Directional Drilling and Stimulation of a Deep Sedimentary Geothermal Reservoir

Abstract

Strata of Lower Permian sandstones and volcanics are widespread throughout Central Europe, forming deeply buried (on average, 4000-m) aquifers in the North German Basin with formation temperatures of up to 150°C. Stimulation methods to increase their permeability by enhancing or creating secondary porosity and flow paths are investigated by deep drilling. The goal is to map the potential for the generation of geothermal electricity from such deep sedimentaryreservoirs using a doublet of boreholes—one to produce deep natural hot water and the other to re-inject the water after use. For these purposes, an in situ downhole laboratory was established in Gross Schönebeck, north of Berlin, Germany (Fig. 1).