A mathematical model was developed in this study for predicting the dynamic heat transfer from geothermal reservoirs to natural gas hydrate (NGH) reservoirs for reducing the cost of natural gas production from gas hydrate deposits. The derived analytical solution was validated by numerical simulation. The expression of the mathematical model shows that, for a given geothermal-gas-hydrate system, the heat transfer is proportional to the mass flow rate of heat-transferring work fluid. A field-case study with the mathematical model indicates that the NGH reservoir temperature should rise quickly at any heat-affected point, but it should propagate slowly in the radial direction. It may take more than two years to dissociate NGH within 20 m of the heat dissipator wellbore due to thermal stimulation. The slow process of heat conduction suggests that the heat dissipator wellbores should be perforated to cause heat convection into the gas hydrate reservoirs to expedite gas production from the gas hydrate reservoirs.
Keywords gas hydrate, geothermal energy, natural gas production, heat transfer, mathematical modeling