Polymer flooding is one of the methods of chemical enhance oil recovery. In fact, polymer flooding is one of both mobility control methods and chemical methods, and this method improves both microscopic and macroscopic efficiencies of oil production. The polymers used to enhance oil recovery are generally based on acrylamide, which is a synthetic, water-soluble polymer This polymer has been highly regarded due to its reasonable price, solubility in water under various conditions and its ability to be produced non-ionically, anionically and cationically, as well as the ability to achieve high and different molecular weights in enhance oil recovery. In this study, in order to investigate the optimum amount and the minimum of injection polymer and the colapsing concentration of the micromodel and also to observe the phenomenon of fingering we use anionic polyacrylamide polymers with a water content of about 25% molar with a molecular weight of about 18 million, which has been proven to increase its yield. Understanding the fluid movement in porous media helps to find the most effective EOR methods. In order to investigate the effect of polymer injection and find the optimal concentration for heavy oils, we have used glass micromodels that are very close to the dimensions of the porous media. The polymer used in this research is hydrolyzed polyacrylamide which is injected in micromodel in 5 concentrations of 500, 1000, 1500, 2000 and 4000 on three types of heavy oils with viscosities of 190 cp, 230 cp and 290 cp. At each stage, the amount of oil recovery with injected polymer was evaluated by high quality cameras using image processing. At 190 cp the recovery was between 52.45 to 62.89 percent. At 230 cp the recovery was between from 50.19 percent to 65 percent and at 290 cp the recovery was between from 38.64 percent to 74.58 percent The presence of the s-shaped region as well as the minimum and optimal amount of recovery for EOR was proved and also the colapsing concentration of the micromodel was found to be about 4000 ppm. Keywords: Micromodels, polymer flooding, optimum concentration, enhance oil recovery, heavy oil
