Microbial diversity in produced water: A comprehensive review

Abstract

Unconventional Oil and Gas operations require large volumes of water to stimulate the production of sequestered hydrocarbons. The water is supplemented with alcohols, surfactants, and biocides. The overall operation generates copious amounts of wastewater known as flowback and produced water. The biogeochemical richness of these oilfield wastewaters provide optimal conditions for the proliferation of different types of microorganisms, particularly bacterial communities. The impact of these microorganisms on hydraulic fracturing operations includes biofilm production, sulfur reduction, petroleum degradation and the corrosion of surface infrastructure. The characterization of the bacterial species present in these waters often requires several analytical techniques including molecular methods and sequencing. To minimize the reliance on fresh water, treatment protocols with sophisticated technologies are employed to eliminate both biological and chemical pollutants from the flowback-produced water and reuse it in hydraulic fracturing. Included is a discussion of the various bacterial communities that have been previously found in hydraulic fracturing wastewater as well as the analytical tools typically employed in their characterization. We also discuss the impact of bacteria found in produced water, the main treatment technologies employed in FPW sanitation, and the current challenges associated to microbial eradication.

Keywords

• Petroleum microbiology
• Bacteria
• Flowback water
• Hydraulic fracturing
• Water reuse