HR: 0830h
AN: S21B-17
TI: P-wave Moveout Analysis, Traveltime computation, and Prestack F-K Migration in Transversely Isotropic Media
AU: * Mukherjee, A
EM: anubrati@utig.ig.utexas.edu
AF: Institute for Geophysics, University of Texas at Austin, 4412 Spicewood Springs Rd, Bldg 600, Austin, TX 78759 United States
AU: Sen, M K
EM: mrinal@utig.ig.utexas.edu
AF: Institute for Geophysics, University of Texas at Austin, 4412 Spicewood Springs Rd, Bldg 600, Austin, TX 78759 United States

AB: Occurrences of anisotropy in the seismic data are widespread at all scales. Inclusions of these anisotropy effects become important for obtaining correct images and target depths. We have formulated an interactive reflection traveltime analysis procedure for P-waves in VTI media in the delay-time-slowness domain. Assumption of weak anisotropy enables us to use a two term representation of vertical slowness, which results in direct estimates of interval elliptic velocity and anisotropic parameter kappa. Conventional ray tracing methods are generally difficult to apply in the VTI media. At times, lack of information on vertical P wave velocity restricts us to use the time grided elliptic velocity and kappa as input for traveltime computation in offset-time domain. We have formulated travel time calculation scheme based on the Fermat's principle that can generate travel times rapidly either in offset-depth or offset-two way time domain. Unlike conventional methods, we use phase velocity alone and do not include head wave paths in our computation. Comparison with more exact Finite Difference Eikonal solvers for both 1-D and 2-D models show excellent agreement. We have used traveltime tables computed from interval elliptic velocity and anisotropic parameter kappa to perform pre-stack time or depth migration in VTI media. We have applied these techniques successfully to a 2D marine seismic reflection data from the Gulf of Mexico resulting in improved images of a hydrocarbon reservoir zone.

DE: 0900 EXPLORATION GEOPHYSICS
DE: 0902 Computational methods, seismic
DE: 0910 Data processing
DE: 0935 Seismic methods (3025)
SC: S
MN: Fall Meeting 2000