Multiple investigations by synthetic modeling and wave equation attenuation: North West Shelf of Australia data example

Abstract

Seismic data acquired from the North West Shelf (NWS) of Australia contains strong multiples. Water bottom peg‐legs generated from the shallow water bottom have similar moveout with primaries from deeper reflectors. Move‐out driven demultiple methods such as Radon de‐multiple often fail in this situation. Alternative demultiple solutions are the wave‐equation methods of Surface Related Multiple Elimination (SRME), Iterative SRME (ISRME), and Interbed Multiple Elimination (IME). This paper addresses the problem of peg‐leg multiples that heavily contaminate the shallow water seismic data from the NWS. To understand these multiples full‐wavefield and ray‐traced synthetics were generated. Radon demultiple and SRME were both tested on the synthetics. We conclude that SRME succeeded whilst Radon failed in peg‐leg multiple dominant data. We demonstrate the multiple attenuation success on real data using the SRME method. The final image is an outstanding result compared with processing using other demultiple methods.