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1
Freiman, Gabriel, Jean-Pierre Korb, Benjamin Nicot e Patrice Ligneul. "Microscopic wettability of carbonate rocks". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192328.
Testo completoAbstract (sommario):
Nuclear Magnetic Relaxation Dispersion (NMRD) is strongly sensitive to the microscopic wettability of oil and brine bearing carbonate rocks. Exploring a very large range of low frequency enables isolating the typical NMRD dispersion features, 1/T1Surf, associated to
the different processes of molecular surface dynamics. This allows a separation of the surface and bulk microdynamics of oil and water even for a biphasic saturation of petroleum rocks. Several surface dynamical parameters were determined and related to the concept of microscopic wettability of oil and water in porous media.
2
Dong, Chengli. "Acidizing of naturally-fractured carbonate formations". Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3031042.
Testo completo
3
Schmidt, Volkmar. "Magnetic and mineral fabrics in carbonate rocks /". Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17090.
Testo completo
4
Berhanu, Solomon Assefa. "Seismic and petrophysical properties of carbonate reservoir rocks". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262633.
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5
Bosak, Tanja Kirschvink Joseph L. "Laboratory models of microbial biosignatures in carbonate rocks /". Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-12102004-144939.
Testo completo
6
Huang, Wentao, Peter C. Lippert, Yang Zhang, Michael J. Jackson, Mark J. Dekkers, Juan Li, Xiumian Hu, Bo Zhang, Zhaojie Guo e Hinsbergen Douwe J. J. van. "Remagnetization of carbonate rocks in southern Tibet: Perspectives from rock magnetic and petrographic investigations". AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/624349.
Testo completoAbstract (sommario):
The latitudinal motion of the Tibetan Himalayathe northernmost continental unit of the Indian plateis a key component in testing paleogeographic reconstructions of the Indian plate before the India-Asia collision. Paleomagnetic studies of sedimentary rocks (mostly carbonate rocks) from the Tibetan Himalaya are complicated by potentially pervasive yet cryptic remagnetization. Although traditional paleomagnetic field tests reveal some of this remagnetization, secondary remanence acquired prior to folding or tilting easily escapes detection. Here we describe comprehensive rock magnetic and petrographic investigations of Jurassic to Paleocene carbonate and volcaniclastic rocks from Tibetan Himalayan strata (Tingri and Gamba areas). These units have been the focus of several key paleomagnetic studies for Greater Indian paleogeography. Our results reveal that while the dominant magnetic carrier in both carbonate and volcaniclastic rocks is magnetite, their magnetic and petrographic characteristics are distinctly different. Carbonate rocks have wasp-waisted hysteresis loops, suppressed Verwey transitions, extremely fine grain sizes (superparamagnetic), and strong frequency-dependent magnetic susceptibility. Volcaniclastic rocks exhibit pot-bellied hysteresis loops and distinct Verwey transitions. Electron microscopy reveals that magnetite grains in carbonate rocks are pseudomorphs of early diagenetic pyrite, whereas detrital magnetite is abundant and pyrite is rarely oxidized in the volcaniclastic rocks. We suggest that the volcaniclastic rocks retain a primary remanence, but oxidation of early diagenetic iron sulfide to fine-grained magnetite has likely caused widespread chemical remagnetization of the carbonate units. We recommend that thorough rock magnetic and petrographic investigations are prerequisites for paleomagnetic studies throughout southern Tibet and everywhere in general.
7
Huang, Tianping. "Wormhole modeling in carbonate acidizing /". Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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8
El-Maghraby, Rehab Motasiem Nasr Ali. "Measurements of CO₂ trapping in carbonate and sandstone rocks". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11066.
Testo completoAbstract (sommario):
CO2 storage in saline aquifers (sandstone/carbonate types) has been proposed as a promising solution to help reduce CO2 emissions to the atmosphere. CO2 will likely be stored as a dense, supercritical (sc.) phase. There are different mechanisms by which CO2 could be stored safely underground; structural and stratigraphic trapping, dissolution trapping, capillary trapping, and mineral trapping. I study capillary trapping. We assume that in the middle of a CO2 plume, many kilometres in extent, the CO2, brine and rock have been in mutual contact for several years. In these circumstances, the degree of capillary trapping is determined by a displacement of CO2 by brine under these equilibrated conditions. Reproducing such conditions in the laboratory poses a challenge. I have measured the first trapping curve, the relation between initial and residual CO2 saturation, for carbonates in the literature, as well as contributing to the first data on sandstones. For capillary trapping experiment, the porous plate method was used during primary drainage. Two sandstones (Berea and Doddington) and two types of carbonates (Ketton and Indiana) were studied. These experiments were conducted at temperatures of 33, 50, and 70 ˚C and 9 MPa pressure, which matches the conditions observed for several current and planned storage sites. Two displacement steps, primary drainage and water flooding were followed to reach residually trapped CO2 saturation. The isothermal de-pressurization method was used to measure the amount of scCO2 residually trapped. The drainage capillary pressure curve, the Leverett J-function and the trapping curve were measured. During capillary trapping experiments, the brine was equilibrated with CO2 to achieve immiscible displacement. We used a stirred reactor, to equilibrate CO2 with brine. The solubility of CO2 in brine was also measured using the isothermal depressurization method and compared with data in the literature.In Berea sandstone the trapping curves at 33, 50 and 70˚C were compared. We showed that temperature (density) variation has no effect on the saturation of scCO2 that is residually trapped. In Doddington sandstone our result was consistent with that from a micro-flow cell in which the trapped scCO2 was imaged using an X-ray source at the pore scale. We find that significant quantities of the CO2 can be trapped, with residual saturations up to 35%, but less than in analogue experiments where oil is displaced by brine. Hence, it is hypothesized that scCO2-brine systems in sandstones are weakly water-wet with less trapping than the more strongly wetting analogues. Capillary trapping in carbonates is very challenging. In carbonates, another step was required, where brine/CO2/carbonate will be equilibrated together before running the capillary trapping experiment. The apparatus used for sandstone rocks was modified so that the geochemical reaction between CO2/rock was accounted for. Samples are taken and analysed to ensure that the brine/CO2 mixture is saturated with carbonate minerals. In Indiana, the CO2 trapping curve for scCO2 at 50 ˚C and 9 MPa was compared with that of gaseous CO2 at 50 ˚C and 4.2 MPa. A scCO2 residual trapping endpoint of 23.7% was observed in Indiana for scCO2, with a smaller trapping end point in Ketton limestone. This indicates a slightly less trapping of scCO2 in carbonates than in sandstone. There is also less trapping for gaseous CO2 (endpoint of 18.8%). The system appears to be more water-wet under scCO2 conditions, which is different from the trend observed in Berea; the greater concentration of Ca2+ in brine at higher pressure was hypothesised to lead to more water-wet conditions. Our work indicates that capillary trapping could effectively store CO2 in carbonate aquifers.
9
Johnson, Aaron W. "Regional-scale geochemical analysis of carbonate cements : reconstructing multiple fluid interactions related to dolomitization and mineralization in lower carboniferous rocks of the Irish Midlands /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3101027.
Testo completo
10
Stafford, Kevin Wayne. "Structural controls on megaporosity in eogenetic carbonate rocks Tinian, CNMI /". Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-10302003-080242.
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11
Anselmetti, Flavio Stefano Anselmetti Flavio Stefano Anselmetti Flavio Stefano Anselmetti Flavio Stefano. "Physical properties and seismic response of carbonate sediments and rocks /". [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10845.
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12
Reece, Matthew A. "Origin and morphology of notches in carbonate cliffs and hillslopes implications for paleoclimate and paleohydrology /". Master's thesis, Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-03102004-105006.
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13
Overfield, Bethany L. "A CLASSIFICATION OF LOWER PALEOZOIC CARBONATE-BEARING ROCKS FOR GEOTECHNICAL APPLICATIONS". UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/127.
Testo completoAbstract (sommario):
An empirically-based classification of lower Paleozoic carbonate-bearing rocks was created for field-based geotechnical applications. Geotechnical parameters were subsequently correlated to that classification. Seven hundred seventy-seven samples were used as the basis for the classification. Thirteen categories based on visual and tactile properties and a hydrochloric acid test were created. Samples were from central, north-central, and south-central Kentucky and represented the majority of Ordovician exposures in the state, and some Mississippian exposures. Few Silurian and Devonian units were included in the sample set. Geotechnical parameters, including density as well as elastic constants (shear and compression wave velocities, Poisson’s ratio, Young’s modulus, and shear modulus), were calculated for 113 representative samples from the classification. Compression strength testing was completed on 29 samples and the slake durability index was calculated for 18 samples. Testing values were correlated to the classification system in an attempt to use the classification as a predictive and comparative tool for geotechnical applications. Despite samples being heterogeneous and isotropic, each of the 13 categories behaved differently and predictably, with the sharpest contrast in siliciclastic and carbonate rocks.
14
PARRA, DARIO PRADA. "NUMERICAL AND EXPERIMENTAL ANALYSIS OF LASER-BASED PERFORATION IN CARBONATE ROCKS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33675@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Atualmente, os lasers de alta potência estão sendo testados pela indústria de petróleo como ferramentas de perfuração. Isto ocorre visando dois objetivos fundamentais: (i) aumentar a eficiência na perfuração de poços (maior taxa de penetração) e (ii) melhorar o controle da geometria do corte de revestimento no processo de canhoneio de poço. Este trabalho tem como objetivo contribuir para a tecnologia de canhoneio a laser em rochas carbonáticas através do desenvolvimento de técnicas para aumentar o volume de rocha removida por unidade de tempo. Estudou-se o comportamento termomecânico das rochas carbonáticas quando um laser é utilizado como ferramenta de perfuração no processo de canhoneio. Este conhecimento, obtido através de experimentos e simulações, forneceu dados para a otimização dos parâmetros de perfuração. Foram investigadas as condições de perfuração estática (não há movimentação do feixe do laser) e dinâmica (o feixe do laser percorre uma trajetória espiral). Além disso, foram investigados os resultados da perfuração sob pressão atmosférica e também utilizando uma câmara de pressão projetada para emular a pressão confinante do reservatório. Foram realizados testes experimentais de perfuração a laser com corpos de prova feitos a partir da rocha Bege Bahia. O Bege Bahia é um afloramento utilizado para simular as rochas encontradas nos reservatórios do Pré-sal. A análise destes corpos de prova foi feita através de inspeção e da caracterização por microtomografia, permitindo observar e caracterizar as propriedades da rocha, além da zona termicamente afetada (ZTA), características geométricas do furo, e valores da energia específica da perfuração. Estes resultados foram comparados com resultados obtidos através de simulações. Na modelagem numérica, o processo de canhoneio foi simulado pelo método de elementos finitos através de um modelo termomecânico elástico transiente axissimétrico que verificou as condições de perfuração. O modelo numérico permitiu observar o comportamento das tensões e temperaturas nos testes que envolvem altas temperaturas e altas pressões. Estas grandezas são usualmente difíceis de serem medidas em ensaios experimentais e, portanto, não foram observadas nos ensaios experimentais discutidos nesta tese. Também foram obtidos através da modelagem numérica valores para propriedades da rocha e da zona termicamente afetada (ZTA), características geométricas do furo, e valores da energia específica da perfuração. Os resultados numéricos obtidos foram comparados com resultados dos ensaios experimentais. Os resultados obtidos mostraram que a condição de perfuração dinâmica consegue remover uma quantidade maior de material e produzir uma ZTA maior em Comparação com o teste estático, gerando uma melhor relação tempo x potência. Os testes estáticos e dinâmicos permitiram se chegar às condições de canhoneio mais eficientes para a perfuração da rocha. A análise de tensões do modelo mostrou uma correlação compatível com o perfil do dano encontrado nos ensaios experimentais.
Currently, the petroleum industry is testing high power lasers as drilling tools. The use of these lasers for this application has two main reasons: (i) to increase the efficiency of well drilling (higher penetration rate) and (ii) to improve the control of the geometry of the hole in the casing during the perforation process of the well. The present thesis has the purpose of contributing to the laser perforation technology in carbonate rocks by developing techniques to increase the volume of rock removed by unit of time. The thermo-mechanical behavior of the carbonate rocks was studied when a laser is used as the drilling tool in the perforation process. This knowledge, obtained through experiments and simulations, supplied data for the optimization of the drilling parameters. Both static (the laser beam does not move) and dynamic (the laser beam moves in a spiral trajectory) drilling conditions were investigated. Also investigated were drilling conditions under atmospheric pressure and under high pressure, where a pressure chamber designed to emulate pressure conditions of reservoirs was used. Experimental tests were performed by laser drilling samples made of Bege Bahia rock. This rock is used to simulate rocks found in pre-salt reservoirs. The analysis of these samples was performed through inspection and microtomography characterization, allowing the observation of properties of the rocks and of the heat affected zone (HAZ), geometric characteristics of the hole, and values of the drilling specific energy. These results were compared to the results obtained by simulations. In the numerical modeling, the perforation process was simulated with the finite element method through a transient axisymmetric thermo-mechanical elastic model that verified the drilling conditions. The numerical model allowed the observation of the behavior of the tensions and temperatures in tests involving high temperatures and pressures. These properties are usually difficult to measure in experimental tests and, therefore, were not measured during the experimental tests discussed in this thesis. Also obtained by numeric modeling were: properties of the rock and of the HAZ, geometric characteristics of the hole, and values of the drilling specific energy. The numeric results obtained were compared to the experimental results. The results obtained showed that the dynamic drilling condition is able to remove a larger amount of material and produce a larger HAZ, compared to the static condition, thus generating a better time x power relation. The static and dynamic tests allowed reaching more efficient conditions for rock drilling. The analysis of the tension of the model showed a compatible correlation with the damage profile found in the experimental tests.
15
Freiman, Gabriel, Jean-Pierre Korb, Benjamin Nicot e Patrice Ligneul. "Microscopic wettability of carbonate rocks: a proton field cycling NMR approach". Diffusion fundamentals 10 (2009) 25, S. 1-3, 2009. https://ul.qucosa.de/id/qucosa%3A14116.
Testo completoAbstract (sommario):
Nuclear Magnetic Relaxation Dispersion (NMRD) is strongly sensitive to the microscopic wettability of oil and brine bearing carbonate rocks. Exploring a very large range of low frequency enables isolating the typical NMRD dispersion features, 1/T1Surf, associated to
the different processes of molecular surface dynamics. This allows a separation of the surface and bulk microdynamics of oil and water even for a biphasic saturation of petroleum rocks. Several surface dynamical parameters were determined and related to the concept of microscopic wettability of oil and water in porous media.
16
Russell, Jonathan. "Investigation of the potential of Pb/Pb radiometric dating for the direct age determination of carbonates". Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:c28f08cd-9a27-4ed1-b7eb-eda43ecb469b.
Testo completoAbstract (sommario):
Recent studies have demonstrated the potentially robust nature of U-Pb and Pb/Pb systematics within certain sedimentary and metamorphic carbonates (e.g. Moorbath et al., 1987; Jahn, 1988; Jahn et al., 1990; DeWolf and Halliday, 1991). During the course of this work, the Pb/Pb dating technique has been applied successfully to the direct dating of Proterozoic stromatolitic carbonates from Western Australia and India, Silurian stromatoporoidal carbonates from Sweden and Archaean marbles from India, permitting the direct age determination of depositional/early diagenetic, late diagenetic and metamorphic events. Results indicate that large variations in μ value (238U/204Pb) and virtually homogeneous initial Pb isotopic compositions are a recurrent feature of sedimentary and metamorphic carbonates. Authigenic marine carbonates may incorporate U and Pb through a variety of geochemical mechanisms; - organic complexing;
- crystal lattice substitution;
- adsorption onto particulate oxyhydroxides and
- early diagenetic reduction.
17
Haines, Thomas J. "The evolution of petrophysical properties across carbonate hosted normal fault zones". Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=225315.
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18
Barnhoorn, Auke. "Rheological and microstructural evolution of carbonate rocks during large strain torsion experiments /". [Zurich] : [s.n.], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15309.
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19
Osleger, David Allen. "Cyclostratigraphy of Late Cambrian cyclic carbonates : an interbasinal field and modelling study, U.S.A. /". Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03262008-175224/.
Testo completo
20
Shim, Moojoon. "Techniques for the analysis of carbonate-associated sulfate (CAS) concentrations in modern and ancient limestones and dolostones /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426105.
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21
Van, Stempvoort Dale. "Chazy group carbonate sedimentology and diagenesis : southern Quebec". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63375.
Testo completo
22
Power, Matthew R. "Models for the genesis of industrial minerals in mafic and ultramafic rocks". Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245925.
Testo completo
23
Huang, Wentao, Peter C. Lippert, Michael J. Jackson, Mark J. Dekkers, Yang Zhang, Juan Li, Zhaojie Guo, Paul Kapp e Hinsbergen Douwe J. J. van. "Remagnetization of the Paleogene Tibetan Himalayan carbonate rocks in the Gamba area: Implications for reconstructing the lower plate in the India-Asia collision". AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/623053.
Testo completoAbstract (sommario):
The characteristic remanent magnetization (ChRM) isolated from Paleogene carbonate rocks of the Zongpu Formation in Gamba (28.3 degrees N, 88.5 degrees(E) of southern Tibet has previously been interpreted to be primary. These data are pertinent for estimating the width of Greater India and dating the initiation of India-Asia collision. We have reanalyzed the published ChRM directions and completed thorough rock magnetic tests and petrographic observations on specimens collected throughout the previously investigated sections. Negative nonparametric fold tests demonstrate that the ChRM has a synfolding or postfolding origin. Rock magnetic analyses reveal that the dominant magnetic carrier is magnetite. "Wasp-waisted" hysteresis loops, suppressed Verwey transitions, high frequency-dependent in-phase magnetic susceptibility, and evidence that > 70% of the ferrimagnetic material is superparamagnetic at room temperature are consistent with the rock-magnetic fingerprint of remagnetized carbonate rocks. Scanning electron microscopy observations and energy-dispersive X-ray spectrometry analysis confirm that magnetite grains are authigenic. In summary, the carbonate rocks of the Zongpu Formation in Gamba have been chemically remagnetized. Thus, the early Paleogene latitude of the Tibetan Himalaya and size of Greater India have yet to be determined and the initiation of collision cannot yet be precisely dated by paleomagnetism. If collision began at 59 +/- 1 Ma at similar to 19 degrees N, as suggested by sedimentary records and paleomagnetic data from the Lhasa terrane, then a huge Greater India, as large as similar to 3500-3800 km, is required in the early Paleogene. This size, in sharp contrast to the few hundred kilometers estimated for the Early Cretaceous, implies an ever greater need for extension within Greater India during the Cretaceous.
24
Fahimpour, Jalal. "Wettability alteration of carbonate rocks to alleviate condensate blockage around gas-condensate wells". Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/2926.
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25
Huff, Timothy A. "Fluid inclusion evidence for metamorphic fluid evolution in the Black Hills, South Dakota /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1421144.
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26
Tsoflias, Georgios Padelis. "Hydrogeologic characterization of fractured carbonate aquifers employing ground-penetrating radar /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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27
Whiteman, Mark Ian. "The anatomy of Mesozoic carbonate platform-margins, southern Apennines, Italy". Thesis, University of Oxford, 1989. http://ora.ox.ac.uk/objects/uuid:f4df240b-cce7-4ac6-8c40-504e2187d018.
Testo completoAbstract (sommario):
The stratigraphy and sedimentology of Mesozoic carbonate platform-margins cropping out in southern Italy are investigated. New strati graphic data are presented from northern and eastern slopes of the Apennine carbonate platform, based on locallycorrelated field sections. Thin-section petrography is used to demonstrate the spatial and temporal distribution of derived lithoclasts. Results indicate that southern Apennine platforms underwent repeated erosion during Cretaceous time and possible reasons for this are discussed. Petrographic studies also provided outline sediment parageneses for slopes and platforms, with special reference to the detailed geochemistry of secondary dolomite formation on the eastern margin of the Apulian platform, whose growth is indicated by proton microprobe microanalysis to have been influenced by redox changes. The sedimentary facies and sediment geometries of Upper Cretaceous to Lower Tertiary slope sediments mapped in the Frosolone area are discussed in a case-study. Cross-sections showing geometries of key beds are presented, and depositional controls are discussed. Outcrop data suggest an Early to Middle Jurassic age of basin formation of this sector of the Lagonegro-Molise basin. A further case study from the Mesozoic slope in the Gran Sasso shows sediment geometries at reflection seismic scale, and relates them to possible depositional control by relative sea-level fluctuations. Finally, data from southern Apennine platforms and basins are combined in a tentative sequence stratigraphic framework for the Middle Cretaceous. The results of onedimensional subsidence modelling are presented in order to separate and describe the signals of local tectonics and relative sea-level fluctuations affecting the southern passive-margin of Mesozoic Tethys.
28
León, Carrera María Fernanda. "Diagenesis characterization and modeling of carbonate rocks : application to Mississippian lime (Oklahoma, United States of America)". Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS542.
Testo completoAbstract (sommario):
La diagenèse fait référence à tous les processus physico-chimiques qui transforment les sédiments. Dans le calcaire du Mississippien, les roches ont été soumises à une histoire géologique et diagénétique complexe qui rend leur exploitation d'hydrocarbures difficile. Maintenant, l'industrie pétrolière et gazière fait face à d'importants défis pour maintenir le plateau de production et identifier les zones productives restantes. Par conséquent, la caractérisation et l'interprétation des processus diagénétiques sont cruciales pour comprendre l'évolution et la distribution des propriétés de porosité et de perméabilité. De plus, la diagenèse est rarement prise en compte dans la modélisation standard des réservoirs carbonatés. Ceci peut s'expliquer par les difficultés dans la modélisation des surimpressions diagénétiques et la complexité ajoutée dans l'ajustement historique des données de production. Ce travail porte sur la caractérisation diagénétique et la modélisation des roches carbonatées, appliquées à un noyau extrait du calcaire du Mississippien. Et une méthodologie innovante est proposée pour intégrer les phases diagénétiques à l'intérieur du modèle géologique dans le cadre du workflow de modélisation et de l’ajustement historique de la productionDiagenesis refers to all the physicochemical processes that transform sediments. In the Mississippian Limestone, the rocks have been submitted to a complex geological and diagenetic history that makes its hydrocarbon exploitation difficult. Now, the oil and gas industry faces important challenges to keep production plateau and identify remaining productive areas. Therefore, the characterization and interpretation of diagenetic processes are crucial in order to understand the evolution and distribution of porosity and permeability properties. Moreover, diagenesis is rarely taken into account in the standard modeling of carbonate reservoirs. This can be explained by the difficulties in the modeling of diagenetic overprints and the complexity added in the historical adjustment of production data. This work addresses the diagenesis characterization and modeling of carbonate rocks, applied to a core extracted from the Mississippian Limestone. And an innovative methodology is proposed to incorporate the diagenetic phases inside the geological model as part of the modeling and the history-matching workflow
29
Paipe, Félix António Guimarães. "Masters Thesis Effect of Brine Concentration on Flow Properties in Two Types of Carbonate Rocks Ekofisk Chalk and Iranian Limestone : Study of Chemical Effect of Brine Composition on Flow Properties on Carbonate Rocks". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19269.
Testo completoAbstract (sommario):
SummaryThe displacement of oil from reservoir rock pore spaces is a function of many interacting variables, amongst which the reservoir wetting state has been shown to be one of the important affected by the rock lithology, oil chemistry and brine salinity. A finding from previous research says that the injection brine into oil saturated core plug increased oil recovery. Based on this the objective of this master thesis is to investigate the effect of brine concentration on flow properties in two types of carbonate rocks for enhanced oil recovery (EOR) through imbibition and water flooding processes.The methodology used to evaluate the effect of brine concentration (BC) and chemical composition (CC) for oil recovery consisted on two stages. The first stage covers the literature review regarding the effect of brine concentration and chemical composition, including carbonates (chalk and limestone) characteristics. The second stage is related to the laboratory experiment which was performed using n-Decane oil, six (6) brines with different concentrations and chemical composition and the six (6) core plugs where four (4) “chalks” from Ekofisk (Norway) and the other two (2) “limestones” from Iranian field. The experiment was carried out in the laboratory of Institute of Petroleum and Technology (IPT), the materials, chemicals products, apparatus and equipments, methodology and procedures were provided by the IPT laboratory.To carry out the laboratory experiments, initially the two cores from Iranian were cleaned before being used. Different properties of brines, cores and oil were measured using different methods and procedures; and results were computed. Next, each core was saturated with one type of brine and after that flooded by n-Decane oil for establishment of initial water saturation and determination of volume of oil produced by drainage process at room temperature conditions at one bar. After that, all cores were aging about 15 days at room temperature condition. Finally, each core was flooded using brine by imbibition process at room temperature conditions.Results achieved were computed and discussed based on the literature review and compared with “A salinity (AS) Ekofisk core reference case” and similar studies. From this study was observed that the matrix block has a high porosity. The average porosity was about 40.24% of the volumes of large pores. The average absolute permeability was about 3.73 mD which is low because the microporous dominate the pore network. The average brine density (ρ) was about1.026 g/cm3 and pH was about 7.25. The initial water saturation varies between 14.58 to 28.50% and residual oil saturation among 22.49 to 62%. The sleeve pressure in the cylinder was kept from 15 to 28 bar. During waterfloodig was observed that the breakthrough pressure drop and time to increases when the oil recovery increase.The highest original oil in place (OOIP) was achieved in the low salinity (LS) core which was about 68.46% and the lowest was recorded in the C salinity (CS) core which was around 26.71%. The reason of the high and the low recovery is related with the effect of brine concentration and chemical composition of Sodium, Calcium, Magnesium and Sulphate, added in the solution. The main driving mechanism for low salinity waterflooding is believed to be multi component ionic exchange made possible by the expansion of electrical double layer. The permeability and porosity of the cores can be pointed as other factor. In general, it was showen that there is an increase in oil recovery as the salinity decreases.
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Nicolaides, Stelios. "Dolomitization of the Early to Middle Cambrian carbonate rocks of Georgina Basin, Northern Territory, Australia /". Title page, contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09SM/09smn637.pdf.
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Jurgawczynski, Mathieu. "Predicting absolute and relative permeabilities of carbonate rocks using image analysis and effective medium theory". Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441333.
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Becker, Ivy [Verfasser]. "Structural and diagenetic controls on reservoir quality in tight siliciclastic and carbonate rocks / Ivy Becker". Karlsruhe : KIT Scientific Publishing, 2018. http://www.ksp.kit.edu.
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Khather, Mohamed. "Experimental Evaluation of Variation in Petrophysical Properties during CO2 Injection in Carbonate Rocks: Effective Mechanisms". Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/73568.
Testo completoAbstract (sommario):
Core flooding experiments were conducted in this research to evaluate changes in petrophysical properties of a number of carbonate samples (limestone, dolostone and chalk). The experiments involved carbonated brine flooding, CO2 enhanced oil recovery (CO2-EOR), and Water-Alternating Gas (WAG) processes performed under in-situ reservoir conditions.
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Owen, Athena Marie. "Tafoni caves in quaternary carbonate eolianites examples from the Bahamas /". Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-05142007-143443.
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Maher, Marie A. Bonem Rena Mae. "Comprehensive model for modern lagoonal patch reef systems in Discovery Bay, Jamaica". Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5029.
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Moore, Andrew Lathrop. "Combined use of lcast-size measurements and wave-tank experiments to estimate Pleistocene tsunami size at Molokai, Hawaii /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/6720.
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Bastos, de Paula Osni. "Elastic properties of carbonates : measurements and modelling". Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/1417.
Testo completoAbstract (sommario):
This thesis is a multi-scale study of carbonate rocks, from the nanoscale and digital rock investigations to the imaging studies of carbonate reservoir analogues. The essential links between these extremes are the carbonate physical properties and rock-physics models, which are investigated here through the modelling of ultrasonic wave propagation in carbonate samples, focusing on elastic stress sensitivities, saturating fluids and porosity models. Validation of Gassmann fluid substitution in carbonates is also investigated using correlations between core and well log measurements.On the nanoscale, we use the nanoindentation technique in an oolitic limestone to directly measure the calcite Young modulus and derive bulk and shear moduli. We have found a large variation in the calcite bulk modulus, from 56 to 144 GPa. The high values obtained in some oolite rings were interpreted as genetically associated with biologically generated calcite (biocalcite). There are many measurements that achieve these values in brachiopod shells, but none in oolitic limestone. We associate the smaller values with microporosity, which is undetectable by our microCT or even SEM images. On the microscale we use the X-ray microCT images. From these images we can compute oolite elastic parameters using finite difference methods (FDM). In this oolite sample, calcite was segmented in two distinct phases. Nanoindentation provides the elastic parameters for each phase. The results of the modelling are compared with ultrasonic measurements on dry samples.To compute the properties of rocks on fluid-saturated samples, one needs to use fluid substitution methods, such as Gassmann’s equations. However, the applicability of Gassmann’s equations and the fluid substitution technique to carbonate rocks is still a subject of debate. Here we compare the results of fluid substitution applied to dry core measurements against sonic log data. The 36 meters of continuously sampled carbonates data, comes from a cretaceous reservoir buried at a depth of 5000 metres in the Santos Basin, offshore Brazil. Compressional and shear velocities, density and porosity were measured in 50 samples covering the entire interval. We obtain good agreement between the elastic properties obtained from core and log measurements. This shows that Gassmann’s fluid substitution is applicable to these carbonates, at least at sonic log frequencies.Carbonate microstructure is investigated using the stress dependency of shear and compressional wave velocities according to the dual porosity model of Shapiro (2003). The model assumes that the pore space contains two types of pores: stiff and compliant pores. Understanding the parameters of this model for different rocks is important for constraining stress effects in these rocks. The results for a carbonate dataset from the Santos Basin show a good correlation between compliant porosity and dry bulk modulus, total porosity and density for 29 samples of carbonates from the Santos Basin. The correlations seem to be different for different facies distribution, with different trends for mudstone facies and grainstone and rudstone facies. We also performed the same analysis using 66 samples of sandstones of diverse origins (Han et al., 1986): a good correlation appears between compliant porosity and the dry bulk modulus for all samples.If we correlate only the 7 samples from Fontainebleau sandstone, a good correlation also appears between total and compliant porosity. This analysis shows that the correlation is facies dependent also for sandstones.While Gassmann’s equations may be valid for low frequencies, they are not applicable at higher frequencies, where squirt dispersion is significant. We propose a workflow to model wave dispersion and attenuation due to the squirt flow using the geometrical parameters of the pore space derived from the stress dependency of elastic moduli on dry samples. Our analysis shows the dispersion is controlled by the squirt flow between equant pores and intermediate pores (with aspect ratios between 10-3 - 2·10-1). Such intermediate porosity is expected to close at confining pressures of between 200-2000 MPa. We also infer the magnitude of the intermediate porosity and its characteristic aspect ratio. Substituting these parameters into the squirt model, we have computed elastic moduli and velocities of the water-saturated rock and compared these predictions against laboratory measurements of these velocities.The agreement is good for a number of clean sandstones, but much worse for a broad range of shaley sandstones. Our predictions show that dispersion and attenuation caused by the squirt flow between compliant and stiff pores may occur in the seismic frequency band. Confirmation of this prediction requires laboratory measurements of elastic properties at these frequencies.The carbonate system of Telegraph Station, Shark Bay (WA), is a unique environment where coquinas, stromatolites and microbial mats are linked: an excellent analogue to carbonate pre-salt offshore Brazil. We acquired 7.5 km of GPR data and high resolution seismic data in the coquina ridges. They are composed by calcite shells deposited by cyclones, which show excellent high resolution GPR images, being a low loss dielectric medium. Three classes of coquinas were mapped: tabular layers, convex-up crest and washover fan. From the correlation of 14C dating of 50 samples and the mapped events we can estimate an average rate of one event every 13 years. From our interpretation the Holocene regression is continuous but not homogeneous. Carbonate dissolution features, faults, trends and discontinuities were mapped. Analysis of these features helps us understand reservoir porosity and permeability distribution in carbonate deposits, and can be used to constrain reservoir properties in pre-salt carbonates in Brazilian basins.
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Petracchini, Lorenzo <1979>. "Characterization of fold-related fractures in the carbonate rocks of the Cingoli anticline, northern Apennines, Italy". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5770/.
Testo completoAbstract (sommario):
Thrust fault-related folds in carbonate rocks are characterized by deformation accommodated by different structures, such as joints, faults, pressure solution seams, and deformation bands. Defining the development of fracture systems related to the folding process is significant both for theoretical and practical purposes. Fracture systems are useful constrains in order to understand the kinematical evolution of the fold. Furthermore, understanding the relationships between folding and fracturing provides a noteworthy contribution for reconstructing the geodynamic and the structural evolution of the studied area. Moreover, as fold-related fractures influence fluid flow through rocks, fracture systems are relevant for energy production (geothermal studies, methane and CO2 , storage and hydrocarbon exploration), environmental and social issues (pollutant distribution, aquifer characterization).
The PhD project shows results of a study carried out in a multilayer carbonate anticline characterized by different mechanical properties. The aim of this study is to understand the factors which influence the fracture formation and to define their temporal sequence during the folding process.
The studied are is located in the Cingoli anticline (Northern Apennines), which is characterized by a pelagic multilayer characterized by sequences with different mechanical stratigraphies. A multi-scale analysis has been made in several outcrops located in different structural positions.
This project shows that the conceptual sketches proposed in literature and the strain distribution models outline well the geometrical orientation of most of the set of fractures observed in the Cingoli anticline. On the other hand, the present work suggests the relevance of the mechanical stratigraphy in particular controlling the type of fractures formed (e.g. pressure solution seams, joints or shear fractures) and their subsequent evolution.
Through a multi-scale analysis, and on the basis of the temporal relationship between fracture sets and their orientation respect layering, I also suggest a conceptual model for fracture systems formation.Le anticlinali carbonatiche presentano un’intensa fratturazione indotta dalla deformazione durante il piegamento. Caratterizzare e comprendere lo sviluppo dei sistemi di fratture collegati al processo plicativo risulta essere di notevole interesse sia da un punto di vista scientifico che applicativo. I sistemi di fratture forniscono un contributo fondamentale per la comprensione dell’evoluzione cinematica della pieghe, inoltre, la comprensione delle relazioni tra sistemi di fratture e pieghe può contribuire a definire l'evoluzione strutturale dell'area di studio. Da un punto di vista applicativo è ormai noto come i sistemi di fratture incidono enormemente sulla circolazione dei fluidi. Di conseguenza la loro definizione trova un'applicazione importante nel settore energetico (flussi geotermici, stoccaggio gas e CO2, esplorazione petrolifera), ambientale (dispersione di inquinanti nel sottosuolo), e sociale (caratterizzazione degli acquiferi ecc.). La tesi di Dottorato presenta uno studio sull’analisi e la caratterizzazione di sistemi di fratture in un’anticlinale carbonatica caratterizzata da un multistrato con diverse caratteristiche meccaniche. Il progetto di Dottorato si pone l’obiettivo di comprendere i fattori che maggiormente influenzano le proprietà dei sistemi di fratture e di definire la loro evoluzione nel tempo. A tal fine è stata analizzata l’anticlinale di Cingoli (Appennino settentrionale) che espone una serie di interessanti affioramenti in calcari pelagici. Attraverso analisi a diverse scale di osservazione sono stati quindi caratterizzati i sistemi di fratture in affioramenti posizionati lungo tutta l’anticlinale e in diverse posizioni strutturali. Nel lavoro è stato osservato e discusso come la posizione strutturale e soprattutto la stratigrafia meccanica influiscono sulla formazione dei sistemi di fratture. In particolare è stato osservato come i modelli proposti in letteratura sintetizzano e schematizzano bene l’assetto geometrico di alcune fratture osservate a Cingoli. In questo lavoro, però, si è evidenziato come la stratigrafia meccanica ha un ruolo decisivo soprattutto per quanto riguarda la tipologia meccanica di fratture.
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Gill, Benjamin Charles. "High-resolution sulfur isotope records of the Paleozoic and a detailed geochemical study of the late Cambrian SPICE event utilizing sulfur isotope stratigraphy, metal chemistry and numerial modeling". Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=78&did=1871861801&SrchMode=1&sid=1&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270232379&clientId=48051.
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Haines, Peter W. "Carbonate shelf and basin sedimentation, late Proterozoic Wonoka Formation, South Australia /". Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phh152.pdf.
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Bächle, Gregor T. [Verfasser], e Thomas [Akademischer Betreuer] Aigner. "Effects of pore structure on velocity and permeability in carbonate rocks / Gregor T. Bächle ; Betreuer: Thomas Aigner". Tübingen : Universitätsbibliothek Tübingen, 2012. http://d-nb.info/116269999X/34.
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PICO, RUBY LORENA HERNANDEZ. "INFLUENCE OF MICROSTRUCTURE ON MECHANICAL PROPERTIES OF CARBONATE ROCKS USING 3D DIGITAL IMAGES OF X-RAY MICROTOMOGRAPHY". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=23966@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Reservatórios carbonáticos contêm entre 50 e 60 por cento de petróleo e gás do mundo. No entanto, estas rochas têm apresentado problemas operacionais consideráveis durante as etapas de perfuração e produção. Tais problemas são originados pelas dificuldades na caracterização adequada destas rochas em função da complexa distribuição espacial de sua micro e macro estrutura. Enquanto ambas as escalas possuem importância no entendimento do comportamento de carbonatos, o presente trabalho trata da análise da microestrutura. Nesse âmbito, a proposta deste trabalho integra o processamento e análises de imagens digitais adquiridas mediante microtomografia de raios-X, elaboração de malhas de elementos finitos e simulação numérica de forma a prever propriedades elásticas, com o objetivo de correlacionar a microestrutura e o módulo de Young. Foram utilizadas imagens digitais de amostras de afloramento (travertinos) considerados como possíveis análogas a rochas carbonáticas de reservatório. A metodologia implementada permitiu obter sub-amostras que incluem uma gama de microestruturas e porosidades numa única amostra para assim simular numericamente o módulo de Young. Os resultados dos ensaios virtuais foram comparados com os resultados de ensaios reais executados em amostras da mesma rocha e dados encontrados na literatura. A aplicação da metodologia e os resultados obtidos indicam o potencial e as limitações atuais desta técnica. Conclui-se neste estudo que o valor do módulo de Young das amostras simuladas numericamente é afetado pela distribuição espacial, conectividade dos poros e pela microporosidade da rocha. Os valores encontrados no ensaio virtual tendem a serem superiores aos obtidos em ensaios reais devido à dificuldade de inserir, no modelo de micro estrutura, os contatos entre os grãos assim como regiões mais compressíveis não determinadas na aquisição das imagens.
Carbonate reservoirs contain between 50 and 60 per cent of oil and gas in the world. However, these rocks have presented considerable operational problems during drilling and production steps. Such problems are caused by the difficulties in proper characterization of these rocks due the complex spatial distribution of their micro and macrostructure. Although both scales have importance in understanding the behavior of carbonates, the present work deals with the analysis of the microstructure. In this context, the proposal of this work integrates the processing and analysis of digital images acquired by x-ray microtomography, finite element mesh generation and numerical simulations to predict elastic properties in order to correlate the microstructure and the Young s modulus. We used digital images of samples of outcrop (travertine) considered as a possible analogous to carbonate rocks of reservoir. The methodology implemented allowed get sub-samples that include a range of microstructures and porosities in a single sample to determine numerically the Young s modulus. The virtual test results were compared with laboratory test results performed on samples from the same rock and data found in the literature. The application of the methodology and the results obtained indicate the potential and current limitations of this technique. This study concluded that the value of Young s modulus of numerically simulated samples is affected by spatial distribution, pore connectivity and microporosity of these rocks. The values found in the virtual test tend to be higher than those obtained in laboratory tests due to the difficulty of inserting, in the model of micro structure, contacts between the grains as well as more compressible regions not certain on the acquisition of the images.
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Nicolas, Aurélien Pierre. "Comportement mécanique des carbonates peu poreux : étude expérimentale et modélisation micromécanique". Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0040/document.
Testo completoAbstract (sommario):
Avec l’augmentation de la pression de confinement, le comportement mécanique des calcairespasse d’un comportement fragile à un comportement ductile. Le régime fragile estcaractérisé par une compaction élastique suivie d’une dilatance macroscopique due à despropagations de fissures. Lorsque les fissures coalescent, la rupturemacroscopique est reliéeà une chute de contrainte. Le régime ductile est caractérisé par une compaction élastiquesuivie d’une déformation macroscopique diffuse. La déformation est accommodée par uneplasticité intracristalline (dislocations, macles) et/ou une fracturation des grains. L’objectif decette thèse est d’examiner expérimentalement les paramètres influant sur le comportementmécanique des calcaires de porosité intermédiaire et de modéliser ce comportement. Lesexpériences ont été réalisées sur le calcaire de Tavel (porosité de 14.7%)The mechanical behaviour of limestones is brittle at low confining pressure and becomesductile with the increase of the confining pressure. The brittle behaviour is characterisedby a macroscopic dilatancy due to crack propagation, leading to a stress drop when crackscoalesce at failure. The ductile behaviour is characterised by a a diffuse deformation due tointra-crystalline plasticity (dislocation movements and twinning) and microcracking. The aimof this work is to examine the influence of temperature, pore fluid, strain rate, and time onthe mechanical behaviour. Triaxial deformation experiments were performed on white Tavellimestone (porosity 14.7%). The macroscopic behaviour is then modelled.Constant strain rate triaxial deformation experiments and stress-stepping creep experimentswere performed. Elastic wave velocities were inverted in term of axial crack densities. Themechanical behaviour is brittle for constant strain rate deformation experiments performed atPc · 55 MPa. In this case, inelastic deformation is due to cracks propagation. For Pc ¸ 70 MPa,elastic compaction is followed by an inelastic compaction. Porosity collapse is due to intracrystallineplasticity and micro-cracking. After some inelastic compaction, volumetric strainturns to dilatancy because crack nucleate at dislocation pile-ups and their contribution to thestrain becomes predominant compared to plastic pore collapse. In the brittle regime, watersaturationdecreases the differential stress at the onset of crack propagation and enhancesmacroscopic dilatancy. Temperature decreases the confining pressure at the brittle-semibrittle(ductile) transition. A model describing the macroscopic behaviour is derived from (1) a crackpropagation law, (2) a plasticity law for a porous medium, and (3) a law for nucleation of newscracks due to local dislocation pile-ups. The model predicts the volumetric strain, the stresstensor, and the evolution of damage, as a function of applied deformation. Theoretical resultsare in good agreement with experimental observations
44
Salley, Devon Mr. "Advancing Methods to Measure the Atmospheric CO2 Sink from Carbonate Rock Weathering". TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1603.
Testo completoAbstract (sommario):
With rising atmospheric CO2 concentrations, a detailed understanding of processes that impact atmospheric CO2 fluxes is required. While a sink of atmospheric carbon from the continents to the ocean from carbonate mineral weathering is, to some degree, offset by carbonate mineral precipitation in the oceans, efforts are underway to make direct measurements of these fluxes. Measurement of the continental sink has two parts: 1) measurement of the dissolved inorganic carbon (DIC) flux leaving a river basin, and 2) partitioning the inorganic carbon flux between the amount removed from the atmosphere and the portion from the bedrock. This study attempted to improve methods to measure the DIC flux using existing data to estimate the DIC flux from carbonate weathering within the limestone karst region of south central Kentucky. The DIC flux from the Barren River drainage basin upstream from Bowling Green in southern Kentucky and northern Tennessee, and the upper Green River drainage basin, upstream from Greensburg, Kentucky, was measured, each for a year, using U.S.G.S. discharge data and water-chemistry data from municipal water plants. A value of the (DIC) flux, normalized by time and area of carbonate rock, of 4.29 g km-3 day-1 was obtained for the Barren River, and 4.95 kg km-3 for the Green. These compared favorably with data obtained by Osterhoudt (2014) from two nested basins in the upper Green River with values of 5.66 kg km-3 day-1 and 5.82 kg km-3 day-1 upstream from Greensburg and Munfordville, respectively. Additional normalization of the values obtained in this study
by average precipitation minus evapotranspiration over the area of carbonate rock, or water available for carbonate dissolution, resulted in values of 5.61x107 g C (km3 H20)- 1 day-1 (grams of carbon per cubic kilometer of water, per day) for the Barren, and 7.43x107g C (km3 H20)-1 day-1 for the Green River. Furthermore, a statistical relationship between the total DIC flux and time-volume of water available for dissolution has been observed, yielding an r2 value of 0.9478. This relationship indicates that the primary variables affecting DIC flux for these drainage basins are time and the volume of water available for dissolution.
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Shaw, Alexander Iain. "The characterisation of calcrete based on its environmental settings within selected regions of the Kalahari, Southern Africa". Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:3474d9e4-fa10-4bd4-af7e-dcbe9ebad640.
Testo completoAbstract (sommario):
Chemical sediments in a variety of geomorphic environments (pedogenic, fluvial, palustrine, lacustrine and pan) were investigated from seven regions (SW Kalahari, Kgalagadi, Kalkweissrand, Etosha, Linyanti, Okavango and Ngami) in the Kalahari of southern Africa. These primary and multi-phase sediments were characterised by a range of pure and intergrade silcrete, calcrete and dolocrete fabrics which contained an array of structures indicative of the crystalline and biogenic processes responsible for their precipitation, epigenesis and paragenesis. Petrography, mineralogy and isotope geochemistry provided significant insight regarding the environmental and geochemical conditions at the time of precipitation. Petrography indicated that the majority of chemical sediments were undergoing epigenetic modification as a consequence of the desiccation induced transition from phreatic to vadose diagenetic and geochemical conditions. The role of rapidly infiltrating meteoric water, associated with unstable wetting fronts, is believed to be instrumental in vadose diagenesis and the precipitation of crystalline/alpha fabric carbonate. Salinisation within the capillary fringe and deeper vadose zone is believed to be responsible for the sequence dolomitisation of crystalline calcite within mature sequences. Highly saline pan conditions instigate the precipitation of authigenic dolomite, calcite and K-feldspar within the surface sediments and authigenic silica at depth. Phreatic water beneath the islands, floodplains and fluvial systems of the Okavango, which undergoes evapotranspirational and transmission salinisation and ultimately terminal desiccation, are similarly precipitating silcrete. Pedogenic processes principally associated with C4 vegetation are responsible for the gratification of carbonate mud within desiccating lacustrine, palustrine and pan sediments. Within the thin sandy Kalahari soils, pedogenesis is limited, but biogenic/beta fabric precipitation linked to mycorrihizae and tree/shrub savanna vegetation is instrumental in the formation of hardpans and the modification of upper calcrete horizons. The dominance of a distinct assemblage (smectite/kaolinite or sepiolite/palygorskite) of authigenic clay minerals present within all the environments provides evidence of semi-arid precipitation within Mg and Ca enriched saline/rapidly evaporating water or brackish/reduced permeability environments.
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Hoehn, Jack R. "Low-Temperature Deformation of Mixed Siliciclastic & Carbonate Fault Rocks of the Copper Creek, Hunter Valley, and McConnell Thrusts". Oberlin College Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1400002733.
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Abreu, Elita Selmara de. "Modelagens teóricas e empíricas aplicadas à investigação da conexão entre as propriedades petrofísicas e elásticas em rochas carbonáticas". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277090.
Testo completoAbstract (sommario):
Orientadores: Sandro Guedes de Oliveira, Lúcia Duarte DillonDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-17T17:53:23Z (GMT). No. of bitstreams: 1 Abreu_ElitaSelmarade_M.pdf: 3986219 bytes, checksum: 3254aa4fe691af01904819c1fb348ada (MD5) Previous issue date: 2010
Resumo: O principal propósito dessa dissertação é estudar modelos de meio efetivo de física de rochas que conecte as propriedades petrofísicas e as propriedades elásticas, assim como a sua aplicação na investigação dessas propriedades em rochas carbonáticas. Inicialmente será feita uma introdução a alguns modelos de física de rochas para meio efetivo, conhecidos como modelo de Voigt-Reuss-Hill, modelo de Kuster & Toksöz, modelo Diferencial de Meio Efetivo e relação de Gassmann, com objetivo de estabelecer os parâmetros que serão medidos e utilizados no desenvolver do trabalho. Após essa parte introdutória, baseado no modelo de Xu-Payne, foram realizadas uma série de análises de atributos geométricos, como a distribuição de tipos de poros, obtidas através de lâminas petrográficas com intuito de descrever a correlação entre as propriedades petrofísicas e elásticas e assim poder calibrar o modelo teórico utilizado na predição dessas propriedades. Dessa forma, o modelo calibrado passa a desempenhar um papel mais condizente com o sistema poroso da rocha permitindo uma melhor correlação entre os parâmetros elásticos e petrofísicos. Os resultados obtidos mostram que a utilização da informação de lâminas petrográficas, na parametrização do modelo, torna o método mais robusto na predição e conexão das propriedades elásticas e petrofísicas de rochas carbonáticas, tornando confiável a mudança de escala rocha-perfil, bem como possibilitando a predição qualitativa de propriedade permo-porosas a partir da velocidade da rocha
Abstract: The main purpose of this dissertation is to study rock physics effective models that connect the petrophysics and elastic properties as well as its application on the investigation of these properties on carbonate rocks. Firstly, we make an introduction to some rock physics of effective models as: Voig-Reuss-Hill, Kuster&Toksöz, Differential Effective Medium, Gassmann¿s Relation, aiming at establishing the parameters that will be measured and used latter. After this introductory part and based on the Xu-Payne model, several geometric factors analysis was done like pore types distribution, obtained by thin sections, with the intention of describing the correlation between the petrophysics and elastic properties. In this way, the model becomes more compatible with the rock porous medium, allowing a better correlation between the petrophysics and elastic parameters. Our results show that using the thin section information on the model parametrization, the predictability and connectivity of petrophysics and elastic properties applied to carbonate rocks become more robust, making trustable the upscale rock-well log and also enabling the permo-porosity properties prediction, in a qualitative way, through the velocity measurements
Mestrado
Física
Mestra em Física
48
Smith, Stuart A. "The phanerozoic basin-fill history of the Roebuck Basin /". Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phs6615.pdf.
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Dunster, John N. "Sedimentology of the Ouldburra Formation (Early Cambrian), northeastern Officer Basin". Title page, contents and abstract only, 1987. http://web4.library.adelaide.edu.au/theses/09SM/09smd926.pdf.
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Voegelin, Andrea. "The molybdenum isotopic composition of carbonate rocks : setup of a novel paleo-redox proxy and its application to geological problems /". [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000288146.
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