Recovering CH4 from natural gas hydrate with CO2 in porous media below the freezing point

The recovery of methane from gas hydrate layers that have been detected in permafrost regions is a promising perspective in the future. In order to study the replacement characteristics of CO2-CH4 hydrate in permafrost environments, simulation experiment was carried out in this work. The results indicated that the replacement rate and efficiency increased with the increasing of injection pressure of CO2 gas. And the replacement rate and efficiency reached up to 0.403mmol/h and 13.20% during the experiment. Furthermore, the results also showed that the replacement rate of CO2-CH4 hydrate was slower below the freezing point.