Reservoir modeling becomes more difficult as reservoirs become more complex. To get an acceptable description of a reservoir, many simulations need to be carried out in different regions of the search space. These simulations should not be limited to a few "most plausible" parameter sets. Due to lack of time and increasing pressure to produce results, the studies carried out often remain incomplete. In this work, a methodology is proposed that tries to involve a broader search space than usual and identifies different starting points in a multidimensional search spatial, with a high potential to generate production profiles that match the measured data. The case study is Chachahuén Sur, a large-scale field located on the Neuquén basin which is under incipient secondary recovery. The development of the field began in 2013, after the exploratory and extension drilling campaign targeted at Rayoso Formation, a succession of early Cretaceous fluvial cycles. These cycles are truncated by the Intersenonian unconformity, which lies between the reservoirs of the Rayoso Formation and the shaly base of the Neuquén Group and works as a regional seal. The main production cycles correspond to cycles 2a, 3a and 1c. In the present, 395 wells have been drilled. 76 of them are injectors wellbores and 47 more are expected to be converted. Towards the end of 2022, a polymer injection project is planned for the sandstone of cycle 2a using 50 injection wells, 41 of which are currently water injectors.