Seismic modeling is a technique for simulating wave propagation through the
subsurface. For a given geological model, seismic modeling allows us to generate
snapshots of wave propagation and synthetic data. In my dissertation, for real seismic
events I have chosen to implement the finite-difference modeling technique. When
adequate discretization in space and time is possible, the finite-difference technique is
by far one of the most accurate tools for simulating elastic-wave propagation through
complex geological models.
In recent years, a significant amount of work has been done in our group using
2D finite-difference modeling. For complex salt structures which exploration and pro-
duction industries meet today, 2D finite-difference modeling is not sufficient to study
subsalt imaging or the demultiple of subsalt models. That is why I have developed a
3D finite-difference modeling code.
One of the key challenges that I have met in developing the 3D finite-difference
code is to adapt the absorbing boundary conditions. Absorbing boundary conditions
are needed to describe the infinite geological models by limited computing domain.
I have validated the 3D finite-difference code by comparing its results with analytic
solutions. I have used 3D finite-difference program to generate data corresponding
to 3D complex model which describes salt and subsalt structures of Gulf of Mexico.
The resulting data include reflections, diffractions and other scattering phenomena.
I have also used finite-difference program in anisotropic context to show that we can effectively predict shear-wave splitting and triplication in the data.
There are new sets of events that are not directly recorded in seismic data, they
have been called virtual events. These events are turning to be as important as real
events in modern data processing. Therefore we also have to learn how to model them.
Unfortunately, they cannot yet be modeled directly from finite-difference. Here I will
describe how to model these events by using cross correlation type representation
theorem. As illustration of how important of virtual events for seismic data process-
ing, I also described an internal multiple attenuation technique which utilized virtual
events.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2974 |
| Date | 15 May 2009 |
| Creators | Yang, Xiujun |
| Contributors | Ikelle, Luc |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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