The petroleum industry has shown increasing interest over the last decade in chemically enhancing the oil recovery in mature fields, especially polymer and alkali-surfactant-polymer injection projects. In Austria, OMV Upstream is injecting polymers into the 8 Torton Horizon and 9 Torton Horizon. Furthermore, an alkali-polymer injection project is planned for the 16 Torton Horizon (TH). These reservoirs consist of heterogeneous sandstones with different rock types, having a different impact on the polymer project intended. Polymer injection has been one of the most used Enhanced Oil Recovery (EOR) methods implemented worldwide, due to its simplicity and efficiency. Several studies regarding the physical properties of the polymer, such as polymer adsorption, Residual Resistance Factor (RRF), and Inaccessible Pore Volume (IPV) and their impact on oil recovery, were conducted and reported. Nevertheless, the effect of rock types on polymer behavior and incremental oil recovery was not covered; therefore, a simulation model was set to investigate the impact of having different polymer properties per rock types. A 2D reservoir model of the 16 TH was used to examine the impact of rock types on polymer behavior and incremental oil production under uncertainty conditions. The variables used in the investigation are RRF, IPV, and polymer adsorption, where the Latin hypercube sampling model generated different variable points within a fixed variance. Having different polymer physical properties depending on the rock type is shown to impact the polymer performance, and therefore incremental oil production. The recovery factor increased from 42.5% to almost 50% of IOIP in the numerical model based on 16 TH properties by merely understanding the influence of each rock type on the polymer properties. Hence, understanding the effect of having different rock types on polymer behavior would prevent overestimating or underestimating the amount of oil that will be recovered by injecting polymer. This can be achieved by either increasing the previous laboratory work to reduce the uncertainty or by incorporating the full range of uncertainty, as shown in this work in reservoir simulation of all-polymer pilot evaluations.