Palaeogeographical, Palaeoclimatic and Burial History Controls on the Diagenetic Evolution of Reservoir Sandstones: Evidence from the Lower Cretaceous Serraria Sandstones in the Sergipe–Alagoas Basin, NE Brazil

  1. Sadoon Morad
  1. A. J. V. Garcia1,†,
  2. S. Morad1,
  3. L. F. de Ros1,‡ and
  4. I. S. Al-Aasm2

Published Online: 17 APR 2009

DOI: 10.1002/9781444304893.ch5

Carbonate Cementation in Sandstones: Distribution Patterns and Geochemical Evolution

Carbonate Cementation in Sandstones: Distribution Patterns and Geochemical Evolution

How to Cite

Garcia, A. J. V., Morad, S., de Ros, L. F. and Al-Aasm, I. S. (1998) Palaeogeographical, Palaeoclimatic and Burial History Controls on the Diagenetic Evolution of Reservoir Sandstones: Evidence from the Lower Cretaceous Serraria Sandstones in the Sergipe–Alagoas Basin, NE Brazil, in Carbonate Cementation in Sandstones: Distribution Patterns and Geochemical Evolution (ed S. Morad), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304893.ch5

Author Information

  1. 1

    Sedimentary Geology Research Group, Institute of Earth Sciences, Uppsala University, Norbyvägen 18B, 5-752 36, Uppsala, Sweden

  2. 2

    Department of Earth Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada

  1. Universidade do Vale do Rio dos Sinos—UNISINOS, Sedimentary Geology Program, Av. Unisinos, 950, CEP 93.022-000, São Leopoldo, RS, Brazil

  2. Universidade Federal do Rio Grande do Sul, Instituto de Geociências, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil

Publication History

  1. Published Online: 17 APR 2009
  2. Published Print: 29 MAY 1998

ISBN Information

Print ISBN: 9780632047772

Online ISBN: 9781444304893

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Keywords:

  • palaeographical, palaeoclimatic and burial history controls on diagenetic evolution of reservoir sandstones;
  • Serraira Formation (Early Cretaceous);
  • palaeographical reconstruction of Serraira Formation;
  • detrital composition and provenance;
  • diagenetic evolution and burial history;
  • syn-rift subsidence and mesodiagenesis

Summary

The Serraria Formation (Early Cretaceous) was deposited prior to the Proto-Atlantic Rift rupture by a braided fluvial system crossing a wide cratonic basin from N to NW, and is an important hydrocarbon reservoir in several oilfields in the Sergipe–Alagoas Basin, northeastern Brazil. Four diagenetic domains with different palaeogeographical, palaeoclimatic and lithofacies settings, as well as burial histories, were distinguished, which roughly correspond to original locations in the fluvial depositional system. During eodiagenesis (144–140 Ma) the palaeoclimate was arid to semi-arid and resulted in the precipitation of vadose and phreatic calcite (δ13CPDB = −6.7‰; δ18OPDB = −8.2‰) in the proximal deposits and phreatic dolomite (δ13CPDB = −8.5 to −3.1‰; δ18OPDB = −8.7 to −6.7‰) in the distal deposits. Both calcite and dolomite formed in the middle deposits. During the syn-rift subsidence and mesodiagenesis (≈140−118 Ma), new generations of calcite (δ13CPDB = −11.2 to −3.5‰; δ18OPDB = −13.6 to −11.5‰) and dolomite (δ13CPDB = −11.2 to −2.6‰; δ13OPDB = −10.6 to −4.1‰) precipitated in the proximal (maximum T ≈ 100°C) and distal (maximum T ≈ 70−100°C) domains, respectively. The best reservoirs of the Serraria Formation are sandstones of the distal area that were affected by pervasive telogenetic dissolution of carbonate cements and silicates, and the formation of kaolinite. This occurred mostly at the beginning of the post-rift uplift (114–74 Ma), when warm and humid conditions prevailed. The post-rift subsidence and mesodiagenesis (115 Ma until now) resulted in further precipitation of calcite and dolomite with similar isotopic values to the syn-rift cements (δ13CPDB = −12.3‰; δ18OPDB = −8.2 to −6.9‰) in the proximal and distal domains, respectively. Other mesogenetic processes include dickitization and illitization of kaolinite, illitization and chloritization of smectite, albitization of feldspars, and precipitation of quartz cement. Recent exposure and telodiagenesis, affecting sandstones along margins of the rift basin in the middle domain, is resulting in dissolution of silicates and precipitation of quartz, chalcedony and iron oxides.