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ESTIMATING THE IN SITU MECHANICAL PROPERTIES OF SEDIMENTS CONTAINING GAS HYDRATES.Birchwood, Richard, Singh, Rishi, Mese, Ali 07 1900 (has links)
Estimating the in situ mechanical properties of sediments containing gas hydrates from seismic or
log data is essential for evaluating the risks posed by mechanical failure during drilling,
completions, and producing operations. In this paper, a method is presented for constructing
correlations between the mechanical properties of gas hydrate bearing sediments and geophysical
data. A theory based on micromechanics models was used to guide the selection of parameters
that govern the physical behavior of sediments. A set of nondimensionalized relations between
elastoplastic properties and those that could be inferred from log or seismic data was derived.
Using these relations, a correlation for the Young’s modulus was constructed for sands with
methane and THF hydrate using data from a wide variety of sources. It was observed that the
correlation did not fit data obtained from samples with high THF hydrate saturations, due
possibly to the existence of cohesive mechanisms that operate in such regimes.
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Reservoir and geomechanical coupled simulation of CO2 sequestration and enhanced coalbed methane recoveryGu, Fagang Unknown Date
No description available.
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Analyse du potentiel sismique d'un secteur lithosphérique au nord ouest des Alpes / Seismic potential analysis of a lithospheric sector north-west of the AlpsMaury, Julie 20 September 2013 (has links)
Le nord-ouest des Alpes est un domaine intraplaque présentant de très faibles déformations. C'est pourquoi il paraît délicat de déduire la probabilité d'occurrence d'un séisme de taille lithosphérique (magnitude supérieure à 7) à partir des observations de microsismicité. De telles observations sont en effet des processus superficiels et présentent peu ou pas de lien avec des processus profonds de plus grande ampleur. L'objectif est de déterminer le potentiel sismique d'un secteur au nord-ouest des Alpes en étudiant le champ de contrainte résultant d'un chargement gravitaire. Seuls les objets de taille lithosphérique, i.e. de l'ordre de la centaine de kilomètres sont pris en compte. Un modèle de contraintes à l'échelle 360 km par 400 km par 230 km d'épaisseur, centré sur la subduction fossile des Alpes de l'ouest et s'étendant jusqu'au nord de Strasbourg, est établi. L'étude des structures du nord-ouest alpin montre l'importance de l'orogène alpin qui se retrouve, enparticulier, dans les variations de profondeur des interfaces de la lithosphère. Une étude du champ de contrainte dans le socle a permis d'identifier une rotation des contraintes principales horizontales avec l'axe des Alpes. Bien que la valeur absolue des contraintes principales n'ait pas pu être déterminée, un rapport de valeur relative est calculé. Le résultat de la modélisation montre l'importance de la rhéologie dans le cas d'un chargement gravitaire. Si une rhéologie élastique est prise en compte, les directions de contrainte calculées sont totalement différentes des observations. Par contre, l'utilisation d'une rhéologie élasto-plastique combinée à l'utilisation d'une géométrie réaliste des interfaces lithosphériques permet d'obtenir des directions de contraintes cohérentes avec les données. / The north-west of the Alps is an intraplate domain with very slow deformations. So, it seems difficult to determine the probability of occurrence of a lithospheric earthquake (magnitude greater than 7) from microseismic observations. Such observations are superficial processes with little relation to deeper and bigger ones. The aim is to determine the seismic potential of a lithospheric sector north-west of the Alps, studying the stress field generated by a gravity driven model. This model is 360 km by 400 km by 230 km deep, centered on the west alpine fossil subduction and going up to the north of Strasbourg. The study of the north-west alpine structures shows the importance of the alpine orogen which generates variations in depth of the lithospheric interfaces. A study of the stress field in the basement shows a variation of principal stress directions along the strike of the Alpine chain. Even if the absolute magnitude of stresses could not be determined a relative magnitude ratio is calculated. Results underline the importance of rheology for a gravity driven model. If an elastic rheology is modeled, calculated stress directions do not match observations. However, using an elasto-plastic rheology with a realistic geometry of the lithospheric interfaces, we can obtain stress directions coherent with the data.
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Estudo da capacidade de carga de uma cÃlula experimental de resÃduos sÃlidos urbanos com base em ensaios de laboratÃrio e campo / Study of the capacity of an experimental cell of MSW based on laboratory tests and fieldAndressa de AraÃjo Carneiro 27 August 2013 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / In this research we study the geomechanical behavior of municipal solid waste from the
Metropolitan West Caucaia landfill (ASMOC) where tests were performed on the soil surface
and on residue of an experimental cell of municipal solid waste (MSW). Laboratory tests for
the soil samples characterization consisted of granulometric analyzes, density, consistency
indices, compaction Energy Standard Proctor and Index Support California (ISC) and for the
characterization of solid waste in situ tests were performed like composition of gravimetric,
moisture and specific weight. In field, tests were developed to determine the natural moisture
content, through Speedy, natural specific weight through sand flask, standard penetration test
(SPT) and plate load test.To evaluate the capacity of the MSW landfill, it was also held a
standard penetration test (SPT) and plate load tests on a portion of the former landfill waste
inside the ASMOC. It was settled yet superficial landmarks for the settlements monitoring in
the experimental cell. After analyzing the results, we evaluated the future use of the study area
for instance the foundation of small buildings, subgrade small access roads or green area of
playgrounds. Based on the results, it can be stated that it is possible to use the MSW disposal
area as support from foundations of small buildings, subgrade small access roads and green
area of playgrounds, since biodegradation processes have been terminated, drainage systems
of gas and leachate are rightly designed and that the soil surface is properly compacted. / Na presente pesquisa estuda-se o comportamento geomecÃnico dos resÃduos sÃlidos urbanos
provenientes do Aterro SanitÃrio Metropolitano Oeste de Caucaia (ASMOC), onde foram
realizados ensaios no solo de cobertura e no resÃduo, de uma cÃlula experimental de resÃduos
sÃlidos urbanos (RSU). Os ensaios de laboratÃrio para caracterizaÃÃo das amostras de solo
constou de anÃlises granulometrica, massa especÃfica, Ãndices de consistÃncia, compactaÃÃo na
Energia de Proctor Normal e Ãndice de Suporte CalifÃrnia (ISC) e para a caracterizaÃÃo dos
resÃduos sÃlidos in situ foram realizados ensaios de composiÃÃo de gravimÃtrica, umidade e
peso especÃfico. Em campo, foram desenvolvidos ensaios para determinaÃÃo do teor de
umidade natural, por meio do Speedy, do peso especÃfico natural, atravÃs do frasco de areia,
sondagens à percussÃo (SPT) e provas de carga direta. Para a avaliaÃÃo da capacidade de
carga do aterro de RSU realizou-se ainda uma sondagem à percussÃo (SPT) e provas de carga
direta em uma porÃÃo do aterro de resÃduo antigo no interior do ASMOC. Instalaram-se ainda
marcos superficiais para o monitoramento dos recalques na cÃlula experimental. ApÃs a
anÃlise dos resultados avaliou-se o uso futuro da Ãrea em estudo como: fundaÃÃo de pequenas
edificaÃÃes, subleito de pequenas vias de acesso e como Ãrea verde de parques recreativos.
Com base nos resultados pode-se afirmar que à possÃvel o uso da Ãrea de disposiÃÃo de RSU
como suporte de fundaÃÃes de pequenas edificaÃÃes, subleito de pequenas vias de acesso e
Ãrea verde de parques recreativos, desde que os processos de biodegradaÃÃo tenham sido
cessados, os sistemas de drenagem de gases e de chorume estejam devidamente
dimensionados e que o solo de cobertura esteja adequadamente compactado.
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Impact de la température sur les propriétés mécaniques et acoustiques des roches concernées par la production en SAGD, lors de l'injection de vapeur dans les réservoirs d'huile lourde / Effects of temperature on the mechanical and acoustical properties of rocks during the SAGD processDoan, Dinh Hong 10 October 2011 (has links)
L'injection de vapeur lors de la production des bruts lourds par SAGD soumet les roches réservoirs (sables bitumineux non consolidés ou faiblement consolidés) à une élévation de température (jusqu'à 280°C). L'apport de fluide chaud augmente la pression de pore, dilate le squelette rocheux et le fluide interstitiel, ce qui modifie le champ de contrainte in situ. Le travail de thèse, à forte connotation expérimentale, vise à contribuer à la caractérisation mécanique et acoustique des réservoirs bitumineux sous différentes conditions de température, de contrainte et de saturation. Les travaux ont été effectués sur des échantillons de sables bitumineux Canadiens, mais également sur un matériau modèle, un sable reconstitué artificiellement cimenté. Plusieurs techniques expérimentales ont été mises en œuvre pour caractériser les matériaux utilisés : tomographie RX, microtomographie RX, cryomicroscopie, RMN, etc. Des essais ont ensuite été effectués dans une cellule oedométrique, une cellule pétroacoustique et également dans une cellule triaxiale dite haute température qui a été développée dans le cadre de cette thèse.Les divers essais de chargement mécanique et thermique dans cette thèse ont permis d'enrichir les connaissances sur le comportement thermo-hydro-mécanique des sables bitumineux ainsi que celui des sables reconstitués. Les paramètres investigués ont été la dilatation thermique, la compressibilité sous chargement oedométrique et triaxial isotrope et la résistance au cisaillement. Les différentes mesures des propriétés acoustiques (vitesses Vp et Vs, atténuations et modules dynamiques) effectués sur les sables naturels et reconstitués ont montré l'importance des propriétés des fluides saturants, principalement de leur viscosité. Le bitume est un fluide viscoélastique avec une viscosité qui varie avec l'élévation de la température. Aux températures in situ, il se comporte comme un solide avec un module de cisaillement. L'approche théorique de Ciz et Shapiro (2007), permet de prendre en compte ce module de cisaillement du fluide visqueux et généralise l'équation de Biot Gassmann. Son utilisation a été validée sur nos essais. La modélisation prend en compte les aspect dispersifs et permet d'extrapoler aux fréquences sismiques des résultats acquis en laboratoire avec des fréquences ultrasonores. Les vitesses Vp et Vs diminuent avec le passage de la chambre de vapeur. Les variations sont faibles mais peuvent être identifiées par la sismique 4D / The steam assisted gravity drainage (SAGD) has been successfully used to enhance the recovery of heavy oil in Western Canada and Eastern Venezuela basins. Temperature, pressure and pore fluid variations during SAGD operations induce complex changes in the. properties of the heavy oil sand reservoir. This dissertation focuses on the geomechanical and acoustic behaviours of oil sand and how they change under various temperature, pressure and pore fluid conditions. Both natural oil sands samples and reconstituted samples were tested in this research program. Several experimental techniques have been used to characterize the materials including X-Ray tomography, X-ray microtomography, cryomicroscopy, NMR. Natural oil sands samples, characterized by high permeability, high porosity and an interlocked structure have been extracted from the estuarine McMurray Formation in Athabasca (Alberta, Canada). Reconstituted samples, made up of slightly cemented Fontainebleau sand, have been considered as possible analogues of the natural oil sands. Tests have been carried out in high pressure oedometer cells, in an isotropic pressure cell and in a new high temperature triaxial cell. The various geomechanical and thermal tests have been carried out to better understand the thermo-hydro-mechanical behaviour of natural oil sands and of reconstituted samples. The parameters investigated were the thermal dilatation, the bulk compressibility (under oedometric and isotropic loading) and the shear strength. The acoustic measurements (P and S-wave velocities, attenuations and dynamic modules, etc.) performed on natural oil sands and reconstituted samples showed the importance of the saturating fluids properties, mainly through viscosity. Bitumen has a viscoelastic behaviour with a non-negligible shear modulus that depends strongly on temperature and frequency and that allows shear wave propagation. The theoretical approach of Ciz and Shapiro (2007), that accounts for the effects of the shear modulus of the viscous fluid and generalizes the Biot – Gassmann equation, has been validated by our tests. The model takes into account the dispersive aspects and allows the results obtained in the laboratory with ultrasonic frequencies to be extrapolated to seismic frequencies. Velocities Vp and Vs decrease with the steam invasion. Changes are small but can be detected by 4D seismic
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Hydro-thermo-chemo-mechanical Modeling of Carbon Dioxide Injection in Fluvial Heterogeneous AquifersErshadnia, Reza 04 October 2021 (has links)
No description available.
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[en] 3D ROCK MASS GEOMECHANICAL MODELING TO EXCAVATED SLOPE BI-DIMENSIONAL STABILITY ANALYSIS AT AHE-SIMPLÍCIO POWER HOUSE / [pt] MODELAGEM GEOMECÂNICA TRIDIMENSIONAL DE MACIÇOS ROCHOSOS PARA ANÁLISE BIDIMENSIONAL DA ESTABILIDADE DOS TALUDES DE ESCAVAÇÃO DA CASA DE FORÇA DO AHE-SIMPLÍCIO02 December 2008 (has links)
[pt] Na engenharia geotécnica, o conhecimento das propriedades
geomecânicas de subsuperfície é fundamental aos cálculos
de
estabilidade. Na
prática cotidiana, a estimativa dessa distribuição é
realizada pelo
geólogo/geotécnico responsável, que traça seções
geológico-
geotécnicas em
função de sua experiência e da observação dos dados das
investigações de
campo e laboratório. Tais estimativas bidimensionais,
porém, não contemplam a
distribuição espacial. Assim, o objetivo deste trabalho é
enriquecer a
compreensão global do maciço com a previsão da
distribuição
tridimensional
dessas propriedades. Utilizou-se o modelador geológico
PETREL(TM) para a
estimativa geoestatística da variação espacial dos
valores
de RMR e grau de
fraturamento ao longo do maciço rochoso destinado à
implantação da casa de
força do Aproveitamento Hidrelétrico de Simplício. Essa
distribuição foi estimada
em função da disposição dos dados ao longo dos furos de
sondagem localizados
espacialmente no modelo. Também foi lançada a geometria
da
futura superfície
de escavação, para que se pudesse avaliar qual a seção
crítica de qualidade do
maciço em relação aos taludes de corte. Essa seção foi
então extraída do
modelo com a distribuição ponto a ponto do valor de RMR,
de
onde foram
obtidos os parâmetros de resistência c e Ø para a análise
de estabilidade.
Analisou-se então a estabilidade desse talude em um
programa que permite
essa variação espacial de parâmetros de resistência e, em
paralelo também
foram realizadas as análises convencionais de
estabilidade
de taludes rochosos,
de forma a apresentar a importância da modelagem
tridimensional para tal
estudo. / [en] In geotechnical engineering, the knowledge of geomechanical
subsurface
properties is fundamental to stability analyses. The usual
practice is that a
geologist/geotechnical engineer does this distribution
estimate. The professional
makes some geologic-geotechnical sections based on his/her
experience and by
the observation of field/laboratory investigations data.
But these 2D sections
cannot take spatial distribution. To solve this problem and
provide a better global
comprehension of rock mass, this work presents a study of
3D property
distribution. The geological modeler PETREL(TM) has been
used to do a
geostatistical estimate of RMR and fracture density spatial
variety at the rock
mass where the AHE Simplício`s power house will be
installed. This distribution
has been estimated based on data linked to the boreholes,
spatially arranged at
the model. The geometry of the future excavated surface was
introduced in the
model. The purpose was to carry out a study to find the
critical quality section of
the model related to the excavated slopes. This section was
extracted with its
RMR value distribution. Before the stability analysis, the
resistance parameters c
and Ø were calculated to every point on this section from
the RMR correlations.
The slope stability of the critical section was calculated
in a program where the
resistance parameters can vary point by point. The
conventional rock slope
stability analysis has been done too. At the end of the
study, the first analysis
was compared against the last one, proving the importance
of the subsurface
tridimensional modeling.
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Toward Better Understandings of Unconventional Reservoirs - Rock Mechanical Properties and Hydraulic Fracture PerspectivesGong, Yiwen January 2020 (has links)
No description available.
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EXAMINATION OF GEOLOGICAL INFLUENCE ON MACHINE EXCAVATION OF HIGHLY STRESSED TUNNELS IN MASSIVE HARD ROCKVilleneuve, MARLENE 27 September 2008 (has links)
A combined geological and rock mechanics approach to tunnel face behaviour prediction, based on improved understanding of brittle fracture processes during TBM excavation, was developed to complement empirical design and performance prediction for TBM tunnelling in hard rock geological conditions. A major challenge of this research was combining geological and engineering terminology, methods, and objectives to construct a unified Geomechanical Characterisation Scheme. The goal of this system is to describe the spalling sensitivity of hard, massive, highly stressed crystalline rock, often deformed by tectonic processes. Geological, lab strength testing and TBM machine data were used to quantify the impact of interrelated geological factors, such as mineralogy, grain size, fabric and the heterogeneity of all these factors at micro and macro scale, on spalling sensitivity and to combine these factors within a TBM advance framework. This was achieved by incorporating aspects of geology, tectonics, mineralogy, material strength theory, fracture process theory and induced stresses.
Three main approaches were used to verify and calibrate the Geomechanical Characterisation Scheme: geological and TBM data collection from tunnels in massive, highly-stressed rock, interpretation of published mineral-specific investigations of rock yielding processes, and numerical modelling the rock yielding processes in simulated strength tests and the TBM cutting process. The TBM performance investigation was used to identify the mechanism behind the chipping processes and quantify adverse conditions for chipping, including tough rock conditions and stress induced face instability. The literature review was used to identify the critical geological parameters for rock yielding processes and obtain strength and stiffness values for mineral-specific constitutive models. A texture-generating algorithm was developed to create realistic rock analogues and to provide user control over geological characteristics such as mineralogy, grain size and fabric.
This methodology was applied to investigate the TBM chipping process to calibrate the Geomechanical Characterisation Scheme. A Chipping Resistance Factor was developed to combine the quantified geological characteristic factors and laboratory strength values to predict conditions with high risk of poor chipping performance arising from tough rock. A Stress-Related Chip Potential Factor was developed to estimate conditions with high risk of advance rate reduction arising from stress-induced face instability. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-09-25 23:58:58.071
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Etude des mécanismes élémentaires de l'érosion d'un sol cohésif / Study of the elementary mechanisms of erosion mechanisms of cohesive granular materialsBrunier-Coulin, Florian 29 November 2016 (has links)
Les mécanismes élémentaires mis en jeu lors de l’érosion de surface d’un sol cohésif par un écoulement fluide demandent à être mieux connus dans le but d’améliorer la modélisation locale de l’érosion. En se basant sur une approche expérimentale, l’objectif de cette thèse vise à réaliser une étude paramétrique de l'érosion à l'aide de matériaux modèles, pour ensuite les soumettre à des sollicitations hydrodynamiques et mécaniques contrôlées. L'étude de matériaux granulaire sans cohésion a d'abord permis d'analyser la construction du nombre de Shields pour définir le seuil d'érosion. Ensuite, des essais de traction à différentes échelles ont permis de généraliser le nombre de Shields à des grains cohésifs par la relation entre seuil d'érosion et résistance mécanique. La mise au point de matériaux et d'essais d'érosion iso-indice a également permis de visualiser les mécanismes par lesquels l'écoulement conduit à l’arrachement de particules constitutives du matériau modèle lors d'essais de JET et de HET. Pour finir, d'autres types de matériaux cohésifs modèles ont été plus rapidement étudiés et révèlent de grandes perspectives d'études. / Elementary mechanisms involved during the surface erosion of a cohesive soil by a fluid flow ask to be better understood for improving the local modeling of erosion. It is the objective of this thesis which aims, by an experimental approach, at working out model materials to submit them to hydrodynamic stresses and controlled mechanic stresses. The study of cohesion-less granular material allowed, in a first approach, to analyse the Shields number formulation to define the erosion threshold. In a second time, the grains have been made cohesive with liquid or solid matrix, and mechanical tests at different scales allowed to generalise the Shields number to both cohesive and non-cohesive particles. The development of erosion tests adjusted in optical index also made possible to visualised the mechanisms by which the fluid flow erode the constitutive particles of the material during Jet Erosion Tests and Hole Erosion Tests. Finally, different kinds of cohesive model materials were tested and show excellent perspectives.
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