A simulation workflow for large-scale CO₂ storage in the Norwegian North Sea

Large-scale CO₂ injection problems have revived the interest in simple models, like percolation and vertically-averaged models, for simulating fluid flow in reservoirs and aquifers. A series of such models have been collected and implemented together with standard reservoir simulation capabilities in a high-level scripting language as part of the open-source MATLAB Reservoir Simulation Toolbox (MRST) to give a set of simulation methods of increasing computational complexity. Herein, we outline the methods and discuss how they can be combined to create a flexible tool-chain for investigating CO₂ storage on a scale that would have significant impact on European CO₂ emissions. In particular, we discuss geometrical methods for identifying structural traps, percolation-type methods for identifying potential spill paths, and vertical-equilibrium methods that can efficiently simulate structural, residual, and solubility trapping in a thousand-year perspective. The utility of the overall workflow is demonstrated using real-life depth and thickness maps of two geological formations from the recent CO₂ Storage Atlas of the Norwegian North Sea.