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dc.contributor.authorChatterjee, Sayantan
Bhatnagar, Gaurav
Dugan, Brandon
Dickens, Gerald R.
Chapman, Walter G.
Hirasaki, George J.
dc.date.accessioned 2014-09-05T20:26:37Z
dc.date.available 2014-09-05T20:26:37Z
dc.date.issued 2014
dc.identifier.citation Chatterjee, Sayantan, Bhatnagar, Gaurav, Dugan, Brandon, et al.. "The impact of lithologic heterogeneity and focused fluid flow upon gas hydrate distribution in marine sediments." Journal of Geophysical Research: Solid Earth, 119, (2014) American Geophysical Union: http://dx.doi.org/10.1002/2014JB011236.
dc.identifier.urihttps://hdl.handle.net/1911/77147
dc.description.abstract Gas hydrate and free gas accumulation in heterogeneous marine sediment is simulated using a two-dimensional (2-D) numerical model that accounts for mass transfer over geological timescales. The model extends a previously documented one-dimensional (1-D) model such that lateral variations in permeability (k) become important. Various simulations quantitatively demonstrate how focused fluid flow through high-permeability zones affects local hydrate accumulation and saturation. Simulations that approximate a vertical fracture network isolated in a lower permeability shale (kfracture >> kshale) show that focused fluid flow through the gas hydrate stability zone (GHSZ) produces higher saturations of gas hydrate (25–70%) and free gas (30–60%) within the fracture network compared to surrounding shale. Simulations with a dipping, high-permeability sand layer also result in elevated saturations of gas hydrate (60%) and free gas (40%) within the sand because of focused fluid flow through the GHSZ. Increased fluid flux, a deep methane source, or both together increase the effect of flow focusing upon hydrate and free gas distribution and enhance hydrate and free gas concentrations along the high-permeability zones. Permeability anisotropy, with a vertical to horizontal permeability ratio on the order of 10−2, enhances transport of methane-charged fluid to high-permeability conduits. As a result, gas hydrate concentrations are enhanced within these high-permeability zones. The dip angle of these high-permeability structures affects hydrate distribution because the vertical component of fluid flux dominates focusing effects. Hydrate and free gas saturations can be characterized by a local Peclet number (localized, vertical, focused, and advective flux relative to diffusion) relative to the methane solubility gradient, somewhat analogous to such characterization in 1-D systems. Even in lithologically complex systems, local hydrate and free gas saturations might be characterized by basic parameters (local flux and diffusivity).
dc.language.iso eng
dc.publisher American Geophysical Union
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
dc.title The impact of lithologic heterogeneity and focused fluid flow upon gas hydrate distribution in marine sediments
dc.type Journal article
dc.contributor.funder U.S. Department of Energy
dc.citation.journalTitle Journal of Geophysical Research: Solid Earth
dc.subject.keywordgas hydrate
focused fluid flow
lithologic heterogeneity
permeability conduits
local fluid flux
numerical modeling
dc.citation.volumeNumber 119
dc.type.dcmi Text
dc.identifier.doihttp://dx.doi.org/10.1002/2014JB011236
dc.identifier.grantID DE-FC26-06NT42960 (U.S. Department of Energy)
dc.type.publication publisher version


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