The geothermal industry faces several challenges in the exploration and exploitation process of deep geothermal resources. Some of these challenges include poor drilling performance, lack of bottom hole awareness, and absence of tools for real-time process optimization, resulting in significant non-productive time. In deep geothermal projects, the drilling process alone can account for a significant proportion of the overall project cost of up to 60%. To provide a solution to minimize these uncertainties and the associated costs, a data driven AI-based drilling advisory systems is being developed within the OptiDrill project. The system applies machine learning based models to optimize the drilling process for geothermal wells and at the same time increases the economic attractiveness and accessibility of geothermal energy. The drilling advisory system consists of four main modules, each addressing a different aspect of the drilling process. The four modules focus on the areas of drilling performance prediction and optimization, drilled lithology prediction, drilling problem detection and well completion and stimulation optimization. This presentation provides an overview of the OptiDrill project with a focus on the developments based on AI methods. It introduces and presents software modules focused on drilling process performance prediction and optimization as well as drilled lithology prediction. Both modules utilize artificial neural network models trained on historical drilling data from oil, gas, and geothermal projects to predict target values, such as rate of penetration and drilled formation lithology. These predictions offer valuable insights to drillers, contributing to a more effective and seamless drilling process.

Many of the planned geothermal wells to deliver hot water into already existing central heating systems of mid-size cities have to be drilled in densely populated urban areas. For a more economical drilling of geothermal wells up to 2500 m Huisman Equipment has modified and optimized the existing HM 150 ton drilling rig unit in many details.

The HMR 150 rig fulfills now all the challenges necessary for the drilling of geothermal wells. Because the pipe – and casing handler is now part of the rig trailer a drill pad size of 30 m x 30 m only is required. Only 3 people per shift are required to operate the rig, while offering hands-off semi automated tripping of drill pipes and casing up to 16 inch.

The max 8 trailerized loads result in fast crane-less rig moves, performed within one dayshift. Completed with the new developed high torque ( > 50.000 Nm ) universal top drive large diameter wells can be drilled in reversed circulation technology ( 20 inch and bigger). Wireline coring ( SQ and PQ ) can be executed as well.

Combined with the 340 bar mud pump pressure it ensures that modern down-hole-motors and down-the-hole-hammers can be operated. Noise emissions are minimized and the energy consumption is reduced clearly by the electric powered rig where even CO2 neutral operations can be achieved when connected to a power grid.

Planned mid-deep geothermal wells are now enabled by the modernized HMR 150 faster, safer, and with minimal environmental impact.

Geomachine’s geothermal solution includes the development of a revolutionary DTH drill rig that drills down to 3000 meters. In addition the concept includes a compressor (GMair35) and booster (GMair80) pattern as well as an IoT-based control system for controlling and developing the drilling process. We also support our customers with the rig’s technical operation and help improve the drilling processes.

GM2000 is a geothermal well-drilling rig that enables the efficient utilisation of geothermal heat in larger sites and district heating networks. It is the first rig in the world specially designed for drilling 3,000-metre-deep wells.

GMair35 is an economical, simple-to-use compressor. All unnecessary has been eliminated to produce compressed air with as little fuel as possible.

GMair80 powered by Keystone is a booster compressor modified for European conditions. It compresses the compressed air up to 79 bar with 70 cubic metres of air per minute.

GMTracker(DTH) is a solution for monitoring the drilling work and collecting and storing drilling data. It increases the overall efficiency of the drilling process by monitoring the drilling parameters and, if necessary, suggesting changes to optimise the process.

GM2000 Drilling Rig, GMair35 Compressor, GMair80 Booster and GMTracker IOT solution is Geomachine’s integrated geothermal product family, which gives performance and economy for drilling geothermal wells.

We have developed a versatile model that simulates transient thermal behaviours of downhole tools and the surrounding environments when drilling into hot geothermal reservoirs. Special emphasis was placed on flexibility and full transparency during development. Assessing the correct functioning of the model at the most basic level—each individual equation—is essential to understand and simulate the physics behind novel events or situations that are increasingly occurring in the geothermal domain. The thermal wellbore model predicts the temperature evolution over time along and across certain solid parts of the bottomhole assembly (BHA), drillstring, and surrounding rock, as well as in the drilling fluid column (also known as mud; within both drillpipe and annulus, respectively), when different parameters are altered. Those parameters include surface temperature, mud pit volume, mud flow rate, well diameter, depth, inclination, geothermal temperature gradient and physical properties of drillpipe, BHA, rock formation, and mud. The model results will be validated against several different datasets. Beyond quasistatic solutions, particular emphasis is given to the simulation of highly dynamic drilling operations. Temperature profiles driven by mud losses and high-temperature influxes will also be presented. The model will reveal overlooked or neglected challenges and will point towards possible strategies on how to overcome or even use them. It is a new building block with which geothermal drilling will potentially become more reliable, more productive, and more cost effective.

A rig/wellbore drilling hydraulics monitoring tool is essential for detecting and mitigating drilling problems such as plugged nozzles, cuttings accumulation, and well control issues. SINDI DRILLING is a simulation tool for real-time monitoring using rig sensor data, and offline job design calculations. The solution was developed based on practical experience and state-of-the-art science.

This tool prioritizes intuitive and user-friendly operation and is equipped with a graphical user interface (GUI) featuring dropdown buttons for easy input and results visualization. Hydraulic key parameters ensuring a safe and efficient drilling process are calculated and analyzed against measurements, including standpipe pressure (SPP), equivalent circulating density (ECD), mud loading, cuttings velocity, surge and swab pressures, and wellbore in/out-flux.

During the presentation, a drilling operations monitoring job is demonstrated using a real-life oil well sensor dataset. The process involves walking through the following configuration panels:

1. Wellbore Schematic and Surface Facility

2. Drillstring Tools and Dynamic Hydraulics Fields

3. Mud Properties and Mud Motor

4. Offline Pressure Calculation

5. Real-Time Pressure Calculation

6. SPP, ECD, Slip, and Geometry vs. MD

7. Surge and Swab

After configuring and checking inputs, the simulation runs, and the results are visualized and interpreted via the GUI. Thanks to built-in workarounds derived from oil and gas drilling experience, the model setup and calculations remain straightforward, even with limited input data.

Learnings and needs specific to geothermal drilling, especially in High Pressure High Temperature (HPHT) settings and Managed Pressure Drilling (MPD), are also elaborated.

In an effort to tackle climate change geothermal energy serves as a good alternative to fossil fuels. It is on this backdrop that the THC-Prognos project was designed. In this study, we focus on two main objectives: First is the collection and validation of available data. Second is to simplify and speed up access to quality-checked fluid data relevant for the utilization of geothermal energy in Southern Germany via GeotIS.

The sustainable use of geothermal energy requires the comprehensive understanding of the subsurface geology, temperature and fluids. It is therefore planned to map the fluid composition and other fluid parameters of Southern Germany as part of this project. This will be based on 3D geological models, the 3D temperature distribution of the subsurface and the collected hydrochemistry data sets. These maps will be created using geostatistical methods.

One of the main tasks of this project is to collect and validate hydrochemical data from existing databases, published literature, past and present projects and from partners involved in this project related to the Southern part of Germany. All these data will be used for mapping and to expand GeotIS.

The anticipated outcome of this project is to visualize the spatial variability of fluid properties in the Southern Germany and to establish GeotIS as the primary portal for geothermal fluid data in Germany. The project results will stimulate further geoscientific research and help in the planning and operation of geothermal reservoirs.

In an effort to tackle climate change geothermal energy serves as a good alternative to fossil fuels. It is on this backdrop that the THC-Prognos project was designed. In this study, we focus on two main objectives: First is the collection and validation of available data. Second is to simplify and speed up access to quality-checked fluid data relevant for the utilization of geothermal energy in Southern Germany via GeotIS.

The sustainable use of geothermal energy requires the comprehensive understanding of the subsurface geology, temperature and fluids. It is therefore planned to map the fluid composition and other fluid parameters of Southern Germany as part of this project. This will be based on 3D geological models, the 3D temperature distribution of the subsurface and the collected hydrochemistry data sets. These maps will be created using geostatistical methods.

One of the main tasks of this project is to collect and validate hydrochemical data from existing databases, published literature, past and present projects and from partners involved in this project related to the Southern part of Germany. All these data will be used for mapping and to expand GeotIS.

The anticipated outcome of this project is to visualize the spatial variability of fluid properties in the Southern Germany and to establish GeotIS as the primary portal for geothermal fluid data in Germany. The project results will stimulate further geoscientific research and help in the planning and operation of geothermal reservoirs.

New isotopic and hydrochemical investigation methods, including geothermometry, together with structural geological data were applied on the thermal fluids of the Baden-Baden area, to get detailed information on their origin and development. We used the test site, to evaluate our methods for application in deep granitic geothermal reservoirs in the Upper Rhine Graben. Changing flowrates and total dissolved solids of the thermal waters with time indicate a rather dynamic geothermal fluid system. Although the thermal waters (springs, boreholes) emerge from different lithologies (granites, schists, arkosic sandstones), major and trace element concentrations are very similar implying no significant impact of these lithologies. Application of a newly developed Na/K-geothermometer result in a reservoir temperature of c. 200°C. The thermal waters are i.a. supersaturated with respect to aragonite, quartz, and calcite, which is well in agreement with a 2000 years old sinter cone. The ratio of Cl- and Li concentrations correspond to those of deep thermal waters in the crystalline basement and Permotriassic siliciclastic rocks of the deep URG. Stable water isotope data indicate that meteoric water has interacted in the subsurface with granitic rocks, particularly supported by Sr-isotopic composition and by S- and O-isotopes indicating that SO₄ in the thermal waters can only be derived by oxidation of disseminated sulfides in basement rocks. Stress data indicate a general (N)NW-(S)SE trending S_Hmax, which may be the preferred direction of fluid transport in the crystalline basement, whereas the NE-trending structures rather act as hydraulic barriers forcing the thermal fluids to emerge to the surface.

Accurate estimation of reservoir temperature is a key factor in geothermal exploration studies. Advances in predictive algorithms can significantly improve the efficiency of geothermal energy exploration. The use of machine learning (ML) to predict reservoir temperatures has, therefore, attracted a great deal of interest. To investigate its practicality, northern Morocco was chosen as the research area, 99 water samples were taken in situ from springs and wells for research purposes, and five machine learning algorithms were applied. The results showed that our ML models outperformed traditional methods. XGBoost model demonstrated the best predictive accuracy with an R² of 0.9967. In addition, Shapley's additive explanation (SHAP) was used as an explanation technique to evaluate the predictive decisions of XGBoost by interpreting that SiO2 solute concentration is the most important variable for predicting reservoir temperature. This underlines the potential of ML for accurate prediction of reservoir temperature, offering advances in the understanding of geothermal resources.

Assessment of intergranular pressure solution (IPS) creep has substantial safety and economic importance in reservoirs for hydrocarbon production, geothermal operations, underground CO₂ sequestration, and hydrogen storage processes. IPS creep is a temperature-dependent, stress-driven deformation mechanism that alters mineral grain shapes by dissolution, precipitation, and diffusion in a chemically closed system. The mechanical compaction and chemical reactions of minerals lead to dissolution or precipitation related to alterations in porosity and permeability that impact the flow and, ultimately, the lifetime of the reservoir. IPS creep can be examined with experiments and some thermodynamic analytical solutions. Several IPS creep equations for uniaxial compaction and assumed linear kinetic relations between chemical dissolution and precipitation rates. According to the theory, the mineral grains have spherical shapes arranged in a cubic-packed form. Similar models also estimate the compaction occurred at slightly greater porosities. These models frequently overestimate compaction and strain rates by up to many orders of magnitude when the porosity is below 0.2. The reason is that the reaction rate parameters are estimated based on empirical equations in which the saturation indices of minerals are assumed constant. Moreover, the rate of change of grain diameters is set constant. A better approximation can be achieved using the thermodynamic databases and iterative time-dependent chemical equilibrium mass balance calculations that can be carried out in a geochemical computation program such as PHREEQC. The proposed algorithm combines the conventional IPS equation with geochemcal computation, is helpful for better inspection purposes, and provides good agreement with experimental results.

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.

Land surface temperature (LST) is commonly retrieved from thermal infrared remote sensing data and has been used in various applications within the field of geothermal exploration. In geothermal studies, the measured LST is assumed to arise from the combined effect of surface and subsurface processes, with the latter being of fundamental importance to characterize. However, due to diurnal solar heating and spatial heterogeneity in the heating rates of surface materials, the subsurface heat component is recognized only when it presents a high contrast against the background temperature. In this work, we introduce a single-source energy balance model named SkinTES (Surface KINetic TEmperature Simulator), developed in the Interactive Data Language (IDL) environment, for modeling and correcting high-resolution (<100 m) surface temperature data for diurnal and topographic effects. This approach combines atmospheric parameters with a bulk-layer soil model and remote-sensing-based parameterization schemes to simulate surface temperature over bare surfaces. By solving the energy balance, heat, and water flow equations for each pixel and integrating the surface and subsurface energy fluxes over time, SkinTES generates a model-simulated temperature map. This map is then contrasted with concurrent remote sensing LST data to uncover the subtle temperature anomalies arising from subsurface geothermic processes. We present the theoretical basis of the model, its parameterization schemes, and the results obtained by applying it to point-scale and ASTER thermal datasets acquired over a geologically complex sedimentary basin in Iran. The potential application of the model in geologic studies and its capability in detecting blind geothermal systems are highlighted.

The area of Abano Terme is a prominent part of the Hydrothermal Basin of the Euganean Hills. The thermal waters are extracted from wells reaching depths of over 1000 meters. The water from the deep reservoir (upper Trias “Dolomia Principale” and Giurassic limestones) has averaged temperatures of 85°C, chlorinated characteristics and is rich in dissolved silica.

The vulnerability of the Euganean hydrothermal system has led, as is typically the case in similar contexts, to the prohibition of geothermal resource exploitation using classical open-loop systems, reserving the hot water solely for sanitary-thermal use.

Abandoned hydrothermal wells offers the potential for cost-effective energy recovery through conventional DBHE arrays. FEFLOW modelling has been conducted to verify the efficiency of the exchangers by the dynamic flow condition in the reservoir, facilitated by pumping for the thermal establishments, compared to a purely conductive scheme. Detailed simulations have verified scenarios with coaxial DBHE exchangers with vacuum insulated inner tubing, capable of minimizing thermal short-circuiting between the supply and return pipes.

For newly constructed wells, exploitation scenarios with systems conceptually similar to DCL® (Dynamic Closed Loop) technology have also been verified. This technology is currently being tested particularly for exchangers in shallow geothermal systems. The DCL type application, for proper evaluation and sizing, requires the availability of an accurate reservoir geological model (as normally available in hydrothermal exploitation areas). However, as confirmed by numerical modeling, it can find excellent application in deep geothermal systems, ensuring significantly higher energy extraction than classic DBHE.

The Upper Jurassic Aquifer (UJA) in the Molasse Basin, South Germany, presents favorable conditions for geothermal energy utilization due to its high temperature and promising hydraulic properties. In the city of Munich, the reservoir offers optimal conditions for geothermal energy production, driving further research in the area to meet the growing demand for renewable heat sources. Our study focuses on the Schaeftlarnstrasse (SLS) geothermal site in Munich, the largest inner-city geothermal plant in Europe. The site consists of three SLS geothermal doublets (each consisting of an extraction well and an injection well) that were developed to facilitate the reuse of hydrothermal fluids and enhance the reservoir's natural fractures. These doublets operate within a 500 m thick UJA, intersecting its numerous features, including three matrix blocks, two normal faults separating the matrices, two damage zones around the faults, a karst zone, and a debris facies. Due to this high heterogeneity in a relatively small localization, an accurate characterization of the reservoir’s hydraulic properties is needed to understand and improve its performance. This was done in this research using a detailed numerical model that could emulate the hydraulic processes in the reservoir upon which sensitivity and parametric studies are applied. These studies were able to determine the controlling parameters and the parameter combinations responsible for altering the reservoir conditions. They also account for better decision-making in designing and operating the wells, hence facilitating a more sustainable exploitation of the UJA geothermal resources.

The demand for sustainable and renewable energy sources has intensified the exploration of geothermal reservoirs globally and in the European region. This research aims to identify potential opportunities and geothermal applications across the UK and delves into the application of play fairway analysis for geothermal reservoirs.

Play fairway analysis has been conventionally used in the oil and gas industry at the pre-exploration stage for mitigating geological risks, ranking promising sites and identifying areas with the highest potential. The comprehensive analysis integrates multidisciplinary datasets to map the elements of a prospect and create a holistic understanding of subsurface conditions.

An approach to locating geothermal resources follows the play fairway analysis workflow that identifies key components of a prospect. Based on gathered geological data key parameters controlling the distribution of geothermal systems have been identified and mapped by applying weighted cut-offs. A scoring system has been applied to rank potential prospects and eliminate high-risk areas. As a result of the work, for different geothermal types composite common risk segment maps have been created integrating reservoir-level uncertainties.

Thus, applying play fairway analysis to geothermal reservoirs allows for mitigating risks associated with critical components controlling the resource quality. The described method could be applied to identify areas with optimal conditions thereby enhancing exploration efficiency and contributing to the sustainable development of geothermal energy. The results could be utilized as a basis for subsequent resource evaluation and economic feasibility assessment.

Enhanced Geothermal Systems (EGS) involve artificially creating permeability in geothermal systems through engineering and stimulation methods. Despite over 30 EGS projects initiated since the pioneering experiment at Los Alamos National Lab in 1974, technical complexities, financial constraints, and seismicity challenges have hindered their success. This work examines all EGS projects established from 1974 to 2024, focusing on developments over the last decade. Presently, Europe leads with nine commercial and research projects, followed by North America with seven EGS endeavors. Most projects have been conducted in igneous formations. While some projects, such as Desert Peak and Fervo Energy in the USA or Landau and Rittershofen in Europe, achieved high flow rates after stimulation, many projects failed to meet commercial viability thresholds, resulting in project abandonment. Challenges also persist due to induced seismicity, especially in naturally fractured reservoirs near large fault zones. Recent advancements, like Fervo Energy's multistage fracking in non-fractured rock, offer promise in mitigating induced seismicity. A deep understanding of thermo-hydro-mechanical behaviors, careful control over injection rates, and comprehensive risk assessments remain crucial for operational safety and the further development of EGS.

As the hydrocarbon industry declines in central Europe, countless wells are left behind, providing an opportunity to use existing infrastructure and expertise in accelerating the green energy transition. TRANSGEO is a regional development project exploring the potential for producing geothermal energy from these abandoned oil and gas wells. TRANSGEO members have produced socio-economic and policy analyses of well reuse in 5 central European countries: Austria, Croatia, Germany, Hungary, and Slovenia. The socio-economic analyses focus on reusing active and abandoned boreholes in municipalities (for district heating systems and thermal baths/spas), agriculture (for greenhouses, drying, and aquaculture), and industry. Heat demand of these specific applications has been matched with the energy production potential of 5 geothermal reuse technologies (Aquifer and Borehole Thermal Energy Storage, Deep Borehole Heat Exchangers, Hydrothermal Energy, and Enhanced Geothermal Systems) to guide future geothermal development projects in choosing the most suitable options for well reuse. The economic analysis provides cost estimates for a variety of reuse situations and compares the cost of well reuse with the cost of drilling new wells, which is often much higher. The policy analysis provides information on the laws related to well ownership and reuse in the 5 countries, guidance on steps required to undertake a reuse project, and national and EU financial support and incentives. TRANSGEO is co-funded by the European Regional Development Fund through Interreg Central Europe.

As more deep hydrocarbon wells are coming to the end of production, interest in opportunities to reuse this valuable infrastructure for geothermal development is increasing. To facilitate repurposing of existing wells, the regional development project TRANSGEO is creating a variety of tools and guidance documents to inform new geothermal redevelopment projects and decrease their technical and financial risk. We have compiled a database of wells in regional sedimentary basins in five central European countries (Austria, Croatia, Germany, Hungary, and Slovenia) as the basis for an online application for selecting candidate wells for geothermal redevelopment. Additionally, engineering workflows for applying 5 geothermal reuse technologies (Aquifer and Borehole Thermal Energy Storage, Deep Borehole Heat Exchangers, Hydrothermal Energy, and Enhanced Geothermal Systems) were created based on literature and numerical modelling studies. The workflows provide information on the steps involved in evaluating and adapting a well for a new purpose. TRANSGEO is co-funded by the European Regional Development Fund through Interreg Central Europe.

The use of carbon dioxide (CO2) in geothermal power plants has gained significant attention in recent years as a means of preventing calcium carbonate scaling in the wells and submersible pumps. Calcium carbonate scaling can cause a number of problems in geothermal power plants, including reduced efficiency, increased energy consumption, and decreased power output.

The PRESUS C technology from Linde is a highly effective and reliable method of injecting CO2 below the submersible pump in geothermal power plants. This technology is capable of reducing the concentration of dissolved calcium in the geothermal fluids, thereby preventing the formation of calcium carbonate scaling.

By injecting CO2 into the geothermal fluid, the pH level of the fluid is lowered, making it less conducive to the formation of calcium deposits. This method has been proven to be highly effective, with some geothermal power plants.

Moreover, the use of CO2 injection in geothermal power plants is a relatively low-cost and environmentally friendly solution to calcium carbonate scaling. Unlike some other methods, such as acidification or the use of chemical or biological inhibitors, CO2 injection does not produce any harmful byproducts or waste.

In conclusion, the use of CO2 injection technology such as PRESUS C from Linde in geothermal power plants is an effective and sustainable solution to calcium carbonate scaling. By preventing the formation of calcium deposits, this technology can help geothermal power plants operate more efficiently and reliably, ultimately contributing to a more sustainable and low-carbon energy future.

The research project Eva-M 2.0 adopts a holistic approach to investigate and compare two methods for mitigating calcium carbonate scaling in geothermal plants located in the Bavarian Molasse basin. The first method involves the injection of an environmentally friendly liquid polymer inhibitor, while the second employs CO₂ injection. The study incorporates comprehensive hydrochemical and microbiological monitoring, alongside assessments of biological and thermal degradability, corrosion, and fluid-rock interaction with the reservoir. This paper presents the results related to the economic efficiency of both scaling mitigation methods, focusing on key performance indicators. The results demonstrate that both methods effectively prevent scaling, thereby enhancing the economic efficiency of medium-enthalpy hydrogeothermal projects.

Ground source heat pumps coupled to shallow borehole heat exchanger (BHE) fields represent a low greenhouse gas emission technology to provide space heating and cooling. In district heating applications the resulting multi-source energy systems can be quite complex, which makes numerical system simulation a useful approach for different design stages. Many different BHE models with specific advantages and drawbacks are available, and their limitations are not always clear to the user at first sight. In the present study, we compare different BHE field models that can be used in system simulation (TRNSYS, Modelica) regarding their long and short-term accuracy and limitations, using the example of two residential districts in Darmstadt, Germany. While most models are suitable for an early design stage, accurate short-term results in the range of a few minutes are usually not as straightforward to obtain.

To optimize the performance and sustainability of a borehole heat exchanger (BHE) system, it is critical to accurately estimate the potential of the geothermal source. The focus of this study is to utilize monitoring data to improve the accuracy of geothermal potential estimates for an BHE site in operation. Initially, a numerical model was developed for a specific BHE site based on site characteristics such as geological background, groundwater seepage condition, and surface solar radiation. The model was calibrated based on the monitored energy balance and temperature datasets during BHE operation. To estimate the geothermal potential of the site, we employed Monte Carlo simulations based on assigning various heat loads for the BHE system. Through sensitivity analysis, a robust data-based relationship, also known as a surrogate model, was established between the heat load parameters and the key performance indices of the BHE system. The surrogate model enables efficient calculation of BHE performance indices for a given heat load parameter. This provides the possibility to obtain the optimal heat load strategy to maximize the geothermal potential. Finally, an optimization algorithm was used to obtain an accurate prediction of the site's geothermal potential with an objective function aiming at maximizing heat extraction from BHEs. The innovative approach presented in this study emphasizes the importance of combining monitoring data with advanced numerical modeling techniques. The resulting methodology not only improves the reliability of geothermal potential assessment, but also provides a scalable framework applicable to other BHE sites, facilitating more efficient and sustainable geothermal energy utilization.

Horizontal Ground Heat Exchangers (HGHE) installed by utilizing Horizontal Directional Drilling (HDD) have been proven to be a cost-efficient alternative to install new Ground Heat Exchanger (GHE). A big advantage of this technology is the possibility to install HGHE in places where otherwise space would be a limiting factor.

For this research two HDD drilled boreholes were installed in Saga City, Japan. The boreholes have a diameter of 114,3 mm and a length of 59 m and 56 m as well as a depth of 5 m and 9,5 m respectively. In March 2022 a Thermal Response Test (TRT) was conducted and showed the influence of rain on the system. Bases on this test, the installed HGHE and the geology of the location a numerical model was developed in FEFLOW and validated using the measured temperatures at the turning point and the outlet of the system. The model was then used to conduct long time simulations to show the influence of water injection into the borehole. Furthermore, sensitivity studies have been conducted to investigate the influence of the borehole on the efficiency of water injection and determine optimal well design. The results showed the influence of different well paths, the distance between the boreholes and the long-term effects of water injection on the ground.

As climate change progresses, Europe has been experiencing increasingly severe and frequent summer heat waves, leading to a surge in residential cooling demand. Traditional methods of air conditioning, while effective, contribute to significant energy consumption and greenhouse gas emissions, exacerbating the problem they aim to solve. To address this, alternative and sustainable cooling solutions must be explored and implemented.

One promising solution is shallow geothermal energy, which leverages the earth’s relatively stable subsurface temperatures to provide both heating and cooling. While shallow geothermal systems are well-established for heating applications, their potential for cooling, especially in residential settings, is not yet fully realized or appreciated. This is partly due to the inadequacies of Europe’s historical residential architecture in adapting to modern cooling needs.

Europe’s rich architectural heritage, encompassing medieval, ancient, and old buildings, was not designed with contemporary cooling demands in mind. These structures often lack the insulation and design features necessary for effective temperature regulation, making it difficult to accurately measure and meet the cooling demand. Consequently, the potential of shallow geothermal energy in Europe remains underutilized.

This paper aims to highlight the critical need to redefine geothermal potential to include its cooling capabilities. By understanding the lessons from ancient cooling systems, particularly those in Iran which successfully integrated hydrothermal passive cooling with wind energy, we can better appreciate the diverse applications of geothermal energy. Ultimately, this redefinition will help in realizing the true potential of shallow geothermal energy in meeting Europe’s residential cooling demands amidst changing climate conditions.

Background of the projects:

We calculate the heat pumps exactly according to the desired operating conditions.

These are type-tested series machines that we can combine in various sizes.

This allows us to offer solutions in the output range from approx. 350 kW to 8000 kW per cascade. Larger heat outputs can also be achieved by connecting several cascades in parallel. The specific data depends solely on the respective conditions on the source side and the heating network.

For each project, we offer a customized master control system for the heat pump system with water pumps, control units, measuring equipment, refrigerant monitoring systems and other requirements in order to be able to operate the heat generation system safely and energy-efficiently in the long term.Our factory service offers contracts for the support of the heat pumps and the master control system over the entire service life.

About Carrier

Founded by the inventor of modern air conditioning, Carrier is a world leader in high-technology heating, air-conditioning and refrigeration solutions. Carrier experts provide sustainable solutions, integrating energy-efficient products, building controls and energy services for residential, commercial, retail, transport and food service customers. Carrier is a part of Carrier Global Corporation, global leader in intelligent climate and energy solutions that matter for people and our planet for generations to come. For more information, visit www.carier.com, www.carrier.de.

Rock salt is abundant onshore Northern Germany deposited and this rock salt has mobilized and resulted in a range of features like salt pillows, salt walls and salt diapirs. Rock salt has a high thermal conductivity and with a closed loop geothermal well solution, with no fluid interaction with the subsurface, it is possible to efficiently utilize this high thermal conductivity for geothermal energy production.

A new closed loop geothermal well solution with a horizontal section can efficiently achieve utilizing this high rock salt thermal conductivity. The well is drilled to a vertical depth of 2-5 km depth with a 3-5 km horizontal section in rock salt. It can be a single well or a group of wells depending on the energy demand. Each well will be completed with the patent-pending dual vacuum tubing technology. The circulation fluid will be heated by flowing down the well outside the tubing along the geological formation in the horizontal section of the well. When the circulation fluid arrives at the toe of the well, it is returned to the surface through the inner channel of the dual vacuum tubing with a minimal heat loss as it acts as a thermoflask.

The proposed solution mitigates the issues with a conventional 2-well hydrothermal solution and can also be implemented where a conventional 2-well hydrothermal solution will not work. By taking advantage of the high rock salt thermal conductivity and the high speed of drilling in rock salt it becomes an efficient and commercially attractive solution.

Geothermal fields often require pumping systems to achieve commercial production rates and pressures. In lower-enthalpy fields, line-shaft pumps (LSPs) have traditionally been used to supply brine to binary plants, while self-flowing production wells have been relied on in higher-enthalpy fields to power flash plants. Despite their historical use, the use of LSPs poses significant challenges in geothermal applications. To address these challenges and enhance geothermal production, a new, innovative technology in the form of Electrical Submergible Pumps (ESPs) has emerged. This breakthrough in ESP technology provides a reliable and efficient solution for geothermal operators, unlocking new opportunities for reservoir optimization and energy extraction. provides a comprehensive overview of the key components of the ESP system, including the motor, protector, pump, power cable, motor lead extension, and downhole sensors. The new ESP system demonstrates improved reliability, power density, and operational efficiency by using high-efficiency permanent magnet motors, innovative encapsulation technologies, and optimized pump designs. The lecture also highlights the successful field trial of the newly developed geothermal ESP in Kizildere Field that showcased its enhanced reliability and increased production in a high-temperature environment. The key findings from this study demonstrate the remarkable success of the newly developed ESP in high-enthalpy geothermal wells in Türkiye and also it will summarize important lessons learned during the journey of designing, installing and operating ESP’s in geothermal wells.The introduction of this technology has initially boosted the production by 56% in the geothermal field subject of study.

High-temperature aquifer thermal energy storage (HT-ATES), with its high storage capacity and energy efficiency and its compatibilities with renewable energy sources, has generated widespread interest. One main criterion for a feasible HT-ATES is the thermal recovery efficiency, i.e., how much of the invested heat can be recovered. The heat lost during the HT-ATES is mainly due to the heat conduction and the density-driven buoyancy flow, which are more significant with HT-ATES compared to the conventional low-temperature ATES. Thus, understanding the fluid displacement and thermal transport processes during HT-ATES is essential for assessing the performance of HT-ATES. A group of key parameters regarding the thermal recovery efficiency for HT-ATES are identified in this study. The numerical model is set for a typical HT-ATES based on the geological in the Burgwedel region and the designed operational parameters. Over one thousand cases are simulated for a sweep of the key parameters for multiple cycles and storage volumes, and the resulting recovery efficiency for each case is obtained. The hot water injection and displacement processes and the correlation between the recovery efficiency and the key parameters are investigated. The correlation functions are built to estimate the thermal recovery efficiency, which can be used for a quick assessment of potential HT-ATES sites when the properties of the aquifer are known. Additionally, the possibility of several measures to improve the thermal recovery efficiency is investigated.

High-temperature heat storage deep underground can create a balance between the heat supply and the heat demand, subject to seasonal fluctuations. Proven depleted oil reservoirs can be used for heat storage. In the Upper Rhine Graben, the Tertiary hydrocarbon fields are ideal for this purpose.

The reservoir rocks of these hydrocarbon fields are characterized by the sandtones of Oligocene Meletta and Niederrödern Formation. Both are realtively thin sandstone layer of up to few tens of meters thickness, interlayered with about > 200m of marls.

Existing borehole measurements and core data from the hydrocarbon fields make it possible to reproduce the reservoir models. In addition, new studies on existing core material and cuttings can describe further properties. The resulting model describes the distribution of the petrophysical properties of the sandstone horizons and forms the basis for delineating the regional heat storage potential.

In this study, we present the results of a log analysis comprising 1200 logs from 35 boreholes north of Karlsruhe, Germany. The self-potential and resistivity logs are crucial for the precise localization of sandstones and the investigation of their spatial distribution and interlayering with the marls. By comparing these results with core data analyses from the Stutensee 1 well near the Leopoldshafen oil field, we establish a link between geophysical measurements and core material.

To visualize the rock texture and pore network, we perform micro-CT investigations on the core material of the Stutensee 1 well. These are intended to provide insight into possible cementation processes to characterize inhomogeneities in porosity and permeability.

Shallow geothermal energy is one of the energy resources with great potential to meet the heating energy demand in Norway and to release electricity for the transformation of heavy industry and transport systems. Norway's geology, which is characterised by crystalline rock, is well- suited for shallow geothermal systems. However, these systems face sustainability challenges in cold regions due to unbalanced heat extraction and injection. GENESS is a unique pilot set-up that addresses this challenge by integrating semi-deep geothermal wells and excess heat storage through borehole heat exchangers (BHEs) to balance subsurface temperatures. The innovative setup of GENESS with a variety of BHEs in 119 wells, photovoltaic-thermal (PV-T) panels, semi-deep wells, observation wells and a digital twin provides a comprehensive platform for real-time testing, data acquisition and analysis to evaluate and optimise geothermal energy extraction and storage technologies. This article introduces this unique facility at the University of Stavanger and the data collected so far. It also explains how the GENESS platform can foster interdisciplinary collaboration, increase knowledge in the fields of geology, engineering, and environmental sciences, and contribute to the development of more efficient and cost-effective geothermal systems.