Recovering CH_4 from natural gas hydrate with CO_2 in porous media below the freezing point

摘要

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 CO_2-CH_4 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 CO_2 gas. And the replacement rate and efficiency reached up to 0.403 mmol/h and 13.20% during the experiment. Furthermore, the results also showed that the replacement rate of CO_2-CH_4 hydrate was slower below the freezing point.