开闭式反循环钻头的结构设计与工作原理

由于煤层松软和破碎的缘故，松软突出煤层瓦斯抽放孔易垮塌，将导致钻孔成孔率低，瓦斯抽放通道易堵塞，影响了瓦斯抽采效率。为解决这些问题，设计了开闭式反循环钻头，并对其结构特点和工作原理进行分析。这种钻头结合了全程筛管下放和反循环钻进2种工艺的优势。通过降低对孔壁的二次破坏，提高了钻孔成孔率和成孔深度；通过全孔段下放筛管，防止孔壁垮塌堵塞瓦斯通道，提高了瓦斯抽放孔的利用率。介绍了该新型钻头的结构设计、工作原理和应用情况。

Configuration Design and Working Principles of Open-closed Reverse Circulation Bit

Due to the soft and broken characteristics of soft and outburst coal seam, the gas drainage borehole easily collapses with low borehole completion rate and the blockage of gas drainage channel, which influence the efficiency of gas extraction. The open-closed reverse circulation bit was designed in order to solve these problems, and its working principle and structure characteristics were also analyzed. The advantages of full screen liner and reverse circulation drilling technology are combined with this bit, by reducing the second damage to the hole wall to improve the borehole completion rate and depth, by sending the full screen liner to the hole bottom to avoid wall collapse and gas drainage channel blockage, the utilization rate of the gas drainage borehole is increased. The paper introduces this new bit about its configuration design, working principle and the application.