Evaluation of various downhole materials under simulated CCUS environments - supercritical CO2 with impurities-, and comparison of different experimental techniques.

Paper ID: C2025-00035 ABSTRACT: The underground storage of supercritical CO2 could be critical for the integrity of downhole materials, especially when the presence of liquid water during shut-in or due to condensation is considered. The evaluation of suitable materials for such applications is complex due to the long-term exposures expected, the lack of standardized test, as well as the presence of impurities on the CO2stream that 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 state-of-the-art 30 days exposure tests to determine a baseline for materials performance and impurities effect, complemented with electrochemical and short-term (7 days) exposure tests run under equivalent conditions with the aim of providing a tool for a faster screening. The paper concludes on relative performance of the tested materials, as well as the value of various testing approaches to accelerate the much-needed learning curve when considering the multiple variables that could have effects on these applications.