Abstract:

There is abundant high mineralized oilfield brine in China，in order to provide security to the process of exploitation of oilfied and utilization of the brine，the methods of weight loss，SEM，EDS and EIS are applied to investigate the corrosion behaviors of carbon steel in the high mineralized oilfield brine.The results show the corrosion rate of carbon steel increases with the elevated temperature firstly，then decreases，the peak value occurs when the temperature is 70℃.The increasing mineralization accelerates the corrosion.Na+ has a tendency to deposit on the surface of steel as crystal of NaCl.However，Ca2+ participates in the formation of corrosion film，and the concentration of Mg2+ in the film is very low.The microcosmic defects give birth to the pitting.The pit steadily grows up if its dimension is over the critical value.The different electrochemical performances are observed at the stages of pitting initiation and development during the tested time.The equivalent circuits of the different corrosion stages are built.

Key words: brine, corrosion, pitting, corrosion film, electrochemical performance