Submarine gas hydrate reservoir simulations - a gas/liquid fluid flow model for gas hydrate containing sediments

In the medium term, gas hydrate reservoirs in the subsea sediment are intended as deposits for CO2 from fossil fuel consumption. This idea is supported by the thermodynamics of CO2 and methane hydrates and the fact, that CO2 hydrates are more stable than methane hydrates in a certain PT range. The potential of producing methane by depressurization and/or by injecting CO2 is numerically studied in the frame of the research project SUGAR. Here, a numerical model for the production of natural gas from submarine gas hydrate reservoirs based on a 2-phase Darcy flow in a sediment/hydrate matrix is described. The model was implemented in COMSOL with BDF time stepping and a fully coupled solution approach. Simulation cases presented and discussed here are the depressurization of a methane hydrate bearing reservoir at varied layer disposals and a depressurization with simultaneous injection of CO2 by a second injection well.