Integrated waterflood asset management consists of reservoir simulation and characterization, fluids and their behavior in the reservoir, creation and operation of wells, and surface processing of the fluids. In this article, waterflooding project is evaluated in the Field K located in the southeastern part of Turkey. The field was discovered in 1961 and has been on production since then. There are a total of 29 wells with 10 producers, 9 closed-in, 3 dumpflooders, 4 injection wells, and 3 abandoned wells in Field K. After obtaining all production, injection and pressure data and making necessary interpretations, water injection performance analysis were carried out. Performance prediction of oil production with well configurations was done. Determination of the location of new wells is a complex problem that depends on reservoir and fluid properties, well and surface specifications, and economic criteria. The operating strategy for this project is based upon a reservoir simulation study as numerical models are detailed and powerful predicitive tools in reservoir management. To reach this goal, a commercial simulator software (IMEX) that is the Computer Modelling Group's (CMG) new generation adaptive simulator was used. One objective of this study was to obtain history matching of 41-year-old robust reservoir with simulation model. The simulation program (IMEX) was able to history match for all of the parameters which resulted on satisfactory history match. Five scenarios were applied in this study to observe the effect of well configurations. These scenarios were performed as drilling of new vertical wells, converting of existing vertical wells to horizontal wells and converting some of the existing wells into water injectors. Using horizontal producers is the most efficient methods in all of the other scenarios. 5,114,000 bbls (20%) of additional oil recovery was achieved if horizontal producers were used.