| Authors |
Guglielmetti, Negro, Mauri, Vuataz, Abdelfettah, Clerc, Giroud, Marguet, Schill |
| Abstract |
During the mid 2000’s, two preliminary studies on the evaluation of shallow and deep geothermal resources of the canton of Neuchatel, Switzerland, have shown that three potential aquifers could provide interesting low enthalpy geothermal resources. From May 2010 to July 2012, the Laboratory for Geothermics of the University of Neuchatel has carried out an integrated project called GeoNE, which was funded by the energy and economy departments of the canton. The main goals of this work were, to develop geothermal projects aimed at heat production from deep regional aquifers and to strengthen the competence of the Center for hydrogeology and Geothermics of the University of Neuchâtel in ensuring transfer of technology for different actors in the private domain through the organization of different training courses and workshops. In the absence of deep wells and rare existing data providing information on the deep subsurface of the study area, several indirect exploration methods have been used in this study. Based on a synthesis of the available geological data, a series of 3D geological models were elaborated at both regional and local scales. These geological models were then used to compute the distribution of temperatures in the subsurface and predict the temperature ranges expected in the three deep aquifers. Among the indirect exploration methods deployed in this study, micro gravity surveys were carried out over an area of 145 km2 to identify the presence of underground faults and fracture zones, which might act as preferential flow paths for hydrothermal fluids. The analysis of the gaseous compounds in soils, mainly He and CO2, was also tested as its effectiveness in detecting permeable fault zone is proven for different geothermal systems. This method had however never been used in such karstic environment. As part of this project, two complementary studies were conducted for the two most urbanized areas of the canton to evaluate the utilization and distribution of the geothermal heat. They highlighted the interest of several scenarios involving the geothermal resource within the existing district heating systems. Under the technology transfer aspect of this project, a new geothermal training course in deep geothermal systems (CAS DEEGEOSYS) was conceived and organized at the University of Neuchatel. The first edition took place in 2011-2012 with 26 participants and 11 international experts teaching a total of 160 hours of courses, exercises and field trips. The main topics covered were Geology and Geophysics, Geochemistry and Hydrochemistry, Drilling and Logging, Reservoir Evaluation and Production. |