高温高含二氧化碳条件下五种含Cr钢适用性评价

Evaluation of Applicability of Five Cr-containing Steels at High Temperature and High Carbon Dioxide

目的预测某高温高含二氧化碳油井中管柱的腐蚀情况,为该油井推荐安全经济的材质。方法采用高温高压反应釜模拟现场工况进行腐蚀试验,通过失重法、扫描电子显微镜(SEM)和X射线能谱分析(EDS)对五种含Cr钢的适用性进行评价。结果在40~160℃温度范围内,五种钢材随温度的升高,其均匀腐蚀速率先升高后降低,且均在80℃时达到最大值。3Cr钢的腐蚀速率最高,在整个温度范围内,均远高于0.076 mm/a。在温度为120℃时,9Cr钢开始出现局部腐蚀。在温度为160℃时,13Cr钢有一定的局部腐蚀倾向。S13Cr、22Cr钢在整个温度范围内的腐蚀速率都较低,试验后试样表面平整连续,耐蚀性能好。结论建议在采出井井筒中上部40~80℃较低温度井段选用9Cr钢,中部80~120℃中高温井段选用13Cr钢,底部120~160℃高温井段选用S13Cr钢。

The work aims to predict the corrosion of the string in the high temperature and high carbon dioxide oil well and recommend safe and economical materials for the well.The actual working conditions were simulated by a high-temperature and high-pressure autoclave.The applicability of five kinds of Cr-containing steels was evaluated by weight loss method,scanning electron microscope(SEM)and X-ray energy spectrum analysis(EDS).Within 40-160℃,the uniform corrosion rate of five kinds of steel first increased and then decreased with the increase of temperature,and all reached the maximum at 80℃.The corrosion rate of 3Cr steel was the highest and was far higher than 0.076 mm/a in the whole temperature range.At 120℃,local corrosion of 9Cr occurred.13Cr steel had a tendency to corrode locally at 160℃.The corrosion rate of S13Cr and 22Cr steel was low in the whole temperature range.After the test,the surface of the samples was smooth and continuous with good corrosion resistance.It is suggested to use 9Cr steel in the upper section of low temperature(40℃~80℃),use 13Cr steel in the middle section of mid-high temperature(80℃~120℃)and use S13Cr steel at the bottom of high temperature(120℃~160℃).