Microbial controls on the origin and evolution of coal seam gases and production waters of the Walloon Subgroup; Surat Basin, Australia

Baublys, K. A.; Hamilton, Stephanie K.; Golding, Suzanne D.; Vink, Sue; Esterle, Joan

doi:10.1016/j.coal.2015.06.007

Cited by 83 publications

(63 citation statements)

References 44 publications

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“…The enriched δ 13 C-CH 4 value (55.9‰) estimated for the regression line used by Iverach et al 21 to infer CH 4 leakage from the coal measures to the alluvium is within the range of the δ 13 C-CH 4 observed for the deeper gas reservoir (>200 m) sampled in our study (−58‰ to −49‰), and other gas reservoirs in the Surat Basin2728. However, it contrasts with the depleted δ 13 C-CH 4 (−80‰ to −65‰) that we observed for the shallow (<200 m) coal measures that underlie the alluvium.…”

Section: Resultssupporting

confidence: 79%

“…These occur in isolation: under basalt sheetwash near Bowenville (shallow coal measures sample), and on the opposite side of the alluvium near Stratheden (alluvial sample) (see Figs 2 and S2). Acetoclastic methanogenesis has not been observed before in the Walloon Coal Measures in the Surat and Clarence-Moreton basins, although evidence of this pathway has been observed at basin margins in other areas26272941495051. In both cases these samples are found at relatively higher salinity and SO 4 concentrations: for the shallow coal measures sample, Cl = ~1775 mg/L or 50 meq/L, and SO 4 = 480 mg/L or 10 meq/L; for the alluvial sample, Cl = 5990 mg/L or 168 meq/L, and SO 4 = 144 mg/L or 3 meq/L.…”

Section: Resultsmentioning

confidence: 90%

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Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

Owen

Shouakar-Stash²,

Morgenstern

et al. 2016

Sci Rep

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Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (−58‰ to −49‰) and shallow coal measures underlying the alluvium (−80‰ to −65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (<310‰) indicate acetoclastic methanogenesis where SO4 concentrations inhibit CO2 reduction. Evidence of CH4 migration from the deep gas reservoir (200–500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 90%

Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

Owen

Shouakar-Stash²,

Morgenstern

et al. 2016

Sci Rep

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“…Full details on the analytical equipment, procedure and calibration can be found in Baublys et al (2015). For δ 13 C-CH 4 and δ 2 H-CH 4…”

Section: Analysis Of Microbial Communitymentioning

confidence: 99%

Carbon and hydrogen isotope fractionation during methanogenesis: A laboratory study using coal and formation water

Susilawati

Golding

Baublys

et al. 2016

International Journal of Coal Geology

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Carbon and hydrogen isotope compositions of CH 4 generated via methanogenesis in cultures of South Sumatra Basin (SSB) coalbed methane (CBM) formation waters grown on coal, acetate and H 2 +CO 2 were investigated. CH 4 production and molecular analysis confirmed the presence of active microbial communities that are able to convert coal into CH 4 using both acetoclastic and hydrogenotrophic pathways. The representative bacterial sequences were dominated by Bacteroidetes, Firmicutes and Deltaproteobacteria, while Methanosaeta and Methanosarcina were the most prevalent archaeal methanogens present in the cultures.CH 4 produced in this study's culturing experiments has δ 13 C values in the range of -50 ‰ to -20 ‰, with most values falling outside the current understanding of the carbon isotopic boundaries for biogenic CH 4 (-110 ‰ to -30 ‰). However, the corresponding apparent carbon isotopic α factor (α c = 1.02±0.006), and isotopic effect (ε c = -20.1 ‰ ±15.3) showed that CH 4 in SSB cultures was predominantly produced by acetoclastic methanogenesis, which is consistent with the results of molecular DNA analysis. In addition, the calculated contribution of CO 2 reduction from the δ 13 C values of coaltreated cultures was overall < 50 %, further confirming the high contribution of the acetoclastic pathway to CH 4 production in the SSB cultures. The outcome of this experimental study also suggests that δ 2 H-CH 4 values may not provide a reliable basis for distinguishing methanogenic pathways, while apparent carbon isotopic fractionation factor (α c ) and isotope effect (ε c ) are considered more useful indicators of the methanogenic pathway.The high δ 13 C-CH 4 values (>-30 ‰) and the dominance of Methanosaeta over Methanosarcina indicate that methanogens within the SSB cultures were operating at low substrate concentrations. An unusually positive δ 13 C-CH 4 suggests a substrate depletion effect, which is thought to be related to a decrease in the relative abundance of key bacterial coal degraders with formation water inoculum storage time. Closer observation of δ 13 C-CH 4 values during the growth of cultures within a single experiment also showed a 13 C-enrichment trend over time. At log phase of growth, the CH 4 produced was 13 C-depleted when compared to the stationary phase that also indicates substrate depletion effects. Finally, the δ 13 C-CH 4 values encountered in this study (as high as -20 ‰) highlight the possible positive extension of δ 13 C-CH 4 values of acetoclastic methanogenesis from those currently reported in the literature for natural and experimental samples (as high as -30 ‰).Keywords: Biogenic gas, coal, culture experiment, isotopic composition INTRODUCTIONArchaeal methanogens are the only known microorganisms capable of forming CH 4 . These strictly anaerobic microbes are restricted to utilizing simple compounds that contain no more than two carbon atoms. As such, complex organic compounds in anoxic environments (e.g., marine sediments, rice paddies, subsurface shales and coalbeds) ...

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“…Up-dip migration of deeper basinal fluids can also affect CSG producibility via conventional or hydrodynamic trapping and resorption of migrated gases. Employing a combination of stable isotopic and hydrochemical tracers is essential to determine the relative importance of microbial versus thermogenic gas generation, delineating methanogenic pathways and discerning fluid and gas migration directions relative to known reservoir compartmentalisation [11].The eastern Australian CSG industry has experienced significant growth over the last 20 years, prompting several geochemical studies on gas and water origins [1][2][3]9,[13][14][15][16][17][18]. These studies have demonstrated the value of hydrochemistry and stable isotopes as CSG exploration and development tools and enhanced understanding of the low temperature fluid-rock interaction, microbial and mixing processes that occur down to 1000 m in Australia's sedimentary basins.…”

mentioning

confidence: 99%

Controls on Gas Domains and Production Behaviour in A High-Rank CSG Reservoir: Insights from Molecular and Isotopic Chemistry of Co-Produced Waters and Gases from the Bowen Basin, Australia

et al. 2020

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This paper uses hydrochemical and multi-isotope analysis to investigate geological controls on coal seam gas (CSG) saturation domains and gas well production performance in a high-rank (vitrinite reflectance (Rv) > 1.1) CSG field in the north-western Bowen Basin, Australia. New hydrochemical and stable isotope data were combined with existing geochemical datasets to refine hypotheses on the distribution and origins of CSG in two highly compartmentalized Permian coal seams. Stable isotopic results suggest that geographic variations in gas content, saturation and production reflect the extent of secondary microbial gas generation and retention as a function of hydrodynamics. δ 13 C and δ 2 H data support a gas mixing hypothesis with δ 13 C-CH 4 increasing from secondary biogenic values to thermogenic values at depth (δ 13 C −62.2% to −46.3% ), whereas correlated methane and carbon dioxide carbon isotope compositions, ∆ 13 C(CO 2 -CH 4 ) values and δ 13 C DIC /alkalinity trends are largely consistent with microbial CO 2 reduction. In addition, below 200 m, the majority of δ 13 C-CO 2 values are positive (δ 13 C: −1.2% to 7.1% ) and δ 13 C DIC shows an erratic increase with depth for both seams that is characteristic of evolution via microbial activity. The progression of carbon isotope values along the CO 2 reduction fractionation line suggests progressive depletion of the CO 2 reservoir with increasing depth. Faults clearly segment coal seams into areas having significantly different production, with results of geochemical analysis suggesting that pooling of biogenic gas and waters and enhanced methanogenesis occur north of a faulted hinge zone.Geosciences 2020, 10, 74 2 of 25 the life of a field. In shallow CSG plays, areas of higher gas contents, gas saturation and gas production commonly reflect spatial variability in coal bed recharge, hydrodynamics and hydrochemistry along the basin margin, e.g., [9][10][11][12]. The basinward movement of meteoric recharge waters introduces microbes responsible for secondary microbial methane generation, modifies the water chemistry and can cause the migration and accumulation of gases on the up-dip side of structural, stratigraphic or hydrodynamic traps, e.g., structural hinge lines, faults, coal pinch outs, or permeability barriers oriented orthogonal to groundwater flow. Up-dip migration of deeper basinal fluids can also affect CSG producibility via conventional or hydrodynamic trapping and resorption of migrated gases. Employing a combination of stable isotopic and hydrochemical tracers is essential to determine the relative importance of microbial versus thermogenic gas generation, delineating methanogenic pathways and discerning fluid and gas migration directions relative to known reservoir compartmentalisation [11].The eastern Australian CSG industry has experienced significant growth over the last 20 years, prompting several geochemical studies on gas and water origins [1][2][3]9,[13][14][15][16][17][18]. These studies have demonstrated the value of hydrochemistry and ...

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Microbial controls on the origin and evolution of coal seam gases and production waters of the Walloon Subgroup; Surat Basin, Australia

Cited by 83 publications

References 44 publications

Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

Carbon and hydrogen isotope fractionation during methanogenesis: A laboratory study using coal and formation water

Controls on Gas Domains and Production Behaviour in A High-Rank CSG Reservoir: Insights from Molecular and Isotopic Chemistry of Co-Produced Waters and Gases from the Bowen Basin, Australia

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