CONCLUSION

We have presented a new technique for processing wide-azimuth surveys that accurately images 3-D seismic data while preserving relative amplitudes describing the offset and azimuth-dependent reflectivity function. The technique is based on organization of the data into common-azimuth (CA) and common-offset (CO), which allows interpolation to a regular grid before imaging. The method addresses both issues of algorithmic accuracy and proper handling of irregular geometry and therefore allows for reliable AVO analysis on migrated data. We applied this technique to invert for a synthetic reflectivity model which simulates a real 3-D wide-azimuth land survey over a fractured reservoir. Results showed that Kirchoff migration was unable to preserve amplitudes in case of sparse and irregular coverage. The AMO transformation before migration succeeded in reconstructing the data as regular gridded cubes while preserving its amplitude information for imaging. We conclude that (a) interpolating seismic data prior to migration is a promising method for preserving amplitude information; (b) AMO is an effective tool for organizing the data for common-azimuth processing while correcting for the sparse and irregular coverage in wide azimuth 3-D acquisition.