Extraction of methane hydrate energy by carbon dioxide injection-key challenges and a paradigm shift

Significant effort including field work has been devoted to develop a natural gas extraction technology from natural gas hydrate reservoirs through the injection of carbon dioxide. Natural gas hydrate is practically methane hydrate. The hypothesis is that carbon dioxide will be stored as hydrate owing to its favorable stability conditions compared to methane hydrate. Although the dynamics of the CO2/CH4 exchange process are not entirely understood it is established that the exchange process is feasible. The extent is limited but even if the CH4 recovery is optimized there is a need for a CH4/CO2 separation plant to enable a complete cyclic sequence of CO2 capture, injection and CH4 recovery. In this paper we propose an alternative paradigm to the Inject (CO2)/Exchange with (CH4)/Recover (CH4) one namely Recover (CH4) first and then Inject (CO2) for Storage. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.