Electrochemical and Gravimetric Study on Corrosion Inhibition of Carbon Steels Exposed to Oilfield Produced Water

Two corrosion inhibitors (CI) were evaluated to study the protection behaviours of three carbon steels: X52, X60, and X70 in an oilfield produced water. The water was subjected to unstirred condition and a rotation speed of 600 rpm to simulate a stagnant and homogeneous solutions, respectively, it is in pipelines at temperature range of 30 degrees C to 60 degrees C. The internal corrosion rate and inhibition efficiencies were measured using polarization curves and gravimetric tests, complimented with the surface analysis of the corroded carbon steel samples using scanning electron microscopy (SEM). The experimental results suggested that the chlorides compounds, H2S, metals, and the inhibitor type modified the corrosion rate of the carbon steels under study. High corrosion rates were achieved on X70 steel at the temperature of 30 degrees C and 50 degrees C under 600 rpm. It was determined that X52 steel had the highest corrosion rate at 60 degrees C and 600 rpm. While an adequate protection of X70 steel was confirmed with a high inhibition efficiency using a naphthenic imidazoline as corrosion inhibitor. Keywords: Inhibitor; pipeline steel; protection; storage tanks.