Evaluation of Various Downhole Materials under Simulated CCUS Environments - Supercritical Co2 with Impurities - and Comparison of Different Experimental Techniques

Abstract The underground storage of supercritical CO2 could be critical for the integrity of downhole materials, especially in the presence of liquid water during shut-in or due to condensation. The evaluation of suitable materials for such applications is complex due to long-term exposure, the lack of standardized test, as well as the presence of impurities in the CO2 stream can modify (expand) the type of corrosive species to be considered in comparison with typical environments in oil & gas production. In this paper, we summarized the efforts to understand the relative performance of 13Cr, Super 13Cr and Super Duplex 2507 in supercritical CO2 simulated environments containing NO2, SO2, H2S, O2 and H2 as impurities. The experimental program included electrochemical, 7-days, and 30-days exposure tests run under equivalent conditions to determine a baseline for materials performance and impurities effect. The paper concludes on relative performance of the tested materials, as well as the validity of various testing approaches to accelerate the much-needed learning curve when considering the multiple variables that could have effects on this application.