oa Microbial Communities in FPW and Their Potential Role in CO2 Mineralization: A Review

Flowback and produced waters (FPW) from unconventional oil and gas operations host diverse microbial communities that can contribute to in situ CO2 biomineralization—a process in which microorganisms precipitate CO2 as stable carbonate minerals.

Bacterial classification in FPW follows taxonomic or functional approaches. While taxonomy provides structural insight, functional grouping is critical for assessing microbes’ role in CO2 biomineralization, as it directly relates to their carbon cycling and mineralizing activities.

FPW bacterial communities vary considerably depending on formation age, lithology, and operational factors. Nonetheless, many identified taxa exhibit biomineralization potential. For example, flowback water from the Paleozoic Bakken and Barnett shales is dominated by Proteobacteria and Firmicutes, while produced waters from the Denver-Julesburg (DJ) Basin—which spans Paleozoic to Cenozoic strata—are enriched in Actinobacteria. All three phyla have demonstrated the ability to precipitate CO2 as carbonate minerals under appropriate geochemical conditions.

Harnessing FPW for microbial CO2 sequestration presents a dual advantage: these waters contain both indigenous microbial populations and dissolved cations necessary for mineralization. Moreover, biologically mediated CO2 sequestration is potentially less energy-intensive than traditional chemical approaches. Integrating this biomineralization strategy into subsurface operations offers a sustainable and cost-effective path for carbon management within the energy sector.