A Mathematical Model for Dissociation of Gas Hydrate

摘要

This paper presents a model for natural gas hydrate dissociation fromthe methane hydrate reservoir by depressurization or temperaturefallingof the well. In this model, the controlling equations are consistedof quality conservation, momentum equilibrium and energyconservation equations. Four media: Free methane (gas), methanehydrate (solid), rock skeleton, and water (liquid) are in thermodynamicequilibrium. The heat suction by the dissociation and the convectionconductionare considered also. The geological formation is assumed tobe uniform and the flow of free methane is regarded as flow through aporous media with porosity. It is shown that the dissociation rateincreases with the increase of depressurization and the increase ofinitial saturation of gas hydrate and degrades fast with the distancefrom the boundary. The changes of the pressure on the boundary havelarge effects on the dissipation of the pore pressure. The changes of theheat conductivity have little effects on the dissociation of gas hydrateand the dissipation of pore pressure.