Download or read book Modeling of Heat Extraction from Variably Fractured Porous Media in Enhanced Geothermal Systems written by and published by . This book was released on 2016 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling of heat extraction in Enhanced Geothermal Systems is presented. The study builds on recent studies on the use of directional wells to improve heat transfer between doublet injection and production wells. The current study focuses on the influence of fracture orientation on production temperature in deep low permeability geothermal systems, and the effects of directional drilling and separation distance between boreholes on heat extraction. The modeling results indicate that fracture orientation with respect to the well-pair plane has significant influence on reservoir thermal drawdown. As a result, the vertical well doublet is impacted significantly more than the horizontal well doublet.

Download or read book Geoenergy Modeling III written by Norihiro Watanabe and published by Springer. This book was released on 2016-11-10 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on numerical modeling of deep hydrothermal and petrothermal systems in fractured georeservoirs for utilization in Geothermal Energy applications. The authors explain the particular challenges and approaches to modeling heat transport and high-throughput flow in multiply fractured porous rock formations. In order to help readers gain a system-level understanding of the necessary analysis, the authors include detailed examples of growing complexity as the techniques explained in the text are introduced. The coverage culminates with the fully-coupled analysis of real deep geothermal test-sites located in Germany and France.

Download or read book Computational Science ICCS 2019 written by João M. F. Rodrigues and published by Springer. This book was released on 2019-06-07 with total page 675 pages. Available in PDF, EPUB and Kindle. Book excerpt: The five-volume set LNCS 11536, 11537, 11538, 11539 and 11540 constitutes the proceedings of the 19th International Conference on Computational Science, ICCS 2019, held in Faro, Portugal, in June 2019. The total of 65 full papers and 168 workshop papers presented in this book set were carefully reviewed and selected from 573 submissions (228 submissions to the main track and 345 submissions to the workshops). The papers were organized in topical sections named: Part I: ICCS Main Track Part II: ICCS Main Track; Track of Advances in High-Performance Computational Earth Sciences: Applications and Frameworks; Track of Agent-Based Simulations, Adaptive Algorithms and Solvers; Track of Applications of Matrix Methods in Artificial Intelligence and Machine Learning; Track of Architecture, Languages, Compilation and Hardware Support for Emerging and Heterogeneous Systems Part III: Track of Biomedical and Bioinformatics Challenges for Computer Science; Track of Classifier Learning from Difficult Data; Track of Computational Finance and Business Intelligence; Track of Computational Optimization, Modelling and Simulation; Track of Computational Science in IoT and Smart Systems Part IV: Track of Data-Driven Computational Sciences; Track of Machine Learning and Data Assimilation for Dynamical Systems; Track of Marine Computing in the Interconnected World for the Benefit of the Society; Track of Multiscale Modelling and Simulation; Track of Simulations of Flow and Transport: Modeling, Algorithms and Computation Part V: Track of Smart Systems: Computer Vision, Sensor Networks and Machine Learning; Track of Solving Problems with Uncertainties; Track of Teaching Computational Science; Poster Track ICCS 2019 Chapter “Comparing Domain-decomposition Methods for the Parallelization of Distributed Land Surface Models” is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

Download or read book Geoenergy Modeling I written by Norbert Böttcher and published by Springer. This book was released on 2016-06-27 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introduction to geothermal modeling deals with flow and heat transport processes in porous and fractured media related to geothermal energy applications. Following background coverage of geothermal resources and utilization in several countries, the basics of continuum mechanics for heat transport processes, as well as numerical methods for solving underlying governing equations are discussed. This examination forms the theoretical basis for five included step-by-step OpenGeoSys exercises, highlighting the most important computational areas within geothermal resource utilization, including heat diffusion, heat advection in porous and fractured media, and heat convection. The book concludes with an outlook on practical follow-up contributions investigating the numerical simulation of shallow and deep geothermal systems.

Download or read book Modeling of Non equilibrium Heat Transfer in a Fractured Porous Medium for Enhanced Geothermal Systems Applications written by and published by . This book was released on 2012 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Convective Heat Transfer in Porous Media written by Yasser Mahmoudi and published by CRC Press. This book was released on 2019-11-06 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on heat transfer in porous media, this book covers recent advances in nano and macro’ scales. Apart from introducing heat flux bifurcation and splitting within porous media, it highlights two-phase flow, nanofluids, wicking, and convection in bi-disperse porous media. New methods in modeling heat and transport in porous media, such as pore-scale analysis and Lattice–Boltzmann methods, are introduced. The book covers related engineering applications, such as enhanced geothermal systems, porous burners, solar systems, transpiration cooling in aerospace, heat transfer enhancement and electronic cooling, drying and soil evaporation, foam heat exchangers, and polymer-electrolyte fuel cells.

Download or read book Heat Transfer Investigations for Optimal Harnessing of Enhanced Geothermal Systems written by Esuru Rita Okoroafor and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced Geothermal Systems (EGS) offer the opportunity of exploiting the vast energy resources contained in hot impermeable rocks. In such rocks, the natural flow capacity of the system may not be sufficient to support adequate geothermal applications until it is enhanced by opening up existing fractures and propagating new fractures. Cold fluid is injected into the reservoir to exploit the energy resource, whose permeability has been enhanced. The increased permeability allows the fluid to circulate through the opened fractures to production or extraction well(s), thereby capturing and transporting the heat contained in the hot impermeable rock for power generation. Accurate prediction of the thermal performance of EGS depends on an understanding of how the heat transport is affected by the presence of the fracture(s) -- the primary flow conduit of EGS. These fractures may have aperture variability that could create channels and alter flow paths, affecting the availability of surface area for heat transfer. The overall goal of this study was to understand the fracture topology, investigate how it can impact flow and heat transport, and demonstrate ways Enhanced Geothermal Systems can be harnessed to optimize thermal performance. To achieve the goal of this study, a systematic fracture characterization approach was used, and numerical simulation models were used to study the physical processes that govern the interaction between the fluid and the rock during heat extraction from Enhanced Geothermal Systems. Using variogram modeling and Sequential Gaussian Simulation method, fracture apertures representing actual fractures were generated for lab-scale and field-scale investigations. Fracture characterization metrics such as the Joint Roughness Coefficient (JRC) and Hurst exponent were used in analyzing the data. Geometric anisotropy was a vital character of the generated fracture aperture distributions, which was seen to originate from the process of shearing or slip. Flow and heat transport relative to the direction of fracture shear was studied, with the perpendicular flow configuration being perpendicular to the direction of fracture shear. In contrast, the parallel flow configuration had flow in the same direction as the fracture shear direction. It was demonstrated in this study that the flow wetted surface area had a direct and significant contribution to the amount of heat extracted. For the lab-scale fractures, the JRC confirmed geometric anisotropy of the fracture aperture and was seen to have a direct correlation with the flow contact area. The lower the difference in JRC values between the perpendicular and parallel flow configurations, the more flow contact area expected in the perpendicular flow direction, which will lead to more heat extracted from the rock. From the variogram model parameters, it was deduced that high geometric anisotropy results in high differences in thermal drawdown and consequently a high difference in energy extracted. The thermal performance appeared to be better in the perpendicular flow configuration with a ratio of 70:30 for the lab-scale fractures. For the field-scale fractures, it was seen that most of the fracture aperture distributions with a geometric anisotropy ratio of 2 had Hurst exponents of fracture surface aperture variability found in nature. For all the fracture aperture distributions analyzed for the field scale, the perpendicular flow configuration resulted in better thermal performance than the parallel flow configuration with a ratio of 58:42. Furthermore, for the geometric anisotropy ratio of 2, the ratio was 70:30. The perpendicular flow configuration had the injected fluid move through tortuous flow paths. These tortuous flow paths contributed to more fracture surface area being contacted by the flowing fluid, leading to an improved thermal performance in that flow configuration. Throughout this study, temperature-dependent viscosity was used. However, a section of this study investigated the impact of using a constant viscosity in the thermohydraulic model. It was seen that for fractures with smooth, uniform apertures, for all temperature ranges and at the operating conditions being modeled, there was no significant difference between using a constant viscosity or a temperature-dependent viscosity in modeling an Enhanced Geothermal System. However, for fractures with spatial variations, it was determined that modeling with a temperature-dependent viscosity was necessary, especially for systems with high differences in reservoir and injection temperatures, and for fractures with high correlation lengths. The impact of thermal stresses on heat extraction was also investigated. An analog Enhanced Geothermal System, the Altona Field Laboratory, was also studied for thermo-mechanical influences. It was found out that the injection of hot water into the cold rock resulted in thermal stress generation and reduction in the aperture but did not cause significant changes to the temperature profile due to the small volumetric flow rate through the system. Also, anisotropic aperture distributions were studied to determine the impact of thermoelasticity on the heat extraction of Enhanced Geothermal Systems. It was shown that when thermoelasticity is taken into consideration, the thermal drawdown could either be improved or deteriorated depending on the nature of the aperture distribution. The impact of fracture aperture variability was investigated for Enhanced Geothermal Systems using supercritical CO2 as working fluids. It was established that CO2 as an EGS working fluid would result in better heat extracted from the system if the fractures are considered smooth, which agrees with related studies. However, where there is spatial variation in the fracture aperture, channeling could be detrimental to CO2, especially at high fracture correlation lengths and high mass flow rates, due to the high mobility of CO2. The following are the main contributions from this study. First, it has been demonstrated that heat transport is affected by the geometric anisotropy of fracture surfaces. It was determined that in most cases, flowing perpendicular to the direction of shear or slip results in more heat extracted due to more contact of the fluid with the rock while moving through tortuous flow paths. Secondly, the conditions under which a constant viscosity can be used in modeling EGS were determined. If the fractures are known to be smooth, have low correlation lengths, or have distributed surface areas, a constant viscosity can be used in the model, especially if the difference between the reservoir temperature and the injection water temperature is small. However, for anisotropic fracture surfaces, surfaces with high correlations lengths or high tortuosity, and when the difference between the reservoir temperature and injection water temperature is large, the use of constant viscosity could result in significant computational errors from the actual. Thirdly, it has been shown that thermal drawdown could either be improved or deteriorate when thermoelasticity is considered. This finding is different from studies previous studies that have looked into coupling thermohydromechanical processes for fractures with spatial variations and suggests that Enhanced Geothermal Systems may benefit from thermal stimulation. Finally, this work shows the first comparison between CO2 and water at a field scale considering fracture aperture variability. Recommended future work includes modeling of vertical fractures with spatial variations in fracture aperture to investigate how convection may impact the current findings; considering multiple fractures with spatial variations in the fracture aperture; considering non-Darcy flow in the simulation models; coupling geomechanics with the study of CO2 on fractures with spatial variations, and developing proxy models that are quicker to perform the thermohydraulic and thermohydromechanical simulations.

Download or read book Mathematical Modeling of Fluid Flow and Heat Transfer in Petroleum Industries and Geothermal Applications written by Mehrdad Massoudi and published by MDPI. This book was released on 2020-04-16 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geothermal energy is the thermal energy generated and stored in the Earth's core, mantle, and crust. Geothermal technologies are used to generate electricity and to heat and cool buildings. To develop accurate models for heat and mass transfer applications involving fluid flow in geothermal applications or reservoir engineering and petroleum industries, a basic knowledge of the rheological and transport properties of the materials involved (drilling fluid, rock properties, etc.)—especially in high-temperature and high-pressure environments—are needed. This Special Issue considers all aspects of fluid flow and heat transfer in geothermal applications, including the ground heat exchanger, conduction and convection in porous media. The emphasis here is on mathematical and computational aspects of fluid flow in conventional and unconventional reservoirs, geothermal engineering, fluid flow, and heat transfer in drilling engineering and enhanced oil recovery (hydraulic fracturing, CO2 injection, etc.) applications.

Download or read book Computational Modeling of Shallow Geothermal Systems written by Rafid Al-Khoury and published by CRC Press. This book was released on 2011-09-30 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Step-by-step Guide to Developing Innovative Computational Tools for Shallow Geothermal SystemsGeothermal heat is a viable source of energy and its environmental impact in terms of CO2 emissions is significantly lower than conventional fossil fuels. Shallow geothermal systems are increasingly utilized for heating and cooling of buildings and green

Download or read book Thermal Hydraulic Modeling of Discretely Fractured Geothermal Reservoirs written by Don Bruce Fox and published by . This book was released on 2016 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced/Engineered Geothermal Systems (EGS) have the potential to provide a significant amount of base load electricity and heat and to displace fossil fuel consumption globally. To determine the potential for the expansion of direct use geothermal energy, a detailed analysis of U.S. energy consumption was performed to estimate the amount of primary energy consumed as a function of its utilization temperature from 0 to 260? C. The analysis revealed that about 34 EJ annually, more than 30% of the U.S. annual energy demand is used for direct thermal use applications in the temperature range of 0 to 260? C. Both analytical and numerical models of discretely fractured reservoirs were developed to probe the thermal hydraulic behavior of model EGS reservoirs and quantify factors controlling performance. An analytical model for discrete, fixed aperture, rectangular fractures with specified uniform flow was used to illustrate the renew ability of EGS reservoirs with a ratio of production to renewal times of about 0.2 to 0.33. Fracture structure and connectivity were also shown to affect reservoir performance in modeling studies. In general, fracture connectivity is more important than aperture variations within the fractures. Flow channeling in fractures with spatially varying aperture fields were simulated using a developed numerical model. An ensemble of fracture realizations were used to illustrate how the magnitude of aperture variations lead to flow structures that often inhibit rather than enhance subsurface heat exchange. Finally, both conservative and reactive tracers were used to determine the spatially varying thermal field during heat extraction in a discrete fracture with variable aperture. Reduced order modeling of the fracture was used to create a tractable framework for inferring reservoir structure. Tracers revealed the capability to predict a reservoir's production temperature versus time, with reactive tracers providing better results. However, difficulties in accurately predicting the aperture field led to a non-unique outcome where more than one reservoir realization matched both the tracer curve and production temperature.

Download or read book Heat Mining written by H. Christopher H. Armstead and published by Spon Press. This book was released on 1987 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Very Good,No Highlights or Markup,all pages are intact.

Download or read book Structurally Complex Reservoirs written by S. J. Jolley and published by Geological Society of London. This book was released on 2007 with total page 508 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 Numerical Modeling of an Enhanced Geothermal System with High Permeability in Kizildere Field Turkey written by Burak Firat and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geothermal energy has the potential to be a key player in energy transformation all over the world through Enhanced Geothermal Systems (EGS). This study evaluates the energy production from the geothermal reservoir located in the Kizildere field in Turkey in conjunction with analytical and numerical approaches. Moreover, this work investigates the impact of natural fracture networks in this high-permeability field. First, the Kizildere field data were evaluated, and then the data were analyzed for energy production for 50 years by applying a few analytical models. The field was simulated for 50 years using CMG Thermal STARS with a novel code, thermal Embedded Discrete Fracture Model (EDFM). The simulations analyzed the effects of different well designs on heat generation. Sensitivity analysis was by using various natural fracture network densities. The results show that the number of natural fractures in high permeable reservoirs does not impact the amount of heat extraction because the circulation fluid mainly flows through the matrix instead of fractures in EGS with high permeability. In addition, this thesis shows that the impact of well placement primarily depends on reservoir dimensions. Additional work was done regarding the effect of high temperature in the selection of casing. Furthermore, the thesis delivers forecasts and possible recommendations for further research

Download or read book Modeling Density Driven Flow in Porous Media written by Ekkehard O. Holzbecher and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling of flow and transport in groundwater has become an important focus of scientific research in recent years. Most contributions to this subject deal with flow situations, where density and viscosity changes in the fluid are neglected. This restriction may not always be justified. The models presented in the book demonstrate immpressingly that the flow pattern may be completely different when density changes are taken into account. The main applications of the models are: thermal and saline convection, geothermal flow, saltwater intrusion, flow through salt formations etc. This book not only presents basic theory, but the reader can also test his knowledge by applying the included software and can set up own models.

Download or read book Numerical Investigations of Conjugate Porous Media Model written by Putra Hanif Agson Gani and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Predicting the conjugate heat transfer and fluid flow behavior in porous media is still a challenging research area in many applications due to the complex nature of the flow. This thesis is divided into three topics. The first two topics focus on the numerical modeling of conjugate porous media in the mine ventilation network and geothermal heat exchanger settings. The third topic solves the expensive computational cost of the previous topics by developing a reduced-order semi conjugate heat transfer model for a double-pipe heat exchanger. In the first part of the thesis, conjugate porous media in mine ventilation network is discussed. The porous media is formed as a broken rock structure which is created due to the mining operations (e.g., blasting and hauling). In this thesis, a novel friction factor correlation which describes the effect of porous zone in the model is integrated into the mine ventilation network software which solves a one-dimensional model. The correlation accuracy is verified with three-dimensional computational fluid dynamic models. In the second part of the thesis, conjugate porous media is applied to enhance the heat transfer performance of the closed-loop double-pipe geothermal heat exchanger. The porous zone was created at the bottom of the well with the hydraulic fracturing process, and fractal theory is implemented to emulate the tree-like porous structure. The results suggest that this novel geothermal heat exchanger design improves the heat extraction rate by 90%, which indicates the potential of the implementation of this design. Both conjugate porous media applications in mine ventilation networks and geothermal heat exchangers are numerically investigated based on conservation equations of mass, momentum, and energy in a three-dimensional (3D) model and two-dimensional (2D) axisymmetric model, respectively. However, numerical modeling of these systems could be computationally expensive due to its typical large domains and long operational time. Therefore, in the third part of the thesis, a novel computationally efficient one-plus-one-dimensional (1+1D) semi-conjugate heat transfer model is proposed. The proposed model solves the transient conservation equation of energy in radial coordinate coupled with the space marching algorithm to save computational time and cost. Lastly, thermal superposition theory is also implemented to expand the single borehole model into double boreholes and 3-by-3 boreholes"--

Download or read book Fluid Flow in Fractured Porous Media written by Richeng Liu and published by MDPI. This book was released on 2019-09-30 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fluid flow in fracture porous media plays a significant role in the assessment of deep underground reservoirs, such as through CO2 sequestration, enhanced oil recovery, and geothermal energy development. Many methods have been employed—from laboratory experimentation to theoretical analysis and numerical simulations—and allowed for many useful conclusions. This Special Issue aims to report on the current advances related to this topic. This collection of 58 papers represents a wide variety of topics, including on granite permeability investigation, grouting, coal mining, roadway, and concrete, to name but a few. We sincerely hope that the papers published in this Special Issue will be an invaluable resource for our readers.