The article covers the results of the comprehensive anticorrosive protection approach implementation for the subsea gathering and transport pipelines, oil-gas-fluid mixture treatment pipelines at Vietsovpetro offshore facilities. The process and linear subsea oil pipelines have been designed and laid for gathering and transporting the oil-gas-fluid mixture (the mixture of oil, associated gas and reservoir water), and treated commercial oil between the oil production and process platforms, as well as between the floating storage and offloading unit on Vietsovpetro fields. The author consider the actions on protecting the subsea pipelines from external and internal corrosion, and main factors that affect the safe operation: an increase of water cut, hydrogen sulphide and carbon dioxide content in the produced medium leads to evolvement of corrosive processes on the internal side of the pipelines. Lack of pig lunching and receiving chambers complicates the in-line diagnostics and cleaning of the internal pipeline walls in order to analyse the actual condition of the pipelines. The special attention is given to the assessment of acid solutions corrosivity while performing the bottomhole treatment and scale removal operations. Considering the actual operational lifetime of the pipelines, it is required to implement an inhibitor protection and corrosion monitoring, and perform the actions aimed at cleaning and inspecting the internal side of the pipelines with the high corrosive risks.
References
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