Zhong Xiankang, Wang Yanran, Liang Jianjun, Chen Long, Song Xiaoqin
School of Oil and Natural Gas Engnieering, Southwest Petroleum University, Chengdu 610500, China.
Engineering Technology Institute, Xinjiang Oil Filed Company, CNPC, Karamay 834000, China.
Materials (Basel). 2018 Sep 6;11(9):1635. doi: 10.3390/ma11091635.
Flue gas injection for heavy oil recovery has received a great deal of attention, because it is more cost effective than lots of other injection methods. However, the corrosion could occur easily, because the flue gas usually contains corrosive gases such as CO₂, H₂S, and O₂. In this work, the corrosion behaviors of G20 steel in flue gas injection environment simulating Xinjiang oil field (China) were investigated using weight loss measurement and surface characterization techniques. The effect of environments including the O₂-containing environment, the H₂S-containing environment, and the O₂-H₂S-coexisting environment on the corrosion of G20 steel in gas phase and liquid phase was discussed. The results show that the corrosion rate of G20 steel in the O₂-H₂S-coexisting environment is much higher than the sum of corrosion rates of the O₂-containing environment and the H₂S-containing environment, regardless of the gas phase and the liquid phase. This indicates that there is a coupling effect between O₂ and H₂S, which can further accelerate the corrosion of steel in O₂-H₂S-coexisting environment. The results of surface characterization demonstrate that in a typical flue gas injection environment, the corrosion products are composed of FeCO₃, FeS, FeO(OH), and elemental sulfur. Elemental sulfur could obviously accelerate the corrosion of steel. Therefore, it can be considered that the coupling effect of O₂ and H₂S on corrosion of G20 steel in flue gas injection environment is caused by the formation of elemental sulfur in corrosion products.
注气开采稠油已受到广泛关注，因为它比许多其他注气方法更具成本效益。然而，由于烟气通常含有CO₂、H₂S和O₂等腐蚀性气体，腐蚀很容易发生。在这项工作中，采用失重测量和表面表征技术研究了G20钢在模拟中国新疆油田的注气环境中的腐蚀行为。讨论了含O₂环境、含H₂S环境以及O₂-H₂S共存环境对G20钢在气相和液相中腐蚀的影响。结果表明，无论在气相还是液相中，G20钢在O₂-H₂S共存环境中的腐蚀速率远高于含O₂环境和含H₂S环境的腐蚀速率之和。这表明O₂和H₂S之间存在耦合效应，可进一步加速钢在O₂-H₂S共存环境中的腐蚀。表面表征结果表明，在典型的注气环境中，腐蚀产物由FeCO₃、FeS、FeO(OH)和元素硫组成。元素硫可明显加速钢的腐蚀。因此，可以认为O₂和H₂S对注气环境中G20钢腐蚀的耦合效应是由腐蚀产物中元素硫的形成引起的。
