HR: 0830h
AN: OS51C-0884    [PDF]
TI: Methane Hydrate Detection Using Dense Velocity Analysis
AU: * Hamajima, T
EM: hamajima@jgi.co.jp
AF: JGI Inc., 1-5-21, Otsuka, Bunkyo-ku, Tokyo, 112-0012 Japan
AU: Inamori, T
EM: ina@japex.co.jp
AF: Japan Petroleum Exploration, Co., Ltd, 1-2-1 Hamada, Mihama-ku, Chiba, 261-0025 Japan
AU: Hato, M
EM: mhato@japex.co.jp
AF: Japan Petroleum Exploration, Co., Ltd, 1-2-1 Hamada, Mihama-ku, Chiba, 261-0025 Japan
AU: Asakawa, E
EM: asakawa@jgi.co.jp
AF: JGI Inc., 1-5-21, Otsuka, Bunkyo-ku, Tokyo, 112-0012 Japan
AU: Oikawa, N
EM: oikawa-nj@jnoc.go.jp
AF: Japan National Oil Corporation, Technology Research Center, 1-2-2 Hamada, Mihama-ku, Chiba, 261-0025 Japan
AB: As one of approach to evaluating the total amount of methane hydrate, a method utilizing the results of velocity analysis on reflection seismic exploration data is studied. Well log sonic data reveals that the velocity of the methane hydrate bearing zone is greater than that of surrounding sediments. Thus, the velocity information can be used for detection of the methane hydrate zone.\\In order to delineate detailed velocity variations, a dense velocity analysis is performed using an automatic velocity picking tool. Because the target depth of this analysis is fairly shallow ( less than 400m below sea bottom ), a simple algorithm can be used for the picking.\\Dense velocity analysis is applied to 2D marine seismic data acquired over the Nankai Trough, Offshore Japan. Comparison between automatic and manual picking results showed a similar trend at the shallower zone above BSR. The processing time, however, is considerably different; it takes several days for manual picking against a few minutes for automatic picking.\\In the automatic picking process, the velocity trend is also estimated. The difference between actual velocity and velocity trend provides another viewpoint for the delineation of velocity anomaly zone.\\On going work includes an analysis of 3D marine seismic data in the Nankai Trough. Provisional results will be shown in this meeting.
DE: 0910 Data processing
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting