Cañadón León is a mature oil field located on the southern flank of the San Jorge Gulf Basin with over 70 years of production history. The field is currently experiencing low waterflooding recovery efficiency due to an unfavorable mobility ratio. These conditions make a great opportunity for an enhanced oil recovery by polymer injection. The area of interest was selected from a regional geological interpretation, where12 stratigraphic cycles were evaluated, with their respective volumetric estimates, petrophysical properties evaluation and connectivity prognosis. In addition, average temperatures and permeabilities, and current recovery factors, were verified to identify the size of the opportunity. The study was based on multiple iterations of static models and numerical simulation integrating 3D seismic, well logs, core data, formation pressures, and production history per stratigraphic cycle. A wide variety of equiprobable models were generated. These models supported the history matching and their respective forecasts, resulting on p10-p50-p90 scenarios. The main difference remains on the distribution of recoverable mobile oil and fractional flow, confirming that polymer injection is the most appropriate technique for revitalizing the area. The initial production must be synchronized with the injection, and it is highly recommended not to start producing wells before injection starts as it could decrease the recovery factor in the short term, deteriorating the sweep efficiency. As a result of the study, the reservoirs with the best petrophysical properties, high remaining oil saturation, and fine lateral connectivity were determined. The identified opportunity triggered the generation of a polymer injection project involving the drilling of 12 wells (6 producers and 6 injectors) and 6 workovers. The associated activity for this polymer flooding project is currently on course. The aim of this pilot is to verify the technical feasibility of polymer injection as a method to increase the recovery factor in a short period of time and to acquire sufficient information to expand this development strategy in the field.