Publications
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Underlined names are links to current or past GEG members
REFEREED PUBLICATIONS IN JOURNALS
20.
Gomez-Diaz, E, A Balza Morales, PA Kukla, and M Brehme, Integrative Analysis of the Aachen Geothermal System (Germany) with an Interdisciplinary Conceptual Model, Geothermal Energy: Science, Society, and Technology, 13, 2025. https://doi.org/https://doi.org/10.1186/s40517-024-00327-0 [Download] [View Abstract]Please enter abstract here
19.
Rangel Jurado, N., X.-Z. Kong, A. Kottsova, L. Grafulha Morales, N. Ma, F. Games, M. Brehme, S.M. Bernasconi, and M.O. Saar, Reactivity of Wet scCO2 toward Reservoir and Caprock Formations under Elevated Pressure and Temperature Conditions: Implications for CCS and CO2-Based Geothermal Energy Extraction, Energy & Fuels, 2025. https://doi.org/10.1021/acs.energyfuels.4c04515 [Download] [View Abstract]Please enter abstract hereCarbon capture and storage (CCS) and CO2-based geothermal energy are promising technologies for reducing CO2 emissions and mitigating climate change. Safe implementation of these technologies requires an understanding of how CO2 interacts with fluids and rocks at depth, particularly under elevated pressure and temperature. While CO2-bearing aqueous solutions in geological reservoirs have been extensively studied, the chemical behavior of water-bearing supercritical CO2 remains largely overlooked by academics and practitioners alike. We address this knowledge gap by conducting core-scale laboratory experiments, focusing on the chemical reactivity of water-bearing supercritical CO2 (wet scCO2) with reservoir and caprock lithologies and simulating deep reservoir conditions (35 MPa, 150 °C). Employing a suite of high-resolution analytical techniques, we characterize the evolution of morphological and compositional properties, shedding light on the ion transport and mineral dissolution processes, caused by both the aqueous and nonaqueous phases. Our results show that fluid–mineral interactions involving wet scCO2 are significantly less severe than those caused by equivalent CO2-bearing aqueous solutions. Nonetheless, our experiments reveal that wet scCO2 can induce mineral dissolution reactions upon contact with dolomite. This dissolution appears limited, incongruent, and self-sealing, characterized by preferential leaching of calcium over magnesium ions, leading to supersaturation of the scCO2 phase and reprecipitation of secondary carbonates. The markedly differing quantities of Ca2+ and Mg2+ ions transported by wet scCO2 streams provide clear evidence of the nonstoichiometric dissolution of dolomite. More importantly, this finding represents the first reported observation of ion transport processes driven by water continuously dissolved in the scCO2 phase, which challenges prevailing views on the chemical reactivity of this fluid and highlights the need for further investigation. A comprehensive understanding of the chemical behavior of CO2-rich supercritical fluids is critical for ensuring the feasibility and security of deep geological CO2 storage and CO2-based geothermal energy.
18.
Doonechaly, N., T. Halter, A. Shakas, M. Hefny, M. Brehme, H. Hertrich, and D. Giardini, Thermal Energy Storage and Recovery in Fractured Granite Reservoirs: Numerical Modeling and Efficiency Analysis, Geosciences, 2024. https://doi.org/10.3390/geosciences14120357 [Download] [View Abstract]Although Aquifer Thermal Energy Storage (ATES) systems are widely researched, Fractured Thermal Energy Storage (FTES) systems are comparatively underexplored. This study presents a detailed numerical model of a fractured granitic reservoir located at the Bedretto underground laboratory in Switzerland, developed using COMSOL Multiphysics. Energy efficiency was evaluated across different flow rates and well configurations, including single-well and doublet systems, as well as for two different temperatures, namely 60 °C and 120 °C. The doublet configuration at an injection temperature of 60 °C with a flow rate of 2 kg/s demonstrated the highest energy efficiency among the cases studied. Potential applications for the stored heat are discussed, with scenarios including district heating for the nearby village and greenhouse heat-ing. The results show that although FTES is associated with unique challenges, it has considerable potential as a reliable thermal energy storage method, and as a cost-effective and competitive approach for climate mitigation (considering the system is solely powered by solar-PV), particularly in regions without suitable aquifers. This study contributes insights into the viability and optimization of FTES systems and highlights the role of fracture/fault properties in enhancing energy efficiency.
17.
Marko, A, M Brehme, D Pedretti, G Zimmermann, and E Huenges, Controls of low injectivity caused by interaction of reservoir and clogging processes in a sedimentary geothermal aquifer (Mezőberény, Hungary), Geothermal Energy, 12, 2024. https://doi.org/https://doi.org/10.1186/s40517-024-00317-2 [Download] [View Abstract]Please enter abstract here
16.
Brehme, M., A. Marko, M. Osvald, G. Zimmermann, W. Weinzierl, S. Aldaz, S. Thiem, and E. Huenges, Demonstration of a successful soft chemical stimulation in a geothermal sandstone reservoir in Mezobereny (Hungary), Geothermics, 120, 2024. https://doi.org//10.1016/j.geothermics.2024.102980 [Download] [View Abstract]Geothermal energy projects often lack sufficient permeability for a sustainable operation. If natural permeability is low, it can be enhanced by stimulation treatments. These can be of thermal, hydraulic or chemical nature. The challenge is to stimulate the reservoir successfully and at the same time to do it in an environmentally safe way. This is called soft stimulation and was extensively tested in the context of the EU-Horizon2020 DESTRESS project at several geothermal sites worldwide. This paper describes the successful thermal and chemical stimulation of a geothermal doublet in Mezobereny (Hungary), targeting a sandstone reservoir at 2000 m depth. A geothermal system was constructed in 2011–2012 aimed at exploiting the geothermal potential in the Bekes Basin for a district heating system. The system with one production well and one reinjection well faced a severe injectivity drop during a 3-week operational period at the end of 2012, so that the operation had to be stopped. Historical data analysis, well logging, sampling and eventually a tailored stimulation program was designed in a ‘soft’ manner, according to standards developed in the DESTRESS project. The stimulation successfully increased the injectivity by 4 – 10 times, so that the system is ready to go into operation again.
15.
Kruisdijk, E, JF Ros, D Ghosh, M Brehme, PJ Stuyfzand, and BM van Breukelen, Prevention of well clogging during aquifer storage of turbid tile drainage water rich in dissolved organic carbon and nutrients, Hydrogeology Journal, 2023. https://doi.org/https://doi.org/10.1007/s10040-023-02602-z [Download] [View Abstract]Please enter abstract here
14.
Luo, W., A. Kottsova, P. J. Vardon, A.C. Dieudonne, and M. Brehme, Mechanisms causing injectivity decline and enhancement in geothermal projects, Renewable and Sustainable Energy Reviews, 185, 2023. https://doi.org/10.1016/j.rser.2023.113623 [Download] [View Abstract]In geothermal projects, reinjection of produced water has been widely applied for
disposing wastewater, supplying heat exchange media and maintaining reservoir
pressure. Accordingly, it is a key process for environmental and well performance
assessment, which partly controls the success of projects. However, the injectivity, a
measure of how easily fluids can be reinjected into reservoirs, is influenced by various
processes throughout installation and operation. Both injectivity decline and
enhancement have been reported during reinjection operations, while most current
studies tend to only focus on one aspect. This review aims to provide a comprehensive
discussion on how the injectivity can be influenced during reinjection, both positively
and negatively. This includes a detailed overview of the different clogging mechanisms,
in which decreasing reservoir temperature plays a major role, leading to injectivity
decline. Strategies to avoid and recover from injectivity reduction are also introduced.
Followed is an overview of mechanisms underlying injectivity enhancement during
reinjection, wherein re-opening/shearing of pre-existing fractures and thermal cracking
have been identified as the main contributors. In practice, nevertheless, mixedmechanism
processes play a key role during reinjection. Finally, this review provides
an outlook on future research directions that can enhance the understanding of
injectivity-related issues.
13.
Asnin, S.N., M. Nnko, S. Josephat, A. Mahecha, E. Mshiu, G. Bertotti, and M. Brehme, Identification of water-rock interaction of surface thermal water in Songwe medium temperature geothermal area, Tanzania, Environmental Earth Sciences, 2022. https://doi.org/10.1007/s12665-022-10594-4 [Download]
12.
Suherlina, L., J. Newson, Y. Kamah, and M. Brehme, The Dynamic Evolution of the Lahendong Geothermal System in North-Sulawesi, Indonesia. , Geothermics , 105, pp. 1-19, 2022. https://doi.org/10.1016/j.geothermics.2022.102510 [Download] [View Abstract]This study uses an integrated approach to characterize the dynamic evolution of the power-
producing high-enthalpy 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 trends of faults in the study area: NE-SW 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, perpendicular 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 south is more structurally controlled by faults; both reservoirs
rely on fractures as permeability provider and are controlled by shallow hydrogeology, derived
from the integrated analysis of transient well data.
Geochemical analysis shows that the reservoir fluids have generally higher Electrical
Conductivity and closer to fluid-rock equilibrium, probably due to boiling. 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 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.
11.
Marko, A., J. Madl-Szonyi, and M. Brehme, Injection related issues of a doublet system in a sandstone aquifer-A generalized concept to understand and avoid problem sources in geothermal systems, Geothermics, 97/102234, 2021. https://doi.org/10.1016/j.geothermics.2021.102234 [Download]
10.
Martens, S., M. Brehme, V. Bruckman, C. Juhlin, J. Miocic, A.P. Rinaldi, and M. Kühn, Preface: Special issue from the Division on Energy, Resources and the Environment at EGU2020: Sharing geoscience online, Advances in Geosciences, 54, pp. 1-5, 2020. https://doi.org/10.5194/adgeo-54-1-2020 [Download]
9.
Brehme, M., K. Nowak, D. Banks, S. Petrauskas, R. Valickas, K. Bauer, N. Burnside, and A. Boyce, A Review of the Hydrochemistry of a Deep Sedimentary Aquifer and its Consequences for Geothermal Operation – Klaipeda, Lithuania, Geofluids, 2019, 2019. https://doi.org/10.1155/2019/4363592 [Download]
8.
Brehme, M., R. Giese, L. Suherlina, and Y. Kamah, Geothermal sweetspots identified in a volcanic lake integrating bathymetry and fluid chemistry, Nature Scientific Reports, 9/16153, 2019. https://doi.org/10.1038/s41598-019-52638-z [Download]
7.
Brehme, M, S Regensburg, P Leary, F Bulut, H Milsch, S Petrauskas, R Valickas, and G Blöcher, Injection-triggered occlusion of flow pathways in geothermal operations, Geofluids, 2018, 2018. https://doi.org/10.1155/2018/4694829 [Download]
6.
Brehme, M., K. Bauer, M. Nukman, and S. Regensburg, Self-organizing maps in geothermal exploration – A new approach for understanding geochemical processes and fluid evolution, Journal of Volcanology and Geothermal Research, 336, pp. 19-32, 2017. https://doi.org/10.1016/j.jvolgeores.2017.01.013 [Download]
5.
Brehme, M., M.G. Blöcher, M. Cacace, Y. Kamah, G. Zimmermann, and M. Sauter, Permeability distribution in the Lahendong geothermal field: A blind fault captured by thermal–hydraulic simulation, Environmental Earth Sciences, 75/1088, pp. 1-11, 2016. https://doi.org/10.1007/s12665-016-5878-9 [Download]
4.
Brehme, M., F. Deon, C. Haase, B. Wiegand, Y. Kamah, M. Sauter, and S. Regensburg, Fault controlled geochemical properties in Lahendong geothermal reservoir Indonesia, Grundwasser, 21/1, pp. 29-41, 2016. https://doi.org/10.1007/s00767-015-0313-9 [Download]
3.
Deon, F., H.J. Förster, M. Brehme, B. Wiegand, T. Scheytt, I. Moeck, M.S. Jaya, and D.J. Putriatni, Geochemical/hydrochemical evaluation of the geothermal potential of the Lamongan volcanic field (Eastern Java, Indonesia), Geothermal Energy, 3/20, pp. 1-21, 2015. https://doi.org/10.1186/s40517-015-0040-6 [Download]
2.
Brehme, M., I. Moeck, Y. Kamah, G. Zimmermann, and M. Sauter, A hydrotectonic model of a geothermal reservoir – A study in Lahendong, Indonesia, Geothermics, 51, pp. 228-239, 2014. https://doi.org/10.1016/j.geothermics.2014.01.010 [Download]
1.
Brehme, M., T. Scheytt, U.E. Dokuz, and M. Celik, Hydrochemical characterization of ground and surface water at Dörtyol/Hatay/Turkey, Environmental Earth Sciences, 63/6, pp. 1395-1408, 2011. https://doi.org/10.1007/s12665-010-0810-1 [Download]
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PROCEEDINGS REFEREED
14.
Hau, K.P., M. Brehme, A. Rangriz Shokri, R. Malakooti, E. Nickel, R.J. Chalaturnyk, and M.O. Saar, Development of an Integrated Reservoir and Production System Modelling (IPSM) Workflow for simulating CO2-Plume Geothermal (CPG) Systems at the Aquistore CCS Site, Proceedings of the 49th Workshop on Geothermal Reservoir Engineering Stanford University, 2024. [Download PDF] [View Abstract]Please enter abstract hereA strong reduction in global carbon dioxide (CO2) emissions is necessary to achieve the climate targets set out in the Paris Agreement. Decarbonisation of theenergy sector, for example, requires baseload renewable energy sources, while decarbonisation of the cement and other heavy industries requires active capture and permanent (geologic) sequestration of CO2 (e.g. carbon, capture, and storage (CCS)). So far, economic constraints prevent the commercial-scale deployment of the CCS technology. Geothermal energy, as one of the renewable energy sources, can provide significant baseload energy supply but is restricted to regions with high (a) geothermal gradients and (b) rock transmissivities. Often, one of these is not given, limiting economic geothermal energy extraction.
The usage of supercritical CO2 as a geothermal working fluid by injecting it and circulating it in a closed system from the reservoir to the Earth’s surface to extract the geothermal energy can open possibilities in regions that are otherwise economically disadvantageous for geothermal energy use. Previous studies have shown that the theoretical efficiency of a geothermal system can be doubled to tripled, compared to conventional geothermal systems, due to the significantly lower kinematic viscosity of supercritical CO2, compared to H2O. This concept is commonly known as CO2-Plume Geothermal (CPG). It uses (eventually) permanently sequestered CO2 from a CCS site to a) improve the business case of CCS systems by generating geothermal power (thermal and/or electric) and b) reduce the reservoir temperatureand pressure,which in turn increases theoverall CO2 storage capacity and safety.
Inournumerical feasibilitystudy,weinvestigatethesuitabilityoftheactive,commercial-scale, research-orientedAquistoreCCSsitein Canada for a CO2-circulation demonstration test. We apply a pioneering workflow, combining (1) a field history-matched, heterogeneous reservoir model with (2) a full-physics fluid flow simulator, (3) a wellbore and (4) a simplified surface facility model (representing surface energy extraction and CO2 reinjection) in an integrated manner.
13.
Rangel Jurado, N., X-Z. Kong, A. Kottsova, F. Games, M. Brehme, and M.O. Saar, Investigating the chemical reactivity of the Gipskeuper and Muschelkalk formations to wet CO2 injection: A case study towards the first CCS pilot, Swiss Geoscience Meeting, 2023. [View Abstract]Carbon capture and storage (CCS) is expected to play a major role in societal attempts to reduce CO2 emissions and mitigate climate change. In parallel, CO2-based geothermal systems have been proposed as an innovative technology to couple CCS with geothermal energy extraction, therefore, increasing renewable energy production and unlocking industry-scale carbon capture, utilization, and storage (CCUS). The safe implementation and sustainability of both these technologies require a comprehensive understanding of how injected CO2 will interact with formation fluids and rocks in situ, especially under elevated pressure and temperature conditions. Whereas the role that CO2-bearing aqueous solutions play in geological reservoirs has been extensively studied, the chemical behavior of non-aqueous CO2-rich mixtures containing water has been vastly overlooked by academics and practitioners alike. In this study, we address this knowledge gap by conducting core-scale laboratory experiments that investigate the chemical reactivity of CO2-H2O mixtures, on both ends of the mutual solubility spectrum, towards reservoir and caprock lithologies. We conducted batch reactions on rock specimens from the Muschelkalk and Gipskeuper formations in Switzerland, subjecting them to interactions with wet CO2 under reservoir conditions (35 MPa, 150 °C) for approximately 500 hours. A wide range of high-resolution techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray computed tomography (XRCT), and stable isotope analysis, were employed to characterize the evolution of petrophysical properties, morphology, and chemical composition of the samples. Furthermore, upon experiment termination, we analyzed fluid effluents using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to gain insights into ion transport processes associated with dissolution reactions caused by both the aqueous and non-aqueous phases. Our results reveal that fluid-mineral interactions involving CO extsubscript{2}-rich supercritical fluids containing water are significantly less severe than those caused by aqueous solutions containing CO extsubscript{2}. Nonetheless, the existence of dissolved ions in the wet CO2 samples is evidence of ion transport processes caused by the gaseous phase that warrants further investigation. The experimental characterization of CO2-H2O mixtures under a wide range of reservoir and operating conditions represents a critical step in ensuring the reliability, long-term security, and technical feasibility of deploying CCS and CO2-based geothermal energy worldwide.
12.
Rangel Jurado, N., S. Kucuk, M. Brehme, R. Lathion, F. Games, and M.O. Saar, Comparative analysis on the techno-economic performance of different geothermal system types for heat generation, European Geothermal Congress, 2022. [View Abstract]Geothermal energy can play a major role in renewable energy transition efforts worldwide by replacing fossil fuels since it provides baseload, firm, and carbon-free energy. Nonetheless, in contrast to its renewable alternatives, which are harnessed on the Earth’s surface, geothermal energy resources exist underground, inherently posing challenges, risks, uncertainties, and opportunities regarding energy exploration and utilization. As a result, multiple concepts to exploit geothermal energy have been proposed over the last century with varying degrees of complexity, technological maturity, and commercial success. This paper presents a first-order comparison of the technoeconomic performance of different types of deep geothermal systems for direct heat production. The system types are Conventional Hydrothermal Systems (CHS), CO2 Plume Geothermal (CPG) systems, and Advanced [or Closed-Loop] Geothermal Systems (AGS and CO2-AGS). In this study, we consider a medium sized, standard geothermal field of intermediate depth (i.e., average continental crust geothermal gradient and
petrophysical properties), for which all naturally occurring reservoir conditions remain fixed. Our results show that water-based and open-loop configurations are
more favorable in the context of heat production for the reservoir conditions investigated here. However, the value of CO2-based and closed-loop designs is overlooked in direct-use applications. Our work highlights how important the interplay between thermal performance and hydraulic performance is to predict and regulate the techno-economic viability of deep geothermal projects over multiple decades.
11.
10.
Gomez-Diaz, E., A. Balza Morales, M. Brehme, P. Kukla, and F. Wagner, Geothermal potential in the Rhine-Ruhr region - Integration of structural analysis and a preliminary magnetotelluric feasibility study , European Geothermal Congress 2022, 2022.
9.
Hau, K.P., F. Games, R. Lathion, M. Brehme, and M.O. Saar, On the feasibility of producing geothermal energy at an intended CO2 sequestration field site in Switzerland, European Geothermal Congress 2022, 2022. [Download PDF] [View Abstract]The global climate crisis is caused by the increasing concentration of greenhouse
gases in the atmosphere. Carbon, Capture, and Storage (CCS) has been
identified as a key technology towards reaching a climate-neutral society. So far,
however, the widespread, large-scale deployment of CCS has been prevented,
among other things, by its uneconomical nature. (Zapantis et al., 2019).
To increase the economic efficiency of CCS, the stored CO2 could additionally be
used as a circulating fluid for geothermal power production, turning CCS into
simultaneous Carbon, Capture, Utilization and Storage (CCUS). The concept of
CO2-Plume Geothermal (CPG) for permanently isolating and using CO2 at the
same time was first introduced by Randolph and Saar in 2011. So far CPG has
not been tested at the field scale.
This study aims at demonstrating the feasibility of CPG for a site in Western
Switzerland. First, the study conceptually investigates the CPG power capacity
at the study site. Next, a conceptual 3D model is created using an interpreted
seismic anticline structure in the Triassic sediments of the Swiss Molasse Basin.
We conduct multi-phase fluid flow simulations based on the conceptual geologic
model to simulate realistic CO2 circulation. Injection and production rates for
multiple well configurations are assessed to calculate the expected geothermal
energy production.
The obtained results will provide an assessment of the general site suitability and
storage capacity for long-term CCUS. Also, these results will enable an
estimation of the CPG potential and geothermal power output of the site.
8.
Brehme, M., A. Marko, M. Osvald, G. Zimmermann, W. Weinzierl, S. Aldaz, S. Thiem, and E. Huenges, The success of soft stimulation: thermal, hydraulic and chemical parameters before and after stimulation at the Mezőberény site, European Geothermal Congress 2022, 2022. [View Abstract]This study describes the geothermal system in Mezőberény (Hungary) and on-site activities done within the DESTRESS project. The major challenge at the site was a poor injectivity, observed after a certain time of operation of the geothermal system. First, an evaluation of all available data of the site and the wells in the vicinity of the location has been conducted. After that, a well-logging and stimulation program was designed. The logging aimed to study a possible filling of the well with e.g. sands from the reservoir, corrosion or precipitation products, which would reduce the injectivity. A cleaning and circulation of fluids in the well was done to test the well integrity performance. The first operational phase was complemented by a thermal stimulation using cold water injection. In the second phase, we performed a chemical soft stimulation using a coiled tubing unit to inject the chemicals as close as possible to the target horizons. Lift tests before and after the injection of the chemicals and a final injection test were conducted to compare the results with the findings of the first operational phase.
Results of this study are 1) Insights into chemical, physical, and biological processes as possible injection problems based on given and new data; 2) A summary of the estimation of well integrity based on the operational experiences, tests, and logging data; and 3) An evaluation of the hydraulic properties of the system based on all test data. General conclusions are given on further development of the site.
7.
Suherlina, L., D. Bruhn, M.O. Saar, Y. Kamah, and M. Brehme, Updated Geological and Structural Conceptual Model in High Temperature Geothermal Field, European Geothermal Congress 2022, 2022.
6.
Kottsova, A., D. Bruhn, M.O. Saar, and M. Brehme, Clogging mechanisms in geothermal operations: theoretical examples and an applied study, European Geothermal Congress 2022, (in press).
5.
Marko, A., M. Toth, M. Brehme, and J. Madl-Szonyi, Assessing reinjection potential of abandoned hydrocarbon wells in the Zala region (SW Hungary) through hydraulic evaluation, European Geothermal Congress 2022, (in press).
4.
Huenges, E., J. Ellis, S. Welter, R. Westaway, K. Min, A. Genter, M. Brehme, H. Hofmann, P. Meier, B. Wassing, and M. Marti, Demonstration of soft stimulation treatments in geothermal reservoirs, Proceedings World Geothermal Congress 2021, 2021.
3.
Suherlina, L., M. Brehme, J. Newson, Y. Kamah, I.M. Galeczka, and A. Wibowo, Characterizing reservoir dynamics using hydrochemical and structural-geological data in a high-enthalpy geothermal system, Indonesia, Proceedings World Geothermal Congress 2021, 2021.
2.
Marko, A., A. Galsa, B. Czauner-Zentai, M. Brehme, and J. Madl-Szonyi, Geothermal Reinjection Problems from a Basin-scale Hydrogeological Perspective, Proceedings World Geothermal Congress 2021, 2021.
1.
Brehme, M., K. Nowak, A. Marko, S. Istvan, C. Willems, and E. Huenges, Injection triggered occlusion of flow pathways in a sedimentary aquifer in Hungary, Proceedings World Geothermal Congress 2021, 2021.
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PROCEEDINGS NON-REFEREED
3.
Rangel Jurado, N., X-Z. Kong, A. Kottsova, M. Brehme, F. Games, and M.O. Saar, Experimental characterization of the chemical reactivity of wet scCO2 under elevated pressure and temperature conditions, Society of Core Analysts Annual Symposium , 2023. [View Abstract]CO2-Plume Geothermal (CPG) systems have been proposed as an affordable and scalable strategy to deploy Capture, Utilization, and Storage (CCUS) globally. These systems utilize CO2 to extract geothermal energy from the subsurface while ensuring its permanent sequestration in geologic formations. Unlike conventional hydrothermal systems that use water or brine, CPG utilizes pure supercritical CO2 (scCO2) or water-bearing scCO2 as the subsurface working fluid. While the thermal-hydraulic performance of CPG systems has been extensively studied, their chemical behavior remains largely unexplored due to a lack of field and experimental observations. In this study, we address this knowledge gap by investigating the chemical performance of CPG systems through core-scale laboratory experiments. We conducted batch reactions on rock specimens from the Muschelkalk and Gipskeuper formations in Switzerland, subjecting them to interactions with wet scCO2 under reservoir conditions (~35 MPa, 150 °C) for approximately 500 hours. High-resolution techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray computed tomography (XRCT), and stable isotope analysis, were employed to characterize the evolution of petrophysical properties, morphology, and mineralogical composition. Furthermore, we analyzed fluid effluents using inductively coupled plasma optical emission spectroscopy (ICP-OES) to gain insights into ion transport processes associated with dissolution reactions. Our results indicate that fluid-mineral interactions involving CO2-rich supercritical fluids are less severe than those caused by aqueous solutions. Nonetheless, the existence of dissolved ions in the wet CO2 samples is clear evidence of ion dissociation caused by the gaseous phase that warrants further investigation. This experimental investigation provides critical insights into fluid-mineral interactions involving CO2-rich fluids and represents a crucial step in ensuring the long-term security and technical feasibility of deploying global CCS and CO2-based geothermal energy.
2.
1.
Asnin, S N, M Nnko, S Josephat, A Mahecha, E Mshiu, G Bertotti, and M Brehme, Fluid Flow Modeling using Geochemistry to Characterize the Songwe Medium Temperature Geothermal -Tanzania, EGU General Assembly Conference Abstracts , EGU21-9766, 2021.
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THESES
1.
Brehme, M., The role of fault zones on structure, operation and prospects of geothermal reservoirs-A case study in Lahendong, Indonesia, Dissertation, pp., 2015.