The overall goal concerning this thesis is to identify, if OMV is able to improve its operational costs by renewing the existing flow line system, which is subject to internal corrosion by water and the presence of CO2 and H2S in the gas phase. Failures of the flow line system cause production losses. These costs constitute a major cost item. A model has been set up which reflects the total costs of replacing flow lines. The cost models of this investment appraisal are based on two alternatives, keeping the existing flow line system and replacing it completely. A comparison analysis of the two models is carried out with established economic methods, whereby potential benefits are identified and analyzed. Furthermore, an investigation of the relationship between the input data and the target values has been performed with a probabilistic and a deterministic sensitivity analysis. This was done to answer the question, how the target value changes with variations of the input measures. The outcome of the investment appraisal and the sensitivity analysis provide the basis for the decision whether the investment, in a new flow line, should be undertaken or rejected.