Core-scale simulation of polymer flow through porous media

Abstract

The behavior of partially hydrolyzed polyacrylamide (HPAM) polymer solutions in porous media is more complicated than what the bulk rheology might suggest. In addition, HPAM polymers exposed to high frontal velocities during corefloods display shear thickening and degradation characteristics. Recently developed models have displayed the capacity to accurately predict numerical values for the apparent viscosity behavior of HPAM polymers in the shear thickening and degradation flow regimes without in-depth data from coreflood experiments. The ability to simulate this polymer behavior is valuable when selecting effective polymer flood designs for field applications. This work aimed to determine whether or not a commercially available simulator could accurately simulate single- and two-phase polymer coreflood experimental results conducted for a range of injection rates. The adherence to physically realistic input values with respect to experimentally derived parameters was of primary importance during the development of the models. In the single-phase simulations, the shear thinning, shear thickening, and degradation flow regimes were successfully modeled, but numerical issues arose for the highest injection rates corresponding to the polymer degradation flow regime. Analytical models developed to predict porous medium apparent viscosities were used with appropriate adjustments of the permeability reduction factor RRF to history match core-scale experimental pressure drop data. In the two-phase polymer flood in a water-wet porous medium, the modeled polymer behavior spanned from the shear thinning to the shear thickening flow regimes, but did not include any polymer degradation data. With this model, both the pressures and cumulative oil production were successfully matched. Ultimately, understanding, modeling and predicting the polymer behavior on a core-scale under various flow conditions will improve the ability to design polymer floods on the field scale.