Methane hydrate-bearing sediments: Pore habit and implications

by Terzariol, M, Park, J, Castro, G.M, Santamarina, J.C
Article Year: 2020


Terzariol, M., Park, J., Castro, G.M., & Santamarina, J.C.


Hydrate-bearing sediments are relevant to the organic carbon cycle, seafloor instability, and as a potential
energy resource. Sediment characteristics affect hydrate formation, gas migration and recovery strategies. We
combine the physics of granular materials with robust compaction models to estimate effective stress and capillary
pressure in order to anticipate the pore habit of methane hydrates as a function of the sediment characteristics
and depth. Then, we compare these results to an extensive database of worldwide hydrate accumulations
compiled from published studies. Results highlight the critical role of fines on sediments mechanical and
flow properties, hydrate pore habit and potential production strategies. The vast majority of hydrate accumulations
(92% of the sites) are found in fines-controlled sediments at a vertical effective stress between
σ′z = 400 kPa and 4 MPa, where grain-displacive hydrate pore habit prevails in the form of segregated lenses
and nodules. While permeation-based gas recovery by depressurization is favored in clean-coarse sediments, gas
recovery from fines-controlled sediments could benefit from enhanced transmissivity along gas-driven fractures
created by thermal stimulation.


Hydrate accumulation database gas production Methane hydrate pore habit Revised Soil Classification System