文章基本信息

标题：Corrosion Behavior of 3% Cr Casing Steel in CO2-Containing Environment: A Case Study
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作者：Lin Xu ; Jie Xu ; Ming-biao Xu 等
期刊名称：Open Petroleum Engineering Journal
印刷版ISSN：1874-8341
出版年度：2018
卷号：11
期号：1
页码：1-13
DOI：10.2174/1874834101811010001
出版社：Bentham open
摘要：Introduction: The production casing of 3% Cr steel has encountered severe internal corrosion in Huizhou Oilfield. To disclose corrosion behavior of inner casing, a series of corrosion exposure tests were systematically conducted on 3% Cr coupons in terms of in-field conditions. Material and Methods: Influence of exposure time, temperature, and water-cut on the CO₂ corrosion of 3% Cr steel was investigated, and analyses on weight loss, composition and morphology of corrosion product, and Tafel polarization curves were further carried out. Result: The results showed that the corrosion rate of 3% Cr steel increased with increasing temperature, but such trend descended when the temperature exceeded 65°C due to formation of an compact and adherent corrosion product film on the surface of 3% Cr coupons. While varying exposure time from 7 days to 14 days, the corrosion rate decreased, and the Cr and O enrichment was determined in the corrosion products. The corrosion rate of 3% Cr steel increased with a continuous increment of water-cuts, especially when the water-cut was larger than 40%. Conclusion: The localized corrosion can happen at the lower water-cut due to the presence of amorphous films. The main corrosion products were FeCO₃, Cr5O₁₂, Fe2O3, and Fe-Cr. Entry of CO₂ to the simulated formation water caused an increase in the anodic Tafel slope, and accelerated dissolution of 3% Cr steel.
关键词：3% Cr steel; Casing corrosion; CO₂ environment; Corrosion product film; Water-cut; Tafel polarization curve.