Gas hydrate dissociation affecting the permeability and consolidation behaviour of deep sea host sediment

Marinakis, Dimitris; Varotsis, Nikos; Perissoratis, C.

doi:10.1016/j.jngse.2015.01.012

Cited by 19 publications

(3 citation statements)

References 19 publications

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“…This is about twice as deep than in the cooler global open ocean (Max & Johnson, 2016). Significant NGH deposits also exist beneath the seafloor, and have been identified in the Mediterranean Basin by seismic interpretation and in-situ (De Lange & Brumsack, 1998;Aloisi et al, 2000;Loncke et al, 2004;Pierre & Rouchy, 2004;Dählmann, 2005;Lykousis et al, 2009;Perissoratis et al, 2011;Marinakis et al, 2015), and in the Nile fan (Praeg et al, 2011). Global models of NGH thicknesses indicate a 100 -250 m thick gas hydrate stability zone (GHSZ) in the Mediterranean region (Wood & Jung, 2008) (Fig.…”

Section: Mediterranean Oceanic Natural Gas Hydratementioning

confidence: 98%

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Barnard

Max

Gualdesi³

2017

Medit. Mar. Sci.

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We propose that the source water for some abyssal undular vortices cored by cool, low-salinity water identified at depths in excess of 2,500 m in the deepwater region of the Eastern Mediterranean Basin may be related to conversion of natural gas hydrate (NGH) in abyssal marine sediments. The conditions for extensive formation of NGH in the gas hydrate stability zones (GHSZ) of the upper seafloor sediments existed in this region during previous glacial episodes when colder water supported a thicker GHSZ. Seafloor warming during the most recent interglacial caused thinning of the GHSZ at its base and has driven endothermic NGH dissociation that would have released large volumes of low-salinity water and gas that would tend to pond below the base GHSZ. Periodically, trapped low-salinity water and gas would be released into the sea through the overlying sediments. Buoyant low-salinity water masses, supersaturated with gas and locally containing free gas would ascend and introduce a dynamic element into an otherwise generally static environment. As a result of the interaction of the rise of this buoyant plume and Coriolis acceleration the ascending mass would begin to rotate and form a vortex tube in midwater. NGH conversion within the seafloor introduces large coherent masses of low-salinity, lower-temperature water containing a buoyant free gas fraction from near-surface reservoirs into the abyssal depths even where there may only be a weak natural gas petroleum system.

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Section: Mediterranean Oceanic Natural Gas Hydratementioning

confidence: 98%

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Barnard

Max

Gualdesi³

2017

Medit. Mar. Sci.

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“…Marinakis et al conducted laboratory permeability tests on multicomponent GH formed in pores of treated sediments. Contrary to expectations, the study found that the separation of hydrate had a moderate effect on the permeability of sediments . Kneafsey et al introduced the experimental measurement results of gas permeability in sand and sand–powder mixture in the presence of MH in different states of dry, wet, frozen, and water-bearing .…”

Section: Introductionmentioning

confidence: 99%

“…Contrary to expectations, the study found that the separation of hydrate had a moderate effect on the permeability of sediments. 20 Kneafsey et al introduced the experimental measurement results of gas permeability in sand and sand−powder mixture in the presence of MH in different states of dry, wet, frozen, and water-bearing. 21 By measuring the permeability of water in hydrate-bearing sediments, Li et al found that residual gases become seepage obstacles after hydrate formation.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Evolution of Compressibility and Gas Permeability of Sediments after Hydrate Decomposition under Effective Stress

Zhang

Wang

et al. 2022

Energy Fuels

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The effective stress and types of particles significantly affect the permeability of hydrate sediments. In this study, effects of hydrate saturation, hydrate decomposition, effective stress, and particle type on gas permeability and sample deformation of montmorillonite samples and quartz-montmorillonite mixtures were investigated. The results showed that the gas phase permeability increased with hydrate formation. In addition, the decline of sample porosity is the fundamental factor determining the permeability failure rate under effective stress. During methane hydrate decomposition by depressurization, the compression coefficient of samples increases with decreasing pore pressure, which means that decomposing natural gas hydrate makes experimental samples more sensitive to stress. Furthermore, the addition of sand particles significantly affects the compressibility of sediments. In addition, because of the decline of sample porosity and the swelling of montmorillonite, the results of gas permeability show a downward trend when the pore pressure decreases during the decomposition of methane hydrate. Gas permeability of the sample ranges from a few millidarcies to several hundred millidarcies. Furthermore, the content of clay and the particle size in the sample are the key factors in determining the permeability damage rate when the stress increases during decomposition of methane hydrate. Therefore, the addition of quartz sand can reduce damage of gas permeability of sediments caused by effective stress and hydrate decomposition.

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Stratigraphic Sequence and Sedimentary Systems in the Middle-Southern Continental Slope of the East China Sea from Seismic Reflection Data: Exploration Prospects of Gas Hydrate

Chen

et al. 2019

J. Ocean Univ. China

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Gas hydrate dissociation affecting the permeability and consolidation behaviour of deep sea host sediment

Cited by 19 publications

References 19 publications

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Submarine vortices derived from natural gas hydrate conversion: a mechanism for ocean mixing

Experimental Study on the Evolution of Compressibility and Gas Permeability of Sediments after Hydrate Decomposition under Effective Stress

Stratigraphic Sequence and Sedimentary Systems in the Middle-Southern Continental Slope of the East China Sea from Seismic Reflection Data: Exploration Prospects of Gas Hydrate

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