Formation kinetics of CO₂ gas hydrates in sandy sediment and change in permeability during crystal growth: Carbon capture and storage system using gas hydrates

The method of CO2 sequestration using gas hydrates has the advantages that (1) the CO2 is stored as a solid which reduces the risk for leakage; (2) a geological containment structure is not required; (3) it could be suitable for direct flue gas injection since the nitrogen in the flue gas would not be trapped; (4) if injected into a methane gas hydrate reservoir it could simultaneously produce methane while trapping the CO2 as a hydrate (through molecular exchange). The main goals of this research are to elucidate the fundamentals underlying crystal growth and to measure the formation kinetics of CO2 gas hydrates in sandy sediments. Experiments on formation kinetics and crystal growth were carried out using a high-pressure vessel and a Raman spectrometer. A bulk-scale experiment was also conducted to observe the behavior of CO2 hydrate formation in sandy sediments. The change in permeability and porosity in porous media was measured in the process of crystal growth.