extraction radius is 1.0 m, 1.2 m and 1.3 m respectively when the coal flushing quantity is 0.5t/m, 1.0t/m and 1.5t/m. As multiple boreholes are drained at the same time, the boreholes will affect each other, which will reduce the gas pressure and increase the effective drainage radius, the spacing between boreholes can be greater than twice the effective drainage radius of a single borehole when arranging boreholes. And the smaller the flushing interval, the more uniform the gas pressure reduction area. According to the numerical simulation results, the ordinary drilling and 1.0t/m interval hydraulic flushing test were carried out in the field. Through observation and analysis, the gas concentration of the interval hydraulic flushing drilling module was increased by 31.2% and the drainage purity was increased by 5.77 times compared with the ordinary drilling module. It shows that the interval hydraulic flushing drilling can effectively improve the gas drainage effect.

为了解决煤矿瓦斯抽采困难的问题，提出了一种采用间歇水力冲洗从煤层抽采瓦斯的方法。根据舞阳煤矿7609工作面煤层瓦斯赋存条件，利用COMSOL数值模拟软件对普通钻井和水力冲洗钻井进行瓦斯抽采的数值模拟研究。结果表明，随着水力冲洗煤量的增加，有效瓦斯抽采半径也随之增加。普通钻进的有效抽采半径为0.5 m，当洗煤量为0.5t / m，1.0t / m和1.5t / m时，有效抽采半径分别为1.0 m，1.2 m和1.3 m。由于同时排放多个钻孔，因此钻孔会相互影响，这会降低气压并增加有效排水半径，在布置井眼时，井眼之间的间距可以大于单个井眼的有效排水半径的两倍。并且，冲洗间隔越小，则气体减压面积越均匀。根据数值模拟结果，在现场进行了常规钻井和1.0t / m间隔的水力冲洗试验。通过观察和分析，与常规钻井模块相比，间隔液压冲洗钻井模块的瓦斯浓度提高了31.2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。布置井眼时，井眼之间的间距可以大于单个井眼的有效排水半径的两倍。并且，冲洗间隔越小，则气体减压面积越均匀。根据数值模拟结果，在现场进行了常规钻井和1.0t / m间隔的水力冲洗试验。通过观察和分析，与常规钻井模块相比，间隔液压冲洗钻井模块的瓦斯浓度提高了31.2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。布置井眼时，井眼之间的间距可以大于单个井眼的有效排水半径的两倍。并且，冲洗间隔越小，则气体减压面积越均匀。根据数值模拟结果，在现场进行了常规钻井和1.0t / m间隔的水力冲洗试验。通过观察和分析，与常规钻井模块相比，间隔液压冲洗钻井模块的瓦斯浓度提高了31.2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。气体减压区域越均匀。根据数值模拟结果，在现场进行了常规钻井和1.0t / m间隔的水力冲洗试验。通过观察和分析，与常规钻井模块相比，间隔液压冲洗钻井模块的瓦斯浓度提高了31.2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。气体减压区域越均匀。根据数值模拟结果，在现场进行了常规钻井和1.0t / m间隔的水力冲洗试验。通过观察和分析，与常规钻井模块相比，间隔液压冲洗钻井模块的瓦斯浓度提高了31.2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。与普通钻探模块相比，排水效率提高了2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。与普通钻探模块相比，排水效率提高了2％，排水纯度提高了5.77倍。结果表明，分段水力冲洗能有效提高瓦斯抽采效果。