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Seismic Characterization of the Pre-Salt Rifted Section of the Lagoa Feia Group, Campos Basin, Offshore Brazil

Abstract

The Exploration and development of what it is commonly known the “pre-salt” layer, offshore SE Brazil, is in its infancy but with reservoirs buried below as much as 3000 meter of salt, the pre-salt play presents a multifaceted deep-water scenario that is bringing new challenges to seismic interpretation in offshore Brazilian exploration and production. Reservoirs in this domain are complex, heterogeneous with layered carbonates which makes accurate reservoir characterization very challenging. By using the existing 2D seismic dataset and two deep well logs and core information, we propose a seismic intepretation of the Lagoa Feia formation and propose a seismic facies analysis of some sub units of the Lagoa Feia. Our study here deals with the seismic characterization of the stratigraphy of a lacustrine section from the Lagoa Feia Group (Winter et al., 2007) in the Campos Basin, which extends over an area of 100,000 km2. Different pre- syn- and post-rift seismic stratigraphic units, with corresponding bounding surfaces were defined recognized, mapped and based on four seismic textures we map the main lithological package in the rift section: border fault deposits; fine grain-dominated re-sedimented deposits; coarse grain-dominated carbonate rich re-sedimented deposits; and an intrusive wipe-out zones affecting all the pre-salt unit. By proposing this seismic classification across the pre salt campos basin units this work represent an introductory step to a facies classification applicable at regional level in the SE Brazil offshore area.