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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL STUDY OF THE EFFECT OF OVER/UNDERBURDEN PERMEABILITY ON METHANE HYDRATE DISSOCIATION BY DEPRESSURIZATION

Get access (open in a dialog) DOI: 10.1615/IHTC16.mpf.023460
pages 6463-6470

Resumo

Methane hydrate (MH) is found in larger amounts in the ocean sediments and permafrost regions, and is regarded as one of the potential and substantial energy resources. In general, the hydrate-bearing layer in nature is confined by overburden and underburden. This study is focused on the effect of overburden and underburden permeability on the process of methane hydrate dissociation. Simulation runs are conducted on a hypothetical MH deposit model by depressurization with a single vertical well. Three cases with different permeability in overburden and underburden, including permeable boundaries, semi-permeable boundaries and impermeable boundaries, are used to analyze the influence of heat and fluid transferred from the overburden and underburden on the evolution of temperature, pressure and saturation fields during gas production. The simulation results indicate that the overburden and underburden permeability has a significant effect on the temperature and pressure evolution of hydrate-bearing layer, and gas production during hydrate dissociation. The impermeable boundaries can limit the heat transfer between the hydrate-bearing layer and over/underburden, but intensify the propagation of pressure reduction in the hydrate-bearing layer. For the hydrate deposits with permeable boundaries, hydrate dissociation mainly occurs on the sharp front of dissociation, whereas with impermeable boundaries, hydrate dissociation can occur over a large volume of hydrate-bearing layer. Additionally, it is found that the hydrate deposits with impermeable boundaries have much better gas production performance.