求解井底钻具组合大变形的纵横弯曲法及其在导向钻具组合分析中的应用

SOLUTION OF BHA UNDER LARGE DEFORMATION BY BEAM-COLUMN THEORY AND ITS USE IN STEARABLE BHA ANALYSIS

在中半径水平井和大斜度共中，井底钻县组合（BHA）的力学特征属于大变形小应变性质。本文在求解BHA小变形的纵横弯曲法基础上，经过理论扩展，提出了求解BHA大变形的纵横弯曲法，列出了转盘钻下部钻具组合的三弯矩方程组及钻头侧向力和倾角公式；进一步导出适用于各种结构类型的导向动力钻具组合的三弯矩方程组通式，并以单弯稳定器钻具为例进行求解。文中给出了几条分析结论，可供设计和选择导向钻具组合时参考。

In the medium radial horizontal well and large tilt well, the mechaniCal characters of BHA is under large de formation with small strain. This paper presented the solution of BHA under large deformation by means of bom-column theory, on the basis of solution of BHA under small deformation, through the developing of theory. The formula of three bend moments of BHA undcr rotary drilling, bit side forces and tilt are given. The general formula of three bend moment fitting to stearable BHA with several structures is developed, and the solution of BHA with single bend sub and tow stabilizers is shown as an example. The analyzing conclusions are given for design and selection of stearable BHA