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The routine use of 3D time seismic data since
the late 1980s has been instrumental in reducing
E&P risk around the world, but over an area
exhibiting complex velocity or geology, even
a well-defined 3D subsurface model in time is
not sufficient to accurately characterize the
geology. Such plays benefit from prestack depth
migration because the velocity model derived
during the process is inherently more accurate
than that for time processing. Using this velocity
model and prestack time seismic traces as input,
prestack depth migration enhances the imaging
or focusing of the resulting seismic data by
placing reflections in more accurate depth space.
As a result, the structure and trap volumetrics
are also more accurately revealed and positioned.
Both 2D and 3D prestack depth imaging are making
it possible to reduce the risk associated with
more complex plays, maximizing the opportunity
for successful discoveries and more economical
development. Such plays are found around the
world and commonly include those related to
salt, volcanics, thrust faults, fault shadows,
reefs, shallow gas and others where lateral
velocity variation is significant.
Modern depth imaging requires the ability to
build transversely isotropic models of the subsurface.
Vertical transverse isotropy (VTI) assumes that
the symmetry axis is vertical, whereas the more
general case of tilted transverse isotropy (TTI)
may have a symmetry axis away from vertical.
While VTI is a simpler representation, TTI may
be more geologically plausible for sedimentary
formations such as shales.
At Absolute Imaging Inc. we offer the following
Depth Imaging Services:
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Ray trace based modeling for both 2D
and 3D (Isotropic & Anisotropic)
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Model building using both wells and
seismically derived velocities with isotropic
and anisotropic (VTI & TTI) capabilities
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2D post and pre stack Kirchhoff Depth
Migration and tomography updates with isotropic
and anisotropic (VTI & TTI) capabilities
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3D post and pre stack Kirchhoff Depth
Migration and tomography updates with isotropic
and anisotropic (VTI & TTI) capabilities
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