Scaling of Transport Coefficients of Porous Media under Compaction

TL;DR

This paper derives scaling laws for how the transport properties of fluid-saturated porous sediments change with compaction and porosity, highlighting their importance for modeling geological systems like methane hydrate deposits.

Contribution

It introduces new scaling laws for sediment compaction and evaluates their impact on transport properties in nonuniform geological systems.

Findings

Transport properties depend on porosity and compaction.

Uniform geothermal gradient assumptions are inadequate for nonuniform systems.

Scaling laws are crucial for modeling methane hydrate deposits.

Abstract

Porous sediments in geological systems are exposed to stress by the above-laying mass and consequent compaction, which may be significantly nonuniform across the massif. We derive scaling laws for the compaction of sediments of similar geological origin. With these laws, we evaluate the dependence of the transport properties of a fluid-saturated porous medium (permeability, effective molecular diffusivity, hydrodynamic dispersion, electrical and thermal conductivities) on its porosity. In particular, we demonstrate that the assumption of a uniform geothermal gradient is not adequate for systems with nonuniform compaction and show the importance of the derived scaling laws for mathematical modelling of methane hydrate deposits; these deposits are believed to have potential for impact on global climate change and Glacial-Interglacial cycles.