油井管强度计算方法新ISO标准讨论

A Discussion on new ISO criteria for oil well casing strength calculation

张建兵 吕祥鸿 杨勇 刘歆

ZHANG Jianbing LV Xianghong YANG Yong LIU Xin

西安石油大学，陕西西安　710065 长庆油田勘探开发研究院，陕西西安　710021

对ISO/TR 10400 ：2007 和API Bul 5C3 ：1994 标准的油井管强度计算方法进行了对比分析，认为ISO/TR 10400 ： 2007 对油井管的强度计算方法的分类更符合油井管受力和强度性能的实际情况。新方法将可靠性工程方法引入了油井管的 强度性能计算，在方法上有大的进步，且新公式将管子的制造公差、管子矫直方式、热处理方式、探伤门槛值等因素考虑在内，建 模更加合理，计算结果更加精确。新方法分别给出了油井管的极限挤毁强度公式和设计挤毁强度公式，能满足不同情况下的使 用需要。对比分析结果表明，新方法油井管内压韧性破裂强度公式比旧标准计算值大，对径厚比小于20 的套管，新挤毁强度公 式计算结果比旧标准值小，对径厚比大于20 的套管，新挤毁强度公式计算结果比旧标准值大。ISO/TR 10400 ：2007 对油井强度认识的变化必然会影响现有的管柱强度设计方法。

Comparative analysis on the methods for oil well casing strength based on ISO/TR 10400:2007 and API Bul 5C3:1994 is conducted. It is regarded that the classiication of strength calculation methods based on the ISO/TR 10400:2007 is comparatively it for the actual situation of casing load and strength performance. The reliability project method is introduced into strength performance calculation by using the new method. Factors including the casing manufacturing tolerance, straightening manner, thermal treatment mode, inspection threshold value are taken into account, so the calculation results get more accurate. The formulae of ultimate collapse strength and design collapse strength are presented, meeting the requirements under various conditions. Comparative analysis shows that the calculated value of the internal pressure toughness collapse strength of oil well casing by using the new method is bigger than that based on the old criteria. As for the casing of which the diameter-thickness ratio is smaller than 20, the calculated result of the new collapse strength formula is smaller than the old criteria, while the calculated result is bigger as for the casing of which the diameter- thickness ratio is bigger than 20. The recognition change of oil well casing strength based on the ISO/TR 10400:2007 will exert effect on the current pipe string strength design method.