Modeling and experimental study on the effects of temperature on the corrosion of API carbon steel in CO2-Saturated environment

Abstract

This paper presents the results of a corrosion study conducted in carbonated brine (2% NaCl solution). All experiments were performed for a one-week duration at a total pressure of 41.37 MPa. The main test variables were temperature (38, 71, and 107 °C) and specimen material type (T95, C110, and Q125). The weight loss technique is used to assess the average corrosion rate (ACR). To detect the presence of localized corrosion, the actual load-carrying capacity (LCCT) of specimens was measured and compared with the one predicted from weight loss (LCCuc). Besides this, corrosion scale and specimen surface were examined using a digital microscope to investigate the presence of localized corrosion and explain ACR and LCCT measurements. To forecast corrosion under a CO2 saturated environment, a new model has been formulated considering a scale-forming condition.Results demonstrate the strong impact of temperature on the CO2 corrosion of API grade carbon steels (T95, C110, and Q125). Regardless of the material type, the highest corrosion rate was observed at 38 °C. Q125 displayed the highest CO2 corrosion resistance. All tested materials were prone to localized corrosion at high temperatures (71 and 107 °C). Model predictions show reasonable agreement with measurements displaying a discrepancy of mostly below 20%.