GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2020-2024  (14)
  • 2005-2009  (6)
Document type
Keywords
Publisher
Language
Years
Year
  • 1
    Online Resource
    Online Resource
    Methane sources, distributions, and fluxes from cold vent sites at Hydrate Ridge, Cascadia Margin (2005)
    Associated volumes
    Details Availability
    In: Global biogeochemical cycles, Hoboken, NJ : Wiley, 1987, 19(2005), 1944-9224
    In: volume:19
    In: year:2005
    In: extent:21
    Type of Medium: Online Resource
    Pages: 21 , graph. Darst
    ISSN: 1944-9224
    DOI: 10.1029/2004GB002266
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GEOMAR CATALOGUE
    Link to Library Catalog
    get availability status
  • 2
    Online Resource
    Online Resource
    Methane sources feeding cold seeps on the shelf and upper continental slope off central Oregon, USA (2009)
    Associated volumes
    Details Availability
    In: Geochemistry, geophysics, geosystems, Hoboken, NJ : Wiley, 2000, 10(2009), 11, 1525-2027
    In: volume:10
    In: year:2009
    In: number:11
    In: extent:21
    Description / Table of Contents: We report on a bathymetric mapping and remotely operated vehicle surveys along the 100600 m region offshore Oregon from 43ʿ50?N to 44°18'N. We interpret our results in light of available geophysical data, published geotectonic models, and analogous observations of fluid venting and carbonate deposition from 44°30'N to 45°00'N. The methane seepage is defined by juxtaposition of a young prism, where methane is generated by bacterial activity and its release is modulated by gas hydrate dynamics, against older sequences that serve as a source of thermogenic hydrocarbons that vent in the shelf. We hypothesize that collision of a buried ridge with the Siletz Terrane results in uplift of gas hydrate bearing sediments in the oncoming plate and that the resulting decrease in pressure leads to gas hydrate dissociation and methane exolution, which, in turn, may facilitate slope failure. Oxidation of the released methane results in precipitation of carbonates that are imaged as high backscatter along a 550 ± 60 m benthic corridor.
    Type of Medium: Online Resource
    Pages: 21 , Ill., graph. Darst
    ISSN: 1525-2027
    URL: http://www.agu.org/journals/gc/gc0911/2009GC002518/
    DOI: 10.1029/2009GC002518
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GEOMAR CATALOGUE
    Link to Library Catalog
    get availability status
  • 3
    Online Resource
    Online Resource
    In situ hydrocarbon concentrations from pressurized cores in surface sediments, northern Gulf of Mexico (2007)
    Associated volumes
    Details Availability
    In: Marine chemistry, Amsterdam [u.a.] : Elsevier Science, 1972, 107(2007), 4, Seite 498-515, 0304-4203
    In: volume:107
    In: year:2007
    In: number:4
    In: pages:498-515
    Description / Table of Contents: Two newly developed coring devices, the Multi-Autoclave-Corer and the Dynamic Autoclave Piston Corer were deployed in shallow gas hydrate-bearing sediments in the northern Gulf of Mexico during research cruise SO174 (Oct- Nov 2003). For the first time, they enable the retrieval of near-surface sediment cores under ambient pressure. This enables the determination of in situ methane concentrations and amounts of gas hydrate in sediment depths where bottom water temperature and pressure changes most strongly influence gas/hydrate relationships. At seep sites of GC185 (Bush Hill) and the newly discovered sites at GC415, we determined the volume of low-weight hydrocarbons (C1 through C5) from nine pressurized cores via controlled degassing. The resulting in situ methane concentrations vary by two orders of magnitudes between 0.031 and 0.985 mol kg -1 pore water below the zone of sulfate depletion. This includes dissolved, free, and hydrate-bound CH4. Combined with results from conventional cores, this establishes a variability of methane concentrations in close proximity to seep sites of five orders of magnitude. In total four out of nine pressure cores had CH4 concentrations above equilibrium with gas hydrates. Two of them contain gas hydrate volumes of 15% (GC185) and 18% (GC415) of pore space. The measurements prove that the highest methane concentrations are not necessarily related to the highest advection rates. Brine advection inhibits gas hydrate stability a few centimeters below the sediment surface at the depth of anaerobic oxidation of methane and thus inhibits the storage of enhanced methane volumes. Here, computerized tomography (CT) of the pressure cores detected small amounts of free gas. This finding has major implications for methane distribution, possible consumption, and escape into the bottom water in fluid flow systems related to halokinesis.
    Type of Medium: Online Resource
    Pages: Ill., graph. Darst
    ISSN: 0304-4203
    DOI: 10.1016/j.marchem.2007.08.008
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GEOMAR CATALOGUE
    Link to Library Catalog
    get availability status
  • 4
    facet.materialart.
    Unknown
    Development, test, and evaluation of exploitation technologies for the application of gas production from natural gas hydrate reservoirs and their potential application in the Danube Delta, Black Sea (2020)
    Elsevier
    Details
    Publication Date: 2023-02-08
    Description: Highlights • The SUGAR project has developed and tested various methods for gas production from marine gas hydrates from micro to field scale. • Numerical simulations improved the understanding of processes on molecular to reservoir scale. • Depressurization is a promising technology for exploiting gas hydrate deposits in the Danube Delta. • The injection of CO2 or CO2–N2 is not a suitable method for the exploitation of gas hydrate deposits in the Danube Delta. Abstract One important scientific objective of the national research project SUGAR – Submarine Gas Hydrate Reservoirs was the development, improvement, and test of innovative concepts for the production of methane from natural gas hydrate reservoirs. Therefore, different production methods, such as the thermal stimulation using in situ combustion, the chemical stimulation via injection of CO2 as a gaseous, liquid or supercritical phase and depressurization were tested alone or in combination at different scales. In the laboratory experiments these ranged from pore and hydrate grain scale to 425-L reactor volume, whereas numerical models were applied to describe the related processes from molecular to reservoir scale. In addition, the numerical simulations also evaluated the feasibility and efficiency of the application of these methods in selected areas, such as the Danube Paleodelta in the Black Sea, addressing the two dominant methane hydrate reservoir settings, buried channel-levee and turbidite systems. It turned out, that the injection of CO2 or a CO2–N2 gas mixture is not applicable for the Danube Paleodelta in the Black Sea, because the local pressure and temperature conditions are too close to the equilibrium conditions of both, the CO2 hydrate and a CO2–N2 mixed hydrate stability fields. Experiments using thermal stimulation and depressurization showed promising results but also some issues, such as sufficient heat transfer. In summary it can be said that the applicability and efficiency of each method has to be proven for each specific hydrate reservoir conditions. Based on the results obtained by numerical simulations the most promising and safe method for the production of CH4 from hydrate bearing sediments in the Danube Paleodelta would be the depressurization technique. This study summarizes the main experimental and modeling results.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
    facet.materialart.
    Unknown
    Methane sources, distributions, and fluxes from cold vent sites at Hydrate Ridge, Cascadia Margin (2005)
    AGU (American Geophysical Union)
    In:  Global Biogeochemical Cycles, 19 . GB2016.
    Details
    Publication Date: 2018-03-16
    Description: To constrain the fluxes of methane (CH4) in the water column above the accretionary wedge along the Cascadia continental margin, we measured methane and its stable carbon isotope signature (δ13C-CH4). The studies focused on Hydrate Ridge (HR), where venting occurs in the presence of gas-hydrate-bearing sediments. The vent CH4 has a light δ13C-CH4 biogenic signature (−63 to −66‰ PDB) and forms thin zones of elevated methane concentrations several tens of meters above the ocean floor in the overlying water column. These concentrations, ranging up to 4400 nmol L−1, vary by 3 orders of magnitude over periods of only a few hours. The poleward undercurrent of the California Current system rapidly dilutes the vent methane and distributes it widely within the gas hydrate stability zone (GHSZ). Above 480 m water depth, the methane budget is dominated by isotopically heavier CH4 from the shelf and upper slope, where mixtures of various local biogenic and thermogenic methane sources were detected (−56 to −28‰ PDB). The distribution of dissolved methane in the working area can be represented by mixtures of methane from the two primary source regions with an isotopically heavy background component (−25 to −6‰ PDB). Methane oxidation rates of 0.09 to 4.1% per day are small in comparison to the timescales of advection. This highly variable physical regime precludes a simple characterization and tracing of “downcurrent” plumes. However, methane inventories and current measurements suggest a methane flux of approximately 3 × 104 mol h−1 for the working area (1230 km2), and this is dominated by the shallower sources. We estimate that the combined vent sites on HR produce 0.6 × 104 mol h−1, and this is primarily released in the gas phase rather than dissolved within fluid seeps. There is no evidence that significant amounts of this methane are released to the atmosphere locally.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1029/2004GB002266
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
    facet.materialart.
    Unknown
    In-situ hydrocarbon concentrations from pressurized cores in surface sediments, Northern Gulf of Mexico (2007)
    Elsevier
    In:  Marine Chemistry, 107 (4). pp. 498-515.
    Details
    Publication Date: 2017-08-22
    Description: Two newly developed coring devices, the Multi-Autoclave-Corer and the Dynamic Autoclave Piston Corer were deployed in shallow gas hydrate-bearing sediments in the northern Gulf of Mexico during research cruise SO174 (Oct–Nov 2003). For the first time, they enable the retrieval of near-surface sediment cores under ambient pressure. This enables the determination of in situ methane concentrations and amounts of gas hydrate in sediment depths where bottom water temperature and pressure changes most strongly influence gas/hydrate relationships. At seep sites of GC185 (Bush Hill) and the newly discovered sites at GC415, we determined the volume of low-weight hydrocarbons (C1 through C5) from nine pressurized cores via controlled degassing. The resulting in situ methane concentrations vary by two orders of magnitudes between 0.031 and 0.985 mol kg− 1 pore water below the zone of sulfate depletion. This includes dissolved, free, and hydrate-bound CH4. Combined with results from conventional cores, this establishes a variability of methane concentrations in close proximity to seep sites of five orders of magnitude. In total four out of nine pressure cores had CH4 concentrations above equilibrium with gas hydrates. Two of them contain gas hydrate volumes of 15% (GC185) and 18% (GC415) of pore space. The measurements prove that the highest methane concentrations are not necessarily related to the highest advection rates. Brine advection inhibits gas hydrate stability a few centimeters below the sediment surface at the depth of anaerobic oxidation of methane and thus inhibits the storage of enhanced methane volumes. Here, computerized tomography (CT) of the pressure cores detected small amounts of free gas. This finding has major implications for methane distribution, possible consumption, and escape into the bottom water in fluid flow systems related to halokinesis.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.marchem.2007.08.008
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
    facet.materialart.
    Unknown
    Production Method under Surveillance: Laboratory Pilot-Scale Simulation of CH 4 –CO 2 Exchange in a Natural Gas Hydrate Reservoir (2021)
    ACS (American Chemical Society)
    Details
    Publication Date: 2024-02-07
    Description: The "guest exchange"of methane (CH4) by carbon dioxide (CO2) in naturally occurring gas hydrates is seen as a possibility to concurrently produce CH4 and sequester CO2. Presently, process evaluation is based on CH4-CO2 exchange yields of small-or medium-scale laboratory experiments, mostly neglecting mass and heat transfer processes. This work investigates process efficiencies in two large-scale experiments (210 L sample volume) using fully water-saturated, natural reservoir conditions and a gas hydrate saturation of 50%. After injecting 50 kg of heated CO2 discontinuously (E1) and continuously (E2) and a subsequent soaking period, the reservoir was depressurized discontinuously. It was monitored using electrical resistivity, temperature and pressure sensors, and fluid flow and gas composition measurements. Phase and component inventories were analyzed based on mass and volume balances. The total CH4 production during CO2 injection was only 5% of the initial CH4 inventory. Prior to CO2 breakthrough, the produced CH4 roughly equaled dissolved CH4 in the produced pore water, which balanced the volume of the injected CO2. After CO2 breakthrough, CH4 ratios in the released CO2 quickly dropped to 2.0-0.5 vol %. The total CO2 retention was the highest just before the CO2 breakthrough and higher in E1 where discontinuous injection improved the distribution of injected CO2 and subsequent mixed hydrate formation. The processes were improved by the succession of CO2 injection by controlled degassing at stability limits below that of the pure CH4 hydrate, particularly in experiment E2. Here, a more heterogeneous distribution of liquid CO2 and larger availability of free water led to smaller initial degassing of liquid CO2. This allowed for quick re-formation of mixed gas hydrates and CH4 ratios of 50% in the produced gases. The experiments demonstrate the importance of fluid migration patterns, heat transport, sample inhomogeneity, and secondary gas hydrate formation in water-saturated sediments.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
    facet.materialart.
    Unknown
    (Table 1) Analysis of pore water (PW) and hydrocarbon gases (HC) on sediment samples after degassing, and the recovery pressure (pressure) on SO174 samples (2007)
    PANGAEA
    Details
    Publication Date: 2023-07-10
    Keywords: 152; 153; 158; 166; 170; Analysis; Bush Hill; Center for Marine Environmental Sciences; DAPC; Device type; Dynamic autoclave piston corer; Elevation of event; Event label; Latitude of event; Location type; Longitude of event; MAC; MARUM; Multi autoclave corer; OTEGA II; Pressure, water; Sample, optional label/labor no; SO174/1; SO174/1_118; SO174/1_63; SO174/1_90; SO174/1_97; SO174/2; SO174/2_152; SO174/2_153; SO174/2_158; SO174/2_166; SO174/2_170; Sonne
    Type: Dataset
    Format: text/tab-separated-values, 42 data points
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 9
    facet.materialart.
    Unknown
    Methane sensor (METS) measurements at station HE537_58-1 (2020)
    PANGAEA
    Details
    Publication Date: 2024-01-12
    Description: Deep-towed methane and CTD data measured during RV Heincke expedition HE537 in the German 'Entenschnabel' area, North Sea. The methane sensor (METS) from the company Franatech was mounted at a frame (together with CTD, video cameras, forward looking sonar, altimeter and USBL transponder), which was towed 0.5 - 2 m above the sea floor at tow speeds of only 0.5 - 1 knots.
    Keywords: ALTITUDE; Center for Marine Environmental Sciences; Conductivity; DEPTH, water; HE537; HE537_58-1; Heincke; LATITUDE; LONGITUDE; MARUM; MESSAGER; Methane; North Sea; Ocean Floor Observation System; OFOS; Temperature, gas; Temperature, water; Time of day
    Type: Dataset
    Format: text/tab-separated-values, 39795 data points
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 10
    facet.materialart.
    Unknown
    Methane sensor (METS) measurements at station HE537_69-1 (2020)
    PANGAEA
    Details
    Publication Date: 2024-01-12
    Description: Deep-towed methane and CTD data measured during RV Heincke expedition HE537 in the German 'Entenschnabel' area, North Sea. The methane sensor (METS) from the company Franatech was mounted at a frame (together with CTD, video cameras, forward looking sonar, altimeter and USBL transponder), which was towed 0.5 - 2 m above the sea floor at tow speeds of only 0.5 - 1 knots.
    Keywords: ALTITUDE; Center for Marine Environmental Sciences; Conductivity; DEPTH, water; HE537; HE537_69-1; Heincke; LATITUDE; LONGITUDE; MARUM; MESSAGER; Methane; North Sea; Ocean Floor Observation System; OFOS; Temperature, gas; Temperature, water; Time of day
    Type: Dataset
    Format: text/tab-separated-values, 50975 data points
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...