Geothermal energy is becoming increasingly important in view of the energy transition and the increased focus on sustainable energy sources. As a renewable energy source, it has the potential to make an important contribution to reducing CO₂ and our dependence on fossil fuels.  In 2023, OMV and Wien Energie joined forces to support the energy transition In Vienna and started the joint venture "deeep Tiefengeothermie GmbH", which combines the subsurface and surface expertise of these two companies. Vienna's goal is to make district heating generation completely climate-neutral by 2040 - a project in which geothermal energy plays a key role.

Extensive geophysical and geological work, including a large-scale 3D seismic survey in the Vienna area, has resulted in the identification of a potential geothermal reservoir in the Badenian Rothneusiedl Formation, informally called  "Aderklaaer Konglomerat". This formation is characterized by excellent hydraulic properties and occurs in a depth and temperature range appropriate for heat utilization.

Drilling of the three wells for the first project, "Hydros Seestadt", is planned to start in December 2024. This geothermal plant will generate up to 20 megawatts of climate-neutral district heating, which can supply up to 20,000 Viennese households. The saving of up to 54,000 tons of CO₂ per year underlines the climate-friendly effect. After that, up to seven geothermal plants with a total output of up to 200 megawatts are planned, generating climate-neutral district heating for up to 200,000 households.

Peter Krois holds M.Sc. and Ph.D. degrees in geology from the University of Innsbruck in Austria.  He joined OMV in 1990 and has held a variety of technical and managerial positions in Austria and abroad. Since November 2023, Peter is Managing Director of deeep Tiefengeothermie GmbH.

Fractured reservoirs are a main reservoir type for both, potential deep geothermal resources and hydrocarbons. A significant share of OMV’s past and current hydrocarbon production derives from the fractured and faulted dolostones, and dolomite rocks of various ages are currently explored by OMV, ADX, deeep and EVN for deep geothermal heat mining or hydrocarbons. The quality of fractured reservoirs depends on porosity and permeability provided by fracture and fault networks covering an extremely wide range of scales, reaching from microfractures to seismic-scale faults. We have therefore extensively analyzed fault and fracture architectures of reservoir rocks, using brittle structural geology techniques to characterize the fractured host rocks (“fractured matrix”), fault zones consisting of fault rock and damage (or process-) zones, and the density and connectivity of fracture and fault networks. Analyses aim to describe fractured matrix and faults, and understanding the processes that generate porosity/permeability supported by these structures. The latter is regarded to be of high importance for developing predictive models and forecast the characteristics of reservoirs that are likely to be found in exploration drilling.

Our previous studies focused on Middle and Late Triassic carbonates (Hauptdolomit and Wetterstein Formation) forming major reservoirs in the Northern Calcareous Alps and the Vienna Basin. The studies compiled a vast database on fracture density and associated effective porosity, and provided permeability data that describe the scale-dependent heterogeneity of these fractured and faulted carbonates. While porosity analyzes and appropriate predictive models for the porosity distribution in the reservoir are quite easy to perform, this is not the case for permeability. This is due to (1) the impossibility of analyzing Representative Elementary Volumes (REVs) of fractured rock or fault zones with respect to permeability. Permeameters typically measure 1’’ or 1.5’’ diameter plugs which are too small to capture the properties of fractured rocks with fracture spacing ranging in the scale of centimeters to tens of centimeters. (2) The bias of samples available for benchtop permeability measurements towards low permeability due to the inability to derive plugs from intensely fractured rock. (3) The inability of using industrial production data from long open-hole sections to characterize the relative contribution of fractured matrix and faults to the overall reservoir performance. Recent and current projects consequently focus on the upscaling of permeability and the correlation between porosity and permeability (phi/k functions). Outcrop-based permeability measurements at different scales including benchtop plug measurements, small-scale injection tests and core-controlled open-hole inverse production tests are used to produce sound measurements for upscaling permeability from plug to reservoir scales. Tests quantify permeability of fractured rocks with different fracture densities and the permeability distribution in fault zones.

Our studies suggest that the properties, frequency and connectivity of fault zones, fracture density in fault damage zones, the deformation mechanisms that govern fault formation and fault slip, and post-deformation cementation history are of utmost importance for the studied reservoirs.

With the ratification of the Paris Agreement in 2015 and the accelerating global climate crisis, reducing our carbon footprint has become crucial, particularly in the energy sector. Consequently, developing geothermal energy has emerged as a priority in the energy policies of many countries, including Austria and Canada. Traditional geothermal exploration for deep geothermal projects relies on conventional active seismic surveys, which are both logistically challenging and expensive. Recently, noise-based passive seismic methods combined with large and dense seismic nodal arrays have shown to be reliable and cost-effective alternatives for geothermal exploration. Although these nodes are typically designed with high corner-frequencies (>5 Hz), signals within the microseism bandwidths (0.15–1 Hz) can be accurately retrieved by enhancing the signal-to-noise ratio through seismic interferometric methods such as waveform correlation and stacking. This makes them suitable for imaging purposes. Here, we briefly introduce three case studies, where noise-based passive seismic methods are applied for geothermal exploration: one in southern Yukon, Canada, and two in the Vienna Basin, Austria. We discuss features observed in our models relevant to geothermal exploration.

In the deep underground of the Molasse basin between Regensburg, Landshut and Linz, i.e. in Lower Bavaria and Upper Austria, there is a continuous thermal water occurrence. This has been used for a long time on both sides of the state border for the extraction of healing and bathing water as well as for district heating. Decades ago, the withdrawals led to considerable pressure drops. Consequently, in the 1990s, the expert group on thermal water of the Permanent Water Commission (Ständige Gewässerkommission) had a numerical flow model created of this particular groundwater body in accordance with the Treaty of Regensburg. This was used as a basis for decision-making in the authorisation procedure, namely to predict the impact of planned thermal water developments in order to avoid negative impacts on existing uses.

However, the flow model reached its limits in the case of the thermal water wells Mehrnbach TH 1A and Mehrnbach TH 2, which were drilled in the district of Ried im Innkreis in 2011. The changes in the groundwater level caused by the extraction and reinjection of the newly constructed doublet in Mehrnbach could no longer be explained by this model. It became necessary to rethink the hydrogeological concept and to calculate a new numerical flow model in order to continue to have a reliable tool for forecasting in water rights procedures. This should take into account all new hydrogeological findings regarding the Lower Bavarian-Upper Austrian thermal groundwater body, in particular the impact of the drilling in Mehrnbach.

At the end of 2017, the consortium, consisting of GeoSphere Austria (formerly the Geological Survey of Austria), Erdwerk GmbH, the University of Leoben, RAG Austria AG (formerly RAG Rohöl-Aufsuchungs Aktiengesellschaft) and the Technical University of Munich, was contracted by the Thermalwasser expert group to develop a new hydrogeological model that takes into account all new findings, and to develop a modern numerical flow model based on this. In contrast to the previous model from the 1990s, the new flow model is a 3D model. During the modelling process, it became apparent that the significance of thermal uplift of the thermal water in the present groundwater body had been underestimated in the past. This meant that, in addition to the hydraulics, the temperature and the associated density of the water also had to be taken into account to a significant extent. The model, which was developed between 2017 and 2023, is a new, powerful tool for predicting the impact of future thermal water developments.

Energy transitions connect multiple actors and organizational arrangements around resources and energy across different geographical scales, from the local, urban, regional, and national to the global – all of which are central elements in economic geography. This talk will offer an overview of economic geography perspectives on geoenergies, contouring the depth and breadth of sub-disciplinary reach, and drawing connections with state-of-the-art policy developments and the rather recent innovation policy paradigm around societal challenges. Two conceptual developments will be foregrounded and their policy relevance explored: the CORIS approach as an orientating framework, and resource-making. Empirical insights into the practices of resource-making in research and development on novel materials for energy technologies will sketch academic practice in geography and its policy relevance. In concluding, this talk will showcase facets of the economic geography toolset for approaching an evidence base to navigate societal challenges in energy transitions.

Volcanic eruptions can be high-risk phenomena for both human lives and the economy. Energetic eruptions can produce severe consequences even in distal areas from the eruptive centre with potential economic losses of up to several trillion dollars, exacerbated by our interconnected society. Volcanoes of mafic composition (e.g., Mount Etna, Italy) account for most of the worlds active volcanic systems and can impact human activities through extraordinarily intense phenomena. The most powerful tool at our disposal to mitigate the devastating effects of volcanic activity and predict their evolution over time is volcanic monitoring. Although petrology has proven to be indispensable to understand deep magmatic mechanisms and track the evolution of complex volcanic systems over time, its use as a monitoring tool remains limited. In addition, being able to uniquely link the petrological signals contained in erupted products to the deep magmatic processes is not always straightforward. In this presentation we are going to explore new analytical techniques to identify chemical signals encrypted in minerals and to track their evolution over time. We are going to delve into the role of deformation and conduit dynamics in crystallization processes through experimental approaches and finally we will try to reconstruct the magmatic evolution occurred at Mt. Etna (Italy) during the February – April 2021 eruptive sequence, underlying the potential benefits that petrological studies can provide in volcano monitoring. In doing so, we will discuss about the future perspectives and limitations for the use of petrology as a sin-eruptive monitoring tool, with the aim of improving the response capability during volcanic crises.