Limited-aperture acquisition compensation for shot profile imaging
Friday, October 12, 3PM – 4PM
Can Evren Yarman
The high dimensionality and ill-posedness of the seismic imaging inverse problem in complex areas make its solution challenging. There are two main reasons for this: first is the limited and irregular acquisition of the seismic experiment, second is the complexity of the overburden. Combined, these two effects will produce irregular illumination of the subsurface, possibly even shadow zones. Various approaches have been proposed to attempt to compensate for these two effects under true amplitude imaging for shot-profile migration. Among these, numerical approximation of the Hessian matrix for each frequency in a least-squares inversion solution is computationally demanding. Demigrataion-migration methods require a migrated image, a reflector model or diffractor model, which are at least 3 times costly than shot profile migration and may be susceptible to interpretation errors. Current analytic methods are limited either to zero offset acquisition geometry, or constant velocity background model, both of which don’t apply to complex earth models and/or large aperture acquisition geometries. We present a randomization based computationally efficient method to compute shot-profile migration weights that enhance a given imaging condition by compensating for illumination due to limited-aperture receiver acquisition geometry. Our method works with complex earth models as well as higher aperture acquisition geometries, which we will demonstrate with synthetic and real data examples.
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