模拟川东某气田气井封隔器失效后套管面临的腐蚀环境，利用自制高温高压釜进行VM110SS套管钢在总压18 M Pa、CO2分压0．54 M Pa、H2 S分压0．41 M Pa、温度30～150℃条件下的腐蚀实验，得出了该气井工况下温度对VM110SS套管钢腐蚀速率的影响。采用扫描电镜和电子能谱分析方法对试样表面腐蚀产物形貌及成分进行分析。结果表明，VM110SS钢的平均腐蚀速率随温度的升高呈现先增大后减小的规律，气液相腐蚀速率最大值出现在90℃。在90℃气相中腐蚀速率为0．838 m m/a、液相中腐蚀速率为1．130 m m/a ，发生极严重腐蚀。所有实验温度条件下，试样均发生均匀腐蚀，且腐蚀产物以硫铁化合物为主。本实验为酸性气田在不同井深及温度条件下套管的腐蚀状况评估提供了参考。
Failure data from oilfield showed that casings which were designed according to API standards were deformed and collapsed in salt formations. The main reason for decrease in strength may be caused by non-uniform loading(NUL) that was not considered in traditional casing collapsing strength design or that the designing method should be improved and developed. Obviously, the calculation of casing collapse strength is one of the key factors in casing design. However, the effect of NUL on casing collapse strength was generally neglected in the present computational methods. Therefore, a mechanical model which can calculate casing collapse strength under NUL was established based on the curved beam theory of the elasticity and was solved using displacement method. Simultaneously, three anti-collapse experiments were performed on C110 casing under NUL, and the strain and deformation laws of three casings in the process of collapse were obtained by the electrical method. Yield limit of every casing was obtained by analyzing those data. Experimental results are consistent with the results of calculation of new model. It indicates that the model can be used to calculate yield limit loading of casings under NUL.
