Synergistic Effect of Factors Influencing the External Corrosion of Heavy Oil Pipelines in Reed Pond Soil

Abstract

At present, the transportation environment of heavy oil pipelines is complex and subject to a specific set of factors. However, external corrosion problems are inevitable. In this work, the corrosion rate, corrosion morphology and corrosion products of 16Mn heavy oil pipeline steel in the reed pond soil of the Liaohe oilfield were studied by immersion experiments and SEM, EDS and XRD analysis methods. Based on the gray correlation analysis method, the effect of five factors influencing the corrosion rate of 16Mn steel in a reed pond soil environment was discussed by utilizing dynamic potential polarization and AC impedance technology. The analysis of potential dynamic polarization and AC impedance technology shows that the corrosion rate gradually increases due to the decrease in pH and the increase in temperature and concentration of the corrosive anions Cl−, SO42− and HCO3− in the environment. The order of the correlation between influencing corrosion factors and the corrosion rate of 16Mn steel is as follows: temperature > Cl− > SO42− > HCO3− > pH value.