


 Fast 3D velocity updates using the prestack exploding reflector model  

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We show that prestack explodingreflector model synthesizes wavefields that provides migrated images with correct kinematics while decreasing the data size. Data reduction is achieved by combining the modeling experiments and is controlled by the number of subsurface offsets that will be computed during arealshot migration of PERM data. Implicit to PERM is that reflectors must be identified. 3D Prestack interpretation can be cumbersome, but it allows, for instance, avoiding the use of reflectors with low signaltonoise ratios in migration velocity estimation. In 3D, the size of PERM data can be one order of magnitude smaller if crossline subsurfaceoffsets are to be computed. Further data size reduction by one order of magnitude is achieved if the initial conditions are computed with commonazimuth migration.
In addition to the reduced data size, the definition of the velocity model is greatly accelerated due to targetoriented nature of PERM, which allows wavefields to be propagated only in the region where the velocity is to be updated. The 3D example with real data confirms the accuracy of the velocity solution achieved by migration velocity analysis by wavefield extrapolation using PERM wavefields.



 Fast 3D velocity updates using the prestack exploding reflector model  

Next: Acknowledgments
Up: Guerra and Biondi: Fast
Previous: 3D velocity update example
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