Transport of Geothermal Fluids along Dikes and Fault Zones
Field observations of active and fossil natural geothermal fields indicate that geothermal fluids are primarily transported along dikes and fault zones. Fluid transport along dikes (commonly through fractures at their margins) is controlled by the cubic law where the volumetric flow rate depends on...
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ftmdpi:oai:mdpi.com:/1996-1073/15/19/7106/ 2023-08-20T04:07:30+02:00 Transport of Geothermal Fluids along Dikes and Fault Zones Agust Gudmundsson 2022-09-27 application/pdf https://doi.org/10.3390/en15197106 EN eng Multidisciplinary Digital Publishing Institute H2: Geothermal https://dx.doi.org/10.3390/en15197106 https://creativecommons.org/licenses/by/4.0/ Energies; Volume 15; Issue 19; Pages: 7106 geothermal systems permeability fault damage zone fault core intrusions Darcy’s law cubic law Text 2022 ftmdpi https://doi.org/10.3390/en15197106 2023-08-01T06:39:21Z Field observations of active and fossil natural geothermal fields indicate that geothermal fluids are primarily transported along dikes and fault zones. Fluid transport along dikes (commonly through fractures at their margins) is controlled by the cubic law where the volumetric flow rate depends on the aperture of the fracture in the 3rd power. Dikes (and inclined sheets) also act as heat sources for geothermal fields. In high-temperature fields in volcanoes in Iceland dikes and inclined sheets constitute 80–100% of the rock at crustal depths of 1.5–2 km. Holocene feeder-dikes are known to have increased the activity of associated geothermal fields. Fault zones transport geothermal fluids along their two main hydromechanical units, the core and the damage zone. The core is comparatively thin and primarily composed of breccia, gouge, and clay and related low-permeability porous materials. By contrast, the fault damage zone is characterised by fractures whose frequency is normally highest at the contact between the core and the damage zone. Fluid transport in the damage zone, and in the core following fault slip, is controlled by the cubic law. During non-slip periods fluid transport in the core is primarily controlled by Darcy’s law. Secondary mineralisation (forming mineral veins and amygdales) tends to reduce the fault-zone permeability. Repeated earthquake activity is thus needed to maintain the permeability of fault zones in active natural geothermal fields. Text Iceland MDPI Open Access Publishing Energies 15 19 7106 |
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MDPI Open Access Publishing |
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English |
topic |
geothermal systems permeability fault damage zone fault core intrusions Darcy’s law cubic law |
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geothermal systems permeability fault damage zone fault core intrusions Darcy’s law cubic law Agust Gudmundsson Transport of Geothermal Fluids along Dikes and Fault Zones |
topic_facet |
geothermal systems permeability fault damage zone fault core intrusions Darcy’s law cubic law |
description |
Field observations of active and fossil natural geothermal fields indicate that geothermal fluids are primarily transported along dikes and fault zones. Fluid transport along dikes (commonly through fractures at their margins) is controlled by the cubic law where the volumetric flow rate depends on the aperture of the fracture in the 3rd power. Dikes (and inclined sheets) also act as heat sources for geothermal fields. In high-temperature fields in volcanoes in Iceland dikes and inclined sheets constitute 80–100% of the rock at crustal depths of 1.5–2 km. Holocene feeder-dikes are known to have increased the activity of associated geothermal fields. Fault zones transport geothermal fluids along their two main hydromechanical units, the core and the damage zone. The core is comparatively thin and primarily composed of breccia, gouge, and clay and related low-permeability porous materials. By contrast, the fault damage zone is characterised by fractures whose frequency is normally highest at the contact between the core and the damage zone. Fluid transport in the damage zone, and in the core following fault slip, is controlled by the cubic law. During non-slip periods fluid transport in the core is primarily controlled by Darcy’s law. Secondary mineralisation (forming mineral veins and amygdales) tends to reduce the fault-zone permeability. Repeated earthquake activity is thus needed to maintain the permeability of fault zones in active natural geothermal fields. |
format |
Text |
author |
Agust Gudmundsson |
author_facet |
Agust Gudmundsson |
author_sort |
Agust Gudmundsson |
title |
Transport of Geothermal Fluids along Dikes and Fault Zones |
title_short |
Transport of Geothermal Fluids along Dikes and Fault Zones |
title_full |
Transport of Geothermal Fluids along Dikes and Fault Zones |
title_fullStr |
Transport of Geothermal Fluids along Dikes and Fault Zones |
title_full_unstemmed |
Transport of Geothermal Fluids along Dikes and Fault Zones |
title_sort |
transport of geothermal fluids along dikes and fault zones |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2022 |
url |
https://doi.org/10.3390/en15197106 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Energies; Volume 15; Issue 19; Pages: 7106 |
op_relation |
H2: Geothermal https://dx.doi.org/10.3390/en15197106 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/en15197106 |
container_title |
Energies |
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15 |
container_issue |
19 |
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7106 |
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1774719162363412480 |