Methane Recovery from Gas Hydrates by Injection of Supercritical CO2.

Kossel, Elke , Deusner, Christian, Bigalke, Nikolaus and Haeckel, Matthias (2012) Methane Recovery from Gas Hydrates by Injection of Supercritical CO2. [Poster] In: Fiery Ice from the Seas: 8. International Workshop on Methane Hydrate Research & Development. , 28.05.-1.6.2012, Sapporo, Japan .

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Abstract

The recovery of natural gas from CH4-hydrate deposits in sub-marine and sub-permafrost environments through injection of CO2 is considered a suitable strategy towards CO2-neutral energy production: CO2 activates the release of CH4 from the gas hydrate and is retained in the reservoir as immobile CO2-hydrate. In our experiments we could show that the injection of hot, supercritical CO2 is particularly promising. The addition of heat dissociates the CH4 hydrate and leads to a fast and continuous release of the encaged methane. However, the total production yield depends strongly on the structural properties of the surrounding hydrate/sand matrix. Additional CH4 can be liberated if percolating cooled, liquid CO2 gets in contact with CH4-hydrate triggering a direct exchange of the guest molecule. Furthermore, the transport of CH4 to a production well requires sufficient permeability of the sediment matrix and is hindered by the reformation of gas hydrates during the process. We present experimental data from a high-pressure flow-through reactor at different sediment temperatures (2 ?C, 8 ?C, 10 ?C) and hydrostatic pressures (8 MPa, 13 MPa). The efficiency of both CH4 production and CO2 retention was evaluated and best results were achieved at 8 ?C, 13 MPa. This behavior can be explained by the different percolation properties of the mobile phases at the various sediment temperatures. To substantiate these findings, we performed magnetic resonance imaging experiments that provided spatially resolved information on the fate of liquid CO2 in the sand/CH4-hydrate matrix. The results confirm the good accessibility of the pore space for liquid CO2 at 8 ?C, 13 MPa.

Document Type: Conference or Workshop Item (Poster)
Keywords: CO2 injection, hydrate conversion, CH4 extraction, hydrate-bearing sediments, gas hydrates, energy, methane, SUGAR project
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Projects: SUGAR
Date Deposited: 13 Jun 2012 08:02
Last Modified: 13 Jun 2012 08:02
URI: http://oceanrep.geomar.de/id/eprint/14411

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