Study on the Relative Permeability with Change of Methane Hydrate Saturation in Glass Beads Packs

摘要

Two kinds of glass beads with mean diameters of 110μm and 210μmrnwere used as sediments in which methane hydrate was formed.rnPorosities of these glass beads were determined to be 36.3% and 36.8%rnseparately by a volumetric method. Hydrate saturation was estimatedrnand its relative permeability was measured at different stages ofrnmethane hydrate formation. Results showed that the formation ofrnmethane hydrate in bead packs induces a distinguished decline ofrnpermeability. The relationship can be described as an exponentialrnfunction when the hydrate saturation is under a low value which is notrngreater than 25%. The parallel capillary model of hydrate occupyingrnthe pore center is well fitted with the experimental data. This provedrnthat the methane hydrate was mainly formed in the pores of bead packsrnbut the methane hydrate was not coated on the bead surfaces inrnexperiments.