A comparative study on the corrosion behaviors of X100 steel in simulated oilfield brines under the static and dynamic conditions

Abstract

The influence of temperatures on the corrosion behaviors of X100 steel in simulated oilfield brines including CO2 under static and dynamic conditions at various temperatures up to 65 °C is investigated in the present paper. The static corrosion tests were conducted in a thermostatic water bath, and the dynamic corrosion tests were performed in the dynamic corrosion system. Potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) were used to study the corrosion performances of X100 steel. The microstructure and surface topography of the corrosion products were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results show that the dynamic corrosions became serious comparing with the static corrosions regardless of the temperature and immersion time. The corrosion current of the dynamic tests was 8 times higher than that of the static tests at 60 °C. When just immersed, the corrosion resistance of X100 steel decreased with the increase of temperature. When immersed for 24 h under static conditions, the corrosion resistance was highest at 60 °C. Under the dynamic conditions, the corrosion resistance decreased first and then increased with the increase of temperature. The corrosion products were mainly FeCO3 and Fe3C. The corrosion model was established. The relationship between the formation of the corrosion products and working conditions was also discussed and clarified.