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Detailed understanding of sediment architecture is crucial for planning well placements and minimizing bypassed oil in low net-to-gross fluvial successions (those with a high proportion of mudstones and siltstones). Field development planning relies greatly on architectural models. These, in turn, are dependent on obtaining an adequate description of the subsurface and accurate interpretation of the fluvial style. But this is difficult due to the limited quantity of data available. Inevitably, therefore, the models are biased by preconceptions and assumptions. For low net-to-gross fluvial succession, the common presumption is that they are the products of high-sinuosity rivers, because of the high proportion of mudstone present. This choice drives the selection of parameters of reservoir modelling. Comprehensive architectural analysis of the well-exposed Wasatch Formation (Late Paleocene to Early Eocene) in the SE part of the Piceance Basin, in western Colorado, USA, shows this presumption to be an unsafe choice. The upper part of this formation (the Shire Member) is almost entirely the product of straight rivers. Evidence of high-sinuosity rivers is distinctly lacking, with just a single example found of point-bar deposits, and even that is laterally restricted and weakly developed. The bulk of the member, which is over 200m in thickness, is composed of mudstones showing pedogenic alteration of a wide range of intensities, and with evidence of both poorly and well drained soils. Isolated within these mudstones are narrow ribbon sandstones, up to 30m wide and 3m thick, interpreted to be the product of low-sinuosity single-thread (anastsomosed) rivers. At intervals through the succession are a small number of sheet sandstones up to 1km wide and 12m thick. These sheets are an amalgamation of downstream-accreting bars, some of them gravely, and channel-fill deposits, and are interpreted to be the product of a low-sinuosity but multi-threaded (braided) river. The predominance in the succession of mudstone, of relatively high cohesive strength, suggests at first sight conditions favourable for the development of high-sinuosity rivers.

>Magister Scientiae - MSc / This study investigates the viability of the sedimentary deposits in the Northern Orange basin for carbon storage and sequestration. A combination of geological modelling, petrographic and geochemical techniques are used to investigate this scenario after an initial seismic-well tie had been performed to match the formation tops in Well AF-1 with the 3D seismic volume acquired in this basin in 2009. Core description of well AF-1 assisted in identifying different facies and samples taken at specific depths for petrographic and geochemical analyses, while different geological formations were mapped from the calibrated positions of seismic-well tie throughout the seismic volume. The well data and geophysical logs were utilized to generate petrophysical properties and used to calibrate observations made from seismic interpretations. The facies log used in this study was generated using the Python’s script on Petrel 2014 Gamma Ray, while the density log was used to generate the porosity log. The generated facies and porosity logs were upscaled and used to populate a 3D grid using faults and surfaces identified in the seismic volume. The sedimentological properties of the subsurface were identified utilizing petrographic descriptions including measurements of sorting, colour and grain sizes. While the mineralogical properties of the record was verified through XRD analyses and thin section. The facies and porosity modelling revealed the dominance of siltstones and sandstones as the main sedimentary facies throughout the sequence. Sandstones are extensive and prominent within the Cenozoic and Mastrichtian, while the unit dated to the Barremian is identified as having the best potential for CO2 storage based on the overlaying capping unit. Quartz, Plagioclase feldspar (Albite), Biotite and Kaolinite are the major minerals identified in all four samples. Each of these minerals has an implication for which may influence the long term storage of CO2 with the potential to form as they may form part of the inra-porous post-depositional cementation and hence change the porosity and permeability properties. The presence of Albite as observed on the XRD may predict possible mineralisation of CO2 to form Dawsonite when reservoir is injected with CO2. The Barremian sandstone which straddles the Aptian shale at the top and the Hauterivian Shale and Siltsone deposit at the bottom holds a good promise for a potential CO2 storage. An estimated volume of CO2 that could be stored in the reservoir of the Barremian sandstone in zone 8 is limited to the lateral seal of shale above the reservoir in zone 7 of the Aptian age. The method used to determine the potential storage capacity of CO2 was performed by Alexandros Tasianas and Nikolaos Koukouzas (2016). The Equation used to determine CO2 storage capacity is: mCO2 = RV * Ø * Sg * δ(CO2) . / 2021-09-01

Submitted by Maria Eneide de Souza Araujo (mearaujo@ipen.br) on 2017-03-10T16:25:16Z No. of bitstreams: 0 / Made available in DSpace on 2017-03-10T16:25:16Z (GMT). No. of bitstreams: 0 / O Pantanal da Nhecolândia, localizado no estado do Mato Grosso do Sul, é parte do Pantanal Brasileiro e possui características específicas, dentre elas a existência de lagos salinos, comumente conhecidos como Salinas. Para se estimar uma possível influência humana no Pantanal da Nhecolândia quatro perfis de sedimento foram coletados, em 2010, nas Salinas A, 6, M e V com o objetivo de se fazer a caracterização química inorgânica dos sedimentos determinando os elementos As, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb e Zn pela técnica de análise por ativação com nêutrons instrumental nas frações fina (silte + argila) e grossa (areia média + areia fina) do sedimento e também determinar as taxas de sedimentação e idade do sedimento pelo método do 210Pb. Para auxiliar na interpretação dos resultados determinou-se a composição granulométrica e o conteúdo de água das amostras de sedimento. A análise granulométrica indicou que as Salinas possuem um percentual da fração fina oscilando entre 3,5 % na Salina M a 70 % na Salina A, o que é característico dessa região. Os quatro perfis de sedimento apresentaram diferentes taxas de sedimentação, o que está provavelmente relacionado aos períodos de seca e enchentes. Os resultados obtidos de concentração dos elementos químicos foram comparados com os valores da Upper Continental Crust UCC e da North American Shale Composite NASC, e alguns elementos, como As, Hf, Rb e Sb, apresentaram valores acima destes nas duas frações granulométricas do sedimento, sugereindo à existência de depósitos naturais destes elementos nas quatro Salinas estudadas. Os resultados de concentração dos elementos estudados indicam a não existência de influência antrópica na região. Calculou-se também o fator de enriquecimento - FE dos elementos químicos usando como valores de referência os valores da UCC, NASC, e os valores da base do perfil-FEB, concluindo-se que o FEB foi a melhor metodologia para se avaliar o enriquecimento dos elementos. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Este trabalho caracterizou os siltitos do Grupo Itararé, rocha branda proveniente da amostragem de pedreira localizada nas proximidades de futuro empreendimento brasileiro, o Trem de Alta Velocidade. Objetivou entender as causas da pronunciada e rápida alteração da rocha intacta, e simular, em condições controladas de laboratório, a degradação hidromecânica causada pela simples variação da umidade relativa do ar. Para tal, estabeleceu-se técnica de amostragem de testemunhos por meio da extração via seca com ar-comprimido, e processo de intemperismo artificial, composto por 4 ciclos de 2 etapas (secagem e umedecimento). O processo se deu em dessecadores, sendo a variação da umidade ocasionada pela técnica do vapor e sílica gel. O acompanhamento da degradação dos corpos de prova efetuou-se com duas técnicas não-destrutivas de propagação de ondas: o pulso ultrassônico e a excitação por impulso (sistema Sonelastic). Em paralelo, realizou-se a caracterização geotécnica dos siltitos em umidade natural, com ensaios mineralógicos, físicos, físico-mecânicos, físico-químicos e de alteração laboratorial. Por meio desta metodologia, foi possível estimar as minorações do módulo de deformabilidade e da resistência, além das causas físico-químicas da degradação. / This work characterized the siltstones of the Itararé Group, a soft rock sampled in a quarry located near a future Brazilian venture, the High Speed Train. It aims at understanding the causes of the pronounced and fast changes of the intact rock, and simulate in controlled laboratory conditions the hydro degradation process caused by simple variation of relative air humidity. Dry sampling technique with compressed air was used to extract samples from blocks, and the process of artificial weathering consisted on 4 cycles of 2 steps (drying and wetting). The process occurred in desiccators, where moisture variation was caused by the vapor technique and silica gel. The monitoring of the specimens degradation was performed with two non-destructive wave propagation techniques: the ultrasonic pulse and the impulse excitation (Sonelastic system). A geotechnical characterization of the siltstones in natural moisture condition was made in parallel, consisting on mineralogical, physical, physical-mechanical, physical-chemical and durability tests. By this methodology, it was possible to estimate the mitigation of the deformability modulus and strength besides the physical- chemical causes of degradation.

Este trabalho caracterizou os siltitos do Grupo Itararé, rocha branda proveniente da amostragem de pedreira localizada nas proximidades de futuro empreendimento brasileiro, o Trem de Alta Velocidade. Objetivou entender as causas da pronunciada e rápida alteração da rocha intacta, e simular, em condições controladas de laboratório, a degradação hidromecânica causada pela simples variação da umidade relativa do ar. Para tal, estabeleceu-se técnica de amostragem de testemunhos por meio da extração via seca com ar-comprimido, e processo de intemperismo artificial, composto por 4 ciclos de 2 etapas (secagem e umedecimento). O processo se deu em dessecadores, sendo a variação da umidade ocasionada pela técnica do vapor e sílica gel. O acompanhamento da degradação dos corpos de prova efetuou-se com duas técnicas não-destrutivas de propagação de ondas: o pulso ultrassônico e a excitação por impulso (sistema Sonelastic). Em paralelo, realizou-se a caracterização geotécnica dos siltitos em umidade natural, com ensaios mineralógicos, físicos, físico-mecânicos, físico-químicos e de alteração laboratorial. Por meio desta metodologia, foi possível estimar as minorações do módulo de deformabilidade e da resistência, além das causas físico-químicas da degradação. / This work characterized the siltstones of the Itararé Group, a soft rock sampled in a quarry located near a future Brazilian venture, the High Speed Train. It aims at understanding the causes of the pronounced and fast changes of the intact rock, and simulate in controlled laboratory conditions the hydro degradation process caused by simple variation of relative air humidity. Dry sampling technique with compressed air was used to extract samples from blocks, and the process of artificial weathering consisted on 4 cycles of 2 steps (drying and wetting). The process occurred in desiccators, where moisture variation was caused by the vapor technique and silica gel. The monitoring of the specimens degradation was performed with two non-destructive wave propagation techniques: the ultrasonic pulse and the impulse excitation (Sonelastic system). A geotechnical characterization of the siltstones in natural moisture condition was made in parallel, consisting on mineralogical, physical, physical-mechanical, physical-chemical and durability tests. By this methodology, it was possible to estimate the mitigation of the deformability modulus and strength besides the physical- chemical causes of degradation.