Effects of Permeability on Spatial Distribution of Hydrate Saturation and Gas Production Performance during Hydrate Dissociation by Depressurization around Quadruple Point

摘要

Permeability is critical for gas production from the methane hydratesediment and spatial distribution of hydrate saturation during hydratedissociation via depressurization around quadruple point especially. Thenumerical model of hydrate dissociation coupling ice formation kineticswas developed and verified by comparing and analyzing theexperimental and simulation results. Further, the spatial distribution ofhydrate saturation and gas production performance were investigated. Asa result, depressurization below quadruple point, the extent of hydratesaturation dissociation around the perforation of well are enhanced withthe decreasing permeability at the same degree of hydrate dissociationwhile the differences in the out wall are not clear. The spatialdistributions of hydrate saturation present the uniform mode rather thana sharp dissociation front as in cases of ice generation. A higher reservoirpermeability resulted in an earlier peak gas generation time and a higherpeak gas generation rate. Ice would generate and release additional heatfor hydrate dissociation especially in the condition of adiabatic boundary.