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

B. Peter McGrail¹, H. Todd Schaef¹, Mark D. White¹, Tao Zhu², and Robert B. Hunter^3
1 Pacific Northwest National Laboratory, Richland, WA
² University of Alaska, Fairbanks, AK
³ ASRC Energy Services, Anchorage, AK

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.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005