Key technology and practice of directional drilling for gas drainage in all the mining time and space in underground coal mine
LI Quanxin,XU Chao,LIU Jianlin,FANG Jun,ZHANG Jie,LIU Fei
针对高瓦斯和煤与瓦斯突出矿井高效瓦斯治理的迫切需要,为实现煤矿井下瓦斯全域化精 准抽采,提出了中硬煤层大盘区瓦斯抽采、碎软煤层瓦斯区域抽采和采动卸压瓦斯“ 以孔代巷” 抽 采的模式,利用定向钻孔轨迹精确可控、可沿目标地层长距离延伸的优势,在煤矿井下大区域范围 内实现“中硬煤层、碎软煤层、顶板岩层”全区域精准覆盖、“采前-采中-采后”全时段连续抽采,最 大限度实现全域快抽、应抽尽抽。 全面阐述了不同煤层赋存地质条件和开采阶段下矿井瓦斯治理 的技术现状与需求,系统分析了中硬煤层、碎软煤层和复杂顶板岩层中定向钻进成孔存在的技术难 点,在此基础上开发了中硬煤层超长孔定向钻进技术、碎软煤层气动定向钻进技术和复杂顶板岩层 大直径定向钻进技术,分析了各关键技术的适用条件和主要特点,并在我国典型煤矿区井下开展了 工业性试验和示范应用,工程实践表明:中硬煤层最大定向成孔深度达 3 353 m,实现了矿井大盘区 瓦斯抽采治理;碎软煤层中孔深 300 m 以上定向钻孔成孔率达 76%,实现了煤巷条带、采煤工作面 超前区域精准抽采;复杂顶板岩层中定向钻孔深度普遍达到 500 m 以上,一次扩孔直径可达 200 mm,推动了“以孔代巷”瓦斯抽采技术发展。 研究可为矿井瓦斯“零超限”和煤层“零突出”目 标的实现提供技术装备支撑。
To meet the urgent need for efficient gas control in high gas,and coal and gas outburst mines and realize a comprehensive and accurate gas drainage,the modes of gas drainage in the broader stope area of medium hard coal seam,the region of broken soft coal seam and the mining area for borehole instead of roadway are proposed. Taking advantage of accurate and controllable directional borehole trajectory and long distance extension along the target stratum,the gas drainage for medium hard coal seam,broken soft coal seam and roof stratum in a large region of underground coal mines can be accurately covered. The whole period of pre mining,production process and mined gas can be continuously extracted,so as to realize the gas drainage in different formations and mining times,and complete extraction to the greatest extent. The requirements and gas treatment for gas control under the different geological conditions of coal seam and mining stages are comprehensively expounded,the technical difficulties of directional drilling in medium hard coal seams,broken soft coal seams and complex roof strata are systematically analyzed. On this basis,the directional drilling technology for super long borehole in the medium hard coal seam,the pneumatic directional drilling technology in the broken soft coal seam,and the large diameter directional drilling technology in the complex roof strata are developed,and the applicable conditions and main characteristics of each key technology are analyzed. The industrial test and demonstration application are carried out in typical underground coal mining area in China. The engineering practice shows that the maximum directional borehole depth in a medium hard coal seam is 3 353 m,which realizes the gas drainage and control in a broader stope area of the mine. The borehole forming rate in a broken soft coal seam with a directional borehole depth of more than 300 m reaches 76%,which realizes the accurate extraction of coal roadway strip and advanced area of coal face. The depth of directional borehole in a complex roof strata generally reaches more than 500 m,and the diameter of one time reaming can reach 200 mm,which promotes the technological development of boreholes instead of roadways for gas drainage. The research can provide technical equipment support for the realization of the goal of “zero overrun” of mine gas and “zero outburst” of coal seam.
gas drainage;directional borehole;all the mining time and space;drainage mode
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会