Mario Carminatti¹, Celso C. Martins²
(1) Petrobras, Rio de Janeiro, Brazil
(2) Petrobras/E&P/Gerex, Rio de Janeiro, Brazil

Abstract: An overview of the architectural elements of sand-rich deep-water depositional systems: examples from Atlantic Brazilian basins

Sand-rich deepwater depositional systems have been considered the most important petroleum play targets in the ever increasing deepwater exploration activities along the Brazilian Atlantic basins.

Although the grain-size distribution of these systems vary from gravel- to mud-rich, sand-rich systems are responsible for circa 75% (14 Gboe) of the Brazilian total oil reserves. Sand-rich deepwater depositional systems present a variety of genetic sedimentary facies associations forming different assemblages of architectural elements and, as a consequence, different depositional systems, eaach one with characteristic external geometries.

The systematication of a discrete number of characteristic geometries of such sand-rich deepwater systems may lead to better predictions of important economic parameters such as volumes of porous sandstones (sand/shale ratio), porosity and permeability values, geometry and connectivity of the reservoirs, production flows, pressure driving mechanisms and recovery factors. The Brazilian experience on a varied spectrum of passive margin basins provides an ideal situation for the build up of a significant data bank on deep water depositional systems.

This work will focus on the understanding of sand-rich deepwater depositional systems on the exploration scale, based upon the integration of 3D seismic, cores and wireline log data. Emphasis will be given to their variabilities in terms of architectural elements and their influence on the economic evaluations.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana