Thèses : « Geothermal resource »

1

Atmaca, Ilker. « Resource Assessment In Aydin-pamukoren Geothermal Field ». Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611948/index.pdf.

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Reasons like increases in the price and demand of energy in the last years, growing interest and support in the renewable energy resources, development of social environmental consciousness, interest in using domestic resources, having legal regulations has promoted the interest in the electricity production from geothermal energy. For the effective and productive use of existing resources, important data of geothermal regions are obtained with well tests. Well tests are the studies which starts while the well is drilling, continues after the well completion during the process of operation planning with optimum performance suitable to geothermal source and presents continuation also in the operation stage as required for the dynamic structure of geothermal systems. In Aydin Kuyucak Pamukö
ren region three wells are drilled, achieved results are positive. At AP1 well only CO2 emission is present, no test is done for this well. With the tests for AP2 and AP3 wells temperature, pressure and production values are determined. By the results of these tests, it is determined that this region will be one of the important fields in the West Anatolian Region with current temperature and production rate. In this study, the geothermal energy recoverable from this region is calculated with volume method of geothermal resource assessment. Monte Carlo simulation technique is used with an add-in software program @RISK to Microsoft EXCEL. Electrical power capacity of Aydin-Pamukö
ren geothermal field is determined as 45.2 MW with 90 % probability. The most likely electrical power value was found to be 78.75 MW with a probability of 69 %. The number of wells required are 10 for a production capacity of 200 t/hr and 7 for a production capacity of 300 t/hr at each well head.

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2

Yudi, Rahayudin. « Clarification of geochemical properties and flow system of geothermal fluids around the Bandung basin for geothermal-resource assessment ». Kyoto University, 2020. http://hdl.handle.net/2433/253497.

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3

Patel, Iti Harshad. « Optimal Heat Extraction for Geothermal Energy Applications ». The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1462460957.

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4

Avsar, Ozgur. « Geochemical Evaluation And Conceptual Modeling Of Edremit Geothermal Field ». Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612903/index.pdf.

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Edremit geothermal field with 42-62 °
C discharge temperatures is utilized for space heating. Alternation of permeable and impermeable units created two superimposed aquifers in the area: upper unconfined and lower confined. Water samples from 21 (hot, warm, cold) wells were taken in this study. 8 of these wells penetrate the deeper confined, while 13 penetrate the shallower unconfined aquifer. Geochemical analysis revealed Na+K&ndash
SO4 nature for the hot (>
40°
C), Ca&ndash
HCO3 nature for the cold (<
30°
C) and Ca&ndash
SO4 nature for the warm (30-40°
C) waters. &delta
18O-&delta
D compositions point to a meteoric origin for all waters, while 14C analyses suggest longer subsurface residence times for the hot, compared to the cold/warm waters. Chemical and isotopic compositions indicate that &ldquo
mixing&rdquo
and &ldquo
water-rock interaction&rdquo
are the possible subsurface processes. When silica and cation geothermometers are evaluated together with fluid mineral equilibria calculations, a 110°
C reservoir temperature is expected in the field. Saturation indices indicate potential silica scaling for waters at temperatures lower than discharge temperatures. Hydrogeology of the study area is highly affected by faults. The groundwater is percolated (down to 3 km depth) via deep seated step faults, heated at depth and ascends to surface at the low lands, especially through intersection of buried, mid-graben faults. During its ascent towards surface, geothermal water invades the two superimposed aquifers and mixing between hot and cold waters takes place in the aquifers. Resource assessment studies suggest a 3.45x1013 kJ accessible resource base and 9.1 MWt recoverable heat energy for Edremit geothermal field with 90% probability.

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5

Tian, Bingwei. « Geothermal resource assessment in shallow crust of Japan by three-dimensional temperature modeling using satellite imagery and well-logging dataset ». 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199293.

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6

Grimaldi, David Andres. « Dissolved Gases and a Carbon Dioxide Balance from the San Vicente Geothermal Fieldin El Salvador, Central America ». Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1615276127141058.

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7

Arkan, Serkan. « Assessment Of Low Temperature Geothermal Resources ». Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/1122662/index.pdf.

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One of the most applicable methods of low-temperature geothermal resource assessment is volumetric method. While applying volumetric method, the values of uncertain parameters should be determined. An add-in software program to Microsoft EXCEL, @RISK, is used as a tool to define the uncertainties of the parameters in volumetric equation. In this study, Monte Carlo simulation technique is used as the probabilistic approach for the assessment of lowtemperature Balç
ova-Narlidere geothermal field. Although Balç
ova-Narlidere geothermal field is being utilized for several direct heat applications, there exists limited data for resource assessment calculations. Assessment studies using triangular and uniform distribution type functions for each parameter gave the mean values of recoverable heat energy of the field as 25.1 MWt and 27.6 MWt, respectively. As optimistic values (90%), those values were found as 43.6 MWt and 54.3 MWt. While calculating these numbers, a project life of 25 years with a load factor of 50% is used.

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8

Budak, Barış İlken Zafer. « Resevoir Simulation of Balçova Geothermal Field/ ». [s.l.] : [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/makinamuh/T000483.doc.

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9

Kimball, Sarah. « Favourability map of British Columbia geothermal resources ». Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/29490.

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British Columbia’s internal demand for power and demand from export operations is increasing the need for power generation in the province. Moreover, the transition to a low carbon economy stipulates that power supply must be from renewable and low emission sources. Geothermal energy offers significant benefits to British Columbia which hosts Canada’s best geothermal resources associated with the Pacific Ring of Fire along the Coast Mountain Range. The objective of this work was to visualize and compare the spatial distribution of geothermal resources, transmission infrastructure, and power markets in BC. Using ArcGIS, these factors were combined into a map identifying the most favourable regions for geothermal development in the province. Multi-criteria evaluation of 10 evidence layers was completed in a knowledge-driven model. Publicly available data for temperature gradient, heat flow, volcanic centers, geothermometry, hot springs, geology, faults, and earthquake indicators comprised the resource factor map. Evidence layers in the market and infrastructure factor map included: distance to transmission, regional pricing, and population density. Evidence layers were assigned weights based on a judgment of their importance to geothermal favourability using the Analytical Hierarchy Process. The favourability map builds on the 1992 Geothermal Resources Map of British Columbia by incorporating new data, and applying spatial buffers based on studies from producing geothermal fields from around the world. The research has demonstrated how economic and infrastructure factors can be integrated into the evaluation of a region’s geothermal resources.

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10

Savage, Shannon Lea. « Mapping changes in Yellowstone's geothermal areas ». Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/savage/SavageS0809.pdf.

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Yellowstone National Park (YNP) contains the world's largest concentration of geothermal features, and is legally mandated to protect and monitor these natural features. Remote sensing is a component of the current geothermal monitoring plan. Landsat satellite data have a substantial historical archive and will be collected into the future, making it the only available thermal imagery for historical analysis and long-term monitoring of geothermal areas in the entirety of YNP. Landsat imagery from Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) sensors was explored as a tool for mapping geothermal heat flux and geothermally active areas within YNP and to develop a change analysis technique for scientists to utilize with additional Landsat data available from 1978 through the foreseeable future. Terrestrial emittance and estimates of geothermal heat flux were calculated for the entirety of YNP with two Landsat images from 2007 (TM) and 2002 (ETM+). Terrestrial emittance for fourteen summer dates from 1986 to 2007 was calculated for defined geothermal areas and utilized in a change analysis. Spatial and temporal change trajectories of terrestrial emittance were examined. Trajectories of locations with known change events were also examined. Relationships between the temporal clusters and spatial groupings and several change vectors (distance to geologic faults, distance to large water bodies, and distance to earthquake swarms) were explored. Finally, TM data from 2007 were used to classify geothermally active areas inside the defined geothermal areas as well as throughout YNP and a 30-km buffer around YNP. Estimations of geothermal heat flux were inaccurate due to inherent limitations of Landsat data combined with complexities arising from the effects of solar radiation and spatial and temporal variation of vegetation, microbes, steam outflows, and other features at each geothermal area. Terrestrial emittance, however, was estimated with acceptable results. The change analysis showed a relationship between absolute difference in terrestrial emittance and earthquake swarms, with 34% of the variation explained. Accuracies for the classifications of geothermally active areas were poor, but the method used for classification, random forest, could be a suitable method given higher resolution thermal imagery and better reference data.

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11

García, Alcaraz María del Mar. « GIS platform for management of shallow geothermal resources ». Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/393738.

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This thesis promotes an efficient use of shallow geothermal energy by means of an integrated management system to organize its exploitation. Shallow geothermal energy is a renewable resource based on thermal energy exchange with the ground. Due to the growth in demand for this energy, the development of management techniques to organize the exploitation of this resource is mandatory to protect both groundwater and the users' rights. Shallow geothermal performance of underground is closely related to groundwater behavior, so it is necessary to understand and improve the knowledge about it. Thus, an integrated methodology is proposed for the 3D visualization of underground resources related to groundwater. A set of tools named HEROS3D was developed in a GIS environment to support the generation of 3D entities representing geological, hydrogeological, hydrochemical and geothermal features. The GIS technology also gives a wide-ranging support to environmental modeling, either conceptual or numerical, especially to groundwater modeling. However, there is a scarcity of tools to implement the conceptual model in numerical modeling platforms. This transition needs of specific methodologies to adapt the geometries and alpha-numerical data from the conceptual model to the numerical model to get optimal numerical results. Although most necessities can be satisfied with inherent GIS tools, there are particular steps in the implementation of hydrogeological conceptual model into the numerical modeling software that have not been solved yet. To overcome this gap, a set of tools is presented, named ArcArAz. It focuses on the configuration of geometry and parameterization for groundwater numerical models. Once both the hydrogeological conceptual model and the numerical model are defined, a solid basis for management of Shallow Geothermal energy is available. This thesis proposes two methodologies for the management of this energy resource at two different scales: for a regional scale and for a metropolitan scale. The first GIS methodology provides a response to the need for a regional quantification of the geothermal potential that can be extracted by Boreholes Heat Exchangers and its associated environmental impacts. For the first time, advection and dispersion heat transport mechanisms and the temporal evolution from the start of operation of the BHE are considered in the regional estimation of the variables of interest. A sensitivity analysis leads to the conclusion that the consideration of dispersion effects and temporal evolution of the exploitation prevent significant differences up to a factor 2.5 in the heat exchange rate accuracy and up to several orders of magnitude in the impacts generated. To deepen the management of Shallow Geothermal Energy, this thesis proposes to establish a market of shallow geothermal energy use rights which would allow managing this resource at a metropolitan scale. This methodology is based on a GIS framework and is composed of a geospatial database to store the main information required to manage the installations and a set of GIS tools used to define, implant and control this use rights market. Thermal impacts derived from the exploitation of this resource can also be registered geographically, by taking into account the groundwater flow direction and adjusting the thermal impact to the available plot.
Esta tesis promueve el uso eficiente de la geotermia somera a través de un sistema integrado de gestión de este recurso. La geotermia somera es un recurso renovable que se basa en el intercambio de energía con el suelo. Los Intercambiadores de calor, o Borehole Heat Exchangers (BHEs) se están popularizando como sistema para explotarla. Debido al crecimiento en la demanda de geotermia somera, es imprescindible establecer una gestión integrada de este recurso para organizar su explotación y proteger tanto a las aguas subterráneas como a los beneficiarios de esta energía renovable. Debido a que la geotermia somera está íntimamente relacionada con el comportamiento de las aguas subterráneas, es imprescindible ahondar y mejorar su conocimiento. Para ello, se propone una metodología para la visualización tridimensional de los recursos subterráneos relacionados con la hidrogeología. Se ha desarrollado un conjunto de herramientas, llamado HEROS3D, en un entorno SIG. Estas herramientas facilitan la creación de entidades tridimensionales que representan datos geológicos, hidrogeológicos, hidrogeoquímicos y geotermales. Están relacionadas con una base de datos donde tanto la información bruta como la interpretada se encuentran almacenadas. La tecnología SIG también da soporte, no sólo a la modelación conceptual, sino también a la numérica, especialmente en el caso de la hidrogeología. Para facilitar la implementación de los modelos conceptuales en las plataformas de modelación numérica, esta tesis presenta un segundo conjunto de herramientas llamado ArcArAz. Estas herramientas ofrecen soluciones a los problemas más comunes relacionados con la configuración de la geometría de entrada al modelo numérico, así como su parametrización. Las bases para una gestión eficiente de la geotermia somera se establecen llamado ArcArAz. Estas herramientas ofrecen soluciones a los problemas más comunes relacionados con la configuración de la geometría de entrada al modelo numérico, así como su parametrización. Las bases para una gestión eficiente de la geotermia somera se establecen una vez que hemos definido y están disponibles tanto el modelo hidrogeológico conceptual como el modelo numérico. En relación a este aspecto, en esta tesis se proponen dos metodologías de gestión enfocadas a escalas diferentes: escala regional y escala metropolitana o local. La primera metodología SIG ofrece una respuesta a la necesidad de una cuantificación regional del potencial geotérmico somero que puede extraerse con intercambiadores de calor o Borehole Heat Exchangers, así como sus impactos térmicos asociados. Por primera vez pueden tenerse en cuenta en la estimación regional de las variables de interés la advección y dispersión de calor, como mecanismos de transporte de calor, así como la evolución temporal desde el inicio de la explotación. Un análisis de sensibilidad demuestra que la consideración de los efectos de dispersión así como el régimen temporal de la explotación supone diferencias de hasta 2.5 veces el potencial extraído y hasta de varios ordenes de magnitud en los impactos térmicos generados. Para profundizar en la gestión de la geotermia somera a escala local, esta tesis propone establecer un mercado de derechos de uso de este recurso. Esta metodología se ha implementado en un ambiente SIG y está compuesta de una base de datos donde se almacena la información principal necesaria para gestionar las instalaciones y de un conjunto de herramientas para definir, implantar y controlar este mercado de derechos de uso de geotermia somera. Los impactos térmicos derivados de la explotación de este recurso pueden quedar registrados geográficamente, teniendo en cuenta la dirección de flujo de las aguas subterráneas y ajustando estos impactos a la superficie de la parcela disponible una vez que hemos definido y están disponibles tanto el modelo hidrogeológico conceptual como el modelo numérico. En relación a este aspecto, en esta tesis se proponen dos metodologías de gestión enfocadas a escalas diferentes: escala regional y escala metropolitana o local. La primera metodología SIG ofrece una respuesta a la necesidad de una cuantificación regional del potencial geotérmico somero que puede extraerse con intercambiadores de calor o Borehole Heat Exchangers, así como sus impactos térmicos asociados. Por primera vez pueden tenerse en cuenta en la estimación regional de las variables de interés la advección y dispersión de calor, como mecanismos de transporte de calor, así como la evolución temporal desde el inicio de la explotación. Un análisis de sensibilidad demuestra que la consideración de los efectos de dispersión así como el régimen temporal de la explotación supone diferencias de hasta 2.5 veces el potencial extraído y hasta de varios ordenes de magnitud en los impactos térmicos generados. Para profundizar en la gestión de la geotermia somera a escala local, esta tesis propone establecer un mercado de derechos de uso de este recurso. Esta metodología se ha implementado en un ambiente SIG y está compuesta de una base de datos donde se almacena la información principal necesaria para gestionar las instalaciones y de un conjunto de herramientas para definir, implantar y controlar este mercado de derechos de uso de geotermia somera. Los impactos térmicos derivados de la explotación de este recurso pueden quedar registrados geográficamente, teniendo en cuenta la dirección de flujo de las aguas subterráneas y ajustando estos impactos a la superficie de la parcela disponible

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12

Kitsou, Olga 1973. « Power generation from geothermal resources : challenges and opportunities ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/38199.

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Thesis (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
Includes bibliographical references (leaves 73-79).
As we enter the 21st century, increasing concerns about global warming have stimulated an upsurge of interest in the use of non-fossil energy technologies for electricity production. As a result there is an opportunity for expansion of geothermal resource development. This thesis examines power generation technology for two distinct categories of geothermal resources: Hydrothermal and Hot Dry Rock (HDR). The thesis assesses growth opportunities for, and challenges to, the full deployment of geothermal power systems in the electricity market. It analyzes the key impediments that - have and will affect the attractiveness of geothermal technologies, describes policy measures that can be adopted to overcome these impediments, and draws conclusions and recommendations for R&D on geothermal systems.
by Olga Kitsou.
S.M.

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13

Ackerman, Galena Gene. « Biogeochemical gradients and energetics in geothermal systems of Yellowstone National Park ». Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/ackerman/AckermanG1206.pdf.

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14

İnce, Umut Güden Mustafa. « A case study of material testing for corrosion in low temperature geothermal systems/ ». [s.l.] : [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/malzemebilimivemuh/T000387.pdf.

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15

Ozkaya, Melike. « Numerical Modeling Of Kizildere Geothermal Field ». Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609142/index.pdf.

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This research is dedicated to make a foreseeing of the future state of the Kizildere Geothermal Field in order to suggest acceptable solutions to the current problems. The non-isothermal mechanism of the geothermal field is simulated for the pressure and temperature variables. For this purpose, a finite element model (696 four-nodal elements with 750 nodes) of the field is formulated by considering the geological conditions and the present wells already drilled in the area. Then the model is calibrated to the field for the natural state by using appropriate physical properties, boundary and initial conditions. Comparison of the simulated and the observed pressures and temperatures has emphasized a very successful calibration study. After the calibration, response of the field to the production and injection for the period of 1984-2006 has been simulated by applying a history matching study. History matching runs have yielded very good correlations between the observed and the computed values of the pressure and temperature variables. The calibrated and history matched model has been applied to the field to simulate the future performance of the field for different production and injection scenarios. In the first scenario the field is simulated for the next 10-year production period keeping the on-going production conditions. Then, the influence of the production of two new wells has been investigated in two different scenarios. In the forth scenario, the effect of injection from one of the production wells has been simulated.

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16

McIver, Donald A. « Epithermal precious metal deposits physicochemical constraints, classification characteristics and exploration guidelines ». Thesis, Rhodes University, 1997. http://hdl.handle.net/10962/d1005553.

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Epithermal deposits include a broad range of precious metal, base metal, mercury, and stibnite deposits. These deposits exhibit a low temperature of formation (180-280°C) at pressures of less than a few hundred bars (equivalent to depths of 1.5 - 2.0lkm). Epithermal gold deposits are the product of large-scale hydrothermal systems which mostly occur in convergent plate margin settings. Associated volcanism is largely of andesitic arc (calcalkaline to alkaline), or rhyolitic back-arc type. Porphyry Cu-Mo-Au deposits form deeper in the same systems. Genetic processes within individual deposits take place in an extremely complex manner. The resultant mineral associations, alteration styles and metal deposition patterns are even more complicated. Many attempts have been made to classify epithermal deposits based on mineralogy and alteration, host rocks, deposit form, genetic models, and standard deposits. For the explorationist, the most useful classification schemes should be brief, simple, descriptive, observationally based, and informative. Ultimately, two distinct styles of epithermal gold deposits are readily recognised: high-sulphidation, acid sulphate and low-sulphidation, adularia-sericite types. The terms high-sulphidation (HS) and low-sulphidation (IS) are based on the sulphidation state of associated sulphide minerals, which, along with characteristic hydrothermal alteration, reflect fundamental chemical differences in the epithermal environment. Highsulphidation-type deposits form in the root zones of volcanic domes from acid waters that contain residual magmatic volatiles. The low-sulphidation-type deposits form in geothermal systems where surficial waters mix with deeper, heated saline waters in a lateral flow regime, where neutral to weakly acidic, alkali chloride waters are dominant. The HSILS classification, combined with a simple description of the form of the deposit, conveys a large amount of information on mineralogy, alteration, and spatial characteristics of the mineralisation, and allows inferences to be drawn regarding likely regional controls, and the characteristics of the ore-forming fluids. The modern understanding of these environments allows us to quite effectively identify the most probable foci of mineral deposition in any given district. Current knowledge of these deposits has been derived from studies of active geothermal systems. Through comparison with alteration zones within these systems, the exploration geologist may determine the potential distribution and types of ore in a fossil geothermal system. Alteration zoning specifically can be used as a guide towards the most prospective part of the system. Epithermal gold deposits of both HS- and LS-styles are nevertheless profoundly difficult exploration targets. Successful exploration must rely on the integration of a variety of exploration techniques, guided by an understanding of the characteristics of the deposits and the processes that form them. There are no simple formulae for success in epithermal exploration: what works best must be determined for each terrain and each prospect. On a regional scale tectonic, igneous and structural settings can be used, together with assessment of the depth of erosion, to select areas for project area scale exploration. Integrated geological-geophysical interpretation derived from airborne geophysics providesa basis of targeting potential ore environments for follow-up. Geology, geochemistry and surface geophysics localise mineral concentrations within these target areas

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17

Sigfússon, Bergur. « Reactive transport of arsenic through basaltic porous media ». Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=103575.

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This thesis studied the volcanic and geothermal source of arsenic (As) and its fate in shallow ground waters and upon entering the ocean by means of experimental and field measurements combined with geochemical modeling. Arsenic enters the atmosphere and hydrosphere from degassing magmas and during volcanic eruptions. The November 2004 eruption within the Vatnajökull Glacier, Iceland, provided an opportunity to study elemental fluxes from volcanic eruptions into the environment. According to geochemical modeling, lowering of pH due to magma gases during the eruption led to rapid tephra dissolution with corresponding change in flood water chemistry. Geochemical modeling of floodwater/seawater mixing indicated localised decrease in dissolved arsenic and sulphur due to adsorption on the suspended floodwater materials. As the floodwater was diluted the As desorbed and limited effect of the floodwater was predicted after thousand fold dilution. Laboratory experiments were carried out to generate and validate sorption coefficients for arsenite and arsenate in contact with basaltic glass at pH 3 to 10. The mobility of arsenite decreased with increasing pH. The opposite was true for arsenate, being nearly immobile at pH 3 to being highly mobile at pH 10. A 1D reactive transport model constrained by a long time series of field measurements of chemical composition of geothermal effluent fluids from a powerplant was constructed. Thioarsenic species were the dominant form of dissolved As in the waters exiting the power plant but converted to some extent to arsenite and arsenate before feeding into a basaltic lava field. Chloride, moved through the basaltic lava field (4100 m) in less than 10 yrs but arsenate was retarded considerably due to surface reactions and has entered a groundwater well 850 m down the flow path in accordance to prediction by the 1D model, which further predicted a complete breakthrough of arsenate in the year 2100 while arsenite will be retained for about 1000 yrs.

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18

Huebner, Laura E. « Investigations of the Steamboat Hills geothermal reservoir beneath the University of Nevada, Reno's Redfield campus using shallow geophysical techniques / ». abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1461543.

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Thesis (M.S.)--University of Nevada, Reno, 2008.
"December, 2008." Includes bibliographical references (leaves 82-85). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

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19

Kennedy, Kevin. « Dikewater Relationships to Potential Geothermal Resources on Leeward West Maui, State of Hawaii ». Thesis, University of Hawaii at Manoa, 1985. http://hdl.handle.net/10125/21688.

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20

St, John Anna Maria. « Hydrogeochemical Characterization of the Alvord Valley Known Geothermal Resources Area, Harney County, Oregon ». PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/2678.

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The Alvord Valley Known Geothermal Resources Area (KGRA) , located east of the Steens Mountain-Pueblo Mountains fault block in southeastern Oregon, is within the northern Basin and Range province. This investigation focuses on three thermal areas in the Alvord Basin: Borax Lake and the hot springs north of Borax Lake, Alvord Hot Springs and Mickey Springs. Mickey Springs and the springs north of Borax Lake are boiling at the surface (94 and 95° C, respectively). Inflow temperatures to Borax Lake, measured at a depth of 30 m, are greater than 100° C. Surface temperatures for Alvord Hot Springs and a flowing well northeast of Borax Lake are 78 and 59° C, respectively. Thermal fluids issue from Quaternary lacustrine and alluvial deposits. While silica sinter deposits are present at all three thermal areas, sinter is not presently being deposited. Minor calcite is being deposited at the springs north of Borax Lake. The springs discharge from N to NEstriking, high-angle, basin-bounding faults along the base of Steens Mountain and Mickey Mountain and NE-striking intrabasinal faults south of Alvord Lake. The thermal waters are dilute sodium-bicarbonate waters with significant amounts of sulfate and chloride. Conservative element plots (B, F, and Li vs. Cl) indicate good correlation between Cl and the other conservative elements. These correlations could result from mixing of thermal water with a dilute cold water or fluid evolution due to increased fluid-rock interaction, evaporation, and steam loss due to boiling. The small variations in chloride concentrations of thermal fluids during the sampling period argues against mixing of thermal fluids with cold water. The geothermal system is a hot-water rather than a vapordominated system. The ỎD content of thermal fluids is similar to the ỎD content of local cold water wells, springs, basinal pore fluids at a depth of 4 to 5 m, and perennial streams. Similarities in ỎD values indicate recharge for geothermal fluids is precipitation from the Steens Mountain fault block. The Ỏ18 content of thermal fluids is shifted 2 to 3°/oo to the right of the world meteoric water line indicating fluid-rock interaction at elevated temperatures in the reservoir. Tritium contents indicate relatively long residence times and/or low-velocity circulation of meteoric water through basement rocks. Values range from 0 to 0.25 T.U. The application of two end-member models, which calculate fluid residence times, generate a minimum of 57 years and a maximum of greater than 10,000 years. Estimated reservoir temperatures based on cation and silica geothermometry are between 170 and 200°C. Oxygensulfate isotope geothermometer estimates indicate reservoir temperatures between 198 and 207' C for Borax Lake and Alvord Hot Springs. Mickey Springs and a flowing well northeast of Borax Lake yield temperature estimates of 168 and 150° C, respectively. These values indicate partial reequilibration of the isotopic system. The Ỏ13C contents of carbon dioxide and methane of gas discharges from the thermal areas are similar to geothermal fluids from other sites. The Ỏ13C of methane indicate "normal" geothermal methane for Alvord Hot Springs and Mickey Springs (-27.8 and -27.6, respectively). The Ỏ13C of CH4 for springs north of Borax Lake (-33.6) indicates a small amount of thermogenic methane may be contributed by thermal alteration of organics in basinal sediments. The Ỏ13C contents for C02 at Alvord Hot Springs and Borax Lake are within the range expected for atmospheric, fumarolic, or mantle derived C02 (-6.5 and -6.6, respectively). The Ỏ13C content of C02 from Mickey Springs is isotopically lighter than gas released from fumaroles or the mantle (-9.4). N2/Ar ratios for Mickey Springs and Borax Lake gases (39.2 and 40.8, respectively) indicate interaction with airsaturated ground water during flow through the the zone of aeration. Helium is enriched relative to Ar and N2 in gas discharges from Alvord Hot Springs, indicating longer fluid residence times and/or increased crustal interaction at high temperatures. Ratios of B/Cl indicate the fluid reservoir is hosted in volcanic rocks. The Li/Cs ratios for the Borax Lake thermal area are consistent with a reservoir located in rhyoli tic rocks. The 228Ra/226Ra content of Borax Lake thermal fluids (1.14 ± 0.13 dpm/kg) indicates interaction with volcanic rocks for Borax Lake. The 228Ra/226Ra content of thermal fluids from Alvord Hot Springs and Mickey Springs (0.38~0.02 and 0.17 ~ 0.09) are lower than those expected for volcanic rocks and may indicate local uranium accumulation in the reservoir or zones of upflow. The 87Sr / 86Sr values for thermal waters and stratigraphic uni ts indicate the fluid reservoir is located in volcanic rocks beneath Steens Basalt. Equilibration of fluids in these units argues for thermal water circulation depths of 2 to 2.5 km in the Borax Lake thermal area, greater than 3 km in the Alvord Hot Springs area and 1 to 2 km in the Mickey Springs area. Data presented in this study do not preclude a single large deep reservoir system discharging at these three thermal areas in the Alvord basin. Differences in the chemical and isotopic composition of discharge from the three thermal areas are produced during upf low from the reservoir. During upflow, thermal waters follow a complex pathway of vertical and lateral fractures which includes short residence times in shallow reservoirs before reaching the surface. Boiling, mixing with condensate, oxidation, mixing with 1-3% tritium-bearing, near-surface cold water, relative differences in flow rate and volume, and slow cooling without vigorous boiling are processes that modify fluid composition during upflow from the deep geothermal reservoir.

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Vice, Garrett S. « Structural controls of the Astor Pass-Terraced Hills geothermal system in a region of strain transfer in the western Great Basin, northwestern Nevada ». abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1456425.

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PASQUA, CLAUDIO. « Advances in the Exploration of Geothermal Resources of the East Africa Rift System (EARS) ». Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/945511.

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This work focuses on the geological, geophysical and geochemical exploration of the geothermal reservoirs located in the East Africa Rift System (EARS), with particular reference to the characterisation of some geothermal fields located in Ethiopia, Kenya, Tanzania and Malawi. Moreover, this study provides an updated overview of the procedures for the exploration of geothermal resources and can serve therefore as a best-practice guide for future endeavours. Field activities included geological surveys, geophysical investigations (gravity, electromagnetic and seismic measurements) and geochemical survey/analyses. Moreover, stratigraphic data and P&T logs were available at some explored geothermal prospects. An overview of the main investigated geothermal fields was given and three case studies were described in detail as representative examples of geothermal play types of EARS: (i) the Alalobeda field (Ethiopia), located in correspondence of the triple junction Read Sea-Aden Gulf-Main Ethiopian Rift and (ii) the Kiejo-Mbaka field (Tanzania), belonging to EARS’ western branch, both falling in the extensional domain play type, fault controlled or fault-leakage controlled; (iii) the Menengai field (Kenya), the second most important geothermal field in EARS, where a huge quantity of direct data from more than twenty drilled wells is available. The latter can be classified as convection-dominated magmatic play type. Compared to geothermal fields of South-East Asia and Central America, the geothermal of EARS presents some peculiar characters and differences. The plutonic play-type (convection dominated), occurring in fore- or back-arc regions of fold-thrust belts along subduction zones, denotes a well-developed thick and continuous cap rock mainly formed by clay minerals. In the plutonic play of Menengai, the typical impermeable cap rock is practically missing. A “zonation” of the play types occurring in EARS can be recognized. The Western Branch is characterised by the presence of fault/fault-leakage controlled play types. In the Eastern Branch, geothermal plays are associated to active or quite recent volcanoes. Due to the foregoing characters, a different approach should be followed in order to characterize properly the geothermal fields present in EARS. In a subduction context, geophysical results from electromagnetic investigations play a fundamental role in the exploration of potential geothermal reservoirs, as in such an environment they are often succesfully used to detect the occurrence of an impermeable cap rock overlying the reservoir (target zone). Therefore, if the resistivity structures inferred in EARS geothermal plays are simply associated with “standard” resistivity models of cap rock-reservoir formations, the inferred geophysical conceptual model may be grossly incorrect. Wherefore, an accurate and integrated interpretation of all the geoscientific data is essential. In this regard, a detailed structural survey is of primary importance especially in the fault-controlled plays, whereas its importance is often under-estimated in subduction realms. A high-resolution structural survey allows to define a detailed configuration of fractures and faults that may control the fluid upflow from the reservoir. Concerning the application of geochemical methods, in EARS, typical approaches and models developed in the subduction geothermal systems should be re-evaluated. The high-temperature geothermal reservoirs of the Eastern branch (e.g., Olkaria and Menengai in Kenya, and Aluto-Langano in Ethiopia) host not only mature chloride waters, as the geothermal systems situated along subduction zones, but also mature bicarbonate-chloride and mature bicarbonate waters. In volcanic-magmatic regions, deep geothermal liquids are assumed to be produced through neutralization of initially acidic meteoric-magmatic aqueous solutions. The few available data for volcanic gases indicate that subduction zones volcanic gases are enriched in Cl relative to hot-spot and divergent-plate volcanic gases. Therefore, the comparatively small supply of Cl-bearing magmatic gas species (chiefly HCl) in the root of the Eastern EARS geothermal systems might be responsible for the comparatively low Cl contents of related geothermal liquids. The situation might be even more complicated in the western EARS, due to the absence of magmatic systems. Therefore, a more comprehensive approach to water classification is needed to distinguish mature waters from immature ones. In view of the differences with the geothermal systems hosted in subduction zone environments, the future exploration and development of geothermal resources of EARS should thus consider that geothermal resources are rarely due to the presence of a hot magmatic source, but rather to the crustal thinning, which determines thermal anomalies of moderate intensity. Moreover, favorable thermal conditions are not always accompanied by an adequate hydrogeological setting, expecially when they occur in low permeability basalts. In these cases, it is essential to pay attention to the structural setting, in order to design the wells with the highest likelihood of intersecting permeable tectonic structures. Unlike in most Indonesian fields, where permeability tends to be widespread throughout the rock, in the EARS permeability appears in many cases limited to major faults. The planned program of drilling in several prospects of Ethiopia and Tanzania will make available further information improving the overall understanding of the geothermal characteristics of EARS.

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Dur, Fatih Çelik H. Murat. « The Usage Of Stochastic And Multicriteria Decision-Aid Methods Evaluating Geothermal Energy Exploitation Projects/ ». [s.l.] : [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/sehirplanlama/T000324.pdf.

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Thesis (Master)--İzmir Institute of Technology, İzmir, 2005.
Keywords: Geothermal energy, multi criteria decision method, stochastic methods, Monte Carlo method. Includes bibliographical references (leaves.93-98).

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Hull, Carter Dean. « Multicomponent chemical equilibrium modeling of the fluids and U-TH geochrnology of authigenic mineralization in geothermal systems / ». View full-text version online through Crater Lake Digital Research Collection, 1990. http://craterlakelib.oit.edu/u?/craterlake,144.

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Thesis (Ph. D.)--University of Oregon, 1990.
Typescript (photocopy). Presented to the Department of Geological Sciences and the Graduate School of the University of Oregon in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Includes bibliographical references (leaves 157-164).

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Alshareef, Ahmed Shehab. « Technology Assessment Model of Developing Geothermal Energy Resources for Supporting Electrical System : the Case for Oregon ». PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3515.

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The demand for energy is increasing worldwide. All applications contributed to increase the demand of all energy industry, and therefore the effect on the environment and the rise in pollution increased significantly. This is considered a large problem, and researchers focused their research on renewable energy for reducing the cost of energy in the future. Geothermal energy has significant impact as a source of electricity generation since it will not harm the environment. There are more than twenty countries that benefit from geothermal plants, which generate more than 6000 megawatts .Three alternatives of geothermal energy technology (GHP, Direct use of Geothermal Heat, and Geothermal Electricity) can be used for supporting electrical systems in Oregon. At the same time, the success of using the geothermal energy alternatives in Oregon relies on different goals for achieving the best geothermal development. Oregon has been ranked third in the potential use of geothermal energy after Nevada and California. The objective from the research study was to develop an assessment model framework that can be used for supporting cost effective renewable energy in Oregon by the development of geothermal energy sources. This research of study was done by using the Hierarchical Decision Model (HDM) and consisted of four levels: Mission, objectives, goals, and alternative. Criteria used in this research study are based on five objectives to know what are the most important factors in the decision-making process. These objectives are: social, environmental, economical, technical, and political. The decision model connected objectives, goals, and alternative for obtaining the accurate decision. HDM used for this purpose to analyze the result of data collected from experts. Seven experts who had experience in the geothermal field participated in this research study, and they gave their judgment in the questionnaire survey link by using pair-wise comparison method. The outcome analysis of the results showed that in terms of objectives that Minimizing Environmental Impact was rated at the highest value at 0.26 with respect to the mission. Within the category of Minimizing Environmental Impact, Seismic Activity and GHG Emissions had higher values. The results show that "Geothermal Electricity," with a rating of 43%, was ranked as the most important alternative with respect to mission, objectives, and goals. "Direct Use of Geothermal Heat" was ranked as the second most important alternative with 31%. The results of this research study were discussed with the experts to get their feedback, and learn from them what requirements are necessary for improvement in the geotechnical energy sector for future research. The experts agreed that this methodology is a good approach to help reach the right decision since this methodology (HDM) divides the problem into small sets, which will make the decision process easier.

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Hansson, Lina. « Concentrations and riverine massflows of geothermal arsenic. : Case study : Jemez River, NM, USA ». Thesis, Stockholms universitet, Institutionen för naturgeografi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-127418.

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Geothermal arsenic (As) and its inorganic species transformation in river systems are of global concern, since As has a potential negative impact on human health and ecosystems. Periods of increased precipitation may change As concentrations and As partitioning in streams, due to elevated water tables, increased runoff generation, dilution, and interactions with sediment.In this study we investigate hydrological conditions of Jemez River, located along the Jemez fault in NM, USA, during the monsoon months June, July and August of 2015. We aim at determining how different hydrological conditions in the Jemez River during the monsoon months might affect the concentrations and riverine mass flows of geothermally derived (total) As and As III discharging in a travertine- and hot spring area called Soda Dam. Water and sediment from the river and hot springs sites, as well as streamflow measurements along a 22 km river reach were collected. The chemical composition of water and sediment was determined using Inductively Coupled Plasma-Optical Emission Spectrometry/Mass Spectrometry (ICP-OES/MS); and Ion Chromatography (IC) as well as a High Performance Liquid Chromatograph (HPLC) coupled to an ICP-MS for further water analysis. Discharge and mass flows as well as element inputs and outputs to/from Soda Dam was computed. The measurement months were characterized by a median discharge of 1642 L/s. During the measurement campaigns peak flows occurred with discharges of 2.5×104 to 6.1×104 L/s during the measurement campaigns. Arsenic concentrations were between 1.3 and 107 μg/L in river water, between 167.3 and 6707 μg/L in hot spring waters, and between 0.37 and 13.1 μg/kg in river bed sediment. Arsenic III was found in hot springs water and river water. Infiltration and subsurface flows induced by fault-associated fractures and permeability structures were found to be likely to divert water at Soda Dam, as reflected in large discharge differences along the reach (470 to 1305 L/s). These flows also had an impact on As concentrations in riverine and hot spring water since they mobilize As from bedrock and sediment. Changing mass flows of As can only in a few cases be explained by dilution processes by Jemez River, which has previously been assumed to be the main control on As mass flows along the stretch. Instead, our findings are likely to reflect changes in chemical composition of the mixed geothermal waters discharging at Soda Dam, due to changing mixing ratios of ground waters of different compositions. The present study hence provides a refined interpretation of the hydrological pathways in Soda Dam and Jemez River, and calls for more discharge and geochemical investigations during a longer study period, to properly investigate the driving forces behind the fate of the As from geothermal fluids.

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Manente, Giovanni. « Analysis and Development of Innovative Binary Cycle Power Plants for Geothermal and Combined Geo-Solar Thermal Resources ». Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3421590.

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This thesis analyzes binary cycle power plants (Organic Rankine Cycles) for electricity generation from low enthalpy geothermal resources. The objective is the maximization of the net power output by means of the proper selection of the working fluid and cycle parameters. A critical review of many studies on ORCs in the scientific literature is carried out to provide a basis for an optimization study having the exergy recovery efficiency as objective function. Two working fluids are analyzed taking into account both supercritical and subcritical pressures and different temperatures of the geothermal fluid. The application of advanced techniques derived from Pinch Analysis (HEATSEP method) allowed finding also sub-optimal solutions, corresponding to small deviations of the cycle parameters from the optimal design values. These solutions, although sub-optimal from a thermodynamic point of view, may be selected when different aspects related to the technology, economics, flexibility or safety of the system are considered. The costs of the optimal thermodynamic solutions are estimated using the module costing technique that relates all capital and operating costs to the purchased cost of equipment evaluated for some base conditions. The economic results show the impact of the geothermal fluid temperature and working fluid selection on the economics of the system. The results of this study are applied to the Stillwater real binary cycle power plant that started operating in 2009 in Nevada (USA). The power plant operates at subcritical pressures with isobutane as working fluid and uses a dry cooling system as heat rejection system. Due to the limited geothermal resource the plant net power output is much lower than expected. A detailed off-design model of the power plant is developed using the software Aspen. The model is tested and adjusted against the plant data collected during the first year of operation. After validation, the model is run to evaluate the operating parameters that maximize the annual energy production. A study is then performed to increase the performance of Stillwater geothermal binary power plant with the addition of the solar source. The combination of the high exergy solar resource with the low exergy geothermal resource could provide many benefits such as the improvement of the thermal efficiency and the increase of the power output during the day and especially during the warm season, a time when the energy production of air-cooled geothermal power plants is markedly reduced. The addition of the solar heat in the Stillwater geothermal plant restores operating conditions close to design point also in presence of reduced geothermal flow rate and temperature. The detailed off-design model of Stillwater power plant is used to carry out this hybridization study. Cycle parameters are optimized for different values of the ambient temperature and solar irradiation in order to maximize the annual energy production. Two different designs of hybrid geo-solar plants, with and without storage, are compared, and the levelized cost of electricity (LCOE) of the incremental generation from solar energy is calculated. As expected, this LCOE is quite high due to the high costs of the solar collectors and could be competitive only in presence of appropriate incentives.
La tesi analizza gli impianti a ciclo binario (Organic Rankine Cycles) per generazione di elettricità da risorse geotermiche a bassa entalpia. L'obiettivo è la massimizzazione della potenza netta tramite una selezione appropriata del fluido operativo e dei parametri di ciclo. La valutazione critica di molti studi sui cicli di Rankine organici ha fornito le basi per formulare uno studio di ottimizzazione avente come funzione obiettivo il rendimento di recupero exergetico. Sono analizzati due fluidi operativi considerando sia pressioni supercritiche che subcritiche e diverse temperature del fluido geotermico. L'applicazione di tecniche avanzate derivate dalla Pinch Analysis (metodo HEATSEP) ha consentito di trovare anche soluzioni sub-ottimali, corrispondenti a piccoli scostamenti dei parametri di ciclo dai valori di progetto ottimali. Queste soluzioni, sebbene sub-ottimali da un punto di vista termodinamico, potrebbero essere scelte se venissero considerati anche aspetti legati alla tecnologia, economia, flessibilità o sicurezza del sistema. I costi delle soluzioni termodinamicamente ottimali sono quindi valutati mostrando l'impatto della temperatura del fluido geotermico e della scelta del fluido operativo sull'economia del sistema. I risultati di questo studio sono applicati all'impianto reale a ciclo binario di Stillwater che iniziò l'operazione nel 2009 in Nevada (USA). L'impianto opera a pressioni subcritiche con isobutano come fluido operativo e usa un sistema di raffreddamento ad aria. A causa della limitata risorsa geotermica la potenza netta prodotta dall'impianto è molto più bassa di quella attesa. E' stato sviluppato un modello dettagliato di fuori progetto dell'impianto usando il software Aspen. Il modello è stato validato con i dati dell'impianto raccolti nel primo anno di attività. Dopo validazione il modello è utilizzato per ottenere i parametri operativi che massimizzano la produzione energetica annuale. E' stato quindi effettuato uno studio per aumentare le prestazioni dell'impianto geotermico di Stillwater con l'aggiunta della risorsa solare. I parametri di ciclo sono ottimizzati per valori differenti della temperatura ambiente e della radiazione solare per massimizzare la produzione energetica annuale. Sono confrontate due configurazioni di ciclo ibrido, con e senza accumulo, ed è calcolato il costo dell'energia elettrica (LCOE). Come atteso, questo LCOE è abbastanza elevato a causa dei costi elevati dei collettori solari e potrebbe essere competitivo solo in presenza di incentivi appropriati.

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Кулдашов, О. Х. « Контроль концентрацииH[2]S, Co[2] газов в геотермальной энергетике ». Thesis, Сумский государственный университет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39874.

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В последние годы все большее внимание привлекают проблемы использования чистых нетрадиционных возобновляемых источников энергии (НВИЭ) для нужд энергоснабжения различных сельскохозяйственных и промышленных объектов. Актуальность и перспективность данного направления энергетики обусловлена двумя основными факторами: катастрофически тяжелым положением экологии и необходимостью поиска новых видов энергии.

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Ogland-Hand, Jonathan D. « Integrated Systems Analyses of Using Geologically Stored CO2 and Sedimentary Basin Geothermal Resources to Produce and Store Energy ». The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555079270508336.

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Speer, Kevin G. (Kevin George). « The influence of geothermal sources on deep ocean temperature, salinity, and flow fields ». Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/58534.

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Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1988.
Includes bibliographical references (p. 142-146).
This thesis is a study of the effect of geothermal sources on the deep circulation, temperature and salinity fields. In Chapter 1 background material is given on the strength and distribution of geothermal heating. In Chapter 2 evidence for the influence of a hydrothermal system in the rift valley of the Mid-Atlantic Ridge on nearby property fields and a model of the flow around such a heat source are presented, with an analysis of a larger-scale effect. Results of an analytical model for a heat source on a #-plane in Chapter 3 show how the response far from the source can have a structure different from the forcing because of its dependence on two parameters: a Peclet number (the ratio of horizontal advection and vertical diffusion), and a Froude-number-like parameter (the ratio of long wave phase speed to background flow speed) which control the relative amount of damping and advection of different vertical scales. The solutions emphasize the different behavior of a dynamical field like temperature compared to tracers introduced at the source. These ideas are useful for interpreting more complicated solutions from a numerical model presented in the final chapter.
by Kevin G. Speer.
Ph.D.

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Sullivan, Michael P. « Water Balance of the San Simon Groundwater Basin, El Salvador, Central America : Implications for the Berlin Geothermal Field ». Ohio : Ohio University, 2008. http://www.ohiolink.edu/etd/view.cgi?ohiou1212673612.

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Arfstrom, John David. « A model of the hydrothermal system at Casa Diablo in Long Valley, California, based on resistivity profiles and soil mercury analyses ». FIU Digital Commons, 1993. http://digitalcommons.fiu.edu/etd/1306.

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A description and model of the near-surface hydrothermal system at Casa Diablo, with its implications for the larger-scale hydrothermal system of Long Valley, California, is presented. The data include resistivity profiles with penetrations to three different depth ranges, and analyses of inorganic mercury concentrations in 144 soil samples taken over a 1.3 by 1.7 km area. Analyses of the data together with the mapping of active surface hydrothermal features (fumaroles, mudpots, etc.), has revealed that the relationship between the hydrothermal system, surface hydrothermal activity, and mercury anomalies is strongly controlled by faults and topography. There are, however, more subtle factors responsible for the location of many active and anomalous zones such as fractures, zones of high permeability, and interactions between hydrothermal and cooler groundwater. In addition, the near-surface location of the upwelling from the deep hydrothermal reservoir, which supplies the geothermal power plants at Casa Diablo and the numerous hot pools in the caldera with hydrothermal water, has been detected. The data indicate that after upwelling the hydrothermal water flows eastward at shallow depth for at least 2 km and probably continues another 10 km to the east, all the way to Lake Crowley.

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Weides, Simon [Verfasser], Inga [Akademischer Betreuer] Moeck et Wilhelm [Akademischer Betreuer] Dominik. « Exploration of geothermal resources in the Alberta Basin, Canada / Simon Weides. Gutachter : Wilhelm Dominik ; Inga Moeck. Betreuer : Inga Moeck ». Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1066163715/34.

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Nguyen, Tien Hoang. « Development of transformation method of multispectral imagery into hyperspectral imagery for detailed identification of metal and geothermal resources-related minerals ». Kyoto University, 2017. http://hdl.handle.net/2433/227611.

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Lee, Chun-kwong, et 李振光. « Computer modelling and simulation of geothermal heat pump and ground-coupled liquid desiccant air conditioning systems in sub-tropicalregions ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41290768.

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Lee, Chun-kwong. « Computer modelling and simulation of geothermal heat pump and ground-coupled liquid desiccant air conditioning systems in sub-tropical regions ». Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41290768.

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Lebedka, Serhii Mykolaiovych, Сергей Николаевич Лебедка, Сергій Миколайович Лебедка et В. А. Шаповал. « Геотермальная электроэнергетика ». Thesis, Изд-во СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/4272.

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Геотермальная энергия (природное тепло Земли), аккумулированная в первых десяти километрах Земной коры, по оценкам достигает 137 трлн. т.у.т., что в 10 раз превышает геологические ресурсы всех видов топлива вместе взятых. Анализ показывает, что из всех видов геотермальной энергии наилучшие экономические показатели имеют гидрогеотермальные ресурсы – термальные воды, пароводяные смеси и природный пар. При цитировании документа, используйте ссылку http://essuir.sumdu.edu.ua/handle/123456789/4272

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Corr, Mandi Lee. « Renewable energy in Montana system applications and technlogy / ». [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-04212009-123850/unrestricted/Mandi_Corr_Thesis.pdf.

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Dhansay, Taufeeq. « Evaluation for harnessing low-enthalpy geothermal energy in South Africa based on a model pilot plant in the Limpopo Mobile Belt ». Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1019789.

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South Africa generates more than 90 percent of its total energy capacity through non-renewable sources. With coal forming the predominant energy source, South Africa became the leading carbon emissive nation in Africa, emitting 450 million tonnes of CO2 in 2011. In an international effort to restrict global average temperature rise to 2° C above the average prior the industrial revolution, the Kyoto Protocol has been extended for another 8-year commitment period. This is complementary to an expected resolution of a new legally binding climate change policy in 2015. This policy will aim to introduce financial penalties for nations failing to meet ascribed GHG emission targets by 2020. In an attempt to meet these climate change resolutions South Africa will research and develop cleaner, alternative forms of energy, including hydro, wind, and biomass forms of renewable energy, in addition to designating stringent building regulations for the Incorporation of solar energy. These measures form part of an Integrated evelopment Plan that aims to generate a target of 10,000 GWh of renewable energy in 2013. South Africa is also investigating the possibilities of extracting its shale gas reserves and implementing it as a major energy source. This energy mix has given little attention to geothermal energy. The reasons for this omission appears to be the lack of active volcanism and previous research that suggests South Africa, largely underlain by the Kaapvaal Craton, has a relatively low heat Flow profile, deemed insufficient for harnessing geothermal energy.

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Souza, Filho Mário Nascimento 1943. « Avaliação do potencial geotérmico da bacia sedimentar de Taubaté ». [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287613.

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Orientador: Sueli Yoshinaga Pereira
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
Made available in DSpace on 2018-08-20T15:45:24Z (GMT). No. of bitstreams: 1 SouzaFilho_MarioNascimento_M.pdf: 8976577 bytes, checksum: 06f17de0e0e20fb1daea5a785d88c120 (MD5) Previous issue date: 2012
Resumo: Os recursos conhecidos de energia geotermal no Brasil são de baixa entalpia, com fontes contendo fluidos com valores de temperatura inferiores a 100ºC. Isto por si só desencoraja a tentativa de buscar cenários possíveis de aproveitamento das fontes, restritas até então, aos usos através de balneários, com o aproveitamento dos poços mais profundos perfurados inicialmente para petróleo, principalmente na Bacia do Paraná. Estudos recentes foram desenvolvidos em diversos países com vistas ao aproveitamento geotermal de bacias sedimentares, semelhantes às nossas, buscando recursos geotermais, abaixo do topo do embasamento, nos denominados HDR (Hot Dry Rock), através de injeção de fluidos que irão circular no meio rochoso fraturado (artificialmente ou não), aquecer e retornar à superfície em forma de vapor, para então serem aproveitados. Este cenário foi avaliado e estudado para um eventual aproveitamento na Bacia de Taubaté. Uma pesquisa bibliográfica foi feita focada no tema em estudo e não pretendeu esgotar o assunto, mas sim servir de ponto de partida para realizá-los. Foram tratados os perfis geofísicos de 39 poços selecionados no vale do Paraíba do Sul, entre Jacareí e Cachoeira Paulista, no Estado de São Paulo, identificadas as alternâncias litológicas, medidas as temperaturas dos poços, em construção, as espessuras dos distintos litotipos e traçados mapas de isovalores do topo do embasamento cristalino e sua temperatura. A partir desse ponto calculou-se o grau geotérmico para a área e foram traçados mapas previsionais de temperatura no horizonte 1.000 metros de profundidade sobrepostos aos mapas temáticos da distribuição percentual dos litotipos encontrados na bacia, com vistas ao aproveitamento econômico dos recursos geotermais. Duas áreas no vale do Paraíba despertaram interesse e será objeto de novas prospecções com vistas à definição do Projeto de Avaliação de Energia Geotermal na Bacia de Taubaté
Abstract: The known geothermal energy resources of Brazil have a low enthalpy level, with sources showing temperature levels lower than 100º Centigrade This fact by itself had discouraged initiatives aimed to find possible scenarios for utilization of such sources, which had been employed insofar for recreational activities in water resorts by means of exploitation of deep wells drilled initially for oil and gas in Paraná Basin. Recent studies were developed several countries aiming at geothermal utilization of sedimentary basins, similar to the Brazilian ones, searching for geothermal resources named Hot Dry Rock (HDR), through injection of fluids that will circulate within rocky fault or fractured crystalline basement and return to the surface in form of vapor in order to be utilized. This scenario is being evaluated and hereto studied for potential utilization in Taubaté Basin. Bibliographic research was made focused in this subject studied and it does not aim to exhaust this subject but rather support such studies and become a starting point. Geophysical logs of 39, mainly water wells drilled in Paraíba do Sul Valley, between Jacareí and Cachoeira Paulista, were analyzed and different lithological beds were interpreted. Temperatures of wells in construction were measured, the thickness of distinguished litologies and a surface trend analysis maps were constructed. The target of this study is the evaluation of the crystalline basement top and its temperature. Throughout this point the study aims to calculate the geothermic grade for the area and evaluate the region potentiality taking into consideration the economic exploitation of the geothermal resources. Two areas in Paraíba Valley have attracted interest and will be subject to new prospections aiming the definition of the Project for Evaluation of Taubaté Basin Geothermal Energy
Mestrado
Geologia e Recursos Naturais
Mestre em Geociências

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Tabibian, Mahmoud. « Natural gas stability and thermal history of the Arbuckle Reservoir, Western Arkoma Basin / ». Access abstract and link to full text, 1993. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9318178.

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Milkie, Jeffrey A. « Condensation of hydrocarbon and zeotropic hydrocarbon/refrigerant mixtures in horizontal tubes ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51825.

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An experimental investigation of condensation of hydrocarbons and hydrocarbon/refrigerant mixtures in horizontal tubes was conducted. Heat transfer coefficients and frictional pressure drops during condensation of a zeotropic binary mixture of R245fa and n-pentane in a 7.75 mm internal diameter round tube were measured across the entire vapor-liquid dome, for mass fluxes ranging from 150 to 600 kg m-2 s-1, and reduced pressures ranging from 0.06 to 0.23. Condensation experiments were conducted for the mixture, as well as its pure constituents over a similar range of conditions. In addition, condensing flow of the hydrocarbon propane was documented visually using high-speed video recordings. Results from these experiments were used to establish the two-phase flow regimes, void fractions, and liquid film thicknesses during condensation of propane flowing through horizontal tubes with internal diameters of 7 and 15 mm. These measurements were made over mass fluxes ranging from 75 to 450 kg m-2 s-1, operating pressures ranging from 952 to 1218 kPa, and vapor qualities ranging from 0.05 to 0.95. Liquid film thickness and void fraction data were subsequently be used to assist the development of heat transfer and pressure drop models. In particular, the heat transfer coefficients and pressure drops observed in the mixture were compared with the corresponding values for the pure constituents. Models for heat transfer and pressure drop in the pure components as well as the mixtures were developed based on the data from the present study. This work extends the available literature on two-phase flow regimes for air-water mixtures, steam, and refrigerants to include hydrocarbons. Additionally, the limited information on condensation in multi-constituent hydrocarbon-hydrocarbon and refrigerant-refrigerant mixtures was extended to include hydrocarbon-refrigerant mixtures. The findings of this study are expected to benefit applications such as refrigeration, low-grade heat-driven power generation, and the development of heat exchangers for the chemical and process industries.

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Lix, Claire. « Present-day fluid-rock interaction in a sedimentary basin : study case of the Granada Basin (Betic Cordillera, Spain) ». Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS200.pdf.

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Comprendre les circulations des fluides dans les bassins sédimentaires joue un rôle crucial dans les divers domaines des ressources naturelles. Dans cette thèse, une approche géochimique est développée pour caractériser la géochimie des eaux souterraines actuelles et pour étudier les réactions affectant un système sédimentaire, en prenant le bassin de Grenade comme cas d'étude. La composition isotopique de l'hélium des gaz libres et dissous a été étudiée afin de contraindre la structure lithosphérique de la région. La composition isotopique de He montre une composante radiogénique dominante avec une contribution mantellique atteignant 1 %. L'évaluation des mécanismes de transport de l'He montre que la croûte est actuellement dissociée du manteau. Nous proposons donc que l’He mantellique observé pourrait résulter d’une contribution fossile du manteau associée à une production crustale à partir de roches riches en Li. Les interactions eau-roche dans les Cordillères Bétiques ont été étudiées en caractérisant les systèmes géothermaux de faible et moyenne enthalpie. Cette étude montre une relation étroite entre la température et la pCO2 dans le réservoir et met en évidence le rôle des tampons minéraux du remplissage sédimentaire et du socle sur la réactivité du CO2. L’étude plus approfondie de la réactivité dans le bassin de Grenade permet de mieux comprendre les écoulements à l’échelle de l’ensemble du bassin. L'évolution de la saturation des eaux vis-à-vis des carbonates, des alumino-silicates et des sulfates permet d'évaluer les chemins possibles d’écoulement dans le bassin et d'appréhender un modèle conceptuel de transport réactif
Understanding fluid circulations in sedimentary basins plays a critical role in the diverse fields of energy and natural resources. In this thesis, a geochemical approach is developed to characterize the present-day groundwater geochemistry and to investigate the reactions affecting a sedimentary system, taking the Granada Basin as a regional study case. Helium isotopic composition of bubbling and dissolved gases has been investigated to set constrains on the lithospheric structure of the area. We found that the He isotopic composition has a dominant radiogenic component with a mantle-derived He contribution reaching mainly 1 %. The evaluation of helium transport mechanisms shows that the crustal system is currently dissociated from the mantle system. We therefore propose that the observed mantle-derived He could result from fossil mantle contribution associated to crustal production from Li-rich rocks. Water-rock interactions in the Central Betic Cordillera have been investigated by characterizing the low- to medium-enthalpy thermal systems. This study, combining geothermometrical methods, shows a strong relationship between the temperature and the pCO2 in the reservoir and highlights the role of the potential mineral buffers of both the sedimentary infilling and the basement on the reactivity of CO2. Further investigations on the reactivity within the Granada Basin allow us to give insights on the groundwater flows at the scale of the whole basin. The evolution of the groundwater saturation with respect to carbonates, alumino-silicates, and sulfates allows to assess the possible flow paths in the basin and to apprehend a conceptual reactive transport model

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Tómasdóttir, Sigrún. « Flow Paths in the Húsmúli Reinjection Zone, Iceland ». Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353580.

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Reinjection of spent geothermal fluids has become common practise in geothermal power plants. Reinjection can, despite being mostly beneficial, have unwanted effects such as cooling of nearby production wells and injection-induced earthquakes. Tracer tests, along with their modeling and interpretation, are important tools for monitoring the flow paths of the injected water and to predict reservoir cooling. Knowledge of flow paths in the system allows for better resource management and a more sustainable utilization. A simulation model of the Húsmúli reinjection zone in the Hellisheiði Geothermal Power Plant in SW-Iceland was developed using the TOUGH2 program. Its hydrological parameters, porosity and permeability, were calibrated using results from an extensive tracer test carried out in the area in 2013-2015. The aim of the simulations was to obtain better understanding of the flow paths in Húsmúli since, despite fast tracer recovery in production wells in the area, hardly any cooling has been observed in those production wells. The results show that the tracer recovery can be modelled by means of permeable flow channels within the medium. Good results for tracer arrival and concentration peaks were obtained both by assuming a single wide channel and several narrower ones. The parameters that gave the best fit for the single channel model were permeability of 5·10-12 m2 and porosity ranging from 0.2%–3%. For the multi-channel model they were 1·10-12 m2 and 0.2%–3.5%, respectively. The high permeability and low porosity in the channels make for an abstract representation of fractured zones within the medium. Greater cooling was seen with the single-channel modelling approach than with the multiple narrower channel approach, the latter showing hardly any cooling in the production elements during the simulation time. This indicates that the flow paths are more likely multiple channels consisting of fracture networks. The simulations show that the flow paths are lengthened by sinking of the fluid to greater depth because of the higher density of the colder injected water. This implies that the injected fluid is warmed up by contact with a larger volume of rock, causing a limited and delayed cooling effect.
Geotermisk energi anses vara en förnybar och miljövänlig energikälla. Som sådan, kan den spela en viktig roll för att minska utsläppen av växthusgaser från energisektorn över hela världen och genom det bekämpa antropogena klimatförändringar. Geotermiska kraftverk extraherar het vätska från berggrunden, separerar ångan från vätskan och använder sedan ångan för att driva turbiner som genererar elektricitet. Injektion av använd geotermisk vätska från kraftverk har blivit vanligt i den geotermiska industrin för att kassera använd geotermisk vätska, upprätthålla systemtrycket och öka produktionseffektiviteten. Återinjektion av nedkyld vätska kan, trots att den är mestadels fördelaktig, ha oönskade effekter, såsom kylning av närliggande produktionsbrunnar och injektionsinducerad seismisk aktivitet. Spårprov, som möjliggör spårning av en kemikalie inom systemet, tillsammans med modellering, är viktiga verktyg för att förstå flödesvägarna för det injicerade vattnet samt att kunna förutsäga nedkylningar av vattenmagasin. Kunskap om flödesvägar i systemet möjliggör bättre resurshantering och ett mer hållbart användande. En simuleringsmodell av återinjektionszonen för det geotermiska kraftverket Hellisheiði på sydvästra Island, Húsmúli, utvecklades med hjälp av simuleringsprogrammet TOUGH2. Dess hydrologiska parametrar, permeabilitet och porositet, kalibrerades med hjälp av resultat från ett omfattande spårtest som utfördes i området 2013-2015. Syftet med simuleringarna var att få en bättre förståelse av flödesvägarna i Húsmúli. Detta er inressant eftersom trots en snabb återhämtning av spårämne i produktionsbrunnar, har knappt någon kylning observerats i området. Resultaten visar att återhämtningen av spårämnet inte kan modelleras med ett homogent medium, men kan istället modelleras genom att bygga permeabla strömningskanaler inom mediet. Goda resultat för spårämnesankomst och koncentrationstoppar erhölls både genom att använda en enda bred kanal och flera smalare. Kanalerna ger en abstrakt representation av sprickzoner inom mediet. Större kylning observerades för modelleringsmetoden med en enkel bred kanal än med flera smalare kanaler. Detta indikerar att flödesvägarna i området troligtvis går genom flera sprickzoner. Flödesvägarna förlängs genom att vätskan sjunker till ett större djup på grund av den högre densiteten hos det injicerade vattnet. Detta innebär att den injicerade vätskan värms upp genom kontakt med en större volym berg, vilket medför en begränsad och fördröjd kylningseffekt.

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Vacek, Tomáš. « Posouzení možnosti připojení kogenerační výrobny 138 MW v Prostějově ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219083.

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The goal of this project is to test the possibility to connect the Cogenerational generation of power 138 MW (still in the development stage) to the control room 110 kV in Prostejov production. This merge would product the electrical energy as well as the heat energy for all local area. In this dissertation we will be considering the solution of the steady state (stationary state) of system with the voltage level of 110kV, as well as the influence of the generation of power on this system, there by the suggesting a connection. The Congenerational production indicates higher effectiveness in the transformation of energy during primary production process due to the production of heat energy as well as the electrical energy from the primary power sources. In our country, as well as around the world, commonly used fuels are fossil fuels- coal, crude oil, and gas. As the demand for energy grows, those supplies are slowly running out. Not to mention that those fuels have a negative environmental impact. They are a source of carbon, which causes damage to the atmosphere and leads to global warming. Power plants which do not produce carbon are much safer for the environment, and much more productive. However, the residue of this energy is challenging to dispose of. Nuclear energy has common attributes with renewing the sources of energies that are extremely friendly to our environment. Nuclear power plants also produce enough energy and with the usage of Fourth generation reactors, they will be able to recycle the nuclear fuels. Today, more importance is put on renewing sources which are more gentle for the environment. In the near future, CEZ Company, the largest producer of electric energy is planning to use water energy. Water energy comes from water plants or dams. Other ecological forms of energy include geothermal and solar energies. These two types of energy are not as applicable for our geographical position. Geothermal energy is commonly used on islands where there is an abundance of natural hot springs. The most discussed source of energy is bioenergy. It uses natural wood sources, recycled wood products, and applies bioenergy as a main source for thermal power plants.

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Liou, Yu-Lun, et 劉昱侖. « Geothermal prototype-Lushan Hot Spring Scenic Area Geothermal Resource Integration Center ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/91156379446688738478.

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碩士
朝陽科技大學
建築及都市設計研究所
98
After Typhoon Sinlaku, disaster occurred in Lushan Hot springs became the tipping on many issues, climate anomalies caused by global warming,elimination of the hillside vegetation, occupation of the riverbed, all became the first level of problem, when government and people begin to aware of the previous action has resulted the finance and even the trouble relate to human lives, The local form of using the land and resource has got to go through a revolution. Under the guidance of the government, dangerous riverbed area has to be abandoned, return the land to the original aspect of the nature itself. They also chose a more secure location to put in the investment. In this new land of hot springs, there are many practices will take place as a response to the previous lands use failures﹒ This context reviews the root of the cause of the problems in the past, for example the way of using the resource causing the climate anomaly, the safety issues came along with the lands being inappropriately developed, environmental issues, the most obvious,immethodicall installed Hot spring facilities damaging the landscape and its looking, etc. Studying and finding the basic strengths of the land itself, for example the abundance of the hot spring resource and other touring vales. While resolving the problems, make the use of the land''s strength the biggest output. Secondly, base on the research data, pinpoint the application of hot spring resource, touring and environment buffering, widely gather all kinds of operating techniques and historical cases, seek for the possibility of any plans, then gather, integrate them. Through the establish of the concept and the resource management plan. Sort out the statistics of the hot spring''s capacity, street''s view, land scape, environmental tour plan (Lushan Hot Spring Scenic Area Geothermal Resource Integration Center ) as a important and influential index of the new area development. Lastly, according to the planned policies and techniques, fulfill them on the design of the entire construction, bring out a brand new constructions and ways on the resource application and the lands development. Also bring out a support plan and space structure for the new hot spring touring. Outline the initial picture of the area''s street view, expecting when developing the hot spring industry can also cover the environmental issues. Avoiding the repeat of yesterday''s mistake.

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Holgate, Fiona Louise. « Exploration and evaluation of the Australian geothermal resource ». Phd thesis, 2005. http://hdl.handle.net/1885/10861.

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A database of 5722 borehole temperatures, AUSTHERM03, has been assembled building upon the existing work of Somerville et al. (1994) through addition of newly available commercial open-file data. The application of more rigorous GIS techniques, including the use of new depth-to-basement and mean annual surface temperature coverages, has resulted in a more reliable extrapolation of this data to 5km depth. A new Australia-wide map of estimated temperature at 5km was created from the extrapolated data by interpolation using geostatistical kriging. The combination of new data and more sophisticated GIS processing has produced a more realistic map image that is characterised in areas of good data density by rounded, well constrained temperature anomalies. In most cases, thermal highs were found to be associated with areas of sedimentary basin cover. Geothermal resource analysis of this image indicates three major regions of prospectivity beneath the Cooper, McArthur and Carnarvon Basins. The use of commercial borehole temperature data in the current AUSTHERM03 temperature map image means that it is affected by temperature suppression caused by the drilling thermal anomaly. Data available in AUSTHERM03 from 330 wells in the Cooper Basin of South Australia provided a unique opportunity to test the reliability of several published models for bottom of hole temperature (BHT) correction. Incorporated into a new database, the Cooper Basin Static Temperature or CBST, 61 of these wells proved suitable for use in thermal modelling. Included within these data were consecutive BHT measurements taken shortly after drilling was completed. Also available were BHT from cement bond logs (CBL) recorded a significant time after drilling which provided a good estimate of true formation temperature and a basis for comparison with model predictions. Four commonly used models of borehole thermal re-equilibration were tested: the Homer plot derived from Bullard (1947), the theoretical dual-media, zero-circulation cylindrical model of Cooper & Jones (1959), the empirical semi-log plot of Pitt (1986) and the exponential model of Nakaya (1953). On average, most models were found to under-estimate the true formation temperature. The magnitude of this bias was dependent upon assumptions implicit in each model. In most cases model prediction accuracy was improved to within around 5% of the CBL when at least one perturbed BHT was recorded >20 hours after the end of drilling. Of the models tested, the theoretical Horner plot was found to have the best combination of accuracy, utility and predictability. Applying this knowledge to perturbed BHT recorded in AUSTHERM03 enabled correction of a subset of 307 Cooper Basin wells using the Horner Plot. Two images of temperature distribution at 5km depth were constructed for these wells, one using the perturbed AUSTHERM03 data, the other the corrected values. While the effects of the drilling temperature suppression were evident on the uncorrected image the overall anomaly structure was found to be largely undisturbed, confirming the utility of the AUSTHERM03 image for geothermal exploration. Located within the Cooper Basin is a strong temperature anomaly that is currently the focus of Australia's first geothermal resource development, Habanera. A geological and geochemical study of drill cuttings derived from Habanero 1, the first deep geothermal well drilled on this site, revealed the presence of a fractured, fractionated 1-type granite body at depth. Similar in composition to many better known granite bodies around Australia, this data provides the basis for a geological model of an Australian-style geothermal resource that compliments the use of temperature mapping as a means of geothermal target generation. Prospective regions identified using this model include the Murray Basin area of NSW Nictoria.

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CINTI, DANIELE. « CARATTERIZZAZIONE GEOCHIMICA DEI FLUIDI E GEOTERMOMETRIA NEL DISTRETTO VULCANICO VICANO-CIMINO. IMPLICAZIONI PER L’UTILIZZO DELLA RISORSA GEOTERMICA ». Doctoral thesis, 2014. http://hdl.handle.net/2158/850905.

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RIASSUNTO Il Distretto Vulcanico Vicano-Cimino (DVVC) è connesso all'attività magmatica post-orogenica che ha interessato il settore peri-tirrenico dell’Italia centrale. La composizione chimica ed isotopica di 333 acque e 25 emissioni gassose indica la presenza di due tipologie di fluidi: 1) acque fredde a chimismo bicarbonatico circolanti a deboli profondità entro formazioni vulcaniche e depositi sedimentari e 2) acque termali a composizione solfato‐bicarbonato‐calcica e ricche in gas (CO2) circolanti entro rocce carbonatiche‐evaporitiche, e separate dagli acquiferi superficiali da formazioni a bassa permeabilità. La fase gassosa, dominata dalla CO2, è comunemente associata alle acque termali emergenti nel DVVC. Essa può, tuttavia, entrare in contatto con gli acquiferi superficiali e, dissolvendo in essi, originare sorgenti a basso pH (acque acetose e bubbling pools) oppure manifestarsi in superficie direttamente dal suolo. L’emergenza di acque termali e gas in superficie si ha preferenzialmente in corrispondenza di elementi fragili (fratture e faglie), i quali forniscono le vie preferenziali per la risalita veloce dei fluidi di origine profonda verso la superficie. Viceversa le acque fredde risultano prive di apporti profondi e non mostrano alcuna relazione con l’assetto strutturale dell’area. Le acque ospitate negli acquiferi superficiali ed in quello profondo sono di origine meteorica e vanno a costituire due tipologie di circolazione: una più superficiale costituita da acque freatiche e di scorrimento, una più profonda dove le acque meteoriche si infiltrano nelle formazioni permeabili in affioramento per fratturazione e vanno ad alimentare il serbatoio idrotermale. Gli isotopi stabili dell’acqua sembrano suggerire una ricarica degli acquiferi di tipo locale, posta approssimativamente a 700‐800 m s.l.m. L'anidride carbonica è prodotta principalmente da reazioni termo-metamorfiche di decarbonatazione entro le porzioni più profonde e più calde dell’acquifero profondo (δ13C-CO2 tra -3.1 e -2.2‰ vs. VPDB) con un contributo minore da degassamento mantellico. I valori relativamente bassi del rapporto R/Ra (0.27-1.19) indicano che l’elio è principalmente derivante da una sorgente crostale con un contributo secondario di risalita dal mantello. Coerentemente, valori relativamente elevati dei rapporti N2/Ar e N2/3He e valori positivi di δ15N-N2 (da 0.91 a 5,7‰ vs AIR) caratterizzano i gas del DVVC, suggerendo la presenza di un significativo “eccesso” di azoto rispetto alla componente atmosferica. Reazioni di riduzione della CO2, in presenza di H2, che avvengono all’interno del serbatoio idrotermale a temperature >200°C, sembrano essere alla base della produzione di metano. I valori di δ34S-H2S (da 9.3 a 11.4‰ vs. VCDT) sono consistenti con l'ipotesi di una origine di H2S da riduzione termochimica delle anidriti Triassiche. Gli equilibri chimici relativi ai sistemi H2O‐H2‐H2S‐Ar e C3H6‐ C3H8 suggeriscono che le specie gassose raggiungono l’equilibrio chimico in un sistema acqua‐dominante a temperature inferiori rispetto a quella massima misurata in pozzo (218°C) ed a condizioni redox controllate dalle interazioni teoriche tra il fluido idrotermale ed un assemblaggio minerale locale. Le temperature relativamente elevate all’interno del serbatoio producono il rilascio di una fase gassosa che si separa dalla fase liquida e che, durante la risalita verso la superficie, è interessata da processi secondari (ri‐equilibrio a bassa temperatura, condensazione di vapore acqueo, dissoluzione entro acquiferi superficiali, attività microbica) che causano perdita di vapore acqueo (per condensazione) e notevoli cambiamenti nelle concentrazioni delle specie sensibili a variazioni della temperatura e delle condizioni redox (H2, CH4, CO2, CO e H2S). Il DVVC può essere considerato favorevolmente in termini di sfruttamento delle risorse geotermiche, sia per usi diretti che per la produzione di energia elettrica tramite sistemi a ciclo binario. In particolare, attraverso l’indagine geochimica si è tentato di fornire gli strumenti necessari per una stima delle potenzialità nei diversi settori dell’area di studio, degli utilizzi più idonei della risorsa e per una attenta valutazione del possibile impatto che i fluidi geotermali possono avere sulle infrastrutture (pozzi, impianti) e sull’ambiente. ABSTRACT The Vicano–Cimino Volcanic District (VCVD) is related to the post-orogenic magmatic activity of the peri- Tyrrhenian sector of Central Italy. The chemical and isotopic compositions of 333 water discharges and 25 gas emissions indicate the occurrence of two main sources: 1) cold Ca-HCO3 to Ca(Na, K)-HCO3 type waters from relatively shallow aquifers hosted in volcanic and sedimentary formations; and 2) thermal Ca-SO4(HCO3) type waters located in a deep CO2-pressurized reservoir, hosted in carbonate–evaporite rocks and separated from the shallow aquifers by thick sequences of low-permeability formations. Carbon dioxide is mainly produced by thermal metamorphic decarbonation within the deepest and hottest parts of the carbonate–evaporite reservoir (δ13C–CO2 from−3.1 to+2.2‰vs. VPDB), likely affected by a mantle-rooted CO2. ReleaseofCO2-rich gases from the deep aquifer into the overlying shallow aquifers produces high-CO2 springs and bubbling pools. The spatial distribution of thermal waters and CO2-rich cold discharges is strongly controlled by fractures and faults located in correspondencewith buried structural highs. Stable isotopes (δD and δ18O) suggest thatmeteoric water feeds both the shallowand deep reservoirs. The relatively lowR/Ra values (0.27–1.19) indicate that He ismainly deriving from a crustal source, with minor component from the mantle affected by crustal contamination related to the subduction of the Adriatic plate. Consistently, relatively high N2/Ar and N2/3He ratios and positive δ15N–N2 values (from0.91 to 5.7‰vs. air) characterize the VCVD gas discharges, suggesting the occurrence of a significant “excess” nitrogen. Isotopic compositions of CH4 (δ13C–CH4 and δD–CH4 values from−28.9 to−22.1‰vs. VPDB and from −176 to −138‰ vs. VSMOW, respectively), and composition of light alkanes are indicative of prevalent thermogenic CH4, although the occurrence of abiogenic CH4 production cannot be excluded. The δ34S–H2S values (from+9.3 to+11.4‰vs. VCDT) are consistentwith the hypothesis of H2S production fromthermogenic reduction of Triassic anhydrites. Gas geothermometry in the H2O–H2–Ar–H2S system suggests that the VCVD gases equilibrated in a liquid phase at redox conditions controlled by interactions of fluids with the local mineral assemblage at temperatures lower (b200 °C) than that andmeasured in deep (N2000 m) geothermalwells. This confirms that secondary processes, i.e. steam condensation, gas dissolution in shallow aquifers, re-equilibration at lower temperature, and microbial activity, significantly affect the chemistry of the uprising fluids. Thermal water chemistry supports the occurrence in this area of an anomalous heat flowthat, coupledwith the recent demographic growth, makes this site suitable for direct and indirect exploitation of the geothermal resource, in agreement with the preliminary surveys carried out in the 1970's–1990's for geothermal exploration purposes.

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Rae, AJ. « Alteration systematics and mineralising potential of the Palinpinon geothermal field, Negros Island, Philippines ». Thesis, 2002. https://eprints.utas.edu.au/21307/1/whole_RaeAndrewJohn2002_thesis.pdf.

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Palinpinon geothermal field (Negros Island, Philippines) is a high temperature, liquid dominated geothermal system in an active volcanic island arc setting. Previous workers have made parallels between the geological setting, mineral deposition and hydrothermal alteration styles recognised at Palinpinon with those that characterise several types of magmatic hydrothermal ore deposits (e.g., porphyry, skarn, and high and low sulphidation epithermal systems). Igneous rock formations on southern Negros Island have medium K, calc-alkaline, basaltic to dacitic compositions. The Middle Miocene Lower Puhagan Volcanic Formation is part of a volcanic sequence that is traceable throughout the Visayas region. It formed during southeasterly-directed subduction of the Sulu Sea oceanic basin beneath the Sulu arc. Late Miocene to Early Pliocene times marked a period of regional subsidence and marine sedimentation during which a thick sequence ( < 1500 m) of calcareous sediments was deposited (Okoy Formation). Locally in the southern Negros region, magmatism during Early Pliocene to Recent times produced a thick (< 2600 m) sequence of volcanic and volcaniclastic rocks (Southern Negros and Cuemos Volcanic Formations). During this time, diorites to quartz diorites of the Puhagan dikes (\(^{40}Ar/^{39} Ar= 4.2-4.1 Ma\)) and the Nasuji Pluton (\(^{40}Ar/^{39} Ar= 0.7-0.3 Ma\)) intruded the Middle Miocene, Late Miocene and Early-Late Phocene rock units. The igneous rocks at Palinpinon have adakitic geochemical signatures and are associated with Nb-enriched basalts. This is interpreted to indicate that magmatism in this region has been influenced by the melting of subducted oceanic basalt. Considering the regional tectonic history, the most likely scenarios for the generation of slab melts are considered to be: (1) melting of relatively young (< 20 Ma) oceanic crust during the Middle Miocene; (2) initiation of east-directed subduction along the Negros-Sulu Trench during Early Pliocene times; and (3) melting of young (< 10-20 Ma) oceanic crust during Late Pliocene times. Hydrothermal alteration at Palinpinon is spatially associated with the Puhagan dikes and the Nasuji Pluton. Only incipient calc-silicate alteration is spatially associated with the Puhagan dikes. In the Nasuji-Sogongon region, the hydrothermal alteration assemblages spatially associated with the Nasuji Pluton are K-silicate (biotite), calc-silicate, hypogene advanced argillic, propylitic and distal ilhte assemblages. Fluid inclusion evidence indicates that magmatic-hydrothermal fluids associated with the final stages of magma crystallisation and the formation of a biotite alteration assemblage and associated veins had homogenisation temperatures of 267° to> 600°C and salinities of 26 to 56 eq.wt.% NaCl. PIXE analyses show that these fluids were endowed with base metals (e.g., up to 0.2 wt.% Cu). Age determinations on hydrothermal biotite (\(^{40}Ar/^{39}Ar= 0.7-0.6 Ma\)), alunite (K/Ar = 0.9-0.8 Ma) and illite (K/Ar = 0.7 Ma) demonstrate that these assemblages all formed contemporaneously with the Nasuji Pluton, implying a genetic link between intrusion emplacement and the formation of porphyry, high sulphidation epithermal and low sulphidation epithermal alteration assemblages. The Early Pliocene age of the Puhagan dikes establishes they are not the heat source to the current geothermal system, which must be a much younger 'blind' intrusion situated beyond depths drilled in the Puhagan area. The emplacement of this intrusion, at depths greater than 2.5 km, occurred within the last 0.8 Ma and provides the heat source for present-day geothermal activity. Distinctive high temperature hypogene hydrothermal alteration types have developed at depths greater than 2 km and include calc-silicate and biotite alteration zones. Parts of the biotite alteration zone are in thermal equilibrium with the present-day geothermal system. The lack of a hypogene advanced argillic alteration zone in the Puhagan region is interpreted to indicate that the intrusion has been emplaced at depths great enough for lithostatic confining pressures to hinder or prevent magma degassing. With ongoing hydrothermal convection, areas of propylitic alteration have developed as halos surrounding the Puhagan magmatic-hydrothermal alteration zones. At shallow crustal levels (< 2 km), low sulphidation (illite) alteration assemblages overprint the biotite and hypo gene advanced argillic alteration types associated with the Nasuji Pluton and are in thermal equilibrium with the present-day geothermal system. Therefore, it is possible that biotite and illite alteration assemblages in the Puhagan region either have a protracted history of formation, or else have formed during two discrete time periods in the past 0.8 Ma. Lastly, perched aquifers of steam-heated acid sulphate water have altered regions above the water table to an advanced argillic (steam-heated) alteration assemblage. The percolation of these waters down near-vertical permeable structures (i.e., faults and joints), results in steeply dipping zones of steam-heated advanced argillic alteration. The current geothermal hydrology at Palinpinon is grossly influenced by permeable zones related to faults and lithological boundaries. The upflow zone is situated at a fault intersection (Ticala and Lagunao Faults) and the main northeasterly outflow zone is parallel to NE-striking faults (Ticala and Puhagan Faults). The neutral chloride reservoir water chemistry is affected by boiling, mixing and conductive cooling. Boiling occurs close to the region of upflow and is mainly restricted to narrow zones of permeability. Mixing occurs peripherally to the upflow zone. The proposed end-member mixing solutions are steam-heated sulphate and meteoric waters. Steam-heated sulphate waters are sourced from perched aquifers in the vadose zone beneath areas of high elevation. Hybrid neutral chloride - sulphate waters have chemistries influenced by host rock dissolution and have not attained chemical equilibrium. In contrast, hybrid neutral chloride - meteoric waters have chemistries that are closer to chemical equilibrium with the host rock. Conductive cooling occurs in the northeasterly outflow zone and water chemistries influenced by this process are also close to chemical equilibrium with the host rock. The occurrence of base and precious metal scale deposits in several geothermal wells demonstrates that the present-day deep reservoir fluid is capable of transporting and depositing base and precious metals. However, trace metal analysis of the deep reservoir fluids shows they are undersaturated with respect to gold (1-4 μg/kg). Chemical modelling of Palinpinon geothermal water predicts that boiling should be the most effective mechanism for base and precious metal deposition. Boiling of the neutral chloride water is predicted to produce sulphide assemblages similar to those seen in well scale deposits. Mixing with acid bearing sulphate waters can also produce these sulphide assemblages, but does so less efficiently, and the deposition of gold and silver is predicted to occur only at much lower temperatures (i.e., < 110°C). In terms of the mineralogy and the sequence of mineral deposition, mixing with meteoric water is predicted to produce the same results as conductive cooling of the neutral chloride water. Based on fluid modelling results, neither can be considered effective deposition mechanisms for base and precious metal mineralisation. Despite indications that both the early magmatic-hydrothermal fluids and the modern hydrothermal fluids were, and are, capable of metal transportation, base and precious metal deposition is not strongly developed at Palinpinon. Geochemical assays of drillcore and drillcuttings show base and precious metal concentrations to be one to two orders of magnitude below ore grade (< 0.02 wt.% Cu, < 0.03 wt.% Pb, < 0.01 wt.% Zn, < 0.01 wt.% Mo, < 8 g/t Ag and <0.05 g/t Au). It may be that the geothermal wells dnlled to date have failed to intersect mmeralised ore zones. Alternatively, the lack of significant ore mineral deposition may imply that there has been, and still is, a lack of sufficient permeability to create a focus for fluid flow. High lithostatic pressures (i.e., > 0.6 kb) during emplacement of the intrusions may account for this apparent lack of permeability in the magmatic-hydrothermal domain. These elevated pressures would also hinder any metal-bearing magmatic brines from ascending to form ore at shallower levels. Therefore, for base and/or precious metal ore deposition to occur at Palinpinon, a resurgence of magmatism may be required, with an influx of metal-bearing brines and gases, and significant fault dilation and/or phreatic/phrcatomagmatic breccia formation to provide favourable permeability for these fluids to escape and form mineralised ore horizons at shallow crustal levels.

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Uddenberg, Matthew Emmanuel. « An assessment of value for deep sedimentary geothermal resources in Texas ». Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5641.

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Building upon work completed by the Bureau of Economic Geology (BEG) for the National Geothermal Data System (NGDS) this thesis develops a coherent strategy for assessing the value of geothermal resources for different regions within Texas. Valuing geothermal resources is difficult because energy output from a specified resource is predicated on the development strategy employed and the dynamic qualities of the reservoir being analyzed. To account for these factors a lumped parameter model is developed to provide a flexible means for assessing the value of different resources. The model is designed to quickly adapt to different reservoir geometries, provided by the NGDS, and account for the dynamic nature of geothermal resources, which will vary as a function of the development strategy employed. In this paper two development strategies for a field located in Hidalgo County have been modeled to illustrate the use of the model and explain how its structure allows for realistic and nuanced analysis. The two scenarios modeled have a sustainable outcome, where the geothermal resource produces a continual low amount of power, and an unsustainable outcome, where power generation is initially high but terminates before the expected life of the project. The outcomes from these two scenarios clearly illustrate the usefulness of using a lumped parameter model to assess the value of a geothermal resource with regards to a set of defined objectives.
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