Estimation of Surface Area of Methane Hydrate in Sediments

摘要

Surface area of methane hydrate in sediments is necessary to predict the amount of dissociated methane gas. It depends on the morphology how methane hydrate exists in sediments under the ground. The purpose of this study is to obtain a model equation for the surface area of methane hydrate in sediments as a function of porosity, hydrate saturation, and size of sediment particles. We conducted hydrate dissociation experiment in a pressure cell filled by glass beads. It is expected that the temperature in the cell first goes down to the equilibrium point due to hydrate dissociation, and that the dissociation ceases until heat is transferred from the surrounding cell walls. We simulated this process by using a numerical model with tentative surface areas. The surface area is, then, estimated by comparing the amounts of dissociated gas in the experiments and in the numerical simulations.