In this work, a scalable workflow for field sample preservation, DNA extraction, and quantitative polymerase chain reaction (qPCR) was developed and validated for accurate and rapid oilfield microbial monitoring and microbiologically influenced corrosion (MIC) risk identification. Validation experiments were performed on a variety of challenging oilfield sample types including produced water and pigging sludge to assess the complete optimized qPCR workflow and eight MIC-related qPCR targets including sulfate reducing prokaryotes (SRP) and corrosive methanogens (micH). The predicted in silico taxonomic coverage of these eight MIC-related qPCR targets were compared to a complete microbial community analysis of the samples using 16S rRNA gene sequencing and were found to capture >95% of the taxa present, indicating method reliability for identifying MIC-related microorganisms. The simplified qPCR workflow validated in this work brings qPCR closer to the field to replace or supplement current microbial monitoring practices for higher information yield, ultimately allowing for optimized mitigation strategies and identification of MIC-risk.
Microbiologically influenced corrosion (MIC) is a key risk to oil and gas infrastructure and confers great cost to asset owners. The AMPP 2021 IMPACT Canada study, which analyzed the energy, manufacturing, and mining sectors, shows the cost of corrosion in Canada is roughly $51.9 billion per year [1]. To break this down further, MIC is estimated to make up roughly 20% of all corrosion which is roughly $10.4 billion in Canada alone, each year. When a metal surface such as piping or a storage tank is exposed to even low volumes of water, microorganisms present in the water can attach to surfaces and form large sessile colonies, known as biofilms. Biofilms harbour very diverse microbial communities and the microorganisms present in a biofilm can accelerate corrosion directly or indirectly by a variety of mechanisms. There are several metabolic functional groups known to participate in MIC, which include Sulfate-Reducing Prokaryotes (SRP), Methanogens, Sulfur-Oxidizing Bacteria, Nitrate-Reducing Bacteria, Iron-Reducing Bacteria, Iron-Oxidizing Bacteria, and Acid-Producing Bacteria [2-5].