Space-Time Adaptive Methods for Subsurface Flow Simulations – STEERS

Developing and improving CO2 capture and storage (CCS) technologies are essential steps for meeting the global net zero emissions expected by 2050 (Paris agreement, adopted in 2015). The efficiency and safety of such new technologies could be hindered by the presence of fractures. Fracture are among of the primary risk of CO2 leakage. Their structures and connections play a critical role in the dynamics of governing subsurface processes. Numerical simulation is a key tool in order to perform physical process forecasting and risk assessment studies of these new technologies. Building trustworthy predictions require models that accurately describe the subsurface and the various processes over large space time scales.
Such simulations are not easily tractable as their computational cost would be prohibitive with classical numerical methods based on quasi uniform meshes and uniform time steps. Therefore, we propose a novel approach based on space time adaptive numerical methods. For a given level of accuracy, STEERS will reduce the computational cost thanks to three main ingredients: 1/ a combined Hybrid High-Order / Discontinuous Galerkin (HHO/DG) method for the spatial discretization on agglomerated meshes; 2/ a posteriori error estimates steered space time mesh adaptivity algorithms; 3/ an implementation of the proposed space time algorithms in an open source parallel library. This library will be validated throughout the project on applications of increasing complexity: from linear problems (Darcy type) to non linear ones (multiphase flow), from small scale problem to large scale ones (up to thousands of fractures).