ISSN:0363-907X    

DOI:10.1002/er.4440090303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper provides an overview of the present status of geothermal energy world‐wide. Although the origin of this form of energy dates back in history, its impetus (with the notable exceptions of Italy and Iceland) was the ‘energy crisis’ of the mid to late 1970s.A wide range of speculations were made during those years as to the potential contribution of geothermal energy to the world energy demand. The present lull in the energy scene allows a more realistic assessment of present and near future potential.Problem areas related to the development of the geothermal resource potential are also discussed. They address both natural, mainly liquid dominated, sources and the recovery of heat stored at depth in impervious rocks through man‐made geothermal reservoirs known as the hot dry rock concept of heat

ISSN:0363-907X    

DOI:10.1002/er.4440090304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper examines in a very broad fashion the formation of geothermal resources at lithospheric subduction zones. Regions of highly silicic calc‐alkaline Quaternary volcanoes and/or plutons have been identified as prime candidates for having high‐temperature hydrothermal systems. Regions of large tholeiitic Quaternary volcanoes have been identified as prime candidates for having large moderate‐temperature hydrothermal systems. In addition, active magmatic, phreatomagnetic, and/or tectonic fracturing must be occurring in order to keep any moderate to high temperature hydrothermal system from chemically sealing. Connate, meteoric and/or oceanic water sources must also be present.Owing to tectonic and magmatic processes, volcanic arcs of subduction zones represent regions of the crust that have anomalously high mechanical and heat energy. Such arc regions are expected to contain significantly more moderate to high temperature hydrothermal systems than what is presently known. Many of these arcs are briefly discussed with respect to their potential for containing such reso

ISSN:0363-907X    

DOI:10.1002/er.4440090305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractGeophysical prospecting of high temperature geothermal reservoirs aims at identifying either fluid trapping structures or anomalies related to the properties of the hydrothermal fluid and rock to fluid interactions. Two types of reservoir environments can be characterized: (i) sedimentary reservoirs when a carbonate reservoir is generally capped by a dominantly argillaceous, hydraulically impervious and thermally insulating cover, and (ii) volcanic and volcano‐sedimentary reservoirs associated with hydrothermally altered areas.Based on the aforementioned exploration goals and reservoir settings, a wide spectrum of geophysical methods can be applied whose selection is largely commanded by local geological conditions and expected reservoir morphology.Major geophysical techniques are reviewed and their potential, as to geothermal reservoir prospecting issues, discusse

ISSN:0363-907X    

DOI:10.1002/er.4440090306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTechniques based on the variations in composition of water, gas and stable isotopes in the liquid and gas phases of the geothermal fluids have been applied for some time now in the major geothermal fields and are now also used regularly in geothermal exploration.There are numerous processes capable of modifying isotopic composition after infiltration of water from the surface, such as water‐rock exchanges, formation of secondary minerals and exchange with the gaseous phase (CO2and H2S). During ascent to the surface, the two main processes are steam separation and dilution and mixing with shallower waters.This paper also deals with the chemical characteristics of the waters, their classification and the water‐rock interaction producing hydrothermal alteration.During exploration the chemical and isotopic geothermometers represent a unique method for investigating the deep system. The choice of geothermometer and interpretation of geothermometric data are two crucial steps in geothermal exploration.Finally, the paper discusses the geochemistry of gas mixtures, especially the origin of the gas species and the main chemical reactions that produce semi‐empirical geothermometers and some recent non‐empirical geothermometers based on models of a two‐phase system in the reservoir. Gas‐geothermometers can be developed to calculate the reservoir temperature for natural man

ISSN:0363-907X    

DOI:10.1002/er.4440090307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractReservoir engineering evaluation of geothermal systems attempts to provide answers on the extent of the reserves, their probable longevity and the deliverability and production rate of the reservoir. Economic decisions on the desirability of the exploitation of the particular reservoir hinge on these findings.This paper presents a set of calculational procedure and thinking sequences available to the geothermal reservoir engineer that would aid in an appropriate management decision.An exploitable geothermal system consists of a fluid as well as a heat reservoir. Since much of the heat is stored in the confining rock, reinjection strategies are outlines for the efficient mining of heat.

ISSN:0363-907X    

DOI:10.1002/er.4440090308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper is intended to be a state of the art review of geothermal reservoir simulation. Its recent application to the modelling of real geothermal reservoirs is described and put in the context of an emerging general approach to reservoir modelling. The use of computer simulation for geothermal well test analysis is described. One of the main recent uses of reservoir simulators has been for conducting numerical experiments aimed at improving the understanding of geothermal reservoir physics. Such studies on fractured reservoirs, the thermal structure of reservoirs and the effects of non‐condensable gases and dissolved salts are outline

ISSN:0363-907X    

DOI:10.1002/er.4440090309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractChemical thermodynamics of geothermal brines are important in every aspect of geothermal development, starting from initial stages of exploration to the final stages of utilization. Yet there are serious gaps in the knowledge of high temperature thermodynamics of aqueous fluids. The critical areas of chemical thermodynamics that need serious evaluation include: (1) chemical and physical characteristics of aqueous solutions at high temperatures, (2) solubility and phase behaviour of numerous inorganic solids in aqueous media at high temperatures, (3) solubility and flash behaviour of gases in equilibrium with aqueous media at high temperatures and (4) cement, metal and other material resistivity to any mechanical and/or chemical degradation in various high temperature aqueous environments. The present paper reviews the status of the various aspects of chemical thermodynamics. The emphasis is placed in reviewing the various methodologies used in predicting scale formation and gas flashing during the production of geothermal brines. Various well‐known models used in obtaining the chemical thermodynamic information are also critically reviewed. The general lack of knowledge on the data bases related to solubility of various species in high temperature brine is clearly pointed out. Based on the critical review of chemical thermodynamics of geothermal brines, the following conclusions are made:1. The basic chemical thermodynamics of aqueous systems at high temperatures are not well known.2. There is a lack of a thorough and reliable data base related to the phase behaviour of inorganic solids and their solubilities in aqueous media at high temperatures.3. The solubilities and flash behaviours of gases in equilibrium with aqueous media at high temperatures and high pressures are not well know

ISSN:0363-907X    

DOI:10.1002/er.4440090310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractPotential resources and applications of earth heat in the form of geothermal energy are large. World‐wide direct uses amount to 7072 MW thermal above a reference temperature of 35°C. District heating is the major direct use of geothermal energy. Equipment employed in direct use projects is of standard manufacture and includes downhole and circulation pumps, transmission and distribution pipelines, heat exchangers and convectors, heat pumps and chillers. Direct uses of earth heat discussed are district heating and cooling, greenhouse heating and fish farming, process and industrial applications, combined and cascading uses. The economic feasibility of direct use projects is governed by site specific factors such as location of user and resource, resource quality, system load factor and load density, as well as financing. Examples are presented of district heating in Reykjavík, Klamath Falls, Melun l'Amont and Svartsengi. Further developments of direct uses of geothermal energy will depend on matching user needs to the resource, and improving load factors and load dens

ISSN:0363-907X    

DOI:10.1002/er.4440090311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe term hot dry rock (HDR) has been used to describe the exploitation of the thermal energy contained in rocks that have a sufficiently high temperature but contain insufficient fluids to enable the heat to be extracted. The attraction of such a resource is that it is probably available everywhere, but at varying depths.International activity has focused on the problem of circulating fluids through the rock and extracting the heat by conduction from the rock to the fluid. The initial concepts were based on creating individual cracks to interlink two wells approximately 500 m apart. The necessary heat exchange area was to be achieved by using multiple systems of interconnections in parallel. The results from the field work have shown that the interlinking is dominated by stimulated natural joints and the degree of normal dilation that can be achieved is limited by the orientation of the natural discontinuity with the pre‐existing stresses and, hence, the shear stress on the joint. The normal dilation is important because it controls the resistance to flow between the wells. The shear mechanism controls the far‐field water losses and the direction of growth of the more permeable interwell region and has obvious implications for the proposed geometry of any system.The cost of drilling has been shown to be comparable to deep drilling for other purposes and the development of deviated holes in strong crystalline rocks has been shown to be possible.The progress of the stimulation has been mapped successfully by locating the microseismic events generated by shearing but the relationship of the microseismically active areas and the heat transfer region has yet to be identified.No adverse environmental problems have been identified; the produced fluids are generally benign and the microseismicity is well below any threshold of damage.The goal of a universally available heat source free of stack emissions and waste products that does not consume finite reserves of minerals and hydrocarbon demands substantial investment in the research to determine if it is attainable. The major field programmes should have reached their preliminary conclusions by the middle of 1

ISSN:0363-907X    

DOI:10.1002/er.4440090312

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY