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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。
According to the nonlinear characteristics of the contact between the drill string and the borehole wall, the node dynamic response of the drill string is calculated by using the node iteration finite element method. The influence of rotational speed on the dynamic characteristics of the drill string is studied. The eddy velocity, eddy trajectory And lateral acceleration, longitudinal acceleration. The results show that frequent collisions and excessive lateral accelerations between the drill string and the borehole wall and the longitudinal acceleration cause the drill string to enter the whirling state or even the chaotic state, which causes large alternating stresses on the drill string and leads to over Early failure and downhole measurement tool damage. Through speed optimization, can greatly reduce the drill string vibration and reduce the drill string dynamic working stress. The method and result are instructive for engineering practice and provide a theoretical basis for field operation.