Ameaça Biocorrosiva: monitoramento da biocorrosão e diagnóstico metagenômico em campos de extração de petróleo

Abstract

A corrosion influenced by microorganisms (CIM) is a significant issue in oil fields, accounting for 10 to 20% of failures that occur. Predicting and monitoring this process is challenging due to the variability of biofilms within industrial systems and their susceptibility to localized corrosion, which is harder to monitor compared to uniform corrosion, presenting several challenges. Thus, this study proposed a metagenomic technological package for oil field monitoring that is practical and applicable in routine processes. The systematic review showed that the microbial community composition in evaluated oil regions includes groups capable of various types of metabolism, such as syntrophic, oxidative, and production of corrosive metabolites, depending on the physicochemical characteristics of the environment. In the standardization tests of DNA extraction methods, the specific commercial kit for soil DNA extraction proved superior in terms of yield, purity, and DNA integrity compared to other commercial kits evaluated in produced water and oil samples. The 16S rRNA amplicon approach was more efficient in detecting organisms with abundances above 1%, compared to shotgun sequencing, and revealed coherent metabolic pathways with the produced water environment in oil fields, making it the best option for monitoring in this context. The adapted low-cost protocol from Yu & Morrison (2004) was capable of obtaining satisfactory quality DNA, resulting in high-quality Phred sequencing, suitable for monitoring in the oil industry. We also observed that 16S rRNA amplicon sequencing applied to DNA directly extracted from the environment (metagenomic samples), combined with physicochemical characterization, provides a more accurate representation in monitoring microbial groups in oil industry facilities, compared to application in communities enriched with specific culture media for CIM groups. Finally, the monitoring of pipelines used for transporting petroleum products and waste indicated that the predominant form of corrosion observed was pitting corrosion, possibly caused by acid-producing bacteria (APBs) that predominantly utilize the 1,2-propanediol degradation metabolism. We conclude that the DNA extraction methods developed in this thesis are applicable and represent significant advances in routine monitoring of microbiologically influenced corrosion (CIM) in the oil industry.