| In order to protect oil and gas well tube of the use of safe and reliable, This paper choose the TP140 and HP-13 Cr as the research object. Crevice corrosion characteristics and susceptibility of TP140 couple with crevice former including PTFE, HP-13 Cr and TP140 itself were investigated using high-temperature autoclave that was used to simulate high temperature and pressure environment of downhole 、contourgraph and SEM.Crevice corrosion characteristics and susceptibility of HP-13 Cr couple with crevice former including PTFE, G3 and HP-13 Cr itself were investigated using the same approach with TP140.The crevice corrosion mechanism of TP140 and HP-13 Cr were revealed using potentiodynamic polarization test and electrochemical impedance spectroscopy technique in simulating formation solution at 90℃. In addition,High-temperature autoclave and electrochemical testing methods were used to study the tensile stress for TP140 and HP-13 Cr crevice corrosion in the formation water simulation.The results obtained as follows:（1）TP140 and HP-13 Cr showed different corrosion characteristics and crevice corrosion mechanism in simulating formation solution including CO2. Crevice corrosion of TP140 were mainly composed of uniform corrosion,and its mechanism mainly accord concentration.Unlike TP140,crevice corrosion of HP-13 Cr mainly dominated by pit corrosion, and its mechanism mainly conform to IR drop.（2）TP140 and HP-13 Cr had higher crevice corrosion susceptibility in simulating formation solution including CO2. The corrosion of TP140 and HP-13 Cr were serious in liquid phase than gas phase, which is attributed to the significant influence of galvanicpromoting effect.their crevice corrosion susceptibility could use potentiodynamic polarization test and electrochemical impedance spectroscopy technique to evaluate.（3）On the whole, the tensile stress could effect crevice corrosion of TP140 and HP-13 Cr.The tensile stress was more larger,the crevice corrosion more serious. |
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