Simulation of CO2 Storage into Methane Hydrate Reservoirs, Non-equilibrium Thermodynamic Approach

Abstract

CO2 in the atmosphere has been recognized as one of the main reasons of climate change. Capturing CO2 and storing it within CH4 hydrate reservoirs in the form of hydrate could serve triple purposes of CH4 production, compen-sation of CO2 sequestration expenses, as well as maintaining geomechanical stability of the CH4 producing area. Two mechanisms for this conversion from in situ CH4 hydrate to CO2 dominated hydrate have been proposed in the open literature. A solid state exchange mechanism is very slow compared to the other mechanism, in which heat released through formation of new CO2 hydrate is the primary cause for dissociation of the in situ CH4 hydrate. In this work we utilized a reactive transport simulator, RetrasoCodeBright, to examine the formation of new CO2 hydrate in realistic formations of CH4 hydrate filled sediments as a mechanism for CO2 / CH4 hydrate swapping. Results from the implementation show CO2 hydrate formation within the geological structure of natural gas hydrate.