Dissertations / Theses on the topic 'Hydraulic fracturing'
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Chang, Hong. "Hydraulic Fracturing in Particulate Materials." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4957.
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For more than five decades, hydraulic fracturing has been widely used to enhance oil and gas production. Hydraulic fracturing in solid materials (e.g., rock) has been studied extensively. The main goal of this thesis is a comprehensive study of the physical mechanisms of hydraulic fracturing in cohesionless sediments. For this purpose, experimental techniques are developed to quantify the initiation and propagation of hydraulic fractures in dry particulate materials. We have conducted a comprehensive experimental series by varying such controlling parameters as the properties of particulate materials and fracturing fluids, boundary conditions, initial stress states, and injection volumes and rates. In this work, we suggest principle fundamental mechanisms of hydraulic fracturing in particulate materials and determine relevant scaling relationships (e.g., the interplay between elastic and plastic processes).
The main conclusion of this work is that hydraulic fracturing in particulate materials is not only possible, but even probable if the fluid leak-off is minimized (e.g., high flow rate, high viscosity, low permeability). Another important conclusion of this work is that all parts of the particulate material are likely to be in compression. Also, the scale effect (within the range of the laboratory scales) appears to be relatively insignificant, that is, the observed features of fractures of different sizes are similar.
Based on the observed fracture geometries, and injection pressures we suggested three models of hydraulic fracturing in particulate materials. In the cavity expansion or ??e driving model, the fracturing fluid is viewed as a sheet pile (blade) that disjoints the host material, and the cavity expansion occurs at the fracture (blade) front. The shear banding model is also consistent with a compressive stress state everywhere in the particulate material and explains the commonly observed beveled fracture front. The model of induced cohesion is based on the fluid leak-off ahead of the fracture front. The induced cohesion may be caused by the tensile strain near the fracture tip (where the stress state is also compressive), which, in turn, induces the cavitation of the leaked-off fluid and hence capillary forces.
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Pak, Ali. "Numerical modeling of hydraulic fracturing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21618.pdf.
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King, Jeremy Scott. "Acoustical signal during hydraulic fracturing." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=565.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 82 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 42).
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Wu, Ruiting. "Some Fundamental Mechanisms of Hydraulic Fracturing." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10513.
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This dissertation focuses mainly on three topics: (1) mixed-mode branching and segmentation of hydraulic fractures in brittle materials, (2) hydraulic fracture propagation in particulate materials, and (3) hydraulic fracturing in water flooding conditions.
Mixed-mode loading is one of the primary causes of fracture branching and segmentation in brittle materials. We conducted the first laboratory experiments on the mixed mode I+III hydraulic fracturing. We found that a KIII/KI ratio as small as ~1% is sufficient for fracture front segmentation. In reality, such a small mode III component is always expected, for example, due to the small deviations of the fracture shape from planar. Thus, we concluded that fracture segmentation is likely to accompany growth of most, if not all, real hydraulic fractures. We also proposed a theoretical model that captures the main features of experimental observations and indicates the importance of the hydraulic effect of segmentation.
Particulate materials often exhibit pronounced non-linear behavior and yielding even at relatively small loads. In order to adequately describe hydraulic fracturing in particulate materials with low or no cohesion, plasticity at the crack tip must be explicitly considered. We investigated the shear band mechanism of strain localization at the fracture front. This mechanism takes into account the fact that cohesionless material can not bear tension, and is in compression everywhere, including near the fracture front. To verify the shear band hypothesis, we conducted numerical simulations of the plastic deformation at the tip of a fracture in particulate material with strain softening. Our model describes the shear bands by properly placed and oriented dislocations. The model results are consistent with experimental observations.
Water flooding, which in certain important cases, can result in processes resembly hydraulic fracturing by a low-viscosity fluid with extremely high leak-off. It is difficult to simulate this process in the laboratory. To investigate the fracture initiation mechanism in water flooding conditions, we conducted a numerical simulation of fluid injection into particulate material by using the discrete element code PFC2D. We also considered an analytical model of cavity initiation based on the fluidization mechanism. The estimates given by this model fit remarkably well with the numerical simulation results.
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Ahmed, Hussain H. "Perforation screen-out during hydraulic fracturing." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1467.
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Arop, Julius Bankong. "Geomechanical review of hydraulic fracturing technology." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82176.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 283-291).
Hydraulic fracturing as a method for recovering unconventional shale gas has been around for several decades. Significant research and improvement in field methods have been documented in literature on the subject. The heterogeneous nature of shale has made hydraulic fracturing design to be unique for particular site conditions. Actual methods of carrying out fracturing operations and design decisions are also different for various companies in the industry. Hence, there are no standards for decisions in processes such as: formation testing, fracture modeling, choice of fracturing fluid or propping agent selection. This has led to different interpretations of pressure tests and proprietary fracture designs that have not been evaluated for adequacy against any recognized scale. The goal of this thesis is to do an appraisal of hydraulic fracturing in theory and practice. A review is done of the early theoretical work upon which most of the current hydraulic fracturing literature is based. Effort is also made to thoroughly cover the core aspects of fracture modeling and practical operations with a view to shedding light on the strength and drawbacks of current methodologies. The thesis focuses on the geo-mechanics of the process thus less emphasis is laid on post fracturing operations. It is hoped that this will help establish the basis for a standard framework to guide fracturing design. Finally, the ambiguity of nomenclature in oil and gas circles has led to considerable confusion in conducting academic work. For this reason, effort was made in the thesis to clearly define the various terminology.
by Julius Bankong Arop.
M.Eng.
7
Klein, Michael. "Hydraulic fracturing and shale gas extraction." Kansas State University, 2012. http://hdl.handle.net/2097/15160.
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Master of ScienceDepartment of Chemical Engineering
James Edgar
In the past decade the technique of horizontal drilling and hydraulic fracturing has been improved so much that it has become a cost effective method to extract natural gas from shale formations deep below the earth’s surface. Natural gas extraction has boomed in the past few years in the United States, enough that it has driven prices to an all time low. The amount of natural gas reserves in the U.S. has led to claims that it can lead the country to energy independence. It has also been touted as a cleaner fuel for electricity generation and to power vehicles. This report explains hydraulic fracturing and horizontal drilling particularly with regards to utilizing the techniques for natural gas extraction from shale gas. It also discusses the environmental impact due to the drilling and gas extraction. It demonstrates that although the natural gas beneath the U.S. is a valuable resource, the impacts to the planet and mankind are not to be taken lightly. There is the potential for the effects to be long term and detrimental if measures are not taken now to control them. In addition although on the surface natural gas seems to be a greener fuel, particularly in comparison to gasoline, it is also considered worse for the environment.
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Buday, Amanda T. "Fracturing Illinois: Fields of Political Contention in Hydraulic Fracturing Regulatory Policy." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1267.
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This dissertation examines the interactions between social movement organizations and a variety of state and municipal targets of movement activity during the construction of the Illinois Hydraulic Fracturing Regulatory Act (HFRA). Hydraulic fracturing is a controversial method of oil and gas extraction which created an unusual amount of public interest and participation in policy construction. This dissertation provides an overview of the political environment in Illinois during the legislative negotiations for the HFRA, outlining the playing field of political negotiations, and the relative positioning of social movement actors competing for influence in that field. Additionally, I examine the causes and consequences of conflict between coalition partners opposed to fracking, focusing on the impact of differential resources, expertise, and institutional legitimacy. Using data from interviews with organization leaders from industry and environmental coalitions, key informants from government bureaus, and participant observation at public meetings, my research contributes to the political process literature by elaborating the heterogeneity of the state’s interests in political challenges and revealing cleavages within social movement coalitions.
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Gonçalves, da Silva Bruno Miguel. "Fracturing processes and induced seismicity due to the hydraulic fracturing of rocks." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107063.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 449-458).
Hydraulic fracturing is a method used routinely in oil and gas exploitation and in engineered geothermal systems. While used frequently, there are aspects of hydraulic fracturing, such as the propagation of the newly-created fractures and interaction between natural and newly-created fractures, which are not well understood. Since data from field hydraulic stimulations may be difficult to obtain and interpret, laboratory testing and numerical modeling play a major role in understanding the hydraulically fracturing processes. A test setup was developed to simultaneously apply a vertical stress to rock specimens and a hydraulic pressure to pre-cut flaws with various geometries, leading to the initiation and propagation of new cracks. The test setup allowed one to obtain high-resolution and high-speed video images of the hydraulic fracturing processes and to monitor acoustic emissions in Barre granite specimens subjected to constant vertical stresses of 0 or 5 MPa. The imaging data were used to determine the mechanisms of development of the visible fractures produced during the tests. The acoustic emission data were used to estimate the mechanisms responsible for the development of micro-cracks. In order to understand the fracturing behavior of the hydraulically loaded rock specimens, particularly the effect of the ratio between the water pressure applied in the flaws (WP) and the vertical load applied to the specimen (VL), a finite element analysis was performed using the same loading conditions of the experiments. The experiments showed that most visible cracks observed were tensile and that the patterns of the hydraulic fractures produced were strongly dependent on the vertical load applied. They also showed that the water pressure necessary to propagate fractures is dependent on the vertical load and on the flaw geometry. The numerical analysis showed that the ratio WP/VL plays a crucial role in the magnitude and shape of the stress field around a flaw tip, and therefore in the location of tensile and shear fracture initiation. The study of micro-seismic events indicated that tensile and shear micro-cracks frequently developed before visible tensile cracks in the tests with no and 5 MPa of vertical load, respectively. The results presented improve the knowledge of the physical processes involved in the hydraulic fracturing of rocks.
by Bruno Miguel Gonçalves da Silva.
Ph. D.
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Shimizu, Hiroyuki. "Distinct element modeling for fundamental rock fracturing and application to hydraulic fracturing." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120827.
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Kekacs, Daniel. "Treatment and Characterization of Hydraulic Fracturing Fluids." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406297620.
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Li, Qiuyi Bing. "Acoustic emissions in hydraulic fracturing of Barre granite." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99581.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 147-148).
The purpose of this work is to observe acoustic emissions (AE) generated by laboratory scale hydraulic fracturing of Barre granite specimens with single or double flaw geometry. The scope of this work covers the experimental setup and subsequent analyses of these acoustic emissions, which in essence are elastic waves generated by displacements occurring within the rock specimen. Acoustic emissions can be analysed in a number of ways, whether individually or grouped together into events when a number of emissions arrive together. Individual emissions can be analysed for their amplitude, energy, or their frequency content while the source location and source mechanism can be inferred from events. The AE data are analysed in conjunction with water pressure, high resolution images, and high speed video taken during the experiment. Section 3 of this work outlines the selection and subsequent modification of the AE acquisition system with a specific focus on capturing AE at the end of each experiment in order to compare results to high speed video. This section describes the initial equipment selection, as well as initial experiments where it was noted that crucial data were missing around the time of the fracture event. This issue was largely resolved by modifying the system parameters as well as upgrading the PC supporting the AE acquisition cards. Section 4 of this work describes analysis of one experiment, providing an in-depth start-to-finish account of the nature of acoustic emissions at different phases of the experiment. This section also considers all of the hydraulic fracture experiments performed at different vertical loads and specimen flaw geometries, and draws some tentative conclusions regarding hydraulic fracturing in granite.
by Qiuyi Bing Li.
S.M.
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Ng, Man Yin Albert. "Modelling of hydraulic fracturing in cement bentonite geomaterials." Thesis, University of Cambridge, 2009. https://www.repository.cam.ac.uk/handle/1810/283851.
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Asif, Ehsan Syed Mortuza. "Three Essays on the Economics of Hydraulic Fracturing." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/72130.
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Hydraulic fracturing has been increasingly used in the USA to economically extract natural
gas and oil from newly discovered shale plays. Despite new, more severe, and long term
impacts of hydraulic fracturing compared to conventional drilling, regulatory practices are
mostly implemented by states that regulate with older regulations that were were written
before the widespread use of hydraulic fracturing. This dissertation presents three essays on
the economics of hydraulic fracturing. A standard renewable lease in hydraulic fracturing
runs for a five-year primary term. The first essay examines the effect of initial contract length
on extraction behavior and social costs. It finds that the rate of extraction decreases over
time for both, the social planner and the private extractor. In addition, the social planner
has a more stable extraction path compared to the private extractor. Holding other things
equal, if the social planner seeks to induce a private extractor to leave a higher in situ stock
un-extracted, then the optimal contract duration is longer. Simulations illustrate the magnitude
of social costs inherent in hydraulic fracturing and non-optimal fixed contract lengths. The second essay investigates the impact of the significantly increased bonding requirements
for horizontal wells introduced in West Virginia in December, 2011, on the probability of
violation committed by those wells. Results suggest that the increased bonding requirement
has reduced the probability of violation by 2.6 to 3.2 percentage points. Moreover, it slightly
reduces the number of violations done by horizontal wells. Finally, the third essay explores
several aspects of Act-13, introduced on February 14, 2012, by Pennsylvania. This act imposes new fees that are assessed annually for fifteen years, on all unconventional gas wells in Pennsylvania. This chapter explores the impacts of Act-13 on the likelihood of an unconventional well's shut-down, rate of extraction, and probability of violation. Results suggest that wells incurring this increased fee schedule have a significantly higher likelihood (more than three times) of shut-down. Also, Act-13 have reduced the extraction rate, and the probability of violation committed by unconventional wells in Pennsylvania.Ph. D.
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Josifović, Aleksandar. "Reducing the environmental impact of hydraulic fracturing pumps." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27496.
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Eshiet, Kenneth Imo-Imo. "Modelling of hydraulic fracturing and its engineering application." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/3148/.
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The Hydraulic Fracturing process and its engineering applications have been studied and reported in this thesis. The Distinct Element Method (DEM) was adopted as the main and preferred numerical technique because of its distinctive features and advantages. This method allows the phenomenon to be modelled and viewed microscopically at the inter-particle level by conceptualising the rock mass as an assembly of discrete particles interacting with each other via contacts. This method allows for a more detailed and dynamic monitoring of the hydraulic fracturing process. Sequel to a detailed review on the study of the hydraulic fracturing phenomenon, the research was extended to investigate specific cases of applications of hydraulic fracturing in geo-mechanical and environmental problems. Examples of such cases include carbon dioxide injection and storage in a reservoir system, and the behaviour of naturally occurring faults subjected to hydrostatic fluid pressures. The key factors governing the geo-mechanical responses of porous media (rocks), including reservoir formations were identified and further examined to ascertain the following: the role and inter-relationship between operating and material/fluid variables such as injection flow rate, fluid pressure, and interstitial velocity; type and pattern of fracture propagation; influence of environmental conditions as well as the configuration of the well-reservoir system, amongst others. Because of broad similarities in enabling conditions, analyses and applications of the phenomenon were also extended to study the sand production process. However, since the emphasis of the study was on identifying and examining the controlling variables as well as establishing patterns of sanding production rates rather than the study of the cavitation process, investigations were conducted using a finite element procedure; moreover, the limit of computational capacity has prevented a large scale DEM model for such problems. Modelling results show that fracturing mode, pattern and intensity are highly dependent on operating and environmental conditions; the reservoir erosion processes also indicate likewise tendencies. The numerical modelling techniques adopted and results obtained facilitate an improved understanding of geo-mechanical mechanisms at sub-surface systems, and could be further improved for industrial applications, such as site evaluation and assessment of the efficiency of stimulation techniques.
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Longstaff, Andrew John. "Synthesis of functionalised polysaccharides for hydraulic fracturing applications." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12180/.
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This thesis involves the chemical modifications of the highly reactive primary hydroxyl groups of 2-hydroxyethyl cellulose (HEC) to give rise to possible reaction sites with group(IV) metal-based crosslinkers, leading to the formation of viscous gel materials and possible applications in hydraulic fracturing. This is to offer an alternative to guar, a popular crosslinkable polysaccharide that is obtained from natural products and used routinely in fracturing applications, as its availability is often cast in doubt from year to year due to fluctuating crop harvests. In Chapter 1, a general introduction to hydraulic fracturing is provided, including details on the types of polysaccharides, crosslinking agents and chemical additives utilised in fracturing fluids, along with possible mechanisms of crosslinking. This chapter also introduces Click chemistry and ring opening polymerisation (ROP) techniques used in this work. Chapter 2 describes the use of trehalose, a disaccharide molecule, as a model compound for HEC as it has acomparable core skeleton structure, reactivity and solubility properties. The primary hydroxyl groups were converted to thiol groups via a three-step process. Each step was fully characterised by 1D and 2D NMR spectroscopy, and FT-IR spectroscopy. The thiolated trehalose was then utilised in a UV mediated thiol-ene Click reaction with a catechol-containing norbornene compound. In Chapter 3, HEC is modified with small carbonyl-containing molecules via acid catalysed condensation reactions to impart diol or catecholic end group functionalities. The surface esterification of HEC via the ring opening of succinic anhydride using DMAP as a catalyst is also performed, leading to acid end group functionality. These materials were characterised using inverse-gated 13C NMR spectroscopy and FT-IR spectroscopy. Chapter 4 describes the synthetic methods used to impart thiol functionality to HEC. This was initially based on the knowledge gained from Chapter 2, but ultimately was found to be unsuccessful when applied to HEC. However, an alternate one-pot synthetic route utilising triphenyl phosphine, carbon tetrabromide and a sulfur nucleophile of either sodium thiobenzoate or potassium thioacetate was successfully used. Thiolated HEC, with approximately 15% of the primary hydroxyl groups converted to SH, was then reacted with the aforementioned norbornene compound in a UV mediated thiol-ene Click reaction. Inverse-gated 13C NMR, DEPT 13C NMR and FT-IR spectroscopy were useful characterisation methods. Chapter 5 investigates the utilisation of HEC as a macroinitiator in the anionic ring opening polymerisation (ROP) of the latent AB2 monomer glycidol. This will impart numerous hydroxyl groups within close proximity to each other, increasing the likelihood of participating in crosslinking reactions with group(IV) metal ions. The graft copolymers were purified by dialysis, then characterised by inverse-gated 13C NMR and DEPT 13C NMR spectroscopy, FT-IR spectroscopy, TGA and SEC. HEC-g-polyglycerol was then also utilised as a macroinitiator in the tin(II) ethylhexanoate-catalysed ROP of ε-caprolactone, to afford the novel graft copolymers HEC-g-polyglycerol-g-PCLn, where n = 10, 50, 100 or 250. Upon grafting, the hydroxyl end groups of the flexible PCL chains will be further away from the HEC backbone, thus reducing steric hindrance and increasing the likelihood of interacting with group(IV) metal ions of crosslinking agents. The two graft copolymers with the smallest PCL chains retained their water solubility, whilst the longer PCL chain graft copolymers were found to be hydrophobic. All of the PCL containing graft copolymers were fully characterised using 1D and 2D NMR spectroscopy, SEC, TGA, DSC and FT-IR spectroscopy. AFM analysis also determined the structural architectures of these graft copolymers, with a capillary-like network afforded when n = 10, and larger globules afforded when n = 250. It was calculated that each globule actually represents one individual macromolecule. Chapter 6 describes crosslinking reactions carried out with guar and functionalised HEC materials. Triethanolamine-based zirconium crosslinkers containing different molar equivalents of water added during synthesis were shown to afford different delay times in the gelation of aqueous guar solutions. Crosslinking efficacy was shown to be dependent on the age of the crosslinker, with crosslinkers aged seven months affording much longer delay times. The six-coordinate alkanolamine ligand analogues N,N,N’,N’-tetrakis(2-hydroxyethyl)ethylenediamine (THEED) and N,N,N’,N’-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) were used to synthesise the complexes [Ti(THEED)]2, [Zr(THEED)]2 and [Zr(THPED)]2. These complexes afforded no crosslinking ability with guar. The THEED-containing complexes were successfully recrystallised and single crystal X-ray diffraction crystallography was used to determine the structures of the complexes. These were found to be seven-coordinate dimers, with a binucleating oxygen atom from each ligand acting as a bridge to form a central M2O2 ring. ESI-MS data also helped confirm this. The [Ti(THEED)]2 complex was found to be a chiral species showing signs of disorder, whilst the [Zr(THEED)]2 complex was found to be centrosymmetric with a planar M2O2 ring. The structure of the [Zr(THPED)]2 complex could not be identified by X-ray crystallographic methods as single crystals could not be isolated, however, ESI-MS evidence supports it also being a seven-coordinate dimer. Aqueous solutions of the graft copolymers HEC-g-polyglycerol, HEC-g-polyglycerol-g-PCL10, HEC-g-polyglycerol-g-PCL50 and the functionalised polymer succinylated HEC were evaluated for their crosslinking abilities with a triethanolamine zirconate crosslinker and a α-hydroxycarboxylic acid zirconate crosslinker. All of the graft copolymers showed no signs of gelation with either crosslinking agent. Succinylated HEC showed no signs of gelation with the triethanolamine zirconate crosslinker. However, gelation of succinylated HEC was induced by the addition of α-hydroxycarboxylic acid zirconate crosslinker. Unfortunately, this was with a 3.0 wt.% polymer concentration, which is greater than the limits utilised in industrial fracturing applications. In Chapter 7, general conclusions and future perspectives for the work are discussed.
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Fallahzadeh, Abarghooei Syed Hassan. "Simulations of hydraulic fracturing initiation in perforated boreholes." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/1332.
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The mechanism of initiation and propagation of hydraulic fracture from cased hole perforated wellbores is investigated through analytical, numerical and experimental studies. A new model was developed for arbitrarily oriented wellbore and perforation to predict the fracture initiation pressure, location and orientation, along the perforation length. In addition, scaled experimental and numerical studies were carried out to validate the analytical model and to investigate the effects of fluid viscosity and injection rate on fracture geometry.
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Wang, Wenxin. "Methodologies and new user interfaces to optimize hydraulic fracturing design and evaluate fracturing performance for gas wells." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3268.
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This thesis presents and develops efficient and effective methodologies for optimal
hydraulic fracture design and fracture performance evaluation. These methods
incorporate algorithms that simultaneously optimize all of the treatment parameters while
accounting for required constraints. Damage effects, such as closure stress, gel damage
and non-Darcy flow, are also considered in the optimal design and evaluation algorithms.
Two user-friendly program modules, which are active server page (ASP) based, were
developed to implement the utility of the methodologies. Case analysis was executed to
demonstrate the workflow of the two modules. Finally, to validate the results from the
two modules, results were compared to those from a 3D simulation program.
The main contributions of this work are:
An optimal fracture design methodology called unified fracture design (UFD)
is presented and damage effects are considered in the optimal design
calculation.
As a by-product of UFD, a fracture evaluation methodology is proposed to
conduct well stimulation performance evaluation. The approach is based on
calculating and comparing the actual dimensionless productivity index of
fractured wells with the benchmark which has been developed for optimized
production.
To implement the fracture design and evaluation methods, two web ASP
based user interfaces were developed; one is called Frac Design (Screening),
and the other is Frac Evaluation. Both modules are built to hold the following
features.
o Friendly web ASP based user interface o Minimum user input
o Proppant type and mesh size selection
o Damage effects consideration options
o Convenient on-line help.
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Yi, Tongchun. "Numerical simulation of fluid loss in hydraulic fracturing treatments." Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/779.
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CACHAY, LEONARDO RODIN SALAS. "PROPPANT FLOWBACK IN OIL WELLS STIMULATED BY HYDRAULIC FRACTURING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6513@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROUm dos principais objetivos da engenharia de petróleo é desenvolver e aplicar técnicas capazes de aumentar a produtividade de poços de petróleo, incluindo a estimulação da formação através de operações que aumentem a permeabilidade da rocha-reservatório e facilitem o escoamento do fluido. Dentre as técnicas de estimulação, a mais utilizada é o fraturamento hidráulico, a qual tem viabilizado a exploração em cerca de 40% dos poços produtores de petróleo em todo o mundo. Durante o fraturamento hidráulico, um material granular conhecido como material de sustentação ou propante, é injetado nas fraturas recém-criadas com o objetivo de mantê-las abertas e garantir-lhes condições de alta permeabilidade. A produção de material de sustentação (proppant flowback) é termo usado para descrever o refluxo do propante para o interior do poço, juntamente com o hidrocarboneto produzido. O controle do fluxo de propante representa um grave desafio para a indústria de petróleo, pois pode causar graves problemas operacionais e de segurança, relacionados com o desgaste dos equipamentos de produção, problemas econômicos associados ao custo de limpeza, paralisação das operações e intervenção no tratamento da fratura, problemas ambientais relacionados com a disposição de sólidos impregnados por hidrocarbonetos, etc. Neste contexto, a presente dissertação apresenta um estudo detalhado dos principais tipos de propante e de suas propriedades, bem como descreve os mecanismos que influem no refluxo do material de sustentação da fratura e analisa os principais modelos apresentados na literatura para previsão deste fenômeno. Uma retroanálise considerando os dados de campo em 22 poços da Petrobrás, localizados em Sergipe, permite uma comparação da eficiência entre quatro dos modelos, desenvolvidos com base em resultados de ensaios de laboratório, indicando suas vantagens e desvantagens para aplicação na prática da engenharia.
One of the main objectives of petroleum engineering is to develop and to apply techniques aiming the productivity increase of oil fields, including the stimulation of the rock through operations that increase the permeability of the oil reservoir and makes the flow of the fluid toward the well more efficient. Among the stimulation techniques, the most used is the hydraulic fracturing, carried out in about 40 percent of the producing oil wells around the world. During hydraulic fracturing, a granular material known as proppant, is injected into the just created fractures with the objective to keep them open and in order to guarantee the designed conditions of high permeability. Proppant flowback is the technical terminology employed to describe the flow of proppant from the fracture to the interior of the oil well, together with the produced hydrocarbon. An efficient and reliable control of this problem is still a major challenge to the oil industry, given the serious operational and security problems that it may cause, including costs of interrupted operations, cleaning measures, environmental contamination risks associated with the disposal of residues impregnated by oil, etc. In this context, the present thesis presents a detailed description on the main proppant materials and their engineering properties and available treatments, as well as on the physical mechanisms that control the flowback phenomenon. Several simple models published in the literature, that permit the forecast of proppant flowback in a fast and easy way, are also presented and discussed. Finally, a back-analysis considering the actual conditions in 22 Petrobras oil wells located in Sergipe was also carried out, what permitted a comparison among the results calculated according 4 prediction models, putting in evidence their advantages, shortcomings and adequacy as a design or control tool in the design and exploration of oil fields stimulated by hydraulic fracturing.
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ESCOBAR, RENATO GUTIÉRREZ. "INVESTIGATION OF HYDRAULIC FRACTURING THROUGH ANALYTICAL AND NUMERICAL MODELS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=28072@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O processo de fraturamento hidráulico tem sido amplamente usado para aumentar o volume de petróleo e gás extraído na indústria petroleira. Durante a injeção de fluido, uma região determinada do reservatório é fraturada com a finalidade de aumentar a permeabilidade do meio poroso, de tal forma que o fluxo do fluido desde o reservatório para o poço seja favorecido notoriamente. Porém, este processo pode ocasionar danos ambientais tais como contaminação de aguas subterrâneas, vazamentos de gás, fraturas indesejadas nas camadas capeadoras pela injeção de agua e atividade sísmica fazendo primordial um estudo rigoroso do fraturamento hidráulico com a finalidade de reduzir os riscos potenciais associados a esta operação. Umas das metodologias usadas para projetar o fraturamento hidráulico é a simulação computacional. É possível determinar o volume injetado e a potência da bomba de injeção necessária para obter a geometria de fratura (comprimento, abertura e altura) desejada. A modelagem numérica através de elementos coesivos acoplados do processo de fraturamento hidráulico pode ser efetuada considerando o processo transiente ou permanente, tendo geometrias da fratura e curvas de injeção diferentes. Neste trabalho foi simulado numericamente o modelo KGD nos regimes de fluxo transiente e permanente para dois casos de estudo, (1) injeção numa única camada e (2) injeção em três camadas com contraste de tensões e poropressões entre elas. O estudo numérico foi desenvolvido usando o método dos elementos finitos com modelo de zona coesiva no software Abaqus o qual foi comparado com as soluções analíticas do KGD no regime dominado pela rigidez (Vértice-K) para uma camada e de Simonson e Fung para três camadas.
The hydraulic fracturing process has been widely used to improve oil and gas recovery in the petroleum industry. During the fluid injection, the desired section of rock formation is fractured in order to increase the permeability of the medium that can facilitate the flow of oil to a producing well. However, this process can lead to potential environmental risks such as seismic activity, unwanted fractures in cap layers by water injection, water contamination and gas leakage making primordial to develop a rigorous study in order to reduce this environmental risks associated to hydraulic fracturing. One of the studies developed to design the hydraulic fracturing is computational simulation to determine the fluid volume and hydraulic horsepower required in order to produce the wanted fracture geometry (length, opening and height). The numerical modelling of fracturing process by using fully coupled cohesive element hydraulic can be carried out considering either a steady state or a transient analysis, which modify the fracture geometry and injection pressure. In this work, the KGD model is simulated in transient and steady analysis for two cases: (1) injection in a single layer formation and (2) injection in tri-layered formation with stress and porepressure contrast between them. The numerical simulation of a hydraulic fracturing is carried out using the finite element method with the zone cohesive model in Abaqus whose results are compared with analytical solutions of toughness-dominated propagation regime for the one layer formation model and Simonson and Fung analytical solutions for tri-layered formations model.
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Bond, Laura. "Impacts of Hydraulic Fracturing Infrastructure on Storm Runoff Characteristics." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469028846.
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Ghasemzadeh, Shahram M. S. "Effect of Hydraulic Fracturing Waste in Wastewater Treatment Processes." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471254155.
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Consolazio, Nizette A. "Chemical Interactions of Hydraulic Fracturing Biocides with Natural Pyrite." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1071.
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In conjunction with horizontal drilling, hydraulic fracturing or fracking has enabled the recovery of natural gas from low permeable shale formations. In addition to water, these fracking fluids employ proppants and up to 38 different chemical additives to improve the efficiency of the process. One important class of additives used in hydraulic fracturing is biocides. When applied appropriately, they limit the growth of harmful microorganisms within the well, saving energy producers 4.5 billion dollars each year. However, biocides or their harmful daughter products may return to the surface in produced water, which must then be appropriately stored, treated and disposed of. Little is known about the effect of mineral-fluid interactions on the fate of the biocides employed in hydraulic fracturing. In this study, we employed laboratory experiments to determine changes in the persistence and products of these biocides under controlled environments. While many minerals are present in shale formations, pyrite, FeS2(s) is particularly interesting because of its prevalence and reactivity. The FeII groups on the face of pyrite may be oxidized to form FeIII phases. Both of these surfaces have been shown to be reactive with organic compounds. Chlorinated compounds undergo redox reactions at the pyrite-fluid interface, and sulfur-containing compounds undergo exceptionally strong sorption to both pristine and oxidized pyrite. This mineral may significantly influence the degradation of biocides in the Marcellus Shale. Thus, the overall goal of this study was to understand the effect of pyrite on biocide reactivity in hydraulic fracturing, focusing on the influence of pyrite on specific functional groups. The first specific objective was to demonstrate the effect of pyrite and pyrite reaction products on the degradation of the bromine-containing biocide, DBNPA. On the addition of pyrite to DBNPA, degradation rates of the doubly brominated compound were found to increase significantly. DBNPA is proposed to undergo redox reactions with the pyrite surface, accepting two-electrons from pyrite, and thus becoming reduced. The primary product is the monobrominated analogue of DBNPA, 2-monobromo-3-nitrilopropionamide (or MBNPA). The surface area-normalized first-order initial degradation rate constant was found to be 5.1 L.m-2day-1. It was also determined that the dissolution and oxidation products of pyrite, FeII, S2O32- and SO42- are unlikely to contribute to the reduction of the biocide. Taken together, the results illustrate that a surface reaction with pyrite has the ability to reduce the persistence of DBNPA, and as a consequence change the distribution of its reaction products. The second objective was to quantify the influence of water chemistry and interactions with pyrite on the degradation of the sulfur-containing biocide. Dazomet readily hydrolyzes in water due to the nucleophilic attack of hydroxide (OH-) anions. Thus the half-life of dazomet during the shut-in phase of hydraulic fracturing will decrease with increasing pH: 8.5 hours at pH 4.1 to 3.4 hours at pH 8.2.Dazomet degradation was rapidly accelerated upon exposure to the oxidized pyrite surface, reacting five times faster than hydrolysis in the absence of pyrite at a similar pH. The products measured were identical to those identified on hydrolysis (methyl isothiocyanate and formaldehyde) and no dissolved iron was detected in solutions. This suggests that the dithiocarbamate group in dazomet was able to chemisorb onto the oxidized pyrite surface, shifting the electron density of the molecule which resulted in accelerated hydrolysis of the biocide. The third objective explored the reactivity of various biocide functional groups due to the addition of pyrite. Several elimination mechanisms were identified, and tied to the reactivity of the specific functional group involved. The addition of pyrite led to accelerated degradation of dibromodicyanobutane. This is because the bromine (-Br) group is easily reduced. For methylene bis(thiocyanate), hydrolysis was a noteworthy elimination mechanism since the thiocyanate (-SCN) functionality is a good leaving group. Benzisothiazolinone and methyl isothiazolinone were stable at low pH due to the stabilizing donor-acceptor interactions between the organic biocides’ carbonyl (–C=O) groups and salts in the solution. This body of work has illustrated that pristine pyrite can undergo redox reactions with brominated biocides used in hydraulic fracturing, reducing their persistence and altering the product distribution. This will change the efficacy and the risks associated with the use of these biocides in shales containing pyrite, particularly at lower pH where organic compounds are more stable to hydrolysis. However, at higher pH hydrolysis becomes more important, and additional studies will need to be conducted to investigate the pyrite contribution under these conditions. Conversely, the FeIII surface groups on oxidized pyrite can catalyze the hydrolysis of dazomet and may do so for other labile, sulfur-containing biocides as well. Overall, this research has shown that the physicochemical properties (such as the acid dissociation constant and the standard reduction potential) that govern the environmental reactivity of a molecule can be used to anticipate its reactivity in hydraulic fracturing.
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Mighani, Saied 1989. "Some rock mechanics problems with application for hydraulic fracturing." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122224.
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Thesis: Ph. D. in Geophysics, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 185-205).
Hydraulic fracturing is an essential tool used to enhance connectivity in shale gas reservoirs by maximizing the intersection between the hydraulic fracture (HF) and pre-existing natural fractures (NF) or faults. The technique is most effective when the hydraulic fracture crosses natural fractures rather than arresting on them. Experiments conducted to examine the interaction between HF and artificial pre-existing faults suggest that the coupling of diffusivity and fault slip is an important element of the HF-fault interaction problem. Fault slip, once activated is associated with an apparent increase in diffusivity. Whether the hydrofracture crosses or arrests on the pre-existing fault is also affected by surface roughness, differential stresses, and fault slip mode (i.e., stable or stick-slip sliding). Calibrated piezoelectric transducers were used to measure acoustic emissions (AE) generated during HF and fault slip.
Moment tensor analysis of these events was used to distinguish pure tensile, shear, and possibly closure events during the experiments. Seismic moment magnitudes were approximately -7 for events during the initiation of the HF and about -5 for events during fault slip. Such a low ratio of seismic moments for tensile and slip events may explain the small numbers of tensile events recorded during reservoir stimulations. I also studied the time-dependent behavior in shales to gain insight into the post-stimulation efficiency of exploitations. Shale experiences strain hardening and compaction during loading by both isostatic (pressure-driven) and differential stress (shear-driven). Transient creep strain increased linearly with log(time), possibly transitioning to constant rate in timescale of several days. Motivated by the multi-scale nature of heterogeneities in shales, I examined the micromechanics of deformation using the nano-indentation technique.
Elastic and creep moduli found in nano-indentation and triaxial tests agreed within a factor of 2, but within that factor, the creep strength may depend on spatial scale.
by Saied Mighani.
Ph. D. in Geophysics
Ph.D.inGeophysics Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences
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GUIMARAES, GLAUCE DA SILVA. "ANALYSIS OF THE RHEOLOGICAL CHARACTERISTICS OF A HYDRAULIC FRACTURING FLUID." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1989. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33266@1.
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Como parte da linha de pesquisa na área de estimulação de poços de petróleo, foi montado um viscosímetro tubular para análise das características de comportamento reológico de um fluido de fraturamento hidráulico (HPGUAR), dotado de dispositivo para preparação do fluido . Os dados experimentais obtidos foram tratados analiticamente segundo dois tipos de equações constitutivas: as do Modelo de Ostwald, amplamente utilizadas pelos pesquisadores da área de Engenharia de Petróleo, e as do Modelo de Bingham. Pela avaliação dos resultados obtidos, pode-se concluir que parecem ocorrer evidências de que o Modelo de Bingham possa ser mais adequado, por retratar de forma mais independente as contribuições isoladas do atrito viscoso e da componente gerada pela viscosidade plástica, na análise teológica do HPGUAR. Sugere-se que investigações mais detalhadas devam ser conduzidas, posto que eventualmente poderiam ser bastante úteis no esclarecimento da pendência existente nos resultados experimentais obtidos por diversos autores consultados.In order to contribute in the investigation of the stimulation operation of an oil reservoir was built a tubular viscometer to determine the rheological properties of a hydraulic fracturing fluid (HPGUAR). This test rig included a system to prepare the hydraulic fracturing fluid. The experimental results were modelled according to two types of constitutive equations: the Ostwald Model one, widely used in the Petroleum Engineers field, and the Bingham Model one. An evaluation of the experimental results suggests that the Bingham Model should be more adequate than the other one, specifically when it shows the contribuition from the viscous friction and from the plastic viscosity independently, in the determination of the rheological properties of the HPGUAR. More detailed investigations must be carried out, although they should be very usefull in better explaning the differeces obtained among several investigators.
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Hudson, Michael Robert. "Numerical simulation of hydraulic fracturing in tight gas shale reservoirs." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/18351/.
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Hydraulic fracturing of tight gas shales is a relatively new method of producing economically from extremely low permeability reservoirs. Due to the low permeability, it is crucial that fracturing treatments are able to efficiently create regions of enhanced permeability in the reservoir. The mechanical properties of prospective shale mean that stress interactions between adjacent fractures can be of real consequence to the efficiency of the treatment, and alternative treatments to mitigate these effects have been designed. The aim of this research is to conduct numerical simulation of alternative treatment designs, and objectively evaluate critical parameters. In particular, key aspects of the socalled Texas Two Step method are simulated. This treatment aims to create zones of altered stress anisotropy between pressurised fractures. This study examines the behaviour of said zones as the distance between the fractures is altered, in parallel with literature describing the method. Explanations for unusual fracture curvature behaviour are provided. Further studies examine fracture reorientation within a modified stress field such as that created by the treatment. Rates of reorientation are measured under varying levels of stress anisotropy, initial fracture length and orientation to the stress field. The influence of pre existing natural fractures on the path of a hydraulic fracture is investigated through further simulations. The effects of natural fracture permeability and interface properties are studied. The impact of shear stress caused by a propagating fracture is also examined, and the possible implications for interpretation of microseismic data discussed. Finally, a new treatment for simultaneous fracturing with reduced stress shadowing is proposed and simulated.
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Alampi, Ann M. "Effectiveness of microseismic monitoring for optimizing hydraulic fracturing in California." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90664.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (page 33).
Hydraulic fracturing has fundamentally changed the oil and gas industry in the past 10 years. Bakersfield, California provides a unique case study because steam injection, a type of hydraulic fracturing, has been used there for more than 60 years. Seven companies, varying in size and strategy, use steam injection in California. Some of these companies use microseismic monitoring technologies to maximize production from hydrocarbon reservoirs. In this study, the effectiveness of microseismic monitoring to maximize production in California is explored. This is accomplished by comparing trends in oil and gas production volumes with each company's use of microseismic monitoring. This project found that operators that use microseismic most extensively have not achieved a competitive advantage over other operators. This means that substantial investments in monitoring research, installation and data interpretation have not paid off and may not be worthwhile. This result should help companies improve their current projects and shape future investment decisions.
by Ann M. Alampi.
S.B.
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Hollstein, Matthew S. "Teaching About Hydraulic Fracturing in Ohio High School American GovernmentClassrooms." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1426807930.
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Sajja, Mounika. "Correlation between Indoor Radon Concentrations and Hydraulic Fracturing in Ohio." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1494633736877779.
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Sekhejane, Moagi Cable Benty. "A systematic-theological exploration of hydraulic fracturing in South Africa." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/61201.
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We live in times where technology is central to every little detail of human existence. As a result of this, the world's civilisation has developed quite extensively. The subsequent escalating awareness of an environmental crisis has led to widespread societal and religious reflection on the human relationship with the earth. Such reflection has strong patterns in most religious traditions in the realms of ethics and cosmology and can be seen as a subset – and ramification of a theology of nature. Therefore, eco-theology not only tries to address our understanding of reality but makes us aware that we are part of nature, there is no 'us' and 'them' but all of us are part of nature, that is, ontological integrity.
At the present moment with the escalating energy crisis in South Africa's power utility, Eskom's struggling to meet the demand of the country, the industry is embarking on exploratory high volume hydraulic fracturing (fracking) to extract the huge reserves of natural gas contained in shale rock. Energy companies want to harness the untapped reserves of natural gas below the Karoo area as seen on the map below. There is a growing debate around this new venture as environmentalists, ecologists, theologians and communities have mixed reactions or feelings about this. This ranges from issues such as risks of air, soil and water pollution, methane escape, earth tremors and quakes linked between fracking technology and climate change. There are both pro and anti-campaigns around fracking.
The question is; how do we move forward? What is our theological response as a society in addressing the issue?Dissertation (MA (Theology))--University of Pretoria, 2016.
Dogmatics and Christian Ethics
MA (Theology)
Unrestricted
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al-Najafi, Falah. "Dynamic fluid loss characteristics of linear fracturing gels and associated permeability impairment." Thesis, Heriot-Watt University, 1986. http://hdl.handle.net/10399/862.
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Valencia, Karen Joy Petroleum Engineering Faculty of Engineering UNSW. "Optimising hydraulic fracture treatments in reservoirs under complex conditions." Awarded by:University of New South Wales. School of Petroleum Engineering, 2005. http://handle.unsw.edu.au/1959.4/23318.
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Growing global energy demand has prompted the exploitation of non-conventional resources such as Coal Bed Methane (CBM) and conventional resources such as gas-condensate reservoirs. Exploitation of these resources primarily depends on stimulation by hydraulic fracturing. Traditional hydraulic fracturing practices, however, are in many ways inadequate in addressing difficulties associated with these non-conventional and conventional resources. For example, complex in-situ stress distribution, large material property contrasts and unique production mechanism complicate the implementation of hydraulic fracture treatments in CBM and gas-condensate reservoirs respectively. An integrated approach to optimise hydraulic fracture treatments in reservoirs under complex conditions is developed in this thesis. The optimisation methodology integrates a fracture geometry model which predicts fracture geometry for a given set of treatment parameters, a production model which estimates reservoir productivity after stimulation and an economic model which calculates net present value. A stochastic optimisation algorithm combining features of evolutionary computations is used to search for the optimum design. Numerical techniques such as finite element analysis, iterative semi-analytical methods and evolutionary computation are also used. The following are the major contributions of this thesis: 1. A three-dimensional hydraulic fracture geometry model which accounts for poroelastic effects, in-situ stress and rock material properties, has been developed to provide a more realistic description of the hydraulic fracture geometry. This served as a tool to visualise hydraulic fracture propagation for a given in-situ stress distribution, rock material properties and treatment parameters. Furthermore, by accounting for poroelastic effects, it is possible to identify the causes of exceptionally high treatment pressures. 2. An innovative production model was formulated in this thesis to quantify the well deliverability due to hydraulic fracturing. The production model has been used for a range of production scenarios for CBM and gas-condensate reservoirs such as: multiple wells at arbitrary locations and various well types (stimulated and unstimulated wells). 3. The optimisation methodology presented in this work provides a platform for operators to assess risks and gains associated with different field development scenarios. The added feature of sub-optimal NPV contouring provided flexibility to calibrate the treatment design in real-time. The strength of the optimisation methodology lies in the flexibility to: (1) impose design constraints, (2) optimise multiple variables and (3) simulate multiple objectives.
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BARBOSA, JAIME ANDRES CASTANEDA. "NUMERICAL SIMULATION OF HYDRAULIC FRACTURING BY THE EXTENDED FINITE ELEMENT METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31482@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Um dos principais objetivos da engenharia de petróleo é desenvolver e aplicar técnicas capazes de aumentar a produtividade de poços de petróleo, incluindo a estimulação do poço por operações de fraturamento hidráulico. Estudos sobre a propagação de fraturas podem ser feitos analiticamente para algumas situações simplificadas envolvendo homogeneidade, isotropia e condições de contorno simples do meio geológico, ou pela aplicação de métodos numéricos, como o método dos elementos finitos, para casos mais complexos. A presente pesquisa apresenta análise numérica de fraturamento hidráulico utilizando o método estendido dos elementos finitos (XFEM), em conjunto com o modelo constitutivo de dano da Zona Coesiva (MZC). No método estendido dos elementos finitos a geometria da fratura se torna independente da malha, permitindo a propagação da fratura através do domínio, dispensando sucessivas gerações de malha necessárias na aplicação do método convencional dos elementos finitos. Os resultados numéricos obtidos foram comparados com soluções analíticas assintóticas no caso limite em que o regime da propagação é dominado pela rigidez da rocha, obtendo uma boa concordância. Adicionalmente, foram investigados os efeitos de diferentes parâmetros do fluido de injeção e as características de propagação da fratura quando a interface entre diferentes camadas geológicas é inclinada, mostrando dependência do ângulo de inclinação, das propriedades do material e das tensões in-situ.
One of the main objectives of petroleum engineering is to develop and apply techniques capable of increasing the productivity of oil wells, including the stimulation of well by hydraulic fracturing operations. Studies on the propagation of fractures can be done analytically for some simplified situations involving homogeneity, isotropy and simple boundary conditions of the geological medium, or by the application of numerical methods, such as the finite element method, for more complex cases. The present research presents a numerical analysis of hydraulic fracturing using the extended finite element method (XFEM), in conjunction with the damage constitutive model of Cohesive Zone (MZC). In the extended finite element method the fracture geometry becomes independent of the mesh, allowing the propagation of the fracture through the domain without successive mesh generations as necessary in the conventional finite element method. The computed numerical results were compared with asymptotic analytical solutions in the limit case in which the propagation regime is dominated by the rigidity of the rock with good compatibility. In addition, this study investigates the effects of different parameters of the injection fluid and the fracture propagation characteristics when the interface between different geological layers is inclined, shows dependency between the angle of inclination with the properties of the material and the in-situ stresses.
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ARRIETA, DALMA CAMILA CERRO. "HYDRAULIC FRACTURING IN UNCONVENTIONAL GAS RESERVOIRS: SIMULATION USING DISCRETE ELEMENTS METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33861@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O desenvolvimento e exploração das formações shale gas a nível mundial é relativamente recente, tendo seu início nos Estados Unidos no final da década 1990. A partir dos resultados obtidos com a aplicação do procedimento de fraturamento hidráulico, como método de estimulação, o estudo e avaliação de outros prospectos shale gas em outras regiões do mundo foi estimulado. No entanto, a análise, estudo e caracterização deste tipo de reservatórios são dificultados uma vez que devem ser levados em conta múltiplos fatores relacionados a geologia, mineralogia, petrofísica, geoquímica, entre outros. O fraturamento hidráulico é um processo hidromecânico acoplado com alto grau de dificuldade especialmente em reservatórios shale gas, onde existe a presença de fraturas. Um estudo numérico é conduzido neste trabalho com o objetivo de investigar o comportamento hidromecânico de uma fratura natural durante a injeção de fluido. O software UDEC (Universal Distinct Element Code) baseado no método dos elementos discretos foi empregado no desenvolvimento da modelagem numérica. O UDEC tem a capacidade de modelar o comportamento hidromecânico de uma fratura incluindo os fenômenos de abertura/fechamento das fraturas, cisalhamento e dilatação sob condições de contato ou separação. Nesta investigação numérica foram criados modelos de reservatório com fraturas naturais aleatórias por meio de uma distribuição voronoi visando representar a complexidade da rede de fraturas naturais presentes nas formações shale gas. Os resultados do estudo numérico mostram que o comportamento hidromecânico do sistema é fortemente dependente da variação de parâmetros como tensões in situ, viscosidade do fluido de fraturamento e taxa de injeção de fluido. Portanto, estes resultados proporcionam um melhor entendimento dos mecanismos de fraturamento e resposta da pressão de um tratamento de fraturamento hidráulico em um reservatório de gás não-convencional naturalmente fraturado.
The development and deployment of shale gas formations around the world are relatively recent, starting in the United Stated in the late 1990. From the results obtained with the application of hydraulic fracturing as a method of stimulation, the study and evaluation of other prospects of shale gas in others places in the world was encouraged. However, the analysis, study and characterization of this type of reservoirs are difficult, because it must be taken into account several factors such as geology, mineralogy, petrophysics, geochemistry among others. Hydraulic fracturing is a complicated hydro-mechanical coupled process, with high difficulty degree especially in shale gas reservoir, where natural fractures exist. A numerical study is conducted to investigate the hydromechanical behavior of a natural fracture during fluid injection. UDEC (Universal Distinct Element Code) software based on discrete elements method was employed to numerical modeling development. UDEC has the ability to model the hydro-mechanical behavior of a fracture including phenomena like fracture enlargement, closure, slippage, and dilation under contact or separation condition. In this numerical investigation, numerical reservoir models, with random natural fractures through a distribution voronoi were created aiming to represent the network complexity of natural fractures present in shale gas formations. The numerical study results show that the hydromechanical system behavior is strongly dependent on the parameters variation such as in situ stress, fluid fracturing viscosity and fluid injection rate. Therefore, these results provide a better understanding of fracturing mechanisms and pressure response of a hydraulic fracturing treatment in a non- conventional naturally fractured reservoir.
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Grinnell, S. "The social health and well-being impacts associated with hydraulic fracturing." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/9919/.
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In 2014, the UK Government announced they were, 'going all out for shale gas,' as part of the UKs need to change the energy landscape to focus on security of supply, economic benefits, (reduction of imports), the need to cut carbon emissions and further establish renewable sources. Subsequent licencing to explore for Shale Gas resulted in significant publicised protests concerning environmental issues. Published literature in the form of Case Studies and completed Health Impact Assessments, of which there is a paucity, tend to support these concerns. However, clearly absent from this literature, are the Social Health and Well-Being Impacts (Social Determinants of Health) associated with Hydraulic Fracturing. Data was gathered using an on-line questionnaire which was open for six weeks. The questionnaire included both qualitative and quantitative methods of data collection. Ninety four respondents completed the questionnaire providing over seven hundred pieces of information and comments. Thematic analysis was used to analyse the data sets. The results of this analysis indicate that the threat to the quality of life, environmental concerns and a lack of confidence in the governance of the decision-making process as key factors in the perceptions of the participants. The complexities of these themes were then visually described using causal loop modelling techniques. The research concludes that the public have a very negative and mistrustful perception of Government, Statutory Bodies and the Oil and Gas Industry. Frequently cited social impacts include, stress, anxiety, loss of control and negative impacts on communities including environmental pollution. The implications of this research are that authorities and relevant bodies need to pay far more attention to people and community needs when granting and considering planning consent and licences.
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Nduka, Uzoma C. "Hydraulic Fracturing and Cause-Specific Mortality| A Multicity Comparative Epidemiological Study." Thesis, Walden University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13428593.
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Cause-specific mortality (CSM), among other global health estimates, has garnered prominence in the contemporary public health field. CSM has been associated with several factors, however, research comparing CSM for prefracking versus postfracking periods is sparse. Hydraulic fracturing or fracking is a technique of extracting oil and gas from deep underground. The purpose of this study was to evaluate the difference among mean CSM scores from 1975 through 2015 in the available cities and counties of residence in Colorado and to determine the impact of gender, marital status, county of residence, and city of residence on CSM scores (prefracking period 1975-1977 versus postfracking period 1999-2015) among adults aged 45-70 years. In this retrospective quantitative study, the socioecological model of health was used to analyze 73,251 cases obtained from the Colorado Department of Public Health and Environment. One-way analysis of variance and multiple regression were used to analyze data. Results showed that Denver County had a higher mean CSM score compared to other counties in Colorado. Regression results revealed a significant but weak association between CSM scores and gender, marital status, city of residence, and county of residence. If gender, marital status, and county of residence can be significant predictors of CSM, this information could have social change implications by influencing decisions regarding CSM and fracking.
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Bou, Hamdan Kamel F. "Investigating the role of proppants in hydraulic fracturing of gas shales." Thesis, University of Aberdeen, 2019. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=.
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Migliore, Elizabeth M. "A Case Study of Hydraulic Fracturing in Wetzel County, West Virginia." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1375175273.
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Khattab, Hussein A. "Finite element response modeling of crack geometries induced by hydraulic fracturing /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487261919112032.
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Hawkins, Joanne. "The Legitimisation of hydraulic fracturing regulation: power, prejudice and public participation." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702939.
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Mehta, Neha Ph D. Massachusetts Institute of Technology. "Water management in hydraulic fracturing-a planning and decision optimization platform." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/95585.
Full textAbstract:
Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, Engineering Systems Division, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 73-78).
Recent developments in hydraulic fracturing technology have enabled cost-effective production of unconventional resources, particularly shale gas in the U.S. The process of hydraulic fracturing is water intensive, requiring 4-7 million gallons of water per well, to which a range of chemicals must also be added in order to produce an effective fracturing fluid. Following a fracturing stimulation, anywhere from 10-40% of the injected volume of the water flows back to the surface as a polluted stream of wastewater. This polluted stream of water and the overall inefficient use of water in the hydraulic fracturing process has resulted in a number of negative environmental consequences, specifically surrounding ground and surface water quality and quantity. In considering how to minimize the environmental impacts of hydraulic fracturing, effectively managing water throughout the entire hydraulic fracturing water cycle (water acquisition and disposal) is obviously critical. This dissertation articulates a GIS based optimization model that has been developed to optimize water management planning for unconventional oil and gas production. The model enables a diverse set of stakeholders to develop customized water management strategies based on the geological characteristics and water infrastructure of any given play. The model comprises of a front end GIS interface and a back end optimization engine, designed to minimize the overall system cost of water handling as well as minimizing the overall water footprint of the system. Altogether, it is a powerful decision making tool, which allows the operators to optimize and analyze the temporal and spatial variations in flowback, and produced water management and provide an operationally convenient method to access and share the model analysis. From a regulatory perspective, the modeling framework provides a comprehensive template for a water management plan and could be used as a basis to develop tailored, customized regional solutions that can incorporate the inherent heterogeneity widespread across today's oil and gas plays.
by Neha Mehta.
S.M. in Technology and Policy
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Robertson, Mark Donald. "A statistical continuum approach for mass transport in fractured media." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29740.
Full textAbstract:
The stochastic-continuum model developed by Schwartz and Smith [1988] is a new approach to the traditional continuum methods for solute transport in fractured media. Instead of trying to determine dispersion coefficients and an effective porosity for the hydraulic system, statistics on particle motion (direction, velocity and fracture length) collected from a discretely modeled sub-domain network are used to recreate particle motion in a full-domain continuum model. The discrete sub-domain must be large enough that representative statistics can be collected, yet small enough to be modeled with available resources. Statistics are collected in the discrete sub-domain model as the solute, represented by discrete particles, is moved through the network of fractures. The domain of interest, which is typically too large to be modeled discretely is represented by a continuum distribution of the hydraulic head. A particle tracking method is used to move the solute through the continuum model, sampling from the distributions for direction, velocity and fracture length.
This thesis documents extensions and further testing of the stochastic-continuum two-dimensional model and initial work on a three-dimensional stochastic-continuum model. Testing of the model was done by comparing the mass distribution from the stochastic-continuum model to the mass distribution from the same domain modeled discretely. Analysis of the velocity statistics collected in the two-dimensional model suggested changes in the form of the fitted velocity distribution from a gaussian distribution to a gamma distribution, and the addition of a velocity correlation function. By adding these changes to the statistics collected, an improvement in the match of the spatial mass distribution moments between the stochastic-continuum and discrete models was effected. This extended two-dimensional model is then tested under a wide range of network conditions. The differences in the first spatial moments of the discrete and
stochastic-continuum models were less than 10%, while the differences in the second spatial moments ranged from 6% to 30%. Initial results from the three-dimensional stochastic-continuum model showed that similar statistics to those used in the two-dimensional stochastic-continuum model can be used to recreate the nature of three-dimensional discrete particle motion.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Echavarria, Erika. "Acoustic properties of a 2-D fracture during formation." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1143.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains xiii, 132 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 98).
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Shrestha, Aashish. "Modeling Impact of Hydraulic Fracturing and Climate Change on Stream Low Flows: A Case Study of Muskingum Watershed in Eastern Ohio." Youngstown State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1420797464.
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Sim, Youngjong. "Mechanics of complex hydraulic fractures in the Earth's crust." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-08202004-144611/unrestricted/Sim%5FYoungjong%5F200412%5FPhD.pdf.
Full textAbstract:
Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2005.Puzrin, Alexander M., Committee Member ; Rix, Glenn J., Committee Member ; Mayne, Paul W., Committee Member ; Lowell, Robert P., Committee Member ; Germanovich, Leonid, Committee Chair ; Xu, Wenyue, Committee Member ; Van Dyke, Peter, Committee Member. Vita. Includes bibliographical references.
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Tang, Yin-tong. "Rock stress determination in Hong Kong Island by using hydraulic fracturing method /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36357625.
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Tang, Yin-tong, and 鄧燕棠. "Rock stress determination in Hong Kong Island by using hydraulic fracturing method." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45014322.
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Fletcher, Sarah Marie. "Risk assessment of groundwater contamination from hydraulic fracturing fluid spills in Pennsylvania." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72885.
Full textAbstract:
Thesis (S.M. in Technology and Policy)-- Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 109-115).
Fast-paced growth in natural gas production in the Marcellus Shale has fueled intense debate over the risk of groundwater contamination from hydraulic fracturing and the shale gas extraction process at large. While several notable incidents of groundwater contamination near shale gas wells have been investigated, the exact causes are uncertain and widely disputed. One of the most frequently occurring and widely reported environmental incidents from shale gas development is that of surface spills. Several million gallons of fluid are managed on each well site; significant risk for spill exists at several stages in the extraction process. While surface spills have been primarily analyzed from the perspective of surface water contamination, spills also have the potential to infiltrate groundwater aquifers. This thesis develops a risk assessment framework to analyze the risk of groundwater resource contamination in Pennsylvania from surface spills of hydraulic fracturing fluid. It first identifies the major sources of spills and characterizes the expected frequency and volume distribution of spills from these sources using results from a preliminary expert elicitation. It then develops a stochastic groundwater contaminant transport model to analyze the worst-case potential for groundwater contamination in local water wells. Finally, it discusses the range of risk perception and incentives from a wide-ranging stakeholder base, including industry, communities, environmentalists, and government. This thesis concludes that while the vast majority of shale gas operations do not result in large spills, the worst-case potential for groundwater contamination is high enough to warrant further attention; it also recommends increased inclusion of community stakeholders in both industry and government risk management strategies.
by Sarah Marie Fletcher.
S.M.in Technology and Policy