Modeling Complex Tectonic Structures in Any Kind of Grid without Space Deformation

Summary In order to achieve an accurate reservoir characterization, geometrical complexities of reservoir geobodies must be taken into account. Hence, restoration of the complex geobodies, impacted by tectonic activities, folding and faulting, is a primary issue in geological modelling of petroleum reservoirs. Facing the geometrical complexities, a common solution is producing curved grids, fitted to folding pattern as it is done in most of the main geological modelling software. It leads to satisfactory geological models, which may be difficult to transfer to the Reservoir Engineer who is often requiring quite regular grids for flow simulations This upscaling results in losing the initial geological resolution and the loss is generally difficult to control. This paper describes an alternative method for generating distorted geobodies following folds and faults inside any kind of grid. It is based on the combination of local geostatistics and a mathematical framework using properties of Stochastic Partial Differential Equations (SPDE). This technique is efficient enough to manage large grids and large datasets. Then we can generate very high resolution geological models with structurally driven properties distribution, which can be upscaled by preserving the geological consistency in reservoir grids of any shape, regular, irregular, Voronoi, or any unstructured grids.