Download or read book Multiscale Analysis of Mechanical and Transport Properties in Shale Gas Reservoirs written by Mohammad Hatami and published by . This book was released on 2021 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on multiscale analysis in shale to improve understanding of mechanical and transport properties in shale gas reservoirs. Laboratory measurements of the effects of constant confining pressure (CCP), and constant effective stress (CES) on permeability were coupled with multiscale finite element simulations and the development of a comprehensive apparent permeability model to study the mechanical behavior of shale and transport mechanisms in shale. Predicting long-term production from gas shale reservoirs is a challenging task due to changes in effective stress and permeability during gas production. Unlike coal, the variation of sorbing gas permeability with pore pressure in shale does not always feature a biphasic trend under a constant confining pressure. The present contribution demonstrates that the biphasic dependence of permeability on pore pressure depends on a number of physical and geometrical factors, each with a distinct impact on gas permeability. This includes pore size, adsorption isotherm, and the variation of gas viscosity with pore pressure.

Download or read book Study of Multi scale Transport Phenomena in Tight Gas and Shale Gas Reservoir Systems written by Craig Matthew Freeman and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrocarbon resources found in shale reservoirs have become an important energy source in recent years. Unconventional geological and engineering features of shale systems pose challenges to the characterization of these systems. These challenges have impeded efficient economic development of shale resources. New fundamental insights and tools are needed to improve the state of shale gas development. Few attempts have been made to model the compositional behavior of fluids in shale gas reservoirs. The transport and storage of reservoir fluids in shale is controlled by multiple distinct micro-scale physical phenomena. These phenomena include preferential Knudsen diffusion, differential desorption, and capillary critical effects. Together, these phenomena cause significant changes in fluid composition in the subsurface and a measureable change in the composition of the produced gas over time. In order to quantify this compositional change we developed a numerical model describing the coupled processes of desorption, diffusion, and phase behavior in heterogeneous ultra-tight rocks as a function of pore size. The model captures the various configurations of fractures induced by shale gas fracture stimulation. Through modeling of the physics at the macro-scale (e.g. reservoir-scale hydraulic fractures) and micro-scale (e.g. Knudsen diffusion in kerogen nanopores), we illustrate how and why gas composition changes spatially and temporally during production. We compare the results of our numerical model against measured composition data obtained at regular intervals from shale gas wells. We utilize the characteristic behaviors explicated by the model results to identify features in the measured data. We present a basis for a new method of production data analysis incorporating gas composition measurements in order to develop a more complete diagnostic process. Distinct fluctuations in the flowing gas composition are shown to uniquely identify the onset of fracture interference in horizontal wells with multiple transverse hydraulic fractures. The timescale and durations of the transitional flow regimes in shales are quantified using these measured composition data. These assessments appear to be robust even for high levels of noise in the rate and pressure data. Integration of the compositional shift analysis of this work with modern production analysis is used to infer reservoir properties. This work extends the current understanding of flow behavior and well performance for shale gas systems to encompass the physical phenomena leading to compositional change. This new understanding may be used to aid well performance analysis, optimize fracture and completion design, and improve the accuracy of reserves estimates. In this work we contribute a numerical model which captures multicomponent desorption, diffusion, and phase behavior in ultra-tight rocks. We also describe a workflow for incorporating measured gas composition data into modern production analysis. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151782

Download or read book Transport in Shale Reservoirs written by Kun Sang Lee and published by Gulf Professional Publishing. This book was released on 2019-02-20 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport in Shale Reservoirs fills the need for a necessary, integrative approach on shale reservoirs. It delivers both the fundamental theories of transport in shale reservoirs and the most recent advancements in the recovery of shale oil and gas in one convenient reference. Shale reservoirs have distinctive features dissimilar to those of conventional reservoirs, thus an accurate evaluation on the behavior of shale gas reservoirs requires an integrated understanding on their characteristics and the transport of reservoir and fluids. Updates on the various transport mechanisms in shale, such as molecular diffusion and phase behavior in nano-pores Applies theory to practice through simulation in both shale oil and gas Presents an up-to-date reference on remaining challenges, such as organic material in the shale simulation and multicomponent transport in CO2 injection processes

Download or read book Integrative Understanding of Shale Gas Reservoirs written by Kun Sang Lee and published by Springer. This book was released on 2016-02-03 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely book begins with an overview of shale gas reservoir features such as natural fracture systems, multi-fractured horizontal wells, adsorption/desorption of methane, and non-linear flow within the reservoir. Geomechanical modelling, an aspect of importance in ultra-low permeability reservoirs, is also presented in detail. Taking these complex features of shale reservoirs into account, the authors develop a numerical model, which is verified with field data using the history matching technique. Based on this model, the pressure transient and production characteristics of a fractured horizontal well in a shale gas reservoir are analysed with respect to reservoir and fracture properties. Methods for the estimation of shale properties are also detailed. Minifrac tests, rate transient tests (RTA), and type curve matching are used to estimate the initial pressure, permeability, and fracture half-length. Lastly, future technologies such as the technique of injecting CO2 into shale reservoirs are presented. The book will be of interest to industrial practitioners, as well as to academics and graduate students in the field of reservoir engineering.

Download or read book Challenges in Modelling and Simulation of Shale Gas Reservoirs written by Jebraeel Gholinezhad and published by Springer. This book was released on 2017-12-27 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the problems involved in the modelling and simulation of shale gas reservoirs, and details recent advances in the field. It discusses various modelling and simulation challenges, such as the complexity of fracture networks, adsorption phenomena, non-Darcy flow, and natural fracture networks, presenting the latest findings in these areas. It also discusses the difficulties of developing shale gas models, and compares analytical modelling and numerical simulations of shale gas reservoirs with those of conventional reservoirs. Offering a comprehensive review of the state-of-the-art in developing shale gas models and simulators in the upstream oil industry, it allows readers to gain a better understanding of these reservoirs and encourages more systematic research on efficient exploitation of shale gas plays. It is a valuable resource for researchers interested in the modelling of unconventional reservoirs and graduate students studying reservoir engineering. It is also of interest to practising reservoir and production engineers.

Download or read book Flow and Transport Properties of Unconventional Reservoirs 2018 written by Jianchao Cai and published by MDPI. This book was released on 2019-07-23 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unconventional reservoirs are usually complex and highly heterogeneous, such as shale, coal, and tight sandstone reservoirs. The strong physical and chemical interactions between fluids and pore surfaces lead to the inapplicability of conventional approaches for characterizing fluid flow in these low-porosity and ultralow-permeability reservoir systems. Therefore, new theories and techniques are urgently needed to characterize petrophysical properties, fluid transport, and their relationships at multiple scales for improving production efficiency from unconventional reservoirs. This book presents fundamental innovations gathered from 21 recent works on novel applications of new techniques and theories in unconventional reservoirs, covering the fields of petrophysical characterization, hydraulic fracturing, fluid transport physics, enhanced oil recovery, and geothermal energy. Clearly, the research covered in this book is helpful to understand and master the latest techniques and theories for unconventional reservoirs, which have important practical significance for the economic and effective development of unconventional oil and gas resources.

Download or read book Fundamentals of Gas Shale Reservoirs written by Reza Rezaee and published by John Wiley & Sons. This book was released on 2015-07-01 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides comprehensive information about the key exploration, development and optimization concepts required for gas shale reservoirs Includes statistics about gas shale resources and countries that have shale gas potential Addresses the challenges that oil and gas industries may confront for gas shale reservoir exploration and development Introduces petrophysical analysis, rock physics, geomechanics and passive seismic methods for gas shale plays Details shale gas environmental issues and challenges, economic consideration for gas shale reservoirs Includes case studies of major producing gas shale formations

Download or read book Fine Scale Characterization of Shale Reservoirs written by Mehdi Ostadhassan and published by Springer. This book was released on 2018-03-24 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the authors' extensive experience and interdisciplinary approach to demonstrate how acquiring and integrating data using a variety of analytical equipment can provide better insights into unconventional shale reservoir rocks and their constituent components. It focuses on a wide range of properties of unconventional shale reservoirs, discussing the use of conventional and new analytical methods for detailed measurements of mechanical properties of both organic and inorganic constituent elements as well as of the geochemical characteristics of organic components and their origins. It also addresses the investigation of porosity, pore size and type from several perspectives to help us to define unconventional shale formation. All of these analyses are treated individually, but brought together to present the rock sample on a macro scale. This book is of interest to researchers and graduate students from various disciplines, such as petroleum, civil, and mechanical engineering, as well as from geoscience, geology, geochemistry and geophysics. The methods and approaches can be further extended to biology and medicine.

Download or read book Petrophysics written by Djebbar Tiab and published by Elsevier. This book was released on 2024-03-29 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: Petrophysics, a seminal text in the field authored by recognized experts, now in its 5th edition, delivers information for reservoir engineers, production engineers and geoscience students fundamental to understanding rock-fluid interaction, and critical to maximizing reservoir performance while minimizing emissions and environmental impacts. This new edition lays a foundation through an introduction to petroleum geology, including an overview of pre- and post- carbon emission concerns, porosity and permeability, formation resistivity and water saturation, capillary pressure, wettability, applications of Darcy’s Law, naturally fractured reservoirs, stress effects on reservoir rock, reservoir characterization and well logs, fluid-rock interactions, shale gas and shale oil in unconventional reservoirs, and culminates in current studies on permeability from practical interpretation of pressure and rate transient analysis of tight and shale reservoirs. Each chapter synthesizes relevant theory, studies and advances, methods, procedures, calculations, definitions, exercises and assignments designed to reinforce learning. • Continues its longstanding, 28-year history as the leading book on petrophysics • Captures advances in field technologies, reservoir evaluation and testing, porosity, permeability, updated calculations and indices in wettability, permeability, brittleness and fracability. • Includes up-to-date discussions on carbon footprints and strategies to reduce emissions • Each chapter synthesizes relevant theory, studies and advances, methods, procedures, calculations, definitions, exercises and assignments designed to reinforce learning

Download or read book Geomechanical Studies of the Barnett Shale Texas USA written by John Peter Vermylen and published by Stanford University. This book was released on 2011 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents five studies of a gas shale reservoir using diverse methodologies to investigate geomechanical and transport properties that are important across the full reservoir lifecycle. Using the Barnett shale as a case study, we investigated adsorption, permeability, geomechanics, microseismicity, and stress evolution in two different study areas. The main goals of this thesis can be divided into two parts: first, to investigate how flow properties evolve with changes in stress and gas species, and second, to understand how the interactions between stress, fractures, and microseismicity control the creation of a permeable reservoir volume during hydraulic fracturing. In Chapter 2, we present results from adsorption and permeability experiments conducted on Barnett shale rock samples. We found Langmuir-type adsorption of CH4 and N2 at magnitudes consistent with previous studies of the Barnett shale. Three of our samples demonstrated BET-type adsorption of CO2, in contrast to all previous studies on CO2 adsorption in gas shales, which found Langmuir-adsorption. At low pressures (600 psi), we found preferential adsorption of CO2 over CH4 ranging from 3.6x to 5.5x. While our measurements were conducted at low pressures (up to 1500 psi), when our model fits are extrapolated to reservoir pressures they reach similar adsorption magnitudes as have been found in previous studies. At these high reservoir pressures, the very large preferential adsorption of CO2 over CH4 (up to 5-10x) suggests a significant potential for CO2 storage in gas shales like the Barnett if practical problems of injectivity and matrix transport can be overcome. We successfully measured permeability versus effective stress on two intact Barnett shale samples. We measured permeability effective stress coefficients less than 1 on both samples, invalidating our hypothesis that there might be throughgoing flow paths within the soft, porous organic kerogen that would lead the permeability effective stress coefficient to be greater than 1. The results suggest that microcracks are likely the dominant flow paths at these scales. In Chapter 3, we present integrated geological, geophysical, and geomechanical data in order to characterize the rock properties in our Barnett shale study area and to model the stress state in the reservoir before hydraulic fracturing occurred. Five parallel, horizontal wells were drilled in the study area and then fractured using three different techniques. We used the well logs from a vertical pilot well and a horizontal well to constrain the stress state in the reservoir. While there was some variation along the length of the well, we were able to determine a best fit stress state of Pp = 0.48 psi/ft, Sv = 1.1 psi/ft, SHmax = 0.73 psi/ft, and Shmin = 0.68 psi/ft. Applying this stress state to the mapped natural fractures indicates that there is significant potential for induced shear slip on natural fracture planes in this region of the Barnett, particularly close to the main hydraulic fracture where the pore pressure increase during hydraulic fracturing is likely to be very high. In Chapter 4, we present new techniques to quantify the robustness of hydraulic fracturing in gas shale reservoirs. The case study we analyzed involves five parallel horizontal wells in the Barnett shale with 51 frac stages. To investigate the numbers, sizes, and types of microearthquakes initiated during each frac stage, we created Gutenberg-Richter-type magnitude distribution plots to see if the size of events follows the characteristic scaling relationship found in natural earthquakes. We found that slickwater fracturing does generate a log-linear distribution of microearthquakes, but that it creates proportionally more small events than natural earthquake sources. Finding considerable variability in the generation of microearthquakes, we used the magnitude analysis as a proxy for the "robustness" of the stimulation of a given stage. We found that the conventionally fractured well and the two alternately fractured wells ("zipperfracs") were more effective than the simultaneously fractured wells ("simulfracs") in generating microearthquakes. We also found that the later stages of fracturing a given well were more successful in generating microearthquakes than the early stages. In Chapter 5, we present estimates of stress evolution in our study reservoir through analysis of the instantaneous shut-in pressure (ISIP) at the end of each stage. The ISIP increased stage by stage for all wells, but the simulfrac wells showed the greatest increase and the zipperfrac wells the least. We modeled the stress increase in the reservoir with a simple sequence of 2-D cracks along the length of the well. When using a spacing of one crack per stage, the modeled stress increase was nearly identical to the measured stress increase in the zipperfrac wells. When using three cracks per stage, the modeled final stage stress magnitude matched the measured final stage stress magnitude from the simulfrac wells, but the rate of stress increase in the simulfrac wells was much more gradual than the model predicted. To further investigate the causes of these ISIP trends, we began numerical flow and stress analysis to more realistically model the processes in the reservoir. One of our hypotheses was that the shorter total time needed to complete all the stages of the simulfrac wells was the cause of the greater ISIP increase compared to the zipperfrac wells. The microseismic activity level measured in Chapter 4 also correlates with total length of injection, suggesting leak off into the reservoir encouraged shear failure. Numerical modeling using the coupled FEM and flow software GEOSIM was able to model some cumulative stress increase the reservoir, but the full trend was not replicated. Further work to model field observations of hydraulic fracturing will enhance our understanding of the impact that hydraulic fracturing and stress change have on fracture creation and permeability enhancement in gas shales.

Download or read book Characterization of an Upper Permian Tight Gas Reservoir written by Philipp Antrett and published by Springer Science & Business Media. This book was released on 2013-03-22 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The thesis of Philipp Antrett is focused on reservoir properties, petrography, lithofacies and sedimentology, core analysis and nanoporosity studies. It will be of major interest for colleagues involved in the exploration and production of tight gas reservoirs in Northern Europe and elsewhere." - François Roure, August 2012 This thesis describes a multidisciplinary, multiscale approach to the analysis of tight gas reservoirs. It focused initially on the facies architecture of a Permian tight gas field in the Southern Permian Basin (SPB), East Frisia, northern Germany. To improve field development, 3D seismic data, wireline and core data were compared to a reservoir analogue in the Panamint Valley, California, United States. In addition to the large scale approach, a work flow that investigates microporosity by combining Scanning Electron Microscopy-Broad Ion Beam (SEM-BIB) and optical microscopy was developed. For a better understanding of the depositional environment and reservoir rock distribution in the SPB, a sedimentary facies analysis of four cores from the tight gas field in East Frisia was compared to a second study area in northern central Germany. This study demonstrates that tight gas exploration and production requires multidisciplinary, multiscale approaches beyond standard seismic interpretation work flows to better understand the temporal and spatial evolution of these complex reservoirs.

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.

Download or read book Petrophysical Characterization and Fluids Transport in Unconventional Reservoirs written by Jianchao Cai and published by Elsevier. This book was released on 2019-01-24 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Petrophysical Characterization and Fluids Transport in Unconventional Reservoirs presents a comprehensive look at these new methods and technologies for the petrophysical characterization of unconventional reservoirs, including recent theoretical advances and modeling on fluids transport in unconventional reservoirs. The book is a valuable tool for geoscientists and engineers working in academia and industry. Many novel technologies and approaches, including petrophysics, multi-scale modelling, rock reconstruction and upscaling approaches are discussed, along with the challenge of the development of unconventional reservoirs and the mechanism of multi-phase/multi-scale flow and transport in these structures. Includes both practical and theoretical research for the characterization of unconventional reservoirs Covers the basic approaches and mechanisms for enhanced recovery techniques in unconventional reservoirs Presents the latest research in the fluid transport processes in unconventional reservoirs

Download or read book Unconventional Shale Gas Development written by Rouzbeh G. Moghanloo and published by Gulf Professional Publishing. This book was released on 2022-02-23 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unconventional Shale Gas Development: Lessons Learned gives engineers the latest research developments and practical applications in today’s operations. Comprised of both academic and corporate contributors, a balanced critical review on technologies utilized are covered. Environmental topics are presented, including produced water management and sustainable operations in gas systems. Machine learning applications, well integrity and economic challenges are also covered to get the engineer up-to-speed. With its critical elements, case studies, history plot visuals and flow charts, the book delivers a critical reference to get today’s petroleum engineers updated on the latest research and applications surrounding shale gas systems. Bridges the gap between the latest research developments and practical applications through case studies and workflow charts Helps readers understand the latest developments from the balanced viewpoint of academic and corporate contributors Considers environmental and sustainable operations in shale gas systems, including produced water management

Download or read book Shale Oil and Gas Handbook written by Sohrab Zendehboudi and published by Gulf Professional Publishing. This book was released on 2016-11-19 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shale Oil and Gas Handbook: Theory, Technologies, and Challenges provides users with information on how shale oil and gas exploration has revolutionized today’s energy industry. As activity has boomed and job growth continues to increase, training in this area for new and experienced engineers is essential. This book provides comprehensive information on both the engineering design and research aspects of this emerging industry. Covering the full spectrum of basic definitions, characteristics, drilling techniques, and processing and extraction technologies, the book is a great starting point to educate oil and gas personnel on today’s shale industry. Critical topics covered include characterization of shale gas, theory and methods, typical costs, and obstacles for exploration and drilling, R&D and technology development in shale production, EOR methods in shale oil reservoirs, and the current status and impending challenges for shale oil and gas, including the inevitable future prospects relating to worldwide development. Reveals all the basic information needed to quickly understand today’s shale oil and gas industry, including advantages and disadvantages, equipment and costs, flow diagrams, and processing stages Evenly distributes coverage between oil and gas into two parts, as well as upstream and downstream content Provides a practical handbook with real-world case studies and problem examples, including formulas and calculations

Download or read book Mechanical Properties of Shale Gas Reservoir Rocks and Its Relation to the In situ Stress Variation Observed in Shale Gas Reservoirs written by Hiroki Sone and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main focus of this thesis is to study the basic rock mechanical properties of shale gas reservoir rocks, the in-situ state of stress in shale gas reservoirs, and their inter-relation. Laboratory studies on the elastic and deformational mechanical properties of gas shales show that these rocks exhibit wide range of mechanical properties and significant anisotropy reflecting their wide range of material composition and fabric anisotropy. The elastic properties of these shale rocks are successfully described by tracking the relative amount soft components (clay and solid organic materials) in the rock and also acknowledging the anisotropic distribution of the soft components. Gas shales were also found to possess relatively stronger degree of anisotropy compared to other organic-rich shales studied in the literature, possibly due to the fact that these rocks come from peak-maturity source rocks. The deformational properties studied by observing the ductile creep behavior and brittle strengths were also found to be influenced by the amount of soft components in the rock and exhibited mechanical anisotropy. A strong correlation between the elastic properties and the deformational properties was also found through comparison of laboratory data. The relation between the elastic modulus and magnitude of ductile creep is investigated through differential effective medium (DEM) modeling of the shale elastic properties. The partitioning of the far-field stress between the stiff and soft components was calculated in the DEM modeling to forward model the ductile creep behavior of the shales. Results showed that the correlation between the elastic properties and magnitude of ductile creep arises because they are both influenced by the stress partitioning in the rocks. Examination of a FMI image log from a vertical well in Barnett shale showed that the in-situ state of stress fluctuates rapidly within the reservoir in terms of the orientation and magnitude of the principal stress. The appearance and disappearance of drilling-induced tensile fractures roughly correlated with the variation in the clay and organic content in the formation, suggesting that there is a fluctuation in the magnitude of the horizontal stress difference, on the order of 10 MPa, that may be controlled by the mechanical heterogeneity of the formations. In order to explain the linkage between the observed stress variation and formation heterogeneity, we focused on the variation of ductile creep behavior exhibited by the gas shale rocks observed in the laboratory. The laboratory creep data was analyzed under the framework of viscoelastic theory to quantify its behavior and allow the calculation of the stress carrying capacity of the rocks. The viscoelastic behavior of the gas shales were found to be best approximated by a power-law function of time and the accumulation of differential stress over geological time in these rocks were calculated according to this constitutive description. Stress analysis assuming a simple constant strain rate tectonic loading history over 150 Ma shows that the horizontal stress difference on the order of 10 MPa observed in the Barnett shale can be explained by the variation in viscoelastic properties within the Barnett shale. Our results highlight the importance of acknowledging viscous deformation of shale gas reservoir rocks to understand the current in-situ state of stress in these reservoirs. A study of frictional properties of a saponite-rich fault gouge from a serpentinite-bearing fault in central Japan is also presented in this thesis. Field characterization of the internal structure of a fault juxtaposing serpentinites and Cretaceous sedimentary rocks show that hydrothermal metasomatic reactions took place at the fault interface which produced peculiar mineral assemblages along the fault plane. The saponite-rich fault gouge resulting from the metasomatic reaction exhibits extremely low coefficient of friction, ~0.1, at wet conditions and strong velocity-strengthening characteristics. The study highlights the importance of geochemical reactions along fault planes which may ultimately control the overall mechanical behavior of major fault zones.

Download or read book Multiscale Investigation of Fluid Transport in Gas Shales written by Robert J. Heller and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on developing an improved understanding of fluid flow in gas shales. The problem is studied at multiple scales, and using a variety of approaches spanning several disciplines. In Chapter 2, Adsorption of Methane and Carbon Dioxide on Gas Shale and Pure Mineral Samples, we present measurements of methane and carbon dioxide adsorption isotherms at 40°C on gas shale samples from the Barnett, Eagle Ford, Marcellus and Montney reservoirs. Carbon dioxide isotherms were included to assess its potential for preferential adsorption, with implications for its use as a fracturing fluid and/or storage in depleted shale reservoirs. To better understand how the individual mineral constituents that comprise shales contribute to adsorption, measurements were made on samples of pure carbon, illite and kaolinite as well. The resultant volumetric swelling strain was also measured as a function of pressure/adsorption. In Chapter 3, Experimental Investigation of Matrix Permeability of Gas Shales, we present laboratory experiments examining the effects of confining stress and pore pressure on permeability. Experiments were carried out on intact core samples from the Barnett, Eagle Ford, Marcellus and Montney shale reservoirs. The methodology we used to measure permeability allows us to separate the reduction of permeability with depletion (due to the resultant increase in effective confining stress) and the increase in permeability associated with Knudsen diffusion and molecular slippage (also known as Klinkenberg) effects at very low pore pressure. By separating these effects, we are able to estimate the relative contribution of both Darcy and diffusive fluxes to total flow in depleted reservoirs. Our data show that the effective permeability of the rock is significantly enhanced at very low pore pressures (