地面钻柱扭摆导向钻井的理论建模及应用研究

Theoretical Modeling and Application of Surface Drill String Torsion Pendulum Steering Drilling

在滑动导向钻井中,钻柱的扭摆可以将钻井过程中井眼与钻柱的静摩擦改为滑动摩擦,可有效减少钻探摩阻,并缓解滑动钻井中普遍存在的“托压”情况。基于滑动钻井技术,分区域构建了钻柱扭摆运动控制方程,通过理论模型研究扭摆角度(100°~600°)和扭摆速度(20~80 r/min)对扭摆深度、钻压及工具面变化的影响,并利用钻柱扭摆试验装置进行了试验。研究结果表明:随着扭摆角度、扭摆速度的增加,扭摆深度不断增加,钻压趋于平稳,扭摆减阻效果更好;过度增加扭摆角度、扭摆速度会造成工具面波动,影响钻井效率。现场应用结果表明,工具面平稳度高符合率达到96%,防“托压”效果明显,能够满足现场作业要求。研究结果可为钻柱扭摆导向钻井技术提供技术参考。

In slide steering drilling,the torsion pendulum of the drill string can change the static friction between the wellbore and the drill string during the drilling process to a sliding friction,thus effectively reducing the drilling friction and alleviating the common“backing pressure”situation in slide drilling.Based on slide drilling technology,the torsion pendulum motion control equation of drill string was established by zones.The theoretical model was used to identify the influences of torsion pendulum angle(100°-600°)and velocity(20-80 r/min)on the torsion pendulum depth,weight on bit(WOB)and tool face changes.Finally,the drill string torsion pendulum test device was used for tests.The research results show that as the torsion pendulum angle and velocity increase,the torsion pendulum depth increases,the WOB tends to stabilize,and the drag reduction effect of torsion pendulum is better.However,excessive increase in torsion pendulum angle and velocity would cause tool face to fluctuate and affect drilling efficiency.The field application results show that the coincidence rate of tool face smoothness is as high as 96%,the“backing pressure”prevention effect is obvious,meeting the requirements of field operations.The research results provide technical reference for the drill string torsion pendulum steering drilling technology.