Investigation of microbiologically influenced corrosion of low alloy steels with different Cr contents in simulated oilfield produced water

Abstract

Microbiologically influenced corrosion has become a predominant cause of pipeline and equipment failure in oil and gas fields. This research examines the corrosion behavior of steels with varying chromium contents in simulated shale gas formation water environments. Weight loss testing, Scanning Electron Microscopy (SEM), Energy Dispersive x-ray Spectroscopy (EDS), Focused Ion Beam (FIB), Transmission Electron Microscopy (TEM), and x-ray Photoelectron Spectroscopy (XPS) were employed. The findings suggest that an elevated Cr content in steel results in a gradual reduction in its uniform corrosion rate in a CO _2 -SRB coexistence environment. This can be primarily attributed to the significant distribution of Cr content throughout the entire product film, including both biofilm and corrosion products, thereby enhancing the product film’s protectiveness. Additionally, the competitive corrosion between CO _2 and SRB, as well as the influence mechanism of Cr on corrosion, were discussed.

Keywords

• CO2 corrosion
• sulfate-reducing bacteria (SRB)
• biofilm
• chromium
• low-Cr steel