I have just gotten my first filtered seismic image using prediction error filters (PEFs), so I thought I should share this experience with our Acceleware blog readers. Coming from electromagnetic field modeling, I have quite a bit of experience with wave propagation through different types of materials. However, image filtering is a whole new (and interesting) world to me.

As most of the people doing seismic imaging know, reverse time migration (RTM) images obtained using a simple cross-correlation condition contain low frequency artifacts created by the unwanted cross-correlation of head waves and backscattered waves. These artifacts are clearly visible as the dark areas near the top of the BP model example shown in figure below.

Many different techniques of attenuating the RTM artifacts are presented in the literature. In this project, I have tried to clear the final image using PEFs. Since PEFs are applied to the stacked image, as the last step in the migration process, this method is relatively cheap. The noise in the water area is used to determine the PEF coefficients. The obtained filtered image is shown in figure below. The low frequency artifacts are mostly attenuated, although some noise still persists. Of course, a better attenuation can be obtained by using a more sophisticated noise model and/or least-square filtering.

While the PEF work is still ongoing and looks very promising, it still has a way to go before superseding our current best post-processing methods, as shown below.

Written by guest blogger and Acceleware Research Scientist Damir Pasalic.

Comments:

Seems like a nice improvement, keep up the progress!
# Posted By david | 1/13/10 4:03 AM