考虑摩擦时水平井钻柱的稳定性分析

Analysis of Frictional Effect on the Drill Stem Stability in Horizontal Wells

分析摩擦对水平井钻柱稳定性的影响对于水平钻井作业的顺利进行是非常重要的．本文首先根据钻柱在水平井眼中的变形几何方程和静力平衡方程导出了钻柱的屈曲方程．通过线性化方程的小参数摄动解，讨论了不同边界条件下钻柱在水平并眼中的临界失稳载荷．绘制了不同摩擦系数（ｖ）下，无因次临界载荷（βｏｍ）与无因次长度（αＬ）之间的关系曲线；以及无因次钻压βＬ与临界无因次长度αＬＣ之间的关系曲线．本文的结果和有关的曲线可为水平井钻柱的稳定性计算和设计提供理论基础．

he frictional effect on the stability of drill stem in horizontal borehole is crucial to successful drilling of horizontal wells. The buckling equation of drill stem in horizontal boreholes was derived by analysing the deforming geometrical equation and the static equilibrium equations of drill stem. The critical unstable load under different boundary conditions is discussed on the basis of the perturbation solution of the linear buckling equation,s small parameters. Several figures and charts were drawn to show the relation between nondimensional critical buckling force βom and nondimentional length αL,and the relation between nondimentional drilling weight on bit βL and the critical nondimentional length QLC,etc.The results and charts given by the paper may provide a theoretical basis for calculating drill stem stability and designing the drill stem used in horizontal wells.