Carbon capture, transport and storage (CCTS) has recognized as a major player for CO2 emission reduction, offering the only currently mature pathway capable of large-scale, long-term geological sequestration of CO2 captured from industry. Geological sequestration of CO2, both onshore and offshore, provides substantial storage capacity and high containment security. Geological CO2 storage systems are associated with complex geo-bio-chemical environments characteristic of mineralogy, brine composition, and phase behavior of CO2. Maintaining long-term wellbore and reservoir integrity is essential for permanent CO2 storage. Of various reasons causing integrity degradation of the storage systems, corrosion in supercritical CO2 environments exhibits characteristics distinct from those observed in conventional oil and gas reservoirs. The amount of CO2 dissolved in water deviates from Henry’s law under supercritical conditions. In addition to uniform corrosion, pitting, galvanic, stress-assisted cracking, and microbially influenced corrosion also occur. This talk discusses the uniqueness of supercritical CO2 corrosion in the storage environments, and introduces a multi-field coupled model to predict corrosion rate of steels in supercritical CO2 environments. By integrating mass-transfer, diffusion and charge-transfer steps across the steel/film/fluid interfaces, the model consider critical affecting factors and physical features that are related to steel corrosion.
