Current bottlenecks in geomodeling workflows and ways forward

After more than 20 years of progress, reservoir modeling still raises practical and theoretical challenges. Standard workflows are primarily built in a linear fashion (fault framework modeling, stratigraphic modeling, gridding, petrophysical modeling, upscaling, flow simulation and history matching). Modifying decisions taken at an early step of this workflow requires going through all the dependent steps and the associated quality controls once more. Whereas robustness has significantly improved and now makes it possible to improve automation and running of multiple scenarios, we identify four main limitations in the current workflows and propose possible strategies to address these limitations. First, we suggest ways to effectively sample uncertainty about well correlations by using sedimentological concepts and propagate it in existing time-to-depth conversion and gridding workflows. Then, we propose to analyze fault displacement when deciding about fault connectivity rather than discovering fault displacement in the last stage of structural framework building. Gridding should then ideally account for static data (geological structures, facies and associated permeability fields) and dynamic data (boundary conditions) while honouring discretization constraints. Although stair-step grids are a significant improvement to better handle some of these constraints, recent developments in unstructured gridding open new perspectives to address gridding challenges with more flexibility. Last, we advocate that multiple scales should be considered before the reservoir grid is created, and that connectivity and topological considerations should be used to ensure internal consistency between scales, once models have been constrained by first-order dynamic information.