Study of methane replacement in hydrates by carbon dioxide in a cyclic process

The process of replacement of methane molecules in hydrate by carbon dioxide was studied by PVT measurements in a cyclic process. A cycle of the process consisted of the injection of some amount of carbon dioxide into the gas phase, which contacts with the hydrate, relaxation of the gas–hydrate system and evacuation of a portion of gas coexisting with the hydrate. The hydrate number and concentration of gas mixture in the hydrate were determined during the replacement process. The dependency of the extent of methane replacement on the amount of injected carbon dioxide was obtained.