Multiple attenuation in the image space Paul Sava & Antoine Guitton Stanford University SEP

Goal Method feasible in 3-D Less expensive Dense data requirement Exploit the data/imaging mismatch Data: two-way propagation Migration: one-way extrapolation

Key technology Migration by wavefield extrapolation (WEM) Angle-domain common-image gathers High resolution Radon Transforms

The big picture WE prediction S/N separation Data RT & Mute Image Data NMO RT & Mute WE migration & ADCIG Image

Multiple attenuation by RTs –Moveout analysis NMO –Moveout analysis WE migration –S/N separation RT + Mute –S/N separation RT + Mute

3-D depth imaging WE migration –Multi-arrival Angle-gathers –Single-valued Kirchhoff migration –Single-arrival Offset-gathers –Multi-valued Biondi et al. (2003) Stolk & Symes (2002)   z x y

Synthetic example: data vs. image CMP CIG

Which Radon transform? Generic Radon Transform Parabolic Biondi & Symes (2003) Tangent q g(  )  z

Synthetic example: RTs Tangent Parabolic

Synthetic example: S/N separation primaries & multiples primariesmultiplesART + muteART

BP synthetic example

primaries & multiples primariesmultiplesART BP synthetic example

primaries & multiples primariesmultiples BP synthetic example: stacks

GOM example

primaries & multiples primariesmultiplesART + muteART GOM example: CIG 1

GOM example

primaries & multiples primariesmultiplesART + muteART GOM example: CIG 2

GOM example

GOM example: zoom 1 primaries & multiples

GOM example: zoom 1 primaries

GOM example: zoom 1 primaries & multiples

GOM example: zoom 1 multiples

GOM example

GOM example: zoom 2 primaries & multiples

GOM example: zoom 2 primaries

GOM example: zoom 2 primaries & multiples

GOM example: zoom 2 multiples

RT comparison Image space RTData space RT

Discussion PROs –Cheap & robust –3-D –Simple primaries –Migration artifacts CONs –Velocity model? –Moveout function? –Interactive mute –Inner angles –RT artifacts

Summary WE prediction S/N separation Data RT & Mute Image Data NMO RT & Mute WE migration & ADCIG Image

Summary Multiple attenuation after migration WE migration Angle gathers Cost/accuracy Complex propagation Cheap separation RT limitations filtering approach