Flow Influenced Initiation and Propagation of SRB Corrosion on L360N Carbon Steel

Microbiologically influenced corrosion (MIC) often occurs at the bottom of shale gas-gathering pipelines. Under the condition of pipe flow, the synergistic behavior of SRB corrosion and other factors is not clear. Based on the home-made multiphase flow corrosion loop, the biofilm formation and corrosion of sulfate-reducing bacteria on the surface of a shale gas pipeline steel L360N at different liquid flow rates are studied. At low flow rates such as 0.2 m/s and 0.5 m/s, the SRB biofilm gradually thickens. When the flow rate is 1.0 m/s similar to 1.5 m/s, the existing SRB biofilm is stripped. With the increase in velocity, the average and local corrosion rates first increase and then decrease. The synergistic corrosion of MIC and flow rate in the pipe will change with the increase in flow rate. SRB dominated the corrosion of L360N steel at low flow rate. At high velocity, the corrosion of L360N steel is accelerated by flow erosion after the biofilm is stripped. This study clarifies the corrosion behavior of the interaction between SRB and flow rate, and this understanding has rarely been reported in the past literature and can provide a basis for corrosion protection of shale gas field.

Automated summary

The study investigates the biofilm formation and corrosion of sulfate-reducing bacteria on a shale gas pipeline steel at different liquid flow rates. It finds that at low flow rates, the SRB biofilm thickens gradually, while at higher flow rates, the existing biofilm is stripped away leading to accelerated corrosion due to flow erosion. The study provides insights into the synergistic corrosion behavior between SRB and flow rate, which can be valuable for corrosion protection in shale gas fields.