Abstract
One of the most important steps to ensure the integrity of offshore pipelines and subsea systems is a sound materials selection process with a properly designed corrosion mitigation strategy. This paper presents a systematic method of corrosion prediction, materials selection, and corrosion management for offshore pipeline system design, which includes production flowline, water injection line, gas lift line, MEG injection line, jumper, and subsea equipment piping. Carbon steel, which is widely used in oil and gas industry, is typically the first option considered for these structures due to its relatively low cost and available grades to meet different mechanical design requirements. However, carbon steel production systems may have their integrity threatened when exposed to demanding operating requirements (e.g. higher temperature and pressure) and corrosive substances (e.g. CO2, H2S, organic acids) during the lifetime. This paper discusses strategies to mitigate such threats, and these strategies include the corrosion allowance, chemical inhibition, and/or using alternative material options (such as corrosion resistant alloys, flexible pipes and internal coating) for offshore pipeline systems and subsea equipment. A case study is also be reported to demonstrate how corrosion assessment and materials selection can be performed during design phase of an offshore pipeline project.
