Corrosion of N80 carbon steel in oil field formation water containing CO2 in the absence and presence of acetic acid

Corrosion behaviour of N80 carbon steel in formation water containing CO2 was studied by polarization curve technique, electrochemical impedance spectroscopy, weight loss test, scanning electron microscope, and X-ray diffraction. Effects of temperature and acetic acid concentration on the corrosion behaviour of N80 carbon steel were discussed. The results showed that increasing temperature not only enhanced the dissolution of steel substrate, but also promoted the precipitation of FeCO3, the addition of acetic acid enhanced localized corrosion attack on N80 carbon steel. FeCO3 was the main corrosion product. And there was a transition region between CO2 corrosion control and HAc corrosion control.

► Effects of temperature and HAc concentration on N80 carbon steel were investigated.
► Temperature increased corrosion rate of N80 and precipitation rate of FeCO3.
► HAc increased corrosion rate of N80 and enhanced the local corrosion attack (pitting).
► FeCO3 was still the main composition of corrosion products in the presence of HAc.
► There was a transition region between CO2 corrosion control and HAc corrosion control.