Abstract
The microbial induced corrosion (MIC) is a very dangerous process, which affects the oil industry, particularly the hydrocarbons extraction, transport and storage. The activity and microorganisms growth at the pipelines steel cause surface modifications, which can induced a more complex corrosion process. MIC evaluation has been normally based upon microbiological tests, and just a few references mention alternating methods, such as electrochemical techniques, which can be used as criteria for their evaluation.In this work, different electrochemical laboratory techniques were used, in order to determine the corrosion behavior of a microbial consortium, obtained from the Atasta - Nohoch gas transporting pipeline, in the southeast of Mexico. The bacteria population growth was found to be different for sessile and plancktonic microorganisms. Moreover, long incubation times were required to reach the maximum concentration of sessile bacteria. The electrochemical techniques used in this study: EN and PR, exhibited a similar tendency on the corrosion rate behaviour with time, and values above 0.3 mmy were observed at the end of the experiments. The experiments were complemented with surface analysis. Scanning electron microscope observation of APIXL52 steel coupons, exposed to the consortium action, revealed bacteria presence, as well as a damaged steel surface. A type of localized corrosion was observed on the metal surface, and it was associated to the bacteria effect.
