Abstract
Influence of methane hydrate on permeability of hosting sediments is
critical to understand natural hydrate formation and gas production. A
few conceptual models proposed to explain the influence of hydrate could
not recapitulate the actual hydrate pore habits and distribution with
the overly-simplified geometric assumptions used in those models. This
study simulates single phase flow through hydrate-bearing sediments with
a numerical approach to explore influences of hydrate on fluid flow,
based on real 3D pore structures of methane hydrate-bearing sediments
obtained via micro-CT scans. Pore-scale analysis and observations show
(1) hydrate particles, at low hydrate saturation, protrude into the flow
channels and efficiently inhibit the flow; (2) at high saturation or in
small pores, hydrate particles block some pores and pores without
hydrate determine permeability. Influence of intra-pore habit on
permeability is not obvious; by contrast, inter-pore distribution of
hydrate has a higher impact and can cause drastic permeability
anisotropy.