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本文将弯曲井眼中的底部钻具组合(英文名称为Bottom Hole Assembly，简称BHA)作为空间梁来处理，在考虑几何非线性因素的基础上，导出了相应的有限元切向刚度矩阵。然后，利用“施加”与“放松”约束的方法处理了钻柱与井壁之间的接触非线性问题，并且考虑了钻柱与井壁之间摩擦力的影响。在此基础上，建立了对大曲率弯曲井眼中的钻柱进行二重非线性有限元分析的基本方程，以及相应的牛顿－拉斐逊迭代求解技术。最后，通过数值算例和工程算例证明了本文方法的可靠性，所得结果为大曲率井眼轨迹控制提供了参考依据。
In this paper, the Bottom Hole Assembly (BHA) in the bent hole is treated as a space beam. Based on the geometric nonlinearity, the corresponding finite element tangential stiffness matrix is derived. Then, the non-linearity of the contact between the drill string and the borehole wall was dealt with using the methods of “apply” and “relax” constraints, and the influence of the friction between the drill string and the borehole wall was taken into account. On this basis, the basic equations for the double nonlinear finite element analysis of the drill string in a curved pipe with a large curvature are established, and the corresponding Newton-Raphson iterative solution is established. Finally, numerical examples and engineering examples are used to demonstrate the reliability of the proposed method. The results provide a reference for well curvature trajectory control.