Laboratory investigation of microbiologically influenced corrosion of carbon steel in hydrotest using enriched artificial seawater inoculated with an oilfield biofilm consortium

Abstract

Abstract Microbiologically Influenced Corrosion (MIC) is a major concern in hydrotest using untreated water. The hydrotesting process itself may last only hours, but the hydrotest water is often shut in for weeks or months. This allows biofilms to grow on pipe walls, which may eventually lead to pinhole leaks after the pipeline is commissioned. This laboratory study investigated MIC in hydrotest using an oilfield biofilm consortium to inoculate enriched artificial seawater to simulate hydrotest fluid. C1018 carbon steel coupons were placed in 120\u202fmL anaerobic vials for incubation at 37\u202f°C for up to 60\u202fdays. Experimental results showed that sulfate reducing bacteria (SRB), general heterotrophic bacteria (GHB) and acid producing bacteria (APB) formed robust biofilms on coupons that led to a weight loss of 7.1\u202f±\u202f0.3\u202fmg/cm2 and maximum pit depth of 33.5\u202fμm after 60\u202fdays. Electrochemical measurements were found to be consistent with the corrosion data.