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Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit)

Abstract

Detailed knowledge of the geothermal properties (thermal conductivity and specific heat capacity) of the undergorund becomes more and more important with increasing exploitation of geothermal resources by deep vertical borehole heat exchangers or by seasonal storage installations. For this pilot study all existing thermal conductivity data of the Swiss Molasse were compiled and supplemented with new laboratory measurements on core and cutting samples from deep wells (2.5 to 3.0 W/mK). In a second step top-to-bottom thermal conductivity profiles were calculated from geophysical well logs. These profiles show a clear dependence on lithology and variations in thermal conductivity of up to 1 W/mK over 50-200 m thick intervals. In clay-rich lithofacies thermal conductivity is only slightly dependent on the sedimentary architecture, whereas, in sandy facies obvious distinctions are possible. The modelling of a theoretical 750 m long vertical borehole heat exchanger shows that the potential quality of extractable heat increases or decreases by up to 20% by varying the thermal conductivity with only {+-}0.5 W/mK. (orig.) [Deutsch] Fuer die Nutzung geothermischer Ressourcen mit tiefen Erdwaermesonden und saisonalen Speicheranlagen werden detaillierte Kenntnisse der geothermischen Eigenschaften (Waermeleitfaehigkeit und Waemekapazitaet) des Untergrundes zunehmend wichtig. Im Rahmen dieser Pilotstudie wurden saemtliche verfuegbaren Waermeleitfaehigkeits-Daten von Schweizer  More>>
Authors:
Leu, W; Greber, E; [1]  Hopkirk, R J; [2]  Keller, B; [3]  Rybach, L [4] 
  1. Geoform, Geologische Beratungen und Studien AG, Winterthur (Switzerland)
  2. Polydynamics Engineering, Maennedorf (Switzerland)
  3. Mengis und Lorenz AG, Luzern (Switzerland)
  4. ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik und Radiometrie
Publication Date:
Dec 01, 1997
Product Type:
Conference
Report Number:
ETDE-DE-597; CONF-9609413-
Reference Number:
SCA: 150303; PA: DE-97:0GH967; EDB-98:027987; SN: 97001883267
Resource Relation:
Conference: 4. meeting on geothermics - 7. experts meeting of Schweizerische Vereinigung fuer Geothermie (SVG): Geothermics - energy for the future, 4. Geothermische Fachtagung - 7. Fachtagung der Schweizerischen Vereinigung fuer Geothermie (SVG): Geothermie - Energie der Zukunft, Konstanz (Germany), 18-20 Sep 1996; Other Information: PBD: 1997; Related Information: Is Part Of Geothermics - energy for the future. Proceedings; PB: 499 p.; Geothermie - Energie der Zukunft. Tagungsband
Subject:
15 GEOTHERMAL ENERGY; SWITZERLAND; GEOTHERMAL WELLS; SEASONAL THERMAL ENERGY STORAGE; PROBES; THERMAL CONDUCTIVITY; SPECIFIC HEAT; DATA ACQUISITION; STRATIGRAPHY; GEOLOGIC SURVEYS; MAPS
OSTI ID:
573667
Country of Origin:
Germany
Language:
German
Other Identifying Numbers:
Other: ON: DE98714933; ISBN 3-932570-09-X; TRN: DE97GH967
Availability:
OSTI as DE98714933
Submitting Site:
DE
Size:
pp. 395-403
Announcement Date:
Apr 10, 1998

Citation Formats

Leu, W, Greber, E, Hopkirk, R J, Keller, B, and Rybach, L. Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit). Germany: N. p., 1997. Web.
Leu, W, Greber, E, Hopkirk, R J, Keller, B, & Rybach, L. Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit). Germany.
Leu, W, Greber, E, Hopkirk, R J, Keller, B, and Rybach, L. 1997. "Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit)." Germany.
@misc{etde_573667,
title = {Geothermal characteristics of the molasse basin (pilot study - thermal conductivity); Geothermische Eigenschaften des Molassebeckens (Pilotstudie - Waermeleitfaehigkeit)}
author = {Leu, W, Greber, E, Hopkirk, R J, Keller, B, and Rybach, L}
abstractNote = {Detailed knowledge of the geothermal properties (thermal conductivity and specific heat capacity) of the undergorund becomes more and more important with increasing exploitation of geothermal resources by deep vertical borehole heat exchangers or by seasonal storage installations. For this pilot study all existing thermal conductivity data of the Swiss Molasse were compiled and supplemented with new laboratory measurements on core and cutting samples from deep wells (2.5 to 3.0 W/mK). In a second step top-to-bottom thermal conductivity profiles were calculated from geophysical well logs. These profiles show a clear dependence on lithology and variations in thermal conductivity of up to 1 W/mK over 50-200 m thick intervals. In clay-rich lithofacies thermal conductivity is only slightly dependent on the sedimentary architecture, whereas, in sandy facies obvious distinctions are possible. The modelling of a theoretical 750 m long vertical borehole heat exchanger shows that the potential quality of extractable heat increases or decreases by up to 20% by varying the thermal conductivity with only {+-}0.5 W/mK. (orig.) [Deutsch] Fuer die Nutzung geothermischer Ressourcen mit tiefen Erdwaermesonden und saisonalen Speicheranlagen werden detaillierte Kenntnisse der geothermischen Eigenschaften (Waermeleitfaehigkeit und Waemekapazitaet) des Untergrundes zunehmend wichtig. Im Rahmen dieser Pilotstudie wurden saemtliche verfuegbaren Waermeleitfaehigkeits-Daten von Schweizer Molassegesteinen kompiliert und mit Neumessungen an Kern- und Cuttingsmaterial von Tiefbohrungen ergaenzt (2.5 bis 3.0 W/mK). In einem zweiten Schritt wurden Waermeleitfaehigkeits-Profile mit geophysikalischen Bohr-Logs berechnet. Diese Profile zeigen eine deutliche Abhaengigkeit von der Lithologie mit einer Variation der Waermeleitfaehigkeit von bis zu 1 W/mK ueber 50-200 m maechtige Intervalle. In den tonigen Lithologien kann nur eine schwache Abhaengigkeit der Waermeleitfaehigkeit von der sedimentaeren Architektur beobachtet werden, wogegen in den sandigeren Intervallen eine deutliche Unterscheidung moeglich ist. Die Modellierung einer fiktiven 750 m tiefen Erdwaermesonde zeigt, dass der moegliche Waermeentzug bereits bei Variationen der Waermeleitfaehigkeit von {+-}5 W/mK um bis zu 20% ab- oder zunehmen kann. (orig.)}
place = {Germany}
year = {1997}
month = {Dec}
}