Download or read book Fracturing and Sealing in Geothermal Systems written by Michael Lee Batzle and published by . This book was released on 1978 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydraulic fracturing and geothermal energy written by S. Nemat-Nassar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing has been and continues to be a major techno logical tool in oil and gas recovery, nuclear and other waste disposal, mining and particularly in-situ coal gasification, and, more recently, in geothermal heat recovery, particularly extracting heat from hot dry rock masses. The understanding of the fracture process under the ac tion of pressurized fluid at various temperatures is of fundamental scientific importance, which requires an adequate description of thermomechanical properties of subsurface rock, fluid-solid interaction effects, as well as degradation of the host rock due to temperature gradients introduced by heat extraction. Considerable progress has been made over the past several years in laboratory experiments, analytical and numerical modeling, and in-situ field studies in various aspects of hydraulic fracturing and geothermal energy extraction, by researchers in the United States and Japan and also elsewhere. However, the results have been scattered throughout the literature. Therefore, the time seemed ripe for bringing together selected researchers from the two countries, as well as observers from other countries, in order to survey the state of the art, exchange scientific information, and establish closer collaboration for further, better coordinated scientific effort in this important area of research and exploration.
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:
Download or read book Temporary Cementitious Sealers in Enhanced Geothermal Systems written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at H"0 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures e"00 C, present in H" km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when e"200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper-try sealers. Two specific additives without sodium silicate as alkaline additive were developed in this project: One additive was the sodium carboxymethyl cellulose (CMC) as self-degradation promoting additive; the other was the hard-burned magnesium oxide (MgO) made from calcinating at 1,000-1,500 C as an expansive additive. The AASC and AASF cementitious sealers made by incorporating an appropriate amount of these additives met the following six criteria: 1) One dry mix component product; 2) plastic viscosity, 20 to 70 cp at 300 rpm; 3) maintenance of pumpability for at least 1 hour at 85 C; 4) compressive strength>2000 psi; 5) self-degradable by injection with water at a certain pressure; and 6) expandable and swelling properties; e".5% of total volume of the sealer.
Download or read book Analysis of Reservoir Fracture Sealing in an Active Geothermal System Kawerau Geothermal Field New Zealand written by Aaron J. Lister and published by . This book was released on 2018 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Earth s Crust written by John G. Heacock and published by American Geophysical Union. This book was released on 1977 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rock Fractures and Fluid Flow written by National Research Council and published by National Academies Press. This book was released on 1996-08-27 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientific understanding of fluid flow in rock fracturesâ€"a process underlying contemporary earth science problems from the search for petroleum to the controversy over nuclear waste storageâ€"has grown significantly in the past 20 years. This volume presents a comprehensive report on the state of the field, with an interdisciplinary viewpoint, case studies of fracture sites, illustrations, conclusions, and research recommendations. The book addresses these questions: How can fractures that are significant hydraulic conductors be identified, located, and characterized? How do flow and transport occur in fracture systems? How can changes in fracture systems be predicted and controlled? Among other topics, the committee provides a geomechanical understanding of fracture formation, reviews methods for detecting subsurface fractures, and looks at the use of hydraulic and tracer tests to investigate fluid flow. The volume examines the state of conceptual and mathematical modeling, and it provides a useful framework for understanding the complexity of fracture changes that occur during fluid pumping and other engineering practices. With a practical and multidisciplinary outlook, this volume will be welcomed by geologists, petroleum geologists, geoengineers, geophysicists, hydrologists, researchers, educators and students in these fields, and public officials involved in geological projects.
Download or read book Materials Challenges in Alternative and Renewable Energy II written by George Wicks and published by John Wiley & Sons. This book was released on 2013-01-03 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall efficiency, effectiveness, and practicality of potential future energy sources and systems are directly related to many materials-related factors. This volume features 30 papers presented during the 2012 Materials Challenges in Alternative and Renewable Energy Conference. They cover the latest developments involving materials for alternative and renewable energy sources and systems, including batteries and energy storage, hydrogen, solar, wind, geothermal, biomass, and nuclear, as well as materials availability, the energy grid, and nanocomposites.
Download or read book Thermo Hydro Mechanical Coupling in Fractured Rock written by Hans-Joachim Kümpel and published by Birkhäuser. This book was released on 2012-12-06 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: (4). The next three papers extend these views by taking a closer look on parameters that govern hydraulic diffusivity in sandstones and other types of rocks. Specific targets addressed are the influence of differential stress on permeability (5), imaging of the fracture geometry (6), and pressure induced variations in the pore geometry (7). Contributions no. 8 to 10 cover investigations of permeability-porosity relationships during rock evolution (8), of the formation, propagation, and roughness of fractures in a plexi-glass block (9), and pressure oscillation effects of two-phase flow under controlled conditions (10). The subsequent four articles focus on diverse modeling approaches. Issues considered are how the geometry and the mechanical behavior of fractures can be characterized by mathematical expressions (11), how the evolution of permeability in a microcracking rock can be expressed by an analytical model (12), deviations from the cubic law for a fracture of varying aperture (13), and the numerical simulation of scale effects in flow through fractures (14). Three further papers refer to in situ observations, being related to topics as the assessment of in situ permeability from the spatio temporal distribution of an aftershock sequence (15), to the scale dependence of hydraulic pathways in crystalline rock (16), and to the significance of pore pressure - stress coupling in deep tunnels and galleries (17).
Download or read book The Initiation Propagation and Arrest of Joints and Other Fractures written by John W. Cosgrove and published by Geological Society of London. This book was released on 2004 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a state of the art look at our understanding of joint development in the crust. Answers are provided for such questions as the mechanisms by which joints are initiated, the factors controlling the path they follow during the propagation process, and the processes responsible for the arrest of joints. Many of the answers to these questions can be inferred from the geometry of joint surface morphology and joint patterns. Joints are a record of the orientation of stress at the time of propagation and as such they are also useful records of ancient stress fields, regional and local. Because outcrop and subsurface views of joints are limited, statistical techniques are required to characterize joints and joint sets. Finally, joints are subject to post-propagation stresses that further localize deformation and are the focus for the development of new structures.
Download or read book Hydraulic fracturing and geothermal energy written by S. Nemat-Nassar and published by Springer. This book was released on 1983-07-31 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing has been and continues to be a major techno logical tool in oil and gas recovery, nuclear and other waste disposal, mining and particularly in-situ coal gasification, and, more recently, in geothermal heat recovery, particularly extracting heat from hot dry rock masses. The understanding of the fracture process under the ac tion of pressurized fluid at various temperatures is of fundamental scientific importance, which requires an adequate description of thermomechanical properties of subsurface rock, fluid-solid interaction effects, as well as degradation of the host rock due to temperature gradients introduced by heat extraction. Considerable progress has been made over the past several years in laboratory experiments, analytical and numerical modeling, and in-situ field studies in various aspects of hydraulic fracturing and geothermal energy extraction, by researchers in the United States and Japan and also elsewhere. However, the results have been scattered throughout the literature. Therefore, the time seemed ripe for bringing together selected researchers from the two countries, as well as observers from other countries, in order to survey the state of the art, exchange scientific information, and establish closer collaboration for further, better coordinated scientific effort in this important area of research and exploration.
Download or read book Porosity Permeability and Fluid Flow in the Yellowstone Geothermal System Wyoming written by Patrick F. Dobson and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cores from two of 13 U.S. Geological Survey research holes at Yellowstone National Park (Y-5 and Y-8) were evaluated to characterize lithology, texture, alteration, and the degree and nature of fracturing and veining. Porosity and matrix permeability measurements and petrographic examination of the cores were used to evaluate the effects of lithology and hydrothermal alteration on porosity and permeability. The intervals studied in these two core holes span the conductive zone and the upper portion of the convective geothermal reservoir. Variations in porosity and matrix permeability observed in the Y-5 and Y-8 cores are primarily controlled by lithology. Y-8 intersects three distinct lithologies: volcaniclastic sandstone, perlitic rhyolitic lava, and non-welded pumiceous ash-flow tuff. The sandstone typically has high permeability and porosity, and the tuff has very high porosity and moderate permeability, while the perlitic lava has very low porosity and is essentially impermeable. Hydrothermal self-sealing appears to have generated localized permeability barriers within the reservoir. Changes in pressure and temperature in Y-8 correspond to a zone of silicification in the volcaniclastic sandstone just above the contact with the perlitic rhyolite; this silicification has significantly reduced porosity and permeability. In rocks with inherently low matrix permeability (such as densely welded ash-flow tuff), fluid flow is controlled by the fracture network. The Y-5 core hole penetrates a thick intracaldera section of the 0.6-Ma Lava Creek ash-flow tuff. In this core, the degree of welding appears to be responsible for most of the variations in porosity, matrix permeability, and the frequency of fractures and veins. Fractures are most abundant within the more densely welded sections of the tuff. However, the most prominent zones of fracturing and mineralization are associated with hydrothermal breccias within densely welded portions of the tuff. These breccia zones represent transient conduits of high fluid flow that formed by the explosive release of overpressure in the underlying geothermal reservoir and that were subsequently sealed by supersaturated geothermal fluids. In addition to this fracture sealing, hydrothermal alteration at Yellowstone appears generally to reduce matrix permeability and focus flow along fractures, where multiple pulses of fluid flow and self-sealing have occurred.
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.
Download or read book Geothermal Reservoir Engineering written by Malcolm Alister Grant and published by Academic Press. This book was released on 2011-04-01 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate. For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference. This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The book focuses particularly on the evaluation of potential sites and provides detailed guidance on the field management of the power plants built on them. With over 100 pages of new material informed by the breakthroughs of the last 25 years, Geothermal Reservoir Engineering remains the only training tool and professional reference dedicated to advising both new and experienced geothermal reservoir engineers. - The only resource available to help geothermal professionals make smart choices in field site selection and reservoir management - Practical focus eschews theory and basics- getting right to the heart of the important issues encountered in the field - Updates include coverage of advances in EGS (enhanced geothermal systems), well stimulation, well modeling, extensive field histories and preparing data for reservoir simulation - Case studies provide cautionary tales and best practices that can only be imparted by a seasoned expert
Download or read book Challenges for Designing Closed loop Geothermal Systems written by Sai Liu and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Closed-loop geothermal systems (CLGS) are a novel heat extraction technique not requiring continuous fluid supply. The mechanism controlling the efficiency of closed-loop systems has not been well analyzed, so it lacks theory basis to design them. Working fluid is circulated only inside the wellbore, so heat extraction efficiency can be limited, which brings challenges to extensive application of closed-loop systems. At high temperatures in geothermal reservoirs, polymer seals may experience thermal deformation and degradation, which could cause leaks of circulating fluid in the wellbore. To address these challenges, a systematic numerical study was first conducted to explore factors affecting heat extraction efficiency of closed-loop systems and approaches to improving the efficiency. Then, experimental work was conducted to develop high-temperature resistant polymer composites for sealing geothermal wells. With the finite element methods, a coupled three-dimensional model was established for a basic closed-loop geothermal system (CLGS) and an enhanced closed-loop geothermal system (ECLGS). Effects of critical design factors on heat extraction of CLGS were investigated quantitatively. Increasing the cement thermal conductivity enhances both produced fluid temperature and thermal power. The effect of cement thickness is correlated with the value of its thermal conductivity. As the circulation rate increases, the temperature of produced fluid decreases while thermal power increases asymptotically. Using a circulating fluid with high heat capacity would result in higher thermal power. A dimensionless analysis was conducted, through which two dimensionless numbers were derived to integrate the effects of different factors. With the dimensionless numbers, effects of different individual factors can be evaluated comprehensively, which brings convenience to parameter design. Heat extraction through the ECLGS was also simulated. The objective of the ECLGS is to increase the heat transfer rate from rock to working fluid by thermally-conductive fractures connected to the wellbore. Simulation results suggest that fractures could improve heat extraction performance of the system noticeably. There exists a critical fluid circulation rate beyond which net power starts to decrease. To further improve heat extraction, a conductive plug along fractures was defined and incorporated in the system. The conductive plug could further improve heat extraction performance significantly. Effects of plug thermal conductivity, plug size, and plug shape were ascertained. Finally, a dimensionless analysis was also performed for ECLGS, through which three dimensionless numbers were derived to integrate different affecting factors. Then, polymer composites for sealing geothermal were developed by compounding treated graphite with ethylene propylene diene monomer (EPDM) rubber. First, the performances of two types of graphite, small-size lamellar graphite (SFG15) and graphite nanoplatelets (GNP), were studied. Second, the performance of high concentrations of treated SFG15 was examined. Experimental results show that treated SFG15 and GNP both enhance the temperature resistance of EPDM by over 80°C. High concentrations (9 wt.%) of treated graphite remarkably enhances the storage modulus of and reduces the loss factor (tan [delta]) of EPDM at high temperatures. Adding treated graphite significantly enhances the specific heat capacity of EPDM and remarkably increases heat energy required to melt it. The onset degradation temperature of EPDM-SFG15 nanocomposites is up to 30 °C higher than that of plain EPDM. In this dissertation, the mechanism controlling performance of closed-loop systems and approaches to improving the performance were explored. The developed polymer nanocomposites, with enhanced mechanical and thermal properties, are a promising candidate for the material used to seal closed-loop geothermal wells. The results and conclusions achieved in this dissertation may provide a reference for optimally designing closed-loop systems.
Download or read book Issues Surrounding Fracturing of Geothermal Systems written by Daniel Brinton and published by . This book was released on 2011 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geologic Fundamentals of Geothermal Energy written by David R. Boden and published by CRC Press. This book was released on 2016-09-19 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geothermal energy stands out because it can be used as a baseload resource. This book, unlike others, examines the geology related to geothermal applications. Geology dictates (a) how geothermal resources can be found, (b) the nature of the geothermal resource (such as liquid- or vapor-dominated) and (c) how the resource might be developed ultimately (such as flash or binary geothermal plants). The compilation and distillation of geological elements of geothermal systems into a single reference fills a notable gap.
