Exploration of geothermal reservoirs for power generation involves high engineering and economic risks due to the need of area-wide geophysical and geological prospection and the drilling of deep boreholes. The aim of the MeProRisk Project is to develop a strategy guide line to reduce these risks by invoking an interdisciplinary task force with specialists from different fields. Scientists from three German universities and two private companies contribute with new methods in seismic modelling and interpretation, numerical reservoir simulation, estimation of petrological parameters, and 3D visualization. The key idea in MeProRisk is to understand the development of a geothermal reservoir as an iterative process. A first conceptual model for flow simulation and heat transport can be developed based on limited initial information on geology and rock properties. In the next step, additional data will be incorporated which is based on (a) new seismic interpretation methods to determine small interconnected fracture systems, (b) statistical studies on large numbers of rock samples to estimate reliable rock parameters, (c) in situ estimates of the hydraulic conductivity tensor. This results in a continuous refinement of the reservoir model where inverse modelling of water circulation allows to estimate the uncertainty and resolution of the model at every iteration step. Information on uncertainty may be used to direct further exploration and to optimize additional borehole locations..