钻柱非线性螺旋屈曲准静态加载模型的数值验证

Numerical Verification of Quasi-Static Loading Model for Nonlinear Helical Buckling of Tubing in Constant-Curvature Wells

采用有限元法对等曲率井中钻柱非线性螺旋屈曲准静态加载模型的控制微分方程进行了求解,对准静态加载模型的合理性进行了数值验证,力学模型中考虑了钻柱的重力,澄清了钻柱螺旋屈曲特征值问题和准静态加载问题的理论基础。分析表明,等曲率井中钻柱的螺旋屈曲过程是一个稳定的加载过程,将等曲率井中钻柱的螺旋屈曲问题作为一个准静态加载问题来分析是合理的,采用准静态加载模型计算得到的钻柱初始失稳载荷与钻柱正弦屈曲线性特征值问题的分析结果吻合。

The governing differential equilibrium equations of the quasi-static loading model for nonlinear helical buckling of tubing in constant-curvature wells are solved by the finite element method. The rationality of the quasi-static loading model for helical buckling of tubing is verified. The effect of tubing gravity is included in the analysis. The theoretical bases of the quasi-static loading problem and the eigenvalue problem of drill-tubing helical buckling are presented. It is shown that the helical buckling process of tubing in constant-curvature wells is a stable loading process. It is reasonable that the helical buckling problem of tubing in constant-curvature wells is analyzed as a quasi-static loading problem. The initial buckling critical load of the quasi-static loading model is in agreement with the result of the linear eigenvalue problem of drill-tubing sinusoidal buckling.