HR: 0800h
AN: OS21C-1254    [Abstracts]
TI: Imaging the internal structure of a warm core ring in the Gulf of Mexico using industry high resolution seismic data
AU: * Seymour, J C
EM: joel@uwyo.edu
AF: University of Wyoming, Dept of Geology and Geophysics # 3006, Laramie, WY 82071-3006 United States
AU: Holbrook, W S
EM: steveh@uwyo.edu
AF: University of Wyoming, Dept of Geology and Geophysics # 3006, Laramie, WY 82071-3006 United States
AB: We investigate the water column sound speed during an industrial seismic survey from the Gulf of Mexico, imaging a warm core ring that passes through the survey during acquisition. We use single seismic reflection line donated by Schlumberger Ltd., from a 3D survey, to image water column reflections and estimate a sound speed field within the water column during the survey. WesternGeco Ltd. acquired a 65 km line in the Green Canyon area in August of 2001 using a group interval of 12.5m, 412 channels per streamer aboard the MV. Legend. The transect runs southwest from shallow to deeper water across a canyon area and intersects a warm core ring feature traveling eastwards through the survey area. We present a migration of the water column data to image the water masses within a warm core ring with a resolution of 6.25 m along the sail line and a 15 m vertical resolution. Images processed show strong seismic reflectors due to temperature variations within the water column. The stack section of the line shows a distinct dipping event in the reflectors as the line is acquired moving towards the center of the ring. A distinct fine structure is present in the reflectors at a depth of approx 750m at the edge of the ring rising to approx. 600m depth towards the center of the ring. The affect of the warm core ring seems to significantly perturb the sound speed profiles within the water column along the entire 64km line with the effects of the ring being concentrated in the 225m to 1000m depth range. Velocity analysis indicates a complex velocity profile highly spatial variant through the ring structure. This survey provides a detailed image of water sound speed changes due a highly localized feature within the water column from data acquired during an industry seismic survey.
DE: 0910 Data processing
DE: 0930 Oceanic structures
DE: 0935 Seismic methods (3025)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting