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| Research Progress on Corrosion and Corrosion Protection of Offshore Oil Well Tubing in China |
| Received:September 28, 2020 Revised:December 05, 2020 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/issn.1672-9242.2021.01.001 |
| KeyWord:offshore oil well tubing CO2 environment H2S environment thermal production wells corrosion |
| Author | Institution |
| XING Xi-jin |
CNOOC Research Institute Co., Ltd, Beijing , China |
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| Abstract: |
| This article summarizes the practice of oil well pipe corrosion protection in marine environment in China and provides technical reference for similar oil and gas field development. The environments and corrosion status of offshore oil and gas wells in China are pointed out, and the anti-corrosion technologies are summarized according to the characteristics of the corrosion environments which can be divided into carbon dioxide downhole environment, sulfur downhole environment and high temperature environment of thermal production wells. Both the internal and external corrosions of oil and gas wells in the marine environment are serious. The external corrosion is mainly caused by atmospheric corrosion in marine environment, while the internal corrosion is mainly caused by CO2 corrosion. In addition, the change of fluid properties in the wellbores due to the operation needs also aggravates the internal corrosion. For CO2 corrosion environment, a marine anti-corrosion chart is established, and three low-cost anti-corrosion strategies are proposed. The research on the corrosion law of different materials and prediction of their service life are studied for H2S corrosion environment. The changes of the superimposed strength of oxygen content, corrosion at high temperature and thermal stress are studied for high temperature environment of thermal production wells. It is considered that the external corrosion of oil and gas wells in marine environment can be protected by coating, sacrificial anode and cathodic protection; CO2 corrosion in the wells can be handled by using the anti-corrosion material selection chart to select suitable materials, while combined string corrosion protection strategies can be used to reduce cost; H2S environment can use carbon steel or low chrome steel to reduce the risk of SSC and SCC; thermal production wells should control the influence of oxygen content and heat intensity attenuation. |
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