Polymer flooding is one of the most widely used enhanced oil recovery methods due to its good performance in numerous large commercial field projects and its relative simplicity and low cost compared to most other enhance oil recovery methods. The main mechanism is considered to be improved sweep efficiency, but numerous studies have also reported lower residual oil saturation to polymer than to water. Because the results depend on many variables such as the initial oil saturation, rock characteristics and polymer characteristics, such experiments must be performed at reservoir conditions and at controlled capillary numbers and so forth to measure the reduction that applies to field polymer floods. Furthermore, a mechanistic model is needed to scale up the laboratory coreflood results to the field.
We implemented and tested the new model for the residual oil saturation in a mechanistic numerical reservoir simulator. The simulation model was used to match the oil recovery and pressure drop of both secondary and tertiary polymer flood experiments. The results showed a strong correlation between the remaining oil saturation and the Deborah number.