https://doi.org/10.1140/epje/i2014-14045-x
Regular Article
Non-Fickian diffusion and the accumulation of methane bubbles in deep-water sediments
1
Department of Mathematics, University of Leicester, LE1 7RH, Leicester, UK
2
Department of Geology, University of Leicester, LE1 7RH, Leicester, UK
3
Institute of Continuous Media Mechanics, UB RAS, 614013, Perm, Russia
4
British Geological Survey, NG12 5GG, Nottingham, UK
5
School of Earth and Environment, University of Leeds, LS2 9JT, Leeds, UK
* e-mail: Denis.Goldobin@gmail.com
Received:
26
December
2013
Revised:
13
April
2014
Accepted:
30
April
2014
Published online:
30
May
2014
In the absence of fractures, methane bubbles in deep-water sediments can be immovably trapped within a porous matrix by surface tension. The dominant mechanism of transfer of gas mass therefore becomes the diffusion of gas molecules through porewater. The accurate description of this process requires non-Fickian diffusion to be accounted for, including both thermal diffusion and gravitational action. We evaluate the diffusive flux of aqueous methane considering non-Fickian diffusion and predict the existence of extensive bubble mass accumulation zones within deep-water sediments. The limitation on the hydrate deposit capacity is revealed; too weak deposits cannot reach the base of the hydrate stability zone and form any bubbly horizon.
Key words: Topical issue: Thermal nonequilibrium phenomena in multicomponent fluids
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2014