Hybrid Multiscale Modeling through Direct Substitution of Pore-Scale Models into Near-Well Reservoir Simulators

A hybrid, multiscale reservoir simulator has been developed that directly substitutes pore-scale models for continuum-scale, finite-difference grids. Over 7500 pore scale models (∼75 million pores) are inserted into a ∼1 m2 pore-scale region around a producing well, which is coupled to an outer, fine-scale finite-difference model with 10 000 cell-centered grids. This computationally demanding problem is possible because the domain is decomposed into manageable subdomains (thousands of pore-scale models and one continuum region) and then coupled together using finite-element mortars to ensure continuity between the subdomains. Here, flow is single-phase, single-component, and steady-state, but the potential of the simulator for more complex, near-well flows is demonstrated. A priori, direct upscaling and a posteriori, global upscaling are both performed, and it is shown that the direct approach results in significant inaccuracies in the pressure and flow fields but the global upscaling approach results in ...