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| The Research of Corrosion Behavior and Protection of 3Cr Pipes in Production Wells Containing Oxygen Flooding |
| Received:September 29, 2020 Revised:November 19, 2020 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/issn.1672-9242.2021.01.006 |
| KeyWord:3Cr tubing and casing gas injection development oxygen flooding corrosion protection |
| Author | Institution |
| GU Lin |
CNOOC Research Institute Co., Ltd, Beijing , China |
| ZHOU Ding-zhao |
CNOOC Research Institute Co., Ltd, Beijing , China |
| CHEN Huan |
CNOOC Research Institute Co., Ltd, Beijing , China |
| HE Song |
CNOOC Research Institute Co., Ltd, Beijing , China |
| FENG Huan-zhi |
CNOOC Research Institute Co., Ltd, Beijing , China |
| ZHANG Zhi |
Southwest Petroleum University, Chengdu , China |
| XING Xi-jin |
CNOOC Research Institute Co., Ltd, Beijing , China |
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| Abstract: |
| Aiming at the problem of pipe corrosion in oxygen-containing gas development wellbore, this paper has systematically carried out dynamic corrosion experiment research on production wells, clarified the corrosion rate of pipes in the life cycle of oxygen-containing gas development wellbore, so as to provide data support and reference for the selection of anti-corrosion materials and anti-corrosion measures during the whole life cycle. The wellhead (27 ℃, 2.0 MPa), in-well (98 ℃, 13 MPa), and bottom (135 ℃, 18 MPa) working conditions of a production well in an oilfield in Bohai Sea are simulated to conduct dynamic corrosion experiments under different oxygen content conditions. O2 content accounts for the total gas 3mol%, using simulated oilfield associated gas components (CO2 content accounts for 4.13mol% of the associated gas components, 4.01mol% of the total gas components), the experiment period is 14 days, and the experiment material is 3Cr pipe. The control group is made of 13Cr material, and the test analysis is performed only in the bottom hole conditions. Due to the coexistence of O2 (3mol%) and CO2 (4.01mol%) in production wells, O2 has a significant catalytic effect on CO2 corrosion. At the same time, the conductivity of formation water is much higher than that of deionized water injected into wells, so the corrosion rate of pipes rises sharply with the increase of oxygen content. The test results show that the corrosion rates of 3Cr and 13Cr materials are much higher than the extremely severe corrosion level, and the use of materials alone for corrosion protection is not suitable for production well conditions in the target oilfield. In view of the characteristics of the synergistic corrosion conditions of oxygen and carbon dioxide corrosion, 3Cr material and imidazoline corrosion inhibitors should be used for corrosion protection, and oxygen concentration detection should be strengthened, or the use of duplex stainless steel 22Cr recommended by ISO 15156-3 and super duplex stainless steel 25Cr or 28Cr should be considered. |
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