Corrosion testing of X52 and X80 steels immersed in stimulated emulsions using a real petroleum sample

Abstract

The aim of this study is to evaluate the internal corrosion process on X52 and X80 steels/real petroleum interfaces containing condensed hydrocarbon plus oilfield-produced water, which were subjected to stimulated emulsions using 50/50 vol ratio mixtures at 45 °C, different hydrodynamic conditions, 1 h, and 24 h. A washing process by using deionized water was proposed to simulate and identify the corrosiveness of the hydrocarbon phase after 24 h of exposure time. The characterization by electrochemical impedance spectroscopy and the monitoring of the polarization curves indicated that X80 steel/oilfield-produced water interfaces were more susceptible to corrosion than X52 steel exposed to oilfield-produced water. The combined speed rotation of 600 rpm using a magnetic stirrer + 600 rpm using a rotating disk electrode decreased the corrosion rate on X52 steel. The stimulated emulsions made of hydrocarbon + oilfield-produced water and hydrocarbon + deionized water at 24 h increased the corrosion rate on X80 steel (0.34 mm/year and 0.43 mm/year, respectively), promoting the formation of erosion and pitting corrosion. These types of corrosion depended mainly on the physicochemical properties of the hydrocarbon, oilfield-produced water, exposure times, and hydrodynamic systems in which the hydrocarbon was studied.