Geothermal Reservoir Research Papers - Academia.edu (original) (raw)

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

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- Geothermal, Geothermal Energy, Tugas kuliah, Geothermal Reservoir
- by dorottya bartucz
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- Geothermal Reservoir

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.

- by Marion Tichomirowa
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- Water, Permian, Geothermal Reservoir, Sr isotopes

In this study, one of renewable energy sources, geothermal fluid(brine water) viscosity calculations for geothermal power plant are specified. The calculations of flow stability are compared with ‘’Pipe Flow Expert’’ program. Due to the fact that Geothermal fluid’s (brine water) chemical properties are similar to seawater, El Doussky and J.Sündermann 's studies and researches are based on . Also fluid movement function (Laminar or Turbulent) is investigated in drawn and welded steel pipes and based on these studies, calculations are made with cathodic protection and galvanic anode applications related to mechanical and chemical corrosion and a study is presented including many issues, the theoretical and practical knowledge.

- by Ahmet Oven
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- Renewable Energy, Energy, Geothermal, Energy and Environment

Indonesia merupakan salah satu negara yang berpotensi memiliki banak sumberdaya panas bumi. Potensi panas bumi yang dimiliki Indonesia mencapai 40% dari total potensi yang dimiliki dunia. Bahkan di Kabupaten Semarang, Jawa Tengah mempunyai potensi panas bumi yang cukup memadai untuk dikembangkan, seperti lapangan panas bumi Gedong Songo. Temperatur yang didapatkan dengan menggunakan metode gas geothermometer cukup tinggi sehingga daerah Geothermal Gedong Songo mempunyai potensi digunakan untuk sumber tenaga listrik dan kegiatan perekonomian lainnya. Oleh karena itu perlu diadakan pembelajaran lebih lanjut terkait Geothermal Gedong Songo.

- by zufita khairani
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- Geothermal, Geothermal Energy, Geothermal Reservoir, Central Java

A brief discussion and review of the geothermal reservoir systems, geothermal energy and modeling and simulation of the geothermal reservoirs has been presented here. Different types of geothermal reservoirs and their governing equations have been discussed first. The conceptual and numerical modeling along with the representation of flow though fractured media, some issues related to non isothermal flow through fractured media, the efficiency of the geothermal reservoir, structure of the numerical models, boundary conditions and calibration procedures have been illustrated. A brief picture of the Indian scenario and some barriers related with geothermal power are discussed and presented thereafter. Finally some gaps of the existing knowledge and recent focuses of research are discussed.

- by Sayantan Ganguly
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- Geothermal Energy, Review, Geothermal Reservoir

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.

- by Bintang Rajasanegara
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- Geology, Geothermal Energy, Geothermal Reservoir, Geothermal Systems
- by Willant Zoltán
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- Geothermal Reservoir, Danube region

The use of groundwater systems for heat storage increasingly gains interest among water managers, policy makers and researchers as a way to increase the efficiency of energy production and to allow the re-use of waste heat. Typically, mono-well storage systems are thought to require the use of separate aquifers. This study assessed the suitability of using heat and cold storage in a single deep geothermal aquifer for district heating and cooling. An integrated modelling approach was used for evaluating the controls on the energy efficiency of high temperature aquifer thermal energy storage (HT-ATES). The temperature difference (T) of 40 • C between the injection temperatures for the cold and warm storages 20 • C and 60 • C was significant, which required accounting for transient variation of density and viscosity due to temperature and pressure within the modelling code SEAWAT. The developed model was applied for a geothermal reservoir from the Moesian platform, in the Bucharest area, Romania. The sensitivity of the system efficiency was analyzed with respect to the main physical (density, viscosity, longitudinal dispersivity) and operational design parameters (distance between warm and cold storage volumes, flow rates). Uncertainties in geological heterogeneity and the associated range in longitudinal dispersivity values (5–50 m) resulted in significant efficiency differences (80–55%). While reducing the lateral distance between multiple mono-well systems increased their overall efficiency due to positive thermal interference , a minimum vertical distance of (160 m) was required between the injection/extraction filters to prevent interaction between the cold and warm storage volumes. Overall, this study highlights the potential of using a cost-effective mono-well system for HT-ATES in single deep geothermal groundwater systems.

- by Gualbert Oude Essink and +1
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- Hydrogeology, Heat and Mass Transfer, Geothermal Reservoir, Variable density flows

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

- by Dr.Adil Ozdemir
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- Faulting (Structural Geology), Geothermal, Geothermal Energy, Detachment

The Kamojang geothermal field is located in the active volcanoes belts so that geological activities is high enough which is indicated by local faults or fractures. They could cause earthquake. For reservoir management, microearthquake monitoring (MEQ) was needed. During the period of investigation from March 2004 to February 2005, 275 times of micro earthquake and 115 times of macro earthquake have been recorded. Most of the earthquake occur in Kamojang geothermal field which are caused by a structure movement and the changing of hot fluid phase to steam from fluid injection. Meanwhile the macro earthquake which are located outside of Kamojang geothermal field are caused by tectonic aspect. The distribution pattern of epicenter show that the current direction of fluid injection toward active production wells area, however there are some fluid injection moved to Northwest – Southwest around Kmj-21 injection well that follow the existing fractures in that area. The interpretation of hypocenter is from 0,02 km to 17,01 km in depth. Most of hypocenter located below the reservoir zone with elevation from 0 to -3 km. West – East cross-section of hypocenter show that the trend of hypocenter is Southwest – Northwest direction, this is similar with the fault zone structure.

- by anik hilyah
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- Geothermal, Microseismic Monitoring, Geothermal Reservoir, Geothermal Exploration

An analytical solution to describe the transient temperature distribution in a geothermal reservoir in response to injection of cold water is presented. The reservoir is composed of a confined aquifer, sandwiched between rocks of different thermo-geological properties. The heat transport processes considered are advection, longitudinal conduction in the geothermal aquifer, and the conductive heat transfer to the underlying and overlying rocks of different geological properties. The one-dimensional heat transfer equation has been solved using the Laplace transform with the assumption of constant density and thermal properties of both rock and fluid. Two simple solutions are derived afterwards, first neglecting the longitudinal conductive heat transport and then heat transport to confining rocks. Results show that heat loss to the confining rock layers plays a vital role in slowing down the cooling of the reservoir. The influence of some parameters, e.g. the volumetric injection rate, the longitudinal thermal conductivity and the porosity of the porous media, on the transient heat transport phenomenon is judged by observing the variation of the transient temperature distribution with different values of the parameters. The effects of injection rate and thermal conductivity have been found to be profound on the results.

- by Sayantan Ganguly
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- Heat Transfer, Laplace Transform, Geothermal Reservoir, Analytical Solution
- by Sayantan Ganguly
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- Geothermal Energy, Geothermal Reservoir, Geothermal Power Plant

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.

In this study a new approach to geothermal potential assessment was set up and applied in four regions in southern Italy. Our procedure, VIGORThermoGIS, relies on the volume method of assessment and uses a 3D model of the subsurface to integrate thermal, geological and petro-physical data. The method thus produces 2D geothermal potential maps for three different uses: district heating, district heating and cooling, and electrical power production. Our study focused on carbonate reservoirs, which usually present an excellent natural permeability and important geothermal gradients at depth. Our computations were possible thanks to the large quantity of data available from hydrocarbon exploration that largely investigate deep-seated reservoirs. Based on geothermal potential available for power production we estimate the contribution of the geothermal energy in the CO 2 emissions reduction in the study regions. Moreover policy makers as well as investors can use our maps to establish new policies and to locate the most promising places for geothermal development, in line with the international low carbon strategy.

- by Eugenio Trumpy and +4
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- Geothermal Energy, Geothermal Reservoir, Southern Italy, Emissions Reduction

Περίληψη
Στο πλαίσιο της διερεύνησης της παρουσίας πιθανών γεωθερμικών πεδίων στην Κρήτη μετρήθηκαν οι θερμοκρασίες και προσδιορίσθηκαν τα φυσικοχημικά χαρακτηριστικά νερών από επτά γεωτρήσεις στην περιοχή της Μεσσαράς σε τρεις περιόδους: δύο θερμές (6-7/2015 και 2016) και μια ψυχρή (2/2016). Η παρούσα εργασία πραγματεύεται πέραν της παρουσίασης των πρόδρομων αυτών στοιχείων σχετικών με πιθανούς γεωθερμικούς ταμιευτήρες χαμηλής ενθαλπίας στη Μεσσαρά της Κρήτης και στη στοιχειοθέτηση των μηχανισμών γένεσης των, εντός των αλπικών σχηματισμών και πολύ πιθανά εντός των ανθρακικών σχηματισμών της ζώνης της Τρίπολης. Οι προτεινόμενοι πιθανοί μηχανισμοί δημιουργίας τους συνδέονται είτε με την έντονη νεοτεκτονική δραστηριότητα της περιοχής που οδήγησε στη δημιουργία ρηγμάτων μεγάλου βάθους, με τα οποία συνδέονται κατεισδύοντα μετεωρικά νερά, είτε με τοπικά αυξημένη γεωθερμική βαθμίδα που πιθανά να συνδέεται με τη σειρά της είτε με ενταφιασμένα πλαγιογρανιτικά σώματα μικρών διαστάσεων, είτε με διαδικασίες ενυδάτωσης ανυδρίτη σε γύψο στον υποκείμενο των ανθρακικών σχηματισμών της ζώνης της Τρίπολης.
Abstract
The past few years, great efforts have been made in Greece for the detection, recording and partly for the development of geothermal potential. Apart from some indications in eastern and western Crete, irrigation wells drilled in Messara valley-central Crete give increased temperature water. More specifically, the water temperature of irrigation wells-located at Villages of Peri, Platanos and Melidochori-that was monitored during the wet and dry periods (2015-2016) indicates the existence of potential geothermal fields in the area. Geological evidence are utilized to support the existence of low enthalpy reservoirs hosted in the Alpine formations and more possible within the carbonate formations of Tripolis zone. A possible explanation for the increased water temperature is that the mean heat flux-calculated at 60 mW/m 2 in the region of Messara-increases along major fault zones within which circulates the water. These major fault zones are active since Middle Miocene and were repeatedly reactivated. The increase in thermal flux in these major fault zones could be associated with an increased geothermal gradient. In turn, the increased geothermal gradient could be related to either a possible existence of plagiogranite bodies hosted in the tectonic sequence of the upper units affected and adjacent to these fault zones, or the existence of anhydrate, hosted in the clastic substratum of Tripolis zone that are altered to gypsum via an exothermic reaction with the presence of water.

- by Emmanouil Manoutsoglou
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- Crete, Geothermal Reservoir, Geothermal Exploration, Messara

The Taupo Volcanic Zone (TVZ) is a NNE-trending rifting arc, characterized by extensive volcanism. Associated with this volcanism high-temperature (>250°C) geothermal fields occur with convective circulation to depths of 7–8 km. The purpose of this study is to create a representative model of the deep hydrothermal convection of the TVZ. Study investigates the variables that are affecting the major features controlling the geothermal fields distributed throughout the area. Model encompasses 21 geothermal fields, namely Kawerau, Rotoma, Tikitere/Rotoiti, Taheke, Rotorua, Horohoro, Waimangu, Waiotapu-Waikite, Reporoa, Te Kopia, Ohaaki, Orakeikorako, Ngatamariki, Atiamuri, Rotokawa, Ongarato, Mangakino, Mokai, Wairakei, Tauhara, and Lake Taupo.
The model was divided into two main regions, the interior region and exterior region. Interior region is bounded by the Kaingaroa Fault to the East, with the Taupo Fault Belt (TFB) presented in the centre of the TVZ. The heat flow at the base of the exterior region is set to the normal terrestrial flow of 0.09 W/m2, while the heat distribution at the base of the interior region is varied to achieve the measured heat output at the surface. Dominating geological structures such as caldera boundaries, distribution of greywacke basement and faults that provide the permeability needed to facilitate the movement of fluids in the system were inferred from recent geological and geophysical studies. The distribution of heat at the base of the model (approximately 6.7 km) and the permeabilities of geological structures were the parameters to be estimated. The model was calibrated to predict the location of discrete plumes, magnitude of heat discharge from each field and reservoir temperature.

- by Eylem Kaya
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- Natural Convection, Geothermal Reservoir, Taupo Volcanic Zone
- by Sonja Philipp and +1
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- Geology, Hydrogeology, Volcanology, Structural Geology

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.

- by AMANDA HAIQAL 2020
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- Renewable Energy, Energy, Geothermal, Natural Science
- by Sayantan Ganguly
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- Geothermal reservoir simulation, Geothermal Reservoir

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.

- by Gideon Sagoe
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- Geothermal, Water rock interactions, Geothermal Reservoir, Geothermics

Estimating values of permeability (k), efficient porosity (P) and hydraulic conductivity (K) by analysing field outcrops as analogue of geothermal reservoirs, is a timely theme useful for predictions during geothermal exploration programs. In this paper we present a methodology providing k, P and K values, based on geometric analysis of quartz-tourmaline faults-vein arrays hosted in micaschist exposed in southeastern Elba Island (Tuscan Archipelago, Italy), considered as the analogue of rock hosting the so-called "deep reservoir" in the Larderello geothermal field. The methodology is based on the integration among structural geology, fluid inclusions results and numerical analyses. Through a detailed structural mapping, scan lines and scan boxes analyses, we have reconstructed three superposed faulting events, developed in an extensional setting and framed in the Neogene evolution of inner Northern Apennines. Geometrical data of the fault-veins array were processed by reviewing the basic parallel-plate model equation for k evaluation. Fluid inclusion analyses provided those salinity and pressure-temperature values necessary for defining density and viscosity of the parent geothermal fluids. Then, permeability, density and viscosity were joined to get hydraulic conductivity (K). Permeability is estimated between 5 × 10 −13 and 5 × 10 −17 m 2 with variations among the different faults generation, while the hydraulic conductivity is encompassed between 1.31 × 10 −8 and 2.4 × 10 −13 m/s. The obtained permeability and hydraulic conductivity values are comparable with those from several geothermal areas, and in particular from the Larderello geothermal field. The main conclusion is that the proposed integrated approach provides a reliable methodology to obtain crucial values, normally obtained after drilling, for developing numerical flow models of geothermal fluid path in active geothermal systems by field and laboratory analyses of analogue, exhumed, geothermal systems.

- by Martina Zucchi and +1
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- Structural Geology, Geothermal, fluid Inclusions, Geothermal Reservoir

Hydrothermal activity at Campi Flegrei caldera is simulated by using the multiphase code MUFITS. We first provide a brief description of the simulator covering the mathematical formulation and its applicability at elevated supercritical temperatures. Then we apply, for the first time, the code to hydrothermal systems investigating the Campi Flegrei caldera case. We consider both shallow subcritical regions and deep supercritical regions of the hydrothermal system. We impose sophisticated boundary conditions at the surface to provide a better description of the reservoir interactions with the atmosphere and the sea. Finally we carry out a parametric study and compare the simulation results with gas temperature and composition, gas and heat fluxes, and temperature measurements in the wells of that area. Results of the parametric study show that flow rate, composition, and temperature of the hot gas mixture injected at depth, and the initial geothermal gradient strongly control parameters monitored at Solfatara. The results suggest that the best guesses conditions for the gas mixture injected at 5 km depth correspond to a temperature of ~ 700 °C, a fluid mass flow rate of about 50–100 kg/s, and an initial geothermal gradient of ~ 120 °C/km.

- by Giovanni Chiodini and +2
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- Numerical Simulations, Caldera Volcanoes, Geothermal Reservoir

This paper reports a three-dimensional (3D) numerical study to determine the effect of heat loss on the transient heat transport and temperature distribution in a geothermal reservoir. The operation of a geothermal power plant, which is essentially an injection-production process, involves reinjection of heat-depleted water after extraction of heat for power production which results in gradual cooling of the reservoir. This study aims at determining the influence of the heat loss from the geothermal reservoir to the surrounding rock media on the temperature distribution due to injection-production operations. Results show that the advancement of the cold-water thermal-front becomes slower due to heat loss which helps in delaying thermal-breakthrough at the production well. The permeability and the thermal conductivity of the confining rocks are found to be crucial parameters influencing the heat loss phenomenon and thus the thermal-front movement in the reservoir. In light of the importance of heat loss, a new strategy of reinjection is discussed here. Injection of cold water in a zone capped by rocks with significant permeability at a finite distance away from production zone is proven here to be a good strategy to avoid premature thermal-breakthrough while maintaining pressure balance.

Telah dilakukan penelitian tentang identifikasi reservoar panasbumi dengan metode geomagnetik daerah Blawan Kecamatan Sempol Kabupaten Bondowoso. Pengambilan data dilakukan dengan menggunakan alat Proton Precision Magnetometer (PPM-856), Global Positioning System (GPS) dan termometer. Luas area penelitian 1100 meter dan 650 meter dengan menggunakan spasi 50 meter. Pengolahan data menggunakan koreksi IGRF, diurnal, pengangkatan ke atas dan reduksi ke kutub yang berguna untuk memudahkan interpretasi. Nilai kontur anomali lokal sekitar -800 nT sampai 960 nT. Pemodelan 2 dimensi menggunakan metode talwani menghasilkan pola distribusi manifestasi panasbumi berasal dari Pegunungan Kendeng yang mengalir ke Blawan melalui celah atau patahan. Reservoar panasbumi belawan terjadi akibat adanya intrusi batuan gunungapi sehingga pada daerah tersebut memiliki nilai suseptibilitas yang rendah dan suhunya sangat panas. Potensi lokasi reservoar berada di penampang A-B pada kedalaman 889 meter dan D-E pada kedalaman 905 meter. Pemodelan 3 dimensi menghasilkan volume sebesar 133.16 juta m3, suhu reservoar 70.2oC dan rapat daya spekulatif 10 MW/km2 serta konversi energi 10%.

- by jurnal neutrino
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- Geomagnetism, Geothermal, Geothermal Reservoir, Bondowoso

Geothermal energy is seen as a most economical 24 x 7 energy in present days. The United Nations estimates global reserves at about 200 GW. ENEL Green Power has reported 1'263 MW of installed geothermal power capacity in 2015 and expects 2'144 MW by 2020. In 2015 the USA led the world in geothermal electricity with 3450 MW production followed by the Philippines, Indonesia, Mexico, Italy, New Zealand. Iceland has the highest percentage share of geothermal energy (5245 GWh) of their national electricity production and is now planning to export the surplus geothermal energy to Europe through submarine cables. Africa has great potential and initial experiments in the Kenya Rift valley and in Ethiopia have yielded good results. Today geothermal energy is cheaper than Hydropower in Kenya and they have a much cheaper source of fuel to replace fossil fuels on a sustainable basis. After the Fukushima Nuclear disaster the Japanese government was forced to shut down over 40 nuclear plants and shifts its focus to more geothermal energy to meet its energy requirements. Geothermal holds the key to solve the energy problem of the far over 2 Billion population of India and China on one hand and provides sustainable cheap and safe energy solutions to the MENA region. Agneyodgara (Lava Energy)-GEOCOGEN geothermal energy concepts aimed to produce plenty of GWh clean energy by tapping lava energy in geologically favorable environments at shallow depths use waste water from municipal waste and geothermal heat from earth to produce clean water and energy. The United Nations calls for "Sustainable Energy for All " coupled with the International Energy Organization's commitments of achieving universal energy access by using 100% renewable energy. Geothermal Energy holds one of the golden keys to fulfilling these objectives besides ending nuclear power plants which are bombs for our future generation on one hand and on the other hand the dependence on fossil fuel must be reduced. According to the International Sustainable Energy Organization ISEO geothermal solutions will not only provide sustainable, but also abundant economical and SAFE energy for all by 2050. Biography Dr Ritesh Arya Guinness World record holder is doctor in geology with interest in Water, Energy and Climate. His Mission is "Right to Free Safe Sustainable " Water & Energy " for All by 2050. He started his carrier as hydrogeologist to provide sustainable drinking water solutions based on groundwater development on NO WATER-.NO MONEY basis for civil uses and army. He worked with WaterAid to provide water solutions for Tibetans who migrated from Tibet in 1959 and settled in the Ladakh High altitude cold mountain deserts of the Himalaya, India. Today this group has rightly titled Dr Ritesh Arya "The Incredible Waterman". The Agneyodgara (Lava Energy)-GEOCOGEN concept developed by him to produce Giga Watts of green, clean, safe, FREE sustainable energy for all and was rated as " He presented Arya's C cycle-based on paleo climatic signatures discovered by him to show Climate change is a natural cyclic process, but pollution is manmade and needs to be tackled by improving technology by the Global Conference on Global Warming in 2015.

- by RITESH ARYA
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- Geothermal, Geothermal Energy, Geothermal Reservoir, Geothermal Heat Pumps

Περίληψη
Απώτερος στόχος της εργασίας αποτελεί η επιλογή του κατάλληλου γεωθερμόμετρου για την εκτίμηση της θερμοκρασίας πιθανών γεωθερμικών ταμιευτήρων, στη Μεσσαρά. Διαθέτοντας στοιχεία, όπως επιτόπιες μετρήσεις της θερμοκρασίας και του pH αλλα και του χημισμού, δοκιμάστηκε η εφαρμογή διαφορετικών γεωθερμομέτρων τα οποία θεωρούνται κατάλληλα για γεωθερμικά πεδία χαμηλής ενθαλπίας. Διαπιστώθηκε ότι το γεωθερμόμετρο που παρείχε ρεαλιστικές εκτιμήσεις είναι του Na-K-Ca με διόρθωση Mg. Με βάση τη χρήση αυτού του γεωθερμόμετρου η εκτιμώμενη θερμοκρασία στον πιθανό ταμιευτήρα στην περιοχή Μελιδοχώρι κυμαίνεται από 46 ο C (γεώτρηση Mel1)-51 ο C (γεώτρηση Mel2), στην περιοχή Πλάτανος εκτιμάται στους 45 ο C (γεώτρηση Plat2) ενώ για την περιοχή Περί η εκτίμηση της θερμοκρασίας για το πιθανό γεωθερμικό ταμιευτήρα κυμαίνεται μεταξύ 70 ο C-77 ο C για τα δείγματα από τις γεωτρήσεις Peri1 και Peri 3 αντίστοιχα.
Abstract
The main goal of this work is to choose the most suitable geothermometer, to predict the temperature of two potential low enthalpy reservoirs at Messara, Crete, Greece. In situ measurements, including water temperature and pH, laboratory analysis data from seven (7) irrigation wells, as well as geological evidence imply that a limited number of geothermometers are suitable for low enthalpy waters. These include the Fournier's Mg-corrected Na-K-Ca geothermometer which is empirical but suitable for a wide range of water temperatures and dissolved constituents, the Ca-Mg geothermometer which is also empirical but designed for low enthalpy water's circulating in Triassic evaporates and the Fournier's chalcedony geothermometer. The chalcedony geothermometer provided negative to underestimated values of the reservoir's temperature thus was rejected. The Ca-Mg resulted in temperature values similar to the measured at the surface. The most realistic results were provided by the Mg-corrected Na-K-Ca geothermometer. According to the results, the estimated reservoir temperature at Melidohori region varies from 46 ο C (sample Mel1) to 51 ο C (sample Mel2), while the estimated reservoir temperature at Platanos-Peri region is estimated from 45 ο C (sample Plat2) to 70 ο C-77 ο C for the samples from the wells Peri1 and 3.

- by Emmanouil Manoutsoglou and +1
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- Crete, Geothermal Reservoir, Messara, Geohemistry

An exact integral solution for transient temperature distribution, due to injection-production, in a heterogeneous porous confined geothermal reservoir, is presented in this paper. The heat transport processes taken into account are advection, longitudinal conduction and conduction to the confining rock layers due to the vertical temperature gradient. A quasi 2D heat transport equation in a semi-infinite porous media is solved using the Laplace transform. The internal heterogeneity of the geothermal reservoir is expressed by spatial variation of the flow velocity and the effective thermal conductivity of the medium. The model results predict the transient temperature distribution and thermal-front movement in a geothermal reservoir and the confining rocks. Another transient solution is also derived, assuming that longitudinal conduction in the geothermal aquifer is negligible. Steady-state solutions are presented, which determine the maximum penetration of the cold water thermal front into the geothermal aquifer.

- by Sayantan Ganguly
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- Geothermal, Geothermal Energy, Closed-Form Solutions, Analytical Modeling

In this work a review on the geomaterial aspects of geothermal energy will be presented based on scholarly articles and published materials. As introduction an overview of basic geothermal resource concepts such as the occurrence of geothermal energy, mechanisms of heat flow in the ground and its reservoir types will be explained. Following this, properties of geothermal reservoir formations like permeability and thermal properties of rocks will be presented in detail. Geothermal resource and reservoir characteristics exploration methods including geophysical, geochemical and thermal gradient wells are also broadly discussed in this review. Moreover, a brief presentation on the geothermal resource and related research activities in Ethiopia will be addressed. The objective of this review is to discuss the role of geomaterials on the utilization of geothermal energy. 1. Geothermal Energy Geothermal energy is the energy contained in the earth's interior. The source of heat to the planet earth is from both external and internal sources of energy. The major sources of external energy are from solar irradiation and gravitational force. The solar energy source is being the largest by providing about 1.5 x 10 22 J of energy to the earth's surface every day. On the other hand, the interior part of the earth receives energy from four major sources. These include the radiogenic heat, the original heat, potential and frictional energy. The radiogenic energy is the heat released from the decay of radioactive isotope elements that form the earth itself whereas the original heat is the heat content of the infant earth immediately after its formation. Potential energy is the energy released in the form of heat during the formation of new crust and finally the frictional heat is the heat that generates from the elastic energy released during the event of earthquakes. The largest internal energy source of the earth is from the decay of radioactive isotopes in the earth's interior and this is amounted to about 8.6 x 10 20 J of heat energy every year or it is about 62% of all the internal heat sources (Clauser, 2006). 2. Variation of Temperature in the Earth's Crust The temperature of earth's crust varies laterally as well as vertically depending on a number of factors. This irregular distribution of heat is due to factors such as the content of radioactive isotopes in the rock and the tectonic and hydrological nature of an area. The average values of temperature variability ranges from 10 Kelvin km-1 to 60 K km-1 in continental crust that has a thickness of 25 to 45 km. In oceanic crust of 5 to 8 km thickness the variation may be elevated much more than this due to the elevated hydrothermal activity in this environment (Clauser, 2006). 3. Types of Geothermal Reservoirs Various types of geothermal reservoirs exist in the earth's crust and underneath. These reservoirs can be classified by the level of its temperature and amount of fluid it contains. Geothermal energy of magmatic origin has the highest temperature and is relatively poor in water content. The range of temperature in magmatic environment varies from 650 to 1,300 o C depending on the chemical composition of magma (Sass and Duffield, 2003).

- by Worku Janka Negawo
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- Geothermal Reservoir, Geothermal Exploration

The case study area is part of a geothermal field located in the south western part of Regione Umbria where geothermal systems of medium-high enthalpy have been already explored and where one of the few authorized projects for future exploitation of geothermal resources in our territory is planned to start soon.
The synthetic maps in this report, though subject to some refinement due to the assumptions made and the not homogeneous distribution of the deep wells in the area, represent an effort to integrate all the available geological, geophysical and hydrogeological information available providing a model of the reservoir behaviour and a contribution to the geological and geothermal knowledge of the area.
In conclusion this study, integrated with further investigations like drilling new exploration wells, should help taking the next steps towards implementing sustainable energy solutions based on geothermal
resources.

- by Andrea Motti
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- Geothermal Reservoir, Geothermal Exploration, Geoenergy

Students design their own experiments and analyses of a proposed low enthalpy geothermal scheme.

- by Pam Dugdale
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- Renewable Energy, Geothermal, Geothermal Reservoir, Geothermal Exploration

EPT-L/2 is one of production well in geothermal prospective area to support steam supply into the existing power plant. During its production period, the well had a quite rapid decline among other wells due to scaling formation in this well. Hole cleaning and acidizing conducted to break the scale and the well was automatically shut-in during and after both treatment when the well had heated up, the discharge test was trying to asses well EPT-L/2 producibility. But, this well has decreased WHP during the discharge test rapidly, causing the well to not flow. Based on the latest Pressure & Temperature measurement data, it is known that there is a very significant increasing in temperature at depth of 230 mMD. Preliminary analysis of the possibility of a water pocket at that depth is heated by steam-heated water in a shallow aquifer. There is an indication of casing leak namely: There are 2 inflow points on the 13-3/8" casing which are at a depth of 223 mMD and 932 mMD and There is a temperature anomaly that is probably associated with cold water inflow into the casing 13-3 / 8 "at a depth of 223 mMD and 932 mMD. Another survey is needed to ensure that there is a leak/damage to the casing at the depth of the suspected damage to the casing. Well integrity surveillances have been conducted to unlock the root cause such as PTS Survey, Magnetic Thickness Detection survey. Acoustic Leak Flow Analyzer, Caliper Logging, and Downhole Sampling. Based on all the well integrity surveillance, those survey can confirm that there are some casing damage at depth 223 mMD, 390 mMD, 650 mMD, 932 mMD, which is characterized by the inflow of cold water appearance in production casing based on metal loses, soundwave sensor, and caliper data. The acid content of fluid either from steam-heated water or acid dumping during acidizing is negligible based on downhole sample analysis. Eventually, EPT-L/2 suggested being worked over for maintaining the production of the well.

- by Erwandi Yanto
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- Geothermal Reservoir, Geothermal Production Well
- by Agust Gudmundsson
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- Hydrogeology, Volcanology, Structural Geology, Geothermal

Temperature, pressure and enthalpy data is very important and valuable, both during geothermal drilling and in well operation. The study will research the possibility of direct downhole measurement of temperature and free calibration, which will result in a real time pressure and enthalpy reporting model. The research will report on the development of a downhole geothermal brine pressure and enthalpy model, applied to the state-space T-p-X delineations and density (ρ) correlations in flowing gas, liquid and two-phase systems, using the H2O–NaCl geothermal brine thermodynamic formulation. The model was implemented in C programming, running in the NI Lab Windows/CVI user interface. The model is highly dependent on the fibre optic temperature sensor system for a direct temperature measurement. The experiment works to extend the range of an existing calibration-free fibre optic temperature sensing technique based on photon counting measurements by Raman backscatter (previously developed in collaboration with the US National Institute of Standards and Technology). The research aim is to extend the range of the system to a kilometre length, by increasing the optical power per pulse and reducing the repetition rate of the excitation laser. For this experiment, the test will employ superconducting single photon detectors with improved efficiency (5%) housed in a practical, closed-cycle cooling system. The experiment managed to demonstrate the temperature measurement and estimate the enthalpy using 2 meter of fibre under test, which represent 2 meter of depth. Meanwhile, the experiment of 100 meter of fibre under test are still under investigation after successfully measured low temperature.

- by Anggoro Wisaksono
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- Two Phase Flow, Geothermal Energy, Temperature Sensors, Enthalpy
- by Marina Iorio and +4
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- Human Geography, Geology, Structural Geology, Renewable Energy

[1] The Campi Flegrei (CF) Caldera experiences dramatic ground deformations unsurpassed anywhere in the world. The source responsible for this phenomenon is still debated. With the aim of exploring the structure of the caldera as well as the role of hydrothermal fluids on velocity changes, a multidisciplinary approach dealing with three-dimensional delay time tomography and rock physics characterization has been followed. Selected seismic data were modeled by using a tomographic method based on an accurate finite difference travel time computation which simultaneously inverts P wave and S wave first-arrival times for both velocity model parameters and hypocenter locations. The retrieved P wave and S wave velocity images as well as the deduced V p /V s images were interpreted by using experimental measurements of rock physical properties on CF samples to take into account steam/water phase transition mechanisms affecting P wave and S wave velocities. Also, modeling of petrophysical properties for site-relevant rocks constrains the role of overpressured fluids on velocity. A flat and low V p /V s anomaly lies at 4 km depth under the city of Pozzuoli. Earthquakes are located at the top of this anomaly. This anomaly implies the presence of fractured overpressured gas-bearing formations and excludes the presence of melted rocks. At shallow depth, a high V p /V s anomaly located at 1 km suggests the presence of rocks containing fluids in the liquid phase. Finally, maps of the V p *V s product show a high V p *V s horseshoe-shaped anomaly located at 2 km depth. It is consistent with gravity data and well data and might constitute the on-land remainder of the caldera rim, detected below sea level by tomography using active source seismic data. Citation: Vanorio, T., J. Virieux, P. Capuano, and G. Russo (2005), Three-dimensional seismic tomography from P wave and S wave microearthquake travel times and rock physics characterization of the Campi Flegrei Caldera,

- by Tiziana Vanorio
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- Volcanology, Rock Physics, Earthquake, Carbonates
- by Assunta Donato
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- Geology, Geophysics, Geomatics, Geothermal Energy

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.

- by Jordan Lane Gilmore
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- Geology, Water, Geothermal, Natural Resource Management

- by Dr.Ir. Arief Rachmansyah
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- Geomagnetism, Geothermal, Neutrino, Geothermal Reservoir
- by SUKIR MARYANTO
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- Geomagnetism, Geothermal, Neutrino, Geothermal Reservoir
- by Guido Russo
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- Modeling, Sea Level, Multidisciplinary, Rock Physics

Before being disrupted by a magmatic event in 1999, the vent temperatures and salinities along the
axis of the Main Endeavour Field on the Juan de Fuca Ridge exhibited a quasi-steady spatial gradient in
which the southern vent fluids were hotter and less saline than the northern vent fluids. We present 2-D
numerical models of two phase flow in a NaCl-H2O system to understand these gradients. We consider
homogenous permeability models with a range of bottom boundary temperature distributions and
heterogeneous permeability models by imposing layer 2A extrusives with a constant bottom boundary
temperature distribution. The aim is to understand the impact of both bottom boundary temperature and
layer 2A permeability on hydrothermal fluids and to determine what combination of these controlling
factors could cause the observed trend. We find that variations in bottom boundary temperature alone
cannot explain the span of surface temperatures and salinities measured at the Main Endeavour Field.
Heterogeneous permeability within layer 2A that has higher overall permeability in the northern part of
the vent field than the southern part can reproduce the observed north to south temperature gradient, but
such a permeability distribution cannot reproduce the observed salinity gradient. We conclude that both
deep-seated heterogeneous permeability, perhaps localized by a fault zone, and a heterogeneous layer 2A
are required to produce the trend of temperatures and salinities in vent fluids at the Main Endeavour Field
prior to the 1999 event.

- by Robert Lowell and +1
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- Two Phase Flow, Numerical Modelling, Hydrothermal systems, Mid Ocean Ridge

Reinjection of cooled geothermal fluid after extraction of heat is a common practice in order to maintain the geothermal reservoir pressure, which gradually declines due to continuous extraction of geothermal fluid. Reinjection of geothermal fluid into the geothermal reservoir ensures its safe disposal and enhances the heat recovery the efficiency of the geothermal reservoir for extracting heat energy. But since the injected geothermal fluid is cooler than the geothermal reservoir it generates a cold front near the injection well which propagates through the reservoir domain. Heterogeneity of the geothermal aquifer is also an important factor to consider since homogeneous medium is practically very rare in nature and the thermo-hydrogeological properties of the medium varies in an aquifer. The present study deals with the modeling of the transient temperature distribution in a heterogeneous geothermal reservoir in response to injection of cold geothermal water. The heterogeneous geothermal aquifer considered here is a confined aquifer with homogeneous layers of finite length and overlain and underlain by impermeable rock media. All the different layers in the aquifer and the overlying and underlying rocks are of different thermo-hydrogeological properties. The numerical modeling for the transient temperature distribution in the porous aquifer is modeled here using a software code DuMux. The heat transport modes considered are the advection, conduction and the heat loss to the confining rock media. Results show that heterogeneity plays a very significant role in determining the transient temperature distribution and controlling the advancement of the thermal front in the reservoir. The numerical model developed here is validated in this study using an analytical model. Temperature distribution derived by both methods match with each other quite well.

- by Hamid Nick
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- Geothermal, Geothermal Energy, Geothermal Reservoir, Geothermics