--> ABSTRACT: Brazilian Turbidite Reservoirs: Heterogeneity Study from Outcrops to Subsurface, by Marco A. S. Moraes and Carlos H. L. Bruhn; #91030 (2010)

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Brazilian Turbidite Reservoirs: Heterogeneity Study from Outcrops to Subsurface

Marco A. S. Moraes, Carlos H. L. Bruhn

Study of turbidite outcrops in several Brazilian formations permitted the construction of reservoir models that have been successfully applied in oil and gas fields. Five turbidite reservoir types were characterized. (1) Channel-levee complexes: groups of elongate sandstone or conglomerate bodies, commonly rich in rip-up clasts, each about 500 m wide, ranging in thickness from 5 to 50 m. These are typical of canyon-filling sections of different basins. (2) Channelized lobe complexes: associations of thick (up to 50 m) and relatively continuous (> 10 km2) sand bodies of mainly massive sandstones. This type occurs predominantly in the Campos basin and contains about 50% of Brazil's oil reserves. (3) Non-channelized lobe complexes: successions of classical turb dites, each sandstone layer tens of centimeters thick. These reservoirs are greater than 20 km2 in area and have small thickness variations within a hydrocarbon field. They are widely distributed in the Brazilian basins. (4) Fringes: sand-shale sequences with the sandstone layer only a few centimeters thick. These are widely distributed in several basins. (5) Aprons: thick, subaqueous clastic wedges composed of conglomerates and coarse-grained sandstones deposited in slightly shallower water settings associated with faulted margins of rift basins.

These reservoir models are of great applicability for well-to-well correlation and for the prediction of the degree of connection between adjacent flow units. Outcrop studies also provided more realistic input data for reservoir simulation studies, thus leading to better predictions of fluid flow patterns.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.