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This article investigates the flowing characteristics of the dissociated gas and water from hydrate in porous rock by utilizing the experimental model setup in this study. The apparatus has been validated by comparing the experimentally resulted equilibrium conditions of hydrate against the previously published results. This comparison shows excellent matches. With the developed apparatus, the experiments have been run for the depressurization method as well as the methanol injection method. From the analysis of the measured data of pressure, temperature, and resistance it was found that production and pressure behaviors are quite different from those of conventional gas reservoirs.

This study presents a numerical model for simultaneous flow of gas, water including methanol, and hydrate through methane hydrate reservoirs. The model has been developed to specially investigate the production behavior during injection of methanol with the combination of a depressurization mechanism. The model evaluates the local gas dissociation rate with methanol concentration using the kinetic theory proposed by Kim-Bishinoi and thermodynamics. This kinetic dissociation rate is computed with the aid of the empirical dissociation rate as a function of specific surface area and pressure difference. A number of simulations have been conducted to examine the effect of parameters related to methanol injection on the production behaviors of gas and water, that is, injection rate, time of injection, and methanol content. From the results of numerical studies, it is noted that the effect of methanol injection only appears near the well, rather than whole reservoir, since hydrate reservoirs are extremely low i...

Natural gas hydrates are known to occur in vast quantities at the ocean floor or in permafrost regions. In-situ hydrate contains great volumes of methane gas, which indicates a potential future energy resource. In this study, we have developed a three-dimensional, multi-phase (gas, water, and hydrate) flow finite-difference model by using implicit pressure explicit saturation technique in order to investigate simultaneous flow through ice-liked hydrate reservoir. The developed model is based on the depressurizing method as producing mechanism. The model evaluates local gas generation dissociated from the hydrate with the aid of kinetic dissociation theory proposed by Kim-Bishnoi. The computation of kinetic dissociation uses the empirical dissociation rate as a function of specific surface area between phases and pressure difference. With the developed model, a one-dimensional system has been simulated for analyzing the production performance of a hydrate reservoir and for investigating the effect of hydrate saturation on absolute permeability and relative permeability characteristics. Also, for the three-dimensional field-scaled reservoir system, a number of numerical exercises have been conducted to understand the effect of mass transfer and to characterize the flowing mechanism under the conditions of increased permeability resulting from the dissociation hydrate.

The analysis of hydrate equilibrium condition plays an important role to study pipeline blockage and production procedure of natural gas from in-situ hydrate reservoir. In this study, the experimental study has been performed to investigate hydrate dissociating and forming phenomena and we found out the methane hydrate equilibrium conditions. Also, a thermodynamic numerical model based on the statistical thermodynamics of van der Waals and Platteeuw has been developed for predicting the equilibrium condition of hydrate. This model implements an algorithm developed by Parrish and Prausnitz's method and it evaluates electrostatic interaction between ions in electrolyte solutions using the Debey-Huckel equation. Numerical studies using the model have been conducted for investigating the hydrate forming conditions of binary hydrocarbon mixtures such as methane-ethane, methane-propane, and methane-isobutane. Also, the effects of chemical inhibitors and electrolyte solutions on the hydrate equilibrium ...