Air Foam Flooding Aerobic Corrosion Mechanism And Prevention And Control Technology Research

The corrosion behaviors of pipeline steel in the produced water of oilfield were investigated using electrochemical impedance spectra?EIS?,TaFel plot and linear sweeping plot.The influences of accompanying gas,temperature,Ca²⁺/Mg²⁺cation ions,S^2-anion ions,Cl^-anion ions,time on the corrosion behavior were also studied.The results showed that the pipeline steel eroded heavily in the stratum water containing oxygen,and the corrosion rate increased exponentially with the increased oxygen.The corrosion scale appeared loosen structure,in which Fe-oxidation and ferric hydroxide were the major component,and the protection of the corrosion scale on the substrate was limited.The corrosion rate of pipeline steel in the stratum water containing CO₂+O₂ increased with the increment of oxygen.The corrosion rate of pipeline steel in the stratum water containing CO₂+N₂ decreased with increasing nitrogen.Temperature,Ca²⁺/Mg²⁺ions,Cl^-ions,S^2-ions,time have remarkable effect on the corrosion rate of pipeline steel in the stratum water.The corrosion rate increased with increasing temperature,S^2-and Cl^-ions.While the corrosion rate decreased with increasing Ca²⁺/Mg²⁺ions.And the corrosion rate initially decreased and then it increased with increasing corrosion time.The corrosion rate increased with increasing oxygen in the stratum water containing O₂+CO₂+N₂ with one fixed CO₂ content.However,the corrosion rate decreased with increasing oxygen in the stratum water containing O₂+CO₂+N₂ with one fixed O₂ content.The nickel-based alloy,such as G3,Inconel600,Monel 40 and Monel K500,can effectively prevent the occurrence of oxygen corrosion,and the corrosion rates of G3 and Inconel 600 alloy are the most smaller as far,and they can become the candidate of the pipeline steel.Finally,the invented coating can also decrease the corrosion of pipeline steel.