3D Sequential Structural Restoration: Geometry and Kinematics

Pierre Muron¹, Jean-Laurent Mallet¹, and Donald A. Medwedeff^2
1 École Nationale Supérieure de Géologie, INPL/CRPG, Nancy, France
² Basin Analysis Team, ChevronTexaco Energy Technology Company, San Ramon, CA

Structural restoration brings important insights into the behavior and evolution of geologic structures through time, playing a key role in characterization, validation and improvement of three-dimensional models.

We introduce a new parametric approach for truly three-dimensional sequential restoration where kinematics is guided by user-defined boundary conditions and deformation style. The methodology is based on a hybrid algorithm mixing both geometrical and geo-mechanical principles.

Complex geological structures are modeled with a set of triangulated surfaces, which represent horizons, faults and model boundaries that delimit tetrahedral sedimentary layers. Constraints are applied to mesh displacements to ensure geological consistency and impose a user-defined restoration kinematics. For this purpose, volume conservation and strain minimization are weighted according to a deformation model defined by (1) spatial contrasts in rock mechanical properties and (2) a deformation style (isotropic deformation, constant or variable inclined shear, or flexural slip).

Analysis of the three-dimensional geometry of sedimentary layers and its evolution through time are made possible by sequential restoration. Three-dimensional strain tensors can be derived for each time step. We show how appropriate visualization techniques for both three-dimensional restored geometry and strain field bring new perspectives for structural interpretation and may help discriminate between several geological hypotheses in a fold-and-thrust belt context.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005