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Seismic
Gathers and Its Impact on Deepwater Field Development
Paparoni, Guido1,
David Bartel2, Casey Simms3, Peter Mitchell3,
Henry Megan2 (1) ChevronTexaco
Overseas Petroleum Co, Houston, TX (2) ChevronTexaco Energy Technology Company
(3) CABGOC,
Traditional interpretation of seismic gathers is based on
arbitrary traverses that display stationary information over features such as
fluid changes. In Block 14, deepwater seismic gathers have been loaded
through a proprietary process into a 3-D visualization package, which allows
for a temporal component to be added to the interpretation.
The technique uses vertical planes that correspond to constant
offset seismic panes, which are panned in a crossline direction allowing for
dynamic near to far offset comparison of the data. The use of traditional
in-line gather displays, including arbitrary traverses, is also possible.
Furthermore, stacked-data seismic interpretation such as faults, horizons and
oil/water contacts, can also be loaded and compared with the dynamic response
of the seismic data as near to far offsets are panned.
We illustrate examples of how these techniques have been applied
by the operator (CABGOC, a ChevronTexaco affiliate) in association with other
members of the Block 14 Contractor Group (Sonangol P&P, ENI, Total and
GALP) to the deepwater Negage and Lobito fields in Block 14 Angola.
Applications of
this method include (1) validation of seismic
processing flows including moveout
corrections, (2) detection of multiple interference, (3) comparison of velocity
models over the predicted oil/water contact surfaces, (4) validation of the
high- or low-imped-ance nature of reservoirs, (5) identification of phase
changes resulting from Earth interaction as opposed to poor moveout, (6)
selection of features that should be mapped on a given stack (7) identification
of exploitation opportunities by extension of known hydrocarbon responses.