Mineralogy, texture and porosity of Callovo-Oxfordian argillites of the Meuse/Haute-Marne region (eastern Paris Basin) - Université de Lorraine Access content directly
Journal Articles Mém. Soc. Géol. France Year : 2007

Mineralogy, texture and porosity of Callovo-Oxfordian argillites of the Meuse/Haute-Marne region (eastern Paris Basin)

Yves Géraud
Béatrice Yven
  • Function : Author
Stéphane Sammartino
  • Function : Author
Françoise Homand
  • Function : Author
  • PersonId : 837594

Abstract

The texture and porosity of Callovo-Oxfordian argillites, coming from the Meuse/Haute-Marne region, have been studied at different scales using borehole and laboratory measurements to more spot-like qualitative and quantita- tive analyses and descriptions of minerals and of the porous space. Due to their limitations and to their resolution, each of the experimental methods used explores differently and often complementarily the porous environment of argillites. The texture is characterised by two-dimensional imaging techniques (optical microscopy, scanning electron microscopy and autoradiography) that provide a view of the material from 0.1 micrometres to a few millimetres or even centimetres. Since borehole measurements are more integrative and representative of the rock in its natural state, they were used to analyse the spatial variability of the porosity. The measurements taken on laboratory samples served to characterise more finely the porous network by providing relevant geometric parameters in order to improve the understanding of the transfer and reaction processes occurring at the interface between fluids and minerals. In the end, a conceptual model for the spatial organisation of the porosity and of the minerals was developed for argillites on the basis of the overall in- formation collected at each step. The reference values for the connected porosity of argillites are obtained by combining the mercury porosity and the calculated porosity in the domain still free from mercury as determined by gas-adsorption techniques. The total connected porosity then varies between 14% for carbonated levels and 19.5% for more argilla- ceous levels. Those values match those measured in boreholes. In percentage of the total porosity, the macroporosity characterised by mercury porosimetry ranges from 20 to 40%, whereas the mesoporosity resulting from the coupling of mercury porosimetry with nitrogen adsorption oscillates between 60 and 80%. The microporosity determined by nitro- gen adsorption is lower than 2%. The relationship between the structure of the porosity and the mineralogy is described by considering 1) the prevailing calcic pole in the upper part of the series around the facies containing argilla- ceous-limestone beds (lithofacies C2d and C2c, and base of C2b) and 2) the argillaceous pole (lithofacies C2b and C2a). The properties of the porous network are discussed afterwards by reviewing water-saturation effects.
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Dates and versions

hal-03698812 , version 1 (19-06-2022)

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  • HAL Id : hal-03698812 , version 1

Cite

Yves Géraud, Béatrice Yven, Stéphane Sammartino, Françoise Homand, Frédéric Villiéras. Mineralogy, texture and porosity of Callovo-Oxfordian argillites of the Meuse/Haute-Marne region (eastern Paris Basin). Mém. Soc. Géol. France, 2007, 178, pp.73-90. ⟨hal-03698812⟩
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