Paramétrisation géo-chronologique

Rémi Moyen. ( 2005 )
INPL, Nancy, France

Abstract

3D parameterisation of the geological space in sedimentary geology : the GeoChron model Reservoir modelling requires building a volumic mesh usually adapted to faults and horizons of the domain, on which petrophysical property models are computed. The common practice consists in using stratigraphic curvilinear grids formed of hexahedral cells whose indexes (i, j, k) constitute a sampling of a 3D parametric function (u, v, t) where (u, v) correspond to the “paleo-geographic” coordinates tangent to the horizons and (t), viewed as an analog to the geological age of the terrains, is approximately orthogonal to the horizons. These grids are suited to the property-modelling geostatistical algorithms but their topological regularity induces errors or approximations in complex fault networks or folded environments. The GeoChron model corrects these drawbacks by clearly segragating the geometry of the domain of study (modelled by an unstructured tetrahedralised mesh), the link between this geometry and the geometry of the layers at the time of deposition (thanks to a 3D parametric function (u, v, t)) and the property model (computed in a regular fine-scaled grid). After exposing the mathematical framework of this model which emphasises the similarity with time stratigraphic (or Wheeler) diagrams used in sedimentology, we show two practical ways of building such a parameterisation and their implementation in the g cad geomodelling software. Then we show how the (t) component of the parametric function can be used to automatically compute a geometric estimate of the throw vector in any point of a fault surface. Finally, we present some applications concerning petrophysical property modelling, deformation estimation or seismic data integration.

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BibTeX Reference

@PHDTHESIS{Moyen05,
    author = { Moyen, Rémi },
     title = { Paramétrisation géo-chronologique },
   chapter = { 0 },
      year = { 2005 },
    school = { INPL, Nancy, France },
  abstract = { 3D parameterisation of the geological space in sedimentary geology :
the GeoChron model
Reservoir modelling requires building a volumic mesh usually adapted to faults and horizons of the
domain, on which petrophysical property models are computed. The common practice consists in using
stratigraphic curvilinear grids formed of hexahedral cells whose indexes (i, j, k) constitute a sampling of a
3D parametric function (u, v, t) where (u, v) correspond to the “paleo-geographic” coordinates tangent to
the horizons and (t), viewed as an analog to the geological age of the terrains, is approximately orthogonal
to the horizons.
These grids are suited to the property-modelling geostatistical algorithms but their topological regularity
induces errors or approximations in complex fault networks or folded environments. The GeoChron
model corrects these drawbacks by clearly segragating the geometry of the domain of study (modelled by
an unstructured tetrahedralised mesh), the link between this geometry and the geometry of the layers at
the time of deposition (thanks to a 3D parametric function (u, v, t)) and the property model (computed
in a regular fine-scaled grid).
After exposing the mathematical framework of this model which emphasises the similarity with time
stratigraphic (or Wheeler) diagrams used in sedimentology, we show two practical ways of building such
a parameterisation and their implementation in the g
cad geomodelling software. Then we show how
the (t) component of the parametric function can be used to automatically compute a geometric estimate
of the throw vector in any point of a fault surface. Finally, we present some applications concerning
petrophysical property modelling, deformation estimation or seismic data integration. }
}