f Borehole guided dephasing of seismic data: a case history

The dephasing of seismic data is an important part of seismic data processing, particularly when the objective is to obtain information about the underlying stratigraphy. It is an important step in botte AVO analysis and most inversion schemes . The method used in this study is based on the scheme introduced by White (1980) and further refined by Walden and White (1984). It generates a wavelet by matching a seismic trace with a broadband synthetic derived from borehole information at the same location. This is used in turn to generate an allpass filter to remove the phase of the wavelet from the seismic data. Errors in the relative positioning of the seismic and borehole data are taken into account by searching in botte time and space within a limited part of the seismic data volume for the trace segment that best matches the broadband synthetic. QC information is generated along with the estimated wavelet, and can be used as an aid to parameter selection. In this study, results are presented illustrating the use of this technique, along with additional QC checks, on real data from the North Sea.