中文摘要：

针对钻柱和井壁之间的接触非线性特点,运用节点迭代有限元法计算钻柱的动态响应,研究了转速对钻柱动力学特性的影响,计算了钻柱涡动速度、涡动轨迹和横向加速度、纵向加速度。结果表明：钻柱和井壁之间碰撞频繁,过大的横向加速度、纵向加速度会使钻柱进入涡动状态甚至混沌运动状态,使钻柱产生较大的交变应力,导致钻柱的过早失效和井下测量工具的损坏。通过转速优化,可较大幅度地减弱钻柱的振动,降低钻柱的动态工作应力。该方法和结果对于工程实际具有指导意义,并为现场操作提供理论依据。

英文摘要：

Recognizing the contact nonlinearity between drillstring and borehole,the finite element iterative method is used to calculate the dynamic characteristics of drillstring,such as whirl speed,whirl orbit,lateral and axial accelerations. Furthermore,the effects of rotary speed on dynamic characteristics of drillstring are analyzed. The results show that high acceleration and frequency impact between drillstring and borehole wall may lead to whirl and chaotic motion,and increase the alternating stress. These severe vibrations may result in premature drillstring failure and damage to the downhole tools. By rotary table speed optimization,drillstring vibrations can be reduced and the dynamic stress can be controlled at a low level. The results are helpful to engineering applications and provide theory supports for drilling operations.