Shallow Water Demultiple

Abstract

ASEG 2010 In this paper, we present a workflow that involves first attenuating short-period water-layer related multiples (WLRMs) – a process that we term shallow water demultiple (SWD); and then suppressing other long- period free surface multiples using conventional SRME. SWD is a wavefield-consistent method that first makes use of WLRMs in the data to reconstruct the missing water-bottom primary reflection and then uses the reflection for predicting shallow WLRMs. It is data driven and takes into account the spatial varying nature of subsurface structures. Since the WLRM model predicted by SWD has similar amplitude and phase as the input data, very short matching filters, which are not possible if deconvolution is used, can be utilised in the adaptive subtraction process. We demonstrate, through real-data examples, that our workflow provides an optimal multiple attenuation solution in shallow water environment in comparison with conventional methods such as -p deconvolution or SRME alone.