LOCAL-GLOBAL TWO-PHASE UPSCALING OF FLOW AND TRANSPORT IN HETEROGENEOUS FORMATIONS

Flow and transport in subsurface formations are affected by geological variability over multiple length scales. In this work, we develop a local-global two-phase upscaling approach to generate upscaled transport functions. The upscaling of multiphase flow parameters is challenging, due to their strong dependency on global flow effects. The local-global two-phase upscaling directly incorporates global coarse-scale two-phase solutions into local two-phase upscaling calculations. It effectively captures the impact of global flow, while avoiding global two-phase fine-scale simulations. The local boundary conditions are updated with time-dependent coarse-scale solutions. It therefore captures the global flow effects both spatially and temporally. The method is applied to permeability distributions with various correlation lengths and for different fluid-mobility ratios. Numerical results show that it consistently improves upon existing two-phase upscaling methods (e.g., upscaling with effective flux boundary conditions) and provides accurate coarse-scale solutions for both flow and transport.