... to parallelize. A powerful tool for time imaging consists of a series of prestack time migrations and demigrations. We have applied multiparameter stacking techniques to obtain an initial time-migration velocity model. The velocity model building proposed here is based on the kinematic wavefield attributes...

...Amr Ibrahim; Mauricio D. Sacchi ABSTRACT Stolt migration is a Fourier-domain imaging operator that assumes a constant-velocity media. We have developed a multivelocity version of the Stolt migration and demigration operators to derive a transform that can decompose seismic data into a sparse...

...Wiktor Waldemar Weibull; Børge Arntsen ABSTRACT The forward and inverse process of seismic migration and demigration or remodeling has many useful applications in seismic data processing. We evaluated a method to reobtain the seismic reflection data after migration, by inverting the common image...

... because we integrate for half of the time only (until t = 0 ). Equation 9 is not an exact result; note the approximation detailed in Appendix A . END This provides the initial migrated section, function of h : FOR EACH TIME DELAY DEMIGRATION IN THE INITIAL MODEL...

...Hervé Chauris; Truong Nguyen Abstract Curvelets can represent local plane waves. They efficiently decompose seismic images and possibly imaging operators. We study how curvelets are distorted after demigration followed by migration in a different velocity model. We show that for small local...

... can be found in “Seismic modeling by demigration” in the July–August issue of G eophysics . A new process in seismic reflection imaging called demigration has been designed as the inverse of migration and is, thus, easily confused with forward modeling . This paper will clarify...

...Lúcio T. Santos; Jörg Schleicher; Martin Tygel; Peter Hubral Abstract Kirchhoff-type, isochron-stack demigration is the natural asymptotic inverse to classical Kirchhoff or diffraction-stack migration. Both stacking operations can be performed in true amplitude by an appropriate selection of weight...

...Herman H. Jaramillo; Norman Bleistein Abstract The Kirchhoff approximation provides a representation of seismic data as a summation of imaged data along isochron surfaces (demigration). The asymptotic inversion of this representation provides a migration as a summation of seismic data along...

...Joerg Schleicher; Peter Hubral; Martin Tygel; Makky S. Jaya Abstract The size of the aperture has an important influence on the results of (Kirchhoff-type) migration and demigration. For true-amplitude imaging, it is crucial not to have apertures below a certain size. For both the minimum migration...

... time interpretations are still used and are 'demigrated' using the Kirchhoff time migration equations. This backs out the effect of the time migration prior to a ray depth migration and enables the lateral shifts between the time migrated image and a depth migrated image to be quantified. These shifts...

... after migration and demigration. One-way wave-equation migration would automatically damp high-slope components in the evanescent region while accurately handling the other components. Thus, the migration velocity can be tuned to naturally trap a given range of high-slope components into the evanescent...