Insight into polymer concentration, temperature, CO2 content, and Cl− content on corrosion of N80 steel tubing in polymer flooding

Abstract The corrosion of N80 steel in polymer flooding is studied, and the safe service life of N80 steel tubing is calculated. The results show that the temperature is the main factor affecting the corrosion of tubing during the process of polymer flooding, and the safe service life of N80 carbon steel tubing at 75°C is only 11.1 years. The polymer is connected by molecular chains to form a network structure and then adsorbed on the surface of the steel. As the polymer concentration increases, the space between polymer molecules becomes smaller; the exposed surface area decreases; and the corrosion rate of N80 steel decreases. Both temperature and Cl − ions destroy the adsorption capacity of the polymer on the carbon steel substrate. The negatively charged chloride ion repels the negatively charged polymer, leading to the resolution of the polymer and reduction of the corrosion inhibition of the polymer. High temperature destroys the polymer's intramolecular and intermolecular aggregation, and also wrecks the long molecular chain polymer structure, significantly inhibiting the corrosion inhibition effect of the polymer.