Corrosion Electrochemical Experiments of Steel A3 in Oilfield Produced Water Containing Polymer

The corrosion behavior of oilfield produced water is complex owing to containing many anions and cations as well as a certain amount of polymer.Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were used to investigate the corrosion behavior of A3 steel in produced water under different conditions.The results showed that temperature had significant effect on corrosion in the sewage free of polymer.The corrosion potential shifted to negative as the temperature increased.EIS showed that the film on metal surface was easier to form at high temperatures.Polymer acted as an inhibitor in solution.Its inhibition mechanism was mixed inhibitory mode.The synergetic effect was rather complex when polymer,scale inhibitor and corrosion inhibitor were all added into the system.Warbury impedance appeared in the low frequency zone of Nyquist plot,indicating that the electrochemical process was mainly controled by diffusion step.