双头高叶片螺旋钻杆高转速下排粉效率分析

Analysis of Drilling Cuttings Discharging Efficiency of Double Head and High Slice Screw Drilling Pipe Under High Rotating Speed

为了得到双头高叶片螺旋钻杆高转速下钻进时排粉效率影响因素和规律,运用离散元法对高速螺旋钻进时排粉运动规律进行了分析,使用EDEM软件分析了不同工况下排粉质量流、扭矩与转速关系。研究结果表明:煤粉靠钻具的给进挤压到螺旋槽中进行传输;给进速度一定时,当转速超过临界转速时质量流和扭矩不随回转速度变化而变化;停止给进排粉时,质量流随回转速度增大而呈正相关增大,扭矩随转速增大而指数式增加;塌孔排粉时,一定的塌孔流量下有其对应的临界转速,小于临界转速时质量流随转速增大而增大,大于临界转速后质量流趋于稳定。

In order to reveal the influencing factors of drilling cuttings discharging efficiency and laws in high speed drilling by double high slice screw drilling rod, the dynamic characters of drilling cuttings were analyzed based on discrete element method,the mass flow and torque in three conditions were obtained by EDEM. The results show that drilling cuttings are extruded to the spiral groove of screw drilling pipe through rotating and feeding; when the feeding speed is a fixed value, the mass flow and torque do not vary as the changes of rotating speed when the speed exceeds the critical speed; as to the＂discharging cuttings in the hole without feeding＂condition, the mass flow increases when rotating speed becomes higher, so as to the torque. However,the critical rotating speed exists in ＂rotating for discharging cuttings collapsed from roof＂condition. When rotating speed is lower than the critical rotating speed, the mass flow increases as rotating speed increases, but the mass flow is steady when rotating speed is higher than the critical rotating speed. The larger the amount of hole collapse is, the greater the critical speed is.