顶板岩层定向卸压瓦斯抽采钻孔钻进关键技术

顶板高位孔是治理采空区瓦斯的主要途径之一。在施工过程中，会遇到岩层开分支困难、目标层位的失制、非稳定地层处的纠偏等难题，它有别于煤层定向钻孔施工，阐述了顶板岩层定向卸压瓦斯钻孔施工的关键技术，对顶板定向长钻孔施工具有重要意义。 

The key technology for drilling pressure-releasing gas drainage hole in roof strata

High-level hole in roof is one of the major approaches to control the gas in gob. During drilling, problems such as difficulty of branching in stratum, out-of-control of the target horizon and rectifying deviation at unstable formation may be encountered. It is different from in-seam directional drilling. The paper elaborated the key technology for drilling of directional pressure-releasing gas drainage hole in roof formation. It has important significance for drilling long hole in roof.