温度对连续油管QT-900在CO_2环境中腐蚀行为的影响

Effect of Temperature on Corrosion Behavior of Coiled Tubing QT-900 in CO_2 Environment

模拟某油田腐蚀环境,通过高温高压CO2腐蚀试验,采用SEM、EDS和XRD等测试手段,研究了连续油管QT-900在CO2环境中的腐蚀行为。结果表明,随着温度的升高,连续油管的均匀腐蚀速率和局部腐蚀速率均先减小后增大、再减小,分别在40℃和100℃时出现极大值。在承受最大拉伸应力时,平均腐蚀速率和局部腐蚀速率与不受力时相比均明显增加。在本试验条件下,局部腐蚀严重,最大可达4.635 5mm.a-1。腐蚀产物的主要成分为FeCO3。

The corrosion behaviors of coiled tubing in CO2 corrosion environment were studied by using SEM, EDS and, XRD testing methods. The results showed that with increasing temperature, the uniform corrosion rate and the localized corrosion rate of coiled tubing decreased first, then increased, and decreased again. The maximum variation appeared at 40℃ and 100℃. Under the maximum tensile stress, the uniform corrosion rate and the localized corrosion rate both increased more clearly than no tensile stress. In the present expersmental conditions, the localized corrosion was very severe, the maximum rate was up to 4. 635 5 mm · a-1. The corrosion products mostly were FeCO3.