Subsurface Decarbonization Options as CO2 Hydrates with Clean Methane Energy Recovery from Natural Gas Hydrate Reservoirs

Fundamentals of natural gas hydrates in porous media are first introduced with respect to the background, worldwide occurrences all around the world in different geological settings under varying pressure and temperature conditions in permafrost and continental hydrate reservoirs. This book chapter further elaborates the methods of exploiting the methane hydrate reservoirs. In order to complement and achieve the net-zero emission targets, the decarbonization options of subsurface CO2 sequestration in the form of gas hydrates are discussed with the help of depth versus hydrothermal and geothermal gradient, and CO2 hydrate phase diagram to depict the thickness of hydrate stability zone. Method of clean energy recovery in the form of methane coupled with the CO2 sequestration and storage has been reviewed with macroscale and microscale experiments in bulk and porous medium, followed by the visual glass micromodel results demonstrating the CO2 storage as gas hydrates, CO2 replacing methane in hydrates and the maintenance of sediment stability.