A New Method for Enhanced Production of Gas Hydrates with Carbon Dioxide

B. Peter McGrail, Environmental Technology Directorate, Pacific Northwest National Laboratory, PO Box 999, MS K6-81, Richland, WA 99352, phone: 509-376-9193, fax: 509-376-2210, pete.mcgrail@pnl.gov, H. Todd Schaef, Environmental Technology Directorate, Pacific Northwest National Laboratory, PO Box 999 MS K6-81, Richland, WA 99352, Mark D. White, Hydrology, Pacific Northwest National Laboratory, P.O. Box 999, MS K9-36, Richland, WA 99352, Tao Zhu, Petroleum Engineering, University of Alaska, 411 Duckering Building, Fairbanks, AK 99775, and Robert B. Hunter, ASRC Energy Services, 3900 C St., Suite 702, Anchorage, AK 99503.

Presently, depressurization, thermal stimulation, inhibitor injection, or a combination of these methods have been considered as possible means of gas hydrate production. A new method for enhanced gas hydrate recovery (EGHR) is described in this paper that takes advantage of the physical and thermodynamic properties of mixtures in the H₂O-CO₂ system combined with controlled multiphase flow, heat, and mass transport processes in hydrate-bearing porous media. The key steps in the process have been validated in laboratory-scale experiments. The method is attractive from a climate change perspective in that injected CO₂ is permanently sequestered as a solid gas hydrate as part of the production process. Additionally, refilling pore space with CO₂ hydrate is expected to maintain the mechanical stability of gas producing sediments, thus enhancing safety during gas production from both terrestrial and marine environments.

Gas Hydrates I
2005 AAPG Annual Convention (June 19-22, 2005) Technical Program