Comparison of fluid geochemistry and microbiology of multiple organic-rich reservoirs in the Illinois Basin, USA: Evidence for controls on methanogenesis and microbial transport

Schlegel, Melissa E.; McIntosh, Jennifer C.; Bates, Brittney L.; Kirk, Matthew F.; Martini, Anna M.

doi:10.1016/j.gca.2011.01.016

Cited by 89 publications

(74 citation statements)

References 52 publications

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“…6c). This result is consistent with what has been observed in deeper coalbed methane and organic-rich shale microbial gas systems (Schlegel et al, 2011). These observations are consistent with the redox ladder concept and are further illustrated in Fig.…”

Section: Redox-sensitive Parameters and The Distribution Of Methane Isupporting

confidence: 92%

Redox controls on methane formation, migration and fate in shallow aquifers

Humez¹,

Mayer²,

Nightingale³

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish (a) natural in situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. This study combines aqueous and gas (dissolved and free) geochemical and isotope data from 372 groundwater samples obtained from 186 monitoring wells of the provincial Groundwater Observation Well Network (GOWN) in Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. We investigated whether methane occurring in shallow groundwater formed in situ, or whether it migrated into the shallow aquifers from elsewhere in the stratigraphic column. It was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of biogenic methane ( > 0.01 mM or > 0.2 mg L −1 ), characterized by δ 13 C CH 4 values < −55 ‰, occurred in anoxic Na-Cl, Na-HCO 3 , and Na-HCO 3 -Cl type groundwaters with negligible concentrations of nitrate and sulfate suggesting that methane was formed in situ under methanogenic conditions for 39.1 % of the samples. In only a few cases (3.7 %) was methane of biogenic origin found in more oxidizing shallow aquifer portions suggesting limited upward migration from deeper methanogenic aquifers. Of the samples, 14.1 % contained methane with δ 13 C CH 4 values > −54 ‰, potentially suggesting a thermogenic origin, but aqueous and isotope geochemistry data revealed that the elevated δ 13 C CH 4 values were caused by microbial oxidation of biogenic methane or postsampling degradation of low CH 4 content samples rather than migration of deep thermogenic gas. A significant number of samples (39.2 %) contained methane with predominantly biogenic C isotope ratios (δ 13 C CH 4 < −55 ‰) accompanied by elevated concentrations of ethane and sometimes trace concentrations of propane. These gases, observed in 28.1 % of the samples, bearing both biogenic (δ 13 C) and thermogenic (presence of C 3 ) characteristics, are most likely derived from shallow coal seams that are prevalent in the Cretaceous Horseshoe Canyon and neighboring formations in which some of the groundwater wells are completed. The remaining 3.7 % of samples were not assigned because of conflicting parameters in the data sets or between replicates samples. Hence, despite quite variable gas concentrations and a wide range of δ 13 C CH 4 values in baseline groundwater samples, we found no conclusive evidence for deep thermogenic gas migration into shallow aqu...

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Section: Redox-sensitive Parameters and The Distribution Of Methane Isupporting

confidence: 92%

Redox controls on methane formation, migration and fate in shallow aquifers

Humez¹,

Mayer²,

Nightingale³

et al. 2016

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…Similarly, dissolved inorganic carbon (δ 13 C-DIC) signatures were reportedly good indicators of the infiltration of produced CSG waters into adjacent systems (Sharma and Frost, 2008;Sharma and Baggett, 2011). This is due to the prevalence of enriched δ 13 C-DIC values in organic-rich systems where methanogenesis occurs, because this biogenic process preferentially removes the lighter 12 C isotope from water (Schlegel et al, 2011). Some authors also used an integrated approach considering both hydrochemistry and isotopes to infer the degree of inter-aquifer mixing in different CSG settings (Grossman et al, 1989;Frost et al, 2011;Hofmann and Cartwright, 2013;Kanduč et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

Duvert

Raiber

Owen

et al. 2015

Applied Geochemistry

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“…The occurrence of methanogenesis and the predominance of one or another of the methanogenic pathways in the environment may depend on a combination of factors such as temperature, CO 2 concentrations, salinity, pH, availability of electron acceptors and donors and nutrients, porosity and permeability, for example [Dolfing et al, 2008;Kotsyurbenko et al, 2007;Mayumi et al, 2011;Milkov, 2011;Schlegel et al, 2011;Siegert et al, 2011;Waldron et al, 2007]. From the distribution of biodegraded oils worldwide, it seems that reservoirs buried to temperatures of more than 80 ° C are effectively sterilized with regard to hydrocarbon degraders [Head et al, 2003;Wilhelms et al, 2001].…”

Section: Methanogenic Hydrocarbon Degradationmentioning

confidence: 99%

“…Archaeal communities are often less abundant than bacteria [Jiménez et al, 2012;Orphan et al, 2000] and usually less diverse, with just a few predominant operational taxonomic units [Schlegel et al, 2011]. Orphan et al [2000] reported only a minor presence of archaeal clones in 16S rRNA gene clone libraries from production water from a high-temperature oil field in California.…”

Section: Microbial Ecology and Molecular Biology Of Methanogenic Hydrmentioning

confidence: 99%

Methanogenic Hydrocarbon Degradation: Evidence from Field and Laboratory Studies

et al. 2016

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Microbial transformation of hydrocarbons to methane is an environmentally relevant process taking place in a wide variety of electron acceptor-depleted habitats, from oil reservoirs and coal deposits to contaminated groundwater and deep sediments. Methanogenic hydrocarbon degradation is considered to be a major process in reservoir degradation and one of the main processes responsible for the formation of heavy oil deposits and oil sands. In the absence of external electron acceptors such as oxygen, nitrate, sulfate or Fe(III), fermentation and methanogenesis become the dominant microbial metabolisms. The major end product under these conditions is methane, and the only electron acceptor necessary to sustain the intermediate steps in this process is CO₂, which is itself a net product of the overall reaction. We are summarizing the state of the art and recent advances in methanogenic hydrocarbon degradation research. Both the key microbial groups involved as well as metabolic pathways are described, and we discuss the novel insights into methanogenic hydrocarbon-degrading populations studied in laboratory as well as environmental systems enabled by novel cultivation-based and molecular approaches. Their possible implications on energy resources, bioremediation of contaminated sites, deep-biosphere research, and consequences for atmospheric composition and ultimately climate change are also addressed.

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Comparison of fluid geochemistry and microbiology of multiple organic-rich reservoirs in the Illinois Basin, USA: Evidence for controls on methanogenesis and microbial transport

Cited by 89 publications

References 52 publications

Redox controls on methane formation, migration and fate in shallow aquifers

Redox controls on methane formation, migration and fate in shallow aquifers

Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

Methanogenic Hydrocarbon Degradation: Evidence from Field and Laboratory Studies

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