It is still a huge problem for the Geothermal Energy sector worldwide, that investigation and interaction tools for many purposes are barely available, affordable or accessible. For this reason for many problems occurring in geothermal plants like Staufen (Germany) or Soultz (France), just to name some newer examples, the causes are not fully recognized and solutions are therefore hard to find. There are many wells worldwide with very high temperatures like in the Geysers field, Soda Lake or Fenton Hill in the USA which represents a huge challenge for investigation operations. This situation reinforces the fears in the public and inhibits the growth of geothermal energy, which stays still way behind its potential as base-load supplier. The only promising way to overcome this situation is to provide tools for widespread borehole operations to those who need them. This is the target of the ZWERG-project advanced at the Karlsruhe Institute of Technology KIT. In 2013 the ZWERG platform for standardized development of borehole tools, as well as the concept of a cooling system based on this platform, where firstly presented during the 38th geothermal workshop at Stanford University. In 2014 further results for the problem of cooling borehole tool electronics and the GeoKam-project for the development of a video inspection system for borehole depths of 4000 m and ambient temperatures up to 200 °C have been presented in their current status there too. Since then the development of the named ZWERG tools advanced technologically and new development targets have been affiliated to the platform. The GeoKam project is in its final phase, where it has to be prepared for the in situ test. Therefore it is tested in an autoclave with pressures up to 600 bar and ambient temperatures up to 200 °C to proof the thermo-mechanical and liquid tightness. Further different cooling system designs are tested, evaluated and optimized to provide a sufficient cooling period for the cameras and the electronics. For providing unlimited operation periods in hot surroundings, a borehole adjusted refrigerator is being developed. In an especially constructed test-bed, the designed components are tested and the thermodynamic process is investigated under realistic conditions. Besides the experiments on complete systems the test-hall provides room for diverse tests on small components repeatedly used in different tools. An example is an experiment to test the mechanical load ability of fiberglass wirelines under variation of stress over long time periods. Another one is test of the influence of high operation temperatures on the stability and the light intensity of special LEDīs. The work on ZWERG has just been started. For the next years further development projects regarding the interconnection and resistance of materials or the safe visit of open holes are planned. Besides the aim to improve the investigation possibilities in boreholes for a better understanding of the conditions down there and a greater acceptance of the technology, there is also the vision to provide the possibility for versatile interactions in boreholes. Based on the solutions for general problems like pressure and corrosion resistant housings, cooling of electronics or others, advanced tools i.e. for the reparation of casing leakages or other borehole interactions are realizable. In combination with video inspection using GeoKam this would be a giant step forward for fixing many problems of geothermal plants. The infrastructure for testing tools and concepts under realistic conditions, provided through the KITīs geothermal test-hall, is an important element for the developments and is therefore steadily improved and enlarged.

Press the Back button in your browser, or search again.

Copyright 2015, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.