next up previous [pdf]

Next: Interpretation Up: Results Previous: Ordovician


We use the Khuff synthetic model to illustrate how diffractions may be used to characterize features at the reservoir scale using higher frequency data.

zo-ovr k-diffractions
Figure 10.
Zero-offset Khuff data: (a) conventional; (b) diffraction
[pdf] [pdf] [png] [png] [scons]

zo-ovr-mig k-diffractions-mig
Figure 11.
Migrated Khuff images: (a) conventional; (b) diffraction
[pdf] [pdf] [png] [png] [scons]

zo-ovr-migI k-diffractions-migI aiI
Figure 12.
Khuff cross sections for 150 m crossline: (a) conventional image; (b) diffraction image; (c) acoustic impedance model
[pdf] [pdf] [pdf] [png] [png] [png] [scons]

zo-ovr-migX k-diffractions-migX aiX
Figure 13.
Khuff cross sections for 250 m inline: (a) conventional image; (b) diffraction image; (c) acoustic impedance model
[pdf] [pdf] [pdf] [png] [png] [png] [scons]

The experiment begins with the Khuff velocity and density models, shown in Figures 2a and 2b respectively. We multiply density and velocity data to obtain acoustic impedance (Figure 2c). Reflectivity is calculated from this acoustic impedance, transformed to the time domain, convolved with a 100 Hz ricker wavelet, and transformed back to the depth domain to provide an idealized seismic reflection image. We model the zero-offset reservoir response using one-way wave equation modeling in the frequency domain (Sava, 2007), and then upward continue the reservoir response through a 3 km thick overburden to generate the zero-offset data, shown in Figure 10a.

We separate diffractions using PWD. Data slopes are calculated and reflection events conforming to slope are removed, leaving zero-offset data with primarily diffractions (Figure 10b).

Conventional and diffraction zero-offset data are then downward continued through the smoothed-slowness overburden, and then depth migrated through the smoothed-slowness reservoir. This provides a conventional image (Figure 11a) and a diffraction image (Figure 11b). We zoom in on a horizontal cross section along crossline 150 m for the conventional and diffraction images as well as the acoustic impedance of the synthetic model, creating Figure 12. We also generate a cross section along inline 250 m (Figure 13).

next up previous [pdf]

Next: Interpretation Up: Results Previous: Ordovician