基于钻柱扭转杆模型的扭矩负反馈减振系统优化设计方法

扭矩负反馈减振是控制和消除钻柱周向粘滑振动较为有效的方法之一。原有的扭矩负反馈减振系统优化设计是在将钻柱系统看作单自由度扭转摆的基础上进行的。针对大位移井中这种简化不合理的问题,通过将钻柱系统简化为连续质量扭转杆,建立了基于钻柱扭转杆模型的扭矩负反馈减振系统分析模型,推导出了其非零虚部极点方程。利用非零虚部极点方程的复数解与模态振动的频率及模态衰减指数间的对应关系,提出了以综合模态减幅系数最小化为目标的新的扭矩负反馈减振系统优化设计方法。数值模拟结果表明,对不适于简化为扭转摆的钻柱系统,采用基于钻柱扭转杆模型的新方法进行设计可以取得相对较好的减振效果。

Optimization design of torque feedback system based on drill string representative one-dimensional continuum

The torque feedback system is a successful technology for eliminating stick-slip vibration of drill-string assembly. In order to optimize the torque feedback system, the drill string is often simplified as a single-mode torsion pendulum. This simplification is unsuitable for the drill-string assembly in the extended reach well. According to the relationship between the solution of frequency equation and modal parameters, a new optimization design method was brought forward, taking the minimization of modal damping factor as an object function. The drill-string assembly was simplified as one-dimensional continuum. A mathematical model for the drill-string mounted torque feedback system was established, and the frequency equation for the system was derived. Numerical simulation shows that the new method is more effective for the drill-string assembly unsuitable to be simplified as a torsion pendulum.