Geothermics

Journal: Geothermics

Abbreviation

Geothermics

Publisher

Elsevier

ISSN

0375-6505

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Publications 1 - 10 of 48

High temperature instruments and methods developed for supercritical geothermal reservoir characterisation and exploitation—The HiTI project
Ásmundsson, Ragnar; Pezard, Philippe; Sanjuan, Bernard; et al. (2014)
Geothermics
GeoProp: A thermophysical property modelling framework for single and two-phase geothermal geofluids
Merbecks, Tristan Leonard; Moreira Mulin Leal, Allan; Bombarda, Paola; et al. (2025)
Geothermics
The techno-economic evaluation of geothermal resources requires knowledge of the geofluid's thermophysical properties. While the properties of pure water and some specific brines have been studied extensively, no universally applicable model currently exists. This can result in a considerable degree of uncertainty as to how different geothermal resources will perform in practice. Geofluid modelling has historically been focused on two research fields: 1) partitioning the geofluid into separate phases, and 2) the estimation of the phases’ thermophysical properties. Models for the two fields have commonly been developed separately. Recognising their potential synergy, we introduce GeoProp, a novel geofluid modelling framework, which addresses this application gap by coupling existing state-of-the-art fluid partitioning simulators, such as Reaktoro, with high-accuracy thermophysical fluid property computation engines, like CoolProp and ThermoFun. GeoProp has been validated against field experimental data as well as existing models for some incompressible binary fluids. We corroborate GeoProp's efficacy at modelling the thermophysical properties of geothermal geofluids via a case study on the heat content of different geofluids. Our results highlight the importance of accurately characterising the thermophysical properties of geofluids in order to quantify the resource potential and optimise the design of geothermal power plants.
CCS coupled with CO2 plume geothermal operations: Enhancing CO2 sequestration and reducing risks
Hau, Kevin Peter; Brehme, Maren; Rangriz Shokri, Alireza; et al. (2025)
Geothermics
The transition to a low-carbon economy is essential for mitigating climate change, particularly in hard-to-abate sectors. Carbon Capture Utilisation and Storage (CCUS) is expected to play a pivotal role in this transition. This numerical study integrates CO₂ Plume Geothermal (CPG) systems with conventional CCS using field data from the Aquistore CCS project. By employing an integrated subsurface-surface modelling workflow, we simulate and compare two 30-year scenarios with nearly identical masses of sequestered CO₂: a) Business-as-usual CCS and b) coupled CPG-CCUS The results suggest that coupled CPG-CCUS operations provide a stable source of geothermal energy, which could potentially reduce or offset energy costs, such as those associated with the CO₂ capturing process. Additionally, coupling CPG with CCS enhances CO₂ sequestration efficiency by increasing CO₂ mass density in reservoir regions that become thermally depleted due to the sustained injection of CO₂ at temperatures lower than the native reservoir temperature. Although thermally depleted regions develop during both CCS and CPG-CCUS operations, they are significantly more pronounced during the latter due to the combined effect of both cold CO₂ injection and heat extraction. Moreover, CPGCCUS operations result in a more concentrated CO₂ plume around the wells. While the production well induces a pressure gradient, this gradient primarily directs fluid flow along the injection-to-production well axis, effectively focusing the CO₂ plume and limiting widespread lateral diffusion of the fluids (brine and CO₂) to the far-field reservoir. This localised CO₂ accumulation improves CO₂ plume control and reduces risks associated with uncontrolled CO₂ migration, thereby enhancing the predictability of CO₂ accumulation. This synergistic combination of CCS and CPG operations offers a pathway for the energy transition, enhancing both the CCS technology and the geothermal resource potential, while improving CO₂ sequestration safety.
Induced seismicity risk analysis of the 2006 Basel, Switzerland, Enhanced Geothermal System project
Mignan, Arnaud; Landtwing, D.; Kästli, Philipp; et al. (2015)
Geothermics
Brine displacement by CO2, energy extraction rates, and lifespan of a CO2-limited CO2-Plume Geothermal (CPG) system with a horizontal production well
Garapati, Nagasree; Randolph, Jimmy B.; Saar, Martin O. (2015)
Geothermics
Advanced well model for superhot and saline geothermal reservoirs
Lamy-Chappuis, Benoit; Yapparova, Alina; Driesner, Thomas (2022)
Geothermics
We present a new well model aimed at simulating deep and superhot geothermal wells within reservoir-scale flow models. The model uses a classic multi-segment approach to solve the well hydrodynamics but also includes several important features significantly expanding its capabilities. Firstly, we use thermodynamic tables allowing us to accurately model fluids at all relevant pressures, temperatures and salinity conditions up to magmatic conditions. The well model can account for the transport of dissolved NaCl salt and its potential precipitation in the form of halite. Secondly, the model includes an air phase and incorporates the transient displacement of the air-water interface in the well. This allows us to simulate the starting of the well using the air pressurization technique. Lastly, the well model is coupled to an unstructured reservoir grid on which magma bodies and feed zones can be explicitly represented. This paper introduces the technical details of the well model and presents several applications showcasing what insights could be gained concerning the performance of deep geothermal wells. We conducted two sets of simulation: first, we simulated a deep resource resulting from strongly enhanced heat flux with a well and a single feedzone; we assessed the effects of the feedzone's permeability, temperature and salinity on well starting and initial performance. In a second set of simulations, we used a more realistic hydrothermal system, driven by a magmatic intrusion. From the results we illustrate examples of which factors control the ability of the well to self-start, if and how air pressurization can aid starting wells, how production from a supercritical resource created near a magmatic intrusion may evolve over up to 200 years, and how halite precipitation may rapidly clog the well in case of production from saline superhot resources.
Hydromechanical characterization of a fractured crystalline rock volume during multi-stage hydraulic stimulations at the BedrettoLab
Bröker, Kai Erich Norbert; Ma, Xiaodong; Gholizadeh Doonechaly, Nima; et al. (2024)
Geothermics
Multi-stage hydraulic stimulation experiments were conducted at the Bedretto Geothermal Testbed (Switzerland) at a depth of over 1 km to study seismo-hydromechanical processes at the hectometer scale. Eight intervals with a total length of 206 m were stimulated within a densely monitored, fractured granitic rock volume. Geological characterization shows that all intervals contain NE-SW striking, steeply dipping fractures, but the transmissivity and natural inflow vary between intervals. Reactivation pressures estimated from injectivity increases during stimulation indicate shear reactivation rather than hydraulic jacking, suggesting reactivation of pre-existing non-filled fractures. Overall, the seismo-hydromechanical response to stimulation is heterogeneous and indicates channelized flow.
The dynamic evolution of the Lahendong geothermal system in North-Sulawesi, Indonesia
Suherlina, Lily; Newson, Juliet; Kamah, Yustin; et al. (2022)
Geothermics
This study uses an integrated approach to characterize the dynamic evolution of the power-producing highenthalpy geothermal system of Lahendong, North-Sulawesi, Indonesia. Lahendong has two primary reservoirs, the southern and the northern, which have been utilised for electricity production for more than twenty years. The main focus of this study is the characterisation of heat and mass flows in the system with respect to geological structures and permeability distribution. Also, it delineates how the geothermal system has evolved and the spatial variation of the response resulting from prolonged utilization of the reservoirs. This research implemented geological structure analysis on recent surface fault mapping and pre-existing fault studies from literature. Further, the study analysed well data comprising well pressure, enthalpy, drilling program reviews and tracer tests. Hydrochemical investigation compiled new and old surface and subsurface hydrochemical evolution in both the temporal and spatial domain. The results confirm several fault trends in the study area: NESW and NW-SE are the major striking directions, while E-W and N-S are less dominant. The most apparent trends are NE-SW striking strike-slip faults, NW-SE thrust faults and N-S and E-W striking normal faults. The faults compartmentalize the reservoir. A comparison of the southern and the northern reservoir shows that the southern one is more controlled by faults; both reservoirs rely on fractures as permeability provider and are controlled by shallow hydrogeology, as derived from the integrated analysis of transient well data. Geochemical analysis shows that the reservoir fluids have generally a higher eelectrical conductivity and are closer to fluidrock equilibrium, probably due to boiling, compared to spring waters. Spring waters have generally become more acidic, which is an expected result of reservoir boiling and increased steam input to near-surface waters. The spatial distribution of changes shows a permeability evolution over time and also the role of structural permeability in response to changing reservoir conditions. Observing and recording reservoir data is highly important to understand the reservoir response to production and ensure the long-term sustainability of the system. Additionally, the data is critical for making a major difference in the reservoir management strategy.
The thermal structure and temporal evolution of high-enthalpy geothermal systems
Scott, Samuel; Driesner, Thomas; Weis, Philipp (2016)
Geothermics
The effect of thermo-elastic stress re-distribution on geothermal production from a vertical fracture zone
Patterson, James W.; Driesner, Thomas (2020)
Geothermics

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