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The exploration of novel geothermal systems, particularly those promising for electrical power generation, plays a fundamental role in incorporating new renewable sources into the energy matrix. Geothermal systems associated with volcanic calderas are considered ideal targets for exploration. This study focuses on the geochemical features of fluids from the Cerro Galán hydrothermal system, which is hosted within a major resurgent caldera with >3.5 Myr of magmatic evolution situated on the Southern Puna (Central Volcanic Zone of the Andes, NW Argentina). The main aim is constructing the first geochemical conceptual model and provide information on the geothermal potential of this interesting resource. The main hydrothermal reservoir consists of a Na–Cl aquifer with estimated temperatures up to 187 °C at depth. This reservoir is likely hosted within the fractured pre-caldera basement rocks, mainly including Miocene-Pliocene volcanic rocks and Proterozoic-Cambrian igneous and metamorphic rocks. The confinement of the deep reservoir is attributed to the deposits of the Toconquis Group and Cueva Negra Ignimbrite, along with the basal section of the Cerro Galán Ignimbrite, which exhibit low permeability due to hydrothermal alteration. The presence of a phreatic explosion crater near one of the hot spring-rich areas is likely indicating past over-pressurization of the hydrothermal aquifer, resulting from efficient sealing. Furthermore, the absence of anomalous soil CO2 flux values on the top of the reservoir, except where the thermal spring discharges are located, can be explained by an effective cap-rock layer. Deep circulation of meteoric water, enriched with atmospheric gases, receives inputs of magmatic fluids (∼11% of primordial helium), leading to the development of the hydrothermal Na–Cl aquifer. However, this deep fluid contribution might be underestimated due to significant crustal assimilation (up to 50%) involved in the magma genesis of the Cerro Galán Vol

El texto completo de este trabajo no se encuentra disponible por no haber sido facilitado aún por su autor, por restricciones de copyright, o por no existir una versión digital, El Chichón is the northernmost and youngest volcano of the modern Chiapanecan volcanic arc and is responsible for the deadliest volcanic disaster in Mexico's modern history. Forty years after the eruption, there are still uncertainties in the subsurface architecture of the volcano and its basement. Based on this, we performed aeromagnetic data analyses using reduction–transformation techniques, spectral analysis, and forward modeling to delineate the magnetic rock–strata and to image the boundaries of the magmatic reservoir or regions of molten rock. Results show that the magnetic alignments identified correlate well with the local geological features. Our preferred interpretation of the estimated Curie point depth is as a region of mush composed of crystals and molten rock below the volcano (4.77 km), depicting the transitional sector to a deeper magma reservoir. We compute values of 101.57 °C km−1 and 253 mW⋅m−2 for the geothermal gradient and conductive heat flux, respectively. In addition, we identify two complementary aquifer formations representing the shallow−local and deeper−regional aquifer units using geomorphology, topographic, and stratigraphic characteristics. The magnetic anomalies analyzed and the identification of aquifer units in this study provide new detailed information about the geological, geophysical, and hydrogeological conceptual models of the El Chichón geothermal system., Consejo Nacional de Ciencia y Tecnología, CONACYT, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Induced seismicity is a limiting factor for the development of Enhanced Geothermal Systems (EGS). Its causal mechanisms are not fully understood, especially those of post-injection seismicity. To better understand the mechanisms that induced seismicity in the controversial case of the Basel EGS (Switzerland), we perform coupled hydro-mechanical simulation of the plastic response of a discrete pre-existing fault network built on the basis of the monitored seismicity. Simulation results show that the faults located in the vicinity of the injection well fail during injection mainly triggered by pore pressure buildup. Poroelastic stressing, which may be stabilizing or destabilizing depending on the fault orientation, reaches further than pressure diffusion, having a greater effect on distant faults. After injection stops, poroelastic stress relaxation leads to the immediate rupture of previously stabilized faults. Shear-slip stress transfer, which also contributes to post-injection reactivation of distant faults, is enhanced in faults with slip-induced friction weakening.

Harvesting geothermal energy often leads to a pressure drop in reservoirs, decreasing their profitability and promoting the formation of steam caps. While steam caps are valuable energy resources, they also alter the reservoir thermodynamics. Accurately measuring the steam fraction in reservoirs is essential for both operational and economic perspectives. However, steam content estimations are very limited both in space and time since current methods rely on direct measurements within production wells. Besides, these estimations normally present large uncertainties. Here, we present a pioneering method for indirectly sampling the steam content in the subsurface using the ever-present seismic background noise. We observe a consistent annual velocity drop in the Hengill geothermal field (Iceland) and establish a correlation between the velocity drop and steam buildup using in-situ borehole data. This application opens new avenues to track the evolution of any gas reservoir in the crust with a surface-based and cost-effective method.

In 2006 a mud volcano eruption took place in Sidoarjo area about 20 km South of Surabaya, the capital city of East Java Province, Indonesia. The eruption caused heavy environmental impact due to the large amount of mud erupted. There were controversial opinions about the generation of the eruption. The first opinion suspected the oil exploration well drilled in the area as the prime trigger. In contrary, the second opinion pointed out the role of earthquake and the existence of Watukosek fault extending in the area. The present study aims to reveal the subsurface structural characteristics of the area including the confirmation of the existence of Watukosek fault which might be contributive to the settlement of the controvercy.. The methods applied in this study are surface conventional data collections and subsurface seismic surveys. The results showed that the eruption was generated and controlled by the reactivation of Watukosek fault which gave a passage for mud to pierce to the surface. The fault also connected the heat source of Penanggungan-Arjuno Welirang and the mud eruption system. It was concluded that the Sidoarjo mud eruption was a geothermal system occurred in clastic materials. The specific phenomenon was the geyser type of mud eruption rarely found in sedimentary host rocks.

In 2006 a mud volcano eruption took place in Sidoarjo area about 20 km South of Surabaya, the capital city of East Java Province, Indonesia. The eruption caused heavy environmental impact due to the large amount of mud erupted. There were controversial opinions about the generation of the eruption. The first opinion suspected the oil exploration well drilled in the area as the prime trigger. In contrary, the second opinion pointed out the role of earthquake and the existence of Watukosek fault extending in the area. The present study aims to reveal the subsurface structural characteristics of the area including the confirmation of the existence of Watukosek fault which might be contributive to the settlement of the controvercy.. The methods applied in this study are surface conventional data collections and subsurface seismic surveys. The results showed that the eruption was generated and controlled by the reactivation of Watukosek fault which gave a passage for mud to pierce to the surface. The fault also connected the heat source of Penanggungan-Arjuno Welirang and the mud eruption system. It was concluded that the Sidoarjo mud eruption was a geothermal system occurred in clastic materials. The specific phenomenon was the geyser type of mud eruption rarely found in sedimentary host rocks.

These days, the number of geothermal explorations is being increased to obtain a greater new potential of geothermal energy. One of the methods that is often used is magnetotelluric (MT). By MT, the components of a geothermal system can be delineated based on the resistivity values. This research’s main purpose is MT data modelling in 1 D and 2 D to delineate the geothermal system in the research area. There are 18 point of soundings, with a distance of about 1 – 3 km for each point. Bostick Transformation is used in 1 D modelling while Non-Linear Conjugate Gradient inversion is used as 2 D modelling with L – curve analysis as a method to obtain an optimal value of regularization parameter. Based on the analysis of 1 and 2 D models, the caprock zone was identified with a resistivity value of < 50 Ωm at a depth of 500 m with a thickness of about 250 m. The reservoir zone was identified with a resistivity value range of (50 – 100) Ωm located at a depth of 1000 with a thickness of about 500 m. Also, fault structures have been identified at the center of the research area. The regularization parameter used for the 2 D modelling is 5, which has obtained RMS values of 2.25% and 2.21% for each line.

These days, the number of geothermal explorations is being increased to obtain a greater new potential of geothermal energy. One of the methods that is often used is magnetotelluric (MT). By MT, the components of a geothermal system can be delineated based on the resistivity values. This research’s main purpose is MT data modelling in 1 D and 2 D to delineate the geothermal system in the research area. There are 18 point of soundings, with a distance of about 1 – 3 km for each point. Bostick Transformation is used in 1 D modelling while Non-Linear Conjugate Gradient inversion is used as 2 D modelling with L – curve analysis as a method to obtain an optimal value of regularization parameter. Based on the analysis of 1 and 2 D models, the caprock zone was identified with a resistivity value of < 50 Ωm at a depth of 500 m with a thickness of about 250 m. The reservoir zone was identified with a resistivity value range of (50 – 100) Ωm located at a depth of 1000 with a thickness of about 500 m. Also, fault structures have been identified at the center of the research area. The regularization parameter used for the 2 D modelling is 5, which has obtained RMS values of 2.25% and 2.21% for each line.

In 2017 the National Power Company in Iceland, Landsvirkjun, started the operation of a geother- mal power plant in Theistareykir (Northeastern Iceland). The plant’s operation requires extraction, circulation, and injection of the geothermal fluids to produce energy. These processes depend on the existing fracture network of the reservoir. Therefore, geothermal energy exploitation requires knowledge of underground structures to identify potential fluid flow pathways. These are, in many cases, evidenced by the local seismicity. In this context, the GFZ German Research Center for Geo- sciences and Landsvirkjun chose this site for deploying a dense network of fifteen seismic broadband stations to monitor and characterize the field’s seismicity. The data coming from this very dense network allows us to implement and test an optimized processing scheme to perform a detailed analysis of the local seismicity. This study’s primary goal is to implement an efficient and reliable scheme to characterize the local seismicity of the Theistareykir geothermal field using the collected high-resolution seismic data from the dense network. I used several traditional earthquake seismology methods to detect, analyze, classify, and localize, repeating microseismic events. I first used a recursive STA/LTA algorithm to detect the local seismicity between January 1, 2018, until June 30, 2018. Using the detections, I manually reviewed and picked P- and S-phase arrival times. After an initial non- linear localization, I performed a correlation clustering analysis and identified two events with a high degree of waveform similarity. I corrected the picked phase arrivals using the cross-correlation coefficients of the events to a master trace. These events were relocated to improve their relative locations. Events of both clusters will be used in future studies for template-matching to detect and pick additional events within this period. The methodology applied here is meant as a guide to proce, MicroGraviMoTiS project, Applied Geophysics | IDEA League

In 2017 the National Power Company in Iceland, Landsvirkjun, started the operation of a geother- mal power plant in Theistareykir (Northeastern Iceland). The plant’s operation requires extraction, circulation, and injection of the geothermal fluids to produce energy. These processes depend on the existing fracture network of the reservoir. Therefore, geothermal energy exploitation requires knowledge of underground structures to identify potential fluid flow pathways. These are, in many cases, evidenced by the local seismicity. In this context, the GFZ German Research Center for Geo- sciences and Landsvirkjun chose this site for deploying a dense network of fifteen seismic broadband stations to monitor and characterize the field’s seismicity. The data coming from this very dense network allows us to implement and test an optimized processing scheme to perform a detailed analysis of the local seismicity. This study’s primary goal is to implement an efficient and reliable scheme to characterize the local seismicity of the Theistareykir geothermal field using the collected high-resolution seismic data from the dense network. I used several traditional earthquake seismology methods to detect, analyze, classify, and localize, repeating microseismic events. I first used a recursive STA/LTA algorithm to detect the local seismicity between January 1, 2018, until June 30, 2018. Using the detections, I manually reviewed and picked P- and S-phase arrival times. After an initial non- linear localization, I performed a correlation clustering analysis and identified two events with a high degree of waveform similarity. I corrected the picked phase arrivals using the cross-correlation coefficients of the events to a master trace. These events were relocated to improve their relative locations. Events of both clusters will be used in future studies for template-matching to detect and pick additional events within this period. The methodology applied here is meant as a guide to proce, MicroGraviMoTiS project, Applied Geophysics | IDEA League

The subsurface geological conditions of a geothermal system are vital objects to be considered in geothermal exploration. The Magnetotellurics survey was conducted to explore for geothermal potential in Pantar Island. This is to achieve deeper penetration compared to our previous study that adopted resistivity method to determine reservoir zones based on rock resistivity models. The difference in rock resistivity in geothermal systems provides subsurface geological information in the form of low resistivity that associated the clay cap zones (high conductive), the medium resistivity zones associated with the reservoir zones, and high resistivity associated with a heat source. The results of 2D and 3D models from MT data show that the low resistivity value (<20Ωm) as a clay cover zones, this layer from the surface to -1000 meters. Medium resistivity values ​​(20-100 Ωm) starting from depths -1000 meters to -2000 meters associated with reservoirs zones, high resistivity values (> 200 Ωm) starting from depths of -2000 meters are considered as heat source from the Pantar geothermal system.

The subsurface geological conditions of a geothermal system are vital objects to be considered in geothermal exploration. The Magnetotellurics survey was conducted to explore for geothermal potential in Pantar Island. This is to achieve deeper penetration compared to our previous study that adopted resistivity method to determine reservoir zones based on rock resistivity models. The difference in rock resistivity in geothermal systems provides subsurface geological information in the form of low resistivity that associated the clay cap zones (high conductive), the medium resistivity zones associated with the reservoir zones, and high resistivity associated with a heat source. The results of 2D and 3D models from MT data show that the low resistivity value (<20Ωm) as a clay cover zones, this layer from the surface to -1000 meters. Medium resistivity values ​​(20-100 Ωm) starting from depths -1000 meters to -2000 meters associated with reservoirs zones, high resistivity values (> 200 Ωm) starting from depths of -2000 meters are considered as heat source from the Pantar geothermal system.

This study investigated the three possible main causes of injectivity reduction in geothermal wells (suspended solids, scaling, biological activity). That has been done by obtaining water samples at three operating geothermal doublet locations in the Netherlands. This paper contains new geothermal data and the interpretation of them. At the moment, injectivity reduction is the biggest and least understood issue in geothermal projects in the Netherlands. Investigating this problem is valuable for current and future geothermal injectors and essential for the upscaling of geothermal energy in the Netherlands.The three locations differ from each other in several aspects (reservoir, surface facilities, chemicals in use, injectivity reduction), which yields a good comparison. Water samples were taken at different moments in time, on different points in the geothermal systems and for different purposes: TSS, chemical composition and ATP concentrations. The data is obtained in the laboratory and used for scale analysis (using the Stream Analyzer software from OLI Studio®) and microbial kill tests to determine the influences on growth. Scientific quality and data reliability are guaranteed by multiple pre-experiments (e.g. to verify sterility of sample bottles) and extra measurements (e.g. duplo samples, oxygen concentrations). It has been found that TSS is reduced through the systems by filters (from 35-55 mg/L in production water to <8-16 mg/L in injection water). Also, scales can potentially form (calcite before- and barite after the heat exchanger). Furthermore, biological activity in the water is initially low, but can grow over time to high levels (>500.000 microbial equivalents). Microbial growth is site-specific and correlatable to injectivity reduction. When there is microbial growth, corrosion inhibitor (CI) enhances this growth. Scale formation is possible, but has a limited likelyhood to cause significant injectivity problems. Furthermore, there is n, Petroleum Engineering and Geo-sciences

Geothermal energy is a renewable energy source on the raise. There is also considerable potential for development in the use of geothermal heat-pumps to tap geothermal energy close to the surface for the purposes of heating and cooling buildings. Underground heatexchangers are required for connecting the ground to a geothermal heat-pump. The choice of using an underground heat-exchanger depends on the individual installation parameters., La energía geotérmica es un recurso energético en alza. La calefacción y refrigeración de edificios mediante bombas de calor geotérmicas exigen, en muchos casos, la instalación de los intercambiadores de energía dentro de los sondeos o taladros ejecutados en el subsuelo. La función de un intercambiador de calor subterráneo es servir de vía de conexión entre el terreno, que es la fuente o el pozo de calor (en modo calefacción o en modo refrigeración), y el intercambiador de la bomba de calor geotérmica, donde se produce el intercambio de calor con el refrigerante de la misma. La elección del tipo de intercambiador y su dimensionamiento están supeditados a una serie de decisiones previas que son responsabilidad de la empresa contratista responsable de la climatización del edificio.

Geothermal energy is a renewable energy source on the raise. There is also considerable potential for development in the use of geothermal heat-pumps to tap geothermal energy close to the surface for the purposes of heating and cooling buildings. Underground heatexchangers are required for connecting the ground to a geothermal heat-pump. The choice of using an underground heat-exchanger depends on the individual installation parameters., La energía geotérmica es un recurso energético en alza. La calefacción y refrigeración de edificios mediante bombas de calor geotérmicas exigen, en muchos casos, la instalación de los intercambiadores de energía dentro de los sondeos o taladros ejecutados en el subsuelo. La función de un intercambiador de calor subterráneo es servir de vía de conexión entre el terreno, que es la fuente o el pozo de calor (en modo calefacción o en modo refrigeración), y el intercambiador de la bomba de calor geotérmica, donde se produce el intercambio de calor con el refrigerante de la misma. La elección del tipo de intercambiador y su dimensionamiento están supeditados a una serie de decisiones previas que son responsabilidad de la empresa contratista responsable de la climatización del edificio.

This study investigated the three possible main causes of injectivity reduction in geothermal wells (suspended solids, scaling, biological activity). That has been done by obtaining water samples at three operating geothermal doublet locations in the Netherlands. This paper contains new geothermal data and the interpretation of them. At the moment, injectivity reduction is the biggest and least understood issue in geothermal projects in the Netherlands. Investigating this problem is valuable for current and future geothermal injectors and essential for the upscaling of geothermal energy in the Netherlands.The three locations differ from each other in several aspects (reservoir, surface facilities, chemicals in use, injectivity reduction), which yields a good comparison. Water samples were taken at different moments in time, on different points in the geothermal systems and for different purposes: TSS, chemical composition and ATP concentrations. The data is obtained in the laboratory and used for scale analysis (using the Stream Analyzer software from OLI Studio®) and microbial kill tests to determine the influences on growth. Scientific quality and data reliability are guaranteed by multiple pre-experiments (e.g. to verify sterility of sample bottles) and extra measurements (e.g. duplo samples, oxygen concentrations). It has been found that TSS is reduced through the systems by filters (from 35-55 mg/L in production water to <8-16 mg/L in injection water). Also, scales can potentially form (calcite before- and barite after the heat exchanger). Furthermore, biological activity in the water is initially low, but can grow over time to high levels (>500.000 microbial equivalents). Microbial growth is site-specific and correlatable to injectivity reduction. When there is microbial growth, corrosion inhibitor (CI) enhances this growth. Scale formation is possible, but has a limited likelyhood to cause significant injectivity problems. Furthermore, there is n, Petroleum Engineering and Geo-sciences

Slab rollback results in the development of low-angle normal faults (detachments) and metamorphic core complexes (MCCs) in back-arc domains. Although the mechanical consequences of slab dynamics on lithospheric and crustal behaviors have already been studied, thermal effects have not been investigated yet. This study shows that slab rollback produces lithospheric-scale thermal perturbations intrinsically associated with emplacement of amagmatic high-enthalpy geothermal systems. Using a multi-scale numerical modeling approach, with lithospheric-scale 3-D thermo-mechanical models of subduction, and 2-D models of fluid flow at the scale of detachments, we demonstrate that subduction-induced extensional tectonics controls the genesis and distribution of crustal-scale thermal domes from the base of the crust, and the location of high-energy geothermal systems. We find that when slab tearing occurs, Moho temperatures can temporarily increase by up to 250 °C due to significant shear heating in the flowing upper mantle. Associated thermal anomalies (with characteristic width and spacing of tens and hundreds of km, for crustal and lithospheric scales, respectively) then migrate systematically toward the retreating trench. These thermal domes weaken the crust, localize deformation and enhance the development of crustal-scale detachments. These thermo-mechanical instabilities mimic genesis of high-temperature MCCs with migmatitic cores in the back-arc domain, such as those of the Menderes (western Anatolia, Turkey) and Larderello (southern Tuscany) provinces in the Mediterranean realm, and those in the Basin and Range (western United States), where detachments control the bulk of the heat transport. At the scale of MCCs, the bulk fluid flow pattern is controlled by topography-driven flow while buoyancy-driven flow dominates within the permeable detachments, focusing reservoir location of high-energy geothermal systems at shallow depth beneath the detachments.

The effect of conductive heat transfer recharge originating from the surrounding conduction dominated geothermal system on the geothermal reservoir lifetime has been reviewed during its development, by studying the effect of multiple reservoir and production parameters. A two dimensional (2D) finite volume implicit coupling strategy, using a direct solver method, is applied on a non-isothermal lumped-parameter model to simulate reservoir development over a period of 35 years. Two test cases are investigated, modelled after the low temperature geothermal fields of Middenmeer in The Netherlands and Soultz-sous-Forêts in France. Resulting produced thermal water temperature and thermal energy flow rate profiles are simulated with and without consideration of the geothermal system. A resolution of 200×200 equidistant structured cells is applied to cover an integrated (reservoir and surrounding) domain that extends 2 km vertically and 10 km horizontally. The reservoir domain extends 200 m vertically and 1 km horizontally, covered by a computational grid resolution of 20×20. Sensitivity analysis show that this is the best resolution that can be applied without losing simulator stability and accuracy. Results show that the conductive heat transfer recharge originating from the surrounding geothermal system has a significant effect on reservoir lifetime by reducing temperatures after thermal drawdown up to 26.5% in the first test case and up to %22.6 in the second test case. In addition, it lead to an increase in the average annual thermal energy production, up to %12.5 and %14.3 respectively. The consideration of the conductive recharge from the surrounding domain shows a significantly increased lifetime estimate for low temperature geothermal reservoirs. Furthermore, permeability, rock thermal conductivity and (re-)injection temperature are the reservoir and production parameters that can greatly influence the reservoir lifetime., Applied Earth Sciences

The effect of conductive heat transfer recharge originating from the surrounding conduction dominated geothermal system on the geothermal reservoir lifetime has been reviewed during its development, by studying the effect of multiple reservoir and production parameters. A two dimensional (2D) finite volume implicit coupling strategy, using a direct solver method, is applied on a non-isothermal lumped-parameter model to simulate reservoir development over a period of 35 years. Two test cases are investigated, modelled after the low temperature geothermal fields of Middenmeer in The Netherlands and Soultz-sous-Forêts in France. Resulting produced thermal water temperature and thermal energy flow rate profiles are simulated with and without consideration of the geothermal system. A resolution of 200×200 equidistant structured cells is applied to cover an integrated (reservoir and surrounding) domain that extends 2 km vertically and 10 km horizontally. The reservoir domain extends 200 m vertically and 1 km horizontally, covered by a computational grid resolution of 20×20. Sensitivity analysis show that this is the best resolution that can be applied without losing simulator stability and accuracy. Results show that the conductive heat transfer recharge originating from the surrounding geothermal system has a significant effect on reservoir lifetime by reducing temperatures after thermal drawdown up to 26.5% in the first test case and up to %22.6 in the second test case. In addition, it lead to an increase in the average annual thermal energy production, up to %12.5 and %14.3 respectively. The consideration of the conductive recharge from the surrounding domain shows a significantly increased lifetime estimate for low temperature geothermal reservoirs. Furthermore, permeability, rock thermal conductivity and (re-)injection temperature are the reservoir and production parameters that can greatly influence the reservoir lifetime., Applied Earth Sciences

Rapporten handlar om att jämföra fyra olika värmesystem med varandra. Dessa värmesystem är bergvärmesystem, sjövärmesystem, markvärmesystem och akvifersystem. Strukturen på rapporten ser ut på följande: Först beskrivs varje systemför sig, alltså hur hela systemet fungerar och sedan beskrivs nackdelar samt fördelar för varje system. Vid val av rätt värmesystem är det olika för olika villor eftersom alla har olika förutsättningar. Vid diskussion jämförs dessa fyra värmesystem med varandra utifrån just dessa förutsättningar. De förutsättningar som jämförs med varandra om de olika systemen går att hitta under rubriken målformulering längre fram., This rapport is about evaluating four different heating systems. These systems are first, each system is described, how it works and then pros and cons with each system. Choosing the right heating system is different for different buildings since they all have different conditions. In the discussion these four systems are compared to each other considering all these conditions. The Conditions examined can be found in the beginning of the report.

Rapporten handlar om att jämföra fyra olika värmesystem med varandra. Dessa värmesystem är bergvärmesystem, sjövärmesystem, markvärmesystem och akvifersystem. Strukturen på rapporten ser ut på följande: Först beskrivs varje systemför sig, alltså hur hela systemet fungerar och sedan beskrivs nackdelar samt fördelar för varje system. Vid val av rätt värmesystem är det olika för olika villor eftersom alla har olika förutsättningar. Vid diskussion jämförs dessa fyra värmesystem med varandra utifrån just dessa förutsättningar. De förutsättningar som jämförs med varandra om de olika systemen går att hitta under rubriken målformulering längre fram., This rapport is about evaluating four different heating systems. These systems are first, each system is described, how it works and then pros and cons with each system. Choosing the right heating system is different for different buildings since they all have different conditions. In the discussion these four systems are compared to each other considering all these conditions. The Conditions examined can be found in the beginning of the report.

U radu su proucavani hidrogeotermalni resursi na podrucju hidrogeološkog rejona Srpsko kristalasto jezgro. Podlogu istraživanja cine podaci ranijih geoloških, hidrogeoloških i geofizickih istraživanja, dok su za potrebe ove disertacije uraene nove detaljne hemijske analize voda (terenski su odreeni pH i elektroprovodljivost Ep, laboratorijski je odreeno 69 elemenata), izotopske analize (18O, 2H i 3H) i odreena je radioaktivnost voda (alfa, beta, 222Rn i 226Ra). Na osnovu ovih podataka definisani su: tip i svojstva voda, zona prihranjivanja, dubina zaleganja podzemnih voda, maksimalna ocekivana temperatura rezervoara, zasicenje vode mineralima, korozivna i inkrustrativna svojstva vode, radiogena toplota, geotermalni gradijenti, geotermalni potencijal, proracunato je trenutno i potencijalno korišcenje geotermalne energije, i definisani su hidrogeotermalni sistemi Srpskog kristalastog jezgra. Srpsko kristalasto jezgo je sacinjeno od kristalastih škriljaca koji su probijeni paleozojskim (bujanovacki) do tercijarnim granitoidima (surdulicki, jastrebacki) i andezitima (lecki andezitski masiv). U okviru ovog hidrogeološkog rejona nalaze se znacajnije pojave termalnih voda u Srbiji, pa su i lokaliteti na kojima se ove vode pojavljuju dobili status banja: Prolom Banja, Ribarska Banja, Sijarinska Banja, Vranjska Banja i Bujanovacka Banja, dok su pojave termalnih voda registrovane i na podrucju sela Vica i sela Tulare. Hidrogeotermalne sisteme Srpskog kristalastog jezgra karakteriše konvektivno strujanje podzemne vode. Ukupno procenjene kolicine hidrogeotermalnih resursa, odnosno termalnih voda iznose 186 l/s..., The paper considers hydrogeothermal resources on hydrogeology region Serbian crystalline core. Study is based on previously performed geological, hydrogeological and geophysical research, while the detailed chemical analyses of waters (field measurements of pH and Ep, laboratory analyses of 69 elements), isotopic analysis (18O, 2H i 3H) and water radioactivity (alfa, beta, 222Rn i 226Ra) present new data used in this study. Based on this new data, the following parameters have been defined: type and properties of waters, recharge zone, reservoir depths, maximal expected reservoir temperature, mineral saturation of waters, corrosive and scaling properties of waters, radiogenic heat, geothermal gradients and geothermal potential. Current and potential usage of geothermal energy has been calculated, and geothermal systems of Serbian crystalline core have been defined. Serbian crystalline core consists of crystal schist which are pierced with Paleozoic (bujanovacki) to Tertiary (surdulicki, jastrebacki) granitoids and andesits (lece massif). Within this hydrogeologic region significant occurrences of Serbian thermal waters are present, and the sites themselves are generally referred to as spas: Prolom Banja, Ribarska Banja, Sijarinska Banja, Vranjska Banja and Bujanovacka Banja, as well as the occurrence of thermal waters in the area of the villages Vica and Tulare. All hydrogeotermal systems of Serbian crystalline core are characterized by convective flow of groundwater. Total estimated outflow of hydrogeothermal recourses, respectively thermal waters is 186 l/s...

Numerous volcanoes, hot springs, fumaroles, and geothermal wells occur in the Pacific region of Latin America. These systems are characterized by high As concentrations and other typical geothermal elements such as Li and B. This paper presents a review of the available data on As concentrations in geothermal systems and their surficial discharges and As data on volcanic gases of Latin America. Data for geothermal systems in Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Ecuador, Bolivia, and Chile are presented. Two sources of As can be recognized in the investigated sites: Arsenic partitioned into volcanic gases and emitted in plumes and fumaroles, and arsenic in rocks of volcanic edifices that are leached by groundwaters enriched in volcanic gases. Water containing the most elevated concentrations of As are mature Ma-Cl fluids with relatively low sulfate content and As concentrations reaching up to 73.6 mg L-1 (Los Humeros geothermal field in Mexico), but more commonly ranging from a few mg L-1 to tens of mg L-1. Fluids derived from Na-Cl enriched waters formed through evaporation and condensation at shallower depths have As levels of only a few mu g L-1. Mixing of Na-Cl waters with shallower meteoric waters results in low to intermediate As concentrations (up to a few mg L-1). After the waters are discharged at the ground surface, As(III) oxidizes to As(V) and attenuation of As concentration can occur due to sorption and co-precipitation processes with iron minerals and organic matter present in sediments. Understanding the mechanisms of As enrichment in geothermal waters and their fate upon mixing with shallower groundwater and surface waters is important for the protection of water resources in Latin America., QC 20120924

Se presenta un estudio comparativo del cálculo de las características del fluido de yacimiento de diez pozos productores de los campos geotérmicos Los Azufres, Los Humeros y Cerro Prieto, utilizando dos programas de cómputo, GeoChem (GeoSys.Chem) y WATCH. GeoSys.Chem calcula la temperatura y la fracción de vapor del yacimiento a través de la geotermometría de cuarzo y asumiendo conservación de la entalpía, mientras que la temperatura promedio de geotermómetros de cuarzo y Na/K se emplea en WATCH. WATCH también calcula la fracción de vapor mediante la conservación de la entalpía. Ambos programas utilizan la conservación de alcalinidad (es decir, el balance de protones) para los cálculos de pH. La diferencia en temperatura (presión) provoca efectos considerables en las características del fluido de yacimiento geotérmico calculadas para pozos de alta entalpía, así como fracción de vapor negativa (o cercana a cero) para pozos de baja entalpía. La alta concentración calculada de CO2 en el vapor secundario liberado en la atmósfera en el vertedero (hasta 11.719 mmol/kg) sugiere que el análisis de las especies carbónicas en las aguas termales es crucial. En la ausencia de análisis de buena calidad de las especies carbónicas, se sugiere tener en cuenta el CO2 de la muestra de vapor en el separador y la concentración total de las especies carbónicas disueltas en la muestra de agua (es decir, sin tener en cuenta la liberación de CO2 en la atmósfera de vapor en el vertedero) para los cálculos de las composiciones de fluidos en los yacimientos geotérmicos., A comparative study of the reservoir fluid characteristics calculation of ten production wells of Los Azufres, Los Humeros and Cerro Prieto geothermal fields using two computer codes GeoChem (GeoSys.Chem) and WATCH is presented. GeoSys.Chem estimates the reservoir temperature and vapor fraction through quartz geothermometry and assuming enthalpy conservation, while the average temperature of quartz and Na/K geothermometers is employed in WATCH and vapor fraction is also calculated through enthalpy conservation. Both programs use the conservation of alkalinity (i.e., proton balance) for pH calculations. The difference in temperature (pressure) causes considerable effects on the calculated geothermal reservoir fluid characteristics of high enthalpy wells and negative (or near to zero) vapor fraction for low enthalpy wells. The calculated high concentration of CO2 in the secondary vapor discharged in the atmosphere at the weir box (up to 11,719 mmole/kg) suggests that the analysis of carbonic species in the geothermal waters is crucial. In the absence of good quality analysis of carbonic species it is suggested to consider the CO2 in the vapor sample at the separator and the total dissolved carbonic species concentration in the water sample (i.e., without considering the liberation of CO2 in the atmospheric vapor at the weir box) for the calculation of geothermal reservoir fluid composition.

Se presenta un estudio comparativo del cálculo de las características del fluido de yacimiento de diez pozos productores de los campos geotérmicos Los Azufres, Los Humeros y Cerro Prieto, utilizando dos programas de cómputo, GeoChem (GeoSys.Chem) y WATCH. GeoSys.Chem calcula la temperatura y la fracción de vapor del yacimiento a través de la geotermometría de cuarzo y asumiendo conservación de la entalpía, mientras que la temperatura promedio de geotermómetros de cuarzo y Na/K se emplea en WATCH. WATCH también calcula la fracción de vapor mediante la conservación de la entalpía. Ambos programas utilizan la conservación de alcalinidad (es decir, el balance de protones) para los cálculos de pH. La diferencia en temperatura (presión) provoca efectos considerables en las características del fluido de yacimiento geotérmico calculadas para pozos de alta entalpía, así como fracción de vapor negativa (o cercana a cero) para pozos de baja entalpía. La alta concentración calculada de CO2 en el vapor secundario liberado en la atmósfera en el vertedero (hasta 11.719 mmol/kg) sugiere que el análisis de las especies carbónicas en las aguas termales es crucial. En la ausencia de análisis de buena calidad de las especies carbónicas, se sugiere tener en cuenta el CO2 de la muestra de vapor en el separador y la concentración total de las especies carbónicas disueltas en la muestra de agua (es decir, sin tener en cuenta la liberación de CO2 en la atmósfera de vapor en el vertedero) para los cálculos de las composiciones de fluidos en los yacimientos geotérmicos., A comparative study of the reservoir fluid characteristics calculation of ten production wells of Los Azufres, Los Humeros and Cerro Prieto geothermal fields using two computer codes GeoChem (GeoSys.Chem) and WATCH is presented. GeoSys.Chem estimates the reservoir temperature and vapor fraction through quartz geothermometry and assuming enthalpy conservation, while the average temperature of quartz and Na/K geothermometers is employed in WATCH and vapor fraction is also calculated through enthalpy conservation. Both programs use the conservation of alkalinity (i.e., proton balance) for pH calculations. The difference in temperature (pressure) causes considerable effects on the calculated geothermal reservoir fluid characteristics of high enthalpy wells and negative (or near to zero) vapor fraction for low enthalpy wells. The calculated high concentration of CO2 in the secondary vapor discharged in the atmosphere at the weir box (up to 11,719 mmole/kg) suggests that the analysis of carbonic species in the geothermal waters is crucial. In the absence of good quality analysis of carbonic species it is suggested to consider the CO2 in the vapor sample at the separator and the total dissolved carbonic species concentration in the water sample (i.e., without considering the liberation of CO2 in the atmospheric vapor at the weir box) for the calculation of geothermal reservoir fluid composition.

[EN] This paper presents a method of subtracting the effect of atmospheric conditions from thermal response test (TRT) estimates by using data on the ambient air temperature. The method assesses effective ground thermal conductivity within 10% of the mean value from the test, depending on the time interval chosen for the analysis, whereas the estimated value can vary by a third if energy losses outside the borehole are neglected. Evaluating the same test data using the finite line-source (FLS) model gives lower values for the ground thermal conductivity than for the infinite line-source (ILS) model, whether or not heat dissipation to ambient air is assumed.

[EN] This paper presents a method of subtracting the effect of atmospheric conditions from thermal response test (TRT) estimates by using data on the ambient air temperature. The method assesses effective ground thermal conductivity within 10% of the mean value from the test, depending on the time interval chosen for the analysis, whereas the estimated value can vary by a third if energy losses outside the borehole are neglected. Evaluating the same test data using the finite line-source (FLS) model gives lower values for the ground thermal conductivity than for the infinite line-source (ILS) model, whether or not heat dissipation to ambient air is assumed.

[EN] This paper presents a method of subtracting the effect of atmospheric conditions from thermal response test (TRT) estimates by using data on the ambient air temperature. The method assesses effective ground thermal conductivity within 10% of the mean value from the test, depending on the time interval chosen for the analysis, whereas the estimated value can vary by a third if energy losses outside the borehole are neglected. Evaluating the same test data using the finite line-source (FLS) model gives lower values for the ground thermal conductivity than for the infinite line-source (ILS) model, whether or not heat dissipation to ambient air is assumed.

The siliceous sinter deposits of El Tatio geothermal field in northern Chile have been examined petrographically and mineralogically. These sinters consist of amorphous silica (opal-A) deposited around hot springs and geysers from nearly neutral, silica-saturated, sodium chloride waters. Water cooling and evaporation to dryness are the main processes that control the opal-A deposition in both subaqueous and subaerial settings, in close spatial relation to microbial communities. All fingerprints of organisms observed in the studied sinter samples represent microbes and suggest that the microbial community is moderately diverse (cyanobacteria, green bacteria, and diatoms). The most important ecological parameter is the temperature gradient, which is closely related to the observed depositional settings: 1) Geyser setting: water temperature = 70–86 °C (boiling point at El Tatio: 4200 m a.s.l.); coarse laminated sinter macrostructure with rapid local variations; biota comprises non-photosynthetic hyperthermophilic bacteria. 2) Splash areas around geysers: water temperature = 60–75 °C; laminated spicule and column macrostructure, locally forming cupolas (< 30 cm); predominant Synechococcus-like cyanobacteria. 3) Hot spring setting: water temperature = 40–60 °C; laminated spicules and columns and subspherical oncoids characterize the sinter macrostructure; filamentous cyanobacteria Phormidium and diatoms (e.g., Synedra sp.) are the most characteristic microbes. 4) Discharge environments: water temperature = 20–40 °C; sinter composed of laminated spicules and oncoids of varied shape; cyanobacterial mats of Phormidium and Calothrix and diatoms (e.g., Synedra sp.) are abundant. El Tatio is a natural laboratory of great interest because the sedimentary macrostructures and microtextures reflect the geological and biological processes involved in the primary deposition and early diagenesis of siliceous sinters.

On 2nd/3rd November 2002, a huge amount of gas, mainly composed of CO2, was suddenly released from the sea bottom off the coast of Panarea, producing a "crater" 20 by 10 meters wide and 7 meters deep. The gas output was estimated to be 109 1/d, two orders of magnitude higher than that measured in the 1980s. The anomalous degassing rate lasted for some weeks, slowly decreasing to an almost constant rate of about 4 × 107 1/d after two months. The geothermo-barometric estimations revealed an increase of both the temperature and pressure in the geothermal system feeding the sampled vents. The 3He/4He ratios were similar to those measured in nearby Stromboli. We have monitored the area for the last two decades, and based on our intensive and extensive geochemical measurements, have ascertained that the geothermal reservoir has lost its steady state. We maintain that a new magmatic input caused these phenomena.