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Variations in pockmark composition at the Vestnesa Ridge: Insights from marine controlled source electromagnetic and seismic data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-10)
The Vestnesa Ridge marks the northern boundary of a known submarine gas hydrate province in the west Svalbard margin. Several seafloor pockmarks at the eastern segment of the ridge are sites of active methane venting. Until recently, seismic reflection data were the main tool for imaging beneath the ridge. Coincident controlled source electromagnetic (CSEM), high‐resolution two‐dimensional (2‐D) ...
An integrated view of the methane system in the pockmarks at Vestnesa Ridge, 79°N
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-08)
The Vestnesa Ridge is a NW-SE trending, ~ 100 km-long, 1–2 km-thick contourite sediment section located in the Arctic Ocean, west of Svalbard, at 79°N. Pockmarks align along the ridge summit at water depths of ~ 1200 m; they are ~ 700 m in diameter and ~ 10 m deep relative to the surrounding seafloor. Observations of methane seepage in this area have been reported since 2008. Here we summarize and ...
3D Seismic Investigation of a Gas Hydrate and Fluid Flow System on an Active Mid‐Ocean Ridge; Svyatogor Ridge, Fram Strait
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-12)
Tectonic settings play a large role in the development of fluid flow pathways for gas migrating through sedimentary strata. Many gas hydrate systems worldwide are located on either passive continental margins, in large contourite deposits on the slopes of passive continental margins or on subduction margins. The Svyatogor Ridge, however, located at the northwestern flank of the Knipovich Ridge and ...
Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-16)
Carbon capture and storage (CCS) activities at the Snøhvit field, Barents Sea, will involve carrying out an analysis to determine which parameters affect the migration process of CO2 from the gas reservoir, to what degree they do so and how sensitive these parameters are to any changes. This analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir, fault and gas ...
Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-23)
We have estimated the seismic attenuation in gas hydrate and free-gas-bearing sediments from high-resolution
P-cable 3D seismic data from the Vestnesa Ridge on the Arctic continental margin of Svalbard. P-cable
data have a broad bandwidth (20–300 Hz), which is extremely advantageous in estimating seismic attenuation in
a medium. The seismic quality factor (Q), the inverse of seismic attenuation, ...
Hydrate occurrence in Europe: A review of available evidence
(Journal article; Tidsskriftartikkel, 2019-08-16)
Large national programs in the United States and several Asian countries have defined and characterised their marine methane hydrate occurrences in some detail, but European hydrate occurrence has received less attention. The European Union-funded project “Marine gas hydrate – an indigenous resource of natural gas for Europe” (MIGRATE) aimed to determine the European potential inventory of exploitable ...
High-resolution 3D seismic study of pockmarks and shallow fluid flow systems at the Snøhvit hydrocarbon field in the SW Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-21)
The Barents Sea is an epicontinental shelf sea with a fragmented structure consisting of long fault complexes, basins and basement highs. Fluid leakage from deep-seated hydrocarbon accumulations is a widespread phenomenon and mostly related to its denudation history during the glacial/interglacial cycles. In this study, we aimed to better understand shallow fluid flow processes that have led to the ...
Microseismicity linked to gas migration and leakage on the western Svalbard shelf
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-26)
The continental margin off Prins Karls Forland, western Svalbard, is characterized by widespread
natural gas seepage into the water column at and upslope of the gas hydrate stability zone. We
deployed an ocean bottom seismometer integrated into the MASOX (Monitoring Arctic Seafloor-Ocean
Exchange) automated seabed observatory at the pinch-out of this zone at 389 m water depth to investigate
passive ...
Modelling persistent methane seepage offshore western Svalbard since early Pleistocene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-31)
Recent observations of extensive methane release into the oceans and atmosphere have raised
concern as to whether rising temperatures across the Arctic could drive rapid destabilization
of gas hydrate reservoirs. Here, we report modelling results from hydrate-modulated methane
seepage from Vestnesa Ridge, offshore western Svalbard, suggesting that continuous leakage
has occurred from the seafloor ...
In Situ Temperature Measurements at the Svalbard Continental Margin: Implications for Gas Hydrate Dynamics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-30)
During expedition MARIA S. MERIAN MSM57/2 to the Svalbard margin offshore Prins Karls Forland, the seafloor drill rig MARUM‐MeBo70 was used to assess the landward termination of the gas hydrate system in water depths between 340 and 446 m. The study region shows abundant seafloor gas vents, clustered at a water depth of ∼400 m. The sedimentary environment within the upper 100 m below seafloor (mbsf) ...