Gas control technology of sleeve milling and fishing for directional drilling in broken soft coal seam
YANG Xu;WANG Jianqiang;ZHANG Hongjie;ZHANG Jie;ZHANG Yazhou;HUANG Hanjing;CHEN Tianzhu
针对碎软煤层定向钻孔套铣打捞,孔壁失稳塌孔造成瓦斯异常涌出的技术难题,提出了碎软煤层定向钻孔防瓦斯套铣打捞技术。在现有套铣打捞技术基础上,分析了碎软煤层套铣打捞孔内瓦斯异常涌出原因、涌出通道和涌出量,优化了套铣打捞钻具内抽采瓦斯管路系统,将套铣打捞过程中打捞钻具内积聚瓦斯进行抽采并卸压;开发了套铣打捞孔口密闭抽瓦斯系统和套铣打捞加杆防瓦斯装置,实现套铣打捞全程负压抽采、密闭排渣和密封加杆。利用该技术成功处理1起孔深362 m的碎软煤层定向钻孔卡钻事故,事故处理中通过打捞钻具内抽采瓦斯管路系统,实现了打捞钻具内积聚瓦斯的抽采和卸压,通过孔口密闭抽瓦斯系统和加杆防瓦斯装置,实现了孔口和打捞钻杆末端口涌出瓦斯的密闭抽采,整个打捞过程中未发生瓦斯超限事故。
Aiming at the technical problem of abnormal gas outflow caused by collapsed holes in the process of directional drilling and sleeve milling in broken-soft coal seams, a gas prevention technology was proposed for directional drilling and sleeve-milling salvage in broken-soft coal seams. On the basis of the existing casing milling salvage technology, the gas drainage pipeline system in the casing milling salvaging drilling tool is optimized, and a large amount of gas accumulated in the salvaging drilling tool during the casing milling salvage process is drained and relieved. The salvage orifice airtight gas pumping system and the sleeve milling salvage rod anti-gas device can realize negative pressure extraction, airtight slag discharge and sealing rod addition in the whole process of sleeve milling salvage. The technology was used to successfully deal with a directional drilling stuck accident of crushed soft coal seam with hole depth of 362 m. In the treatment of the accident, the gas gathered in the fishing drill was extracted and pressure relieved through the gas extraction pipeline system in the fishing drill, and the gas gushing out of the hole and the end of the fishing drill pipe was realized through the closed gas extraction system in the hole and the anti-gas device in the rod. There was no over-limit gas accident in the whole salvage process.
directional drilling;gas gushing;stuck drill accident;sleeve milling and fishing;broken soft coal seam
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