Sulfide Scaling and Corrosion of Carbon Steel in a Sour Medium

Abstract

The damage caused by the building up of scale inside wellbores and pipelines costs millions of pounds each year. A better understanding of scale formation and the kinetic nature of the process is essential, for asset management in general and the development of new protection approaches. Surface scale formation is one of the important factors related to the corrosion rate. The internal corrosion of carbon steel in the presence of hydrogen sulfide represents a significant problem for both oil refineries and gas treatment facilities/pipelines. Many studies have revealed that the system is complex since more than one iron sulfide compound may form. However, the kinetics of scale formation, such as the nucleation and growth processes of the scale are not at all well-understood and how corrosion inhibitors interact with scales. The kinetics of the scale formation will be investigated by using a variety of methods, some more successful than others. The methods employed include SEM, TEM, EDX, and Raman analysis, and this was done with the aim of obtaining the physical structure, the chemical composition and the crystal structure of the iron sulfide scale formed at different time scales.