石油钻井底部钻具组合大挠度三维分析

Three-Dimensional Analysis of the Static Behavior of BHA Under Large Deflection

精确描述了石油钻井底部钻具组合在三维弯曲井眼中的变形约束条件及边界条件，应用加权余量法，对底部钻具组合静力大挠度问题进行了三维分析研究，并编写了相应的计算机分析程序。该程序可以在普通微机上运行，能迅速模拟计算底部钻具组合任一点的挠度、转角和内力，同时求得钻头对地层的机械作用力和偏转角。通过算例分析，本文初步阐明了井眼曲率及方程中的非线性项对钻头力学特性的影响效果。

The constrained and boundary conditions of BHA deflection in 3-D curved borehole have beenmodeled exactly in this paper.Three-dimensional analysis of the static behavior of BHA under largedeflection has been carried out successfully with the method of weighted residuals.The BHA an alvsisprogram thus developed can be run on a micro-computer to compute rapidly BHA deflections,tilt an-gles and internal forces including the bit behavior.In addition,this paper discusses some effects ofhole curvatures and the non-linear items on the bit behavior by ease study.