【目的】我国煤层赋存地质条件复杂，碎软煤层分布广泛，高瓦斯和煤与瓦斯突出矿井众多，目前采用钻孔瓦斯抽采是防治瓦斯灾害的有效措施。碎软煤层常规回转钻进存在轨迹不可控、成孔深度浅、抽采盲区大，常规定向钻进卡埋钻事故多、成孔困难、钻进效率低等问题。【方法】系统阐述了煤矿井下碎软煤层钻进技术的发展历程与应用现状，研制了气动螺杆钻具、定向钻机、随钻测量系统、除尘泵车、空压机或制氮机、油雾润滑装置等组成的煤矿井下气动定向钻进装备，并配套开发了气动定向钻进工艺和筛管完孔技术等关键技术，解决碎软煤层定向钻进成孔难题，保障瓦斯抽采效果。利用该成套技术与装备在两淮、山西、贵州等地区煤矿进行的碎软煤层定向钻孔试验。【结果和结论】研究表明：(1)气动定向钻进技术是碎软煤层钻孔瓦斯治理的有效技术手段，其钻进深度普遍达到200 m以上，最大钻孔深度达607 m，且可有效控制钻孔轨迹在目标煤层中延伸，煤层钻遇率达90%以上。(2)现场试验表明，气动定向钻进成孔效果好、施工效率高，最大效率达到3 594 m/(台·月)，有力推动气动定向钻进技术从小规模试验到大规模的工业化推广应用。结合此成套技术与装备的应用现状和煤矿安全高效生产对钻探技术装备的发展需求，提出煤矿井下气动定向钻进技术与装备的拓展应用方向以及向自动化、智能化和集约化方向发展的现实需求和必然趋势。

[Objective] The geological conditions of coal seams in China are complex, with a wide distribution of broken-soft coal seams, and a large number of wells have the problems of high gas and coal-gas outburst. Currently, borehole gas drainage is an effective measure for preventing and controlling the gas disasters. [Methods] In response to the problems of uncontrollable drilling trajectory, shallow drilling depth, large blind spots of drainage in conventional rotary drilling process of broken-soft coal seams, as well as multiple stuck drilling accidents, great difficulty in drilling and low drilling efficiency in conventional directional drilling processes, the development history and application status of drilling technologies for the broken-soft coal seams in underground coal mines was systematically introduced. Accordingly, the pneumatic directional drilling (PDD) equipment composed of pneumatic screw drilling tools, directional drilling rig, measurement while drilling system, dust removal pump truck, air compressor/nitrogen generator and oil mist lubrication device, as well as the key supporting technologies such as PDD technology and screen completion technology, has been developed to overcome the challenges of directional drilling in broken-soft coal seams and ensure the effectiveness of gas drainage. Besides, directional drilling test using the complete set of technology and equipment was conducted in the broken-soft coal seams of mines in Huainan, Huaibei, Shanxi, Guizhou and other regions. [Results and Conclusions] The research showed that: (1) The PDD technology is an effective technical means for gas control in broken-soft coal seam drilling. Its drilling depth generally reaches over 200 m, with a maximum drilling depth of 607 m. Besides, it can effectively control the extension of the drilling trajectory in the target coal seam, and the coal seam drilling encounter rate reaches over 90%. (2) The field test showed that the pneumatic directional drilling has good drilling results and high drilling efficiency, with a maximum drilling efficiency of 3 594 m per month with one rig, effectively promoting the application of PDD technology from in small-scale testing to large-scale industrialization. Based on the current application status of this complete set of technology and equipment and the development needs of safe and efficient production in coal mines for the drilling technology and equipment, the expanding application direction of PDD technology and equipment in coal mines, as well as the practical needs and inevitable trends towards automation, intelligence and intensification, was proposed.