CO2 corrosion rates are strongly influenced by many mechanical and environmental factors, like: flow velocity, temperature, gas-liquid ratio, oil-water ratio, CO2 partial pressure, and the chemical composition of
the producing water. Under specific conditions, a corrosion product, iron carbonate (FeCO3), can deposit over the corroding metal as a scale. The iron carbonate scale layer represents a barrier to the CO2 corrosion
reactants, and can reduce the overall corrosion rates. The corrosion protection provided by the scales is closely related to the scales morphological characteristics. CO2 corrosion tests performed in a flow loop were used to generate and study FeCO3 scales. Iron carbonate scales were developed under various CO2 corrosion flowing conditions to study their development over carbon steel surfaces and the protectiveness these scales provide to this material. Electrochemical
Impedance Spectroscopy (EIS) techniques, applied throughout the duration of tests, were used as a tool for characterizing the scales in terms of the electrochemical processes that take place when the scale is present. In this study, EIS and SEM techniques were used to characterize and correlate the morphology and the protection given by the scales with several environmental conditions. Keywords: corrosion, CO2 corrosion, carbon steel, electrochemical impedance, pipe flow, CO2 corrosion
prediction, FeCO3 scale, morphology of scales