Análise de atributos sísmicos instantâneos: porção central da Bacia de Campos

Abstract

The geophysical method of reflection seismic has contributed fundamentally to the oil industry to achieve the current scenario of hydrocarbon exploration. However, there is a continuous need to improve techniques that aim to contribute even more precisely to the definition of lithological and petrophysical aspects of reservoirs. Seismic attribute analysis is an additional tool in the characterization of petroleum systems, as it allows a better identification of heterogeneities present in sedimentary packages. Seismic attributes are generated in order to highlight some particular characteristic of the medium, which sometimes may not be seen in standard imaging. Their analysis is applied in the interpretation from regional depositional systems to the detailing of subtle features in the structural and stratigraphic mapping of the rocks. The instantaneous seismic attributes (or amplitude) are calculations applied to the post-stack seismic data based on the concept of complex seismic trace, exploring its imaginary part (quadrature component) from the application of the Hilbert Transform. These attributes can be collectively termed instantaneous because they concisely and quantitatively describe the seismic waveform at any sampling point. The Campos Basin, the focus of the study, consists of a passive margin basin, generated through the ripping off of the supercontinent Gondwana. The generation, migration and accumulation of hydrocarbons in this basin is quite diverse in terms of trapping, whether structural, stratigraphic, mixed or saline diapiric. The Campos Basin's oil potential has been known since the 1970s by drilling wells in post-salt turbiditic reservoirs. The present work made use of the technique of instantaneous seismic attributes and similarity in Campos Basin post-stack seismic (2D) sections provided by BDEP/ANP. With technological advances and greater acquisition of seismic data, hydrocarbons have been increasingly explored in deep and ultra-deep waters, which culminated in the discovery of reservoirs associated with pre-salt microbial carbonates. The objective of this work was to complement and enhance previously processed and interpreted structural and stratigraphic features and, in addition, to obtain information linked to the true geometries of the main seismic horizons, in order to support studies related to the tectono-sedimentary evolution of the basin.