Quantification of polymer viscoelastic effects on SOR reduction using modified capillary

A method of quantifying a viscoelastic effect of a polymer on residual oil saturation (Sor) including calculating an extensional capillary number (Nce) using flux, pore-scale apparent viscosity, and interfacial tension to account for the polymer's viscoelastic forces that are responsible for Sor reduction. The polymer is used polymer flooding during enhanced oil recovery. An extensional capillary number is calculated for a plurality of polymer materials, which are then compiled in a database. Also provided is a reservoir simulator for predicting the Sor reduction potential of the viscoelastic polymer, which includes a database of calculated extensional capillary numbers for a plurality of polymers. The database includes a curve generated from the calculated extensional capillary numbers for a plurality of polymers properties, flux rates, formation nature, oil viscosities, and rheological behaviors.