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在水平井钻井过程中,钻柱由于受压很容易发生横向振动,引发钻柱失效、井眼扩径等严重事故。该文将受压柔性旋转钻柱简化为柔性旋转梁,将钻柱受到的复杂载荷简化到柔性旋转梁系统中,基于von Karman理论建立了柔性钻柱的动力学方程,再利用Galerkin法离散偏微分方程,得到了钻柱的非线性控制方程,并且利用多尺度法得到了平均方程。运用非线性动力学的方法分析柔性旋转梁在共振情况下的复杂动力学响应,得出系统中钻柱旋转角速度对非线性动力学响应的变化规律。研究结果可为水平井钻井过程中减少钻柱失效、提高钻速和降低钻井成本提供参考。
During horizontal well drilling, the drill string is easily subjected to lateral vibration due to compression, causing the drill string failure and borehole diameter expansion and other serious accidents. In this paper, the flexible rotating drill string is simplified as a flexible rotating beam, and the complicated load on the drill string is simplified into a flexible rotating beam system. Based on von Karman’s theory, the dynamic equation of the flexible drill string is established, and then the Galerkin method is used to discretize Differential equations, the nonlinear governing equations of the drill string are obtained, and the average equation is obtained by using the multi-scale method. The complex dynamics response of the flexible rotating beam under the resonance condition is analyzed by using the method of nonlinear dynamics. The variation law of the dynamic response of the drill string rotation angular velocity to the nonlinear dynamic response is obtained. The results can provide reference for reducing the failure of the drill string, increasing the drilling speed and lowering the drilling cost in horizontal well drilling.