Performance of Imidazolium Inhibitors in Highly Chloride-containing Oilfield Solution

The corrosion inhibition performance and mechanism of two inhibitors containing benzimidazole and 6-nitrobenzoimidazole on Q235 steel in highly chloride-containing oilfield solution were studied for providing guidance of inhibitor choice in oilfield environments.The inhibitor additions in oilfield solution containing chloride was studied by weight loss method and electrochemical methods.The results showed that the two kinds of corrosion inhibitors all had significant inhibition efficiency on Q235 steel.The inhibition efficiency increased with the increase of inhibitor concentration.Benzimidazole inhibition effects was the best when its concentration was 1.0 g/L,and the inhibition efficiency reached 90.41%.And the inhibition efficiency reached 84.78% with 6-Nitrobenzimidazole concentration of 0.5 g/L.Results obtained from polarization and EIS were in good agreement with those from weight loss method.Inhibition efficiency of benzimidazole was greatly higher than that of 6-Nitrobenzimidazole,the adsorption of benzimidazole and 6-Nitrobenzoimidazole on the Q235 steel surface was a spontaneous process,which obeyed Langmuir adsorption isotherm model.