AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Basin Modeling in Complex Setting: New Developments and Workflows
(1) Beicip-Franlab, Rueil-Malmaison, France.
(2) IFP Energies Nouvelles, Rueil-Malmaison, France.
Accounting for faults as a key controlling factor on fluid flows through time and on structural evolution is of primary importance for 2D or 3D basin modeling in moderately to highly faulted environments. The joint modeling of 3D deformation and fault properties allows enhancing the petroleum system evaluation in complex environments, from fold and thrust belts to extensive settings.
Recent developments in 3D restoration tools coupled to geomodels (Kine3D - Gocad/Skua), and based on mechanically calculated deformation, allows for (1) the construction of a 3D volumetric mesh describing accurately the geometry and (2) its step by step restoration through time. It enables to compute a continuous deformation of this mesh through time. Geological time is discretized in steps (or "events"), and we assume a linear deformation pathway during these events. The limitations attached to classical basin model meshes are overcome: the deformation accounts effectively for the lateral component of the deformation, the layers are not necessarily laterally continuous and it supports non matching cells on each side of the faults.
The IFP’s new generation basin simulator, Arctem, is developed with the objective of using such unstructured meshes continuously deformed through time in a forward simulation coupling kinematics, stress and fluid flow. Arctem’s main added value relies on its ability to (1) handle unstructured meshes made of hexahedron or tetrahedron cells, and (2) model fluid flow along & across fault. A particular attention has been paid to the definition and characterization of faults through time. Faults are simply handled as internal boundaries in the mesh and do not need to extend to the borders of the domain or another fault. This adds flexibility in the workflow since it is not necessary to design multiple blocks in the model. Faults hydraulic properties can change through time and impact fluids flow along and across them.
This integrated workflow has proven to be operational, flexible and efficient when applied to real cases because the processing tasks, required to generate a mesh evolving through time and computable by a basin simulator, have been significantly reduced. It has been applied successfully so far in various environments, from extensive settings in the North Sea to compressive areas. The added value of accounting accurately for the kinematics and the faults hydraulic properties through time will be exemplified in the presented case studies.