Multi-realisation 4D noise attenuation

Multiple timelapse realisations produced using wavefield separation, data selection, or diverging processing flows are combined using powerful noise-reducing data weights formulated using the 3D images as well as the 4D differences. The result separates 4D signal from incoherent 4D noise and also 4D noise that is coherent across multiple realisations of 4D difference but not repeated in both baseline and monitor 3D images (e.g. residual multiple in the monitor). Examples using Broadseis base and monitor from the North Sea, and towed-streamer base and OBN monitor from deep water offshore Angola, show considerable uplift to the final 4D difference.