直井油管柱无重始弯压力研究

RESEARCH ON INITIAL BENDING DEFLECTION FOR NO-WEIGHT TUBING STRINGIN VERTICAL WELL

直井油管柱无重始弯压力是判断油气井中在某一工况条件下油管柱是否弯曲的根本依据,只有弄清楚直井油管柱是否弯曲才能分别按其是弯还是不弯进行针对性很强的、有效的管柱受力分析。直井油管柱无重始弯压力是有重始弯压力的基础,只有了解了直井油管柱无重始弯压力基本特征后,才能对直井油管柱有重始弯压力进行更合理、更有效、更深入地研究,也才能进一步解决直井油管柱弯曲(平面弯曲和空间螺旋弯曲)的一些理论和实践问题,进而更好地解决斜井、水平井中油管柱弯曲的理论和实践问题。文中先介绍直井无重油管柱的概念和弯曲特征,其次对弯曲等效管长与弯曲压力关系进行推导,再次说明弯曲有效管长的力学意义,最后再进行一些必要的讨论。

The stress of initial bending deflection for no-weight tubing string in vertical well is basis for judging bending deflection of tubing string on certain conditions.First,we must distinguish that the tubing string in vertical well is bending or straight,then force analysis for tubing string can be done effectively.And studying of the stress of initial bending deflection for no-weight tubing string is the prerequisite for actual tubing string.Only the basic features of the stress of bending deflection for no-weight tubing string are understood,the in-depth research on the stress of actual tubing string in vertical well can be carried out and the problems about theory and practice of bending deflection(plane bending and helical bending) are resolved for tubing string in vertical well,and thus the corresponding issue for inclined well and horizontal well can be better solved.This paper firstly described the concept of no-weight tubing string in vertical well and its bending features,followed by deducing the relationship between the effective bending tube length and bending stress,once again showed the mechanical significance of the effective bending tube length,and finally some necessary discussion was carried out.