Restauration et incertitudes structurales : changement d'échelles des propriétés mécaniques et gestion de la tectonique salifère

Institut National Polytechnique de Lorraine

Abstract

Structural restoration of geological models is undertaken to evaluate the geometrical and geological coherency of an interpretation. It can be used to determine deformation rates in different tectonic regimes. In addition, this technique has been used to evaluate high strain zones, and thus, potential fractured zones. Structural restoration attempts to reverse the effects of deformation history to an assumed initial pre-deformation state. Volumetric restoration techniques generally employ entirely continuum mechanic methods. The continuum mechanic model behaviors are dependent on the definition of the materials for which it is imposed reversibility by using elasticity behavior laws. This property is chosen based upon the predominant rock type in the fault block, generally at small scales. To overcome this issue, a methodology to upscale elastic isotropic materials has been implemented by treating upscaled materials as elastic transversely isotropic materials. This insures energy conservation for the same types of loading. Another focus of this work has been the management of salt tectonics in restoration procedures. A multi-surfaces restoration methodology has been developped based on the conservation of apparent thicknesses between stratigraphic layers and an iso-parametric restoration. This technique avoids the dependence of the volumetric restoration on a material model, while properly treating the restoration of unconformities and halokinetic sequences that characterize the flanks of salt structures. This technique has been tested on a field data set over a salt-withdrawal basin in the La Popa Basin (northeastern Mexico).

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BibTeX Reference

@PHDTHESIS{,
    author = { Titeux, Marc-Olivier },
     title = { Restauration et incertitudes structurales : changement d'échelles des propriétés mécaniques et gestion de la tectonique salifère },
      year = { 2009 },
    school = { Institut National Polytechnique de Lorraine },
  abstract = { Structural restoration of geological models is undertaken to evaluate the geometrical and geological coherency of an interpretation. It can be used to determine deformation rates in different tectonic regimes. In addition, this technique has been used to evaluate high strain zones, and thus, potential fractured zones. Structural restoration attempts to reverse the effects of deformation history to an assumed initial pre-deformation state. Volumetric restoration techniques generally employ entirely continuum mechanic methods. The continuum mechanic model behaviors are dependent on the definition of the materials for which it is imposed reversibility by using elasticity behavior laws. This property is chosen based upon the predominant rock type in the fault block, generally at small scales. To overcome this issue, a methodology to upscale elastic isotropic materials has been implemented by treating upscaled materials as elastic transversely isotropic materials. This insures energy conservation for the same types of loading.

Another focus of this work has been the management of salt tectonics in restoration procedures. A multi-surfaces restoration methodology has been developped based on the conservation of apparent thicknesses between stratigraphic layers and an iso-parametric restoration. This technique avoids the dependence of the volumetric restoration on a material model, while properly treating the restoration of unconformities and halokinetic sequences that characterize the flanks of salt structures. This technique has been tested on a field data set over a salt-withdrawal basin in the La Popa Basin (northeastern Mexico). }
}