Corrosion Behavior of Casing Steels 13Cr and N80 During Sequestration in an Impure Carbon Dioxide Environment
Corrosion of metallic materials,used as wellbore wall is a critical issue that influences the safety of carbon sequestration.This work focuses on understanding the corrosion behavior of casing steels in high-temperature and high-pressure CO2 storage environments.Herein,the corrosion behavior of two steels N80 and 13Cr in supercritical CO2-rich water phases containing impurities(SO2,NO2,and O2)was investigated via a high-temperature and high-pressure reactor by various pressure and stress conditions,aiming to simulate the real service conditions of carbon sequestration.The corrosion rate of steels was determined with mass-loss method,while the films formed on the steel surface were character-ized by means of scanning electron microscopy(SEM),X-ray diffractometry(XRD),and X-ray photoelec-tron spectroscopy(XPS).The results indicated that increasing the pressure led to higher rates of uniform corrosion and pitting corrosion for N80 steel.However,the pressure had inapparent effect on uniform cor-rosion of 13Cr steel,although severe pitting corrosion was observed by pressure of 20 MPa.Further-more,the applied tensile stress could induce damage of the corrosion product scales on both N80 and 13Cr steels to certain extent,nevertheless,no cracks were observed on the surface of the steel substrate.
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