Latest results from the hybrid micro-gravity monitoring of the Theistareykir geothermal field (North Iceland)Nolwenn Portier , Jacques Hinderer , Florian Schäfer , Philippe Jousset , Kemal Erbas , Vincent Drouin , Vincent Drouin , Freysteinn Sigmundsson , Ingwar Magnusson , Gylfi Pall Hersir , Kristjan Agustsson , Agrismur Gudmundsson , Egill Juliusson , Hreinn Hjartasson , Hreinn Hjartasson & Jean-Daniel Bernard
Geothermal energy represents around 30% of the produced electricity in Iceland with a cumulative capacity being equal to 755 MWe (Ragnarsson et al., 2020). In particular, the Theistareykir geothermal plant, which is located on the Mid-Atlantic ridge in North Iceland, produces 90 MWe using two turbines in operation since autumn 2017 and spring 2018, respectively. We will report on the hybrid micro-gravity monitoring and discuss how this technique will contribute to the sustainable management of...
Energy analysis of microseismicity induced byfluid-injection in the Soultz-sous-Forˆets geothermalreservoirKamel Drif , Olivier Lengliné , Jannes Kinscher & Jean Schmittbuhl
Between 1993 and 2005, the Soultz-sous-Forˆets reservoir was stimulated through 4 different wells crossing the reservoir at two different levels R3 (about 3km deep) and R5 (about 5km deep). The figure below represents the N-S section of the reservoir with the geometry of the 4 wells. During these stimulation episodes, seismic and hydraulic data were recorded. Using hydraulic data (pressure and flow rate) and available seismic catalogs of the stimulation episodes in the Soultz-sous-Forˆets reservoir,...
The modification of the stress field induced by fluid injection into the ground can generate seismic motions. Their monitoring is a key point to limit the occurrence of impacting events. Generally, this is performed using seismic surface networks, which can be limited by a significant ambient noise level especially in urban contexts. An alternative consists in the installation of stations in the depth of wells to increase the distance with surface ambient noise sources. However,...
The CDGP [https://cdgp.u-strasbg.fr], Data Center for Deep Geothermal Energy, was created in 2016 by the LabEx G-Eau-Thermie Profonde (continuing now in ITI GeoT) [https://geot.unistra.fr/], to archive the high-quality data collected in the Upper Rhine Graben geothermal sites and to distribute them to the scientific community for R activities, taking Intellectual Property Rights into account. It manages seismological (catalogues, waveforms, focal mechanisms), seismic, hydraulic, geological, and other data related to anthropogenic hazard from different phases of...
We provided an approach to estimate hydraulic diffusivity of a single fault by solving the linear diffusion equation in a partly open rough fracture under drained conditions when applying small pressure drop fluctuations (10^-5 Pa) along the fault. In contrast to the traditional calculation for the fracture hydraulic diffusivity using parameters such as hydraulic aperture, fluid compressibility, fluid viscosity, we here directly used time-dependent pressure profile p(x, y, t) to match the analytical solution for...
Ultramafic-hosted volcanogenic massive sulfide deposits: an overlooked sub-class of VMS deposits forming in complex tectonic environments?Clifford Patten , Rémi Coltat , Malte Junge , Alexandre Peillod , Marc Ulrich , Gianreto Manatschal & Jochen Kolb
Institute of applied geochemistry, KIT, Germany;Laboratoire de Géologie, CNRS-UMR 8538, Ecole Nationale Supérieure de Paris, France;Mineralogical State Collection Munich, Germany;Department of Geological Sciences, Stockholm University, Sweden;Institut Terre et Environnement de Strasbourg, CNRS-UMR 7063, Université de Strasbourg, France;Volcanogenic massive sulphide (VMS) deposits have been recognized both in fossil and present-day settings (e.g. mid-ocean ridges (MORs), back-arcs, island-arcs, fore-arcs) and are associated with different lithologies leading to variable metal enrichments. More recently, a sub-type of VMS associated...
Role of asperities on the transition from seismic to aseismic slip using an experimental fault slip systemWeiwei Shu , Olivier Lengliné & Jean Schmittbuhl
Faults are common geological structures distributed at various depths within the Earth with different behaviors: from seismic to aseismic. The frictional stability of faults is linked to the properties of asperities that make the contact between fault surfaces. Investigating the interaction between asperities and their link with the frictional stability of faults aims at a better understanding of the intrinsic relationships between the observations of earthquake swarms and the slow local aseismic transient. Here we...
The permeability of granite deformed in the brittle regime to large strains: Implications for the permeability of fractured geothermal reservoirsMichael Heap , Hugo Duwiquet , Luke Griffiths , Laurent Guillou-Frottier , Patrick Baud & Marie Violay
Efficient fluid flow and circulation are important for an economically viable geothermal reservoir. One type of underexplored reservoir for high-temperature geothermal exploitation is a crustal fault zone, where hot fluids from depths corresponding to the brittle-ductile transition are brought to the surface via crustal-scale, permeable fault zones. To better understand the evolving permeability of reservoir rock during deformation in the brittle regime—fault formation and sliding on the fault—we performed triaxial experiments on samples of well-characterised...
University of Strasbourg8
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences2
University of Orléans1
University of Iceland1
École Polytechnique Fédérale de Lausanne1
Norwegian Geotechnical Institute1
French National Institute for Industrial Environment and Risks1
Karlsruhe Institute of Technology1