HR: 08:15h
AN: S51A-01    [PDF]
TI: Beamlet Imaging and Local Inversion for Complex Structures
AU: * Wu, R
EM: wrs@es.ucsc.edu
AF: Modeling and Imaging Lab, IGPP/Earth Sciences, Univeristy of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95060 United States
AU: Luo, M
EM: mqluo@es.ucsc.edu
AF: Modeling and Imaging Lab, IGPP/Earth Sciences, Univeristy of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95060 United States
AU: Chen, L
AF: Institue of Geophysics, Chinese Academy of Sciences, Beijing China, P.O.Box 9701, Beijing, 100101 China
AB: Beamlet decomposition of wavefields is defined as wavelet transform applied to wavefield along spatial axes. Beamlets has both spatial and directional localization satisfying the Heisenberg uncertainty principle. We have used both Gabor-Daubechies frame and local-cosine basis for the decomposition. The theory of local perturbations and wave propagators in beamlet domain has been developed. In this presentation we will summarize the theory and method of beamlet propagation and imaging, and show the 2D and 3D imaging (prestack depth migration) results for SEG/EAGE salt models. The high-resolution and high quality images demonstrate the excellent performance and wide-angle capacity of beamlet imaging. Based on beamlet imaging in angle-domain, a method of local AVA (amplitude versus angle) and local inversion is proposed to estimate the medium parameters near a local discontinuity (reflector). The local image matrices derived during the amplitude-preserving imaging process can be reduced to common refection-angle image (CRAI) gathers and common dip-angle image (CDAI) gathers. CDAI gathers can be used to determine the dip-angle of the reflector and CRAI gathers are then used for local AVA analysis. In the target area, local inversion can be conducted based on local AVA and velocity analyses. Preliminary numerical tests of local AVA analysis will be shown to demonstrate the feasibility of the approach.
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting