20钢在模拟CO_2驱工况环境中的腐蚀行为

Corrosion Behavior of 20 Steel in Simulated Working Environment of CO_2 Flooding

采用高温高压釜动态模拟CO_2驱工况环境,使用失重法研究温度和CO_2分压对20钢腐蚀速率的影响,利用离子色谱分析试验前后钙镁离子的含量,并用扫描电镜(SEM)和X-射线衍射仪(XRD)表征腐蚀形貌和产物成分。结果表明:20钢发生了严重CO_2腐蚀,其腐蚀速率随温度升高而增大、随CO_2分压的增大呈现先降低后增大的趋势;CO_2分压促进采出水中钙镁的沉积;腐蚀产物主要是FeCO_3。

Corrosion tests of 20 steel in simulated working environment of CO2 flooding were carried out in high- temperature and high-pressure autoclave, the effects of temperature and CO2 partial pressure on corrosion rate of 20 steel were studied by weight loss method. The contents of calcium and magnesium ions before and after experiment were analyzed using ion chromatography, the corrosion morphology were observed by SEM, and the composition of corrosion scales were analyzed by XRD. The results show that 20 steel suffered from serious CO2 corrosion, the average corrosion rate increased gradually with the increase of temperature, and decreased first and then increased with the increase of COz partial pressure. The increase of CO2 partial pressure quickened the deposition of Ca^2＋ and Mg^2＋ in producing water, and the corrosion products were mainly composed of FeCO3.