Corrosion Behavior of Pipeline Steel in Oilfield Produced Water under Dynamic Corrosion System

In order to predict the corrosion trendency of X100 pipeline steel in flowing oilfield produced water, the effect of flow rate on the corrosion behavior of X100 pipeline steel was studied under general dynamic condition and simulated real working condition at the flow rate of 0.2, 0.4, and 0.6 m·s−1. Potentiodynamic polarization curves and electrochemical impedance spectroscopy were used to study the corrosion behavior of X100 steel. Energy dispersive spectroscopy, X-ray diffraction and scanning electron microscopy were used to analyze corrosion product composition and micromorphology. The experimental results show that the corrosion is more serious under simulated real working conditions than that under the general dynamic conditions. In any case the corrosion current density increases with the increase of the flow rate, and the total impedance value decreases. The corrosion products include Fe3O4, Fe2O3, and FeOOH. The mass transfer and electrochemistry were simulated by flow coupled in COMSOL software. The multiphysical field coupling simulation results are closer to the engineering practice than the single flow field simulation, and similar results from the experiments were obtained. Both experimental and simulation results reveal that the higher flow rate is, the more serious corrosion appear and the more corrosion products accumulate. By combining experimental and COMSOL simulation data, the corrosion process model of X100 steel was proposed.