| LIU Wan-ying,LI Jin-yu,GAO Ke-chao,ZHANG Zhi,SHANG Suo-gui,GAO Qiang-yong,MA Jin-xin.Effect and Mechanism of Temperature on the Corrosion Behavior of N80 Steel in Simulated Formation with Saturated CO2[J],51(8):353-362 |
| Effect and Mechanism of Temperature on the Corrosion Behavior of N80 Steel in Simulated Formation with Saturated CO2 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.08.031 |
| KeyWord:saturated CO2 temperature N80 steel corrosion behavior mechanism |
| Author | Institution |
| LIU Wan-ying |
School of New Energy and Materials, Chengdu , China |
| LI Jin-yu |
School of New Energy and Materials, Chengdu , China |
| GAO Ke-chao |
Exploration Department of Tianjin Branch of CNOOC China, Limited, Tianjin , China |
| ZHANG Zhi |
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu , China |
| SHANG Suo-gui |
Exploration Department of Tianjin Branch of CNOOC China, Limited, Tianjin , China |
| GAO Qiang-yong |
Exploration Department of Tianjin Branch of CNOOC China, Limited, Tianjin , China |
| MA Jin-xin |
Exploration Department of Tianjin Branch of CNOOC China, Limited, Tianjin , China |
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| Abstract: |
| The corrosion behavior and corrosion characteristics of N80 steel under the different temperature condition in the simulated oilfield formation water with saturated CO2 are studied, and its corrosion law and mechanism are explored. The change of the morphology, grain size and density of the corrosion product film occurred because of the temperature. The change furtherly caused the different degrees of corrosion of the substrate. At the temperature of 60 ℃, the surface of the substrate is evenly covered by the corrosion product film, and the film is flat and dense. A few pits appeared on the surface of the substrate when the corrosion products are cleaned off. When the temperature increases to 90 ℃, the corrosion products covered on the surface of the substrate are uneven. The crystal grains are coarse and their arrangement is chaotic. The regularity is worse than that of the corrosion products at 60 ℃. After the corrosion products are removed, large groups of corrosion pits occurs on the surface of the substrate and it occurs the sheet corrosion. At the temperature of 120 ℃, the grains of the corrosion products reduce. The coverage of film is uneven and it has obvious pits and cracks. Moreover, some of the corrosion products fall off. After the corrosion products are removed, a large area of corrosion pits occurs on the surface of N80 substrate, which showing the substrate with severe corrosion. The corrosion rate of N80 steel increases from 0.021 0 g/(m2.h) at 60 ℃ to 0.036 0 g/(m2.h) at 90 ℃ to 0.044 4 g/(m2.h) at 120 ℃. The self-corrosion current density of N80 steel increases from 1.362 3×10‒6 A/cm2 at 60 ℃ to 1.427 3×10‒6 at 90 ℃, and then to 1.785 1×10‒6 A/cm2 at 120 ℃. However, the self-corrosion potential decreases with the increase of the temperature. As the temperature rising, the corrosion product film gradually becomes loose, more porous and cracks, and the corrosion rate continues to increase. Therefore, the corrosion degree of N80 steel aggravated. |
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