Managing Internal Corrosion of Mild Steel Pipelines in CO₂‐Enhanced Oil Recovery Multiphase Flow Conditions

Abstract

Abstract The “carbon capture, utilization and storage” project has attracted considerable attention in recent years as the demands for reducing CO 2 emissions increased. However, the produced fluids during CO 2 ‐enhanced oil recovery (EOR) production are supersaturated with high‐pressure CO 2 gas, which leads to serious corrosion damages of the pipelines. To model the corrosive conditions during CO 2 –EOR production, a self‐designed multiphase flow loop for internal corrosion evaluation was built. The role of flow patterns and emulsification that decisively influencing pipeline corrosion was systematically investigated. It was found that a higher gas‐to‐liquid ratio could be beneficial for reducing pipeline corrosion, which was attributed to a reduction in slug frequency and an enhancement in the stirring effect on the oil–brine mixtures. It was also found that corrosion can be completely inhibited if the transporting liquids were properly controlled under water‐in‐oil emulsion condition. A model considering the transport parameters that ensures the safety of crude‐oil transportation is proposed. It suggests that corrosion control by designing the transport parameters would be a suitable and economic method for tackling the corrosion damages to CO 2 –EOR pipelines. These ideas have been accepted for guiding the pipeline engineering in the CO 2 –EOR section of the Shengli oilfield.