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Linear Water Influx of an Infinite Aquifer Through a Partially Communicating Fault

Description: This paper presents a linear flow water influx analysis method where the aquifer is separated from the reservoir by a partially communicating fault. Transient pressure distributions are considered both in the reservoir and in the aquifer. Cases where the leaky fault is located within the aquifer can be analyzed with this model given a superposition of constant rate flow periods at the oil-water interface. Constant production rate is specified at the inner boundary, without inner boundary storag… more
Date: January 20, 1987
Creator: Ambastha, Anil K. & Sageev, Abraham
Partner: UNT Libraries Government Documents Department
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Tracer Flow in a Fractured Geothermal Reservoir Model

Description: Tracer injection for identifying reservoir and transport parameters in geothermal sources has become an important procedure for designing an optimum reinjection program. Field tests have been analyzed using convection-diffusion equation to predict fracture size, width and probable thermal breakthrough times. The present study was conducted in a laboratory fractured reservoir model whose physical properties were known. The tracer, KI, breakthrough profiles were analyzed for different injection-p… more
Date: January 20, 1987
Creator: Bayar, M. & Okandan, E.
Partner: UNT Libraries Government Documents Department
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Analysis of Thermally Induced Permeability Enhancement in Geothermal Injection Wells

Description: Reinjection of spent geothermal brine is a common means of disposing of geothermal effluents and maintaining reservoir pressures. Contrary to the predictions of two-fluid models (two-viscosity) of nonisothermal injection, an increase of injectivity, with continued injection, is often observed. Injectivity enhancement and thermally-affected pressure transients are particularly apparent in short-term injection tests at the Los Azufres Geothermal Field, Mexico. During an injection test, it is not … more
Date: January 20, 1987
Creator: Benson, S. M.; Daggett, J. S.; Iglesias, E.; Arellano, V. & Ortiz-Ramirez, J.
Partner: UNT Libraries Government Documents Department
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Geothermal Energy - An Emerging Resource

Description: Address on the Department of Energy's overall energy policy, the role of alternative energy sources within the policy framework, and expectations for geothermal energy. Commendation of the industry's decision to pursue the longer-term field effort while demand for geothermal energy is low, and thus prepare for a substantial geothermal contribution to the nation's energy security.
Date: January 20, 1987
Creator: Berg, John R.
Partner: UNT Libraries Government Documents Department
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Interference Tests at Kawerau, New Zealand

Description: Analysis of interference tests at the Kawerau geothermal field in New Zealand has indicated that the reservoir may be viewed on a coarse scale as a two-layer structure. While these layers have high permeabilities, they are in poor hydrological communication with each other. The shallower layer is modelled as a finite cylindrical reservoir. The deeper layer is modelled as a larger cylindrical reservoir with recharge from the sides. The fitted permeabilities and storativities suggest the importan… more
Date: January 20, 1987
Creator: Burnell, John G. & McGuinness, Mark J.
Partner: UNT Libraries Government Documents Department
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Geothermal Well Stimulated Using High Energy Gas Fracturing

Description: This paper reports the result of an experimental study of the High Energy Gas Fracturing (HEGF) technique for geothermal well stimulation. These experiments demonstrated that multiple fractures could be created to link a water-filled borehole with other fractures. The resulting fracture network and fracture interconnections were characterized by flow tests as well as mine back. Commercial oil field fracturing tools were used successfully in these experiments. 5 refs., 2 tabs., 5 figs.
Date: January 20, 1987
Creator: Chu, T.Y.; Jacobson, R.D.; Warpinski, N. & Mohaupt, Henry
Partner: UNT Libraries Government Documents Department
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Acceleration of polarized protons in AHF (Advanced Hadron Facility)

Description: In this paper an analysis of the depolarization expected during acceleration from 0.8 to 45.0 GeV kinetic energy in the Advanced Hadron Facility (AHF) accelerators is performed.
Date: March 20, 1987
Creator: Colton, E. P.
Partner: UNT Libraries Government Documents Department
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Gas Geochemistry of the Dogger Geothermal Aquifer (Paris Basin, France)

Description: The low enthalpy program developed in the Paris Basin provides the opportunity for studying the gas geochemistry of the calcareous aquifer of the Dogger. Hydrocarbons and CO{sub 2} are mainly biogenic, He displays high concentrations. He, Ar and N{sub 2} have multiple origins (radioactive decay, atmospheric migration, biochemical processes). The distribution of the gases in the zones of the basin varies in relation to the general chemistry, sedimentology and hydrodynamics. The gas geothermomete… more
Date: January 20, 1987
Creator: Criaud, A.; Fouillac, C.; Marty, B.; Brach, M. & Wei, H. F.
Partner: UNT Libraries Government Documents Department
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Neutron Production of Charm Particles in Fermilab E-400

Description: Results are presented from Fermilab E-400 on the production of charmed baryons and mesons using incident neutrons. We show evidence for the charm-strange baryon, ..xi../sub c//sup +/, and present our measurements of its mass, width, lifetime, cross section and relative branching fractions, and the A, x/sub f/, p/sub t/, and particle/antiparticle dependence of the state. We show evidence for both the ..sigma../sub c//sup + +/ and ..sigma../sub c//sup 0/, and present measurements of three mass di… more
Date: August 20, 1987
Creator: Cumalat, J. P.; Binkley, M.; Bossi, F.; Butler, J.; Coteus, P.; DiCorato, M. et al.
Partner: UNT Libraries Government Documents Department
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Gas Geothermometry Based on CO Content--Application in Italian Geothermal Fields

Description: This paper discusses gas chemical equilibria in geothermal reservoirs involving the species CO{sub 2}, CH{sub 4}, CO, H{sub 2}S, H{sub 2}, and H{sub 2}O. A set of equations is developed correlating ratios of gas to CO{sub 2} with temperature, steam fraction, and CO{sub 2} partial pressure in the reservoir. A method for solving the set of nonlinear equations is proposed. These equations do not involve discharge gas/total H{sub 2}O ratios and may therefore be used for fumaroles and hot-spring flu… more
Date: January 20, 1987
Creator: D'Amore, F.; Fancelli, R.; Saracco, L. & Truesdell, A.H.
Partner: UNT Libraries Government Documents Department
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Magma Energy Extraction

Description: The rate at which energy can be extracted from crustal magma bodies has an important influence on the economic viability of the magma energy concept. Open heat exchanger systems where fluid is circulated through solidified magma offer the promise of high energy extraction rates. This concept was successfully demonstrated during experiments in the molten zone of Kilauea Iki lava lake. Ongoing research is directed at developing a fundamental understanding of the establishment and long term operat… more
Date: January 20, 1987
Creator: Dunn, J. C.; Ortega, A.; Hickox, C. E.; Chu, T. Y.; Wemple, R. P. & Boehm, R. F.
Partner: UNT Libraries Government Documents Department
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Applying Flowrate Type Curves to Geysers Steam Wells

Description: Dimensionless flowrate type curves were applied to steam wells at The Geysers in an attempt to quantify reservoir properties and to predict flowrate decline. Although data scatter was a problem, the flowrate data was smoothed by a normalization routine based on the back-pressure equation and the wells were modeled by dimensionless functions for a radial system with a infinite or finite outer boundary and a constant pressure inner boundary (composite analytical-empirical type curve). The “match”… more
Date: January 20, 1987
Creator: Enedy, Steve
Partner: UNT Libraries Government Documents Department
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Fracture Detection in Geothermal Wells Drilled in Volcanic Rocks

Description: The Phlegrean Fields, close to Naples, are the site of important geothermal activity. The formations are volcanic and mostly tuffites. They are originally very tight but the geothermal alteration locally produces fractures with large increase in permeability. The lack of geological markers makes well-to-well correlation quite difficult. Thus the local detection of fractured zones in each well is very important for the evaluation of its potential. The Mofete 8 D well is a typical example. A rath… more
Date: January 20, 1987
Creator: Gonfalini, Mauro; Chelini, Walter; Cheruvier, Etienne; Suau, Jean & Klopf, Werner
Partner: UNT Libraries Government Documents Department
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An atmospheric correction algorithm for remote identification of non-Lambertian surfaces and its range of validity

Description: The usefulness of remotely sensed surface data depends on the ability to correct for atmospheric pertubations on the image. An atmospheric correction algorithm has been proposed which removes atmospheric pertubations from off-nadir measured radiances at the top of the atmosphere in the visible and near-infrared wavelength region. The ability of the model to reproduce radiance distributions at the surface from radiances at the top of the atmosphere is tested and found to be better than 15%. The … more
Date: February 20, 1987
Creator: Gratzki, A. & Gerstl, S.A.W.
Partner: UNT Libraries Government Documents Department
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Active Seismics to Determine Reservoir Characteristics of a Hot Dry Rock Geothermal System

Description: Since 1981 three wells have been drilled to depths of between 2.0 and 2.6 km in the Carnmenellis granite, Cornwall, England in order to create a HDR geothermal system. These wells are separated by between 150 and 300 m and have been hydraulically connected by massive injections of both water and viscous gel (50 cpoise). Passive microseismic monitoring of the hydraulic stimulation and circulation experiments has been used since 1982 to determine the size and structure of the reservoir, and monit… more
Date: January 20, 1987
Creator: Green, A.S.P. & Baria, R.
Partner: UNT Libraries Government Documents Department
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Analysis of Transient Pressure Tests for Olkaria Exploration Wells

Description: Analysis of transient pressure tests for Olkaria West wells shows that both infinite acting and double porosity models can be used to analyze the well behaviour and infer reservoir properties from fall-off steps of long enough duration, in wells where no significant thermal recovery occurs. The double porosity model gives better estimates of reservoir properties than the infinite acting model, for long fall-off steps in wells intercepting fractures. Semilog methods give fairly good estimates of… more
Date: January 20, 1987
Creator: Haukwa, Charles B.
Partner: UNT Libraries Government Documents Department
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Perturbations of the sun's gravitational field due to solar oscillations

Description: Considerable evidence has been presented for the detection of low-degree internal gravity modes of the Sun. By combining the observations obtained at the Crimean Astrophysical Observatory and at SCLERA, a number of the modes have been classified with respect to their spatial properties. The number of such modes classified has been extended in a subsequent gravity-mode classification project by Gu and Hill. These mode classifications have been tested using three additional sets of independent ob… more
Date: October 20, 1987
Creator: Hill, H.A.
Partner: UNT Libraries Government Documents Department
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Development Drilling, Testing and Initial Production of the Beowawe Geothermal Field

Description: The Beowawe geothermal field in north central Nevada is generating 16MW using two production wells (Ginn 1-13 and 2-13) and one injection well (Batz). Drilling the second production well (Chevron Ginn 2-13) in 1985 led to the discovery of a second productive strand of the Malpais fault zone. The wells are completed in the Malpais fault zone and are capable of producing 420+°F geothermal fluid at rates exceeding 1,000,000 lbs/hr. Initial testing suggests that the completion zones of the two prod… more
Date: January 20, 1987
Creator: Hoang, V.T.; James, E.D. & Epperson, I.J.
Partner: UNT Libraries Government Documents Department
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Sensitivity Analysis of Dual-Permeability Systems

Description: The substitution of matrix permeability for fracture permeability to simplify the simulation of complex fracture systems requires a radically different treatment of transport in the matrix. The spatial distribution of pressure is reasonably well described by inclusion of only the major fractures. Transport of tracer and heat, however, depends on a detailed knowledge of fluid velocities. These velocities are dependent on the active porosity of the system. Because fractures channel flow, the acti… more
Date: January 20, 1987
Creator: Hull, Laurence C. & Clemo, Tom M.
Partner: UNT Libraries Government Documents Department
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Petrophysical Properties of Twenty Drill Cores from the Los Azufres, Mexico, Geothermal Field

Description: For this study we selected 20 drill cores covering a wide range of depths (400-3000 m), from 15 wells, that provide a reasonable coverage of the field. Only andesite, the largely predominant rock type in the field, was included in this sample. We measured bulk density, grain (solids) density, effective porosity and (matrix) permeability on a considerable number of specimens taken from the cores; and inferred the corresponding total porosity and fraction of interconnected total porosity. We char… more
Date: January 20, 1987
Creator: Iglesias, E. R.; Contreras L., E.; Garcia G., A. & Dominquez, Bernardo A.
Partner: UNT Libraries Government Documents Department
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Vapor-Dominated Zones within Hydrothermal Convection Systems

Description: Three conceptual models are presented to illustrate the range of natural hydrothermal convection systems in which vapor-dominated conditions are found. Numerical simulation is used to test the feasibility of these models and to demonstrate geologically plausible evolutionary pathways for each model. 2 figs., 13 refs.
Date: January 20, 1987
Creator: Ingebritsen, S.E.
Partner: UNT Libraries Government Documents Department
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The Electrokinetic Mechanism of Hydrothermal-Circulation-Related and Production-Induced Self-Potentials

Description: Self-potential (SP) surveys were carried out on a number of geothermal areas in Japan during the last decade. In most cases SP anomalies of positive polarity are found to overlie high temperature upflow zones. Streaming potential generated by hydrothermal circulation (Ishido, 1981) is considered to be the most likely cause of the observed positive anomalies. Repeated surveys conducted on the Nigorikawa caldera in Japan detected a change in SP induced by production of geothermal fluids. The obse… more
Date: January 20, 1987
Creator: Ishido, T.; Kikuchi, T. & Sugihara, M.
Partner: UNT Libraries Government Documents Department
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Structure, Permeability and Production Characteristics of the Heber, California Geothermal Field

Description: The three key permeability elements of the Heber reservoir are “capping” clays above 1800', a sedimentary “matrix permeability” reservoir from 1800'-5500', and fracture permeability in indurated sediments below 5500'. The fractures are related to NW trending strike-slip faults and NE trending normal faults. Maps and cross sections with dipmeter, lost circulation, temperature and Kh data illustrate the structures and their control on the movement of thermal waters. Production creates a strong in… more
Date: January 20, 1987
Creator: James, E.D.; Hoang, V.T. & Epperson, I.J.
Partner: UNT Libraries Government Documents Department
open access

Discharging Through an Orifice Determines Steam-Water Enthalpy

Description: Abstract: A wide range of steam-water mixtures was discharged to the atmosphere through a 10.7 mm diameter orifice which was sharp-edged with a minuscule throat pressure tapping. The ratio of throat pressure to up-stream pressure was found sensitive to dryness fraction over the whole range studied from 0.03 to 1.0. The technique (employing large orifices) has the potential of identifying the unknown enthalpy of geothermal wells discharging large flows. Contrariwise, a nozzle (rounded entry orif… more
Date: January 20, 1987
Creator: James, Russell
Partner: UNT Libraries Government Documents Department
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