Common-reflection-surface stack - a real data example

The simulation of a zero-offset (ZO) stack section from multi-coverage refl ection data is a standard imaging method in seismic processing. It signific antly reduces the amount of data and increases the signal-to-noise ratio du e to constructive interference of correlated events. Conventional imaging m ethods, e.g., normal moveout (NMO)/dip moveout (DMO)/stack or pre-stack mig ration, require a sufficiently accurate macro-velocity model to yield appro priate results, whereas the recently introduced common-reflection-surface s tack does not depend on a macro-velocity model. For two-dimensional seismic acquisition, its stacking operator depends on three wavefield attributes a nd approximates the kinematic multi-coverage reflection response of curved interfaces in laterally inhomogeneous media. The common-reflection-surface stack moveout formula defines a stacking surface for each particular sample in the ZO section to be simulated. The stacking surfaces that fit best to actual events in the multi-coverage data set are determined by means of coh erency analysis. In this way, we obtain a coherency section and a section o f each of the three wavefield attributes defining the stacking operator. Th ese wavefield attributes characterize the curved interfaces and, thus, can be used for a subsequent inversion. In this paper, we focus on an applicati on to a real land data set acquired over a salt dome. We propose three sepa rate one-parametric search and coherency analyses to determine initial comm on-reflection-surface stack parameters. Optionally, a subsequent optimizati on algorithm can be performed to refine these initial parameters. The simul ated ZO section obtained by the common-reflection-surface stack is compared to the result of a conventional NMO/DMO/stack processing sequence. We obse rve an increased signal-to-noise ratio and an improved continuity along the events for our proposed method - without loss of lateral resolution. (C) 1 999 Elsevier Science B.V. All rights reserved.