Gas liquid-carried flow accelerates MIC by sulfate reducing bacteria biofilm

Abstract

The corrosion and perforation leakage of shale gas pipelines can lead to serious environmental damage. By tracking the water and gas components throughout the shale gas production cycle, the main factors that affect corrosion in shale gas pipelines have been identified: carbon dioxide, dissolved oxygen, sulfate-reducing bacteria, and chloride ions. The study focused on understanding the development mechanism of localized corrosion of L360N steel within the upward shale gas gathering pipeline, particularly under the combined influence of sulfate-reducing bacteria and flowing conditions. SRB could form a biofilm on the surface of the steel. Through the Dissimilatory Sulfate Reduction (DSR) process, the metabolites reacted with Fe2+ to produce FeS. The corrosion rate of L360N steel was observed to be higher when exposed to gas-liquid flow compared to static conditions. In the flowing state, the boundary layer within the upward pipeline exhibited backflow tendencies, causing a portion of the corrosion products and biofilm to peel off. This exposure revealed a local surface, acting as an anode. As a result, corrosion pits were further deepened due to microscopic eddy currents, indicating that zero net liquid flow accelerated the corrosion process.