Inhibition of carbon steel corrosion in model stratum waters containing hydrogen sulfide

The protective effectiveness of the product with the composition "Phosphated salts of amines, esters, reaction products of fatty acids with amines, quaternary salts, ethylene glycols, alcohols" was studied in relation to hydrogen sulfide corrosion of carbon steel in model stratum waters of oil and gas fields. The study was carried out by the gravimetry, potentiodynamic polarization and impedance spectroscopy methods. According to gravimetric data, the protective efficacy of the inhibitory composition at a concentration of 200 mg/L is 92% in the NACE medium and 81% in M1 medium containing 400 mg/L H2S under static conditions. Under hydrodynamic conditions in the presence of a hydrocarbon phase (10%), the protective effect is 10% lower. According to polarization measurements, the inhibitory composition predominantly inhibits the cathodic process. The results of impedance measurements confirm the slowdown of the corrosion process with an increase in the concentration of the inhibitory composition and indicate the adsorption of its components on the metal surface. The coverage of the electrode surface with adsorbed substances and the value of the free energy of adsorption were calculated. The inhibitory composition reduces the diffusion of hydrogen through a steel membrane in the NACE medium containing 400 mg/L H2S. Received: March 16, 2023. Published: April 4, 2023 doi: 10.17675/2305-6894-2023-12-2-2