DMT investigates petrothermal energy sources: Quest for the hot stone
The search for alternative energy is currently a top priority and the solution might just lie in so-called petrothermal reservoirs. These hot underground rock strata could provide us with an ecological and economical supplementary energy supply for the future. As part of a BMU research project (German Ministry for Environment, Nature Conservation and Nuclear Safety), the Essen based technology service provider DMT GmbH & Co. KG was contracted by the Leibniz Institute for Applied Geophysics (LIAG, Hannover) to explore areas in the Schneeberg region of Sachsen with potential for hot deepwater extraction.
The on-site exploration focuses on geological faults in crystalline rock (granite, phyllite and diabase) reaching depths of up to six kilometres, some of which have already undergone mining exploration to approximately 2,000 m. It is possible that these faults may be utilised to deliver water to the hot adjacent rock strata. The heated water would then be drawn to the surface and used for energy production by geothermal power plants.
The first challenges facing the geophysicists are the particularities of the crystalline rock and of course the extreme depths to be explored. The structure of the rock can be described as especially “chaotic”. When seismic signals produced by DMT’s specialist vibro-trucks or using explosion methods are sent into the ground and reflected, the recorded results create an equally chaotic picture, which can prove difficult for the geologists and geophysicists to interpret.
In “normal” sedimentary rock these signals are reflected and refracted from horizons, faults and other geological structures while the reflexes are registered at the surface by thousands of geophones – highly sensitive microphones placed in the ground at regular intervals. With this data, 3-dimensional images of the underground can be generated to provide precise information about the geological conditions. This in turn primarily serves the exploration of natural resources such as oil, gas and geothermal energy. Furthermore, this information is vital in determining the optimal position of boreholes for later commercial use.
Due to the complexity of the matter, it was decided to tackle the project with two processes: the “classic” high definition 3D-seismic exploration using vibroseis technology will be carried out in a 100 km² zone in addition to seismic blasting in the surrounding area. DMT experts and their cooperation partners from LIAG and TU Bergakademie in Freiberg will set up a further 24 seismic survey points in a star formation within a 30 km radius of the core area. This should identify any upright faults, which would be of particular interest for generating energy.
As well as taking care of the necessary permits required under public and private law according to § 39 of the Federal Mining Act, DMT is in charge of the topographical measurements, the 3D seismic exploration as well as the drilling and detonation for the “star” experiment and the documentation of all acquired data. However, IPS GmbH, Celle and Celler Brunnenbau GmbH & Co. KG will be subcontracted to carry out part of the work.
The results of this experiment should reveal valuable information about the depths at which seismic methods can be used for tectonic exploration under these difficult conditions.
DMT GmbH & Co. KG, headquartered in Essen, Germany, is an independent engineering and consulting company, active at international scale. With a permanent staff of about six hundred and a further two hundred and fifty contract associates, DMT provides assistance in the form of individualized consulting and services tailored to client needs. The firm also acts as an impartial assessor. The firm’s activities focus on the fields of natural resources exploration, safety in buildings, construction and infrastructure projects, mining, cokemaking technology, product testing and industrial metrology. DMT is a member of the TÜV NORD Group.
About Exploration & Geosurvey
Using methods and techniques drawn from the fields of geology and hydrogeology, geophysics, geodetics and geotechnology, the Exploration & Geosurvey Division supplies the data needed to achieve planning reliability for the extraction of natural resources (oil and gas, coal, salt, deep geothermal energy and others), for relieving the environment (carbon capture and sequestration, reducing CO2 emissions etc.) and for special-purpose civil engineering. Our work, concentrated in a single company and reaching all around the world, begins with planning, includes surveying and interpretation and extends to modeling and the final evaluation. And to ensure the very best results we also develop, operate and market our own geosurveying systems.
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Exploration & Geosurvey Division
Telephone +49 (0) 201 172-1970
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DMT GmbH & Co. KG
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