受井眼约束带接头管柱的纵横弯曲分析

针对受井眼约束带接头管柱的纵横弯曲问题，将管柱变形分成3 类情形：无接触、点接触和连续接触。根据 管柱变形基本方程及接头处管柱的边界条件和连续性条件，分别求解3 种情形下的管柱变形曲线。利用无接触到点 接触以及点接触到连续接触的判别条件，分别求解了接触状态转换的临界参数，并分析了临界参数（φ）随管柱视半径 与接头视半径之比（λ）的变化规律。结果表明，当λ 比1 略大时，φ 对λ 的变化很敏感；当λ 大于2 后，φ 对λ 的变化 不敏感，并且趋于某一稳定值。以λ = 2 为例，详细描述了管柱弯曲接触状态转换的整个过程。计算结果可以为实际 作业中接头对管柱弯曲影响分析提供理论基础。

Deflection Analysis of a Tubular String with Connectors#br# Constrained in a Wellbore

Deflection of a tubular string with connectors constrained in a wellbore includes three cases: no contact，point contact and wrap contact. The deflection curves of tubular strings under the three cases were obtained on the basis of the fundamental equations of tubular strings buckling and corresponding boundary conditions. The critical parameters from no contact to point contact and from point contact to wrap contact were calculated according to the transitional conditions between different contact cases. The relationship between the critical parameters（φ）and the ratio of the apparent radius of the tubular string to that of the connector（λ）was analyzed. The results show that when λ is slightly larger than 1，φ is sensitive to λ，but when λ is larger than 2，φ is not sensitive to λ and tends to stay at a stable value. Take λ=2 for instance，the entire process of contact state transitions was depicted in detail. The results in this paper can be applied to the analysis of the effect of connectors on tubular strings buckling in field operation