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Numerical Investigation Of Interaction Between Hydraulic Fractures And Natural Fractures
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Book Synopsis Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures by : Wenxu Xue
Download or read book Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures written by Wenxu Xue and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing of a naturally-fractured reservoir is a challenge for industry, as fractures can have complex growth patterns when propagating in systems of natural fractures in the reservoir. Fracture propagation near a natural fracture (NF) considering interaction between a hydraulic fracture (HF) and a pre-existing NF, has been investigated comprehensively using a two dimensional Displacement Discontinuity Method (DDM) Model in this thesis. The rock is first considered as an elastic impermeable medium (with no leakoff), and then the effects of pore pressure change as a result of leakoff of fracturing fluid are considered. A uniform pressure fluid model and a Newtonian fluid flow model are used to calculate the fluid flow, fluid pressure and width distribution along the fracture. Joint elements are implemented to describe different NF contact modes (stick, slip, and open mode). The structural criterion is used for predicting the direction and mode of fracture propagation. The numerical model was used to first examine the mechanical response of the NF to predict potential reactivation of the NF and the resultant probable location for fracture re-initiation. Results demonstrate that: 1) Before the HF reaches a NF, the possibility of fracture re-initiation across the NF and with an offset is enhanced when the NF has weaker interfaces; 2) During the stage of fluid infiltration along the NF, a maximum tensile stress peak can be generated at the end of the opening zone along the NF ahead of the fluid front; 3) Poroelastic effects, arising from fluid diffusion into the rock deformation can induce closure and compressive stress at the center of the NF ahead of the HF tip before HF arrival. Upon coalescence when fluid flows along the NF, the poroelastic effects tend to reduce the value of the HF aperture and this decreases the tension peak and the possibility of fracture re-initiation with time. Next, HF trajectories near a NF were examined prior to coalesce with the NF using different joint, rock and fluid properties. Our analysis shows that: 1) Hydraulic fracture trajectories near a NF may bend and deviate from the direction of the maximum horizontal stress when using a joint model that includes initial joint deformation; 2) Hydraulic fractures propagating with higher injection rate or fracturing fluid of higher viscosity propagate longer distance when turning to the direction of maximum horizontal stress; 3) Fracture trajectories are less dependent on injection rate or fluid viscosity when using a joint model that includes initial joint deformation; whereas, they are more dominated by injection rate and fluid viscosity when using a joint model that excludes initial joint deformation.
Book Synopsis Extended Finite Element Method by : Amir R. Khoei
Download or read book Extended Finite Element Method written by Amir R. Khoei and published by John Wiley & Sons. This book was released on 2015-02-23 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces the theory and applications of the extended finite element method (XFEM) in the linear and nonlinear problems of continua, structures and geomechanics Explores the concept of partition of unity, various enrichment functions, and fundamentals of XFEM formulation. Covers numerous applications of XFEM including fracture mechanics, large deformation, plasticity, multiphase flow, hydraulic fracturing and contact problems Accompanied by a website hosting source code and examples
Book Synopsis Geomechanics and Hydraulic Fracturing for Shale Reservoirs by : Yu Wang
Download or read book Geomechanics and Hydraulic Fracturing for Shale Reservoirs written by Yu Wang and published by Scientific Research Publishing, Inc. USA. This book was released on 2020-07-01 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended as a reference book for advanced graduate students and research engineers in shale gas development or rock mechanical engineering. Globally, there is widespread interest in exploiting shale gas resources to meet rising energy demands, maintain energy security and stability in supply and reduce dependence on higher carbon sources of energy, namely coal and oil. However, extracting shale gas is a resource intensive process and is dependent on the geological and geomechanical characteristics of the source rocks, making the development of certain formations uneconomic using current technologies. Therefore, evaluation of the physical and mechanical properties of shale, together with technological advancements, is critical in verifying the economic viability of such formation. Accurate geomechanical information about the rock and its variation through the shale is important since stresses along the wellbore can control fracture initiation and frac development. In addition, hydraulic fracturing has been widely employed to enhance the production of oil and gas from underground reservoirs. Hydraulic fracturing is a complex operation in which the fluid is pumped at a high pressure into a selected section of the wellbore. The interaction between the hydraulic fractures and natural fractures is the key to fracturing effectiveness prediction and high gas development. The development and growth of a hydraulic fracture through the natural fracture systems of shale is probably more complex than can be described here, but may be somewhat predictable if the fracture system and the development of stresses can be explained. As a result, comprehensive shale geomechanical experiments, physical modeling experiment and numerical investigations should be conducted to reveal the fracturing mechanical behaviors of shale.
Book Synopsis Analysis of Interaction Between Hydraulic and Natural Fractures by : Jaber Taheri-Shakib
Download or read book Analysis of Interaction Between Hydraulic and Natural Fractures written by Jaber Taheri-Shakib and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of natural fractures at the hydraulic fracturing (HF) treatment is one of the most important considerations in increasing the production from this kind of reservoirs. Therefore, considering the interaction between the natural fractures and hydraulic fractures can have great impact on the analysis and design of fracturing process. Due to the existence of such natural fractures, the perturbation stress regime around the tip of hydraulic fracture leads to some deviation in the propagation of path of hydraulic fracture. Increasing the ratio of transverse stress to the interaction stress results in a reduction in the deviation of hydraulic fracturing propagation trajectory in the vicinity of natural fracture. In this study, we modeled a hydraulic fracture with the extended finite element method (XFEM) using a cohesive-zone technique. The XFEM is used to discrete the equations, allowing for the simulation of induced fracture propagation; no re-meshing of domain is required to model the interaction between hydraulic and natural fractures. XFEM results reveal that the distance and angle of natural fracture with respect to the hydraulic fracture have a direct impact on the magnitude of tensile and shear debonding. The possibility of intersection of natural fracture by the hydraulic fracture will increase with increasing the deviation angle value. At the approaching stage of hydraulic fracture to the natural fracture, hydraulic fracture tip exerts remote compressional and tensile stress on the interface of the natural fracture, which leads to the activation and separation of natural fracture walls.
Book Synopsis The Effect of Cemented Natural Fractures on Hydraulic Fracture Propagation by : Weiwei Wang
Download or read book The Effect of Cemented Natural Fractures on Hydraulic Fracture Propagation written by Weiwei Wang and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microseismic events, which are generated during hydraulic fracturing treatments, suggest that a complicated fracture network develops in many naturally−fractured unconventional reservoirs. Deformation along weak planes, such as cemented natural fractures, has been proposed as one of the possible reasons for fracture network complexity. Cemented natural fractures widely exist in shale reservoirs. They are diverse in composition and size, depending on the burial condition, the composition of the rock matrix, and the geochemical environment. The interaction between cemented natural fractures with hydraulic fractures generated as part of the reservoir stimulation are thought to impact hydraulic fracture propagation. Previous studies mostly treated natural fractures as frictional interfaces without considering the actual cement fillings. In this study, I analyzed the effect of cemented natural fractures on hydraulic fracture propagation by considering natural fracture thickness, mechanical properties and rock−cement interface bond strength. Firstly, I conducted a series of semi−circular bend (SCB) tests and corresponding numerical simulations to study the interaction between hydraulic and natural fractures. The SCB tests are attractive in general because of their simple setup with consistent results. The experimental results also served as a validation for numerical model. Two drawbacks of the SCB tests include that the test is unconfined and there is no fluid component. Numerical modeling can then be applied to extend results beyond these shortcomings. Synthetic hydrostone samples with embedded inclusions of different mechanical properties were used to mimic rock with cemented natural fractures. Experimental results identified several parameters that could be used to explain hydraulic fractures interaction with cemented natural fractures. The SCB test conditions that promoted fracture crossing were near−orthogonal approach angles, small natural fracture thicknesses, and strong rock−cement interfaces. Such conditions in a reservoir would promote long hydraulic fractures and less complicated fracture networks. In contrast, the SCB test conditions that caused fracture diverting were more oblique approach angles, large natural fracture thicknesses, and weak rock−cement interfaces, resulting in short hydraulic fractures and more complicated fracture networks. The SCB tests using synthetic rock samples provided insights into the hydraulic fracture propagation in naturally−fractured reservoirs. Through the numerical modeling with the finite element code in Abaqus, the impact of fluid driven fracturing on fracture−fracture interaction was investigated. Fracture propagation in two dimensions was modeled using the cohesive elements and anisotropic compressive remote stress conditions. Results suggest that if the natural fracture thickness is considered, the commonly used fracture crossing/diverting criterion will overestimate the hydraulic fracture crossing scenario. Factors including modulus contrast and coefficient of friction also influence hydraulic fracture interaction with natural fractures. An application of this work is the case of how bedding−parallel veins will affect hydraulic fracture height growth. Such natural fractures are abundant in the unconventional resource play in the Vaca Muerta formation in Argentina. When the rock−cement coefficient of friction is around 0.4−0.5, which most likely represents shale reservoirs, hydraulic fracture crossing behavior is affected by the modulus contrast between natural fractures and host rock as well as the natural fracture thickness.
Book Synopsis Hydraulic Fracture Modeling by : Yu-Shu Wu
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
Book Synopsis 3-D Modeling of Interaction Between a Hydraulic Fracture and Multiple Natural Fractures Using Finite Element Analysis by : Debashish Talukder
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.
Book Synopsis Numerical Simulation in Hydraulic Fracturing: Multiphysics Theory and Applications by : Xinpu Shen
Download or read book Numerical Simulation in Hydraulic Fracturing: Multiphysics Theory and Applications written by Xinpu Shen and published by CRC Press. This book was released on 2017-03-27 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: The expansion of unconventional petroleum resources in the recent decade and the rapid development of computational technology have provided the opportunity to develop and apply 3D numerical modeling technology to simulate the hydraulic fracturing of shale and tight sand formations. This book presents 3D numerical modeling technologies for hydraulic fracturing developed in recent years, and introduces solutions to various 3D geomechanical problems related to hydraulic fracturing. In the solution processes of the case studies included in the book, fully coupled multi-physics modeling has been adopted, along with innovative computational techniques, such as submodeling. In practice, hydraulic fracturing is an essential project component in shale gas/oil development and tight sand oil, and provides an essential measure in the process of drilling cuttings reinjection (CRI). It is also an essential measure for widened mud weight window (MWW) when drilling through naturally fractured formations; the process of hydraulic plugging is a typical application of hydraulic fracturing. 3D modeling and numerical analysis of hydraulic fracturing is essential for the successful development of tight oil/gas formations: it provides accurate solutions for optimized stage intervals in a multistage fracking job. It also provides optimized well-spacing for the design of zipper-frac wells. Numerical estimation of casing integrity under stimulation injection in the hydraulic fracturing process is one of major concerns in the successful development of unconventional resources. This topic is also investigated numerically in this book. Numerical solutions to several other typical geomechanics problems related to hydraulic fracturing, such as fluid migration caused by fault reactivation and seismic activities, are also presented. This book can be used as a reference textbook to petroleum, geotechnical and geothermal engineers, to senior undergraduate, graduate and postgraduate students, and to geologists, hydrogeologists, geophysicists and applied mathematicians working in this field. This book is also a synthetic compendium of both the fundamentals and some of the most advanced aspects of hydraulic fracturing technology.
Book Synopsis Imaging the Mechanics of Hydraulic Fracturing in Naturally-fractured Reservoirs Using Induced Seismicity and Numerical Modeling by : Xueping Zhao
Download or read book Imaging the Mechanics of Hydraulic Fracturing in Naturally-fractured Reservoirs Using Induced Seismicity and Numerical Modeling written by Xueping Zhao and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Simulation of Hydraulic Fractures and Their Interactions with Natural Fractures by : Varahanaresh Sesetty
Download or read book Simulation of Hydraulic Fractures and Their Interactions with Natural Fractures written by Varahanaresh Sesetty and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling the stimulated reservoir volume during hydraulic fracturing is important to geothermal and petroleum reservoir stimulation. The interaction between a hydraulic fracture and pre-existing natural fractures exerts significant control on stimulated volume and fracture network complexity. This thesis presents a boundary element and finite difference based method for modeling this interaction during hydraulic fracturing process. In addition, an improved boundary element model is developed to more accurately calculate the total stimulated reservoir volume. The improved boundary element model incorporates a patch to calculate the tangential stresses on fracture walls accurately, and includes a special crack tip element at the fracture end to capture the correct stress singularity the tips The fracture propagation model couples fluid flow to fracture deformation, and accounts for fracture propagation including the transition of a mechanically-closed natural fractures to a hydraulic fracture. The numerical model is used to analyze a number of stimulation scenarios and to study the resulting hydraulic fracture trajectory, fracture aperture, and pressures as a function of injection time. The injection pressure, fracture aperture profiles shows the complexity of the propagation process and its impact on stimulation design and proppant placement. The injection pressure is observed to decrease initially as hydraulic fracture propagates and then it either increases or decreases depending on the factors such as distance between hydraulic fracture and natural fracture, viscosity of the injected fluid, injection rate and also other factor that are discussed in detail in below sections. Also, the influence of flaws on natural fracture in its opening is modeled. Results shows flaws that are very small in length will not propagate but are influencing the opening of natural fracture. If the flaw is located near to one end tip the other end tip will likely propagate first and vice versa. This behavior is observed due to the stress shadowing effect of flaw on the natural fracture. In addition, sequential and simultaneous injection and propagation of multiple fractures is modeled. Results show that for sequential injection, the pressure needed to initiate the later fractures increases but the geometry of the fractures is less complicated than that obtained from simultaneous injection under the same fracture spacing and injection. It is also observed that when mechanical interaction is present, the fractures in sequential fracturing have a higher width reduction as the later fractures are formed.
Book Synopsis Numerical Investigation of Water Loss Mechanisms During Hydraulic Fracturing Flow-back Operation in Tight Oil Reservoirs by : Mingyuan Wang
Download or read book Numerical Investigation of Water Loss Mechanisms During Hydraulic Fracturing Flow-back Operation in Tight Oil Reservoirs written by Mingyuan Wang and published by . This book was released on 2016 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-stage hydraulic fracturing is widely applied in tight reservoir exploitation. Production is enhanced significantly if hydraulic fractures can connect to regions with enhanced permeability due to the presence of micro (and induced) fractures. However, less than 50% of fracturing fluids are typically recovered. This study models the mechanisms of water loss and retention in fracture-matrix system. The effects of capillarity and geomechanics are systematically investigated, and the time scale of water imbibition under different reservoir conditions is tested. During the shut-in (soaking) and flow-back periods, the fracture conductivity decreases as effective stress increases due to imbibition. Previous works have addressed fracture closure during the production phase; however, the coupling of imbibition due to multiphase flow and stress-dependent fracture properties during shut-in is less understood. Numerical simulation results indicate the circumstances under which this phenomenon might be beneficial or detrimental to subsequent on tight oil production. A series of mechanistic simulation models consisting of both hydraulic fractures and stochastically distributed micro fractures are constructed to simulate fluid distribution during shut-in and flow-back. Three systems: matrix, hydraulic fracture and micro fractures are explicitly represented in the computational domain. Fluid loss and retention mechanisms are systematically investigated in this study by subjecting mechanistic model to different reservoir conditions. Water imbibition into the matrix would help to displace hydrocarbons into nearby micro and hydraulic fractures, and this process could lead to an increase in initial rate. Although other water loss mechanisms including water loss in desiccated matrix and water trapping in induced micro fractures were proposed in literature, detailed understanding of the roles of water trapping in these systems is still lacking. Impacts of secondary fracture distributions and properties, matrix permeability, multiphase flow functions, wettability, initial saturation, water injection rate and shut-in duration on fluid retention and the associated time scales are assessed. Increase in short-term oil production as a result of imbibition could be counteracted by the reduction in flow capability due to fracture closure. Therefore, the coupling of stress-dependent fracture conductivity and imbibition are studied next. Our results indicate that fracture compaction can enhance imbibition and water loss, which in turn leads to further reduction in fracture pressure and conductivity. Spatial variability in micro-fracture properties is also modeled probabilistically to investigate whether it is possible for fracturing fluid to be trapped in the micro fractures, or conversely, the micro fractures could provide alternate pathways for fluids to access the hydraulic fracture systems. This work presents a quantitative study of the controlling factors of water retention due to fluid-rock properties and geomechanics. It investigates the roles of multi-scale fractures in flow-back behavior and ensuing recovery performance. The results highlight 1) the crucial interplay between shut-in duration and properties of connected fractures in short- and long-term production performances; 2) the critical interaction between imbibition and geomechanics in short- and long-term production performances. The results would have considerable impacts on understanding and improving current industry practice on fracturing design and assessment of stimulated reservoir volume.
Book Synopsis Unconventional Reservoir Geomechanics by : Mark D. Zoback
Download or read book Unconventional Reservoir Geomechanics written by Mark D. Zoback and published by Cambridge University Press. This book was released on 2019-05-16 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the key geologic, geomechanical and engineering principles that govern the development of unconventional oil and gas reservoirs. Covering hydrocarbon-bearing formations, horizontal drilling, reservoir seismology and environmental impacts, this is an invaluable resource for geologists, geophysicists and reservoir engineers.
Book Synopsis Hydraulic Fracture Mechanics by : Peter Valkó
Download or read book Hydraulic Fracture Mechanics written by Peter Valkó and published by . This book was released on 1995 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book explores the theoretical background of one of the most widespread activities in hydrocarbon wells, that of hydraulic fracturing. A comprehensive treatment of the basic phenomena includes: linear elasticity, stresses, fracture geometry and rheology. The diverse concepts of mechanics are integrated into a coherent description of hydraulic fracture propagation. The chapters in the book are cross-referenced throughout and the connections between the various phenomena are emphasized. The book offers readers a unique approach to the subject with the use of many numerical examples.
Book Synopsis Modelling Rock Fracturing Processes by : Baotang Shen
Download or read book Modelling Rock Fracturing Processes written by Baotang Shen and published by Springer Nature. This book was released on 2020-05-06 with total page 579 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the second edition of the well-known textbook Modelling Rock Fracturing Processes. The new and extended edition provides the theoretical background of rock fracture mechanics used for modelling of 2-D and 3-D geomechanics problems and processes. Fundamentals of rock fracture mechanics integrated with experimental studies of rock fracturing processes are highlighted. The computer programs FRACOD 2D and 3D are used to analyse fracture initiation and propagation for the three fracture modes: Mode I, II and III. Coupled fracture modelling with other continuous and distinct element codes including FLAC, PFC, RFPA, TOUGH are also described. A series of applications of fracture modelling with importance for modern society is presented and discussed by distinguished rock fracture modelling experts.
Book Synopsis Hydraulic Fracture Propagation Through Geological Discontinuities by : Ella María Llanos Rodríguez
Download or read book Hydraulic Fracture Propagation Through Geological Discontinuities written by Ella María Llanos Rodríguez and published by . This book was released on 2015 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing is a stimulation technique widely used to enhance hydrocarbon production and geothermal energy extraction. Other applications include waste disposal and cave inducement and preconditioning of ore for mining. Rocks are naturally fractured and therefore the little-understood problem of hydraulic fracture growth through these pre-existing discontinuities is a key area of research. Mathematical criteria for predicting whether an induced fracture will cross a discontinuity have been published by several authors. Some used parameters that are difficult to quantify, neglected the stress induced by the hydraulic fracture itself and ignored fluid viscosity effects on crossing behaviour. Others ignored the presence of fluid in the hydraulic fracture, the possibility of fracture re-initiation after slippage and the effect of surface features on crossing. Numerical studies have shown that viscosity-dominated hydraulic fractures would induce slip on the discontinuity more easily than toughness-dominated hydraulic fractures. This implies that crossing should be more difficult for viscosity-dominated hydraulic fractures. To investigate the interaction between hydraulic and natural fractures, laboratory experiments are combined with numerical and analytical work in this thesis to extend two previously published criteria. This thesis shows the effect of viscosity on the crossing interaction is complex and cannot be predicted based only on whether slip occurs on the discontinuity before the hydraulic fracture intersects it. The laboratory work can also be applied to improved understanding of the effect of the stress field on crossing as it relates to hydraulic fracture height growth. Prediction of the effect of weak bedding planes on height growth has recently gained importance as the risk of vertical growth of fractures into aquifers has emerged as a concern in shale gas and coal seam gas operations. The findings herein can be applied to this problem if the frictional interfaces are considered to represent weak bedding planes. Complete treatment of the height growth problem requires considering fracture growth through elastic layers with contrasts in physical properties. The experiments show hydraulic fractures may grow to become elliptical because they extend more quickly and further in the direction of maximum stress or in the direction with fewer discontinuities. The preparation of the samples underlined the effect of local imperfections on discontinuities. Small areas of higher or lower contact stress can aid or inhibit fracture initiation. Rock plates must be smooth and flat in order to control this parameter and obtain valid experimental comparisons for contact stress and the other parameters controlling crossing. Numerical and analytical results are presented as a mathematical expression with universal curves for the locations of slip starting points, providing an important aid for designing industrial hydraulic fractures. One difference between the approach used here and that used by others is their use of the fracture-tip singular stress solution, meaning they do not consider the effect of the non-singular stresses existing around a pressurised fracture. This thesis therefore improves their work. Experimental and theoretical outcomes herein suggest that hydraulic fracture growth through an orthogonal discontinuity does not depend primarily on the interface friction coefficient. This finding contradicts several models.
Book Synopsis Rock Fractures and Fluid Flow by : National Research Council
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.
Book Synopsis An Experimental and Numerical Investigation Into Hydraulic Fracture Propagation in Naturally Fractured Shale Gas Reservoirs by : Betul Yildirim
Download or read book An Experimental and Numerical Investigation Into Hydraulic Fracture Propagation in Naturally Fractured Shale Gas Reservoirs written by Betul Yildirim and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
