3D Inverse and Direct Structural modeling Workflow

17/2009

3D Inverse and Direct Structural modeling Workflow

Thursday 18th June 2009

Longoni, Matteo; Magistroni, Corrado; Ruffo, Paolo; Scrofani, Giovanni

The description and the interpretation of the geological evolution of sedimentary basins has recently received a great support from the use of mathematical models and numerical methods, taking advantage of more advanced hardware, both in graphic and computing power. We have developed a geological modeling workflow, based on gOcad, for the 3D inverse and direct structural modeling of sedimentary basins. The workflow is based on an appropriate number of time-steps of restoration modeling coupled with forward/evolution modeling. During each step a gOcad geological model provides support for data managing, pre- and post-processing for numerical solvers and the necessary interpretative model editing. The capability of capturing and describing all the geometrical and structural features of an accurate geological model, leads to remarkable results in integrating available data, in validating restoration models and in reconstructing a reliable evolution of a basin. The model is built with gOcad, starting from the basin geometrical data. Topological complexities such as faulted stratified layers and salt diapirs are easily handled in a three-dimensional unstructured framework. Then the geometrical model is enriched with its physical properties, coming from seismic, well and field data and from the modeller conceptual model. The domain is then described with a user-defined tetrahedral mesh, necessary for the numerical simulation of its geological evolution. The output results, for example the updated position of horizon and fault surfaces, and the distributions in the domain of physical quantities such as stresses and displacements, are then imported in gOcad by means of a fully-automatic procedure, for data visualization and analysis. The workflow can be iterated starting from the last updated configuration. We present the application of the workflow to the simulation of the dynamic structural evolution in two realistic cases: a multi-faulted system and a diapir growth in a multi-layered sedimentary basin.