oa Seismic Prospecting of Geothermal Reservoirs in Hard Rock Environment - General Concept and Field Study

We are presenting an approach for finding realistic estimates of geothermal and hydraulic properties of deeply faulted and folded crystalline crust . The approach is based on 3D seismic reflection and geophysical borehole data. It is presented using the example of the 9.1 km deep Continental Deep Drillhole (KTB). This site contains all elements that make seismic prospecting in crystalline environ-ment often more difficult than in sedimentary units – basically complicated tectonics, spatially low-coherent strata, small scale fracturing, strong random component in the seismic velocity field, often rather scattering than reflected arrivals. Considered together these circumstances lead to a statistic approach in deriving underground models that have to be evaluated and calibrated by hydro-thermal modelling. In order to determine model uncertainties distribution functions need to be derived for all geophysical properties involved. The work concept followed during the geothermal potential assess-ment of the KTB site is applicable also for other reservoirs located in similar environment.