考虑制造缺陷的套管抗挤强度计算新模型

API 5C3未考虑套管的制造工艺及缺陷对套管抗挤强度的影响，已不能准确地预测套管实际抗挤强度。API/ISO工作组针对API 5C3存在的不足，修订了现行API 5C3标准，给出了含制造缺陷的抗挤新模型，大大提高了套管强度计算的科学性。研究中发现，ISO抗挤新模型并不适合所有壁厚段套管强度的计算，为此，在研究和评价ISO新抗挤模型的基础上，提出了考虑制造缺陷的抗挤强度计算新模型。通过与ISO/TG提供的上百个实物挤毁数据对比验证，本文所给出计算式的计算精确度明显好于API 5C3挤毁公式及ISO新模型，为套管强度的设计提供了新的参考依据。

A new calculation model for casing collapse resistance strength considering manufacturing imperfections

The influence of manufacture technology and manufacturing imperfections on casing collapse resistance strength is not included in API 5C3 standard,so the actual casing collapse resistance strength cannot be predicted accurately by API 5C3 standard.API/ ISO working group revised the current API 5C3 standard and proposed the new collapse resistance strength model with manufacturing imperfections,which upgrades the casing strength calculation accuracy significantly.The study on the ISO collapse resistance new model disclosed that it could not be used to predict the collapse resistance strength for all casing thickness.On the base of ISO collapse resistance new model,a new formula for predicting the casing collapse resistance strength was presented.Numerical and experimental comparisons show that the predictive values calculated by the new formula were proper and reliable,and the calculation accuracy is higher than that of API 5C3 standard and ISO new model.It supplied a new reference in casing designs.