The purpose of this study is to address the severe corrosion of L245 carbon steel in CO2-O2 coexistence environments within oil and gas fields. Therefore, a strategy involving the formation of a dual-layer film (oxide film + inhibitor film) on the L245 carbon steel surface is proposed.
A double-layer film with an outer hydrogen barrier layer and an inner oxygen-resistant layer [oxide film/3-mercapto-1,2,4-triazole (MTZ) corrosion inhibitor] was designed. The weight loss method, electrochemical tests, surface morphology analysis and molecular dynamics simulation were adopted to evaluate its performance in a 2 Wt.% sodium chloride solution, and the underlying mechanism was investigated.
The double-layer film showed excellent protective performance in CO2–O2 coexisting environment. Molecular dynamics simulation verified that MTZ inhibitor had stronger adsorption affinity on iron oxide than on iron.
The double-layer film composed of the inner oxide film and the outer MTZ corrosion inhibitor film can achieve the dual effects of blocking H + and resisting O2.
