Curved-ray replacement dynamics for 3-D marine data

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:542957

Schneider, Jr, W A

The sea floor in most marine 3-D survey areas exhibits only gentle variations, such as a small, basinward dip, thus conventional seismic data processing, where several of the key processing steps assume reflections are hyperbolic, is not hampered by the sea floor geology (unless shallow gas occurs). Australia`s Gippsland basin, however, typifies the few basins where the sea floor exhibits large variations. In the Gippsland case the cause is channeling. The sea floor`s shape causes nonhyperbolic distortion in the data that makes these key processing steps perform poorly. {open_quotes}Replacement-velocity{close_quotes} techniques attempt to remove these distortions prestack, so that the conventional processing will perform better. Few approaches, however, are designed for 3-D data. A new method, based upon a 3-D ray-bending algorithm performs efficient, approximate 3-D velocity replacement. The algorithm requires a gridded and smoothed bathymetry map, and a V(z) interval-velocity function that represents the sediments. It consumes only a few percent of a typical 3-D survey`s processing budget, and it has been successfully used to process 3-D data from the Gippsland basin. Since the method reduces nonhyperbolic moveout in the prestack data, it also makes the time-consuming 3-D velocity analysis steps easier to perform.

• OSTI ID: 542957
• Report Number(s): CONF-951013--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
AUSTRALIA
DATA ANALYSIS
EXPLORATION
PETROLEUM DEPOSITS
SEDIMENTARY BASINS
SEISMIC SURVEYS