Camorim field is located offshore Sergipe State, Brazil. The producing section includes 150 m of Cretaceous conglomerates and coarse to very fine-grained sandstones, interbedded with siltstones and shales. Within this interval, six pools are recognized based on log correlation and facies analysis. The field has an area of 25 km² and the reservoir average depth is 1,900 m.

Twenty-eight development wells were drilled to exploit the pools and the productivity ranges from 100 to 1 m³/day/well. Reservoir geology and performance were analyzed by a multidisciplinary group composed of development geologists, sedimentologists, production engineers, and log analysts.

The reservoirs were fully cored in five wells and the correlation between rock and log responses allowed facies mapping throughout the field. The depositional model is interpreted as an alluvial-fan complex prograding toward a lacustrine environment. Log analysis and correlation between lithofacies and permeability allow the estimation of reservoir quality at any point of the pools.

Together with reservoir quality, the oil properties are recognized as controlling the productivity of the wells. At reservoir conditions, oil viscosity ranges from 1 to 5 cp (centipoises). Data at tank conditions show that density (18 to 37° API) and viscosity (10 to 200 cp) increase eastward throughout the field and from the upper to the lower part of the blocks.

To support reservoir simulation, permeability is calculated for each well as a weighted geometric mean based on the thickness of each of the three reservoir facies: conglomerates (200 md), coarse to medium-grained sandstones (23 md) and fine to very fine-grained sandstones (1 md). This model explains the initial and long-term well performances and the pressure behavior of the reservoirs.

End_of_Article - Last_Page 612------------