高矿化度油气田盐卤水对碳钢的腐蚀行为研究

我国高矿化度油气田盐卤水资源丰富，为保障油气田开采和卤水综合利用过程的安全，采用失重法、扫描电镜、能谱分析和交流阻抗测试技术研究了碳钢在高矿化度卤水中的腐蚀行为。研究结果表明：碳钢的平均腐蚀速率随着温度的升高先增大后减小，在70℃时出现峰值，矿化度增大促进平均腐蚀速率升高；卤水中的Na+易于形成NaCl晶体沉积在钢表面，Ca2+有最大的参与成膜倾向，而Mg2+在产物膜中的含量较低；腐蚀产物膜的微观缺陷将导致点蚀源出现，当点蚀坑超过临界尺寸之后会稳定发展，随着时间增长，点蚀的诱发和稳定发展呈现不同的电化学特征，建立了相应的腐蚀等效电路。

RESEARCH ON THE CORROSION BEHAVIORS OF CARBON STEEL IN HIGH MINERALIZED OILFIELD BRINE

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.