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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Effects of repetitive, small magnitude earthquakes on groundwater chemistry in Faulkner County, Arkansas

Waggoner, Sarah Elizabeth 01 May 2011 (has links)
The drive to find reliable sources of fuel that follow our green concerns and reduce our dependence on foreign sources of fossil fuels has pushed exploration and recovery of natural gas from within the United States to a top priority. Earthquakes generated from the use of hydraulic fracturing techniques and/or use of high pressure injection wells are occurring at an alarming rate due to increases in hydrocarbon exploration and recovery. While the link between earthquakes and hydrocarbon production is still uncertain, earthquake induced changes to groundwater chemistry are clear. Yet it has not been determined if repetitive, smaller earthquakes, i.e. earthquakes with magnitudes less than Mw<4.5, can result in similar disturbances to water chemistry as the more significant events have been proven to cause. Two known earthquake swarms, each having repetitive, small earthquake events, occurred in an intraplate setting in Faulkner County, Arkansas. Testing for groundwater chemical changes related to the timing of earthquake events and total energy released show that small earthquakes indeed create changes to groundwater chemistry most probably due to fluid intrusion from deep, chloride, calcium, and magnesium rich waters. The reduction of the United States dependence on foreign sources or finding green sources of fuel should not be the only mitigating factor for our decisions concerning our natural resources.
112

Avaliação da potencialidade do shale gas no Brasil a partir da experiência dos Estados Unidos

Martins, Rhodiney Vaz January 2016 (has links)
Orientador: Prof. Dr. Igor Fuser / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2016. / Nos dias atuais a energia tem sido prioridade de vários governos pelo mundo, e vem despertando o interesse de grandes companhias. A energia tem um papel fundamental na sociedade moderna, onde a cada ano o consumo aumenta. A descoberta de enormes reservas de gás não convencional, ou conhecido também como shale gas, vem gerando grande expectativa no mercado mundial de energia. Os EUA têm a maior reserva mundial de shale gas, e são os pioneiros na sua exploração e produção. O Brasil possui a decima maior reserva mundial de shale gas. A sua reserva de shale gas equivale a quinze vezes as reservas de gás convencional do país em 2015 (MME, 2015). Devido a isso pode-se considerar as reservas brasileiras expressivas, o que vem despertando o interesse do país por suas reservas de shale gas. Esta dissertação tem como objetivo analisar o potencial do Brasil para a exploração e produção doshale gas. Para isso, foram consideradas variáveis do Brasil e EUA, como: o estado da arte do mercado regulatório, do domínio tecnológico, qualificação da mão de obra, conhecimento geológico, estrutura de preços, propriedade do solo e subsolo, e por fim as questões ambientais. Procurando assim fazer um paralelo entre essas variáveis dos dois países, verificando se o crescimento da exploração do shale gas americano pode ser repetido no Brasil. Além dessa comparação dos cenários energéticos, foi também levantado depoimentos de especialistas do setor de gás natural do Brasil, por meio de entrevista, contribuindo assim para um debate dos rumos da política energética brasileira. O resultado desta pesquisa mostrou que o Brasil não necessita explorar o shale gas neste momento e ainda não possui um mercado regulatório favorável e mercado interno desenvolvido para o desenvolvimento dos recursos de shale gas. Considerando tanto o aspecto econômico como o ambiental, a conclusão deste trabalho foi de que o Brasil não deve levar adiante a exploração do shale gas, dentro de um tempo previsível. / In the present day energy has been a priority of many Governments around the world, arousing the interest of big companies. Energy has a key role in modern society, where each year the consumption increases. The discovery of vast reserves of unconventional gas, or also known as shale gas comes generating great expectations in the global energy market. The us has the largest world reserve of shale gas, and are pioneers in their exploration and production. The Brazil has the world's largest reserve of decima shale gas. Your reservation of shale gas is equivalent to 15 times the conventional gas reserves in the country in 2015 (MME, 2015). Because of this you can consider the Brazilian reserves, expressive arousing the interest of the country for its reserves of shale gas. This dissertation aims to analyze the potential of Brazil for the exploration and production of shale gas. For this, the variables were considered Brazil and USA, as: the State of the art market's regulatory, technological domain, qualification of the workforce, geological knowledge, price structure, property of the soil and subsoil, and finally environmental issues. Looking for how to make a parallel between these variables of the two countries, noting the growth of shale gas American can be repeated in Brazil. In addition to this comparison of energy scenarios, was also lifted testimonials from industry experts, Brazil's natural gas through the interview, thus contributing to a discussion of the direction of the Brazilian energy policy. The result of this research showed that Brazil does not need to explore shale gas right now and still does not have a favourable regulatory and market internal market developed for resource development of shale gas. Considering both the economic aspect as the environmental, the conclusion of this work was that Brazil should not carry out the exploitation of shale gas, within a predictable time.
113

Simulação de fraturamento hidráulico usando elementos finitos de elevada razão de aspecto com acoplamento hidromecânico /

Cleto, Pedro Rogério. January 2016 (has links)
Orientador: Osvaldo Luís Manzoli / Banca: Flavia de Oliveira Lima Falcão / Banca: Leonardo José do Nascimento Guimarães / Resumo: A técnica de fraturamento hidráulico é amplamente utilizada na indústria petrolífera para aumentar a permeabilidade da rocha-reservatório numa região próxima ao poço e permitir a extração, e consequente produção, de hidrocarbonetos armazenados em seus poros. Primeiramente a rocha é perfurada criando-se um poço e então injeta-se fluido a uma pressão suficientemente alta para fraturar a rocha. A injeção contínua de fluido permite que as fraturas se propaguem pelo reservatório, formando assim canais de alta permeabilidade. A modelagem e simulação computacional de fraturamento hidráulico são complexas em função da física envolvida no processo. O presente trabalho objetiva o estudo da formação e propagação de fraturas induzidas hidraulicamente em meios rochosos de baixa permeabilidade e também tem o propósito de verificar se a metodologia adotada é capaz de reproduzir características apresentadas num processo de fraturamento hidráulico, como a pressão necessária para causar a ruptura da rocha. Para tal, apresenta-se a técnica de fragmentação da malha utilizando elementos finitos de elevada razão de aspecto (ou elementos de interface) para representar a fratura, aos quais são atribuídas relações constitutivas baseadas na mecânica do dano. Além disso, os elementos de interface também possuem um acoplamento hidromecânico capaz de representar o canal de alta permeabilidade devido à ocorrência da fratura. Os resultados obtidos mostraram que os elementos de interface asso... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The hydraulic fracturing technique is widely used to increase the permeability of reservoirs in the vicinity of the well and to allow the extraction and subsequent production of hydrocarbons trapped in its pores. Firstly, the rock is drilled, creating a well and then a fluid is injected at a sufficiently high pressure to fracture the rock. The continuous fluid injection allows the fractures to propagate through the reservoir, thereby forming some high permeability paths. The computer modeling and simulation of hydraulic fracturing are complex due to the physics involved in the process. This work aims to study the formation and propagation of hydraulically induced fractures in rocky media with low permeability and also aims to verify if the adopted methodology is able to reproduce the characteristics presented in a hydraulic fracturing process, as for instance, the required pressure to cause the breakdown of the rock. For this purpose, it is presented the mesh fragmentation technique using finite elements with a high aspect ratio (or interface elements) to represent the fracture, which are assigned constitutive relations based on damage mechanics. Besides, the interface elements also have a hydromechanical coupling which is able to represent the high permeability path due to the fracture. The results showed that the interface elements associated with the mesh fragmentation technique were able to represent both the formation and the propagation of hydraulically induc... (Complete abstract click electronic access below) / Mestre
114

[en] EVALUATING CHARACTERISTICS OF STATIC AND DYNAMIC FILTRATION OF A FLUID USED IN HYDRAULIC FRACTURING AT ROOM TEMPERATURE / [pt] AVALIAÇÃO DAS CARACTERÍSTICAS DE FILTRAÇÃO ESTÁTICA E DINÂMICA DE UM FLUIDO USADO EM FRATURAMENTO HIDRÁULICO À TEMPERATURA AMBIENTE

PAULO ROBERTO DA FONSECA SANTOS 12 March 2018 (has links)
[pt] Este trabalho teve como objetivo estudar as características de filtração estática e dinâmica de um fluido usado em fraturamento hidráulico à temperatura ambiente. Para sua realização foi projetado, desenvolvido e qualificado metrologicamente um simulador que permitisse efetuar testes de filtração estática e dinâmica. Foram realizadas filtrações com um fluido newtoniano (água) e um não newtoniano (HPGUAR-BO lbm/1000gal). / [en] This research intended to study the characteristcs of dynamic and static leakoff of a fluid in hydraulic fracturing at room temperature. A test apparatus was designed, constructed and metrologically qualified in order to carry out dynamic and stactic leakoff test. Leakoffs with a Newtonian fluid (water) and with a non-Newtonian one (HPGUAR-BO lbm/1000 gal) were performed.
115

Distinct element modeling for fundamental rock fracturing and application to hydraulic fracturing / 粒状体個別要素法による岩石破壊現象の基礎的検討および水圧破砕の破壊過程に関する研究

Shimizu, Hiroyuki 23 March 2010 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15338号 / 工博第3217号 / 新制||工||1484(附属図書館) / 27816 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 石田 毅, 教授 松岡 俊文, 教授 三ケ田 均 / 学位規則第4条第1項該当
116

Assessing The Probability Of Fluid Migration Caused By Hydraulic Fracturing; And Investigating Flow And Transport In Porous Media Using Mri

Montague, James 01 January 2017 (has links)
Hydraulic fracturing is used to extract oil and natural gas from low permeability formations. The potential of fluids migrating from depth through adjacent wellbores and through the production wellbore was investigated using statistical modeling and predic-tive classifiers. The probability of a hydraulic fracturing well becoming hydraulically connected to an adjacent well in the Marcellus shale of New York was determined to be between 0.00% and 3.45% at the time of the study. This means that the chance of an in-duced fracture from hydraulic fracturing intersecting an existing well is highly dependent on the area of increased permeability caused by fracturing. The chance of intersecting an existing well does not mean that fluid will flow upwards; for upward migration to occur, a pathway must exist and a pressure gradient is required to drive flow, with the exception of gas flow caused by buoyancy. Predictive classifiers were employed on a dataset of wells in Alberta Canada to identify well characteristics most associated to fluid migration along the production well. The models, specifically a random forest, were able to identify pathways better than random guessing with 78% of wells in the data set identified cor-rectly. Magnetic resonance imaging (MRI) was used to visualize and quantify contami-nant transport in a soil column using a full body scanner. T1 quantification was used to determine the concentration of a contaminant surrogate in the form of Magnevist, an MRI contrast agent. Imaging showed a strong impact from density driven convection when the density difference between the two fluids was small (0.3%). MRI also identified a buildup of contrast agent concentration at the interface between a low permeability ground silica and higher permeability AFS 50-70 testing sand when density driven con-vection was eliminated.
117

Investigação experimental sobre a geração, visualização e avaliação da condutividade de fraturas ácidas em carbonatos microbiais / Experimental investigation of the building, visualization and evaluation of acid fracture conductivity on microbial carbonates

Neumann, Luís Fernando 07 August 2011 (has links)
Orientadores: Jose Luiz Antunes de Oliveira e Sousa, Paulo Dore Fernandes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-18T16:09:28Z (GMT). No. of bitstreams: 1 Neumann_LuisFernando_M.pdf: 28066529 bytes, checksum: 854d0f8d8feee96cc1c3e1adff5373dc (MD5) Previous issue date: 2011 / Resumo: O sucesso da estimulação por fraturamento hidráulico ou ácido é dependente da geração de condutividade. No fraturamento hidráulico sustentado, a condutividade é gerada pela introdução de uma quantidade significativa de um agente de sustentação granular e praticamente esférico. No fraturamento ácido, a condutividade é gerada por irregularidades reveladas devido à reação desigual do ácido em cada uma das faces da fratura naturalmente rugosa e da resistência destas mesmas irregularidades para suportar as tensões que atuam após o fechamento da fratura. A baixa resistência das irregularidades leva ao colapso e cicatrização da fratura ácida com a perda total da condutividade. Esta dissertação investiga a viabilidade da estimulação por fraturamento ácido em carbonatos microbiais rasos e profundos. Ensaios de laboratório em escala reduzida foram projetados para verificar se a condutividade de uma fratura induzida por reação química da rocha reservatório com um ácido forte pode ser mantida frente às elevadas tensões normais efetivas que agirão na fase de explotação do poço. A dissertação ainda investiga se o emprego de uma pequena quantidade de agente de sustentação é capaz de dividir os esforços aplicados sobre as irregularidades de uma fratura ácida e manter a condutividade por maiores períodos de tempo. As superfícies que imitam fraturas ácidas são criadas pelo ataque ácido em corpos de prova em condições de laboratório que reproduzem em escala aquelas observadas em um fraturamento ácido real. Imagens digitais são utilizadas para medir a rugosidade das fraturas ácidas e o consumo de rocha carbonática pelo ácido na face do corpo de prova. A resistência das irregularidades é medida indiretamente pelo decréscimo da condutividade da fratura ácida frente a tensões de confinamento crescentes. O efeito ou não da adição de agente de sustentação é medido pela comparação dos parâmetros da correlação empírica desenvolvida por Nierode e Kruk / Abstract: A well succeeded stimulation by hydraulic or acid fracturing is related to conductivity creation. In a hydraulic fracturing, the conductivity is created by means of introducing a significant amount of a propping agent. In an acid fracturing, the conductivity is related to the creation of asperities due to uneven acid reaction on each naturally rougher fracture side and the asperities strength to withstand high stresses that start to act just after fracture closure. Low asperities strength leads to collapse of acid fracture and fracture healing with total conductivity loss. The dissertation investigates the feasibility of acid fracturing stimulation in shallow and deep microbial carbonates. Laboratory tests were designed to verify if the acid fracture conductivity induced by chemical reaction of reservoir rock with a strong acid could be kept when facing the high effective normal stress that is expected in exploitation phase. The dissertation still investigates whether the use of a small amount of proppant is able to share the tension that acts on asperities and maintain the acid facture conductivity for longer periods. The surfaces that mimic acid fractures are created by acid etching specimens in laboratory conditions reduced in scale from those observed in an actual acid fracturing job. Digital images are used to measure fracture roughness and rock consumption by acid on the specimen face. The asperities strength is indirectly measured from acid conductivity decrease under increased confinement tension. The effect of adding or not adding propping agent is accomplished comparing empirical parameters from Nierode and Kruk correlation / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo
118

Aproximação numérica de propagação de fraturas hidráulicas em domínio bidimensional com elastoplasticidade / Numerical approximation of hydraulic fracturing in bidimensional domain with elastoplasticity

Shauer, Nathan, 1989- 26 August 2018 (has links)
Orientador: Philippe Remy Bernard Devloo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T15:50:44Z (GMT). No. of bitstreams: 1 Shauer_Nathan_M.pdf: 4772079 bytes, checksum: c339b53fa640108ef53c5f66523a128c (MD5) Previous issue date: 2015 / Resumo: Fraturamento Hidráulico é o processo pelo qual uma fratura se propaga através da injeção de um fluido pressurizado em seu interior. É muito utilizado na indústria de petróleo, pois cria uma zona de alta condutividade, possibilitando aumento nas taxas de injeção ou produção. Esse trabalho consiste na implementação numérica, no ambiente orientado a objetos NeoPZ, de uma fratura propagando hidraulicamente em um domínio bidimensional pelo método dos elementos finitos. Os fenômenos envolvidos considerados são a resposta mecânica do reservatório utilizando a relação tensão deformação elastoplástica, junto com escoamento entre placas planas no interior da fratura, incluindo o efeito de leak-off dado pelo modelo de Carter. Os critérios de plastificação utilizados são o de Mohr-Coulomb, que é usado para comparar os resultados com os de Papanastasiou, P. [1], e o de Sandler-DiMaggio, que é referenciado por Santos, E. S. [2] como sendo um bom critério para modelar a relação constitutiva de formações de óleo e gás. São utilizados conceitos de c++ orientação a objetos, materiais coesivos para critério de propagação, acoplamento completo de fenômenos e utilização de espaços reduzidos. As rotinas implementadas são verificadas de acordo com equações analíticas e observando que a conservação de massa é satisfeita. Com esse estudo confrontam-se os resultados obtidos pela abordagem da Elasticidade Linear usualmente utilizada, percebendo que a simulação de fraturamento hidráulico com elastoplasticidade, devido a plastificação da ponta, gera fraturas com menores comprimentos e maiores aberturas para um mesmo volume de injeção como observado por Papanastasiou, P. et al. [1, 3, 4] / Abstract: Hydraulic Fracturing is the process in which a fracture propagates through the injection of a pressurized fluid in its interior. It is widely used in the oil industry due to the high conductivity zone it creates, which provides high rates of both injection and production. This work consists in the numerical implementation, in the object oriented environment NeoPZ, of a fracture hydraulically propagating in a two dimensional elastoplastic medium using the Finite Elements method. The involved phenomena considered are the mechanical response of the reservoir, using the elastoplastic stress-strain relationship, along with the flow between plane plates within the fracture and considering the leak-off on the walls of the fracture using the Carter model. The elastoplastic criteria used are the Mohr-Coulomb criteria, which is used to compare results with the ones from Papanastasiou, P. [1], and the Sandler-DiMaggio criteria, which is referenced by Santos, E. S. [2] as a good criteria to model the constitutive relation of oil and gas formations. Some of the concepts used in this work are c++ object oriented language, cohesive zone for fracture propagation, fully coupling of the involved phenomena, and use of reduced spaces. The routines implemented in this work are verified according to analytical equations and verifying that the conservation law is satisfied. In this study the results obtained are compared with the Linear Elasticity approach, which is commonly used, realizing that simulation of hydraulic fracturing using elastoplastic constitutive laws, due to the yielding of the tip, generates smaller fracture lengths and larger apertures for the same injection volume as observed by Papanastasiou, P. et al. [1, 3, 4] / Mestrado / Estruturas e Geotécnica / Mestre em Engenharia Civil
119

Community based air quality monitoring near proppant sand facilities

Grant, Ryan James 01 July 2015 (has links)
Silica sand is used in the hydraulic fracturing process as a proppant—a material that holds open fissures in a rock formation to allow oil and gas to escape. Due to the increased demand for proppant sand, numerous sand mining and processing facilities have been constructed in the vicinity of small communities. Silica sand contains crystalline silica, which can cause chronic health problems such as silicosis. This study monitored airborne particulate matter at residences within 800 m from the facilities property line, with active mining, processing, and/or transport. Real-time particulate air monitoring with automated acquisition of explanatory variables: sound and motion to detect transportation; and wind speed and direction to attribute measured PM concentrations to specific sources. The highest daily mean concentrations were 37.3 μg/m3 for PM10 and 14.5 μg/m3 for PM2.5, both of which are well below the EPA National Ambient Air Quality Standards. Using conditional probability plots of PM relative to wind direction elevated short-term (20 second) peak concentrations were more likely to occur when the wind was blowing from the sand facility. These peak concentrations occurred infrequently, ranging from 0% to 3% of the sampling time. This study did not measure crystalline silica specifically, but low PM concentrations were observed so crystalline silica is expected to be low. Since PM concentrations were low near the facilities, it can be concluded that these facilities do not increase airborne particulate matter to hazardous concentrations that could cause chronic health conditions.
120

What Drives the Fracking Boom Crime Relationship? A Fixed-Effects Analysis of Crime during the Pennsylvania Fracking Boom

Batista-Lin, Webster 18 March 2022 (has links)
The rapid expansion of hydraulic fracturing(fracking) over the past two decades has led to an increasing interest in the relationship between natural resource booms and crime. Since the onset of the fracking boom, numerous anecdotal accounts and an increasing body of empirical studies have suggested that fracking has a significant, positive impact on crime. However, the mechanisms behind this relationship are poorly understood. This study uses a high-resolution dataset and a unique, fixed-effects approach to decompose the effect that fracking has on crime into increases due to the introduction of new wells and increases due to the presence of existing wells. The findings suggest that new wells have a different impact on crime than existing wells. Specifically, new wells result in greater increases in violent crimes. These results may indicate that the relationship between fracking and crime is largely driven by the influx of non-local, transient, fracking labor.

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