Self-Excited Vibrations of Drillstrings

建议的分析研究的目的是为预测各种钻探作业中使用的钻头的动态稳定性极限提供技术基础。该研究将在钻头运动分析和动态稳定极限的确定中综合考虑轴向、扭转和横向模式的综合影响。对模式耦合影响的研究将显示哪些振动模式是关键的，并导致改变钻井系统结构稳定性的实用方法。研究成果将为减少钻柱失效、提高机械钻速提供技术指导。

The objective of the proposed analytical research is to develop a technical basis for predicting the limit of dynamic stability of drill bits used in various earth boring operations. The investigation will incorporate the combined effects of axial, torsional and lateral modes in the analysis of bit motion and in the determination of the limit of dynamic stability. A study of the effects of mode coupling will show which modes of vibration are critical and lead to practical methods of changing the structural stability of the drilling system. The knowledge gained from this research will provide a technical guidance for reducing drillstring failures and increasing penetration rate.