Metabolic Capability of a Predominant Halanaerobium sp. in Hydraulically Fractured Gas Wells and Its Implication in Pipeline Corrosion

Abstract

Microbial activity associated with produced water from hydraulic fracturing operations can lead to gas souring and corrosion of carbon-steel equipment. We examined the microbial ecology of produced water and the prospective role of the prevalent microorganisms in corrosion in a gas production field in the Barnett Shale. The microbial community was mainly composed of halophilic, sulfidogenic bacteria within the order Halanaerobiales, which reflected the geochemical conditions of highly saline water containing sulfur species (S2O32-, SO42-, and HS-). A predominant, halophilic bacterium (strain DL-01) was subsequently isolated and identified as belonging to the genus Halanaerobium. The isolate could degrade guar gum, a polysaccharide polymer used in fracture fluids, to produce acetate and sulfide in a 10% NaCl medium at 37°C when thiosulfate was available. To mitigate potential deleterious effects of sulfide and acetate, a quaternary ammonium compound was found to be an efficient biocide in inhibiting the growth and metabolic activity of strain DL-01 relative to glutaraldehyde and tetrakis (hydroxymethyl) phosphonium sulfate. Collectively, our findings suggest that predominant halophiles associated with unconventional shale gas extraction could proliferate and produce sulfide and acetate from the metabolism of polysaccharides used in hydraulic fracturing fluids. These metabolic products might be returned to the surface and transported in pipelines to cause pitting corrosion in downstream infrastructure.

Comparative genomics and physiology of the genus Methanohalophilus, a prevalent methanogen in hydraulically fractured shale

“…Methanohalophilus is a prevalent member of persisting microbial communities in hydraulically fractured unconventional reservoirs Given the potential economic importance of methane producing archaea to the recovery of natural gas from unconventional reservoirs, we surveyed publicly available sequencing data (single gene and metagenomic) from produced fluids for the presence of methanogens (Table 1). We combined data from prior published reports spanning five different unconventional energy plays, both from our group (Daly et al, 2016;Borton et al, 2018) and other studies (Waldron et al, 2007;Struchtemeyer et al, 2011;Davis et al, 2012;Fichter et al, 2012;Wuchter et al, 2013;Murali Mohan et al, 2013a;Murali Mohan et al, 2013b;Cluff et al, 2014;Akob et al, 2015;Tucker et al, 2015;Liang et al, 2016;Lipus et al, 2016). We also include new (previously unpublished) data from the STACK play in Oklahoma (deposited in NCBI Bioproject #PRJNA308326).…”

“…Microorganisms injected into natural‐gas wells invariably have an impact on the deep biosphere environment. The metabolic activity of some persistent microorganisms in unconventional reservoirs can lead to sulfide production, resulting in souring and infrastructure corrosion (Liang et al, ; Booker et al, ), while the accumulation of microbial biomass may lead to clogging of fractures (Elsner and Hoelzer, ). Other persistent microbial community members include methane producing archaea, which could have a positive impact on energy yields.…”

Predominance and Metabolic Potential of Halanaerobium spp. in Produced Water from Hydraulically Fractured Marcellus Shale Wells

“…Previous studies have investigated the microbial ecology of Marcellus Shale produced water, reporting a rapid transition of the microbial community in produced water from an aerobic surface water microbial community to a fermentative, anaerobic community (6,7,10,13,14). Notably, bacteria of the genus Halanaerobium (order Halanaerobiales) have been shown to be predominant members of the produced water microbial community (6,10,(13)(14)(15), representing a potential operational concern due to its fermentative (16)(17)(18)(19), thiosulfate-reducing (15,(19)(20)(21)(22) nature. Previous taxonomic characterization of microbial communities in produced water from the Marcellus Shale was performed on the basis of a sum total of six wells, with a maximum of three per study, all less than 18 months following fracture (6,7,10,13,14,23,81).…”

How to access and exploit natural resources sustainably: petroleum biotechnology

“…Several studies have observed that hydraulic fracturing creates favourable conditions for microbial growth in shales, despite the use of biocides. Predominantly halotolerant and methanogenic microbial communities have been identified, which play a role in methylamine cycling, methanogenesis, sulfur cycling and fermentation of some of the injected chemical additives (Cluff et al, 2014;Daly et al, 2016;Liang et al, 2016). Recently, in a large metagenomics study of produced fluids from the Marcellus Shale, Pennsylvania, a new genus was identified, Candidatus Frackibacter (Daly et al, 2016).…”

“…Such microbial metabolisms can lead to gas souring and corrosion of carbon-steel equipment in the industry. The study subsequently investigated biocides to inhibit the growth and metabolic activity of the microorganisms, in order to mitigate the deleterious effects of the sulfide (Liang et al, 2016). Investigations into microbemineral interactions within the fractures may be a future strategy to manipulate the porosity and permeability of the shale matrix through microbially mediated mineral precipitation or dissolution as a means to exploit the shale gas resource (Head and Gray, 2016).…”