Experimental Study on the Thermodynamic Decomposition Characteristics of Methane Hydrate in Porous Media

The marine natural gas hydrates commercial exploitation has become a hot topic in recent years. Understanding the thermodynamic decomposition characteristics of methane hydrates in porous media is crucial for achieving commercial hydrate exploitation. The thermodynamic decomposition characteristics of methane hydrate under different hydrate saturation (18.3%, 16.8%, 24.6%, and 24.4) in porous media was studied. The result indicted that methane hydrate decomposition characteristic in the constant-volume decomposition process is influenced by the synergistic effects of pressure and temperature. In the constant-pressure decomposition process, the hydrate decomposition characteristic is affected by temperature. When there is ice in the reactor, the ice melting first controls the sediment temperature. There is a very small amount of hydrate decomposition, influenced by thermal fluctuations. When the ice melts, the change of methane hydrates phase controls the sediment temperature. The finding of this work on the thermodynamic decomposition characteristics of methane hydrates is significant to the commercial exploitation of marine natural gas hydrate reservoirs.