Model‐based decimation of input data for delayed‐shot/plane‐wave migration for the purpose of subsalt velocity model building

The process of subsalt velocity model building often makes use of wave-equation migration scans using a series of perturbed velocity models. As these methods require significant computer resources, reducing the cost is a concern to the depth imager. Historically and from a practical point of view, decimation of the input data using a regular or random pattern of data selection is frequently applied but does not make use of any available illumination criteria. In this paper, we present an alternative methodology that offers a way to optimize the decimation criteria according to P-values for delayed-shot/plane-wave type migrations. Local Tau-P analysis of wave equation demigrated seismic events is used to drive the P-value selection and honor illumination effects.