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Corrosion Mechanism and Applicability Assessment of N80 and 9Cr Steels in CO{sub 2} Auxiliary Steam Drive

Journal Article · · Journal of Materials Engineering and Performance
; ; ;  [1]; ; ; ;  [2]
  1. Southwest Petroleum University, State Key Laboratory of Oil and Gas Reservoir Geology and Exploration (China)
  2. Engineering Technology Research Institute of Xinjiang Oilfield Company (China)
Corrosion tests were conducted in a high-temperature high-pressure (HTHP) autoclave to simulate the conditions of CO{sub 2} auxiliary steam drive in gas injection wells. Weight loss tests were performed with the sheets of N80 and 9Cr steels under the testing conditions. The morphology and composition of corrosion products were explored by SEM, EDS, XRD and XPS. The corrosion resistance of 9Cr steel was better than that of N80 steel under the testing conditions. The corrosion rates of N80 and 9Cr met the application requirements in CO{sub 2} auxiliary steam drive. The results broke the constraint in ISO-15156 standards. The corrosion process of N80 steel was mainly affected by the flow velocity. However, the corrosion process of 9Cr steel was mainly affected by temperature. The corrosion resistance of 9Cr steel depended on the FeCO{sub 3} content of Cr-rich layer, which was closely related to temperature. The low flow velocity influenced the diffusion process of N80 steel corrosive ions, whereas the high flow velocity influenced the integrity of corrosion scales. Considering the influence of flow velocity on the corrosion of tubing and casing, in the gas injection well, 9Cr steel and N80 steel were, respectively, selected as the materials of tubing and casing.
OSTI ID:
22970958
Journal Information:
Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 2 Vol. 28; ISSN 1059-9495; ISSN JMEPEG
Country of Publication:
United States
Language:
English