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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.
11

Avaliação da condutividade hidráulica e da resistência ao cisalhamento de misturas solo-bentonita: estudo de caso de um aterro sanitário localizado em Rio Grande (RS) / Evaluation of hydraulic conductivity and shear strength of soil-bentonite mixtures: a case study of a landfill located in Rio Grande (RS)

Camargo, Karina Retzlaff 15 October 2012 (has links)
A utilização do solo natural compactado com bentonita empregado em camadas impermeáveis para retenção de contaminantes é bastante usual para aterros sanitários. Neste trabalho são apresentados resultados de ensaios condutividade hidráulica e de resistência ao cisalhamento, realizados em equipamentos triaxiais. Além do solo natural, foram utilizadas misturas solo-bentonita nos teores de 2%, 4% e 6%. O solo arenoso ensaiado é encontrado na Planície Costeira Sul do Estado do Rio Grande do Sul. Os valores de condutividade hidráulica diminuiram tanto com o acréscimo do teor de bentonita, quanto com o aumento da tensão de confinamento. A condutividade hidráulica do solo apresentou uma redução de três ordens de grandeza quando este foi compactado com 6% de bentonita (de \'10 POT.-7\' para \'10 POT.-10\' m/s). Em relação a resistência ao cisalhamento do material, constatou-se que com o acréscimo do teor bentonita de 0 para 6%, a coesão efetiva aumentou (de 2,3 para 12,8 kPa) e o ângulo de atrito efetivo diminuiu (de 22,7º pra 14,0º). / Compacted soil-bentonite mixtures used as impermeable layers for retention of contaminants is quite usual in landfills. This paper presents the results of hydraulic conductivity and shear strength tests conducted in a triaxial apparatus. Natural soil, and soil-bentonite mixtures at 2%, 4% and 6% concentrations were tested. The sandy soil tested is found in the Southern Coastal Plain of Rio Grande do Sul. The hydraulic conductivity decreased with both the increase of bentonite content and increase of confining stress. Compared to natural soil, the hydraulic conductivity of compacted soil-bentonite mixtures at 6% content decreased by three orders of magnitude (from \'10 POT.-7\' to \'10 POT.-10\' m/s). Regarding the material shear strength, it was found that when the natural soil is compared to compacted soil-bentonite mixtures at 6% content, the effective cohesion increased (from 2.3 to 12.8 kPa) and the effective friction angle decreased (from 22. 7º to 14.0º).
12

Performance and Operation of Partial Infiltration Permeable Pavement Systems in the Ontario Climate

Drake, Jennifer Anne Pauline 09 July 2013 (has links)
Partial-infiltration permeable pavement (PP) systems provide environmental benefits by increasing infiltration, attenuating storm flows and improving stormwater quality. This thesis focuses on the performance and operation of partial-infiltration PP systems over low permeability soil in Ontario. Three PP, AquaPave®, Eco-Optiloc® and Hydromedia® Pervious Concrete were monitored over two years and their performance was evaluated relative to an impermeable Asphalt control. Field data was collected from the Kortright PP pilot parking lot in Vaughan, Ontario. Through the use of restrictor valves on underdrains the PP systems were shown to provide substantial hydrologic benefits by eliminating stormwater outflow for rain events less than 7mm, reducing peak flows by 91% and reducing total stormwater volume by 43%. Stormwater quality was analyzed for winter and non-winter seasons. The PP were shown to greatly reduce the concentration and total loading of suspended solids, nutrients, hydrocarbons and most heavy metals. Some water quality data, such as pH, K, or Sr levels, indicate that the quality of PP effluent will change as the system ages. Study of PP sample boxes at the University of Guelph highlighted the role that construction materials have on effluent quality and showed that pollutants introduced by the pavement and aggregate are almost entirely in a dissolved form and decline very rapidly after a season of exposure to rainfall. Benefits to water quality were sustained during winter months. The partial-infiltration PP systems were shown to provide buffering of Na and Cl concentrations. Small and large-scale maintenance practices for PP systems were investigated. Small-sized equipment testing found that vacuum cleaning and pressure-washing have good potential to improve infiltration capacity. Testing of full-sized streetsweeping trucks demonstrated that permeability can be partially restored on PICP by suction-based sweeping. Vacuum-sweeping was beneficial on a PC pavement which had experienced large permeability losses. Results of this study indicate that partial-infiltration PP systems can be effective measures for maintaining or restoring infiltration functions on parking lots and other low volume traffic areas, even in areas with low permeability soils.
13

Sedimentology, ichnology, and resource characteristics of the low-permeability Alderson Member, Hatton Gas Pool, southwest Saskatchewan, Canada

Lemiski, Ryan Thomas Unknown Date
No description available.
14

Sedimentology, ichnology, and resource characteristics of the low-permeability Alderson Member, Hatton Gas Pool, southwest Saskatchewan, Canada

Lemiski, Ryan Thomas 06 1900 (has links)
The Upper Cretaceous Alderson Member is a prolific gas (biogenic) producer in western Canada. In the Hatton Gas Pool area (southwest Saskatchewan), Alderson Member strata from ten drill-cores have been examined and classified based on sedimentological and ichnological character. Core analysis has determined that Alderson Member deposits comprise thick intervals of pervasively bioturbated strata. Using spot-minipermeametry and high-pressure mercury injection porosimetry methods, the influence of pervasively bioturbated intervals on the overall resource potential of Alderson Member strata is evaluated. Results from permeability and porosity testing demonstrate that pervasively bioturbated rock fabrics appear to locally enhance the overall storage and vertical transmission of gas from Alderson Member reservoirs.
15

Investigations of Partial Gas Saturation on Diffusion in Low-permeability Sedimentary Rocks

Nunn, Jacob 06 November 2018 (has links)
The effect of partially saturated conditions on aqueous diffusion was investigated on the Upper Ordovician Queenston Formation shale from the Michigan Basin of southwest Ontario, Canada. Effective diffusion coefficients (De) were determined for iodide tracer on duplicate cm-scale samples from a core segment. Partially saturated conditions were created with a new gas-ingrowth method that takes advantage of the variability of N2 solubility with pressure. The method is designed to create partially saturated pores, quantify the level of partial gas/brine saturation within the tracer-accessible pore space, and measure De under fully porewater-saturated and partially gas-saturated conditions for the same sample. X-ray radiography is used with an iodide tracer for quantifying the degree of partial saturation and measuring De. The saturated De values range from 2.8 x 10-12 to 3.1 x 10-12 m2/s. Following generation of a gas phase in the pores (average gas saturations of 4 to 6.7 %), De values decrease by 20 to 22 % relative to the porewater-saturated condition, indicating that the tortuosity factor (ratio of constrictivity to tortuosity) is sensitive to saturation. Suggesting that a small volume of the pore fraction is responsible for majority of the transport. The gas-ingrowth method was successful for generating partial gas saturation, but the distribution of the gas phase is non-uniform, with relatively high gas saturations near boundaries and lower saturations in the interior of the samples.
16

An?lise da recupera??o em reservat?rio de g?s com baixa permeabilidade (TIGHT GAS) atrav?s do fraturamento hidr?ulico

Bessa Junior, Francisco de Paiva 28 February 2014 (has links)
Made available in DSpace on 2014-12-17T14:08:57Z (GMT). No. of bitstreams: 1 FranciscoPBJ_DISSERT.pdf: 5706323 bytes, checksum: 7e213d2df30615621d9d118318bdfa95 (MD5) Previous issue date: 2014-02-28 / Petr?leo Brasileiro SA - PETROBRAS / With the increasing of energetic consumption in the worldwile, conventional reservoirs, known by their easy exploration and exploitation, are not being enough to satisfy this demand, what has made necessary exploring unconventional reservoirs. This kind of exploration demands developing more advanced technologies to make possible to exploit those hydrocarbons. Tight gas is an example of this kind of unconventional reservoir. It refers to sandstone fields with low porosity, around 8%, and permeabilities between 0.1 and 0.0001 mD, which accumulates considerable amounts of natural gas. That natural gas can only be extracted by applying hydraulic fracturing, aiming at stimulating the reservoir, by creating a preferential way through the reservoir to the well, changing and making easier the flow of fluids, thus increasing the productivity of those reservoirs. Therefore, the objective of this thesis is analyzing the recovery factor of a reservoir by applying hydraulic fracturing. All the studies were performed through simulations using the IMEX software, by CMG (Computer Modelling Group), in it 2012.10 version / Com o crescimento do consumo energ?tico em todo o mundo, os reservat?rios convencionais, chamados de reservat?rios de f?cil explora??o e produ??o n?o est?o atendendo ? demanda energ?tica mundial, fazendo-se necess?rio a explora??o de reservas n?o convencionais. Esse tipo de explora??o exige o desenvolvimento de tecnologias mais avan?adas para a sua explota??o. Como exemplo dessas reservas, temos os reservat?rios do tipo Tight Gas, onde referem-se aos campos de arenito com baixa porosidade, na faixa de 8%, e permeabilidade na faixa entre 0,1 mD e 0,0001 mD, que acumulam consider?veis reservas de g?s natural, podendo apresentar viabilidade econ?mica para explota??o. O g?s natural nesse tipo de reservat?rio s? pode ser extra?do a partir da aplica??o da t?cnica de faturamento hidr?ulico, que tem por finalidade estimular o po?o, criando um canal de alta condutividade entre o po?o e o reservat?rio alterando e facilitando o fluxo de fluidos, aumentando assim a produtividade do reservat?rio. Assim, o objetivo desse trabalho ? analisar o fator de recupera??o do reservat?rio com a aplica??o do fraturamento hidr?ulico. Os estudos foram realizados atrav?s de simula??es concretizadas no m?dulo IMEX do programa da CMG (Computer Modelling Group), vers?o 2012.10
17

Avaliação da condutividade hidráulica e da resistência ao cisalhamento de misturas solo-bentonita: estudo de caso de um aterro sanitário localizado em Rio Grande (RS) / Evaluation of hydraulic conductivity and shear strength of soil-bentonite mixtures: a case study of a landfill located in Rio Grande (RS)

Karina Retzlaff Camargo 15 October 2012 (has links)
A utilização do solo natural compactado com bentonita empregado em camadas impermeáveis para retenção de contaminantes é bastante usual para aterros sanitários. Neste trabalho são apresentados resultados de ensaios condutividade hidráulica e de resistência ao cisalhamento, realizados em equipamentos triaxiais. Além do solo natural, foram utilizadas misturas solo-bentonita nos teores de 2%, 4% e 6%. O solo arenoso ensaiado é encontrado na Planície Costeira Sul do Estado do Rio Grande do Sul. Os valores de condutividade hidráulica diminuiram tanto com o acréscimo do teor de bentonita, quanto com o aumento da tensão de confinamento. A condutividade hidráulica do solo apresentou uma redução de três ordens de grandeza quando este foi compactado com 6% de bentonita (de \'10 POT.-7\' para \'10 POT.-10\' m/s). Em relação a resistência ao cisalhamento do material, constatou-se que com o acréscimo do teor bentonita de 0 para 6%, a coesão efetiva aumentou (de 2,3 para 12,8 kPa) e o ângulo de atrito efetivo diminuiu (de 22,7º pra 14,0º). / Compacted soil-bentonite mixtures used as impermeable layers for retention of contaminants is quite usual in landfills. This paper presents the results of hydraulic conductivity and shear strength tests conducted in a triaxial apparatus. Natural soil, and soil-bentonite mixtures at 2%, 4% and 6% concentrations were tested. The sandy soil tested is found in the Southern Coastal Plain of Rio Grande do Sul. The hydraulic conductivity decreased with both the increase of bentonite content and increase of confining stress. Compared to natural soil, the hydraulic conductivity of compacted soil-bentonite mixtures at 6% content decreased by three orders of magnitude (from \'10 POT.-7\' to \'10 POT.-10\' m/s). Regarding the material shear strength, it was found that when the natural soil is compared to compacted soil-bentonite mixtures at 6% content, the effective cohesion increased (from 2.3 to 12.8 kPa) and the effective friction angle decreased (from 22. 7º to 14.0º).
18

Comportement hydromécanique des argilites du Callovo-Oxfordien lors de cycles de désaturation-resaturation / Hydromechanical behaviour of the Callovo-Oxfordian claystones during drainage-imbibiton cycles

Guillon, Théophile 08 December 2011 (has links)
Les propriétés des argilites du Callovo-Oxfordien les désignent comme une barrière naturelle sûre pour le stockage de déchets radioactifs. Afin d’optimiser la prédiction de leur comportement, leur réponse à diverses sollicitations à court et long termes est étudiée. Notamment, lors de la phase d’exploitation, l’air ventilé dans les galeries n’est pas à l’équilibre hydrique avec la roche et peut perturber ses propriétés hydromécaniques (HM). Il semble alors essentiel de caractériser la réponse HM de la roche à des sollicitations hydriques.La démarche adoptée consiste à proposer un modèle physique adéquat, sur la base d’essais au laboratoire. L’essai de séchage est retenu puisqu’il permet d’étudier la réponse des échantillons en conditions non-saturées. A partir des résultats HM, un modèle élastique 2D isotrope est proposé, puis est élevé à la 3D avec un module de Young isotrope transverse. Ensuite, les données expérimentales servent à estimer certains paramètres poroélastiques et de transfert du modèle. Cette étape est accomplie par procédure inverse (minimisation de l’erreur mesures-calculs). Enfin, une modélisation 2D du comportement in situ est proposée, et compare les prédictions de modèles plastique isotrope et élastique isotrope transverse.Les simulations d’essais au laboratoire reproduisent assez bien les données expérimentales. Pour la modélisation in situ, une bonne corrélation est obtenue entre les prédictions et les mesures, et ce sans ajustement préalable des paramètres. Toutefois, le modèle souligne une influence limitée de la plasticité à l’échelle du laboratoire, alors que les phénomènes dissipatifs sont marqués in situ. Les modélisations 3D au laboratoire ne donnent pas de résultats plus fins qu’en 2D, mais reproduisent plus de données expérimentales (variations de masse, déformations axiales et latérales). De plus, injecter plusieurs types de données dans la formulation inverse permet d’améliorer la précision de l’algorithme. Par ailleurs, une meilleure stabilité de l’algorithme est obtenue en adoptant une convergence en deux étapes (simplex, puis méthode de type gradient). Les estimations numériques des paramètres corroborent les mesures expérimentales obtenues par ailleurs. / The Callovo-Oxfordian claystones’ properties make them reliable as a geological barrier for the confinement of radioactive wastes. In order to optimally predict their behavior, how they respond to various short and long terms loadings has to be studied. Particularly during the exploitation phase, air is continuously ventilated throughout the galleries. The climatic properties of this air are not balanced with those of the rock, and may perturb its hydromechanical (HM) attributes. Thus, assessing the HM response of the rock under hydric loading seems to be a priority.This dissertation begins with laboratory tests to propose an appropriate physical model. Drying tests were studied as they focus on the HM response of samples undergoing hydric loadings. A first 2D isotropic model is proposed, and then enhanced to 3D by considering a transversely isotropic Young modulus. Secondly, experimental results provide relevant data to estimate poroelastic and transport parameters involved in the model. Estimation is achieved according to an inverse procedure, which minimizes the error between measurements and model predictions. Finally, a real-size test is simulated using 2D models: an isotropic plastic one and a transversely isotropic elastic one.Model predictions reproduce well the laboratory tests data. When simulating the in situ behavior, a rather good agreement is obtained between the numerical and experimental results (although using the parameters estimated at the laboratory scale). However, the model highlights a limited influence of plasticity in the laboratory tests, while dissipative phenomena obviously occur in situ. 3D laboratory simulations do not improve the precision of 2D results, but reproduce more experimental data (mass variations, axial and lateral strains). Moreover, the inversion process is more efficient when ran over various kinds of data. Furthermore, stability of the algorithm is improved when adopting a two-phase convergence (simplex, followed by a gradient-like method). Numerical estimates of the parameters are in agreement with the direct experimental measurements obtained through other tests.
19

Pressure Normalization of Production Rates Improves Forecasting Results

Lacayo Ortiz, Juan Manuel 16 December 2013 (has links)
New decline curve models have been developed to overcome the boundary-dominated flow assumption of the basic Arps’ models, which restricts their application in ultra-low permeability reservoirs exhibiting long-duration transient flow regimes. However, these new decline curve analysis (DCA) methods are still based only on production rate data, relying on the assumption of stable flowing pressure. Since this stabilized state is not reached rapidly in most cases, the applicability of these methods and the reliability of their solutions may be compromised. In addition, production performance predictions cannot be disassociated from the existing operation constraints under which production history was developed. On the other hand, DCA is often carried out without a proper identification of flow regimes. The arbitrary application of DCA models regardless of existing flow regimes may produce unrealistic production forecasts, because these models have been designed assuming specific flow regimes. The main purpose of this study was to evaluate the possible benefits provided by including flowing pressures in production decline analysis. As a result, it have been demonstrated that decline curve analysis based on pressure-normalized rates can be used as a reliable production forecasting technique suited to interpret unconventional wells in specific situations such as unstable operating conditions, limited availability of production data (short production history) and high-pressure, rate-restricted wells. In addition, pressure-normalized DCA techniques proved to have the special ability of dissociating the estimation of future production performance from the existing operation constraints under which production history was developed. On the other hand, it was also observed than more consistent and representative flow regime interpretations may be obtained as diagnostic plots are improved by including MBT, pseudovariables (for gas wells) and pressure-normalized rates. This means that misinterpretations may occur if diagnostic plots are not applied correctly. In general, an improved forecasting ability implies greater accuracy in the production performance forecasts and more reliable reserve estimations. The petroleum industry may become more confident in reserves estimates, which are the basis for the design of development plans, investment decisions, and valuation of companies’ assets.

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