Pilotanlage zur Entwicklung von Tiefenbohr-Verfahren mittels hydrothermaler Flamme

• Research unit: SFOE
• Project number: 102981

Key words (German)

TP0146;F-Wissens- u. Technologietransfer

Short description (German)

Die Kosten von Bohrungen haben einen entscheidenden Einfluss auf die Entwicklung der tiefen Geothermie. Die Entwicklung von kostengünstigen Alternativen zu den konventionellen mechanischen Bohrverfahren ist deshalb von grossem Interesse. Das Bohrverfahren mit hydrothermaler Flamme, englisch als "thermal spallation drilling" bezeichnet, ist eine der aussichtsreichsten Möglichkeiten, in Zukunft kostengünstige Tiefbohrungen zu erstellen.
Das Projekt der ETH Zürich will die Machbarkeit der Spallation im überkritischen Bereich anhand einer Pilotanlage demonstrieren und die wichtigen ingenieur-wissenschaftlichen Parameter für das "upscaling" in Feldversuche bestimmen. Im Weiteren sollen die Wirtschaftlichkeit der Technologie im Vergleich zur konventionellen Bohrtechnologie untersucht und erste Schritte für die kommerzielle Umsetzung unternommen werden.

Final report (English)

The project aims to the investigation of a novel drilling technology for deep geothermal heat mining. The current report is a description of the construction and commissioning of the new spallation drilling pilot plant. Its design is developed to allow for the economical and technical feasibility investigation of the technique and it is based on the findings of the preceding project carried out in our lab. The drilling technology in question makes use of a known phenomenon used in mining in the US during the seventies. Local and rapid heating of crystalline rocks with the help of a flame jet leads to the induction of extreme thermal stresses in the mass of the rock and subsequently to fracture in disc-like spalls. The impinging heat flux from the flame to the rock is the milestone of the process, the thermal stresses being directly connected with the temperature distribution in the rock specimen. The described project sets the aims even higher, by trying to characterize the aforementioned process in an aqueous high pressure (250 bar) environment, simulating the depth of a geothermal well. The new environment sets new challenges not only for the heat transfer problem and the transportation of the produced spalls, but also for the ignition of hydrothermal flames. Such flames are flames ignited in water under a pressure higher than its critical value and were previously produced only through self ignition of the reactants, a case not relevant in a drilling process, where the ignition must be safe and reproducible. The project was initiated in April 2009 and in accordance with the milestones defined at its beginning, the plant has now been built and commissioned. A detailed account of the work accomplished so far, and a brief outlook of the scheduled tasks follow a short description of the organization of the work in distinct phases and the accomplished milestones of each one. In summary the general goals of the project are: • Initial design - Planning of the pilot plant. • Construction of the plant. • Commissioning of the pilot plant. • Experimental investigation of the drilling technique and assessment of its technical and economical feasibility.

Auftragnehmer/Contractant/Contraente/Contractor:
ETH Zentrum, ETH Zürich

Autorschaft/Auteurs/Autori/Authors:
Stathopoulos,Panagiotis
von Rohr,Philipp Rudolf

Related documents

• Pilot plant for the development of a drilling technology based on the use of a hydrothermal flame - Final Report [PDF] 3'207 kB