Common-angle migration and oriented waves in the Phase-Space (x, p) (original) (raw)

Measurement of convergence in plane-wave migration.

We have developed a FOCI-driven imaging code that implements a plane-wave migration algorithm. This algorithm produces images that are interpretable with a fraction of the computation time required for a full prestack migration. Additionally, the image may be selectively refined to maximize the benefit of computation time. To guide this refinement, we propose a measure ("residual") of the convergence of the imaging. This method selects a region of the image to monitor. Then within this region, the l 2 norm of the difference between two successive plane-wave stacks normalized by the l 2 norm of the first plane-wave stack is calculated. This residual decreases rapidly while the image is improving and approaches zero as the image approaches its limit. We have implemented this plane-wave code in order to facilitate highly-efficient prestack wave-equation depth migration. Although plane-wave migration is well-known in the seismic community, we intend to use this code as a starting point for future theoretical developments.

Converted-wave azimuth moveout

GEOPHYSICS, 2006

A new partial-prestack migration operator to manipulate multicomponent data, called converted-wave azimuth moveout (PS-AMO), transforms converted-wave prestack data with an arbitrary offset and azimuth to equivalent data with a new offset and azimuth position. This operator is a sequential application of converted-wave dip moveout and its inverse. As expected, PS-AMO reduces to the known expression of AMO for the extreme case when the P velocity is the same as the S velocity. Moreover, PS-AMO preserves the resolution of dipping events and internally applies a correction for the lateral shift between the common-midpoint and the common-reflection/conversion point. An implementation of PS-AMO in the log-stretch frequency-wavenumber domain is computationally efficient. The main applications for the PS-AMO operator are geometry regularization, data-reduction through partial stacking, and interpolation of unevenly sampled data. We test our PS-AMO operator by solving 3D acquisition geometr...