Carbon steel corrosion in the presence of CO2/ and H2/S (referred to as CO2/H2S corrosion or sour corrosion) is a concern in the oil and gas industry. Chlorides are typically present in the production fluid at a range from parts per million (ppm) for condensed water to tens of percent (%) for produced water. Currently, there is a lack of understanding of the effect of chlorides and/or salinity on sour corrosion.
To gain this understanding, high pressure autoclave testing was carried out to study the effect of chloride concentration on carbon steel sour corrosion. General corrosion rates were measured and corrosion product scales were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Localized/pitting corrosion was evaluated by scanning corroded coupon surfaces after scale removal using an optical profilometer to generate detailed 3D surface profile. This paper will present the experimental results, and discuss the effect of chloride on carbon steel sour general and localized/pitting corrosion.
