In Oil and Gas (O&G) facilities, it is estimated until a 40% of failures are due to corrosion induced by microorganisms (MIC). These microorganisms remain in planktonic or sessile form and a high diversity of metabolisms can be found. In the present study, planktonic and sessile microbial consortia were isolated and characterized from production waters of unconventional and conventional process. The water production showed major presence of the genus Halanaerobium (94.2%) and Arcobacter (73.6%) in sample of unconventional and conventional processes respectively. In the culture media formulated, Halanaerobium (68%) and genera Desulfovibrio (33.8%), Geotoga (33.3%), Proteiniphilum (30.89%) were found in a higher proportion for unconventional and conventional processes respectively. All these microbial genera have been reported as related to MIC. On the other hand, the biofilm formation was characterized by SEM-EDS and electrochemical techniques, using its ability of MIC in carbon steel; showing that the unconventional microbial consortium slightly higher corrosion capacity (2.35 mm/y) than the conventional microbial consortium (1.25 mm/y). These results represent the synergy of the different metabolisms that interact in the MIC-related communities, such as thiosulfate and sulfate reduction, iron oxidation/reduction and acid production microorganisms in unconventional and conventional processes.
Corrosion causes an annual financial loss of US$4 trillion worldwide, half of that cost is in corrosion prevention and control, the other half in damages and lost productivity1. It is estimated that 20% to 40% of the failures caused by corrosion is produced by MIC2-4. MIC is a type of localized corrosion caused by microbial activities. This includes a variety of processes by which microbes contribute to corrosion directly or indirectly and severely affect the integrity of facilities in various industrial sectors, especially in the O&G industry2,5,6. Biofilms are widely believed to be responsible for MIC, in most cases7,8.
This corrosion mechanism can occur in aqueous environment and is a common problem in O&G facilities due to the ubiquitous nature of microorganisms and corrosives in the pipes. Some facilities that can suffer MIC are water injection lines, storage tanks, sewage treatment systems, filtration systems, pipes, reverse osmosis membranes, and potable water distribution systems4. Secondary recovery processes in mature fields have water cuts greater than 90%, which creates the right conditions for the development of microbial populations due to of their abundant sources of carbon and energy9,10. MIC has also been reported on crude oil and refined products7