Microbial communities in Bakken region produced water

Area of Science:

• Environmental microbiology
• Geochemistry
• Petroleum geology

Background:

• The Bakken Shale is a major US oil and gas region.
• Produced water from oil and gas extraction requires characterization.

Purpose of the Study:

• To investigate the microbiology and geochemistry of Bakken produced water.
• To understand microbial community dynamics in this specific environment.

Main Methods:

• Sampling of produced water from 17 well sites over 6 months.
• Analysis of total dissolved solids, dissolved organic carbon, and microbial abundance (16S rRNA gene copies/mL).
• Identification of dominant bacterial orders.

Main Results:

• Produced water exhibited high total dissolved solids (220,000–350,000 mg/L) and low dissolved organic carbon (41–132 mg/L).
• Microbial abundances were low (10^1–10^4 gene copies/mL).
• Bacillales, Halanaerobiales, and Pseudomonadales were the most abundant bacterial orders.
• Temporal shifts in microbial communities were observed, with Halanaerobiales dominating early samples and Bacillales/Pseudomonadales prevalent in later winter samples.

Conclusions:

• This study provides novel insights into Bakken produced water microbiology and chemistry.
• Temporal structuring of microbial communities in hypersaline subsurface fluids was observed.
• Findings contribute to understanding microbial roles in unconventional resource plays.