Details zur Publikation

Kategorie Textpublikation
Referenztyp Tagungsbeiträge
DOI 10.5194/egusphere-egu22-10364
Lizenz creative commons licence
Titel (primär) Monitoring of an aquifer thermal storage system in the field scale using crosshole ERT
Titel (sekundär) EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022
Autor Birnstengel, S.; Günther, T.; Pohle, M.; Hornbruch, G.; Nordbeck, J.; Ködel, U.; Werban, U. ORCID logo ; Dietrich, P. ORCID logo
Quelle EGUsphere
Erscheinungsjahr 2022
Department MET
Seite von EGU22-10364
Sprache englisch
Topic T5 Future Landscapes
Abstract Heat storage in aquifer structures takes on greater significance and is therefore an important subject for risk assessment and impact analysis on groundwater resources. Geophysical methods contribute substantially to the observation of hydrogeological processes by providing information about physical subsurface properties. In order to allow for correct process interpretation, it is essential to find and evaluate their relationship to the corresponding rock-physical parameters. Therefore a heat injection experiment and a corresponding monitoring system have been developed and established in a shallow aquifer environment characterized by quaternary glaciofluvial sediments. The focus is on the investigation of coherence between geophysical proxies and the temperature distribution in the near-surface. A geological subsurface model derived from geophysical and hydrological pre-investigations has been used to simulate heat distribution and resulting electrical conductivity variations in the affected area. Tests for thermal energy storage and extraction have been conducted via Aquifer thermal energy storage (ATES) system. With time-lapse inversion we want to detect the direct impact of changing temperature distribution in the subsurface on the related electrical resistivity when heating the aquifer up to 80 °C. Rein et al. (2004) state that electrical conductivity of the subsurface depends to a great extent on water saturation. Heating up the governed pore water by 1 °C results in a linear relative electrical conductivity increase of 2.5% (Dachnov, 1962). Different inhole and cross- hole arrays at the test site assure good coverage of the heated area and pass through the monitoring routine once a day. The ongoing injection cycles consist of a heating period of 2 weeks, a down time of 3 weeks, an extraction period of 2 weeks and another down-time of 1 week followed by the next cycle. We prove the applicability of heat injection and extraction monitoring by combined crosshole ERT (and seismic) and correlated the resistivity with the directly measured temperature data of the temperature sensors additionally installed in the boreholes. At the highest observed temperature level of 75 °C the electrical conductivity increases by a factor of three. 3D inversion allows for a direct reference to the temperature distribution in the subsurface. This study provides information about the resolution capacity of crosshole ERT for heat storage systems in shallow aquifers. 
These activities have been done within the follow-on TestUM-Aquifer Project - TestUM-II ”Cyclic high temperature - Aquifer thermal energy storage (ATES) experiment” funded by the BMBF (grant 03G0898A/B).
dauerhafte UFZ-Verlinkung
Birnstengel, S., Günther, T., Pohle, M., Hornbruch, G., Nordbeck, J., Ködel, U., Werban, U., Dietrich, P. (2022):
Monitoring of an aquifer thermal storage system in the field scale using crosshole ERT
EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022
Copernicus Publications, EGU22-10364 10.5194/egusphere-egu22-10364