- Title
- Corrosion of carbon steel under mixed deposits in simulated deoxygenated seawater environment
- Creator
- Wang, Xiang; Melchers, Robert E.
- Relation
- Australasian Corrosion Association Annual Conference: Corrosion and Prevention 2015. Proceedings of the Australasian Corrosion Association Annual Conference: Corrosion and Prevention 2015 (Adelaide, S.A. 15-18 November, 2015)
- Publisher
- Australasian Corrosion Association (ACA)
- Resource Type
- conference paper
- Date
- 2015
- Description
- Injecting seawater (and other water) into oil reservoirs to promote the rates of production is widely used in the offshore oil and gas industry. This is done using carbon steel water injection pipelines (WIPs) for which internal corrosion sometimes is a major problem. Field experience often shows severe corrosion at the bottom part of the pipelines. This is known as channelling corrosion, 6 o'clock corrosion or bottom of the line corrosion. Field observations also show the presence of deposits at the 6 o'clock position and evidence of bacterial activity and both under-deposit corrosion (UDC) and microbiologically influenced corrosion (MIC) usually are suspected. Some WIPs treated with nitrate show more severe channelling corrosion than those without nitrate addition. This is contradictory with the primary purpose of adding nitrate to try to suppress the metabolism of aggressive sulphate reducing bacteria (SRB) within the oil reservoir. To date, the mechanism of channelling corrosion is not fully understood. The present work reports an experimental pilot study of the corrosion of carbon steel specimens under mixed deposits and simulated deoxygenated seawater environment. The influence of the presence of deposits, the treatment of seawater by filtration and ultraviolet (UV) irradiation and the addition of nitrate were evaluated by exposing carbon steel specimens to different test environments. The steel specimens were recovered from experimental vessels after 180 days and 365 days of exposure. The surface topography changes of steel surfaces were examined by stereo microscopy. The development of pitting under different test environments and the relative contributions to the formation of channelling corrosion are discussed.
- Subject
- steel; under-deposit corrosion; seawater; deoxygenation
- Identifier
- http://hdl.handle.net/1959.13/1315267
- Identifier
- uon:22927
- Identifier
- ISBN:9781510822573
- Language
- eng
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