Publication: Attenuation of specular and diffracted 2D multiples in image space
Full text at PDC
Advisors (or tutors)
Soc Exploration Geophysicists
In complex areas, the attenuation of specular and diffracted multiples in image space is an attractive alternative to surface-related multiple elimination (SRME) and to data space Radon filtering. We present the equations that map, via wave-equation migration, 2D diffracted and specular water-bottom multiples from data space to image space. We show the equations for both subsurface-offset-domain common-image-gathers (SODCIGs) and angle-domain common-image-gathers (ADCIGs). We demonstrate that when migrated with sediment velocities, the over-migrated multiples map to predictable regions in both SODCIGs and ADCIGs. Specular multiples focus similarly to primaries, whereas diffracted multiples do not. In particular, the apex of the residual moveout curve of diffracted multiples in ADCIGs is not located at the zero aperture angle. We use our equation of the residual moveout of the multiples in ADCIGs to design an apex-shifted Radon transform that maps the 2D ADCIGs into a 3D model space cube whose dimensions are depth, curvature, and apex-shift distance. Well-corrected primaries map to or near the zero-curvature plane and specularly reflected multiples map to or near the zero apex-shift plane. Diffracted multiples map elsewhere in the cube according to their curvature and apex-shift distance. Thus, specularly reflected as well as diffracted multiples can be attenuated simultaneously. We show the application of our apex-shifted Radon transform to a 2D seismic line from the Gulf of Mexico. Diffracted multiples originate at the edges of the salt body and we show that we can successfully attenuate them, along with the specular multiples, in the image Radon domain.
©2007 Society of Exploration Geophysicists. We thank WesternGeco for providing the data set, the sponsors of the Stanford Exploration Project for their support to carry out this study, and the associate editor and the anonymous reviewers for many helpful suggestions.
Alvarez, G., 2005, Mapping of water-bottom and diffracted 2D multiple reflections to image space: Stanford Exploration Project, SEP-123, 129–154. Alvarez, G., B. Biondi, and A. Guitton, 2004, Attenuation of diffracted multiples in angle-domain common-image gathers: 74th Annual International Meeting, SEG, ExpandedAbstracts, 1301–1304. Biondi, B., 2006, 3D seismic imaging: SEG. Biondi, B., and W. Symes, 2004, Angle-domain common-image gathers for migration velocity analysis by wavefield-continuation imaging: Geophysics, 69, 1283–1298. Biondi, B., and T. Tisserant, 2004, 3D angle-domain common-image gathers for migration velocity analysis: Geophysical Prospecting, 62, 575–591. Foster, D., and C. Mosher, 1992, Suppression of multiple reflections using the radon transform: Geophysics, 57, 386–395. Guitton, A., and W. Symes, 2003, Robust inversion of seismic data using the huber norm: Geophysics, 68, 1310–1319. Hampson, D., 1986, Inverse velocity stacking for multiple elimination: Canadian Journal of Exploration Geophysicists, 22, 44–55. Hargreaves, N., B. VerWest, R.Wombell, and D. Trad, 2003, Multiple attenuation using an apex-shifted Radon transform: 74th Annual International Meeting, SEG, ExpandedAbstracts, 1929–1932. Nekut, A., 1998, 3D surface-related multiple elimination: 68th Annual International Meeting, SEG, ExpandedAbstracts, 1511–1514. Rosales, D., and R. Biondi, 2005, Converted-waves angle-domain commonimage gathers: 75th Annual International Meeting, SEG, Expanded Abstracts, 959–962. Sacchi, M., and T. Ulrych, 1995, High-resolution velocity gathers and offset space reconstruction: Geophysics, 60, 1169–1177. ——–, 1996, Estimation of the discrete fourier transform as a linear inversion approach: Geophysics, 61, 4, 1128–1136. Sava, P., and S. Fomel, 2003, Angle-domain common-image gathers by wavefield continuation methods: Geophysics, 68, 1065–1074. Sava, P., and A. Guitton, 2003, Multiple attenuation in the image space: 73rd Annual International Meeting, SEG, ExpandedAbstracts, 1933–1936. ——–, 2005, Multiple attenuation in the image space: Geophysics, 70, no. 1, V10–V20. Trad, D., 2002, Interpolation with migration operators: 72ndAnnual International Meeting, SEG, ExpandedAbstracts, 2174–2177. van Dedem, E., and D. Verschuur, 1998, 3D surface-related multiple elimination and interpolation: 68th Annual International Meeting, SEG, ExpandedAbstracts, 1321–1324. ——–, 2002, 3D surface-related multiple prediction using sparse inversion: 71stAnnual International Meeting, SEG, ExpandedAbstracts, 1285– 1288. Verschuur, D., A. Berkhout, and C. Wapenaar, 1992, Adaptive surface-related multiple elimination: Geophysics, 57, 1166–1167