Drilling of geothermal research well in Cologne-Dellbrück, Germany completed

After about two months of drilling, the geothermal research well in in the Dellbrück district of Cologne in North Rhine-Westphalia (NRW), Germany has been completed to a depth of 802 meters. Through analysis of core samples and well data, the project seeks to determine if the Massenkalk limestone formation is a suitable geothermal reservoir.

The borehole in Cologne-Dellbrück is one of four deep research boreholes being drilled by the Geological Survey of NRW on behalf of the state government as part of the NRW Geothermal Master Plan. The drilling work is expected to provide information to municipalities and public utilities on their respective geothermal potential, upon which local authorities can implement their own projects. Further deep exploratory drilling will take place in Münster in 2027 and in Mönchengladbach in 2028.

Last year, another research borehole drilled to 1000 meters depth in Krefeld demonstrated that the Kohlenkalk limestone layer has a system of open fissures and small cavities that contain warm water. While the Kohlenkalk formation has now been proposed as a potential reservoir for geothermal production by municipalities or public utilities, this remains to be seen for the Massenkalk layer. As pointed out by Dr. Martin Salamon, Deputy Director and geologist at the Geological Survey of NRW, the Massenkalk is a type of limestone that is very typical in the NRW region.

Project manager Ingo Schäfer has stated that early indicators are promising, the water was encountered in the limestone during drilling and the drill cores show large fissures where water can move and be stored. “We can see that geothermal heat extraction works technically from numerous existing plants in southern Germany. We are now investigating whether the geology in North Rhine-Westphalia also possesses the necessary properties. Cologne serves as a reference location for us,” further explained Schäfer.

Dr. Janina Falkenberg, who is responsible for public relations in the project, also said that the level of interest for the project has been very high, both from energy experts and the general public. The findings from the research drilling and the resulting opportunities will be presented by the technical experts at a workshop after the investigations are completed, adhering to the motto: “From data to projects.”

Source: Geowärme NRW