Elastic wave-mode separation for TTI media |

Figure 13(a) presents one snapshot of the simulated elastic wavefields using the anisotropic model shown in Figure 12. Figures 13(b), fig:vA-wom, and fig:pA-wom demonstrate the separation using conventional divergence and curl operators, VTI filters, and correct TTI filters, respectively. The VTI filters are constructed assuming zero tilt throughout the model, and the TTI filters are constructed with the dips used for modeling. As expected, the conventional divergence and curl operators fail at locations where anisotropy is strong. For example, in Figure 13(b) at coordinates km and km strong S-wave residual exists, and at coordinates km and km strong P-wave residual exists. VTI separators fail at locations where the dip is large. For example, in Figures 13(c) at coordinates km and km, strong S-wave residual exist. However, even for this complicated model, separation using TTI separators is effective at locations where medium parameters change rapidly.

vp,vs,rx,epsilon,delta,nu
Anisotropic elastic Marmousi II model with (a)
, (b)
,
(c) density, (d)
, (e)
, and (f) local tilt
angle
.
Figure 12. |
---|

uA-wom,iA-wom,vA-wom,pA-wom
(a) A snapshot of the vertical and horizontal displacement wavefield
simulated for model shown
in Figure 12. Panels (b) to (c) are
the P- and SV-wave separation using
and
, VTI
separators and TTI separators, respectively. The separation is
incomplete in panels (b) and (c) where the model is strongly
anisotropic and where the model tilt is large, respectively. Panel (d)
shows the best separation among all.
Figure 13. |
---|

Elastic wave-mode separation for TTI media |

2013-08-29