Velocity Inversion by Coherency Optimization
RICE UNIV HOUSTON TX DEPT OF COMPUTATIONAL AND APPLIED MATHEMATICS
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We introduce an approach to velocity and reflectivity estimation based on optimizing the coherence of multiple shot-gather inversions of reflection seismograms. The resulting algorithm appears to avoid the severe convergence difficulties reported for output nonlinear least-squares inversion. We describe in detail an algorithm appropriate for the layered acoustic model, using the convolutional model of the plane-wave ptau seismogram. We give a theoretical analysis and numerical evidence that coherency optimization, as defined here, yields stable and reasonably accurate estimates of both velocity trend and reflectivity, by exploiting reflection phase moveout and amplitudes in a computationally efficient way. We also indicate how the approach may he modified to apply to laterally heterogeneous acoustic models, and more briefly to determination of elastic models and source parameters as well.
- Numerical Mathematics