针对塔河油田地面管线频繁发生的腐蚀失效问题，利用高温高压反应釜模拟地面管线服役环境，开展了不同管材电化学测试和腐蚀挂片评价试验。通过电化学性能分析、微观形貌观测与腐蚀速率计算，明确其在塔河油田地面集输管线服役环境下的腐蚀变化情况。结果表明：在60 ℃,50%CO2含量下，20钢和1Cr钢为典型的阳极溶解特征，304管材发生钝化现象；304管材的极化电阻最大，其次是1Cr钢和20钢；随着温度与CO2含量的升高，3种管材的腐蚀加剧，腐蚀速率整体呈增大趋势。在70 ℃，70% CO2条件下，20钢与1Cr钢在气液两相中均发生局部腐蚀，20钢在气相环境局部腐蚀较轻微，1Cr钢局部腐蚀风险较大；304不锈钢在气液两相中发生均匀腐蚀，腐蚀速率较低。气相环境腐蚀产物主要为FeCO3和少量FeS；液相环境腐蚀产物主要为CaCO3、FeCO3。管材在气相环境由于凝析水发生局部腐蚀，液相环境中主要发生CO2腐蚀。因此，综合3种材料的腐蚀行为研究，304和20管材可作为塔河油田地面集输系统管材，而对于20钢在苛刻环境中的使用应关注其局部腐蚀风险。
For solving the problem of frequent corrosion failures of surface pipelines in Tahe Oilfield, the high temperature and high pressure reactor was used to simulate the service environment of the surface pipelines, and the electrochemical test and corrosion coupon evaluation test of different pipes were carried out. The corrosion variation conditions of such pipes in the service environment of the surface gathering pipeline in Tahe Oilfield were clarified through the electrochemical performance analysis, microscopic morphology observation and corrosion rate calculation. Results showed that under the condition of 60 ℃ and 50% CO2, the corrosion of 20# and 1Cr steels showed typical anode dissolution characteristics, while 304 pipes passivated. Additionally, 304 pipes had the largest polarization resistance, followed by 1Cr and 20# steels; With the increase of temperature and CO2 content, the corrosion of the three pipes was aggravated, and the overall corrosion rate showed an increasing trend. Under the condition of 70℃ and 70% CO2, 20# and 1Cr steels exhibited localized corrosion in gas - liquid two - phase, the 20# steel had slight local corrosion in the gas phase environment, and 1Cr steel had a higher risk of local corrosion. The 304 stainless steel uniformly corroded in gas - liquid two - phase with a relatively low corrosion rate. The corrosion products in gas phase environment were mainly FeCO3 and a small amount of FeS, and the corrosion products in the liquid phase environment were mainly CaCO3 and FeCO3. The pipe material corroded locally in gas phase environment due to the condensate water, and the main corrosion mode in liquid phase environment was carbon dioxide corrosion. Therefore, through the comprehensive research on the corrosion behavior of the three materials, it could be concluded that 304 and 20# pipes could be used as the surface gathering system pipes of Tahe Oilfield, and attention should be paid to the local corrosion risk when 20# steel was used in harsh environments.
