钻柱、钻头与岩石系统计算机仿真

国内外在研究钻柱振动时都把钻柱下端当作铰支，假设激振源为周期性的，偏离实际。本文从建立符合实际的下端边界条件入手，着重研究了钻柱的纵向振动。用有限单元法，求出整体质量、整体刚度，整体阻尼矩阵采用的是比例阻尼矩阵，利用牛顿法得到钻柱的振动方程，另外通过钻头与岩石的相互作用模型得到了真实的钻柱下端边界条件，并利用Ｈｏｕｂｏｌｔ软件，并进行了大量仿真实验，通过对实验结果分析得到了有意义的结论。

Computer Simulation of Drill String, Bit and Rock System

The researchers at home and abroad consider the end of drill string (DS) as hinge and assume that the excitation is periodic, which is by far from reality. This paper emphasizes the longitudinal vibration of DS with actual boundary condition of the lower end of DS. The whole mass matrix and stiffness matrix are obtained, from which the proportional damping matrix is also obtained. The real boundary condition of the lower end of DS is obtained by studying the interaction between roller cone bit and rock. The vibration equation is dissolved with HOUBOLT method, which is a sort of numerical solution method. We developed a simulation software according to the above vibration model. A lot of simulating experiments have been carried out. Some meaningful results are obtained which will guide drilling operation.