Study Of Natural And Hydraulic Fracture Interaction Using Semi Circular Bending Experiments
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Study Of Natural And Hydraulic Fracture Interaction Using Semi Circular Bending Experiments
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Author : Weiwei Wang
language : en
Publisher:
Release Date : 2014
Study Of Natural And Hydraulic Fracture Interaction Using Semi Circular Bending Experiments written by Weiwei Wang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Hydraulic fracturing is an indispensable technique for developing unconventional resources such as shale gas and tight oil. According to micro-seismic data, when hydraulic fractures interact with pre-existing natural fractures, the result can be a complex fracture network. While most simulation studies treat natural fractures as frictional interfaces with cohesion, core observations show that partially cemented and fully cemented natural fractures are widely present. We use semi-circular bending tests to examine propagation paths and strength of samples with pre-existing cemented fractures. In this study, synthetic Hydrostone samples with embedded inclusions of different mechanical properties are used to mimic cemented natural fractures. In a series of experiments, we assess the influence of the fracture approach angle, inclusion strength, and inclusion thickness on fracture propagation. Results show that fractures tend to cross inclusion with high approach angle and divert into the inclusion with low approach angle. The inclusion thickness does not change the crossing/diverting behavior for orthogonal approaching samples, but it changes the jog distance along the interface. Preliminary simulation results are used to explain the experimental observation. The assessments of fracture interaction in this study are in good agreement with previous work and theories.
The Effect Of Cemented Natural Fractures On Hydraulic Fracture Propagation
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Author : Weiwei Wang
language : en
Publisher:
Release Date : 2017
The Effect Of Cemented Natural Fractures On Hydraulic Fracture Propagation written by Weiwei Wang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
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.
Mechanics Of Hydraulic Fracturing
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Author : Xin-rong Zhang
language : en
Publisher: John Wiley & Sons
Release Date : 2023-01-05
Mechanics Of Hydraulic Fracturing written by Xin-rong Zhang and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-01-05 with Technology & Engineering categories.
Mechanics of Hydraulic Fracturing Comprehensive single-volume reference work providing an overview of experimental results and predictive methods for hydraulic fracture growth in rocks Mechanics of Hydraulic Fracturing: Experiment, Model, and Monitoring provides a summary of the research in mechanics of hydraulic fractures during the past two decades, plus new research trends to look for in the future. The book covers the contributions from theory, modeling, and experimentation, including the application of models to reservoir stimulation, mining preconditioning, and the formation of geological structures. The four expert editors emphasize the variety of diverse methods and tools in hydraulic fracturing and help the reader understand hydraulic fracture mechanics in complex geological situations. To aid in reader comprehension, practical examples of new approaches and methods are presented throughout the book. Key topics covered in the book include: Prediction of fracture shapes, sizes, and distributions in sedimentary basins, plus their importance in petroleum industry Real-time monitoring methods, such as micro-seismicity and trace tracking How to uncover geometries of fractures like dikes and veins Fracture growth of individual foundations and its applications Researchers and professionals working in the field of fluid-driven fracture growth will find immense value in this comprehensive reference on hydraulic fracturing mechanics.
Fracture Propagation In Naturally Fractured Reservoirs
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Author : Hunjoo Peter Lee
language : en
Publisher:
Release Date : 2015
Fracture Propagation In Naturally Fractured Reservoirs written by Hunjoo Peter Lee and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Investigations of hydrocarbons in tight formations require understanding of hydraulic fracturing in order to optimize the production and recovery of oil and natural gas. The classic description of hydraulic fracture is a single bi-wing planar feature, however, field observations show that hydraulic fracture growth in naturally fractured formations like shale is complex. Lack of knowledge concerning the remote stress impact and the interaction with planes of weakness on a fracture propagation trajectory leads to inaccurate predictions of the fracture geometry and the surface area required for the production estimation. Most studies in engineering mechanics extended the standard mixed-mode fracture propagation models, based on the near tip approximations, to include the impact of the tensile crack-parallel stress on the fracture propagation path. However, for fractures in the subsurface, the remote stress is compression, and internal fluid pressure or frictional stress become important in the near-tip stress field and the propagation trajectory. The Modified Maximum Tangential Principal Stress criterion (MMTPS-criterion) was introduced to address and evaluate the remote and internal crack stresses in the propagation path. The predictions of the fracture propagation angles by the MMTPS-criterion agreed with published experimental results of fractures propagating under both tensile and compressive external loads. In addition, the predictions matched well with uniaxial compression tests on hydrostone samples with the critical radial distance, defined by the process zone size, for open fractures that satisfy the Small Scale Yielding conditions. For short open fractures, a larger critical radial distance was required to correspond with the experimental results. The MMTPS-criterion was also capable of predicting lower propagation angles for closed cracks with higher friction coefficients. Preexisting discontinuities in shale, including natural fractures and bedding, act as planes of weakness that divert fracture propagation. To investigate the influences of weak planes on hydraulic fracture propagation, I performed Semi-Circular Bend (SCB) tests on Marcellus shale core samples containing calcite-filled natural fractures (veins). The approach angle of the induced fracture to the veins and the thickness of the veins had a strong influence on propagation. As the apprach angle became more oblique to the induced fracture plane, and as the vein got thicker, the induced fracture was more likely to divert into the vein. Microstructural analysis of tested samples showed that the induced fracture propagated in the middle of the vein rahter than the interface between vein and the rock matrix. Cleavage planes and fluid inclusion trails in the vein cements exerted some control on the fracture path. By combining the experimental results with theoretical fracture-mechanics arguments, the fracture toughness of the calcite veins was estimated to range from 0.99 MPa [square root of m] to 1.14 MPa [square root of m], depending on the value used for the Young's modulus of the calcite vein material. Measured fracture toughness of unfractured Marcellus shale was 0.64 MPa [square root of m]. A Discrete Element Method (DEM) based numerical modeling software, Particle Flow Code in three-dimensions (PFC3D), was utilized to reproduce and analyze the experimental results of Marcellus shale samples. The trend of numerical results correlated with the interaction feature of the experimental results for various approach angel and thickness (i.e., aperture) of the vein. Further sensitivity analysis on vein properties indicated that veins with lower stranght and higher stiffness contribute to more fracture diversion than veins with higher strenght and lower stiffness. Additionally, parallel bond breakages in the model show that microcracks were generated inside the vein before the induced fracture encountered the vein especially for the veins with higher stiffnesses when compared to the rock matrix. Most of the bond failure mode inside the vein and the induced fracture was tensile rather that shear mode.
Mechanics Of Hydraulic Fracturing
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Author : Ching H. Yew
language : en
Publisher: Gulf Professional Publishing
Release Date : 2014-09-25
Mechanics Of Hydraulic Fracturing written by Ching H. Yew and has been published by Gulf Professional Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-09-25 with Technology & Engineering categories.
Revised to include current components considered for today’s unconventional and multi-fracture grids, Mechanics of Hydraulic Fracturing, Second Edition explains one of the most important features for fracture design — the ability to predict the geometry and characteristics of the hydraulically induced fracture. With two-thirds of the world’s oil and natural gas reserves committed to unconventional resources, hydraulic fracturing is the best proven well stimulation method to extract these resources from their more remote and complex reservoirs. However, few hydraulic fracture models can properly simulate more complex fractures. Engineers and well designers must understand the underlying mechanics of how fractures are modeled in order to correctly predict and forecast a more advanced fracture network. Updated to accommodate today’s fracturing jobs, Mechanics of Hydraulic Fracturing, Second Edition enables the engineer to: Understand complex fracture networks to maximize completion strategies Recognize and compute stress shadow, which can drastically affect fracture network patterns Optimize completions by properly modeling and more accurately predicting for today’s hydraulic fracturing completions Discusses the underlying mechanics of creating a fracture from the wellbore Enhanced to include newer modeling components such as stress shadow and interaction of hydraulic fracture with a natural fracture, which aids in more complex fracture networks Updated experimental studies that apply to today’s unconventional fracturing cases
3 D Modeling Of Interaction Between A Hydraulic Fracture And Multiple Natural Fractures Using Finite Element Analysis
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Author : Debashish Talukder
language : en
Publisher:
Release Date : 2019
3 D Modeling Of Interaction Between A Hydraulic Fracture And Multiple Natural Fractures Using Finite Element Analysis written by Debashish Talukder and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Finite element method categories.
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.
Hydraulic Fracturing And Rock Mechanics
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Author : Yu Zhao
language : en
Publisher: Springer Nature
Release Date : 2023-06-21
Hydraulic Fracturing And Rock Mechanics written by Yu Zhao and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-06-21 with Science categories.
This open access book is the first to consider the effect of non-uniform fluid pressure in hydraulic fractures. The book covers the key topics in the process of hydraulic fracture nucleation, growth, interaction and fracture network formation. Laboratory experiments and theoretical modeling are combined to elucidate the formation mechanism of complex fracture networks. This book is suitable for master’s/Ph.D. students, scientists and engineers majoring in rock mechanics and petroleum engineering who need to use a more reliable model to predict fracture behavior.
Examining The Effect Of Cemented Natural Fractures On Hydraulic Fracture Propagation In Hydrostone Block Experiments
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Author : Benjamin Lee Bahorich
language : en
Publisher:
Release Date : 2012
Examining The Effect Of Cemented Natural Fractures On Hydraulic Fracture Propagation In Hydrostone Block Experiments written by Benjamin Lee Bahorich and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Micro seismic data and coring studies suggest that hydraulic fractures interact heavily with natural fractures creating complex fracture networks in naturally fractured reservoirs such as the Barnett shale, the Eagle Ford shale, and the Marcellus shale. However, since direct observations of subsurface hydraulic fracture geometries are incomplete or nonexistent, we look to properly scaled experimental research and computer modeling based on realistic assumptions to help us understand fracture intersection geometries. Most experimental analysis of this problem has focused on natural fractures with frictional interfaces. However, core observations from the Barnett and other shale plays suggest that natural fractures are largely cemented. To examine hydraulic fracture interactions with cemented natural fractures, we performed 9 hydraulic fracturing experiments in gypsum cement blocks that contained embedded planar glass, sandstone, and plaster discontinuities which acted as proxies for cemented natural fractures. There were three main fracture intersection geometries observed in our experimental program. 1) A hydraulic fracture is diverted into a different propagation path(s) along a natural fracture. 2) A taller hydraulic fracture bypasses a shorter natural fracture by propagating around it via height growth while also separating the weakly bonded interface between the natural fracture and the host rock. 3) A hydraulic fracture bypasses a natural fracture and also diverts down it to form separate fractures. The three main factors that seemed to have the strongest influence on fracture intersection geometry were the angle of intersection, the ratio of hydraulic fracture height to natural fracture height, and the differential stress. Our results show that bypass, separation of weakly bonded interfaces, diversion, and mixed mode propagation are likely in hydraulic fracture intersections with cemented natural fractures. The impact of this finding is that we need fully 3D computer models capable of accounting for bypass and mixed mode I-III fracture propagation in order to realistically simulate subsurface hydraulic fracture geometries.
Computational And Experimental Simulations In Engineering
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Author : Shaofan Li
language : en
Publisher: Springer Nature
Release Date : 2023-11-30
Computational And Experimental Simulations In Engineering written by Shaofan Li and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-11-30 with Technology & Engineering categories.
This book gathers the latest advances, innovations, and applications in the field of computational engineering, as presented by leading international researchers and engineers at the 29th International Conference on Computational & Experimental Engineering and Sciences (ICCES), held in Shenzhen, China on May 26-29, 2023. ICCES covers all aspects of applied sciences and engineering: theoretical, analytical, computational, and experimental studies and solutions of problems in the physical, chemical, biological, mechanical, electrical, and mathematical sciences. As such, the book discusses highly diverse topics, including composites; bioengineering & biomechanics; geotechnical engineering; offshore & arctic engineering; multi-scale & multi-physics fluid engineering; structural integrity & longevity; materials design & simulation; and computer modeling methods in engineering. The contributions, which were selected by means of a rigorous international peer-review process, highlight numerous exciting ideas that will spur novel research directions and foster multidisciplinary collaborations.
Experimental And Numerical Study Of Interaction Of A Pre Existing Natural Interface And An Induced Hydraulic Fracture
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Author : Mohammad Sarmadivaleh
language : en
Publisher:
Release Date : 2012
Experimental And Numerical Study Of Interaction Of A Pre Existing Natural Interface And An Induced Hydraulic Fracture written by Mohammad Sarmadivaleh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Today's huge growth of energy need may not be fulfilled except using new source of unconventional energy that should be stimulated hydraulically. However, these reservoirs are non-homogeneous and contain various types of interfaces which make their fracturing treatment difficult. In this study, the interaction between the hydraulic fracture and a natural interface were investigated using analytical, numerical and experimental approaches. This was done by doing sensitivity analysis on some of the important parameters.