In this thesis, the conversion of oil and gas equipment, namely a workover rig, for geothermal purposes is discussed. Precisely, the converted rig should be able to perform geothermal drilling. Thereby, the focus is on the question of whether the conversion is economically feasible and strategically wise. For this, on the one hand, the conversion itself must be examined, on the other hand, it is also necessary to take into account the general development of geothermal energy. Actually, it is the emerging development of geothermal energy in Europe and the increasingly difficult conditions in the European oil and gas industry that have led to this thesis. In countries like Austria and Germany, geothermal energy is supposed to be developed extensively in the next few years. Reasons for this trend are the intention to establish a more sustainable energy mix and the intention to obtain more independence in regard to energy supply. Due to the transition towards more sustainable energy sources, the production of fossil energy is retrogressive and oil and gas companies in central Europe are facing a very tough and challenging future. These companies are under pressure, thus, are obliged to make strategic decisions. The application of oil and gas equipment for geothermal purposes is a possible strategic change of course. Especially, because the central European geothermal drilling industry urgently needs machinery, labor, and know-how to be able to realize the planned comprehensive development of geothermal energy. If the regarded oil and gas rig were a drilling rig, it could be used for geothermal drilling without any difficulties. However, since the rig is a workover rig, it is actually incapable of drilling and needs to be supplemented by some additional systems to change that. In the course of this thesis, these systems and their according acquisition costs are identified so that, finally, the conversion costs can be determined. However, the determination of the investment´s extent is only one part of the economic feasibility study. In addition, it must also be determined whether the operation of the converted rig and the services that can be offered with the converted rig are competitive. From a technical point of view, it can be anticipated that the converted rig will able to drill to depths of up to 800 meters, thus medium-deep wells. Compared to the shallow drilling and deep drilling industry, medium-deep drilling industry is more of a niche industry with relatively few players. On one side, the sparse competition can be seen as an advantage, on the other side, the medium-deep drilling market presents hurdles that must be overcome in order to be successful. Finally, this thesis provides information about the profitability of the conversion and presents recommendations for action and possible solutions.