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Berlin Brandenburg

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  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 04 December 2018, Vol.115(49), pp.12349-12358
    Description: Extensive development of shale gas has generated some concerns about environmental impacts such as the migration of natural gas into water resources. We studied high gas concentrations in waters at a site near Marcellus Shale gas wells to determine the geological explanations and geochemical implications. The local geology may explain why methane has discharged for 7 years into groundwater, a stream, and the atmosphere. Gas may migrate easily near the gas wells in this location where the Marcellus Shale dips significantly, is shallow (∼1 km), and is more fractured. Methane and ethane concentrations in local water wells increased after gas development compared with predrilling concentrations reported in the region. Noble gas and isotopic evidence are consistent with the upward migration of gas from the Marcellus Formation in a free-gas phase. This upflow results in microbially mediated oxidation near the surface. Iron concentrations also increased following the increase of natural gas concentrations in domestic water wells. After several months, both iron and SO concentrations dropped. These observations are attributed to iron and SO reduction associated with newly elevated concentrations of methane. These temporal trends, as well as data from other areas with reported leaks, document a way to distinguish newly migrated methane from preexisting sources of gas. This study thus documents both geologically risky areas and geochemical signatures of iron and SO that could distinguish newly leaked methane from older methane sources in aquifers.
    Keywords: Hydraulic Fracturing ; Methane ; Noble Gases ; Shale Gas ; Water Quality
    ISSN: 00278424
    E-ISSN: 1091-6490
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Language: English
    In: US Petroleum & Gas, Dec 3, 2018, p.7(1)
    Description: Extensive development of shale gas has generated some concerns about environmental impacts such as the migration of natural gas into water resources. We studied high gas concentrations in waters at a site near Marcellus Shale gas wells to determine the geological explanations and geochemical implications. The local geology may explain why methane has discharged for 7 years into groundwater, a stream, and the atmosphere. Gas may migrate easily near the gas wells in this location where the Marcellus Shale dips significantly, is shallow (~1 km), and is more fractured. Methane and ethane concentrations in local water wells increased after gas development compared with predrilling concentrations reported in the region. Noble gas and isotopic evidence are consistent with the upward migration of gas from the Marcellus Formation in a free-gas phase. This upflow results in microbially mediated oxidation near the surface. Iron concentrations also increased following the increase of natural gas concentrations in domestic water wells. After several months, both iron and S042- concentrations dropped. These observations are attributed to iron and S042- reduction associated with newly elevated concentrations of methane. These temporal trends, as well as data from other areas with reported leaks, document a way to distinguish newly migrated methane from preexisting sources of gas. This study thus documents both geologically risky areas and geochemical signatures of iron and S042- that could distinguish newly leaked methane from older methane sources in aquifers.
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
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  • 3
    In: US Petroleum & Gas, Nov 26, 2018, p.6(1)
    Description: Extensive development of shale gas has generated some concerns about environmental impacts such as the migration of natural gas into water resources. We studied high gas concentrations in waters at a site near Marcellus Shale gas wells to determine the geological explanations and geochemical implications. The local geology may explain why methane has discharged for 7 years into groundwater, a stream, and the atmosphere. Gas may migrate easily near the gas wells in this location where the Marcellus Shale dips significantly, is shallow (~1 km), and is more fractured. Methane and ethane concentrations in local water wells increased after gas development compared with predrilling concentrations reported in the region. Noble gas and isotopic evidence are consistent with the upward migration of gas from the Marcellus Formation in a free-gas phase. This upflow results in microbially mediated oxidation near the surface. Iron concentrations also increased following the increase of natural gas concentrations in domestic water wells. After several months, both iron and S042- concentrations dropped. These observations are attributed to iron and S042- reduction associated with newly elevated concentrations of methane. These temporal trends, as well as data from other areas with reported leaks, document a way to distinguish newly migrated methane from preexisting sources of gas. This study thus documents both geologically risky areas and geochemical signatures of iron and S042- that could distinguish newly leaked methane from older methane sources in aquifers.
    Keywords: Aquifers ; Methane ; Natural Gas ; Shale Oils ; Groundwater ; Water Resources
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
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  • 4
    Language: English
    In: Environmental science & technology, 12 July 2019
    Description: Methane (CH) enters waters in hydrocarbon-rich basins because of natural processes and problems related to oil and gas wells. As a redox-active greenhouse gas, CH degrades water or emits to the atmosphere and contributes to climate change. To detect if methane migrated from hydrocarbon wells (i.e., anomalous methane), we examined 20 751 methane-containing groundwaters from the Upper Appalachian Basin (AB). We looked for concentrations (mg/L) that indicated AB brine salts (chloride concentrations ([Cl]) 〉 30; [Ca]/[Na] 〈 0.52) to detect natural methane, and we looked for concentrations of redox-active species ([SO] ≥ 6; [Fe] ≥ 0.3) to detect anomalous methane. These indicators highlight natural contamination by methane-containing brines or recent onset of microbial oxidation of methane coupled to iron- or sulfate-reduction. We hypothesized that only waters recently contaminated by methane still exhibit high iron and sulfate concentrations. Of the AB samples, 17 (0.08%) from 12 sites indicated potential contamination. All were located in areas with high densities of shale-gas or conventional oil/gas wells. In contrast, in southwestern Pennsylvania where brines are shallow and coal, oil, and gas all have been extracted extensively, no sites of recent methane migration were detectable. Such indicators may help screen for contamination in some areas even without predrill measurements.
    Keywords: Wells ; Contamination ; Hydrocarbons ; Water Wells ; Salts ; Iron ; Hydrocarbons ; Methane ; Oxidation ; Brines ; Iron ; Greenhouse Gases ; Indicators ; Climate Change ; Salt Water ; Oxidation ; Sulfate Reduction ; Sulfate Reduction ; Greenhouse Gases ; Oxidation ; Basins ; Methane ; Groundwater ; Greenhouse Effect ; Groundwater Chemistry ; Sulfates ; Oil ; Microorganisms ; Organic Chemistry ; Change Detection ; Sulfate Reduction ; Greenhouse Effect ; Iron ; Gas Wells ; Shale Gas ; Methane ; Brines ; Groundwater ; Brines ; Basins ; Greenhouse Gases ; Shale ; Oil ; Contamination;
    ISSN: 0013936X
    E-ISSN: 1520-5851
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 5
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