Guarujá Formation

Guarujá Formation
Stratigraphic range: Early Albian
~113–108 Ma
Type Geological formation
Unit of Camburi Group
Underlies Itajaí-Açu Fm., Juréia Fm.
Overlies Ariri Formation
Thickness up to 2,500 m (8,200 ft)
Lithology
Primary Limestone
Other Marl
Location
Coordinates 26°6′S 43°43′W / 26.100°S 43.717°W / -26.100; -43.717Coordinates: 26°6′S 43°43′W / 26.100°S 43.717°W / -26.100; -43.717
Region Santos Basin, South Atlantic
Country  Brazil
Type section
Named for Guarujá

Location of the Santos Basin

The Guarujá Formation (Portuguese: Formacão Guarujá) is a geological formation of the Santos Basin offshore of the Brazilian states of Rio de Janeiro, São Paulo, Paraná and Santa Catarina. The predominantly calcarenite formation with marls dates to the Early Cretaceous period; Early Albian epoch and has a maximum thickness of 2,500 metres (8,200 ft). The formation is the second-most important post-salt reservoir rock of the Santos Basin.

Etymology

The formation is named after the city of Guarujá, São Paulo.

Description

The Guarujá Formation is 832 to 2,500 metres (2,730 to 8,202 ft) thick,[1] and consists of oolitic calcarenites, which laterally grade to greyish ochre and brownish grey calcilutites and grey marls. These facies are interbedded with the alluvial clastics of the Florianópolis Formation. The Guarujá name is restricted to the lowest limestone intercalation, previously named Lower Guarujá by Ojeda and Ahranha in Pereira and Feijó (1994). The microfacies indicate a tidal flat to shallow lagoon and open carbonate platform depositional environment. The age based on planktonic foraminifera and pollen is Early Albian.[2]

Petroleum geology

The formation is the second-most important post-salt reservoir rock of the Santos Basin,[3] after the Itajaí-Açu Formation.[4][5]

Field Year Operator Reserves (in place)
Notes
Cavalo Marinho2001Petrobras25.04 MMbbl (3.981×10^6 m3)
Caravela1992Petrobras48.81 MMbbl (7.760×10^6 m3)
Caravela Sul1991Petrobras5 MMbbl (790×10^3 m3)
Coral1990Petrobras22.57 MMbbl (3.588×10^6 m3)
Estrela do Mar1990Petrobras15.16 MMbbl (2.410×10^6 m3)
Tubarão1988Petrobras30 MMbbl (4.8×10^6 m3)

See also

References

  1. Kiang Chang et al., 2008, p.32
  2. Clemente, 2013, p.22
  3. Contreras, 2011, p.34
  4. 1 2 3 4 5 6 Santos Basin Fields
  5. Vieira, 2007, p.9
  6. Juarez, 2013, p.14
  7. ANP Yearbook, 2014, p.30
  8. Coral Field: Case History in Oil Producing Albian Carbonates in Santos Basin, Brazil
  9. Estrela do Mar, Cavalo Marinho oil output by 2007
  10. Juarez, 2013, p.11

Bibliography

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