Numerical Study on Dissociation of Methane Hydrate and Gas Production Behavior in Laboratory-Scale Experiments for Depressurization: Part 3-Numerical Study on Estimation of Permeability in Methane Hydrate Reservoir

摘要

We conducted an experimental study on the dissociation of methane hydrate (MH) and gas production behavior by depressurization in sediments. To reproduce the actual flow condition of gas and water, disc-shaped samples of MH in sediments were used. Horizontal radial flow in porous media during MH dissociation was studied under a variety of vertical loads in order to reproduce field conditions in real MH sediments. From experimental observations, it was found that the MH dissociation consisted of 2 stages due to the latent heat of sediments and thermal conduction. Based on experimental results, we carried out numerical simulations of laboratory-scale experiments for depressurization. Thermal conductivity that dominated dissociation behavior was optimized. Further, we formulated realistic relative permeability curves that allowed us to reproduce the gas-water production behavior under the existence of MH.