Effect of Acid Corrosion Inhibitors on the Corrosion Performance of Sectional Completion Tubing

The types and thermogravimetric characteristics of corrosion inhibitors were analyzed using infrared spectroscopy (IR) and thermogravimetric analysis (TGA). The corrosion behavior of Inconel 718 nickel-based alloy and sulfur-resistant steel P110SS in fresh acid solutions containing different concentrations of corrosion inhibitors, as well as the galvanic corrosion behavior of the coupled materials, were investigated through weight loss and electrochemical methods. Scanning electron microscopy (SEM) was employed to observe the corrosion morphology of the materials after exposure. The results demonstrate that under individual material conditions, the corrosion rate of P110SS in fresh acid decreases gradually with increasing inhibitor concentration, while the nickel-based alloy remains largely unaffected. When Inconel 718 and P110SS are coupled in a “large cathode, small anode” configuration, the galvanic corrosion rate increases with the area ratio. Corrosion inhibitors effectively suppress galvanic corrosion by inhibiting the cathodic process of the galvanic pair and reducing the galvanic corrosion rate.