Comparative analysis of carbon dioxide, methane, and hydrogen plume migration in aquifers

The use of geological reservoirs in support of a sustainable energy system has been explored for decades. Geological carbon storage (GCS), underground gas storage (UGS), and underground hydrogen storage (UHS) are prominent examples of such applications. Among the available geological settings, saline aquifers represent a feasible large-scale option for subsurface storage.

To reliably assess reservoir performance and conduct sensitivity analyses, physics-based simulation toolboxes with accurate thermophysical and petrophysical descriptions (density, viscosity, solubility, relative permeability, etc) are essential, in addition to field and laboratory studies. DARSim (Delft Advanced Reservoir Simulator) is an open-source, MATLAB-based simulator capable of fully compositional flow modeling. Combined with the algebraic dynamic multilevel (ADM), it provides an effective framework for multiscale reservoir simulations.

This work begins with a comparative analysis of CO₂, CH₄, and H₂ flow in brine-saturated porous media to examine how differences in gas properties influence reservoir-scale flow behavior, and trapping mechanisms. The study first reproduces the FluidFlower benchmark, a numerical–experimental study originally developed for CO₂, for all three gases. Subsequently, an upscaled version of the benchmark is investigated to evaluate model performance using a multiscale strategy. The adaptive multilevel method (ADM) efficiently captures key subsurface processes, including buoyancy-driven migration and phase partitioning. By dynamically refining regions with strong gas mass fraction gradients and coarsening smoother areas, ADM balances computational efficiency with the accuracy required to represent essential flow and transport behavior in heterogeneous reservoirs.