永城矿区煤矿排水钻孔施工技术

永城矿区某矿排水钻孔设计孔深584．1m，因钻孔与地下巷道平面位置相距仅15m，因此要求钻孔偏斜在表土层不大于0.3％，基岩段不大于0.5％。施工中选用稳定性好、扭矩力大的TSJ-2000型工程钻机，并配置850／5型泥浆泵进行钻井作业，钻进过程中严格控制钻进参数，并采取不同措施防止钻孔偏斜。井管加工严格执行技术标准，并在准备工作充分的情况下，一次安放到位。采用向管内连续注入泥浆，通过管底凡尔返到管外的方法进行井管壁外注浆。在注浆作业完成后72h．排除管内泥浆，完成排水钻孔施工。

Coalmine Drainage Borehole Construction Techniques in Yongcheng Mining Area

A drainage borehole designed depth is 584.1m in a coalmine of Yongcheng mining area. Because of horizontal location of drainage borehole away from underground roadway is only 15m, so the borehole＇s deflection limit in overburden not more than 0.3%, in bedrock 0.5%. TSJ-2000 drilling rig was selected for its better stability and larger torque moment, 850/5 type mud pump deployed to carry out drilling operation. Drilling parameters were strictly controlled during drilling; different measures have adopted to prevent deviation. Technical standard has strictly executed during well pipe machining and lowering to designated position at one go-off with adequate preparation. Carried out grouting by continuously inject mud into the pipe, then through pipe bottom valve gotten back to pipe outside. 72 hours after the grouting operation, remove mud from the pipe, then the drainage well construction finished.