Volume geomechanical restoration: Influence of boundary conditions and rheology.

Pauline Durand-Riard and Marcelle Rodrigues and Guillaume Caumon and Marc-Olivier Titeux. ( 2010 )
in: Proc. 30th Gocad Meeting, Nancy

Abstract

Geomechanical volume balanced restoration allows to take into account, under an elastic behavior law assumption, different geomechanical properties and behavior laws, such as isotropic or transverse isotropic. Unlike kinematic approaches, geomechanical 3D restoration provides an insight to deformation that occured inside layers. However, the restoration workflow is somehow complex, and various parameters may affect the obtained results. Indeed, to apply restoration, one first builds a consistent boundary representation with an adapted mesh resolution, then fills it with adequate geomechanical properties under a specific behavior law. A set of boundary conditions constrain both displacements and contacts. Geomechanical properties, constitutive laws and boundary conditions directly affect the restoration outputs such as the geometry of the restored model, and the restoration properties: dilation and strain tensor. Typically, these results may be used: for structural interpretation (in)validation from strain distribution and geometry, for fracture simulation from derived stress field, or for basin analysis from the burial history. In this paper, we propose to study what influence boundary conditions and rheologies have on restoration results, performing sensitivity studies. This highlight that parameters such as boundary conditions and Poisson’s ratio affect the restored model geometry and the principal directions of the deformation tensor. Moreover, the behavior law has a high impact on the deformation style: an isotropic material reproduces bending; a transverse isotropic rheology is an approach of flexural slip behavior when set along the stratigraphy, and reproduces shear when vertical. Depending on which goals are aimed by applying restoration, one can choose restoration parameters with more confidence knowing how it will impact the results. In addition, based on the regional geological context, using cross-sections and map restorations to constrain kinematics, behavior laws and boundary conditions can be defined in agreement with the geological context. An application to a case-study located in the deep water offshore West Africa illustrates the significance of adequate input parameters.

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BibTeX Reference

@INPROCEEDINGS{DurandRiardGM2010,
    author = { Durand-Riard, Pauline and Rodrigues, Marcelle and Caumon, Guillaume and Titeux, Marc-Olivier },
     title = { Volume geomechanical restoration: Influence of boundary conditions and rheology. },
 booktitle = { Proc. 30th Gocad Meeting, Nancy },
      year = { 2010 },
  abstract = { Geomechanical volume balanced restoration allows to take into account, under an elastic behavior law assumption, different geomechanical properties and behavior laws, such as isotropic or transverse isotropic. Unlike kinematic approaches, geomechanical 3D restoration provides an insight to deformation that occured inside layers. However, the restoration workflow is somehow complex, and various parameters may affect the obtained results. Indeed, to apply restoration, one first builds a consistent boundary representation with an adapted mesh resolution, then fills it with adequate geomechanical properties under a specific behavior law. A set of boundary conditions constrain both displacements and contacts. Geomechanical properties, constitutive laws and boundary conditions directly affect the restoration outputs such as the geometry of the restored model, and the restoration properties: dilation and strain tensor. Typically, these results may be used:
for structural interpretation (in)validation from strain distribution and geometry,
for fracture simulation from derived stress field, or
for basin analysis from the burial history.
In this paper, we propose to study what influence boundary conditions and rheologies have on restoration results, performing sensitivity studies. This highlight that parameters such as boundary conditions and Poisson’s ratio affect the restored model geometry and the principal directions of the deformation tensor. Moreover, the behavior law has a high impact on the deformation style: an isotropic material reproduces bending; a transverse isotropic rheology is an approach of flexural slip behavior when set along the stratigraphy, and reproduces shear when vertical.
Depending on which goals are aimed by applying restoration, one can choose restoration parameters with more confidence knowing how it will impact the results. In addition, based on the regional geological context, using cross-sections and map restorations to constrain kinematics, behavior laws and boundary conditions can be defined in agreement with the geological context.
An application to a case-study located in the deep water offshore West Africa illustrates the significance of adequate input parameters. }
}