Heat dissipation test with fiber-optic distributed temperature sensing to estimate groundwater flux
We measure groundwater flux and thermal parameters around a borehole performing a heat dissipation test by heating the armor of a single fiber-optic cable and interpreting the resulting heating curves with a new analytical method. The procedure is similar to thermal response tests, but benefitting f...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/353033 |
| Acceso en línea: | https://hdl.handle.net/2117/353033 https://dx.doi.org/10.1029/2020WR027228 |
| Access Level: | acceso abierto |
| Palabra clave: | Groundwater flow--Measurement Distributed temperature sensing Fiber optic Groundwater velocity Heating test Thermal properties Aigües subterrànies -- Fluxe -- Mesurament Àrees temàtiques de la UPC::Enginyeria civil::Geologia::Hidrologia subterrània |
| Sumario: | We measure groundwater flux and thermal parameters around a borehole performing a heat dissipation test by heating the armor of a single fiber-optic cable and interpreting the resulting heating curves with a new analytical method. The procedure is similar to thermal response tests, but benefitting from the high spatial and temporal resolution of distributed temperature sensing and lasting longer, so as to measure advective dissipation. Field installation relies on an innovative method in hydrogeology, which is based on the installation of the FO cable in the annular space of the well, close to the aquifer matrix. The proposed new analytical method, expands the traditional Moving Infinitesimal Line Source Model to account for the effects of the field set up and cable materials. In fact, we show that the resulting temperature build-up goes through four periods easy to identify using the log derivative of temperature (dT/d (ln(t))): Initial response, skin (cable insulation), conduction dominated and advection dominated. We test the proposed method in an unconsolidated shallow aquifer with controlled pumping. Results are of the same order of magnitude of independent estimates of groundwater velocity. |
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