This thesis covers the methodology of the geomechanical model building and describes the requirement to continuously update a model with newly gained data from recently drilled wellbores. Such geomechanical models are used during well planning to predict important parameters like mud weight, pore pressure, in-situ stresses and favorable drilling direction, to enhance the safety of the drilling operation and reduce non-productive time and expenditures. On the basis of the Stripfing Tief 1 wellbore, drilled in the central Vienna Basin, the differences between the pre- and post-drill model are evaluated and by this the improvements which arise from integrating new data into the already existing model (provided by Baker Hughes), could be demonstrated. For a better understanding of the geomechanical model building itself, first the general methodology with necessary explanations of input parameters and workflow steps is described, to afterwards illustrate in more detail how the model building is done for the specific case of the Stripfing Tief 1 wellbore. Here the focus is on the post-drill model workflow steps which significantly differ from the pre-drill ones because the quantity of new data allows for more appropriate analysis methods or a more exact determination. For the post-drill model, built during the accomplishment of this thesis with the JewelSuiteTM program, this especially applies to pore pressure, minimum and maximum horizontal stress and stress direction. Those same parameters are addressed in a literature study where the applicability of the leak-off test analysis to determine the minimum horizontal stress and the possible generation mechanism of the overpressure, predicted and discovered in the Stripfing Tief 1 wellbore, are evaluated. Recommendations how to further improve the geomechancial model of the studied Stripfing Tief 1 wellbore by enhancing the quality of selected input parameters can be found in the respective sections as part of the discussion.