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.

A novel material selection method and application in an aqueous environment containing CO2, H2S, O2 and SO2

“…However, in harsh corrosive environments, certain types of carbon steel are highly inapplicable and can undergo rapid corrosion perforation failure in the short term. [4][5][6] The corrosion failure of pipeline materials is a very inevitable and difficult issue, which significantly impacts the secure transportation of oil and gas products. 7 The RL block of an oilfield, for instance, encountered severe corrosion issues and limited applicability of carbon steel materials due to the presence of H 2 S, CO 2 , SO 2 , and O 2 in the pipeline medium.…”