Seismic acquisition footprint: modelling and mitigation

Joanna Kathleen Cooper

Acquisition footprint is a phenomenon occurring in seismic images whereby amplitude variations relate to the survey geometry, rather than solely to the physical properties of the subsurface. In this study, 2D and 3D exhaustive datasets, exhibiting no spatial aliasing in either source or receiver gathers, were produced via numerical modelling and were subsequently decimated to examine the effect of spatial sampling on acquisition footprint. The exhaustive and decimated datasets were processed using common-midpoint stacking, poststack migration, and prestack migration. Footprint artefacts were found to depend strongly on the processing flow applied to the data. Footprint consisting of spatially periodic amplitude variations was prominent in only the decimated datasets, and was most severe in prestack-migrated data. In 2D, spatial aliasing of receiver gathers was coincident with the presence of footprint. Delta-ratio weighting, a prestack migration weighting scheme developed in the course of this study, was found to reduce footprint artefacts significantly.