Seismic conditioning and attenuation of high-angle coherent noise in a mixed carbonate and siliciclastic setting, Campos Basin, offshore Brazil: A case study

Abstract

We demonstrate the use of two industry-standard, noise-attenuating algorithms, [Formula: see text] and [Formula: see text] filtering, to attenuate coherent noise, improve event continuity, and obtain more reliable interpretation within the Pampo field, Campos Basin, offshore Brazil. We analyze 3D seismic data for noise type and associated maximum dip, and then determine optimal attenuating parameters required by the algorithms. In the crossline direction, coherent noise with dips as high as 16 to 18 ms/trace in the data masks real reflected signals. In the inline direction, the noise exhibited an approximately zero dip. The filtering process eliminated noise trains and improved event continuity, as well as obtained better well-to-seismic tie. The output wavenumber associated with noise trains is less than the Nyquist wavenumber; therefore, we conclude that the noise is not related to spatial aliasing, but to other undetermined sources. Though the noise occurs within the entire data volume, it is most severe in the vicinity of the carbonate platform. By eliminating linear noise that masquerades as geologic structures, we obtain better imaging of the Albian succession and the younger Cretaceous turbidite sequences, as well as the top of Aptian salt. The result is a better interpretation.