气体钻井中接触非线性问题的数值算法研究

根据动量守恒和钻柱力学的基本理论,建立了气体钻井三维弯曲井眼钻柱动力学模型和钻柱与井壁接触碰撞模型;提出了一种求解钻柱与井壁接触非线性有限元方程的元胞自动机算法。该方法具有编程简单、收敛速度快等优点,以实际工况为例进行仿真模拟,选取有代表性节点的仿真计算结果并加以分析。仿真结果表明:该方法较好地解决了三维弯曲井眼中钻柱与井壁接触碰撞的复杂边界条件问题,在解决气体钻井钻柱与井壁接触非线性问题的研究中具有良好的应用前景。

A new algorithm for the nonlinear contact problem in gas drilling

The drill string dynamics model and the contact collision model of drill string and wellface in three-dimensional flexural wellbore in the gas drilling are established,according to the momentum conservation and the theory of drill string mechanics.This paper proposes a new cellular automata method for contact nonlinear finite element equations of drill string and wellface.The method has advantages of simple programming and converges fast,the actual working conditions are simulated and the simulation results of representative nodes are analyzed.It is shown that the method can be used to solve the complex boundary value problems of contact collision of drill string and wellface in the three-dimensional flexural well.