Université de Neuchâtel

Detection and characterization of hydraulically active fractures in a carbonate aquifer : results from self-potential, temperature and fluid electrical conductivity logging in the Combioula hydrothermal system in the southwestern Swiss Alps

Suski, B. ; Ladner, F. ; Baron, L. ; Vuataz, François-David ; Philippossian, F. ; Holliger, K.

In: Hydrogeology Journal, 2008, vol. 16, no. 7, p. 1319-1328

A geophysical and geochemical study has been conducted in a fractured carbonate aquifer located at Combioula in the southwestern Swiss Alps with the objective to detect and characterize hydraulically active fractures along a 260-m-deep borehole. Hydrochemical analyses, borehole diameter, temperature and fluid electrical conductivity logging data were integrated in order to relate electrokinetic...

Université de Neuchâtel

Remobilisation of deep Na-Cl waters by a regional flow system in the Alps: Case study of Saint-Gervais-les-Bains (France) = Remobilisation d’eaux Na-Cl profondes par un système d’écoulement régional dans les Alpes : le cas de Saint-Gervais-les-Bains (France)

Sonney, Romain ; Vuataz, François-David

In: Comptes Rendus Geoscience, 2010, vol. 342, no. 2, p. 151-161

The hydrothermal system of Saint-Gervais-les-Bains, France is located in a south western low-elevation point of the Aiguilles Rouges crystalline Massif. The crystalline rocks are not directly outcropping in the studied area but certainly exist beyond 300 m depth. Uprising waters are pumped from two different aquifers below the Quaternary deposits of the Bon Nant Valley. In the Lower Trias-Permian...

Université de Neuchâtel

Developing the ability to model acid-rock interactions and mineral dissolution during the RMA stimulation test performed at the Soultz-sous-Forêts EGS site, France = Développement des capacités de modélisation des interactions acides-roche et des dissolutions de minéraux au cours des tests de stimulation acide de type RMA réalisés sur le site SGS de Soultz-sous-Forêts (France)

Portier, Sandrine ; Vuataz, François-David

In: Comptes Rendus Geoscience, 2010, vol. 342, no. 7-8, p. 668-675

The Soultz Enhanced Geothermal System (EGS) reservoir's response to chemical stimulation is assessed by numerical simulation of coupled thermo-hydraulic-chemical processes. To assess chemical interactions between host rocks and a mixture of HCl and HF as well as its potential effects on the Soultz EGS reservoir, new modelling efforts using the FRACHEM code have been initiated. This article...

Université de Neuchâtel

Numerical modelling of Alpine deep flow systems: a management and prediction tool for an exploited geothermal reservoir (Lavey-les-Bains, Switzerland)

Sonney, Romain ; Vuataz, François-David

In: Hydrogeology Journal, 2009, vol. 17, no. 3, p. 601-616

The geothermal site of Lavey-les-Bains, Switzerland is an Alpine deep flow system in fractured crystalline rocks. Groundwater analyses since 1973 reveal a mixing process between a deep warm component (68°C and TDS 1.4 g/L) and cold shallow water. The production rate of the new deep well P600, installed in 1997, has amplified this mixing process in well P201, for which a decline in temperature...

Université de Neuchâtel

Echantillonnage des eaux souterraines : Guide pratique = Grundwasserprobenahme. Praxishilfe

Thierrin, Joseph ; Steffen, Peter ; Cornaz, Samuel ; Vuataz, François-David ; Balderer, Werner ; Looser, Michel

In: Publications de l’Office fédéral de l’environnement, des forêts et du paysage (OFEFP), 2003, p. 1-83

This guide to sampling ground water gives the nec-essary information and describes the precautions to be taken during the various phases of sampling (prepara-tion of the sampling plan, taking of samples, treatment and storage of samples) to ensure sampling quality. The main techniques for doing both measurements and analyses in the field related to the problems in sam-pling water are also...

Université de Neuchâtel

L’énergie géothermique : Un grand potentiel et de nombreuses applications

Vuataz, François-David

In: Bulletin SEV/AES, 2005, vol. 15, p. 25-31

C’est en 1904 que la géothermie industrielle a démarré avec la production d’électricité en Toscane. A partir des années 1960, des centrales électriques géothermiques voient le jour dans 24 pays. L’utilisation directe de la chaleur souterraine, notamment pour le chauffage et pour le thermalisme, s’est développée dans 70 pays. En Suisse, les sondes géothermiques verticales pour...

Université de Neuchâtel

Hydrochemical multiparameter log analysis in a shallow, heterogeneous alluvial aquifer (Wallis Canton, Switzerland)

Schürch, Marc ; Vuataz, François-David

In: Bulletin for Applied Geology, 2002, vol. 7, no. 1, p. 3-18

With the help of a hydrochemical multiparameter logging system, the vertical evolution of temperature, electrical conductivity, dissolved oxygen, as well as redox potential and pH were determined in five shallow boreholes in a heterogeneous alluvial aquifer of the upper Rhone River valley, Wallis Canton, Switzerland. The multiparameter logging was carried out both with and without pumping using a...

Université de Neuchâtel

Groundwater components in the alluvial aquifer of the alpine Rhone River valley, Bois de Finges area, Wallis Canton, Switzerland

Schürch, Marc ; Vuataz, François-David

In: Hydrogeology Journal, 2000, vol. 8, no. 5, p. 549-563

Source, type, and quantity of various components of groundwater, as well as their spatial and temporal variations were determined by different hydrochemical methods in the alluvial aquifer of the upper Rhone River valley, Bois de Finges, Wallis Canton, Switzerland. The methods used are hydrochemical modeling, stable-isotope analysis, and chemical analysis of surface water and groundwater....