Critical Points Regarding Internal Corrosion and Corrosion Control of Offshore Process Facilities

Abstract

Abstract Application of adequate corrosion control techniques to achieve the necessary safety and desired life of offshore process facilities are considered primary tasks of operators and authorities. The paper will describe different types of corrosion hazards and consequences of a corrosion failure for the different components of a process system. The following aspects will be considered: –accessibility of components–consequences of a corrosion failure–corrosion types such as CO2-corrosion, H2S-corrosion, erosion corrosion etc.–corrosion control techniques such as inhibitors, coating, corrosion resistant steels, etc.–corrosion monitoring with special emphasis to procedures for thickness measurements The work is primarily based on experiences from design evaluation and inspection of equipment which have been in service, but it is also supplemented by laboratory testing of corrosion rates and inhibitors. The so-called "sweet" corrosion which is caused by corrosive gases such as C02 and chlorides dissolved in the produced water is influenced by a number of parameters which are discussed. The "sour" corrosion type materialized by hydrogen induced stress corrosion is caused by H2S and water when unsuitable materials are used. Requirements on selection of materials and fabrication procedures and testing methods for application under sour conditions are reviewed. The application of corrosion control techniques to achieve the necessary safety and desired life of the equipment are considered primary tasks of both the operators and the authorities and different approaches may be used to achieve this goal.