Effects of Iron-Oxidizing Bacteria on Carbon Steel in Oilfield Produced Water

Abstract

The effects of iron-oxidizing bacteria (IOB) on the corrosion of carbon steel in oilfield produced water was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), weight loss and electrochemical measurements including open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve measurements. SEM morphologies showed that the biofilm was mainly composed of corrosion products, extracellular polymeric substances (EPS) and little IOB. Additionally, without IOB, the corrosion products were only iron oxides. EIS indicated that the integrity of biofilm on the specimen surface changed with time and the biofilm removed partly at later stage. Potentiodynamic polarization curves indicated that IOB mainly influenced the cathodic process at later stage, and enhanced local corrosion of specimen.