PHYSICAL PROPERTIES OF HYDRATE-BEARINGSEDIMENTS

摘要

Methane gas hydrates, crystalline inclusion compoundsformed from methane and water, are found in marinecontinental margin and permafrost sediments worldwide.This article reviews the current understanding ofphenomena involved in gas hydrate formation and thephysical properties of hydrate-bearing sediments. Formationphenomena include pore-scale habit, solubility, spatialvariability, and host sediment aggregate properties. Physicalproperties include thermal properties, permeability, electricalconductivity and permittivity, small-strain elastic P and Swave velocities, shear strength, and volume changes resulting from hydrate dissociation. The magnitudes andinterdependencies of these properties are critically importantfor predicting and quantifying macroscale responses ofhydrate-bearing sediments to changes in mechanical,thermal, or chemical boundary conditions. Thesepredictions are vital for mitigating borehole, local, andregional slope stability hazards; optimizing recoverytechniques for extracting methane from hydrate-bearingsediments or sequestering carbon dioxide in gas hydrate;and evaluating the role of gas hydrate in the global carboncycle.