Broadband Verses Conventional Marine Seismic: The Importance of Compensating for the Earth Filter

Broadband seismic enables us to move closer towards the ideal goal of imaging, which is to provide the true response of the earth. The potential of broadband seismic can only be fully realised if the effect of various earth filters are accurately compensated for, which often requires some attenuation estimation such as effective Q. This is particularly true in sub-salt and sub-basalt settings where locally strong attenuation of the seismic signal occurs. Here we evaluate the differences in spectral content between broadband and conventional marine seismic through simple synthetic earth models in an attenuating medium. Without compensating for effective Q, we demonstrate that the top and base of a thin layer at depth may not be resolvable in the broadband case. We then describe the application of the pre-stack Q inversion method to derive a spatially varying interval consistent effective Q field from data in the Faroe-Shetland Basin. Application of this field demonstrates a substantial uplift in resolution within the prospective intra-basalt Flett formation.