Research Laboratory Geothermal Energy

Second drilling in the In-situ geothermal laboratory Gro Sch nebeck successfully completed

Drill bit GFZ Potsdam
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Geothermal drilling represents a particular challenge in terms of drilling technology: Gentle "storage-compatible" drilling and optimal borehole stability are of crucial importance for the targeted use of reservoirs over an average of 20 to 30 years. In order to develop new technologies for this purpose and to minimize the costs and risks involved in the development of geothermal deposits for power generation, the GFZ Potsdam is therefore carrying out a corresponding research drilling project in Groß Schönebeck.

As early as 2000, the GFZ Potsdam expanded an old well of natural gas exploration from the 1990s into a unique geothermal experiment laboratory in the world. The advantage: Theoretical preliminary investigations can be checked in the "in-situ geothermal laboratory" 1: 1 under natural conditions. The location was chosen for its reference character, as the prevailing geology of the North German Basin is representative of large parts of Central Europe.

Experiments on site

In the meantime numerous series of experiments have been carried out at the Brandenburg research location, new methods have been tested and optimized. Research focuses on methods that can be used to specifically improve the productivity of drilling. Researchers are also developing innovative drilling technologies and strategies to increase the life of drilling tools, reduce energy and material consumption during drilling, and minimize the cost and risk of deep drilling. Such in-situ experiments at reference sites are indispensable in technology development, as they offer the opportunity to test new and immature techniques in practice and develop them further to application maturity.

Drill rig from Drilltec © GFZ Potsdam

In this respect, Groß Schönebeck is a pilot project that is perceived beyond the borders of Germany as one of the European lighthouse projects in geothermal energy. With more than ten million euros in funding, it is also one of the most important renewable energy R & D projects currently supported by the Federal Government. The project is involved in various European research collaborations such as "I-GET" or the competence network for the promotion of geothermal research in Europe "ENGINE".

New digestion technology protects the reservoir

The geothermal utilization concept of the GFZ provides for two deep wells: a so-called doublet from a production well and an injection well, as well as a sustainable thermal water cycle and an above-ground power plant. The water is to be taken from the depth via the production well and returned to the subsurface via the injection well after its thermal utilization in the power plant. display

To implement this concept at the Brandenburg research location, a second well was drilled in 2006 in Gro Sch nebeck. A long-term circulation experiment between the two wells will demonstrate in 2007/2008 that the sustainable transport and heat exchange in a thermal water cycle is ensured and that investment in a power plant is worthwhile.

3D modeling specifies bore path

Drill path and lithology of the new well GFZ Potsdam

The distance and course of the two holes are designed so that the thermal water cycle can be optimally designed. From a depth of about 2, 700 meters was drilled directionally, whereby according to Bohrtechnchnischer concept an inclined bore course was achieved. Borehole path and inclination course constantly monitored the GFZ scientists by measurements. As an indispensable instrument, the accompanying geological 3D modeling has been demonstrated. It represents an important decision-making aid for the drilling path design, with which the geometry of the target borehole can be illustrated and analyzed vis-à-vis the existing reference borehole and the actual borehole in a geological context. The pipes for securing the borehole could be adapted to the geological and geometric conditions as quickly and accurately as possible.

At the end of 2006, the final depth of the hole was reached at 4, 400.44 meters. The drilling work was carried out in such a way that the reservoir was not damaged by infiltrating drilling during the drilling, with a view to a particularly gentle excavation of the target horizons. The hole has a large diameter, which allows the installation of a large pump for the promotion of hot deep water. The course of the hole could be planned using 3D modeling, so that the drilling and injection drilling in the target area is about 475 meters, about only about 28 meters apart, with all the advantages of the short distances f Later installations.

(Ernst Huenges, GeoForschungsZentrum Potsdam, 30.03.2007 - AHE)