深井套管柱安全可靠性影响因素分析

套管挤毁给油田造成了巨大的经济损失。采用弹性力学解析及有限元方法，给出了考虑磨损时套管剩余抗挤强度、抗内压强度以及非均匀地应力作用下套管外壁等效外挤载荷的计算方法，分析了非均匀地应力作用下不同套管磨损量对套管强度以及不同地层性质对套管地应力外挤力的影响。研究表明，当磨损度为109／6时，套管的剩余抗外挤强度和剩余抗内压强度降低约30％；套管内壁的Mises应力和套管外壁地应力外挤力随地层弹性模量的增大均明显减小，说明地层越硬，套管将偏于安全。

Influence Factors Analysis of Casing Safety Reliability in Deep Wells

During the oilfield development, production casing damage will cause tremendous economic loss. By using elasticity and finite element method, residual collapsing strength and residual internal pressure strength of worn casing and equivalent external pressure of casing outer wall under non-uniform geologic stress were derived. Effects of casing wear degree on residual strength of casing and stratum constants on equivalent external pressure of casing were analyzed. It was shown that residual collapsing strength and residual internal pressure strength of worn casing decrease about thirty percent when casing wear degree was ten percent. With the increment of stratum elastic modulus, Mises stress and equivalent external pressure of casing decrease greatly, which showed that casing was safe when stratum was hard.