HR: 0800h
AN: MR41A-0911    [Abstracts]
TI: Detecting the Change in Physical Properties of Methane Hydrate Matrix with the Freezing and Thawing Process
AU: * Onishi, K
EM: gp@leeda.com
AF: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501 Japan
AU: Tsukada, K
EM: tsukada@kumst.kyoto-u.ac.jp
AF: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501 Japan
AU: Matsuoka, T
EM: matsuoka@kumst.kyoto-u.ac.jp
AF: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501 Japan
AU: O_fNeill, A
EM: adam@earth.kumst.kyoto-u.ac.jp
AF: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501 Japan
AU: Yamada, Y
EM: yama@electra.kumst.kyoto-u.ac.jp
AF: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501 Japan
AB: This is the experimental study detecting the change in physical properties of reservoir rocks when pore-filling methane hydrate crystal is repeatedly produced and dissolved. The stability region of the methane hydrate, which is influenced by the fluctuation of sea level or fault activity, rises and falls many times over a long period. Therefore, it is considered that the freezing and thawing are continuously and rhythmically processed around the depth of the BSR. We surmise that the rock framework is destructed by the freezing and thawing process. This process forms fracture zones in the hydrate reservoir and the mudstone layer, which seals the formation water. Hence, this hypothesis suggests temporal changes in the rock condition around the BSR. We performed the hydrate production and destruction in a pressure vessel for demonstrating the rock breaking with the freezing and thawing process. The elastic wave velocity was measured as an indication of the state of destruction of the framework. From these results, we propose a reservoir model in the methane hydrate layer under the sea, for the production of methane gas.
DE: 3004 Gas and hydrate systems
DE: 5102 Acoustic properties
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005