Dynamics of a microbial community during an effective boost MEOR trial using high-throughput sequencing

Area of Science:

• Microbiology
• Petroleum Engineering
• Environmental Science

Background:

• Microbial Enhanced Oil Recovery (MEOR) is a promising technique for increasing oil extraction from reservoirs.
• Understanding microbial community dynamics is crucial for optimizing MEOR field trials.
• High pour point oil reservoirs present unique challenges for conventional recovery methods.

Purpose of the Study:

• To characterize microbial communities in injection and production waters during an MEOR field trial.
• To assess the impact of nutrient injection on microbial populations in an oil reservoir.
• To provide recommendations for optimizing future MEOR strategies.

Main Methods:

• 454 pyrosequencing of 16S rRNA gene amplicons was used to analyze microbial communities.
• Samples were collected from injection water and production water during a serial MEOR field trial.
• Operational taxonomic units (OTUs) were identified to determine community composition and changes.

Main Results:

• A significant microbial community overlap was observed between injection water and successful MEOR-treated production water (43 shared dominant OTUs).
• Nutrient injection stimulated specific genera (e.g., *Comamonas*, *Pseudomonas*) known for hydrocarbon degradation.
• Microbes predominantly found in production waters showed a significant decrease in abundance post-nutrient injection.

Conclusions:

• The success of the first MEOR round was linked to the compatibility of injection water microbes with reservoir conditions.
• Targeted nutrient optimization is recommended for subsequent MEOR applications, focusing on microbes resilient in both surface and subsurface environments.
• Future MEOR strategies should consider the survival and synergistic capabilities of microbes in diverse environmental conditions.