中文摘要：

考虑井壁周围岩体中流体的渗流作用，建立了套管错断口井壁岩体的平衡微分方程。然后按照损伤程度的不同将错断口井壁岩体划分为不同的区域（失稳破坏区、损伤区、弹性区），考虑不同区域内岩石材料参数的不同，分析了错断口周围岩体各个区域内的应力分布规律，确定了失稳破坏区和损伤区的半径，并在此基础上得到了岩体发生失稳破坏和损伤时的临界应力条件，从而为套管错断后井壁稳定性的研究和错断口吐岩块现象的预防提供了理论依据。

英文摘要：

The balanced differential equation of wellbore wall is built around failure casing considering fluid seepage. The area around failure casing is divided into different areas （unstable failure zone, damaged zone, elastic zone） according to the degree of damage, their stress distribution were obtained with consider- ation of variations of rock properties in different areas. The radius of unstable failure zone and damaged zone are determined. Critical stresses of rock failure and damage are obtained which provides a theoretical basis for the wellbore stability investigation and casing failure prevention.