Sequestration of CO₂ in geologic formations is a technologically and financially viable option for controlling CO₂ concentration in ambient atmosphere. Present proposal involves sequestration of CO₂ in marine hydrate reservoirs, which are the repositories of naturally formed CH₄-hydrates. While CH₄-hydrate constitutes the largest resource for CH₄ fuel, recovery of CH₄ from the marine hydrate reservoir seems to be quite challenging. Injection of CO₂ in the CH₄-hydrate reservoir enhances CH₄ recovery via formation of CO₂- hydrate. Sequestration of CO₂ in its hydrate form ensures safe and long-term storage of CO₂ in large amount. Finally, the sequestration of CO₂-hydrate in marine hydrate reservoir helps to maintain the structural integrity of the fragile marine ecosystem.  The proposed research involves modeling of CO₂ sequestration in marine hydrate reservoir followed by the development of 3-D, transient, hydrate reservoir simulator. The model involves the nonlinear coupling of mass, momentum and energy transport with the kinetics of hydrate formation/dissociation as well as phase changes. The fundamental model comprises multiphase flow in an unsaturated porous media where the media properties vary in space and time. The kinetics of formation and disappearance of gas, liquid, and hydrate phases are adapted from experimental results available in the literature. The model includes the effects of water salinity, CO₂ solubility in liquid H₂O as well as the influence heat transfer and ice formation on the overall dynamics of the process. Simulations are proposed to be carried out for Indian conditions, predict the amount of CO₂ that can be disposed off in the marine environment and the consequent amount of methane produced from the reservoir.