Permeability and Porosity Evolution in Dolomitized Upper Cretaceous Pelagic Limestones of Central Tunisia

  1. Bruce Purser,
  2. Maurice Tucker and
  3. Donald Zenger
  1. M. H. Negra1,
  2. B. H. Purser2 and
  3. A. M'Rabet3

Published Online: 14 APR 2009

DOI: 10.1002/9781444304077.ch17

Dolomites: A Volume in Honour of Dolomieu

Dolomites: A Volume in Honour of Dolomieu

How to Cite

Negra, M. H., Purser, B. H. and M'Rabet, A. (1994) Permeability and Porosity Evolution in Dolomitized Upper Cretaceous Pelagic Limestones of Central Tunisia, in Dolomites: A Volume in Honour of Dolomieu (eds B. Purser, M. Tucker and D. Zenger), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304077.ch17

Author Information

  1. 1

    Faculté des Sciences de Tunis, Département de Géologie, Laboratoire de Sédimentologie et Bassins Sédimentaires, 1020-Tunis, Tunisia

  2. 2

    Faculté des Sciences, Université de Paris Sud, Laboratoire de Pétrologie Sédimentaire et Paléontologie, 91405 Orsay, France

  3. 3

    ETAP, 27 bis, avenue Khéreddine Pacha, 1002 Tunis, Tunisia

Publication History

  1. Published Online: 14 APR 2009
  2. Published Print: 25 MAY 1994

ISBN Information

Print ISBN: 9780632037872

Online ISBN: 9781444304077

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Keywords:

  • permeability and porosity evolution in dolomitized Upper Cretaceous pelagic limestones of Central Tunisia;
  • Upper Senonian chalky limestones - providing potential reservoir rocks in oilfields;
  • sedimentological properties of Abiod formation;
  • porosity in cretaceous pelagic dolomites;
  • dissolution of dolomites (dedolomitization);
  • dolomitization - local and genetically related to channels;
  • petrophysical attributes of dolomite;
  • Campanian-Maastrichtian dolomite bodies at Wadi Abiod, Central Tunisia

Summary

Campanian–Maastrichtian sedimentation in Tunisia is dominated by well-bedded micritic limestones rich in planktonic foraminifera. However, in Central Tunisia, notably in Wadi Abiod, lensoid bodies of massively bedded carbonates are frequently intercalated within the chalky pelagic lime mudstones. These lenses, whose properties are both sedimentary and diagenetic, correspond mainly to conglomeratic and bioclastic bodies related to gravity flows. They are affected by dolomitization, which modified several original textures. In terms of reservoir properties, this dolomitization can be destructive or constructive. The pelagic lime mudstones have median porosities and permeabilities which are markedly lower than those of the dolomites that have replaced them locally. Although the lower porosities in the non-dolomitized micrites could result from differential compaction, the absence of visible burial compaction fabrics suggests that the more elevated porosities in the dolomites are the consequence of dolomitization. The amelioration of permeability (0.2–300 mD) is probably the direct result of an increase in crystal size, from an average of 2 µm in the micrite to more than 150 µm in the dolomite, and, as such, is the consequence of dolomitization.