Multicomponent ocean bottom cable (OBC) technology reestablishes the
use and importance of converted wave (*PS*) data, yet
opens the door for a series of new and existing problems with
*PS* data.
Irregular acquisition geometries are a serious impediment for
accurate subsurface imaging. Irregularly sampled
data affects the image with amplitude artifacts and phase
distortions. Irregular geometry problems are more
evident in cases in which the amplitude information is one of the
main goals of study.
For *PS* data, this problem is crucial since most
of the *PS* processing focuses on the estimation of rock
properties from seismic amplitudes.

The application of inverse
theory satisfactorily regularizes acquisition geometries of
3D prestack seismic data Albertin et al. (1999); Audebert (2000); Bloor et al. (1999); Chemingui (1999); Duijndam et al. (2000); Duquet et al. (1998); Nemeth et al. (1999); Rousseau et al. (2000).
For
*PP* data, there are two distinct approaches to apply:
1) data regularization before migration and 2) irregular
geometries correction during migration. Biondi and Vlad
2001 combine the advantages
of the previous two approaches. Their methodology regularizes
the data geometry before migration, filling in the acquisition
gaps with a partial migration operator. The operator exploits the
intrinsic correlation between prestack seismic traces.
The partial migration operator used is Azimuth Moveout.

The recent development of a converted wave Azimuth Moveout (PSAMO) operator Rosales and Biondi (2001) that preserves amplitudes and is fast, enables the extension of Biondi and Vlad's 2001 methodology for converted waves data. Therefore, a complete and accurate geometry regularization is now possible for OBC seismic data.

This paper extends already existing methodologies for
*PP* regularization in order to handle *PS* data.
Due to the asymmetry of ray trajectories in *PS* data,
there are more elements to consider in order to solve for
irregular geometry problems.
Our method for *PS* data regularization uses a *PS* Azimuth Moveout operator (*PS*-AMO)
Rosales (2002) in order to preserve
the resolution of dipping events and correct for the
lateral shift of the common conversion point.

Our methodology depends on the ratio between
the *P* and the *S* velocities ().
It also depends on the continuity of the events in the
common midpoint gathers. These situations make our
regularization an iterative procedure that stops
where the difference between the previous and the
actual sections is relatively small.

We will present a summary of Biondi and Vlad's
2001 methodology for solving the
irregular geometry problem using a preconditioned-regularized
least-squares scheme. We present and discuss how this method
can be extended to handle *PS* data and implement this method
on a portion of a real 3D OBC data set.

11/11/2002