Non-Fickian Diffusion and the Accumulation of Methane Bubbles in Deep-Water Sediments

Abstract

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 thermodiffusion 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.

7 pages, 4 figures

References in corpus (3)

• Diffusive counter dispersion of mass in bubbly media
• Non-Fickian Diffusion Affects the Relation between the Salinity and Hydrate Capacity Profiles in Marine Sediments
• Scaling of Transport Coefficients of Porous Media under Compaction

Cited by in corpus (4)

• Non-Fickian Diffusion Affects the Relation between the Salinity and Hydrate Capacity Profiles in Marine Sediments
• Formation of bubbly horizon in liquid-saturated porous medium by surface temperature oscillation
• Effect of Temperature Wave on Diffusive Transport of Weakly-Soluble Substances in Liquid-Saturated Porous Media
• On thermal diffusion and gauge transformations for thermodynamic fluxes and forces