Upscaling of Geocellular Models for Flow Simulation

Geocellular reservoir descriptions are generally much too detailed for direct use in reservoir flow simulations. Upscaling procedures are required to coarsen these detailed reservoir models to scales more suitable for flow calculations. In this talk, a number of different upscaling techniques, appropriate for both moderate and high degrees of coarsening, will be described and illustrated. Upscaling of single-phase parameters (permeability) will be considered first. The approaches discussed include upscaling and grid generation techniques for unstructured models, upscaling in the near-well region, and an efficient local-global procedure for the calculation of upscaled transmissibilities that depend on the global flow field. The high level of accuracy of these methods will be illustrated for different types of permeability characterizations and global flows.