310 likes | 428 Vues
This paper discusses methods for multiple attenuation in image space, focusing on the feasibility of applying wavefield extrapolation migration (WEM) in 3D scenarios. It highlights the advantages of dense data requirements and cost-effective solutions while addressing data and imaging mismatches. The research employs high-resolution Radon transforms to improve signal-to-noise separation and migration accuracy. Several synthetic examples illustrate the application of multiple attenuation techniques, demonstrating their potential for enhancing subsurface imaging quality in geophysical data.
E N D
Multiple attenuation in the image space Paul Sava & Antoine Guitton Stanford University SEP paul@sep.stanford.edu
Goal • Method feasible in 3-D • Less expensive • Dense data requirement • Exploit the data/imaging mismatch • Data: two-way propagation • Migration: one-way extrapolation paul@sep.stanford.edu
Key technology • Migration by wavefield extrapolation (WEM) • Angle-domain common-image gathers • High resolution Radon Transforms paul@sep.stanford.edu
The big picture Image Image RT & Mute S/N separation WE migration & ADCIG RT & Mute S/N separation NMO WE prediction Data Data paul@sep.stanford.edu
Multiple attenuation by RTs Moveout analysis NMO Moveout analysis WE migration • S/N separation • RT + Mute • S/N separation • RT + Mute paul@sep.stanford.edu
3-D depth imaging WE migration Multi-arrival Angle-gathers Single-valued Kirchhoff migration Single-arrival Offset-gathers Multi-valued y x g z g Biondi et al. (2003) Stolk & Symes (2002) paul@sep.stanford.edu
Synthetic example: data vs. image CIG CMP paul@sep.stanford.edu
Which Radon transform? g q g(g) z Generic Radon Transform Parabolic Tangent Biondi & Symes (2003) paul@sep.stanford.edu
Synthetic example: RTs Parabolic Tangent paul@sep.stanford.edu
Synthetic example: S/N separation primaries & multiples ART ART + mute multiples primaries paul@sep.stanford.edu
BP synthetic example paul@sep.stanford.edu
BP synthetic example primaries & multiples ART multiples primaries paul@sep.stanford.edu
BP synthetic example: stacks primaries & multiples multiples primaries paul@sep.stanford.edu
GOM example paul@sep.stanford.edu
GOM example: CIG 1 primaries & multiples ART ART + mute multiples primaries paul@sep.stanford.edu
GOM example paul@sep.stanford.edu
GOM example: CIG 2 primaries & multiples ART ART + mute multiples primaries paul@sep.stanford.edu
GOM example paul@sep.stanford.edu
GOM example: zoom 1 primaries & multiples paul@sep.stanford.edu
GOM example: zoom 1 primaries paul@sep.stanford.edu
GOM example: zoom 1 primaries & multiples paul@sep.stanford.edu
GOM example: zoom 1 multiples paul@sep.stanford.edu
GOM example paul@sep.stanford.edu
GOM example: zoom 2 primaries & multiples paul@sep.stanford.edu
GOM example: zoom 2 primaries paul@sep.stanford.edu
GOM example: zoom 2 primaries & multiples paul@sep.stanford.edu
GOM example: zoom 2 multiples paul@sep.stanford.edu
RT comparison Image space RT Data space RT paul@sep.stanford.edu
Discussion PROs Cheap & robust 3-D Simple primaries Migration artifacts CONs Velocity model? Moveout function? Interactive mute Inner angles RT artifacts paul@sep.stanford.edu
Summary Image Image RT & Mute S/N separation WE migration & ADCIG RT & Mute S/N separation NMO WE prediction Data Data paul@sep.stanford.edu
Summary • Multiple attenuation after migration • WE migration • Angle gathers • Cost/accuracy • Complex propagation • Cheap separation • RT limitations • filtering approach paul@sep.stanford.edu