Evaluation of Crevice Corrosion Resistance of CRAs by Different Testing Methodology under CO2 Injection Well Conditions

Abstract Nowadays, material selection for captured impure CO2 injection wells is one of the trending topics among corrosion engineers. However, to reproduce the environmental conditions under a well-defined protocol at the laboratory is a key testing challenge, especially considering that the specific international standards to follow are still under development. In this work, three different cold hardened corrosion resistant alloys (CRAs), one superduplex S32750, alloy 28 N08028, and alloy G3 N06985, were selected to be tested under a simulated CO2 injection well field condition: total pressure of 2540 psi, with 0.15 psi O2, 0.01 psi SO2, 0.01 psi NO2 and 2530 psi CO2 at a temperature of 40 °C, in contact with a 180000 ppm Chlorides concentration solution. The first objective was screening the different materials based on their crevice corrosion resistance. The second objective was to compare the obtained results under two completely different testing protocols regarding impure CO2 fluid management along the test and type of crevice setup. Finally, a complete metallographic characterization of a selection of the tested specimens was carried out to examine the different features observed on their surface and its relationship with their chemistry and microstructure. The resultant final screening of materials may be related to their critical localized corrosion temperatures.