大盘区瓦斯抽采超长定向钻孔施工关键技术措施

Key Technical Measures for Construction of Extra-long Directional Drill Holes for Gas Extraction in Large Panel Area

大盘区瓦斯抽采是煤矿井下区域瓦斯治理的新模式,要求单个钻孔长度覆盖整个工作面甚至超过3 000 m。目前煤矿井下顺煤层超长定向钻孔施工存在滑动钻进阻力大,钻机推进力达到极限,沿程水头损失大,泥浆泵压力达到极限,随钻测量信号衰减,测量深度达到极限等技术瓶颈。通过装备与工艺改进,行成了水路优化、水力加压螺杆钻具、泥浆脉冲系统结构优化、控制钻孔弯曲强度、提高复合钻进比例、扭摆减阻钻进、保证全煤层钻进及复合开分支等8项关键技术措施。在保德矿二盘区进行了现场试验,使超长定向钻孔深度从2 570 m成功提升至3 353 m,试验结果表明,该技术措施突破了上述三大技术瓶颈,有效提升了钻机及配套装备施工能力,具有明显的推广应用价值。

Gas extraction in large panel is a new mode of gas control in underground coal mine,required that the length of a single drill hole covers the whole working face and even exceeds 3 000 m.At present, extra-long directional drilling along coal seam in coal mine exist the technical bottleneck with the great resistance sliding drilling give rise to the propulsion force of the drill reaches the limit,great frictional head loss give rise to the mud pump pressure reaches the limit, attenuation of signal measurement while drilling give rise to the measured depth reaches the limit and so on. Through equipment and technic improvement, eight key technical measures have been taken, including optimization of waterway, hydraulic pressure screw, optimization of mud pulse system structure, controlling the bending strength of drilling holes, increasing the composite drilling ratio, torsional pendulum drag reduction drilling, ensure full coal seam drilling and compound drilling opens branch holes. Field test were carried out in No.2 panel of Baode mine, the extra-long directional drilling depth was successfully increased from 2 570 m to 3 353 m, the experimental results show that, this technical measure breaks through the above three technical bottlenecks, and effectively improves the construction capacity of drilling rig and supporting equipment and has obvious popularization and application value.