摘要
建立了等曲率井中有重钻柱屈曲的平衡方程及对应的泛函表达式,用有限元法对等曲率井中有重钻柱屈曲过程进行了分析,给出了钻柱正弦屈曲和螺旋屈曲临界载荷的定义.力学模型中考虑了重力、钻柱上端井斜角和井眼轨迹曲率半径对屈曲的影响.分析结果表明:载荷增大时,钻柱的下端先出现局部屈曲,随后屈曲向钻柱上部扩展,导致钻柱发生整体屈曲,屈曲位移、井壁约束力线密度和钻柱弯矩都呈周期性变化;重力对等曲率井中钻柱的屈曲有较强的抑制作用,其影响不可忽略;井眼轨迹曲率半径越小,钻柱上端井斜角越大则对钻柱屈曲的抑制作用越强.
The equilibrium equations and the potential energy function of tubing buckling with weight in constant-curvature wells are derived. The buckling process of tubing with weight in constant-curvature wells is then analyzed by finite element method. The clear definitions of the critical load for sinusoidal and helical buckling are given. The effects of gravity, top deviation angle and curvature of the wells on the buckling behaviors are considered in the analyses. It is shown that with the increase of the load, the buckling first occurs at the lower portion of the tubing where the axial load is largest, then the buckling spreads upwards and finally entire buckling of the tubing occurs. The buckling displacement, the contact force of the wells and the bending moment of the tubing vary periodically. The gravity of tubing strongly weakens the buckling of the tubing whose effects cannot be neglected. The larger the curvature of the wells and the top deviation angle are, the weaker the buckling of the tubing is.
出处
《力学学报》
EI
CSCD
北大核心
2005年第5期593-599,共7页
Chinese Journal of Theoretical and Applied Mechanics
基金
美国Smith Tool公司和中国博士点基金(20020287003)资助项目.~~
关键词
等曲率井
钻柱
屈曲
非线性
有限元分析
constant-curvature wells, drill-string, buckling, non-linear, finite element analysis
