For very viscous oils(>500cp),a stable polymer flood is not economical due to low processing rates.In suchcases,a partially stable(mobility ratio >1)polymer flood must be designed.Depending on the magnitudeof viscosity ratio,these displacements will be influenced by viscous fingering.Typically,viscous fingerscannot be accurately captured with the grid sizes used in full-field simulations.To optimize and design apartially-stable polymer or water flood,it is critical to correctly upscale the laboratory-generated relativepermeability curves for reservoir simulation.In recent years,such models have been published in SPEliterature.Unfortunately,most of these models require multiple fitting parameters(3+).In this work,wepresent a simplified technique that requires systematic change in only one parameter to generate upscaledrelative permeability curve for a given viscosity ratio.Using fine-grid simulations,we show that due to small-scale random heterogeneities,the flow at highviscosity ratio is channelized even in a core perceived to be homogeneous at laboratory scale.Upscalingaverages these fine variations in heterogeneities,causing the grids to be over-swept,and thus the recoveryis over-predicted.To compensate for this over-prediction,relative permeability curves need to be upscaled.
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