<p>Gas hydrates are potential energy resources which can be formed at low temperature and high pressure. The number of recoverable gas hydrates are limited due to the specific temperature, pressure conditions and technical limitations of gas production. Various production methods have been studied around the world to overcome these technical limitations. Gas production methods from gas hydrates are divided into methods of dissociating gas hydrates and non-dissociating gas hydrates. The dissociation methods including depressurization method, thermal injection method, and chemical inhibitor injection method can decrease in effective stress of the ground due to phase conversion. On the other hand, CH<sub>4</sub>-CO<sub>2 </sub>replacement method is geomechanically stable because it does not dissociate gas hydrates. Also, CH<sub>4</sub>-CO<sub>2 </sub>replacement method has the advantage of sequestering carbon dioxide while producing methane. However, CH<sub>4</sub>-CO<sub>2</sub> replacement method has the disadvantage such as low production efficiency and understanding kinetics of gas production. In this study, soaking, gas permeability of gas hydrate layer and hydrate saturation are considered in order to promote the production efficiency of CH<sub>4</sub>-CO<sub>2</sub> replacement method. Results show that production efficiency increases with the number of soaking process, the higher gas permeability and hydrate saturation. According to the experimental results in this study, the production efficiency can be increased by considering the soaking time, procedure and selecting the proper gas hydrates site.</p><p>Acknowledgement</p><p>This work is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 20CTAP-C152100-02). Also, it is supported by partial funding from NPRP grant # NPRP8-594-2-244 from the Qatar national research fund (a member of Qatar Foundation) and&#160; the Ministry of Trade, Industry, and Energy (MOTIE) through the Project &#8220;Gas Hydrate Exploration and Production Study (20-1143)&#8221; under the management of the Gas Hydrate Research and Development Organization (GHDO) of Korea and the Korea Institute of Geoscience and Mineral Resources (KIGAM).</p>
