大位移井钻柱粘滑振动机理分析及减振研究

通过将钻柱系统等统一成一个集中质量摆，分析了在非线性钻头扭长和钻柱与井壁间摩扭矩作用下钻柱系统的稳定性，并从钻柱氯转振动能量度，阐明了钻柱产生的粘滑振动的原因，在对非线性钻头扭矩和钻柱与井壁间摩扭矩进行适当简化的基础上，给出了钻柱产生的粘滑振动的判别式，分析了钻柱粘滑振动的影响因素及防止和消除钻柱粘滑振动可能 的途径和措施，并对顶部扭矩负反馈减振方法进行了讨论，给出了其数值模型拟结果。

Mechanism Analysis onTorsional Stick-slip Vibration of Drillstring in Extended Reach Well and Some Ways to ItsSuppression

Based on a simple torsional pendulum model, the stability of rotary drillstring subjected to nonlinear bit torque and friction between drillstring and the wall of wellbore is analyzed. And according to the relationship between the rate of drillstring torsional vibration energy varying with time and rotary speed, the mechanism of torsional stick-slip vibration is explained. Furthermore, the discriminant of drillstring torsional stick-slip vibration is formulated by simplifying the nonlinear external torque from the bit and the wall of wellbore, and the affecting factors and the ways to suppress and eliminate it are also analyzed. More attention is paid to the top torque feedback method, which means applying a varying rotary speed with top torque on the top end, and the numerical simulated results have been gotten.