Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Download Thermal Depletion Of A Geothermal Reservoir With Both Fracture And Por Permeability full books in PDF, epub, and Kindle. Read online Thermal Depletion Of A Geothermal Reservoir With Both Fracture And Por Permeability ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Author : P. W. Kasameyer
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (835 download)
Download or read book Thermal Depletion of a Geothermal Reservoir with Both Fracture and Por Permeability written by P. W. Kasameyer and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Depletion of a Geothermal Reservoir with Both Fracture and Pore Permeability written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A method for estimating the useful lifetime of a reservoir in porous rock where the injection and production wells intersect a fracture system is presented. Equations were derived for the pore-fluid and fracture-fluid temperatures averaged over large regions of the geothermal field. Problems such as incomplete areal sweep and interfingering of cool and hot fluids are ignored. Approximate equations relating average temperatures to the heat flowing from rock to fluid were developed, and their use is justified by comparing the results with solutions of the exact equations. The equations for the temperature decline can be solved quickly. In the model, fractures are characterized by three parameters: aperture w, permeability k/sub fr/, and spacings between fractures D. For certain values of these parameters, cool reinjected fluid in fractures may reach the production wells long before all the warm pore fluid has been tapped, shortening the useful lifetime of the field. The traditional (and important) problems of reservoir engineering, flow rate determination, drawdown, sweep patterns, etc. were ignored. Thus the results are most useful in providing a correction factor which can be applied to lifetime estimates obtained from a detailed simulation of a field assuming porous rock. That correction factor is plotted for clean fractures (k/sub fr/ = w2/12) as a function of w and D for several lifetime ranges. Small-scale fractures seen in cores from the Salton Sea Geothermal Field are too closely spaced to reduce lifetime estimates. However, large-scale fault systems exist within that field, and they are attractive drilling targets because they produce large flow rates. If large scale faults communicate between injection and production wells, they may reduce the useful lifetime of those wells.
Download or read book Application of Thermal Depletion Model to Geothermal Reservoirs with Fracture and Pore Permeability written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The useful lifetime of a geothermal resource is usually calculated by assuming fluid will be produced from and reinjected into a uniform porous medium. However, most geothermal systems are found in fractured rock. If the reinjection and production wells intersect connected fractures, then reinjected fluid may cool the production wells much sooner than would be predicted from calculations of flow in a porous medium. We have developed a "quick and dirty" method for calculating how much sooner that cooling will occur (Kasameyer and Schroeder, 1975, 1976). In this paper, we discuss the basic assumptions of the method, and show how it can be applied to the Salton Geothermal Field, the Raft River System, and to reinjection of supersaturated fluids. 6 refs., 6 figs.
Author : P. W. Kasameyer
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (792 download)
Download or read book Application of Thermal Depletion Model to Geothermal Reservoirs with Fracture and Pore Permeability written by P. W. Kasameyer and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Stefano Benato
Publisher :
ISBN 13 :
Total Pages : 320 pages
Book Rating : 4.:/5 (922 download)
Download or read book Investigation Into Fracture Network Permeability Evolution and Geothermal Reservoir Deformation in Response to Hydraulic Stimulation, Utilizing Coupled Thermo-hydro-mechanical Modeling written by Stefano Benato and published by . This book was released on 2014 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of hydraulic stimulations aimed at enhancing reservoir fracture-permeability were carried out in Desert Peak geothermal well 27-15 from September 2010 to March 2013. Fracture-permeability is controlled by the combined influence of induced thermal (T), hydrologic (H), and mechanical (M) processes, also known as THM. A hydro-mechanical (FLAC3D) model first, and a dual-porosity thermo-hydro-mechanical (TFReact) model second, are implemented to test if the proposed conceptual model is generally able to reproduce observations from the stimulation treatment. Numerical simulations are performed to determine: a) pore pressure diffusion and stress field modifications, b) development of mechanical deformation, and, above all c) relative impact of thermo-mechanical vs. shear deformation on reservoir permeability evolution. Both FLAC3D and TFReact coupled models display an evident cause-effect relation between stimulation of either the shallow or the extended intervals and shear deformation on a deep known structural feature, the STF ("Shearing Target Fault" - where most of the induced microseismicity is observed). Injection-induced thermo-mechanical and hydro-mechanical processes are found to govern permeability enhancement during stimulation of the shallow interval in well 27-15. Conversely, induced shear failure processes developing on a larger structural feature (STF) seem to control most of the permeability gain produced during the well 27-15 extended interval stimulation. Distinctive signatures at the well-head (pressure curve) are shown by the different permeability-change processes, and this is confirmed and matched by coupled THM simulation results.
Download or read book Effects of Water Injection Into Fractured Geothermal Reservoirs written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reinjection of water into fractured geothermal reservoirs holds potential both for improvement and degradation of total energy recovery. The replacement of reservoir fluid can mean support of placement of reservoir pressures and also more efficient thermal energy recovery, but at the same time the premature invasion of reinjected water back into production wells through high permeability fractures can reduce discharge enthalpy and hence deliverability and useful energy output. Increases in reservoir pressure and maintenance of field output have been observed in operating fields, but unfortunately so too have premature thermal breakthroughs. The design of reinjection schemes, therefore, requires careful investigation into the likely effects, using field experimentation. This paper summarizes field experience with reinjection around the world, with the intention of elucidating characteristics of possible problems. The results summarized in this paper fall into three categories of interest: permeability changes dye to injection (both increases and decreases); the path followed by injected water (as indicated by tracer tests); and the thermal and hydraulic influences of injection on the reinjection well itself and on surrounding producers. [DJE-2005].
Author : Geothermal Resources Council
Publisher :
ISBN 13 :
Total Pages : 352 pages
Book Rating : 4.F/5 ( download)
Download or read book Fractures in Geothermal Reservoirs written by Geothermal Resources Council and published by . This book was released on 1982 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Nicolás Rangel Jurado
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (14 download)
Download or read book Thermal Performance Evaluations of Fractured and Closed-loop Geothermal Reservoirs written by Nicolás Rangel Jurado and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earth's interior contains an enormous amount of heat that can be exploited for carbon-free direct-use or electricity generation. Even though numerous studies have predicted that geothermal power will become an important contributor to the world's energy mix, the use of these resources is still growing at a notably slow speed compared to other renewable energy alternatives. This thesis uses computational models to explore the technical challenges that two kinds of geothermal resources face to reach full commercialization. In particular, the temporal evolution of heat production of several fractured and closed-loop geothermal reservoirs is investigated. Thermal-hydraulic simulations are conducted for a fractured meso-scale geothermal reservoir in northern New York, USA. The modeling parameters considered here are constrained by empirical data related to lithology, hydrogeology, and thermal behavior measurements collected on site. This work shows how the addition of realistic complexities, that are well-constrained by field data and often disregarded, can significantly improve the thermal performance predictions compared to overly simplified models. Additionally, the results presented here highlight the importance of characterizing subsurface permeability distributions in order to optimize thermal efficiency and devise appropriate reservoir management strategies that extend the lifespan of geothermal reservoirs. To evaluate how closed-loop or advanced geothermal systems (AGS) compare to alternative ways of extracting geothermal energy, several AGS designs displaying varying reservoir and operating conditions are evaluated to estimate their heat and temperature generating potential. Our findings indicate that the thermal efficiency of AGS is characterized by a considerable exergy loss. Sensitivity analyses show that varying different parameters have slight and moderate improvements on thermal performance, however, AGS designs appear to present multiple technical challenges making them less cost-competitive than both conventional hydrothermal systems and enhanced geothermal systems (EGS). The following key findings summarize the results of these two studies: 1) if well-constrained, computational models are a good tool to assess, manage and intervene geothermal reservoirs to ensure their long-term sustainability, 2) non-uniform permeability can drastically modify fluid flow and heat transport processes in geothermal reservoirs compared to theoretical models that consider homogenous reservoir properties, 3) prospecting adequate subsurface properties is of critical importance to develop geothermal reservoirs, and 4) despite their recent popularity, closed-loop systems are expected to be considerably less productive than other types of geothermal resources at a similar scale.
Download or read book Fracture Propagation and Permeability Change Under Poro-thermoelastic Loads & Silica Reactivity in Enhanced Geothermal Systems written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Therefore, knowledge of the conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fractures are created in the reservoir using hydraulic fracturing. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result, it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have developed advanced poro-thermo-chemo-mechanical fracture models for rock fracture research in support of EGS design. The fracture propagation models are based on a regular displacement discontinuity formulation. The fracture propagation studies include modeling interaction of induced fractures. In addition to the fracture propagation studies, two-dimensional solution algorithms have been developed and used to estimate the impact of pro-thermo-chemical processes on fracture permeability and reservoir pressure. Fracture permeability variation is studied using a coupled thermo-chemical model with quartz reaction kinetics. The model is applied to study quartz precipitation/dissolution, as well as the variation in fracture aperture and pressure. Also, a three-dimensional model of injection/extraction has been developed to consider the impact poro- and thermoelastic stresses on fracture slip and injection pressure. These investigations shed light on the processes involved in the observed phenomenon of injection pressure variation (e.g., in Coso), and allow the assessment of the potential of thermal and chemical stimulation strategies.
Author : Society of Petroleum Engineers of AIME.
Publisher :
ISBN 13 :
Total Pages : 1016 pages
Book Rating : 4.:/5 (31 download)
Download or read book Society of Petroleum Engineers Journal written by Society of Petroleum Engineers of AIME. and published by . This book was released on 1985 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : R. Lee Aamodt
Publisher :
ISBN 13 :
Total Pages : 70 pages
Book Rating : 4.:/5 (319 download)
Download or read book The Induction and Growth of Fractures in Hot Rock written by R. Lee Aamodt and published by . This book was released on 1972 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parametric Analysis of Factors Affecting Injection and Production in Geothermal Reservoirs written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A program was designed to allow the study of the effects of several parameters on the injection of water into and production of fluid from a fractured low porosity geothermal reservoir with properties similar to those at The Geysers. Fractures were modeled explicitly with low porosity, high permeability blocks rather than with a dual-porosity formulation to gain insight into the effects of single fractures. A portion of a geothermal reservoir with physical characteristics similar to those at the Geysers geothermal field was constructed by simulating a single fracture bounded by porous matrix. A series of simulation runs were made.using this system as a basis. Reservoir superheat prior to injection, injection temperature, angle of fracture inclination, fracture/matrix permeability contrast, fracture and matrix relative permeability, and the capillary pressure curves in both fracture and matrix were varied and the effects on production were compared. Analysis of the effects of these parameter variations led to qualitative conclusions about injection and production characteristics at the Geysers. The degree of superheat prior to water injection was found to significantly affect the production from geothermal reservoirs. A high degree of superheat prior to injection increases the enthalpy of the produced fluid and causes the cumulative produced energy to nearly equal that from a reservoir which began injection much earlier. Injection temperature was found to have very little effect on production characteristics. Angle of fracture inclination affects the enthalpy of the produced fluid. Fractures dipping toward the production well allow greater flow of water toward the producer resulting in lower enthalpies of produced fluid. The fracture/matrix permeability contrast was shown to influence the production in an expected way: The lower the contrast, the lower the production rate, and the lower the enthalpy of the produced fluid at a given time. Results obtained by varying relative permeability show that the relative permeability curves used have little effect on the production from the reservoir. This indicates that the transfer between the matrix and the fracture is dominated by capillary forces, thus reducing the importance of the shape of the relative permeability curve. Capillary pressure curves were shown to have a strong effect on production characteristics, further emphasizing the importance of capillary forces in Geysers-type geothermal reservoirs.
Author :
Publisher :
ISBN 13 :
Total Pages : 12 pages
Book Rating : 4.:/5 (684 download)
Download or read book Tectonic Controls on Fracture Permeability in a Geothermal Reservoir at Dixie Valley, Nevada written by and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: To help determine the nature and origins of permeability variations within a fault-hosted geothermal reservoir at Dixie Valley, Nevada, the authors conducted borehole televiewer logging and hydraulic fracturing stress measurements in six wells drilled into the Stillwater fault zone at depths of 2--3 km. Televiewer logs from wells penetrating the highly permeable portion of the fault zone revealed extensive drilling-induced tensile fractures. As the Stillwater fault at this location dips S45°E at (approximately) 53° it is nearly at the optimal orientation for normal faulting in the current stress field. Hydraulic fracturing tests from these permeable wells show that the magnitude of S{sub hmin} is very low relative to the vertical stress S{sub v}. Similar measurements conducted in two wells penetrating a relatively impermeable segment of the Stillwater fault zone 8 and 20 km southwest of the producing geothermal reservoir indicate that the orientation of S{sub hmin} is S20°E and S41°E, respectively, with S{sub hmin}/S{sub v} ranging from 0.55--0.64 at depths of 1.9--2.2 km. This stress orientation is near optimal for normal faulting on the Stillwater fault in the northernmost non-producing well, but (approximately) 40° rotated from the optimal orientation for normal faulting in the southernmost well. The observation that borehole breakouts were present in these nonproducing wells, but absent in wells drilled into the permeable main reservoir, indicates a significant increase in the magnitude of maximum horizontal principal stress, S{sub Hmax}, in going from the producing to non-producing segments of the fault. The increase in S{sub Hmaz}, coupled with elevated S{sub hmin}/S{sub v} values and a misorientation of the Stillwater fault zone with respect to the principal stress directions, leads to a decrease in the proximity of the fault zone to Coulomb failure. This suggests that a necessary condition for high reservoir permeability is that the Stillwater fault zone be critically stressed for frictional failure in the current stress field.
Author : Murad AbuAisha
Publisher :
ISBN 13 : 9783330872134
Total Pages : pages
Book Rating : 4.8/5 (721 download)
Download or read book Geothermal Reservoir Stimulation Using The Finite Element Method written by Murad AbuAisha and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical Model Studies of Explosion-Fractured Geothermal Reservoirs written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large scale utilization of geothermal energy will require means for enhanced energy extraction from geothermal reservoirs since the higher quality hydrothermal resources adequate for commercial electricity generation represent only a small fraction of the estimated resource base. Technologies are being developed for artificial fracturing of hydrothermal and dry hot rock geothermal resources to obtain adequate permeability for water circulation and to expose new rock surface area. Non-isothermal processes such as in-place boiling or artificial circulation of cooler fluids can be used to extract the energy from the fractured formation. To evaluate non-isothermal heat transfer processes, physical model studies were conducted in the Stanford Geothermal Program fractured-rock reservoir model capable of operating at a maximum pressure of 800 psig at 500oF. The 17-ft3 physical model has been described previously [Hunsbedt, Kruger, and London (1975), Hunsbedt (1975), and Hunsbedt, Kruger and London (1976)]. A summary of the characteristics of the relatively large fracture-permeability rock systems tested in the model are summarized in Table 1. The porosity and permeability characteristics of these systems resembled those of fracture-stimulated ones created by high-energy explosives. 1 tab., 4 refs., 2 figs.
Author : Lawrence Berkeley Laboratory
Publisher :
ISBN 13 :
Total Pages : 8 pages
Book Rating : 4.:/5 (81 download)
Download or read book Enthalpy Transients in Fractured Two-phase Geothermal Systems written by Lawrence Berkeley Laboratory and published by . This book was released on 1985 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (727 download)
Download or read book Effects of Capillarity and Vapor Adsorption in the Depletion of Vapor-dominated Geothermal Reservoirs written by and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vapor-dominated geothermal reservoirs in natural (undisturbed) conditions contain water as both vapor and liquid phases. The most compelling evidence for the presence of distributed liquid water is the observation that vapor pressures in these systems are close to saturated vapor pressure for measured reservoir temperatures (White et al., 1971; Truesdell and White, 1973). Analysis of natural heat flow conditions provides additional, indirect evidence for the ubiquitous presence of liquid. From an analysis of the heat pipe process (vapor-liquid counterflow) Preuss (1985) inferred that effective vertical permeability to liquid phase in vapor-dominated reservoirs is approximately 1017 m2, for a heat flux of 1 W/m2. This value appears to be at the high end of matrix permeabilities of unfractured rocks at The Geysers, suggesting that at least the smaller fractures contribute to liquid permeability. For liquid to be mobile in fractures, the rock matrix must be essentially completely liquid-saturated, because otherwise liquid phase would be sucked from the fractures into the matrix by capillary force. Large water saturation in the matrix, well above the irreducible saturation of perhaps 30%, has been shown to be compatible with production of superheated steam (Pruess and Narasimhan, 1982). In response to fluid production the liquid phase will boil, with heat of vaporization supplied by the reservoir rocks. As reservoir temperatures decline reservoir pressures will decline also. For depletion of ''bulk'' liquid, the pressure would decline along the saturated vapor pressure curve, while for liquid held by capillary and adsorptive forces inside porous media, an additional decline will arise from ''vapor pressure lowering''. Capillary pressure and vapor adsorption effects, and associated vapor pressure lowering phenomena, have received considerable attention in the geothermal literature, and also in studies related to geologic disposal of heat generating nuclear wastes, and in the drying of porous materials. Geothermally oriented studies were presented by Chicoine et al. (1977), Hsieh and Ramey (1978, 1981), Herkelrath et al. (1983), and Nghiem and Ramey (1991). Nuclear waste-related work includes papers by Herkelrath and O'Neal (1985), Pollock (1986), Eaton and Bixler (1987), Pruess et al. (1990), Nitao (1990), and Doughty and E'ruess (1991). Applications to industrial drying of porous materials have been discussed by Hamiathy (1969) arid Whitaker (1977). This paper is primarily concerned with evaluating the impact of vapor pressure lowering (VPL) effects on the depletion behavior of vapor-dominated reservoirs. We have examined experimental data on vapor adsorption and capillary pressures in an effort to identify constitutive relationships that would be applicable to the tight matrix rocks of vapor-dominated systems. Numerical simulations have been performed to evaluate the impact of these effects on the depletion of vapor-dominated reservoirs.
