摘要
基于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,建立了采用有限元法对变曲率井中有重钻柱屈曲过程进行分析的方法,给出了求解变曲率井中钻柱屈曲非线性方程的算法。力学模型中考虑了钻柱重力、井眼轨迹曲率半径变化率对屈曲的影响。分析结果表明:钻柱上端轴向载荷增大时,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;井眼的弯曲对钻柱屈曲具有抑制作用,井眼轨迹曲率半径变化率越大,钻柱的屈曲也越严重。
Based on the equilibrium equation and generalized function of the buckling of drill-tubing with weight in constant-curvature wells, the paper used FEA method to analyze the buckling of the drill-tubing with weight in variational-curvature wells. It put forward the algorithm for solving the nonlinear equations for the buckling of drill-tubing in variational-curvature wells. The effects of gravity of drill-tubing and curvature radius variation rate of well contrail on buckling behavior are considerd in the mechanical model. The analysis results show： with the increase of axial load, the buckling first occurs at the lower part of the drill-tubing where axial load is largest, then buckling spreads upwards, and finally buckling occurs at the entire drill-tubing; buckling displacement, constraint force per unit length of a well and the bending moment of drill-tubing vary periodically; the bending of the well inhibits the buckling of drill-tubing; the greater the change of well＇s curvature radius, the more serious the buckling of drilltubing is.
出处
《机械科学与技术》
CSCD
北大核心
2007年第5期672-676,共5页
Mechanical Science and Technology for Aerospace Engineering
基金
美国Smith Tool公司资助
中国博士点基金项目(20020287003)资助
关键词
变曲率井
钻柱
屈曲
非线性有限元分析
variational-curvature well
drill-tubing
buckling
nonlinear finite element analysis （FEA）
