Deriving a restoration workflow to compute paleo stress.

@inproceedings{RUDKIEWICZ_RM2021,
 abstract = { Since several years, a restoration workflow called Kine3D3 exists inside the commercial skua software. Restoration aims at reconstructing past geometry and derive deformation parameter between successive geometries. This paper will illustrate how the restoration workflow has been derived to approach paleo stress on complex geological cases. This allows to take full advantage on one hand, of the capacity of the mechanical solver usually dedicated to restoration, and on the other hand, of the detailed geological configurations that water tight geometric descriptions are providing. Estimating stress in the past first requires past geometry. Geometry in the past is achieved through the now classical restoration and removal of younger stratigraphic units. Then, stress is estimated through the computation of equilibrium of forces in response to external constraints and internal forces. Based upon two examples, one in extensional setting, the other with a complicated salt dome, we will discuss the type of external and internal constraints that can be set and how they influence the stress distribution. Usually, modeled volumes are just parts from large scale geodynamical units. In the modeled volume, stress results from large scale deformations that need to be defined with adequate boundary conditions on the lateral borders of the volume. The simplest external constraints can be constant displacements perpendicular to lateral borders, either resulting in compression or extension. But displacements with an angle to the lateral borders can also be handled. Furthermore, when modeling volumes are not oriented along the axes of far field strains, we will show how to define spatially variable lateral boundary conditions. But constraints might also be displacements on the bottom boundaries, thus mimicking large scale plate deformations. When computing stress, faults also play an important role in the transmission of forces. When handling faults as twin surfaces with friction, the friction parameter is, as expected, a major internal parameter that will be investigated on one of our example. Next to external boundary conditions, one other major internal parameter in mechanical rock deformation is the rock rheology. In order to have fast computations, isotropic elastic rock behavior is today the preferred standard rheology. We will show some tests made to use different rheology and discuss their relevance. },
 author = { Rudkiewicz, Jean-Luc AND Astart, Laurent AND Amauger, Valentin },
 booktitle = { 2021 RING Meeting },
 publisher = { ASGA },
 title = { Deriving a restoration workflow to compute paleo stress. },
 year = { 2021 }
}