Effects of Depositing Characteristic and Temperature on Elemental Sulfur Corrosion

During the E&P activities in Sichuan highly sour reservoirs in China, phenomena of elemental sulfur deposition and corrosion were found. Since the characteristic of elemental sulfur depositing on the steel surface has been considered as one of the most important factors controlling the corrosion behavior, much more research work is need to evaluate and predict elemental sulfur corrosion in laboratory by simulating various contact forms between sulfur and steel. This paper will report the effects of test methods and temperature on sulfur corrosion of steel by simulation experiments under different conditions. The forms of sulfur during the tests such as suspending in solution with different content, depositing on the steel surface, paste coverage and molten coverage were investigated in this paper. Different corrosion type and rate can be found among these tests. The rising of the temperature may also change the corrosion type from general corrosion to localized corrosion. Electrochemical tests, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were also employed in order to reveal the formation characteristics of sulfide corrosion product and its effects on the localized corrosion.