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通过引入单元荷载刚度矩阵，提出了一种用于分析钻柱结构稳定性问题的有限单元法。该方法可以用于分析变截面钻柱在变轴力和变横向力共同作用下的钻柱稳定性问题，也可用于分析弯曲井眼中钻柱的稳定性问题。在所建立的力学模型中，考虑了钻柱自重和井眼曲率的影响。分析结果表明，在斜直井眼中，除了钻柱自身密度及截面面积外，影响钻柱荷载的因素还有井眼状况及钻柱两端部的约束条件，但当钻柱长度超过８０ｍ时可以不考虑端部约束的影响。对于弯曲井眼，钻柱临界压力不仅与钻柱的长度、截面尺寸有关，还与井眼曲率有关，即随着曲率的增大而增大。
By introducing unit load stiffness matrix, a finite element method for analyzing the stability of drill string structure is proposed. The method can be used to analyze the stability of drill string under the joint action of variable axial force and variable lateral force. It can also be used to analyze the stability of drill string in curved boreholes. In the established mechanical model, the influence of the weight of the drill string and the curvature of the wellbore is considered. The results show that the factors that affect the load on the drill string are the wellbore condition and the constraint conditions of both ends of the drill string except for the self-density and cross-sectional area of the drill string. However, when the drill string length exceeds 80m, Consider the effect of end constraints. For a curved borehole, the critical pressure of the drill string is not only related to the length and cross-section of the drill string, but also to the curvature of the wellbore, ie, it increases with the curvature.