Geothermal Systems

Andis Faza Fauzana (071001700016) I. Latar Belakang Setelah lapangan geothermal dikembangkan dan produksi telah dimulai, manajemen produksi dan operasi injeksi untuk menjaga power plant pada kapasitas penuh menjadi prioritas utama. Hal ini melibatkan multidisiplin ilmu seperti produksi, geokimia, teknik reservoir dan simulasi untuk menyatukan data produksi dan injeksi yang diukur dipermukaan dengan informasi sumur di bawah permukaan. Untuk memahami proses yang terjadi di reservoir, terkadang melibatkan geosains dari waktu ke waktu untuk melakukan survey microgravity dan ground deformation. Selain itu, akan dilakukan juga pemantauan korosi subsurface dan kerusakan casing. Semua informasi ini harus disatukan menjadi satu model yang dapat digunakan untuk memprediksi kapasitas produksi dan injeksi di masa depan dan untuk mengidentifikasi area yang perlu perbaikan untuk menjaga production plant pada kapasitas penuh. Hal ini dapat dilakukan dengan pembersihan sumur secara berkala untuk menghilangkan scale calcit atau memindahkan sumur injeksi untuk menghindari "return fluids" diantara sumur produksi dan injeksi. Beberapa data yang akan sering tersedia diantaranya adalah wellhead pressure (WHP), valve settings, aliran uap dan brine, aliran total (massa dan entalpi) dari separator, aliran injeksi dan suhu sumur dsb. Data lainnya dari pemantauan reservoir yang utama berupa tekanan sumur dan data lain yang

Comprehensive data on the chemical composition of reservoir rocks and geothermal brines from the geothermal well doublet Grob Sch€ onebeck (North German Basin) drilled into a Rotliegend sedimentary and Permo-Carboniferous volcanic rock reservoir were sampled over the past years. They were characterized with respect to their major and minor elemental composition including various isotope ratios. The study considered the impact of drilling and reservoir operations on fluid composition and aimed at determining fluiderock interactions to gain information on fluid origin and hydraulic pathways. The highly saline fluids (up to 265 g/L TDS) show d 18 O and dD of water (2.7e5.6 and À3.1e15, respectively) as well as d 34 S of sulfate (3.6e5), and 87 Sr/ 86 Sr ratios (0.715e0.716) that resemble Rot-liegend brines from an area located around 200 km in the west (the Altmark). Halogen ratios indicated that brines developed predominantly by evaporation of meteoric water (primary brine) together with halite dissolution brine (secondary brine). Indication for mixing with Zechstein brine or with younger meteoric water was not found. No geochemical distinction was possible between fluids deriving from different rock formations (dacites or sedimentary rocks, respectively). This is due to the evolution of the sediments from the effusive rocks resulting in a similar mineralogical and chemical composition and due to a hydraulic connectivity between the two types of rock. This connection existed probably already before reservoir stimulation as indicated by a set of faults identified in the area that could connect the Rotliegend formation with both, the volcanic rocks and the lower units of the Zechstein. Additional geochemical indication for a hydraulic connectivity is given by (1) the very high heavy metal contents (mainly Cu and Pb) in fluids and scaling that derive from the volcanic rocks and were that were also found in increased amounts up at the Zechstein border (Kupferschiefer formation). (2) The 87 Sr/ 86 Sr isotope ratios of fluid samples correspond to the ratios determined for the sedimentary rocks indicating that initially the fluids developed in the sedimentary rocks and circulated later, when faults structures were created by tectonic events into the volcanic rocks.

ABSTRACT: El modelo conceptual geotérmico de baja entalpía propuesto en esta investigación se localiza en el Valle de Orosi, Paraíso, Cartago, el área de interés posee una extensión total de 30,86 km2. La geología local está compuesta por las formaciones: Pacacua, Peña Negra, Coris, Doán (Grupo V. Aguacate), Lavas del Miembro Paraíso (Formación Reventado), Intrusivos de Tapantí (Grupo Comagmático de Talamanca); y finalmente los depósitos recientes. La fuente de calor en el sistema se asocia con los Intrusivos de Tapantí, los cuales Denyer & Alvarado (2007), cartografían muy cerca del límite SW del área de estudio (< 2 km aproximadamente); y Alvarado & Gans (2012), les asignan una edad de 4,20 a 3,89+/-0,30 Ma. En 3 análisis petrográficos al S del área de estudio (cercanos a la fuente de calor), se aprecian paragénesis mineralógicas secundarias de abundante clorita azul (pennina) y epidota + leucoxeno + cuarzo fino, vinculadas con temperaturas máximas >240 ºC, específicamente en las litologías de la Fm. Pacacua (basamento). Los estudios tectónicos basados en evidencias de campo, geomorfología y geofísica (32 anomalías), sugieren la existencia de 2 fallas regionales: Falla Orosi (rumbo SE-NW), y Falla Navarro (NE-SW), también de 28 fallas locales de importancia. Del total de fallas propuestas al menos 11 tienen relación directa con la ubicación de sitios con aguas termales. La existencia y ubicación de los sitios con aguas termales se relacionan con la permeabilidad secundaria producto del sistema tectónico preponderante de la Falla Orosi y de las zonas de interacción de este sistema con las fallas orientadas al N-S y NE-SW principalmente. Se investigaron 81 muestras de agua provenientes de 42 sitios visitados, hallando presencia de aguas termales en los sitios: BE-A11, BE-Z21, Pozo BE, BE-27, BE-28 y BE_38-39. Las muestras del sitio BE-28 (Finca Chúcaras), sugieren una mayor estabilidad hidrogeoquímica y térmica profunda (150 ºC aprox.), siendo el sector del área de estudio con el mayor potencial teórico para la exploración o aprovechamiento de recursos geotérmicos de baja entalpía. En el modelo geotérmico conceptual las condiciones tectónicas favorecen la permeabilidad secundaria de los fluidos, iniciando en las montañas de la Cordillera de Talamanca al S y SW del valle, en la zona de captura de aguas meteóricas, las cuales posteriormente interactúan en profundidad con la fuente de calor y/o la roca caja calentada absorbiendo masa y temperatura, lo que origina un flujo caracterizado por aguas geotérmicas relativamente sulfatadas, menos evolucionadas, que ascienden al S y SW del área de estudio en los sitios con aguas termales: BE_38-39, BE-28 y BE-27 (cercanos a la fuente de calor). Además se presentan fluidos geotérmicos movilizados de forma compleja y restringida por el diaclasamiento predominante hacia las partes más distales del sistema (N del área de estudio), caracterizados por una mayor concentración de cloruro, siendo relativamente más evolucionados; y manifestándose en los sitios con agua termal: BE-A11, Pozo BE, BE-Z21 y no termal: BE-40 y BE-A13. No obstante este segundo grupo presenta una aparente mayor dilución o afectación por aguas superficiales dentro del sistema.tesis (Licenciatura) -- Universidad de Costa Rica. Escuela de Geología, 2014. Correo para contacto: isanac81@gmail.com

Renewable energy resources have gained relevance in countries worldwide as an alternative to diversify, in a more environmentally amicable manner, its energy matrix. However, even though the use of the resource might be considered as a step forward towards achieving sustainability, in terms of the power plant, the environmental impact its only one aspect. Economic and social aspects should be study altogether with the environmental ones so that a holistic sustainability assessment can be provided. It is important to bear in mind that even though the impact of renewable power plants might be considered beneficial for a global area (for instance, a country) it might not be for the area where it is located, thus the relevance of a sustainability assessment. In this article we will perform a sustainability assessment study using two ideal scenarios of geothermal power plants projects for comparison. A set of sustainability indicators will be presented taking into account important aspects of geothermal power plants construction and operation while integrating the sustainability criteria.

Menurut Kasbani, 2010 dan berdasarkan asosiasi terhadap tatanan geologinya, sistem panas bumi di Indonesia dapat dikelompokkan menjadi 3 jenis, yaitu : vulkanik, vulkano – tektonik dan Non-vulkanik. 1. Sistem panas bumi vulkanik Adalah sistem panas bumi yang berasosiasi dengan gunungapi api Kuarter yang umumnya terletak pada busur vulkanik Kuarter yang memanjang dari Sumatra, Jawa, Bali dan Nusa Tenggara, sebagian Maluku dan Sulawesi Utara. Pembentukan sistem panas bumi ini biasanya tersusun oleh batuan vulkanik menengah (andesit-basaltis) hingga asam dan umumnya memiliki karakteristik reservoir sekitar 1,5 km dengan temperature reservoir tinggi (~250-≤ 370°C). Pada daerah vulkanik aktif biasanya memiliki umur batuan yang relatif muda dengan kondisi temperature yang sangat tinggi dan kandungan gas magmatik besar. Ruang antar batuan (permeabilitas) relatif kecil karena factor aktivitas tektonik yang belum terlalu dominan dalam membentuk celah-celah / rekahan yang intensif sebagai batuan reservoir. Daerah vulkanik yang tidak aktif biasanya berumur relatif lebih tua dan telah mengalami aktivitas tektonik yang cukup kuat untuk membentuk permeabilitas batuan melalui rekahan dan celah yang intensif. Pada kondisi tersebut biasanya terbentuk temperatur menengah – tinggi dengan konsentrasi gas magmatik yang lebih sedikit. Sistem vulkanik dapat dikelompokkan lagi menjadi beberapa tipe, misal : system tubuh gunung api strato jika hanya terdiri dari satu gunungapi utama, sistem komplek gunung api jika terdiri dari beberapa gunungapi, sistem kaldera jika sudah terbentuk kaldera dan sebagainya. Gambar 1 adalah contoh tipe system komplek gunung api di lingkungan pulaupulau kecil seperti Pulau Weh, sedangkan Gambar 2 merupakan contoh tipe system komplek gunung api di lingkungan pulaupulau besar seperti di Pulau Jawa. Hal ini untuk menunjukkan bahwa tipe yang sama akan memberikan potensi yang jauh berbeda jika lingkungannya berbeda. Gambar 3 adalah salah satu contoh tipe sistem kaldera.

Geothermal is an alternative energy that improving in Indonesia and has great potential in Indonesia. But the problem is the lack of exploitation. So the goverment conduct intensive exploration to several area in Indonesia. One of the area that become focus in this exploration is East Manggarai, East Nusa Tenggara. East Manggarai is mostly consisted by volcanic rocks from young volcano such as Mt. Ranaka. This research is an early survey as the first step. The object in this research are hot springs as geothermal ground manifestation, they are Mapos, Wae Lareng, and Ulu Galung hot spring.

According to the research result, Mapos-Wae Lareng hot spring types are sulfate and bicarbonate while Ulu Galung hot spring type is sulphate. And if we see the reservoir, Mapos hot spring and Wae Lareng hot spring have the same reservoir. To support the geochemistry experiment on the hot waters,  research on Hg in the soil is conducted so we can achieve the potential speculative area. And if it combined with geothermometer data we will achieve that the geothermal speculative resources potential for Mapos-Wae Lareng is 57 Mwe and for Ulu Galung is 0,3 Mwe, which mean that Mapos-Wae Lareng area is more potential for further research than Ulu Galung.

Four of the nine potentially active volcanoes on the island of Dominica in the Lesser Antilles volcanic island arc have associated active volcanic-hydrothermal systems. Between 2000 and 2006 the gas and thermal waters from these systems were investigated to geochemically characterise the fluids, gain insight into the temperature and equilibrium state of the underlying reservoirs, and evaluate the feasibility of monitoring geothermal features as a volcano surveillance tool in Dominica. The geothermal gases are typical of those found in arc-type settings, with N2 excess and low amounts of He and Ar. The dry gas is dominated by CO2 (ranging from 492 to 993 mmol/mol), and has a hydrothermal signature with hydrogen sulphide as the main sulphurous gas. The waters are predominantly acid-sulphate (SO4 = 100–4200 mg/L, pH ≤ 4), and likely formed as a result of dilution of acidic gases in near surface oxygenated groundwater. Enrichment in both δ18O and δD with respect to the global meteoric water line (GMWL) confirms that the waters are of primarily meteoric origin, but have been affected by evaporation processes. Quartz geothermometers gave equilibrium temperatures of 83 °C–203 °C. These temperatures contrast with the higher equilibrium temperature ranges (170 °C–350 °C) obtained for the gases using the H2/Ar*–CH4/CO2 gas ratios plot, suggesting that the quartz geothermometers are affected by non-attainment of equilibrium. This may be a result of precipitation of the dissolved silica and/or dilution by relatively cold shallow aquifers of the thermal fluids. Generally, no significant variations in fluid gas chemistry of the hydrothermal systems were observed during the study period, and we propose that there were no changes in the state of volcanic activity in this period. One exception to this occurred in a feature known as the Boiling Lake, which underwent a month-long period of significant compositional, temperature and water level fluctuations ascribed to a drastic decrease of hydrothermal input related to a perturbation in the lake (probably seismically induced). This geochemical study is part of an ongoing monitoring programme of Dominica geothermal systems, aimed at establishing long-term geochemical observations for the purpose of volcano monitoring.► This research seeks to improve the understanding of hydrothermal systems associated with live volcanoes in Dominica. ► Fluid geochemistry is investigated to evaluate the feasibility of geothermal monitoring as a volcano surveillance tool. ► Chemical composition of the hydrothermal waters indicates a primarily meteoric origin, with minor magmatic component. ► A characteristic feature of the hydrothermal gases is their lack of deep originated gas compounds (HCl, HF, SO2). ► Dominance of a meteoric component suggests low magmatic fluid flux, or thick reservoirs enough to buffer magmatic inflow.

In this study, the structural controls of a high-temperature system (188 to 287 oC) associated with the detachment fault in Gediz Graben generating approximately half of this electricity generation in Turkey which is in the top five of the world in the generation of electricity from geothermal resources are examined. The high-temperature geothermal reservoirs associated with detachment fault in the study area have formed along the normal faults nearly in E-W orientation and in intensely fractured rocks in a structurally complex manner associated with transfer faults approximately in N-S orientation. Generally, it has been determined that the reservoirs are closely located to strike-slip faults intersecting, overlapping, and/or terminated with Quaternary transfer faults.  The same results as this study have also presented in the studies performed in western Anatolia and some regions of the world.  Since the detachment fault and the high-angle normal faults cutting the detachment fault form the paths, this mechanism ensures that the geothermal fluids are drained from the surface to the reservoir rock environment. High-angle normal faults cutting the detachment fault and the transfer faults cutting the detachment-high-angle normal faults constitute the carrier systems. This causes that the fluids heated in the reservoir rock environment at the depths are carried to the surface. Therefore, transfer faults control the position of high-temperature geothermal systems and should be used as the primary guide for geothermal exploration.
Keywords: high-temperature geothermal field, detachment fault, transfer fault, listric faulting, Western Anatolia

Geothermal heat pumps are an energy efficient option for many residences as an alternative to more conventional gas or oil fueled residential HVAC systems. This paper continues discussions about the noise and vibration issues from these residential geothermal systems that have been presented in prior papers by this author. In this paper, the noise contributions of two components of the ground water system will be discussed. First, the paper will discuss the influence of noise from the control system that regulates the ground water flow. A comparison of the noises from a simple pressure switch system versus a variable speed controller will be discussed. Second, the ground water system includes zone control valves to manage the water flow for the different systems. These valves can contribute to the noise generated by the system when it operates. Two types of valves will be discussed, which have dramatically different designs and different sound emissions. The paper concludes with recommendations for achieving a low noise ground water system to serve the geothermal heat pumps.

We report here occurrence of polymetallic sulphide mineralization near Gasku, about 6 km north of Tawa-ghat in Kali valley. The minerals in the ore assemblage include chalcopyrite, pyrite, sphalerite, minor galena and pyrrhotite. They are present in the sericite– muscovite–talc–chlorite (± biotite) schist, and in the quartz veins present in these schists as well as in the amphibolite of the Chiplakot Crystalline Belt, localized in the vicinity of the North Chiplakot Thrust. The initial results of ore chemical and the fluid inclusions studies are presented, and a hydrothermal origin is plausible for this mineralization.

Alp-Himalaya tektonik kuşağı üzerinde bulunan ülkemiz, zengin jeotermal kaynaklara sahip ülkelerden birisidir. Doğal, temiz, ucuz, emniyetli ve yenilenebilir bir enerji kaynağı olan jeotermal enerji, gelecekte de alternatif bir enerji kaynağı olacaktır. Hava kirliliği yüksek iller arasında yer .alan Afyon, aynı zamanda önemli bir jeotermal potansiyele sahiptir. Bu potansiyeli değerlendirmek üzere, 1994 tarihinde kurulan ve 1996 yılında işletmeye alman Afyon Jeotermal Enerji Isıtma Sistemi'nin kurulu kapasitesi 10.000 konut olup, halen 3.970 konut başarılı bir şekilde ısıtılmaktadır. Afyon'da her 100 m2 net alanın ısıtılması için gerekli olan ısı ihtiyacı 8.484 kCal/saat olup, jeotermal enerji ile ısıtılan 3.970 konut ve eşdeğeri 426.099 m2 konut alanı için harcanan enerji 30.727.700 kCal/saat'tir. Bu enerji, saatte yaklaşık 7 ton Tunçbilek kömürünün  yakılması ile elde edilen ısı enerjisine eşdeğer bir enerji olup, bir yıl içinde tasarruf edilen kömür miktarı (Tunçbilek kömürü) yaklaşık 30.000 ton'dur. Jeotermal enerji yerine Tunçbilek kömürü yakılarak bu konutlar ısıtılmış olması halinde, her yıl atmosfere yaklaşık 743 ton SOx ve 4.950 ton partikül madde karışmış olacaktı. Afyon örneğinden elde edilen bu sonuçlar, jeotermal ısınma ile binlerce ton SOx ve partikül madde emisyonunun önlendiğini ve jeotermal enerjinin sadece ucuz bir alternatif enerji kaynağı olmayıp, aynı zamanda çevre dostu bir enerji olduğunu da göstermektedir.

In Greece, several areas are presenting geothermal anomaly, which is controlled by the tectonic setting of each area, such as active graben and continental rift systems and in many cases these anomalies are related also to the recent volcanism. Two of these areas are the northwestern Euboea Island and the neighboring part of the mainland, i.e. eastern Sperchios area, Greece. These areas include several hot springs and active thermogenic travertine deposits, which are the surface manifestations of a geothermal system, recognized as having one of the highest geothermal gradient in Greece, just after the south Aegean active volcanic arc areas. Field surveys verified the presence of hot springs with fluid temperature over 82 oC. Geological, geochemical and isotopic data, alongside with drilling data suggest the presence of several medium and low enthalpy geothermal resources in these areas. Until now, the only use of these renewable energy resources is limited to thermal bath / spa therapies. Taking under consideration the geological, geomorphological, climate characteristics, the economic activities of the local societies, and the existing infrastructure, we suggest a series of targeted geothermal direct use applications that could be easily applied in these areas. Their application will have multiple positive socio-economic effects to national and regional level, resulting to the sustainable development of the areas, through the exploitation of a renewable energy resource i.e. the geothermal energy.

Geothermal resource is a clean energy resource in the earth crust related to convections of ground water transporting heats (thermal energy) from deep levels to shallower depths where the thermal energy can be tapped and utilised economically. Based on temperature, this resource can be classified into (i) high temperature or high enthalpy geothermal resources (water temperature ≥225•C), (ii) intermediate temperature or intermediate enthalpy geothermal resources (125•C ≤ water temperature<225•C) and (iii) low temperature or low enthalpy resources (40•C≤ water temperature <125•C). High temperature resources occur over the regions with heat flows equal or greater than 65 watts per m 2 , associated with volcanic zones near active margins of lithospheric plates or close to the earth hotspots. In high enthalpy geothermal resources, the thermal energy can be converted to electricity using direct flash turbine generator. Intermediate temperature resources also occur near active margins of lithospheric plates, or hot spots. In intermediate enthalpy geothermal resources, the thermal energy can be converted to electricity in the power plants with the help of a secondary fluid of low boiling point to drive turbine generator. Such power plant is known as binary cycle power plant. Alternatively, the heat from high enthalpy or intermediate enthalpy geothermal resources is used directly for drying timbers. Low temperature geothermal resources can occur anywhere. Low enthalpy geothermal resources provide thermal energy that can be used for space heating, drying crops, or running air conditioning systems (reverse heat pumps) for cooling. The geological conditions favourable for the existence of geothermal resources, and the extent of the geothermal reservoirs can be explored using appropriate geophysical methods. The geophysical measurements can be made on the ground surface, or from an aircraft flown over the explored area. This book describes and discussed the geophysical methods that have been used for the explorations of geothermal resources during the last 60 years. It provides important reference for academics as well as for earth scientists working with a geothermal power company.

The abundance of renewable resources is becoming one of
the most significant characteristics of Icelandic society as
nearly 80% of energy used could be categorized as clean.
Making use of geothermal water is of vital importance
here. Harnessing hot water from the earth is a far from a
straightforward task; furthermore, it is unique in that it
has become the dominant form of energy use in a whole
society. Here the principal focus will be on a partial aspect
of geothermal use, i.e. the culture of public outdoor bathing
that, surprisingly, has become one of the most significant
features of the Icelandic way of life, – implausible as it
might seem in view of Iceland's ‘topographical’ location,
an island in the middle of the North Atlantic.

Tattapani hot springs are located near the Kotli District of Azad Kashmir, Pakistan. This study evaluates these hot springs based on surface geological information, radon emission measurements, hydro-geochemical and isotopic signatures and potential source mechanisms. Field observations reveal that the hot springs are located at the crest of the Tattapani anticline along the faulted contact of Cambrian carbonates with Paleocene siliciclastics. In addition, remnants of igneous intrusions in the Cambrian carbonates are commonly observed. Spatial distribution of radon emissions (ranging between 2.1 and 29.5KBq m-3) indicates an anomalous zone located over the Cambrian-Paleocene faulted contact. Hydro-geochemical data show sodium-bicarbonate affinity of hot springs. The highest surface temperature of these springs is recorded at 60.8oC. Average reservoir temperatures based on silica and cation geo-thermometers are 101oC and 115oC, respectively. Giggenbach ternary diagram (Na-K-Mg) sugge...

Energi panas bumi adalah energi panas alami dari dalam bumi yang ditransfer ke permukaan bumi secara konduksi dan konveksi. Energi panas bumi juga merupakan sumber daya alam yang terbarukan dan ramah lingkungan. Indonesia diperkirakan memiliki sekitar 40% cadangan panas bumi dunia, setara dengan sekitar 28.000 MW listrik, salah satu sumber daya panas bumi terbesar di dunia. Rasio elektrifikasi Indonesia pada tahun 2009 sekitar 65%, dan pemanfaatan energi panas bumi untuk kelistrikan di Indonesia masih sangat rendah, sekitar 1.189 MW. Eksplorasi panas bumi di Indonesia bukanlah hal yang baru, bahkan hal ini dimulai sejak masa kolonialisme yang berlangsung di sekitar Kawah Kamojang pada tahun 1918, dan dilanjutkan dengan eksplorasi lima titik sumur pada tahun 1926 hingga 1929. Salah satu dari sumur tersebut yaitu sumur KMJ-3 bahkan masih beroperasi hingga saat ini (Saptadji, 2003). Pemerintah Indonesia telah berusaha memberikan iklim investasi yang lebih baik untuk pengembangan panas bumi di Indonesia dengan menerbitkan peraturan dan keputusan presiden untuk mendukung pengembangan di masa depan. Pada paper ini menggunakan hasil analisis deskriptif berbasis data sekunder, menggambarkan peluang energi panas bumi sebagai energi alternatif untuk mengurangi ketergantungan pembangkit listrik pada bahan bakar fosil dan kebijakan pemerintah terkait dapat dikembangkan untuk pengembangan energi panas bumi di Indonesia.

Although potassium-related classical geothermometers have been widely used over the years to estimate the temperature of geothermal reservoirs, there are limitations regarding their practical applications. In order to obtain more reliable reservoir temperature estimates, the limitations and the advantages of classical geothermometers must be realized and understood prior to their selection and application. In this study, the hydrogeochemical data for 239 water samples from geothermal wells drilled into crystalline basement reservoirs across the world were collated and analyzed to obtain the applicability conditions of K-related classical geothermometers from the scientific literature. Of these samples, 44 are of special interest being unaffected by mixing and because their reservoir temperature is known. The study shows that generally, the Na-K geothermometer gives valid estimates of reservoir temperatures above 200 °C. However, that is not the case in lower-temperature reservoirs since the equilibrium between albite, K-feldspar, and the aqueous solution is not always achieved, and the Na-K ratio of the primary fluids in the host reservoirs may change due to mixing taking place during the ascent of these thermal waters which have relatively low Na and K concentrations. At high temperatures, especially above 250 °C, reservoir temperature calculations for the use of the K-Mg geothermometer showed relatively large deviations from the measured temperatures. The K-Mg geothermometer seems to work well for mid-low temperature reservoirs (below around 150 °C), and the deviations from the reservoir temperatures probably result from the low activities of clinochlore in chlorites. Moreover, the performance of the K-Mg geothermometer is negatively affected by mixing of the thermal waters with other kinds of groundwater. The Na-K-Ca geothermometer may play a complementary role for evaluating reservoir temperatures above 200 °C but should be applied with caution when calcite precipitation triggered by degassing of the thermal waters takes place.

Along Java Island, there are more than 20 geothermal areas, including the Parang Wedang geothermal field. This field is classified as a non-volcanic geothermal system, because it is not associated with any active volcano. Permeable fault zones play an important role in fluid pathway occurrences. However, what is the source of the fluid is still debatable. Here we show results of geochemistry data analysis to determine the characteristics of Parang Wedang geothermal fluid. Cl-HCO 3-SO 4 ternary diagram of the Parang Wedang geothermal fluids reveals that the fluids contain high chloride. Additionally, Na-K-Mg ternary diagram of the fluid samples shows a character of partial equilibrium. It is possible that the geothermal fluids originate from magmatic activity related to the subduction process upward and mix with meteoric water. And then, these mixed water move upward further to the surface before the water reach full equilibrium. Our interpretation is consistent with seismology tomography studies that indicate magmatic fluid pathway from the subduction of Eurasian and Australian plates.

Aquae Patavinae. Montegrotto Terme e il termalismo in Italia. Aggiornamenti e nuove prospettive di valorizzazione, Atti del II Convegno Nazionale (Padova, 14-15 giugno 2011), a cura di Maddalena Bassani, Marianna Bressan, Francesca Ghedini, Antenor Quaderni 26.

The study of cult findings near thermo-mineral sites in Roman Italy is part of the widest research on thermal bathing, that started in the Archaeology Department of the University of Padua in 2010. This contribution begins by offering some preliminary remarks to explain the methodology used for this kind of search, in relation to various situations of more or less structured votive deposits, heavi­ly depicted sacred spaces, and also actual temples near springs and thermal baths. Secondly, some sites between Lazio, Campania and Sicilia are proposed, beginning from the pre-Roman shrine in the Montegrotto Terme thermal area (Padua), since they offer interesting elements for the definition of the different issues that arose. Among these, the location and hydrologic nature of the sites are discussed, together with the structural morphology and the types of votive artefacts, and including chronological data, in order to trace a preliminary timeline about the springs’ attendance. The conclusion suggests some interpretation hypotheses arising from the comparison of the archaeological records and a famous epistle by Plinius the Younger, where he describes the Clitumnus springs.

Scaling is frequently observed in geothermal fields and reduces the energy harvesting of power plants. Recently, Sb-rich deposits have developed in many fields around the world. Various polymeric macromolecules have been used as antiscalants to mitigate the formation of scale. Testing potential commercial antiscalants in field conditions is a tedious and costly process. The artificial synthesis of geothermal deposits in the lab is a more practical and economical way to test the performance of antiscalants. This study obtained a Sb-rich deposit by refluxing SbCl 3 and Na 2 S·3H 2 O in 18 h. The product was found to be a mixture of Sb 2 O 3 and Sb 2 S 3. We examined the performance of antiscalants such as poly(ethylene glycol), poly(vinyl pyrrolidone), Gelatin, and poly(vinyl alcohol) of various molecular weights at 5 to 100 ppm. The formation of Sb 2 S 3 is suppressed in the presence of the polymeric antiscalants. The dosage was found to be critical for the solubilization of Sb-rich deposits. Gelatin of 5 ppm showed the highest performance under the conditions employed in this study. While low dosages improve the concentration of [Sb 3+ ], high dosages are required to increase the solubility of [S 2-]. Moreover, the amount of deposit is reduced by 12.4% compared to the reference (in the absence of any polymeric molecules). Thus, comparatively, Gelatin shows the most promising performance among the molecules employed.

Of all possible forms of energy substitution of oil and gas, geothermal energy is the one most closely related to geology. Shallow geothermal energy is a source of clean, renewable and virtually inexhaustible energy that is directly related to geographical areas, where heat fluxes and temperature gradients can vary due to several factors. This document summarises the current situation of the policies on the use of shallow (low temperature) geothermal energy in Europe to generate hot water and air conditioning. The current status of legislation in some European countries and the promotion of shallow geothermal energy in the EU28 are also discussed.

Çürüksu (Denizli) Graben hosts various geothermal fields such as Kızıldere, Yenice, Gerali, Karahayıt, and Tekke-hamam. Neotectonic activities, which are caused by extensional tectonism, and deep circulation in sub-volcanic intrusions are heat sources of hydrothermal solutions. The temperature of hydrothermal solutions is between 53 and 260 degree Celsius. Phyllic, argillic, silicic, and carbonatization alterations and various hydrothermal minerals have been identified in various research studies of these areas. Surfaced hydrothermal alteration minerals are one set of potential indicators of geothermal resources. Developing the exploration tools to define the surface indicators of geothermal fields can assist in the recognition of geothermal resources. Thermal and hyperspectral imaging and analysis can be used for defining the surface indicators of geothermal fields. This study tests the hypothesis that hyperspectral image analysis based on EO-1 Hyperion images can be used for the delineation and definition of surfaced hydrothermal alteration in geothermal fields. Hyperspectral image analyses were applied to images covering the geothermal fields whose alteration characteristic are known. To reduce data dimensionality and identify spectral endmembers, Kruse's multi-step process was applied to atmospherically and geometrically-corrected hyperspec-tral images. Minimum Noise Fraction was used to reduce the spectral dimensions and isolate noise in the images. Extreme pixels were identified from high order MNF bands using the Pixel Purity Index. n-Dimensional Visualiza-tion was utilized for unique pixel identification. Spectral similarities between pixel spectral signatures and known endmember spectrum (USGS Spectral Library) were compared with Spectral Angle Mapper Classification. EO-1 Hyperion hyperspectral images and hyperspectral analysis are sensitive to hydrothermal alteration minerals, as their diagnostic spectral signatures span the visible and shortwave infrared seen in geothermal fields. Hyperspectral analysis results indicated that kaolinite, smectite, illite, montmorillonite, and sepiolite minerals were distributed in a wide area, which covered the hot spring outlet. Rectorite, lizardite, richterite, dumortierite, nontronite, erionite, and clinoptilolite were observed occasionally.

For promoting the diffusion of GSHP (Ground Source Heat Pumps) a tool for sizing these systems will be carried out in the H2020 research project named &quot; Cheap GSHPs &quot;. The paper presents the set up of a database with energy profile of a certain amount of buildings representative of the typology (single family houses, block of flats, office buildings) with different insulation levels and in different climatic conditions. Based on the weather analysis among European climatic files, twenty locations have been considered. For each location the overall energy and the mean hourly monthly energy profiles for heating and cooling (sensible and latent) have been calculated. Based on the results, the correlations with Degree Days (DD) for heating

For promoting the diffusion of GSHP (Ground Source Heat Pumps) a tool for sizing these systems will be carried out in the H2020 research project named “Cheap GSHPs”. The paper presents the set up of a database with energy profile of a certain amount of buildings representative of the typology (single family houses, block of flats, office buildings) with different insulation levels and in different climatic conditions. Based on the weather analysis among European climatic files, twenty locations have been considered. For each location the overall energy and the mean hourly monthly energy profiles for heating and cooling (sensible and latent) have been calculated. Based on the results, the correlations with Degree Days (DD) for heating and cooling have been found in order to generalize the results to have pre-calculated profiles for sizing GSHP.

We propose a standard hybridizable discontinuous Galerkin (HDG) method to solve a classic problem in fluids mechanics: Darcy's law. This model describes the behavior of a fluid trough a porous medium and it is relevant to the flow patterns on the macro scale. Here we present the theoretical results of existence and uniqueness of the weak and discontinuous solution of the second order elliptic equation, as well as the predicted convergence order of the HDG method. We highlight the use and implementation of Dubiner polynomial basis functions that allow us to develop a general and efficient high order numerical approximation. We also show some numerical examples that validate the theoretical results. Keywords: Hybridizable discontinuous Galerkin methods; flow in porous media; Dubiner's basis; high order convergence. Método HDG de orden superior con bases de Dubiner para problemas de flujo elípticos Resumen En este artículo proponemos el uso del método de Galerkin discontinuo híbrido (HDG) para resolver un problema clásico en mecánica de fluidos: la ecuación de Darcy. Este modelo describe el comportamiento de un fluido a través de un medio poroso y es relevante en el estudio de flujo a gran escala. Aquí presentamos algunos resultados teóricos de existencia y unicidad de la solución débil y discontinua de ecuaciones elípticas de segundo orden, así como el orden de convergecia predicho para el método HDG. Destacamos el uso e implementación de bases polinomiales de Dubiner que nos permiten desarrollar aproximaciones numéricas generales y de alto orden. Además mostramos ejemplos numéricos que validan los resultados teóricos. Palabras clave: Método de Galerkin discontinuo hibridizable; flujo en medio poroso; bases de Dubiner; convergencia de alto orden.

Geopressured-Geothermal Resource Potential in the Gulf Coast: Part II As a continuation of a brief update on the investigation of the potential development of geopressured geothermal energy in the Gulf Coast, this paper (Part 2) will address a previous DOE feasibility project, an ongoing commercial scale feasibility project, expert opinions on the cost effectiveness of this development, and the most recent cost analysis. Previous Pilot Project (1979) Because the Gulf Coast had been identified as having the largest reserves in geopressured geothermal in the U.S., The Department of Energy built a demonstration plant in Texas which produced electricity from geopressured resources. Preliminary testing took place during 1979, reservoir limits testing during 1980, and long-term testing was conducted during 1981-1983. According to the Geothermal Energy Association, the plant was dismantled after being deemed a success. Current Feasibility Project The recent $5,000,000 DOE grant to test the feasibility of this resource will hopefully help to answer some of the questions unanswered about the previous pilot project and about market dynamics that may have changed over the last 20+ years. This project is specifically targeted at demonstrating innovative site characterization and/or drilling exploration technologies. It will also explore energy production from low temperature resources, coproduced fluids from oil and gas wells, and geopressured resources. Lastly, it is expected to produce useful geothermal data development, collection and maintenance information. Unfortunately, it is not expected to produce any kind of cost analysis. Incomplete and Outdated Cost Analysis Unfortunately, no comprehensive studies to determine the commerciality of geopressured aquifers have been performed for almost twenty years. Conclusions stating that this technology was not economically feasible are limited to studies that were focused on large scale production in 1979 and/or specifically on methane production. Any negative conclusions about the pilot project in Texas (in 1979) would likely be reversed in the face of advances in technology and innovation. That particular pilot project did not investigate direct use applications, for example. It should also be noted that a comprehensive assessment of integrated applications has not been conducted. In addition to power generation, there are numerous industrial, agriculture and aquaculture applications that could use the energy contained in geopressured fluid and gases. Most Recent Cost Analysis A recent study's (J.S. Griggs, 2004) relevant conclusions stated that Commercial production of geopressured-geothermal aquifers is feasible under reasonable assumptions of natural gas and electricity pricing. The study also acknowledged equitable opportunities in the event that micro-scale grid or direct-use applications were used as well as if tax incentives were introduced in early stages. Griggs identified reasonable constraints to the commercial development and point to a clear need for the ongoing feasibility project (and a comprehensive cost analysis), which included: reservoir characterization and resource estimation; facility optimization and system analysis; high efficiency binary-cycle power plants; detailed economic analysis; and legal and political barriers.