Methane Hydrate Formation in Porous Media

Abstract

It is known that methane hydrate formation has mainly been studied by stirring in homogeneous systems such as autoclave systems. To simulate methane hydrate formation in porous media new heterogeneous experimental models were designed, and by their use, the hydrate formation without stirring in porous media such as glassbeads and Berea sandstone cores was observed.In the electrical resistivity observation at constant temperatures at which methane pressure had increased, sharp peaks were monitored. The starting point of the rise in electrical resistivity was assigned to the starting point of hydrate formation, and a hydrate formation-pressure curve was obtained. In the observation of temperature and pressure in a closed system, a rapid drop in pressure and a rapid rise in temperature due to the methane hydrate formation were observed after a certain induction period. The starting points of the observations are on the curve obtained from the electrical resistivity measurements. The methane consumption rate, that is, the methane hydrate formation rate was higher at lower temperatures and at higher levels of super-cooling. These relationships are the same as those of the studies made by autoclave experiments. The methane hydrate in porous media, without stirring, was formed inhomogeneously. Reformation began in the whole media at the same time, after a short induction period because of the memory effects.