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Response parameters in model settings of 4.a, 2.a, 4.b, 4.c, 4.d, 4.e, 4.f, 4.g and 4.h. a) Maximum outflowing water temperature, b) area of the thermal water reservoir (T > 30 • C) in proportion to the whole model domain and average water temperature, c) Péclet number plotted against horizontal hydraulic conductivity and d) location and horizontal extent of thermal water (T > 30 • C) discharge. Scenarios with recharge>1 m/yr are indicated by grey colour.
Source publication
Extensional domain type geothermal plays, as fertile targets for future resource development, consist of an orogen and an adjoining sedimentary basin of asymmetric physiographic and geologic setting. Preliminary geothermal potential, i.e. prospective geothermal regions, basin-scale flow patterns, heat transfer processes, temperature distribution an...
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Context 1
... portrayed very similar curves. The maximum temperature of discharging water (T max ) was not more than ~32 • C, except for one model geometry (4.g), where this value was a bit under 30 • C, i.e. without thermal water discharge. Water temperatures higher than 30 • C were mostly restricted to hydraulic conductivities of 2⋅10 6 to 5⋅10 5 m/s (Fig. 4.a). The portion of the thermal water reservoir (A% (T > 30 • C)) and average temperature (T av ) had the same plateau, starting at K = 2⋅10 8 m/s with values of ~79% of A% and ~ 58 • C of T av . There were only minor changes regarding A% and T av in the studied cases: their minima were ~ 4% and ~ 13 • C, respectively (Fig. 4.b). Minor ...
Context 2
... 2⋅10 6 to 5⋅10 5 m/s (Fig. 4.a). The portion of the thermal water reservoir (A% (T > 30 • C)) and average temperature (T av ) had the same plateau, starting at K = 2⋅10 8 m/s with values of ~79% of A% and ~ 58 • C of T av . There were only minor changes regarding A% and T av in the studied cases: their minima were ~ 4% and ~ 13 • C, respectively (Fig. 4.b). Minor differences could be observed in the values of Pe reflecting changes in the magnitude of groundwater flow due to water table variations: slightly higher Pe numbers were characteristic for cases (4.b, 4.e and 4.h) with higher water table maxima (1000 ft./304.8 m), i.e. groundwater flow was more intense. Otherwise, the critical ...
Context 3
... in the values of Pe reflecting changes in the magnitude of groundwater flow due to water table variations: slightly higher Pe numbers were characteristic for cases (4.b, 4.e and 4.h) with higher water table maxima (1000 ft./304.8 m), i.e. groundwater flow was more intense. Otherwise, the critical value of Pe = 1 was reached at K ≈ 5⋅10 8 m/s (Fig. 4.c). The location of thermal water discharge on the surface was controlled by the water table configuration. In cases (2.a and 4.d), where the regional slope was c' = 0.02 and the sine amplitude was a' ≈ 50 and 100 ft. (15.24 and 30.48 m), the thermal water discharged at the "regular" place of ~5800 m, i.e. at the discharge area of the ...
Context 4
... ~200 ft. (~60.96 m) (model 4.f), the location of discharge moved farther to ~8700 m because of local-scale variation of the water table and consequent shallow penetration depth of the flow paths. The width of the thermal water plume gradually decreased as the discharge location migrated along the x-axis and as the water table gradient decreased (Fig. ...
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Citations
... Míg az előbb említett Izlandnál a magma a közvetlen hőforrás, addig hazánkban a késő-miocéntől elvékonyodott földkéreg (22-30 km, Horváth et al. 2006;Horváth et al. 2015), tehető felelőssé az átlagot meghaladó hőáram sűrűségért: 30-120 mW/m 2 , átlagérték: 90 mW/m 2 (Lenkey-Mihályka-Paróczi 2021), szemben a kontinentális átlaggal, ami 65 mW/m 2 (Pollack-Hurter-Johnson 1993). Megállapítható, hogy a vázolt földtani körülmények mellett a hőmérsékletet nem csak a kőzetek hővezetése, hanem az áramló felszínalatti víz hőszállítása, a hőszigetelő képződmények jelenléte és a sűrűség különbségből adódó felhajtóerő is alakítja (Szijártó et al. 2021;Tóth-Galsa-Mádl-Szőnyi 2020 ). ...
Összefoglalás.
Magyarországon az energiaválság kapcsán előtérbe került a kedvező geotermikus adottságok kihasználásának szükségessége. A cikkben az európai geotermikus viszonyokból kiindulva mutatjuk be a hazai adottságokat, alkalmazható technológiákat. Az adottságok villamosáram-termelésre csak sporadikusan, magas kockázatok és technológiai fejlesztések mellett alkalmazhatók. Ugyanakkor az ország szinte teljes területén van lehetőség sekély geotermikus és hidrotermás készletek, valamint a hulladékhő további hasznosítására. A jövőben a termálvizek települési szintű, kaszkád rendszerű teljes körű hasznosítása lenne kívánatos. A fenntarthatóság kulcsa a lefűtött termálvizek nagyarányú visszasajtolása. A felszín alatti térrész, a különböző fluidumok és a bennük rejlő nyersanyagok hasznosítása kutatást és új, komplex szemléletet igényel.
Summary.
The need to exploit the favourable geothermal potential has emerged in Hungary due to the war-induced energy crisis. In this paper, we present the geothermal conditions of Hungary with a European comparison. The elevated heat flux of the Pannonian Basin, thanks to the thinned lithosphere, provides beneficial conditions along with the thermal-bearing aquifers primarily for medium enthalpy resources. We detail the potential technologies applicable to exploit the various types of resources and the risks related to their utilisation. Although not all of the technologies can be applied everywhere in the country, our results show that shallow geothermal or hydrothermal utilisation is possible in the entire country, as well as the utilisation of waste heat from used water or natural springs. Assessing geological risks is a decision criterion in the project preparation phase: supporting the investment with lower geological risk leads to more successful projects and, simultaneously, helps to gain more knowledge about the geological formation. With high risks, Hungarian geothermal resources can only be used sporadically for electricity generation. Experience of ongoing international projects in enhanced geothermal systems should be gathered for the future use of deep basement resources. The main unconsidered potential in Hungary lies in the cascaded use of thermal water at the municipal level, which can be a key in constructing low-carbon district and space heating systems combined with agricultural use. The unsolved research-intensive issue of sustainable exploitation is the extensive reinjection of cooled thermal waters, which prevents the overuse of slowly renewable resources. Developing this sector in Hungary regarding conventional and combined innovative exploitation of the subsurface space requires research and new complex approaches.
... The elevation in the geothermal water discharge area may have exceeded the recharge elevation, leading to a phenomenon of "anti-gravity" in the study of the fault-controlled hydrothermal system in Kangding County (Wang et al., 2019). The water level in the discharge zone of geothermal water can be higher than the recharge level has also been confirmed in a modelling study of geothermal water transport in asymmetric basins (Tóth et al., 2020). The abnormal phenomenon that the water level in the discharge area is higher than that in the recharge area of the hydrothermal system indicates that, in addition to the gravity driving force, there is a new additional driving force that affects and even controls the discharge process of geothermal water. ...
... However, based on the numerical results, the water divides acted only as surface water/shallow groundwater divides because more regional conditions determine the deeper flow pattern. For that, a basin-scale evaluation is required, highlighting the importance of basin geometry and the asymmetry of driving forces [125]. ...
... The geothermal conditions could be more favourable (50-60 • C/km) around the foothills at the discharge zones and the occurrence of lukewarm springs [128][129][130]. The regions south of Lake Balaton (out of the current study area) could have higher geothermal potential [96,131] due to basin-scale hydrogeologic conditions [125]. ...
... This also explains why the groundwater contribution from the southern shore was not investigated. The absent or rather negligible amount of water coming from the hilly region south of Lake Balaton can be justified by the asymmetric groundwater flow pattern caused by different hydraulic head distributions on the two sides of the lake, revealed by basic-scale numerical simulation [125]. Even though the sublacustrine springs were sampled, their hydrochemical character was not analysed, only the gas content [15]. ...
The hummocky Balaton Highland is located in western Hungary and is part of the Transdanubian Mountains, the most extensive carbonate aquifer system in Hungary. The study region also encompasses Lake Balaton, the biggest lake in central Europe, which is to the south of Balaton Highland. The surface water–groundwater interaction in the Balaton Highland–Lake Balaton region and the groundwater contribution to Lake Balaton are revisited in this paper. Hydrostratigraphic classification was performed first; then, groundwater flow directions by hydraulic head distribution were analysed, and baseflow indices of surface watercourses were calculated. Regarding hydrochemical characterisation, general hydrochemical facies were identified, natural tracers of temperature, chloride and uranium were applied, and the stable isotopic composition of oxygen and hydrogen was determined. Finally, groundwater flow and heat transport were simulated in a 2D numerical model. A high level of hydraulic interaction was evidenced between surface water and groundwater and the sub-regions of Bakony Mountains, Balaton Highland and Lake Balaton by physical and chemical parameters, numerical simulation and groundwater-flow-related natural manifestations, revealing hydraulic continuity in the study region. Based on the results, the division of legislative water bodies can be reconsidered, especially that surface water and groundwater should be regarded as interconnected, and Lake Balaton can be considered a groundwater-dependent ecosystem in any water-use planning in the region.
... Regional basin-scale hydrology was generally characterized by gravity-driven flow and considered as steady state. The hierarchically and steadily developed nested flow systems of basin asymmetry [54] for W-E and S-N cross sections in the study area are presented in Figure 6. The groundwater flows from the west to the east and from the north to the south, which is correlated with the overall terrain gradient [55] and verified by the Tóth basin theory. ...
Mine water injection into deep formations is one of the effective approaches for reducing
the drainage from coal mines in the arid and semi-arid region of the Ordos basin, China. Many coal mines are attempting to execute the related projects. Under the influence of groundwater protection, the understanding of regional groundwater flow is becoming highly important to the mine water monitoring, whereas quite few academic research teams focus on the deep groundwater flow pattern by mine water injection. This paper reveals the spatial distribution of Liujiagou Formation that is in positive correlation with the terrain, and its local thickness is influenced by the dominant W-E and NE-SW directions of geological structures. Only a part of sandstone rocks consists of aquifers, the rest 61.9% of relatively dry rock provide the enhanced storage space and partial mudstone aquicludes decrease the possibility of the vertical leakage for mine water. The dynamic storage capacity is evaluated at 2.36 Mm3 per 1 km2 and over 25.10 billion m3 in this study area. Two hydrogeologic cross-sections of basin-scale identify the W-E and N-S regional groundwater flow directions, with the lower Yellow River catchment becoming the discharged region. The hierarchically and steadily nested flow systems containing coal mining claims are influenced by coal mining activity. The groundwater depression cone in a shallow coal measure aquifer is caused by mine water drainage whereas the groundwater mound in Liujiagou Formation is generated by mine water injection activity. The numerical simulation revealed that the groundwater head rebound is slightly decreased and will not recover to its initial baseline within 500 years due to its low porosity and permeability. This study elucidates the deep groundwater flow patterns induced by mine water injection and provides a practical methodology for the management and pollution monitoring of mine water injection activity.
... Goldscheider et al. (2010) published the first paper highlighting the significance of flow system approach in the understanding of the thermal water resources and related geochemical processes. However, the revealed discrepancy was only resolved by the conceptualization of Tóthian-type flow pattern for adjoint confined and unconfined basin-halves based on the joint interpretation of numerical flow and heat transport simulations (Fig. 1, Mádl-Szőnyi and Tóth 2015;Szijártó et al. 2019;Tóth et al. 2020). Based on these studies, we can identify those parts of the system where the carbonate rocks are unconfined or partially covered with siliciclastic sediments (i.e., semi-confined basin-half) and where intense meteoric water recharge takes place. ...
... Moreover, based on this concept, the potential locations of epigene and hypogene speleogenesis can be revealed. This geometry of two connected basin-halves of unconfined and confined carbonates, and the consequent heat distribution and flow pattern, the occurrence of springs and caves can be handled as a new adaptation of the Tóthian flow concept for carbonate sequences (Fig. 1, Tóth et al. 2020;Mádl-Szőnyi and Tóth 2015;Mádl-Szőnyi 2020). ...
... In this chapter, the remarkably diverse and rich literature of karst hydrogeology of Hungary was systematically introduced based on the regional groundwater flow concept adapted for adjoining confined and unconfined basin-halves of carbonate regions (Mádl-Szőnyi and Tóth 2015; Mádl-Szőnyi 2020; Tóth et al. 2020). Moving groundwater behaves as a geologic agent (Tóth 1999), therefore the discussed Hungarian karst systems and the consequent karst phenomena (springs, epigene, and hypogene caves) were interpreted as the manifestations of flowing groundwater. ...
The Hungarian karst regions with diverse geologic settings and hydrogeologic characteristics are presented and discussed in a basin-scale groundwater flow framework which is the adaptation of groundwater flow systems to carbonate regions and, thus, a novel approach in karst hydrogeology studies. Accordingly, a solid but comprehensive overview of the hydrogeologic environment (topography, climate, and geology), groundwater flow patterns and processes (flow systems and directions, hydrochemistry and temperature conditions), groundwater-related phenomena (springs and caves), and groundwater resources (direct and indirect use) is provided for the Aggtelek Karst, Bükk Mts., SW and NE Transdanubian Mts., Mecsek Mts., and Villány Mts. By the application of this concept, the asymmetric flow patterns, distribution of cold, lukewarm and thermal springs, heat accumulation and heat transport processes, mixing of meteoric and basinal and waters of local, intermediate and regional groundwater flow systems and potential locations of epigene and hypogene speleogenesis can be revealed and explained. The Hungarian karst areas reflect different properties but there are similarities regarding their hydrogeologic environment and flow systems, as well. Therefore, the local-scale karst features and peculiarities fit into a bigger, i.e., basin-scale, picture which can provide a sound base for regional hydrogeologic characterization of karstic carbonate areas.
... Geothermics is considered a promising field and continues to garner more research interest. Geothermics spans multiple sub-disciplines, namely, geology (Ngansom et al., 2019;Millett et al., 2020;Šafanda et al., 2020), tectonics (Carlino, 2018;Chicco et al., 2019;Hacıoğlu et al., 2020;Tzanis et al., 2020), geophysics Mazzoldi et al., 2020;Trainor-Guitton, 2020), and hydrogeology (Yurteri and Simsek, 2017;Maya et al., 2018;Tóth et al., 2020;Torresan et al., 2020). Scholars have explored and estimated the reserves of geothermal energy. ...
... The second quadrant is "geothermal water" and "enhanced geothermal system" enhanced geothermal systems. Both are widely distributed and have great resource potential and good application prospects (Agemar et al., 2014;Ma et al., 2017;Yurteri and Simsek, 2017;Lu, 2018;Catalan et al., 2019;Torresan et al., 2020;Tóth et al., 2020). However, they may not be well-developed due to scientific and technological limitations. ...
Geothermal energy is considered a renewable, clean, and environmentally friendly energy source. In addition, it is efficient and relatively cost effective. Therefore, the demand for the development and utilization of geothermal resources is increasing annually. To understand the current status and developments within the context of geothermal research, quantitative and qualitative analyses were carried out by combining two visualization software applications, namely, VOSviewer and CiteSpace; this analysis also entailed the secondary development of R language. The results showed that the USA, China, and Germany are the main contributors to geothermal research. We also found that geothermal research hot spots encompass five geothermal research clusters, such as renewable energy utilization, heat flow, numerical simulation, geochemistry, and groundwater. In addition, the strategic diagram and thematic structure revealed how geothermal research has evolved over time. Finally, the timeline view and burst term highlight the possible frontiers of geothermal power generation, enhanced geothermal systems, and ecological environment protection. These insights will provide scholars and policymakers with a systematic understanding of the current research and directions for future studies.
... The results of the coupled flux and heat modeling analyses are consistent with previous studies in other areas of the world. Groundwater flow on the basin scale is controlled by numerous factors: the configuration of the water table [35][36][37][40][41][42], the effects of temperature on fluid density and viscosity in heterogeneous anisotropic media [37,43], the effect of hydraulic conductivity contrasts and temperature boundaries [44], the three-dimensional flow field with the variations and areal distribution of heat affected by relief on the water table and permeability variations [37,45], advective heat transfer [29,30,42,45,46], temperature distributions for paleoflow systems [47,48], the modeling of heat as a groundwater tracer [49] and of large-scale flow [38], and the significance of basin asymmetry and geothermal assessments [36][37]50], among many others. ...
... The results of the coupled flux and heat modeling analyses are consistent with previous studies in other areas of the world. Groundwater flow on the basin scale is controlled by numerous factors: the configuration of the water table [35][36][37][40][41][42], the effects of temperature on fluid density and viscosity in heterogeneous anisotropic media [37,43], the effect of hydraulic conductivity contrasts and temperature boundaries [44], the three-dimensional flow field with the variations and areal distribution of heat affected by relief on the water table and permeability variations [37,45], advective heat transfer [29,30,42,45,46], temperature distributions for paleoflow systems [47,48], the modeling of heat as a groundwater tracer [49] and of large-scale flow [38], and the significance of basin asymmetry and geothermal assessments [36,37,50], among many others. ...
The Independence Basin is located in a semi-arid region of Mexico, delimited predominantly by volcanic mountains. Around 30 m3/s of water are extracted from regional aquifers mainly for agro-export activities, causing declines in the water table of up to 10 m/a, increased temperature and dissolved elements that are harmful to health and the environment. Regional groundwater coupled flow and heat transport under current conditions were studied on a basin-wide scale (7000 km2) using a three-dimensional finite-element model under steady-state conditions to provide support for water management decisions and transient modeling. Isothermal, forced and free thermal convection under existing hydrological conditions prior to pumping are analyzed. The results show that the interaction of topography-driven groundwater flow and buoyancy-driven free thermal convection are consistent with historical hydrological records, the characteristics of the water table, and thermal anomalies observed in the basin. The simulated groundwater recharge is near 7 ± 0.25 m3/s, a balance broken since the 1980s by extensive pumping. The results show the importance of considering the groundwater temperature, its transient response in the evolution of groundwater extraction, and the upward migration of a thermal front through the fractured aquifer that has increased risks for health and sustainability.
... Numerical flow modeling of steady-state and transient groundwater flow pathways and intensities provides the base for transport modeling of mass (conservative or reactive) and heat, and paleo flow system modeling. (ENeRAG examples for application:[24,25,[36][37][38][39].) (3) Mass or contaminant transport simulations can be used for instance in groundwater vulnerability assessment and Managed Aquifer Recharge (MAR) evaluation, whilst heat transport simulations can be applied for instance in geothermal (groundwater and bedrock) energy utilization.(ENeRAG examples for application:[25,36,[40][41][42][43].) (4) Paleo flow system modeling requires preliminary geodynamic and structural modeling, then complemented with mineralogical and lithogeochemical studies it can be used for target generation in mineral exploration (ENeRAG examples for application:[44,45].) (5) Use of stable, radioactive and radiogenic isotopes as environmental tracers, as well as stochastic and spatial statistical modeling can significantly improve the modeling results, such as groundwater vulnerability and mineral potential evaluation.(ENeRAG ...
The ‘Dynamic System Approach for Geofluids and their Resources’ was developed to
harmonize research and the sustainable exploration of geofluids (e.g., groundwater, geothermal and
hydrothermal fluids) and the related geo-resources (groundwater, geothermal energy and hydrothermal minerals). The conception is based on the basin-scale groundwater flow systems, which behave
as a geologic agent, mobilize, transport and deposit matter and heat, whilst it can be evaluated
quantitatively and in a distributed manner. Evaluation of these systems combined, for instance, with
numerical, stochastic and isotope methods can jointly manage all types of geofluids, the related resources and the environmental consequences of their exploration and utilization. This paper describes
the fundamental concepts of the approach and displays the proposed workflow and guidelines for
practical applications such as groundwater vulnerability assessment, managed aquifer recharge,
geothermal energy utilization, and the evaluation of hydrothermal mineral potential.
