瓦斯抽采钻孔堵塞段卡钻扭矩力学模型分析

Analysis of pipe-sticking torque mechanical model for gas extraction borehole clogging segment

为分析卡钻扭矩对瓦斯抽采钻孔施工的影响,基于粉体力学理论,建立孔内无压和孔内有压卡钻扭矩力学模型。分析钻孔堵塞区间风压p和钻机起拔力Fc对卡钻扭矩的影响规律。研究结果表明,对于孔内无压情况,形成卡钻扭矩较小,一般不会形成卡钻事故;因堵塞段孔内压力作用形成的孔壁径向侧压力pc是形成较大卡钻扭矩的本质原因,风压p和钻机起拔力Fc的增大将导致卡钻扭矩迅速增大,当卡钻扭矩达到了钻机的最大扭矩Tmax,堵塞段未被疏通时,将出现卡钻现象,处理不当容易造成钻杆破断、钻孔瓦斯燃烧、CO中毒等孔内事故。

To analyze the influence of pipe-sticking torque on gas extraction drilling engineering, a pipesticking torque mechanical model was built based on powder mechanics theory, different pressure p and pull-out force F on pipe-sticking torque were analyzed. Results show that for case of non-pressure in borehole, smaller pipe-sticking torque forms in drilling clogging segment, there would be no drilling accidents, that essential reason for formation of larger pipe-sticking torque is radial lateral pressure p, in borehole clogging segment, that torque will increase rapidly with increasing of air pressure p and pull-out force F that a pipe-sticking phenomenon would occur if clogging segment has not been effectively dredged when pipe-sticking torque has reached the maximum torque Tmax of drilling rig, and that drilling accidents are easy to happen if pipe-sticking phenomenon was dealt with improperly.