突出煤层深孔水力致裂驱赶与浅孔抽采消突研究

Study of coal seam outburst mitigation by deep hole hydro-fracturing and shallow hole methane drainage

通过三角形布置水力致裂钻孔、互为卸压孔和观测孔、深封孔短封孔长度等保障了突出煤层掘进头超前深孔水力致裂驱赶的安全性.采用现场试验观测了水力致裂的裂缝扩展与瓦斯驱赶范围,分析了水力致裂前后突出危险性指标、打钻难易程度、迎头瓦斯体积分数、瓦斯抽采效果和消突效果的变化.在水力致裂导致的孔隙水压力和瓦斯驱赶作用下,水力致裂结束后立即钻区域抽采孔较困难;4h后打钻就非常容易,很少出现吸钻、喷孔、煤炮声等现象.薛湖矿4条煤巷掘进的实践表明该技术区域消除了突出危险性.突出煤层掘进节省了10个区域孔的工程量和施工时间,区域消突瓦斯抽采时间减少8.3h以上.

The implementation of triangular drilling-hole arrangement for hydro-fracturing with alternating pressure relief hole and observation hole, as well as the correction selection of deep hole sealing position and short hole sealing length, ensures the safety of hydraulic fracturing in development heading in outburst prone coal seam. The scope of fracture propagation and meth- ane driving induced by hydraulic fracturing was observed in field experiment. The changes of outburst indicators, drilling difficulty degree, methane volume fraction in excavation heading, methane drainage effect and outburst elimination impact were analyzed before and after hydro- fracturing. Under the influence of pore water pressure caused by hydraulic fracturing and methane driving, it is difficult to drilling gas drainage holes immediately after hydraulic fractu- ring. However, it becomes much easy in 4 hours after hydro-fracturing and the phenomena of drill sucking, drilling-hole spurting and coal booming rarely appears. During the excavation of 4 tunnels in a outburst coal seam at Xuehu colliery, the technology has been proved to be a safe, effective and economical method to eliminate regional outburst risk. An equivalent time and engineering work for 10 drilling boreholes in each regional areas were saved. The gas drainage lead time for eliminating the regional outburst reduces by more than 8.3 hours.