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Reduction in Bin Size of Seismic Data for Sharper Definition of Geologic Features


Ideally, seismic data should be acquired at high spatial and temporal sampling, so that the small subsurface features of interest can be clearly seen on the seismic display. Such interpretation is easiest when the geological features of interest are uniformly illuminated, which in turn is possible by recording the scattered seismic wavefield on a uniform surface grid. The “nominal grid” is defined by the source-to-source spacing within a shot line and the geophone-group-to-geophone-group spacing within a receiver line. One can also increase the trace density by reducing the spacing between shot lines and between receiver lines. Once acquired, data processing workflows are designed to retain the highest possible lateral and vertical resolution of the geologic target. Because of the different ray paths, dense acquisition (closer source and receiver lines) provides greater leverage against backscattered ground roll and decreased migration artifacts. Uniform acquisition results in increased lateral continuity of amplitudes that otherwise may be contaminated by acquisition footprint. While there is no substitute for acquiring good quality seismic data that has the above mentioned qualities, it is possible to mimic or address some of the problems that crop up due to the sub-optimum parameterization used in the acquisition, during processing of the data. It is possible to regularize the offsets and azimuths of the input seismic data during processing by way of 5D interpolation, which then aids the computation of seismic attributes. In this presentation we demonstrate the results of reducing the bin size of the seismic data as part of the 5D interpolation process. A comparison of the seismic amplitude data before and after bin size reduction exhibits clearer seismic signatures corresponding to the features of interest that can be seen on the coherence or curvature horizon slices. One can notice the enhanced resolution of the faults and the suppression of the acquisition footprint. Stratigraphic features such as a distributary channel system seen on the coherence slices may be well imaged at the nominal grid size but the interpolated surface data at reduced bin size provides much sharper individual channel limbs. Such enhanced quality imaging of data in terms of suitable seismic attributes helps squeeze out more information from the seismic data and contribute in a generous way to the overall interpretation of the data as well.