Unraveling chalk microtextural properties from indentation tests

Classifying chalk microtextures: Sedimentary versus diagenetic origin (Cenomanian–Santonian, Paris Basin, France)

“…The approach present here, however, can be applied to the microtextures observed by Faÿ‐Gomord et al . (,b), from six outcrops across Belgium, England and France, with maximum burial depths ranging from 200 to 1800 m. Hjuler & Fabricius () observed similar microtextures in numerous onshore and offshore chalks in the North Sea area; well‐preserved microtextures and porosity were noted in Danish chalk outcrops, due to high pore pressure, and also in chalk from Valhall Field (burial depth of 3 km), with hydrocarbon presence. Similar microtextures with low porosity, well‐developed recrystallization and cementation features have been described in English outcrops, and in the Dan, South Arne and Ekofisk fields (Hjuler & Fabricius, ).…”

“…mainly controls the mineralogical composition of chalk, depending on its spatio‐temporal situation (Fabricius, ). These controls influence microtexture at all levels (Pure versus Impure Chalk Microtexture Group; Siliceous versus Argillaceous Microtexture Subgroup; Dispersed, Unoriented, Oriented or Draped clay microtexture class), thus affecting the petrophysical and mechanical properties of chalk (Hardman, ; Fabricius, ; Fabricius et al ., , ; Strand et al ., ; Faÿ‐Gomord et al ., , ).…”

“…Similar microtextures with low porosity, well‐developed recrystallization and cementation features have been described in English outcrops, and in the Dan, South Arne and Ekofisk fields (Hjuler & Fabricius, ). The main factors controlling petrophysical (for example, porosity, permeability, specific surface area and tortuosity) and geomechanical properties are the type and amount of non‐carbonate minerals and the degree of cementation (Hjuler & Fabricius, ; Faÿ‐Gomord et al ., ,b, ), corresponding respectively to the Impure Chalk Microtexture Group and the Pure Chalk Microtexture Group.…”

“…Duperret et al ., ). Terms for the matrix include microfabric (Duperret et al ., ), nannofacies (Richard et al ., ), microstructure (Aubry, ; Gaviglio et al ., ; Nadah et al ., ; Shitrit et al ., ), texture (Le Roux, ; Kaczmarek et al ., ) and microtexture (Lambert et al ., ; Fabricius et al ., ; Deville de Periere et al ., ; Faÿ‐Gomord et al ., ,b, ). The term adopted for the chalk matrix in this article is microtexture.…”

“…Masson, ; Lafrance et al ., ), geomechanics (e.g. Mortimore & Fielding, ; Faÿ‐Gomord et al ., ) and cliff erosion/alteration (e.g. Duperret et al ., ).…”