A contribution of hydrogenotrophic methanogenesis to the biogenic coal bed methane reserves of Southern Qinshui Basin, China

Abstract

The activity of methanogens and related bacteria which inhabit the coal beds is essential for stimulating new biogenic coal bed methane (CBM) production from the coal matrix. In this study, the microbial community structure and methanogenesis were investigated in Southern Qinshui Basin in China, and the composition and stable isotopic ratios of CBM were also determined. Although geochemical analysis suggested a mainly thermogenic origin for CBM, the microbial community structure and activities strongly implied the presence of methanogens in situ. 454 pyrosequencing analysis combined with methyl coenzyme-M reductase (mcrA) gene clone library analysis revealed that the archaeal communities in the water samples from both coal seams were similar, with the dominance of hydrogenotrophic methanogen Methanobacterium. The activity and potential of these populations to produce methane were confirmed by the observation of methane production in enrichments supplemented with H2 + CO2 and formate, and the only archaea successfully propagated in the tested water samples was from the genus Methanobacterium. 454 pyrosequencing analysis also recovered the diverse bacterial communities in the water samples, which have the potential to play a role in the coal biodegradation fueling methanogens. These results suggest that the biogenic CBM was generated by coal degradation via the hydrogenotrophic methanogens and related bacteria, which also contribute to the huge CBM reserves in Southern Qinshui Basin, China.

Biogeochemistry and the associated redox signature of co-produced water from coalbed methane wells in the Shizhuangnan block in the southern Qinshui Basin, China

“…Two metabolic types of methanogenesis have been determined, involving carbon dioxide reduction or acetate fermentation. Guo et al (2014) found that carbon dioxide reduction methanogenesis is dominantly active in the Qinshui Basin. It is generally accepted that carbon dioxide reduction removes 12 C, forming positive d 13 C DIC in remaining formation water (Mori et al, 2012).…”

The effect of NaOH pretreatment on coal structure and biomethane production

“…The coal sample was collected from Sihe coal mine in Qinshui basin, south-central Shanxi province, where biogenic CBM has been found and diverse microbial communities have been detected in the produced water [30]. We state no specific permissions were required for these locations/activities.…”

Enhanced microbial coalbed methane generation: A review of research, commercial activity, and remaining challenges

“…The Proteobacteria represent a vast diversity of bacterial species. However, within coal reservoirs polycyclic-aromatic-hydrocarbon(PAH)-degrading α-Proteobacteria and γ-Proteobacteria, and syntrophic δ-Proteobacteria have been detected and are known to be associated with methanogens (Guo et al, 2012a(Guo et al, , 2014Meslé et al, 2013a;Penner et al, 2010). The dominance of PAH-degrading α-Proteobacteria could reflect in situ physicochemical conditions because PAHs are the main organic compound class detected in CBM produced water samples (Orem et al, 2014).…”