Permeability is known as a key factor affecting the gas production effectiveness from the natural hydrate reservoir. The formation and dissociation processes of gas hydrate in the sediments also have an influence on the permeability. In this study, samples from hydrate reservoir in Qilian Mountain permafrost were taken for the measurement of permeability changes before hydrate formation, with hydrate and also after hydrate dissociation. An unexpected permeability decrease was observed after the dissociation of methane hydrate, which was explained as the “reservoir formation damage”. Permeability variation is also related to hydrate saturation in the sediments.
Keywords Gas Hydrate; Reservoir Formation Damage; Hydrate Dissociation; Gas Production