赵庄矿石门揭煤冲孔试验与钻孔优化布置研究

Experimental Study and Optimization Layout for Punching and Drilling of Cross-hole Coal Seam in Zhaozhuang Mine

为确保赵庄矿石门安全揭煤,决定采用水力冲孔技术对煤层进行卸压增透。针对现场冲孔钻孔平均出煤量较少高于1 t/m与抽采负压经验化的问题,采用数值模拟软件COMSOL对出煤量0.5、0.75、1 t/m以及不同抽采负压对钻孔瓦斯抽采效果的影响进行了模拟。模拟结果表明:预抽期180 d时,现场最佳布孔间距为出煤量1 t/m时的12 m,孔组对角区域的瓦斯抽采空白带消失;增大抽采负压对抽采效果影响有限。工程实践表明:水力冲孔后钻孔瓦斯抽采量是未冲孔前的5~10倍,瓦斯浓度较冲孔前提升3~6倍,冲孔后瓦斯浓度普遍保持在70%以上。

In order to ensure the safety of coal seam in Zhaozhuang coal mine,decided to adopt hydraulic piercing technology to relieve pressure and increase permeability of coal seam. In view of the problem that the average coal output is less than 1 t/m and pumping negative pressure, the numerical simulation software COMSOL is used to simulate the effect of coal output of 0.5,0.75,1 t/m and different extraction negative pressure on the drilling gas extraction effect. The simulation results show that the optimum spacing of the field distribution is 12 m when the amount of coal is 1 t/m,while the gas extraction blank zone in the diagonal area of the hole group disappears, and the negative pressure of the extraction production is limited to the extraction effect of the hole group in the pre pumping period of 180 d. The engineering practice shows that the gas extraction is 5 -10 times that of the unpunched hole, the gas concentration is 3-6 times higher than that before the punching hole, and the gas concentration after the punching is generally above 70%.