油田采出水中含有多种无机阴、阳离子和一定量的聚合物,其腐蚀规律较为复杂.采用电化学极化曲线及电化学阻抗谱技术(EIS),研究了某油田采出水在不同条件下对A3钢的腐蚀规律.结果表明:温度对不含聚合物污水体系的腐蚀状况有一定的影响,随着温度的升高,自腐蚀电位负移,EIS测试表明高温下金属表面更易形成稳定的膜.聚合物的加入具有一定的缓蚀效果,作用机理为混合抑制型.当聚合物与缓蚀剂、阻垢剂同时存在时,表现出了复杂的协同作用机理.Nyquist图中低频区显示出明显的Warburg阻抗,表明此时金属在溶液中的电化学过程主要受扩散控制.

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.