Corrosion Behavior of N80 and 13Cr Steel in Presence of Imidazoline based Inhibitor in Three Different Acid Solutions

In the paper, the corrosion behavior of N80 steel and 13Cr steel pipes caused by common acid liquids (5% HCl, 10% HAC, 10% CA) in oil field was analyzed. The corrosion and corrosion inhibition properties of N80 steel and 13Cr steel in acid solution with or without corrosion inhibitor were studied by electrochemical test and immersion test. The morphology of the corroded steel sheet was observed by scanning electron microscope (SEM). The results show that 13Cr Steel is seriously corroded in HCl solution, and the corrosion in organic acid HAC and CA solution is very low. The N80 steel is severely corroded in both inorganic (HCl) and organic acid (HAC and CA) solutions. The N80 steel and 13Cr steel are mainly pitted and spotted in acid solution. The inconsistency between impedance fitting and corrosion rate shows that the density and adsorption strength of the film have a great influence on the corrosion inhibition efficiency. The research results provide a theoretical basis for acidizing design of oil and gas wells. When the oil casing is Cr steel, HCl solution should be avoided in acidizing of oil and gas wells. The anti-corrosion of oil and gas wells acidification should be optimized from three aspects: steel type, acid type and corrosion inhibitor.