Corrosion control of subsea production control systems: twenty years' experience

摘要

The integrity of subsea production control systems can be seriously affected by environmental degradation, primarily corrosion. Many of the components involved are of small size and with otherwise sophisticated design that does not tolerate any corrosion damage. Even a minor leakage may lead to immediate and severe malfunction of the system. Moreover, incipient corrosion that does not jeopardise the integrity of the component involved may still lead to contamination of internal fluids, causing sliding surfaces to seize or small-size nozzles to clog. Many components are exposed to both a corrosive external environment and potentially corrosive internal fluids. Such fluids may not be corrosive during normal operation but may develop corrosivity due to contamination, e.g. the ingress of seawater during subsea operations. Sometimes materials are used in combinations that are not compatible, causing severe galvanic corrosion if measures to control environmental corrosivity have failed.