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We propose a workflow for updating 3D geological meshed models to test different layering scenarios and to assess their impact on the simulation of CO2 injection. This workflow operates on a tetrahedral mesh that encodes rock unit information as well as rock physical properties. The alternative layering meshes are built by modifying the input mesh and inserting a new horizon defined by a scalar field. Modifying consistently a 3D meshed model while keeping its quality is a challenge that we tackle using the advanced capabilities of MMG, an open source remeshing library. CO2 injection is then simulated with GEOSX, an open-source, multiphysics, and multilevel simulation solver. We demonstrate this workflow for stratigraphic layering uncertainty assessment on a simple synthetic layered reservoir on the flank of a salt diapir. Comparison of simulation results is eased since modifications of the mesh are localized to the area around the inserted horizon. The consistent results highlight the role of stratigraphic unconformities for trap integrity. This work opens a promising path for developing numerical simulation of CO2 injection on unstructured meshes by combining advanced coupled flow-geomechanical models in geological domains affected by structural uncertainties.

Abstract  This paper proposes a novel history-matching method where reservoir structure is inverted from dynamic fluid flow response. The proposed workflow consists of searching for models that match production history from a large set of prior structural model realizations. This prior set represents the reservoir structural uncertainty because of interpretation uncertainty on seismic sections. To make such a search effective, we introduce a parameter space defined with a “similarity distance” for accommodating this large set of realizations. The inverse solutions are found using a stochastic search method. Realistic reservoir examples are presented to prove the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

In Solid Modeling, a boundary representation (b-rep) defines solids by their bounding surfaces, providing an efficient volume description. Building on this representation, we present the notion of a Sealed Geological Model. In such a model, the geological surfaces define a partition of the domain of interest into regions; analytic functions can be defined in these regions to describe the spatial variations of the subsurface properties. Such descriptions can be used in Geophysics, 3D GIS, and for discretization purposes. In addition to the b-rep representational validity conditions, Sealed Geological Models must satisfy conditions of geological consistency. Bearing these conditions in mind, we describe a methodology to create and modify the shape of such sealed models interactively. We use the hierarchical relationship between geological surfaces to help reshape the contact between a fixed surface (a surface that other surfaces can slide along, such as a fault, erosion surface, or salt top) and a secondary deformable surface (e.g. horizon, older fault). Although designed to meet the demanding requirements of interactive model editing, our methodology could also make use of displacement vectors computed by an automatic process such as tomographic inversion or 3D balanced unfolding. [ABSTRACT FROM AUTHOR]