An Integrated Processing Technology of Corrosion Inhibition and Iron Removal for Oilfield Injection Sewage

The effect of ferrous ion content on the viscosity of injection solution with polymer was systematically analyzed. The existence of ferrous ions in sewage was calculated based on the density functional theory. The additive WZ-1 for corrosion inhibition and iron removal was developed as a target, and was applied to the treatment of sewage in Shengli oilfield. The results show that ferrous ion decreased the viscosity of injection solution with polymer. The most stable coordination state of ferrous ion was 6 coordination compound which was composed of one ferrous ion, two water molecules and four chloride ions. The additive WZ-1 for corrosion inhibition and iron removal had excellent effect for iron removal and good corrosion inhibition to carbon steel. Ferrous ions could be completely removed from the sewage by only adding 20 mg/L additive WZ-1, and the inhibition efficiency was close to 90%. The viscosity of injection solution with polymer could be improved more than 20% when 20% additive WZ-1 was added into injection sewage, showing a good stability.