The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin

Abstract The thermal structure of continental crust is a critical factor for geothermal exploration, hydrocarbon maturation and crustal strength, and yet our understanding of it is limited by our incomplete knowledge of its geological structure and thermal properties such as hydrogeologic and thermo...

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Main Authors: Alexandre Lemenager, Craig O’Neill, Siqi Zhang, Morgan Evans
Format: Article
Language:English
Published: SpringerOpen 2018-05-01
Series:Geothermal Energy
Online Access:http://link.springer.com/article/10.1186/s40517-018-0092-5
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spelling doaj-ddba1cf63fb34d64ad2bf9dbf54c19cc2020-11-25T01:34:23ZengSpringerOpenGeothermal Energy2195-97062018-05-016112710.1186/s40517-018-0092-5The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney BasinAlexandre Lemenager0Craig O’Neill1Siqi Zhang2Morgan Evans3Macquarie UniversityMacquarie UniversityMacquarie UniversityMacquarie UniversityAbstract The thermal structure of continental crust is a critical factor for geothermal exploration, hydrocarbon maturation and crustal strength, and yet our understanding of it is limited by our incomplete knowledge of its geological structure and thermal properties such as hydrogeologic and thermo-mechanical feedbacks that come into play. One of the most critical parameters in modelling upper crustal temperature is thermal conductivity, which itself exhibits strong temperature dependence. In this study, we integrate new laboratory measurements of the thermal conductivity of Sydney Basin rocks under varying temperatures, with finite-element geothermal models of the Sydney Basin using deal.II (Bangerth et al. in ACM Trans Math Softw (TOMS) 33:24, 2007). Basin geometry and structure are adapted from Danis et al. (Aust J Earth Sci 58:517–42, 2011), which quantified the extent of Triassic sediment, Permian coal measures, Carboniferous volcanics and thickness of the crystalline crust. We find that temperature-dependent thermal conductivity results in lower lateral variations in temperature compared to constant thermal conductivity models. However, the average temperatures at depth are significantly higher when temperature-dependent thermal conductivity effects are included. A number of regions within the Sydney Basin demonstrate temperatures above 150 °C at depths of less than 2000 m in these models, for instance NW of Singleton, exhibits a strong thermal anomaly, demonstrating the potential for geothermal prospectivity of the region from experimentally constrained thermal parameters.http://link.springer.com/article/10.1186/s40517-018-0092-5
collection DOAJ
language English
format Article
sources DOAJ
author Alexandre Lemenager
Craig O’Neill
Siqi Zhang
Morgan Evans
spellingShingle Alexandre Lemenager
Craig O’Neill
Siqi Zhang
Morgan Evans
The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
Geothermal Energy
author_facet Alexandre Lemenager
Craig O’Neill
Siqi Zhang
Morgan Evans
author_sort Alexandre Lemenager
title The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
title_short The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
title_full The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
title_fullStr The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
title_full_unstemmed The effect of temperature-dependent thermal conductivity on the geothermal structure of the Sydney Basin
title_sort effect of temperature-dependent thermal conductivity on the geothermal structure of the sydney basin
publisher SpringerOpen
series Geothermal Energy
issn 2195-9706
publishDate 2018-05-01
description Abstract The thermal structure of continental crust is a critical factor for geothermal exploration, hydrocarbon maturation and crustal strength, and yet our understanding of it is limited by our incomplete knowledge of its geological structure and thermal properties such as hydrogeologic and thermo-mechanical feedbacks that come into play. One of the most critical parameters in modelling upper crustal temperature is thermal conductivity, which itself exhibits strong temperature dependence. In this study, we integrate new laboratory measurements of the thermal conductivity of Sydney Basin rocks under varying temperatures, with finite-element geothermal models of the Sydney Basin using deal.II (Bangerth et al. in ACM Trans Math Softw (TOMS) 33:24, 2007). Basin geometry and structure are adapted from Danis et al. (Aust J Earth Sci 58:517–42, 2011), which quantified the extent of Triassic sediment, Permian coal measures, Carboniferous volcanics and thickness of the crystalline crust. We find that temperature-dependent thermal conductivity results in lower lateral variations in temperature compared to constant thermal conductivity models. However, the average temperatures at depth are significantly higher when temperature-dependent thermal conductivity effects are included. A number of regions within the Sydney Basin demonstrate temperatures above 150 °C at depths of less than 2000 m in these models, for instance NW of Singleton, exhibits a strong thermal anomaly, demonstrating the potential for geothermal prospectivity of the region from experimentally constrained thermal parameters.
url http://link.springer.com/article/10.1186/s40517-018-0092-5
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