Download or read book Investigation of Hydraulic Fracturing in Dams Using the Finite Element Method written by Kwok Leung Axel Ng and published by . This book was released on 1996 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydraulic Fracturing in Earth rock Fill Dams written by Jun-Jie Wang and published by John Wiley & Sons. This book was released on 2014-08-11 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a systematic and comprehensive study of hydraulic fracturing, original in its concentration of core soil problems There have been a number of well-studied cases in which dams have failed or been damaged by concentrated leaks for no apparent cause. In some of these experiences, investigators concluded that differential settlement cracks were the probable causes, even though no cracks were seen on the surface. In these examples, it was not determined whether the crack was open before the reservoir filled or whether it might have opened afterward. In several unsolved problems on the safety of the earth-rock fill dam, the problem of hydraulic fracture in the soil core of the earth-rock fill dam is one that is widely paid attention by designers and researchers. Hydraulic fracturing is generally considered as a key cause which may induce the leakage of the dam during first filling. In this extensive book, a new numerical simulate method is suggested. The method is based on the conventional two-dimensional finite element technique, and the theoretical formulations to calculate energy release rate using virtual crack extension method. The influence factors on convergence of calculated J integral are investigated. The accuracy of the calculated J integral is verified by analysing the three typical problems in Fracture Mechanics, in which propagation of crack may follow mode I, mode II and mixed mode I-II respectively. Using the new numerical method, the factors affecting the occurrence of hydraulic fracturing in the earth-rock fill dam are investigated. The investigating results indicate that increasing any of the Young’s modulus, the Poisson’s ratio and the density of the core soil is helpful to reduce the likelihood of the occurrence of hydraulic fracturing. The likelihood of the occurrence of hydraulic fracturing increases with increasing the water level or the crack depth. The lower part of the dam core is the zone in which the phenomenon of hydraulic fracturing may be induced easily. As an example to analyse the ability of earth-rock fill dam to resist hydraulic fracturing, the Nuozhadu Dam located in Western China is analysed. Presents a systematic and comprehensive study of hydraulic fracturing, original in its concentration of core soil problems Focuses on the problem of hydraulic fracturing in earth-rock fill dams from three aspects; conditions and mechanisms of hydraulic fracturing, criterion of hydraulic fracturing, and numerical method on hydraulic fracturing Examines advanced laboratory soil testing, application of numerical methods and field testing/monitoring, all needed for a better understanding of hydraulic fracturing in earth/rock fill dams Provides an essential reference in an area of scarce research in this field, and the need in high earth dam construction in developing countries is pressing Ideal for researchers in Hydraulic and Geotechnical Engineering Fields; Students on Masters or PhD courses; as well as Designers and Constructors in Hydraulic and Geotechnical Engineering Fields.

Download or read book Analysis of the Potential for Hydraulic Fracturing in a Dam with Core by the Finite Element Methods of SIGMA W SEEP W written by Sang-Hoon Roh and published by . This book was released on 1996 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Developments in Dam Engineering written by Martin Wieland and published by CRC Press. This book was released on 2014-05-14 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of water resources is a key element in the socio-economic development of many regions in the world. Water availability and rainfall are unequally distributed both in space and time, so dams play a vital role, there being few viable alternatives for storing water. Dams hold a prime place in satisfying the ever-increasing demand for power, irrigation and drinking water, for protection of man, property and environment from catastrophic floods, and for regulating the flow of rivers. Dams have contributed to the development of civilization for over 2,000 years. Worldwide there are some 45,000 large dams listed by ICOLD, which have a height over 15 meters. Today, in western countries, where most of the water resources have been developed, the safety of the existing dams and measures for extending their economical life are of prime concern. In developing countries the focus is on the construction of new dams. The proceedings of the 4th International Conference on Dam Engineering includes contributions from 18 countries, and provides an overview of the state-of-the-art in hydropower development, new type dams, new materials and new technologies, dam and environment. Traditional areas, such as concrete dams and embankment dams, methods of analysis and design of dams, dam foundation, seismic analysis, design and safety, stability of dam and slope, dam safety monitoring and instrumentation, dam maintenance, and rehabilitation and heightening are also considered. The book is of special interest to scientists, researchers, engineers, and students working in dam engineering, dam design, hydropower development, environmental engineering, and structural hydraulics.

Download or read book Three dimensional Finite Element Analysis of New Melones Dam written by United States. Army. Corps of Engineers. Sacramento District and published by . This book was released on 1976 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Finite Element Techniques in Groundwater Flow Studies written by I. Kazda and published by Elsevier. This book was released on 2012-12-02 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The finite element method (FEM) is one of those modern numerical methods whose rise and development was incited by the rapid development of computers. This method has found applications in all the technical disciplines as well as in the natural sciences.One of the most effective applications of the finite element method is its use for the solution of groundwater flow problems encountered in the design and maintenance of hydraulic structures and tailing dams, in soil mechanics, hydrology, hydrogeology and engineering geology.The stimuli to write this book came from the results obtained in the solution of practical problems connected both with the construction and maintenance of fill-type dams and tailing dams and the utilization of groundwater in Czechoslovakia, and on the other hand from the experience gained in teaching hydraulic structures theory at the Faculty of Civil Engineering of the Technical University of Prague. All the experience so far obtained shows markedly the advantages of the finite element method and the great possibilities of its further development as well as its considerable demands on the algorithmization, programming and use of computer possibilities. The reader will find an explanation of the fundamentals of the finite element method directed mainly toward isoparametric elements having an exceptional adaptability and numerical reliability. The finite element method application to groundwater flow concerns mainly two-dimensional problems, which occur most frequently in practice. Considerable attention is given to non-linear and non-stationary problems, which are most important in application.A computer program (based on the eight-noded isoparametric elements) is included and fully documented.The book will be useful to civil engineers, hydrogeologists and engineering geologists who need the finite element method as a solution tool for the complex problems encountered in engineering practice.

Download or read book Hydraulic Fracturing in Zoned Earth and Rockfill Dams written by E. S. Nobari and published by . This book was released on 1973 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation involves two parts: first, an experimental investigation to study the phenomenon of hydraulic fracturing under carefully controlled laboratory conditions; and second, an analytical investigation to determine the conditions under which the stresses in the cores of zoned dams may be reduced sufficiently by arching so that hydraulic fracturing can occur. Analyses were also performed to examine the effectiveness of various countermeasures which can reduce the arching and the likelihood of hydraulic fracturing.

Download or read book Hydraulic Fracture Modeling written by Yu-Shu Wu and published by Gulf Professional Publishing. This book was released on 2017-11-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic Fracture Modeling delivers all the pertinent technology and solutions in one product to become the go-to source for petroleum and reservoir engineers. Providing tools and approaches, this multi-contributed reference presents current and upcoming developments for modeling rock fracturing including their limitations and problem-solving applications. Fractures are common in oil and gas reservoir formations, and with the ongoing increase in development of unconventional reservoirs, more petroleum engineers today need to know the latest technology surrounding hydraulic fracturing technology such as fracture rock modeling. There is tremendous research in the area but not all located in one place. Covering two types of modeling technologies, various effective fracturing approaches and model applications for fracturing, the book equips today’s petroleum engineer with an all-inclusive product to characterize and optimize today’s more complex reservoirs. Offers understanding of the details surrounding fracturing and fracture modeling technology, including theories and quantitative methods Provides academic and practical perspective from multiple contributors at the forefront of hydraulic fracturing and rock mechanics Provides today’s petroleum engineer with model validation tools backed by real-world case studies

Download or read book An Experimental Study of Hydraulic Fracturing written by Gary William Jaworski and published by . This book was released on 1979 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Modeling of Hydraulic Fracture Propagation Using Thermo hydro mechanical Analysis with Brittle Damage Model by Finite Element Method written by Kyoung Min and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Better understanding and control of crack growth direction during hydraulic fracturing are essential for enhancing productivity of geothermal and petroleum reservoirs. Structural analysis of fracture propagation and impact on fluid flow is a challenging issue because of the complexity of rock properties and physical aspects of rock failure and fracture growth. Realistic interpretation of the complex interactions between rock deformation, fluid flow, heat transfer, and fracture propagation induced by fluid injection is important for fracture network design. In this work, numerical models are developed to simulate rock failure and hydraulic fracture propagation. The influences of rock deformation, fluid flow, and heat transfer on fracturing processes are studied using a coupled thermo-hydro-mechanical (THM) analysis. The models are used to simulate microscopic and macroscopic fracture behaviors of laboratory-scale uniaxial and triaxial experiments on rock using an elastic/brittle damage model considering a stochastic heterogeneity distribution. The constitutive modeling by the energy release rate-based damage evolution allows characterizing brittle rock failure and strength degradation. This approach is then used to simulate the sequential process of heterogeneous rock failures from the initiation of microcracks to the growth of macrocracks. The hydraulic fracturing path, especially for fractures emanating from inclined wellbores and closed natural fractures, often involves mixed mode fracture propagation. Especially, when the fracture is inclined in a 3D stress field, the propagation cannot be modeled using 2D fracture models. Hence, 2D/3D mixed-modes fracture growth from an initially embedded circular crack is studied using the damage mechanics approach implemented in a finite element method. As a practical problem, hydraulic fracturing stimulation often involves fluid pressure change caused by injected fracturing fluid, fluid leakoff, and fracture propagation with brittle rock behavior and stress heterogeneities. In this dissertation, hydraulic fracture propagation is simulated using a coupled fluid flow/diffusion and rock deformation analysis. Later THM analysis is also carried out. The hydraulic forces in extended fractures are solved using a lubrication equation. Using a new moving-boundary element partition methodology (EPM), fracture propagation through heterogeneous media is predicted simply and efficiently. The method allows coupling fluid flow and rock deformation, and fracture propagation using the lubrication equation to solve for the fluid pressure through newly propagating crack paths. Using the proposed model, the 2D/3D hydraulic fracturing simulations are performed to investigate the role of material and rock heterogeneity. Furthermore, in geothermal and petroleum reservoir design, engineers can take advantage of thermal fracturing that occurs when heat transfers between injected flow and the rock matrix to create reservoir permeability. These thermal stresses are calculated using coupled THM analysis and their influence on crack propagation during reservoir stimulation are investigated using damage mechanics and thermal loading algorithms for newly fractured surfaces. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/150961

Download or read book Hydraulic Fracturing in Unconventional Reservoirs written by Hoss Belyadi and published by Gulf Professional Publishing. This book was released on 2019-06-18 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic Fracturing in Unconventional Reservoirs: Theories, Operations, and Economic Analysis, Second Edition, presents the latest operations and applications in all facets of fracturing. Enhanced to include today’s newest technologies, such as machine learning and the monitoring of field performance using pressure and rate transient analysis, this reference gives engineers the full spectrum of information needed to run unconventional field developments. Covering key aspects, including fracture clean-up, expanded material on refracturing, and a discussion on economic analysis in unconventional reservoirs, this book keeps today's petroleum engineers updated on the critical aspects of unconventional activity. Helps readers understand drilling and production technology and operations in shale gas through real-field examples Covers various topics on fractured wells and the exploitation of unconventional hydrocarbons in one complete reference Presents the latest operations and applications in all facets of fracturing

Download or read book Finite Element Analysis of Bi material Systems with Applications in Hydraulic Fracturing written by Oguzhan Gurdogan and published by . This book was released on 1984 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New numerical approaches to model hydraulic fracturing in tight reservoirs with consideration of hydro mechanical coupling effects written by Lei Zhou and published by Cuvillier Verlag. This book was released on 2014-03-20 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, two new numerical approaches for hydraulic fracturing in tight reservoir were developed. A more physical-based numerical 3D-model was developed for simulating the whole hydraulic fracturing process including fracture propagation, closure and contact as well as proppant transport and settling. In this approach rock formation, pore and fracture systems were assembled together, in which hydro-mechanical coupling effect, proppant transport and settling as well as their influences on fracture closure and contact were fully considered. A combined FDM and FVM schema was used to solve the problem. Three applications by using the new approach were presented. The results illustrated the whole hydraulic fracturing process well and seemed to be logical, which confirmed the ability of the developed approach to model the in-situ hydraulic fracturing operation from injection start till fully closure. In order to investigate the orientation problem of hydraulic fracturing in tight reservoir, a new approach for simulating arbitrary fracture propagation and orientation in 2D was developed. It was solved by a hybrid schema of XFEM and FVM. Three numerical studies were illustrated, which proved the ability of the developed approach to solve the orientation problem in field cases.

Download or read book Analysis of Hydraulic Fracture Propagation in Fractured Reservoirs written by Arash Dahi Taleghani and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large volumes of natural gas exist in tight fissured reservoirs. Hydraulic fracturing is one of the main stimulating techniques to enhance recovery from these fractured reservoirs. Although hydraulic fracturing has been used for decades for the stimulation of tight gas reservoirs, a thorough understanding of the interaction between induced hydraulic fractures and natural fractures is still lacking. Recent examples of hydraulic fracture diagnostic data suggest complex, multi-stranded hydraulic fracture geometry is a common occurrence. The interaction between pre-existing natural fractures and the advancing hydraulic fracture is a key condition leading to complex fracture patterns. Large populations of natural fractures that exist in formations such as the Barnett shale are sealed by precipitated cements which could be quartz, calcite, etc. Even though there is no porosity in the sealed fractures, they may still serve as weak paths for fracture initiation and/or for diverting the path of the growing hydraulic fractures. Performing hydraulic fracture design calculations under these complex conditions requires modeling of fracture intersections and tracking fluid fronts in the network of reactivated fissures. In this dissertation, the effect of the cohesiveness of the sealed natural fractures and the intact rock toughness in hydraulic fracturing are studied. Accordingly, the role of the pre-existing fracture geometry is also investigated. The results provide some explanations for significant differences in hydraulic fracturing in naturally fractured reservoirs from non-fractured reservoirs. For the purpose of this research, an extended finite element method (XFEM) code is developed to simulate fracture propagation, initiation and intersection. The motivation behind applying XFEM are the desire to avoid remeshing in each step of the fracture propagation, being able to consider arbitrary varying geometry of natural fractures and the insensitivity of fracture propagation to mesh geometry. New modifications are introduced into XFEM to improve stress intensity factor calculations, including fracture intersection criteria into the model and improving accuracy of the solution in near crack tip regions. The presented coupled fluid flow-fracture mechanics simulations extend available modeling efforts and provide a unified framework for evaluating fracture design parameters and their consequences. Results demonstrate that fracture pattern complexity is strongly controlled by the magnitude of in situ stress anisotropy, the rock toughness, the natural fracture cement strength, and the approach angle of the hydraulic fracture to the natural fracture. Previous studies (mostly based on frictional fault stability analysis) have concentrated on predicting the onset of natural fracture failure. However, the use of fracture mechanics and XFEM makes it possible to evaluate the progression of fracture growth over time as fluid is diverted into the natural fractures. Analysis shows that the growing hydraulic fracture may exert enough tensile and/or shear stresses on cemented natural fractures that they may be opened or slip in advance of hydraulic fracture tip arrival, while under some conditions, natural fractures will be unaffected by the hydraulic fracture. A threshold is defined for the fracture energy of cements where, for cases below this threshold, hydraulic fractures divert into the natural fractures. The value of this threshold is calculated for different fracture set orientations. Finally, detailed pressure profile and aperture distributions at the intersection between fracture segments show the potential for difficulty in proppant transport under complex fracture propagation conditions. Whether a hydraulic fracture crosses or is arrested by a pre-existing natural fracture is controlled by shear strength and potential slippage at the fracture intersections, as well as potential debonding of sealed cracks in the near-tip region of a propagating hydraulic fracture. We introduce a new more general criterion for fracture propagation at the intersections. We present a complex hydraulic fracture pattern propagation model based on the Extended Finite Element Method as a design tool that can be used to optimize treatment parameters under complex propagation conditions.

Download or read book Scale and Time Effects in Hydraulic Fracturing written by Hadi Widjaja and published by . This book was released on 1984 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to determine the effects of scale and time on hydraulic fracturing in compacted samples of Teton Dam silt and Pittsburg silty clay. A theory was developed to show how size of opening, time of pressurizing opening, and soil permeability are related to the occurrence of hydraulic fracturing. Finite element analyses were used to investigate the possible effects of nonlinear soil behavior. Both experimental and theoretical studies show that hydraulic fracturing can be initiated by seepage-induced forces without the presence of a preexisting flaw in the soil. (Author).

Download or read book 3 D Modeling of Interaction Between a Hydraulic Fracture and Multiple Natural Fractures Using Finite Element Analysis written by Debashish Talukder and published by . This book was released on 2019 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-layered, 3-D geo-mechanical model was developed using Finite Element Analysis (FEA) software (ABAQUS) to simulate single stage hydraulic fracturing treatment in a synthetic fractured model based on available shale information from literature. The main objectives of this study were- (i) to investigate the interaction between a hydraulic fracture (HF) orthogonally intersecting two parallel natural fractures (NF) and (ii) to identify significant parameters and their 2-factor interactions that affect HF propagation in the presence of multiple NFs. Based on literature review, an initial set of 20 parameters (a combination of geologic and drilling parameters) was selected. Those parameters were believed to affect the hydraulic fracture propagation in a naturally fractured model. Experiments were conducted in two stages. First-order order numerical experiments were conducted under the Plackett-Burman experimental design. Central Composite Design (CCD) was used to check curvature and to take care of non-linearity existing in the dataset. A stepwise sensitivity analysis and parametric study were conducted to identify significant parameters and their interactions. When the HF interacted with NFs, there were three possible outcomes- the HF either got arrested, dilated or crossed the NF. The overall hydraulic fracture geometry depended on the type of interaction behavior occurring at the intersection. The NF leakoff coefficient was the most significant factor in the 1st order experiments that affected the HF propagation in the presence of multiple NFs. CCD results suggested that NF strength at the bottom shale layer and injection fluid viscosity significantly influenced the HF opening in the presence of the natural fractures. The most significant two-factor interaction was the interaction between stress contrast and Young’s modulus of the overburden shale (Ytop). This study will help understand the interaction behavior between a HF and two pre-existing NFs. The parametric study will provide a valuable insight for hydraulic fracturing treatment in a naturally fractured formation.

Download or read book Modelling of Hydraulic Fracturing and Its Engineering Application written by Kenneth Imo-Imo Eshiet and published by . This book was released on 2012 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hydraulic Fracturing process and its engineering applications have been studied and reported in this thesis. The Distinct Element Method (DEM) was adopted as the main and preferred numerical technique because of its distinctive features and advantages. This method allows the phenomenon to be modelled and viewed microscopically at the inter-particle level by conceptualising the rock mass as an assembly of discrete particles interacting with each other via contacts. This method allows for a more detailed and dynamic monitoring of the hydraulic fracturing process. Sequel to a detailed review on the study of the hydraulic fracturing phenomenon, the research was extended to investigate specific cases of applications of hydraulic fracturing in geo-mechanical and environmental problems. Examples of such cases include carbon dioxide injection and storage in a reservoir system, and the behaviour of naturally occurring faults subjected to hydrostatic fluid pressures. The key factors governing the geo-mechanical responses of porous media (rocks), including reservoir formations were identified and further examined to ascertain the following: the role and inter-relationship between operating and material/fluid variables such as injection flow rate, fluid pressure, and interstitial velocity; type and pattern of fracture propagation; influence of environmental conditions as well as the configuration of the well-reservoir system, amongst others. Because of broad similarities in enabling conditions, analyses and applications of the phenomenon were also extended to study the sand production process. However, since the emphasis of the study was on identifying and examining the controlling variables as well as establishing patterns of sanding production rates rather than the study of the cavitation process, investigations were conducted using a finite element procedure; moreover, the limit of computational capacity has prevented a large scale DEM model for such problems. Modelling results show that fracturing mode, pattern and intensity are highly dependent on operating and environmental conditions; the reservoir erosion processes also indicate likewise tendencies. The numerical modelling techniques adopted and results obtained facilitate an improved understanding of geo-mechanical mechanisms at sub-surface systems, and could be further improved for industrial applications, such as site evaluation and assessment of the efficiency of stimulation techniques.