N80钢在模拟深层气井水溶液中的CO_2腐蚀行为

CORROSION BEHAVIORS OF N80 STEEL IN SIMULATED WATER FROM DEEP GASWELL CONTAINING CO_2

利用高压釜、扫描电镜(SEM)和X-射线衍射(XRD)等手段,研究了温度、CO2分压、Cl-浓度、pH值和流速等因素对N80钢在模拟深层气井水溶液中腐蚀行为的影响.结果表明,温度对腐蚀速率的影响很大,随着温度的升高,腐蚀速率先增大后减小,80℃时腐蚀速率达到最大值,生成的腐蚀产物主要为FeCO3;降低溶液pH值、增加溶液中的Cl-浓度、提高CO2分压以及介质的流速,均加剧了N80钢的腐蚀.

Factors influencing corrosion rate of N80 steel in carbon dioxide environment were studied using autoclave, SEM and XRD. The results indicated that the temperature remarkably affects the characterization of corrosion product,and the corrosion rate increases along with the increasing of temperature up to 80℃ ,then reduces dramatically due to the formation of a protective layer on the surface of steel. Corrosion product was proved to be FeCO3 in higher temperature. Corrosion will be aggravated by reducing pH value and increasing the Cl^- concentration, CO2 partial pressure and the flow velocity of solution.