Abstract: Major factors having influence on the ultimate collapse strength of casing are represented as the ratio of diameter to wall thickness,the variation of wall thickness,the initial ellipticity and the material mechanical properties of casing.These factors are analyzed and calculated.Also represented are some fundamental concepts of designing the ultimate collapse strength of casing,and theoretical explanations of some coefficients involved in relevant equations,as well as some proposals regarding the calculation of the ultimate collapse strength of casing.The theoretical analyses and calculations represented in the paper can be applied to practical enigneering.

Key words: casing, elastico-plasticity, stability

摘要： 对影响套管极限外压的主要因素径厚比、变壁厚、初始椭圆率和材料机械性质等,进行了分析和计算;说明了套管抗挤设计中的若干基本概念,并从理论上解释了有关公式中的若干系数;对套管抗挤计算提出了一些建议.本文的理论分析和计算可供实际使用.

关键词: 技术套管, 弹塑性, 稳定