State Feedback and Torque Feed Forward Combined Control System for Suppressing Drill-Strings Stick-Slip Vibration

基于状态反馈和扭矩前馈钻柱黏滑振动控制系统

¹ School of Power and Energy, Northwestern Polytechnical University, Xi’an 710072, China
² Systems Engineering Research Institute, China State Shipbuilding Corporation, Beijing 100094, China
³ Department of Municipal and Environmental Engineering, Taiyuan College, Taiyuan 044300, China

Received: 3 May 2018

Abstract

In drilling field, drill-strings stick-slip vibration is a common phenomenon and may lead to a series of drilling accidents. In order to improve drilling efficiency, this paper commits to study a new control system to suppress the undesired stick-slip vibration. In this work, a two degrees of freedom lumped parameter model is established to imitate the drill-strings. A state observer is proposed to estimate the unknown drill-strings states. A reference governor is put forward to optimize drilling parameters. In addition, in order to enhance the anti-interference ability of the closed-loop system, a torque feed forward is introduced into the control system. Based on the state observer and the reference governor, a state feedback and torque feed forward combined controller is designed. The simulation results indicate preliminarily that the designed state feedback and torque feed forward controller, compared with the drilling industry PI controller, has better dynamic performance and stronger ability to eliminate the drill-strings stick-slip vibration. Finally, the control system is applied in the drilling field. The experimental tests demonstrate that the designed controller can effectively suppress the drill-strings stick-slip vibration.

摘要

钻柱黏滑振动现象广泛存在于油气井的勘探开发。该振动容易造成钻柱连接松动，加快钻井部件的磨损和失效，从而降低钻井效率、威胁钻井安全。为了抑制钻柱黏滑振动，提出一种状态反馈和扭矩前馈结合的控制方案。基于建立的钻进系统双自由度集中参数模型，设计一种状态观测器，可以估计钻进系统难以测量的井下状态。并设计一种参考值优化算法，可以根据钻头与岩石间的摩擦扭矩，实时计算所有状态参考值和前馈扭矩输入量。结合状态观测器和参考值优化算法，实现了全维状态控制器的设计。仿真结果表明，在变化的非线性摩擦扭矩下，设计的控制方案对钻柱黏滑振动起到了良好的抑制效果。井场实验表明，设计的控制器可以应用于抑制钻井现场产生的钻柱黏滑振动现象。