Comprehensive literature review on CH4-CO2 replacement in microscale porous media

Gas production studies from natural gas hydrate reservoirs have been the subject of extensive research in recent years. Although CH4-CO2 replacement production method from gas hydrates has many advantages, the number of the studies related to this production method are less than depressurization production method studies, especially in microscale porous media. Hence, this paper presents a comprehensive literature review on CH4-CO2 replacement to better understand the associated processes and mechanisms in microscale porous media with emphasis on micromodel experiments, 3D imaging, other visualization testing method and pore network modelling. Moreover, the advantages and disadvantages of currently available CH4-CO2 replacement studies were investigated. The critical issues of the replacement method were underlined and new suggestions have been offered for future investigations.