瓦斯抽采钻孔水射流协同修护技术研究与应用

Research and application of water jet and cooperative repair technology in gas drainage

瓦斯抽采钻孔普遍存在因变形、煤渣积聚及塌孔等导致钻孔堵塞和抽采效果差的问题。通过分析钻孔塌堵失稳机制,得出煤岩体性质、地质构造及多应力耦合条件是造成钻孔失稳的主要因素,进而推断相应堵孔段情形。利用高压水射流解堵作用,提出了水射流疏通-筛管护孔协同修护技术,并研制出轻型气动钻孔修复装备。应用结果表明,该协同修护技术能有效解决瓦斯抽采钻孔塌堵后无法有效抽采的技术难题,试验钻孔修护深度达到50 m,修护完成后单孔抽采瓦斯浓度和瓦斯纯流量比修复前提高0.57~3.67倍和0.99~5.15倍,抽采效果大幅改善,实现了塌堵钻孔的快速便捷修复进而确保了瓦斯流动通道的畅通。

Gas drainage boreholes generally have the problems such as blockage and poor drainage effects due to deformation,cinder accumulation,and borehole collapse.By analyzing the mechanism of borehole collapse instability,it was concluded that the properties of coal and rock mass,geological structure and multi-stress coupling condition were the main factors causing borehole instability,and then the situation of the corresponding blocked borehole section was deduced.By the action of high pressure water jet to solve the blockage,this paper put forward the technology of water jet dredging and screen pipe borehole collaborative repair,and a lightweight pneumatic drilling repair equipment was developed.The application results show that the cooperative repair technology can effectively solve the technical problem that the gas extraction borehole can’t be effectively extracted after drainage borehole collapses,the test borehole repair depth reaches 50 m,after repair,the concentration and pure flow of gas in single borehole extraction increased by 0.57 times to 3.67 times and 0.99 times to 5.15 times compared with that before repair,the drainage effect has been greatly improved,the quick and convenient repair of the collapsed and blocked borehole is realized to ensure the smooth gas flow channel.