The efficient and effective recovery of hydrocarbons is one of the major challenges for any oil and gas company. This is especially true in countries in which the potential for significant new discoveries of these resources is limited. Optimizing and improving the recovery from brown fields can be achieved in various ways ranging from target-oriented infill drilling (based on new and more detailed information about the subsurface geology) to the implementation of enhanced recovery methods. The main aim of this thesis was to develop an optimized production strategy for the production unit 209-33 in the Matzen oil field. Unit 209-33 is a part of the 9th Tortonian Horizon and located in the geologically complex Matzen fault system. It can be considered as a kind of satellite production unit to the main compartment of the 9th Tortonian layer. Production in this reservoir started in the 1960s. By 2016 a primary recovery factor of approximately 60 % had been reached, which was also reflected by the very high water cut of 95 %. In the same year an already existing production well was relocated from a deeper oil-bearing rock formation to production unit 209-33. Since then the water cut of this new well has remained stable at around 13 %. As this was quite unusual, it was decided to carry out a reassessment of the oil field to achieve a better understanding of the characteristic features. Special emphasis was put on the influence of geological faults. After all, the development of an economically viable production strategy is only possible, if the fundamental characteristics of an oil field are well known. To achieve this, a fully integrated reservoir simulation approach was used. In this thesis a representative reservoir model for the production unit 209-33 has been developed. It is also shown that the production behaviour of the latest well cannot be deduced from the actual reservoir behaviour. Therefore, possible technical causes for water production have been proposed. Based on this model various future development scenarios have been investigated, with the result that a single new vertical infill well holds the greatest economic potential. Within the first 10 years an additional recovery of about 22,000 sm³ of crude oil can be expected, which corresponds to a recovery factor increase from 38.9 % to 41.5 %.