Accéder directement au contenu Accéder directement à la navigation
Article dans une revue

New insights into hydrothermal fluid circulation affected by regional groundwater flow in the Asal rift, Republic of Djibouti

Abstract : The Asal Rift hosts a lake located in a depression at 150 m below sea level, where recharge is influenced by regional groundwater flow interacting with the Ghoubbet Sea along the coast of Djibouti. This regional groundwater flow is believed to influence hydrothermal fluid circulation, which we aim to better understand in this study, having the objective of developing concepts for geothermal exploration in the area. To this end, magnetotelluric data acquired in the Asal Rift were processed and analyzed. 1D inversion models of electrical conductivity were interpolated for interpretation. These data were then used to build a 2D hydrogeological model, allowing multiphase flow and heat transfer simulations to be performed, considering the regional groundwater flow near the surface and the site topography, in order to confirm the preferred path of fluid flow. Geophysical data analysis indicates the presence of normal faults, notably the H fault, which may act as a conduit for the circulation of hydrothermal fluids and where the hanging wall can be a hydrogeological barrier within the hydrothermal system of the Asal Rift. The results from the 2D numerical flow and heat transfer modelling show the importance of groundwater flow responsible for thermal springs located at the periphery of Asal Lake. Reservoir temperature inferred by means of geothermometry ranging from 200 to 270 °C was shown to correspond to simulated temperature at potential reservoir depth. Moreover, simulated temperature between 600 and 1700 m depth is close to the temperature profile measured in the geothermal well Asal 6 of the area, with less than 20 °C difference. Simulations indicate that hydrothermal fluid circulation is likely influenced by the regional groundwater flow controlled by the topography and the major water bodies, the Ghoubbet Sea and Asal Lake, feeding buoyant fluids interacting with a deep magmatic source and where tectonic activity created normal faults offering a preferred path for fluid circulation.
Type de document :
Article dans une revue
Liste complète des métadonnées

https://hal-brgm.archives-ouvertes.fr/hal-03324179
Contributeur : Bernard Sanjuan <>
Soumis le : lundi 23 août 2021 - 12:53:52
Dernière modification le : mardi 14 septembre 2021 - 16:35:57

Fichier

Article Asal-Djibouti_VF.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

  • HAL Id : hal-03324179, version 1

Collections

Citation

Abdek Aden, Jasmin Raymond, Bernard Giroux, Bernard Sanjuan. New insights into hydrothermal fluid circulation affected by regional groundwater flow in the Asal rift, Republic of Djibouti. Energies, MDPI, 2021. ⟨hal-03324179⟩

Partager

Métriques

Consultations de la notice

50

Téléchargements de fichiers

18