Abstract
Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid.
Highlights
Over the last decade, coal bed methane (CBM) has emerged as an important resource for meeting rising global energy demands
Metagenomic datasets averaging 4.1 ± 0.6 Gb of pairedend data were generated for formation waters collected from 11 CBM wells located in the Surat Basin, Queensland, Australia (Figure 1; Table 1)
The PK-28 microbial community was dominated by Operational taxonomic units (OTUs) belonging to the Planctomycetes class Phycisphaerae (9%), the candidate phylum Aminicenantes order OPB95 (11%), the actinobacterial order OPB41 (10%), and hydrogenotrophic methanogens from the family Methanobacteriaceae (11%)
Summary
Coal bed methane (CBM) has emerged as an important resource for meeting rising global energy demands. Our understanding of the microbial communities responsible for the conversion of coal to methane is limited, hampering our ability to engineer strategies for stimulating native microbial communities to produce additional methane. To extract CBM, a vertical well is drilled 200–1000 m into a coal bed. In cases where the natural permeability of the coal does not allow for economical rates of Microbes Enriched by CBM Hydrofracture Additives extraction, stimulation techniques such as hydraulic fracture are commonly applied. A gelling agent, typically a polysaccharide polymer, is commonly included in the hydraulic fracture fluid to suspend the proppant to ensure that it disperses evenly within the seam. Once the fracturing fluid is removed from the well, a production pump is installed at the wellhead to begin dewatering of the CSG well
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
