Kurt J. Marfurt, Ron M. Sheet, John A. Sharp, Jim C. Ward,
Gordon J. Cain, and Mark G. Harper
Seismic coherency has proven to be very effective in delineating geologic faults as well as considerably more subtle stratigraphic features including channels, canyons, slumps, levees, dewatering patterns and pinnacle reefs. Unfortunately, seismic coherency estimates, which quantitatively measure the similarity or dissimilarity of adjacent traces in 3-D, is particularly sensitive to coherent noise that passes through the stack array. They are equally sensitive to dissimilarities in fold, offset distribution and azimuth distribution introduced through the 3-D binning process. We define both these effects to be the acquisition footprint. This acquisition footprint is usually unattenuated and often accentuated by aliased dip moveout and post stack migration operators.
While one may easily eliminate the acquisition footprint on the seismic coherency time or depth slices using conventional spectral analysis, such filtering is inappropriate for solid angle dip maps, as well as for conventional phase, envelope, frequency and bandwidth maps where we need to preserve the DC bias. We show that simple 3-D true amplitude dip filtering of the (t,x,y) seismic data volume can be most effective in minimizing the detrimental effect of the acquisition footprint on 3-D seismic attributes for both conventional marine and land data acquisition geometries.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California