Interbed demultiple using Marchenko redatuming on 3D field data of the Santos basin

Abstract

We apply Marchenko redatuming using an adaptive double-focusing method to 3D field data of the Santos basin, Brazil. This method was already successfully applied to 2D field data and we now study the acquisition geometry and preprocessing requirements in 3D. We start from 3D synthetic data modeled on a dense grid of colocated sources and receivers and decimate down to a realistic NAZ streamer acquisition. The synthetic tests show that the sail line spacing and the missing outer cables are the acquisition parameters with the strongest effect on Marchenko redatuming. We can interpolate for the sail line spacing and the near offsets, but the missing outer cables are unfortunately a limitation of the acquisition. After applying the proposed interpolation to 3D field data, interbed multiples are successfully predicted and subtracted from the target area, resulting in a significant improvement in the geological interpretation. Naturally, the pre-processing requirements and challenges strongly depend on the acquisition geometry and the geology of the area under investigation (e.g. water depth, shape of the overburden, maximum dip). Hence, these tests only give a general idea about the limitations of 3D Marchenko redatuming