UNDER DEPOSIT CORROSION ON EQUIPMENT SURFACES: MECHANISM, CONTROL AND CURRENT PROBLEMS

Under deposit corrosion a serious problem in the oil and gas industry causing failures in oil and gas pipelines, boiler and heat exchanger tubes, cooling systems and wastewater treatment plants. In general, there is no single universal mechanism of under deposit corrosion, as it can develop according to different scenarios depending on the chemistry of the environment and the nature of the deposit involved. In addition, under deposit corrosion is often combined with microbiological corrosion, which further complicates its mechanism and increases the damage caused. Currently, various mechanical and physical methods are used in the industry to combat under deposit corrosion with varying success. Under deposit corrosion management is generally difficult and requires a detailed understanding of its mechanism. The objective of this paper is to briefly review the current literature on under deposit corrosion. The paper discusses the main definitions, corrosion mechanisms and scale types. The relationship between scale structure and corrosion mechanism and the relationship with microbiological corrosion are studied. An overview of the main approaches to managing corrosion under deposits in the oil and gas industry is also presented.