Download or read book Shear Related Reactivation of Fractures faults and the Effects on Permeability Evolution and Induced Seismicity written by Jiayi Yu and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-scale subsurface fluid injection is commonly deployed in geoengineering activities for hydraulic fracturing, enhanced geothermal system (EGS) development, carbon capture and storage (CCS) and underground waste disposal. Preexisting fractures or faults that are favorably orientated to in-situ stresses can be potentially shear-reactivated by the induced fluid overpressure. This is of particular interest in hydraulic fracturing-induced permeability enhancement in shale reservoirs where the presence of intricate natural fracture networks and their interaction with driven hydraulic fractures serve as pathways for the efficient transport of hydrocarbons. Conversely, fault and fracture reactivation in shear may also result in undesired triggered seismicity. The observation that induced seismicity can be of substantial magnitude and hence high hazard necessitates careful management to mitigate any associated risks. The following reports experimental observations that explore the role of shear-related reactivation of fractures and faults, inclusive of both bare surfaces and filled with proppant, and their impacts on the evolution of permeability (Chapters 1 and 2) and induced seismicity (Chapter 3). These activities and outcomes are described in detail in the following. Chapter 1 investigates the factors that influence fluid transfer into massive hydraulic fractures through tightly constrained laboratory experiments, specifically due to the reactivation of oblique fractures and proppant penetration during long-term shale reservoir depletion. We find that the evolution of the propped fracture's friction-permeability relationship is mainly controlled by the rock's friction/rigidity, which is sensitive to normal stress and proppant loading concentration but less sensitive to shear displacement rate. Our experiments examine both shale and steel fractures as analogs for weak and strong fracture surfaces and were calibrated using granular mechanics models (DEM). We observe that propped strong fractures have a continuous permeability decay at a constant rate during shear deformation, while permeability of weak fractures declines rapidly during pre-steady-state-friction and more slowly after transitioning to steady-state-friction. We believe that weak fracture walls accommodate shear deformation through distributed deformation across the proppant pack's interior and sliding at the fracture-proppant interface, whereas strong rocks accommodate shear deformation mainly through distributed deformation within the proppant pack. Chapter 2 reveals the importance of shear deformation in conditioning the fluid transport characteristics of shale reservoirs, specifically due to the prevalent existence of natural fractures. We conduct laboratory experiments reproducing fracture slip on both propped and unpropped fractures in Marcellus shale to explore the role of shear deformation as a primary control on permeability evolution and its correlation with initial stress state, shear stress magnitude and loading rate, and proppant loading concentration. For tests on unpropped fractures, we incorporate the complexity in both form and response of natural fracture topography by using pristine natural fractures directly split along bedding planes. Under low shear stress, unpropped fracture is prohibited from slipping by strongly mated interlocking asperities. As we increase shear stress exceeding the frictional strength of the contact, it exhibits great conductivity enhancement upon fracture reactivation followed by immediate and continuous decay. If shear stress is loaded incrementally instead of instantaneously -- broadly representing different fracking fluid injection rate -- fracture conductivity response to shear deformation is considerably muted. Unpropped fracture behaviors are also found to be strongly related to fracture roughness and fidelity of the interlocking asperities, while less sensitive to background stress state (confining stress). For propped fractures, we use manually ground fractures to specifically focus on the proppant impacts. In contrast to unpropped fractures, conductivity enhancement upon shear reactivation only presents where proppant is placed as non-uniformly distributed monolayer, which can be attributed to the generation of interparticle highly permeable flow paths. Otherwise, conductivity decreases as a result of proppant embedment, crushing, and compaction, however the reduction is muted with thicker proppant pack. Chapter 3 reports the role of critical stress in quantifying the magnitude of fluid-injection triggered earthquakes. We directly constrain the impact of pre-existing critical stresses on the relation linking seismic moment to injection volume. We report shear reactivation experiments on laboratory faults triggered by fluid pressurization. Experiments are conducted under both zero-displacement and constant shear stress boundary conditions -- differentiating the role of stress relaxation during fault slip. Both are shown capable of linking event magnitude (M) with injected volume ([delta]V). Injection response defines two discrete and linear stages in M-[delta]V space linked by a discrete up-step. The first limb (stage) represents the elastic deformation of the fault, the vertical up-step its reactivation and the second limb the rupture response as incremented sliding. Faults loaded to different pre-stress identify and quantify the controlling role of pre-existing shear stress in conditioning event magnitude. Laboratory results are readily explained by a model that considers the pre-existing stress state in the rupture of a rigid fault with slip limited to the zone of pressurization. This cumulative moment is defined as M=c/(1-c) G[delta]V with c defining the proportion of the static stress drop already applied by tectonic stressing, alternatively viewed as the proximity to failure. The model and confirmatory laboratory observations explain the triggered earthquakes at EGS sites larger than expected based on previous models relative to injection volumes. The three chapters of this dissertation comprise a series of three papers currently in-submittal. By order of chapter appearance, these papers are: Yu, J., Eijsink, A., Marone, C., Rivière, J., Shokouhi, P., Elsworth, D (2023) "Role of Critical Stress in Quantifying the Magnitude of Fluid-Injection Triggered Earthquakes" (In prep.) Yu, J., Wang, J., Li, Y., El-Fayoumi, A., Wu, R., Liu, X., Rijken, P., Rathbun, A., Elsworth, D. (2022) "Role of Shear Deformation on Shale Fracture Reactivation and Conductivity Evolution" (Manuscript submitted: Rock Mechanics and Rock Engineering) Yu, J., Wang, J., Li, Y., El-Fayoumi, A., Wu, R., Liu, X., Rijken, P., Rathbun, A., Elsworth, D. (2022) "Friction-Permeability Relationships for Propped Fractures in Shale" (Manuscript submitted: Rock Mechanics and Rock Engineering).

Download or read book Role of Fluid Pressure in Mechanics of Overthrust Faulting written by Marion King Hubbert and published by . This book was released on 1959 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Fluid Induced Seismicity written by Serge A. Shapiro and published by Cambridge University Press. This book was released on 2015-04-23 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The characterisation of fluid transport properties of rocks is one of the most important, yet difficult, challenges of reservoir geophysics, but is essential for optimal development of hydrocarbon and geothermal reservoirs. This book provides a quantitative introduction to the underlying physics, application, interpretation, and hazard aspects of fluid-induced seismicity with a particular focus on its spatio-temporal dynamics. It presents many real data examples of microseismic monitoring of hydraulic fracturing at hydrocarbon fields and of stimulations of enhanced geothermal systems. The author also covers introductory aspects of linear elasticity and poroelasticity theory, as well as elements of seismic rock physics and mechanics of earthquakes, enabling readers to develop a comprehensive understanding of the field. Fluid-Induced Seismicity is a valuable reference for researchers and graduate students working in the fields of geophysics, geology, geomechanics and petrophysics, and a practical guide for petroleum geoscientists and engineers working in the energy industry.

Download or read book Co Evolution of Fracture Permeability and Friction written by Elif Yildirim and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the following, we examine fracture permeabilityseismicity relationships in two separate studies. These combined studies separately elucidate (1) the role of preslip frictional healing, and (2) the combined effect of dynamic stressing and fluid-pressure-induced shear deformation on the evolution of fracture permeability and friction throughout the phases of the seismic cycle.Fracture permeability is a dynamic property under conditions of varying stress and responds to fluid overpressures applied during hydraulic stimulation. We use samples from the SIGMA-V site (Sanford Underground Research Facility (SURF), SD) to measure the co-evolution of fracture permeability and friction throughout phases of the seismic cycle. This is accomplished via slide-hold-slide and pore pressure stepping experiments completed in double direct shear. Fracture reactivation results in permeability enhancement only after sufficiently long interseismic repose periods. The magnitude of permeability increase from each reactivation, following the long hold periods, is critically dependent on the degree of fracture healing achieved in each pre-slip hold period. Shear dilation and permeability enhancement only results following a threshold repose period. Permeability enhances continuously with each pressure step with the highest permeability increase rate being with the first reactivation event. Our study establishes a direct linkage between fracture permeability and friction evolution throughout the seismic cycle and hydraulic shear, which applies across different fracture surface roughnesses.Mechanisms controlling fracture permeability enhancement during dynamic stressing remain unresolved. We probe these mechanisms through a series of fluid pressure pulse reactivations on saw-cut fractures in impermeable rock samples confined under in situ stresses. Each spiked pore fluid pressure pulse returns to the background control pore pressure while the evolution of fracture permeability and friction are continuously monitored. Peak magnitudes of the pore pressure pulses are successively incremented to both exclude and then include shear reactivation. Fracture permeability is shown to increase, both in the absence and then presence of reactivation by shear slip. Fracture permeability enhancement is permanent in the short-term despite the transient nature of the pressure pulses. The initiation of injection-induced slip significantly magnifies permeability increase over that due to changes in normal stress alone. The shear-induced permeability increase is apparent with a short delay after the first observed shear slip. Differentiation between the contribution of shear dilation and normal stress-only related processes, including unclogging and asperity damage and reseating, is apparent with a major slope change in permeability increase. Permeability increase scales with pore pressure amplitude and permeability increment scales with the amount of pre-stimulation sealing. This sealing and unsealing behavior is systematic and reversible. Enhanced permeability eventually returning to the pre-stimulated value over the long-term once the effective stress perturbations cease.

Download or read book Proceedings of GeoShanghai 2018 International Conference Multi physics Processes in Soil Mechanics and Advances in Geotechnical Testing written by Liangbo Hu and published by Springer. This book was released on 2018-05-03 with total page 547 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the second volume of the proceedings of the 4th GeoShanghai International Conference that was held on May 27 - 30, 2018. This conference showcased the recent advances and technology in geotechnical engineering, geoenvironmental engineering and transportation engineering. This volume, entitled “Multi-physics Processes in Soil Mechanics and Advances in Geotechnical Testing”, covers a wide range of topics in soil mechanics, focusing on the behaviours of partially saturated soils, combined effects of multi-physics processes in geological materials and systems, and emerging methods and techniques in geotechnical in-situ testing and monitoring. This book may benefit researchers and scientists from the academic fields of soil and rock mechanics, geotechnical engineering, geoenvironmental engineering, transportation engineering, geology, mining and energy, as well as practical engineers from the industry. Each of the papers included in this book received at least two positive peer reviews. The editors would like to express their sincerest appreciation to all of the anonymous reviewers all over the world, for their diligent work.

Download or read book Geologic Analysis of Naturally Fractured Reservoirs written by Ronald A. Nelson and published by Gulf Professional Publishing. This book was released on 1985 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reservoir Geomechanics written by Mark D. Zoback and published by Cambridge University Press. This book was released on 2010-04-01 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: This interdisciplinary book encompasses the fields of rock mechanics, structural geology and petroleum engineering to address a wide range of geomechanical problems that arise during the exploitation of oil and gas reservoirs. It considers key practical issues such as prediction of pore pressure, estimation of hydrocarbon column heights and fault seal potential, determination of optimally stable well trajectories, casing set points and mud weights, changes in reservoir performance during depletion, and production-induced faulting and subsidence. The book establishes the basic principles involved before introducing practical measurement and experimental techniques to improve recovery and reduce exploitation costs. It illustrates their successful application through case studies taken from oil and gas fields around the world. This book is a practical reference for geoscientists and engineers in the petroleum and geothermal industries, and for research scientists interested in stress measurements and their application to problems of faulting and fluid flow in the crust.

Download or read book Modeling of Fault Reactivation and Induced Seismicity During Hydraulic Fracturing of Shale gas Reservoirs written by and published by . This book was released on 2013 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have conducted numerical simulation studies to assess the potential for injection-induced fault reactivation and notable seismic events associated with shale-gas hydraulic fracturing operations. The modeling is generally tuned towards conditions usually encountered in the Marcellus shale play in the Northeastern US at an approximate depth of 1500 m (~;;4,500 feet). Our modeling simulations indicate that when faults are present, micro-seismic events are possible, the magnitude of which is somewhat larger than the one associated with micro-seismic events originating from regular hydraulic fracturing because of the larger surface area that is available for rupture. The results of our simulations indicated fault rupture lengths of about 10 to 20 m, which, in rare cases can extend to over 100 m, depending on the fault permeability, the in situ stress field, and the fault strength properties. In addition to a single event rupture length of 10 to 20 m, repeated events and aseismic slip amounted to a total rupture length of 50 m, along with a shear offset displacement of less than 0.01 m. This indicates that the possibility of hydraulically induced fractures at great depth (thousands of meters) causing activation of faults and creation of a new flow path that can reach shallow groundwater resources (or even the surface) is remote. The expected low permeability of faults in producible shale is clearly a limiting factor for the possible rupture length and seismic magnitude. In fact, for a fault that is initially nearly-impermeable, the only possibility of larger fault slip event would be opening by hydraulic fracturing; this would allow pressure to penetrate the matrix along the fault and to reduce the frictional strength over a sufficiently large fault surface patch. However, our simulation results show that if the fault is initially impermeable, hydraulic fracturing along the fault results in numerous small micro-seismic events along with the propagation, effectively preventing larger events from occurring. Nevertheless, care should be taken with continuous monitoring of induced seismicity during the entire injection process to detect any runaway fracturing along faults.

Download or read book Induced Seismicity Potential in Energy Technologies written by National Research Council and published by National Academies Press. This book was released on 2013-08-14 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past several years, some energy technologies that inject or extract fluid from the Earth, such as oil and gas development and geothermal energy development, have been found or suspected to cause seismic events, drawing heightened public attention. Although only a very small fraction of injection and extraction activities among the hundreds of thousands of energy development sites in the United States have induced seismicity at levels noticeable to the public, understanding the potential for inducing felt seismic events and for limiting their occurrence and impacts is desirable for state and federal agencies, industry, and the public at large. To better understand, limit, and respond to induced seismic events, work is needed to build robust prediction models, to assess potential hazards, and to help relevant agencies coordinate to address them. Induced Seismicity Potential in Energy Technologies identifies gaps in knowledge and research needed to advance the understanding of induced seismicity; identify gaps in induced seismic hazard assessment methodologies and the research to close those gaps; and assess options for steps toward best practices with regard to energy development and induced seismicity potential.

Download or read book Mechanics Structure and Evolution of Fault Zones written by Yehuda Ben-Zion and published by Springer Science & Business Media. This book was released on 2009-12-30 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considerable progress has been made recently in quantifying geometrical and physical properties of fault surfaces and adjacent fractured and granulated damage zones in active faulting environments. There has also been significant progress in developing rheologies and computational frameworks that can model the dynamics of fault zone processes. This volume provides state-of-the-art theoretical and observational results on the mechanics, structure and evolution of fault zones. Subjects discussed include damage rheologies, development of instabilities, fracture and friction, dynamic rupture experiments, and analyses of earthquake and fault zone data.

Download or read book Induced Microearthquakes and Seismicity Permeability Relationships in Fractures written by Yi Fang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Permeability evolves monotonically for smooth fractures but in a fluctuating pattern for highly roughened fractures. A higher roughness is likely to result in alternating compaction and dilation during shearing. Significant permeability damage may occur for rough samples when asperities are highly worn with wear products blocking fluid pathways. (4) There is no obvious correlation between permeability evolution and frictional behavior for rough fracture samples when fractures are subject to sudden sliding velocity change. Implications of our lab-scale experimental results suggest that characterization of fracture geometry would be beneficial for better understanding and managing induced seismicity and permeability development. In shale reservoir stimulation, fractures are propped to increase the permeability of the formation. On the other hand, the proppants may also influence the frictional strength of fractures. Thus, in the appendix, we explore the evolution of friction and permeability of a propped fracture using shearing-concurrent measurements of permeability during constant velocity shearing experiments. We observe that (1) the frictional response is mainly controlled by the normal stress and proppant thickness. High normal stress results in the crushing of proppant particles although this change in particle size distribution has almost no impact on the frictional response of the proppant-fracture system. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Moreover, under high normal stress, the reduced friction implies that shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from mono-layer to triple-layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming, suggesting that high proppant density during emplacement would help stabilize the fractures during injection. (2) Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Compared to the multi-layered specimen, the mono-layer case which has fewer displacement degrees-of-freedom exhibits the smallest initial permeability due to proppant embedment. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading. These combined conclusions suggest that the use of high-density proppants not only provides high hydraulic conductivity for hydrocarbon production but may also help to mitigate the risk of induced seismicity.

Download or read book Earthquake and Volcano Deformation written by Paul Segall and published by Princeton University Press. This book was released on 2010-01-04 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthquake and Volcano Deformation is the first textbook to present the mechanical models of earthquake and volcanic processes, emphasizing earth-surface deformations that can be compared with observations from Global Positioning System (GPS) receivers, Interferometric Radar (InSAR), and borehole strain- and tiltmeters. Paul Segall provides the physical and mathematical fundamentals for the models used to interpret deformation measurements near active faults and volcanic centers. Segall highlights analytical methods of continuum mechanics applied to problems of active crustal deformation. Topics include elastic dislocation theory in homogeneous and layered half-spaces, crack models of faults and planar intrusions, elastic fields due to pressurized spherical and ellipsoidal magma chambers, time-dependent deformation resulting from faulting in an elastic layer overlying a viscoelastic half-space and related earthquake cycle models, poroelastic effects due to faulting and magma chamber inflation in a fluid-saturated crust, and the effects of gravity on deformation. He also explains changes in the gravitational field due to faulting and magmatic intrusion, effects of irregular surface topography and earth curvature, and modern concepts in rate- and state-dependent fault friction. This textbook presents sample calculations and compares model predictions against field data from seismic and volcanic settings from around the world. Earthquake and Volcano Deformation requires working knowledge of stress and strain, and advanced calculus. It is appropriate for advanced undergraduates and graduate students in geophysics, geology, and engineering. Professors: A supplementary Instructor's Manual is available for this book. It is restricted to teachers using the text in courses. For information on how to obtain a copy, refer to: http://press.princeton.edu/class_use/solutions.html

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 Modern Shale Gas Development in the United States written by and published by . This book was released on 2009 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Seismic Monitoring of Induced Seismicity written by David W. Eaton and published by Cambridge University Press. This book was released on 2018-04-26 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to the principles and applications of passive seismic monitoring, providing an accessible overview of current research and technology.

Download or read book FRICTION AND PERMEABILITY EVOLUTION OF FRACUTRES AND FAULTS DURING STATIC REPOSE AND DYNAMIC REACTIVATION written by Kyungjae Im and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The co-evolution of fault/fracture friction and permeability represent important science/engineering challenges impacting natural and engineered systems. Friction directly controls the characteristics of natural fault slip, including inter-seismic healing, slow creep and earthquake rupture. Permeability evolution during fault slip and repose illuminates our understanding of perturbations to the earthquake-modulated natural hydraulic system and of subsurface engineering in recovering both shale gas and geothermal energy and in the safe subsurface sequestration of CO2. However, mechanisms controlling the evolution of friction and permeability during slow slip, fast rupture and inter-event repose are not clearly understood. For instance, the evolution of stick-slip amplitudes and recurrence, the role of inertia and its influence on frictional stability and the interdependence of these processes remain unclear. Furthermore, mechanisms of permeability evolution during the earthquake cycle (repose through rupture) are also poorly understood since they are influenced in a complex way by chemo-mechanical effects such as elastic/plastic compaction, shear comminution, mechanical dilation, pressure solution and stress corrosion. In this study, we explore fracture friction and permeability evolution during static and dynamic reactivation using both numerical and experimental approaches. This is described in the four chapters of this dissertation.