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Estudo do processo de acidificação de rochas reservatório por meio de RMN e microtomografia de raios-X / Study of reservoir rocks acidification process by NMR and X-ray microtomographyPolli, Roberson Saraiva 26 February 2016 (has links)
Nos estudos de meios porosos, tais como em rochas reservatório, a RMN exerce um papel fundamental, em especial quando se trata da indústria petrolífera, sendo uma das ferramentas fundamentais utilizadas em perfis de poços. De forma geral, obtêm-se informações como tempos de relaxação transversal (T2) e coeficientes de difusão, permitindo inferir propriedades tais como permeabilidade e distribuição de tamanhos de poros. Outra forma de analisar os fluidos em amostras porosas é com o uso de técnicas de imagens, em que se enquadram a de Imagens por Ressonância Magnética (IRM) e as de microtomografia computadorizada (μCT). O presente trabalho teve como objetivo a obtenção de metodologias de análise de técnicas de estimulação de poços, visando um melhor entendimento dos processos de acidificação com formação de caminhos preferenciais denominados wormholes em rochas carbonáticas de afloramento e reservatório. Como objetivo secundário, o desenvolvimento de um sistema de IRM, contemplando os conjuntos de bobinas de gradiente, bobinas de rf e filtros analógicos. O processo de acidificação foi estudado através de medidas morfológicas de dimensão fractal, comprimento de caminho principal e volume dos wormholes extraídas de imagens por μCT, enquanto as conexões entre regiões de porosidade original e o wormhole foram estudadas com a obtenção de distribuições de tempo de relaxação T2 durante um processo de secagem à vácuo. As medidas de secagem permitiram observar o comportamento de regiões distintas: água livre, água com restrição de mobilidade por capilaridade e água ligada à argila. Durante a secagem, embora a água ligada à argila não pôde ser retirada, o comportamento foi o esperado com a água livre, sendo seca primeiro, seguido da água com menor mobilidade por capilaridade. Não é de nosso conhecimento que haja algum método de secagem de amostra por meio unicamente de vácuo, principalmente em aplicações em geologia. De maneira geral, os resultados mostraram que, excluído a dimensão fractal, as outras medidas como o T2 médio, comprimento do caminho principal e padrão de secagem não possuem diferença de acordo com a geologia da rocha estudada. No entanto, para as rochas carbonáticas padrão (Indianas) o valor da dimensão fractal foi de 1,6, assemelhando sua morfologia a uma estrutura bidimensional. Para as rochas reservatório, a dimensão fractal foi maior que 1,9, coerente com sua forma tridimensional e maiores ramificações. No que concerne à instrumentação, apresentamos as etapas necessárias à adaptação de um sistema de espectroscopia e relaxometria em um sistema de imagens, gerando a imagem de um phantom. O aprimoramento deste sistema será de grande utilidade para o estudo de meios porosos com técnicas de imagens convencionais e específicas ao problema, o que se mostrou de grande importância para o estudo de wormholes. Este trabalho apresentou outras formas de análise do wormhole com resultados satisfatórios que podem ser associados as técnicas mais difundidas na literatura. / In studies of porous media such as reservoir rocks, Nuclear Magnetic Resonance (NMR) plays a key role, especially when it comes to the oil industry, as one of the fundamental tools used in well logs. In general, obtains informations such as transverse relaxation time (T2), and diffusion coefficients, allowing inferring properties such as permeability and poring size distribution. Another way of analyzing fluids in porous media is using imaging techniques, in which fit the Magnetic Resonance Imaging (MRI) and computed microtomography (μCT). This study aimed to obtain methods of analysis of well stimulation techniques, aiming at a better understanding of the acidification processes with formation of preferential pathways called wormholes in outcrop and reservoir carbonate rocks. As a secondary objective, there is the development of an MRI system, comprising sets of gradient coils, RF coils and analog filters. The acidification process was studied by measurements of morphological fractal dimension, the main path length and volume of wormholes pictures extracted by μCT, while the connections between regions of the original porosity and wormhole were studied by the T2 time distributions during a drying process in vacuum. Drying measures allowed observing the behavior of distinct regions: free water, capillary bound water and clay bound water. During drying, although the most trapped water could not be removed, the performance was expected with free water, being dried first, followed by the water trapped by capillarity. It is our knowledge that there is no drying method by vacuum alone, especially in applications in geology. In general, the results show that, excluding the fractal dimension, other measures such as the T2 mean, primary drying path length and volume have no difference pattern according to the geology of the rock studied. However, for the standard carbonate rocks (Indiana) the value of the fractal dimension was 1.6, similar morphology to a two-dimensional structure. For the reservoir rocks, the fractal dimension was greater than 1.9, consistent with its three-dimensional shape and larger branches. Concerning the instrumentation, we present the steps necessary to adapt a spectroscopy and relaxometry system in an imaging system, obtaining the image of a phantom. The improvement of this system will be very useful for the study of porous media with conventional and specific imaging techniques to the problem, which proved of great importance for the study of wormholes. This work presented other forms of wormhole analysis with satisfactory results that may be associated with the most widespread techniques in the literature.
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Relationship between pore geometry, measured by petrographic image analysis, and pore-throat geometry, calculated from capillary pressure, as a means to predict reservoir performance in secondary recovery programs for carbonate reservoirs.Dicus, Christina Marie 15 May 2009 (has links)
The purpose of this study was first to develop a method by which a detailed
porosity classification system could be utilized to understand the relationship between
pore/pore-throat geometry, genetic porosity type, and facies. Additionally, this study
investigated the relationships between pore/pore-throat geometry, petrophysical
parameters, and reservoir performance characteristics. This study focused on the
Jurassic Smackover reservoir rocks of Grayson field, Columbia County, Arkansas.
This three part study developed an adapted genetic carbonate pore type
classification system, through which the Grayson reservoir rocks were uniquely
categorized by a percent-factor, describing the effect of diagenetic events on the
preservation of original depositional texture, and a second factor describing if the most
significant diagenetic event resulted in porosity enhancement or reduction. The second
part used petrographic image analysis and mercury-injection capillary pressure tests to
calculate pore/pore-throat sizes. From these data sets pore/pore-throat sizes were
compared to facies, pore type, and each other showing that pore-throat size is controlled by pore type and that pore size is controlled primarily by facies. When compared with
each other, a pore size range can be estimated if the pore type and the median pore-throat
aperture are known.
Capillary pressure data was also used to understand the behavior of the
dependent rock properties (porosity, permeability, and wettability), and it was
determined that size-reduced samples, regardless of facies, tend to show similar
dependent rock property behavior, but size-enhanced samples show dispersion. Finally,
capillary pressure data was used to understand fluid flow behavior of pore types and
facies. Oncolitic grainstone samples show unpredictable fluid flow behavior compared
to oolitic grainstone samples, yet oncolitic grainstone samples will move a higher
percentage of fluid. Size-enhanced samples showed heterogeneous fluid flow behavior
while the size-reduced samples could be grouped by the number of modes of pore-throat
sizes.
Finally, this study utilized petrographic image analysis to determine if 2-
dimensional porosity values could be calculated and compared to porosity values from
3-dimensional porosity techniques. The complex, heterogeneous pore network found in
the Grayson reservoir rocks prevents the use of petrographic image analysis as a porosity
calculation technique.
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Relationship between pore geometry, measured by petrographic image analysis, and pore-throat geometry, calculated from capillary pressure, as a means to predict reservoir performance in secondary recovery programs for carbonate reservoirs.Dicus, Christina Marie 10 October 2008 (has links)
The purpose of this study was first to develop a method by which a detailed
porosity classification system could be utilized to understand the relationship between
pore/pore-throat geometry, genetic porosity type, and facies. Additionally, this study
investigated the relationships between pore/pore-throat geometry, petrophysical
parameters, and reservoir performance characteristics. This study focused on the
Jurassic Smackover reservoir rocks of Grayson field, Columbia County, Arkansas.
This three part study developed an adapted genetic carbonate pore type
classification system, through which the Grayson reservoir rocks were uniquely
categorized by a percent-factor, describing the effect of diagenetic events on the
preservation of original depositional texture, and a second factor describing if the most
significant diagenetic event resulted in porosity enhancement or reduction. The second
part used petrographic image analysis and mercury-injection capillary pressure tests to
calculate pore/pore-throat sizes. From these data sets pore/pore-throat sizes were
compared to facies, pore type, and each other showing that pore-throat size is controlled by pore type and that pore size is controlled primarily by facies. When compared with
each other, a pore size range can be estimated if the pore type and the median pore-throat
aperture are known.
Capillary pressure data was also used to understand the behavior of the
dependent rock properties (porosity, permeability, and wettability), and it was
determined that size-reduced samples, regardless of facies, tend to show similar
dependent rock property behavior, but size-enhanced samples show dispersion. Finally,
capillary pressure data was used to understand fluid flow behavior of pore types and
facies. Oncolitic grainstone samples show unpredictable fluid flow behavior compared
to oolitic grainstone samples, yet oncolitic grainstone samples will move a higher
percentage of fluid. Size-enhanced samples showed heterogeneous fluid flow behavior
while the size-reduced samples could be grouped by the number of modes of pore-throat
sizes.
Finally, this study utilized petrographic image analysis to determine if 2-
dimensional porosity values could be calculated and compared to porosity values from
3-dimensional porosity techniques. The complex, heterogeneous pore network found in
the Grayson reservoir rocks prevents the use of petrographic image analysis as a porosity
calculation technique.
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Integrated geological and petrophysical investigation on carbonate rocks of the middle early to late early Canyon high frequency sequence in the Northern Platform area of the SACROC UnitIsdiken, Batur 18 February 2014 (has links)
The SACROC unit is an isolated carbonate platform style of reservoir that typifies a peak icehouse system. Icehouse carbonate platforms are one of the least well understood and documented carbonate reservoir styles due to the reservoir heterogeneities they embody. The current study is an attempt to recognize carbonate rock types defined based on rock fabrics by integrating log and core based petrophysical analysis in high-frequency cycle (HFC) scale sequence stratigraphic framework and to improve our ability to understand static and dynamic petrophysical properties of these reservoir rock types, and there by, improve our understanding of heterogeneity in the middle early to late early Canyon (Canyon 2) high frequency sequence (HFS) in the Northern Platform of the SACROC Unit. Based on core descriptions, four different sub-tidal depositional facies were defined in the Canyon 2 HFS. Identified depositional facies were grouped into three different reservoir rock types in respect to their rock fabrics in order for the HFC scale petrophysical reservoir rock type characteristic analysis. Composed of succession of the identified reservoir rocks, twenty different HFCs were determined within the HFC scale sequence stratigraphic framework. The overall trend in the HFCs demonstrate systematic coarsening upward cycles with high reservoir quality at the cycle tops and low reservoir quality at the cycle bottoms. It was observed in terms of systems tracts described within the cycle scale frame work that the overall stacking pattern for high stand systems tracts (HST) and transgressive systems tracts (TST) is aggradational. And, the reservoir rocks representing the HST are more porous and permeable than those of TST. In addition to that, it was detected that the diagenetic overprint on the HST reservoir rocks is more than that of the TST. According to the overall petrophysical observations, the grain-dominated packstone deposited during HST was interpreted as the best reservoir rock. Upon well log analysis on the identified reservoir rocks, some specific log responses were attributed to the identified reservoir rocks as their characteristic log signatures. / text
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Bioturbation and Resource Quality: A Case Study from the Upper Cretaceous Lysing and Nise Formations, Ellida and Midnatsoll Fields, Norwegian SeaPolo, Camilo Unknown Date
No description available.
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Determination Of Flow Units For Carbonate Reservoirs By Petrophysical - Based MethodsYildirim Akbas, Ceylan 01 October 2005 (has links) (PDF)
Characterization of carbonate reservoirs by flow units is a practical way of reservoir zonation. This study represents a petrophysical-based method that uses well loggings and core plug data to delineate flow units within the most productive carbonate reservoir of Derdere Formation in Y field, Southeast Turkey.
Derdere Formation is composed of limestones and dolomites. Logs from the 5 wells are the starting point for the reservoir characterization. The general geologic framework obtained from the logs point out for discriminations within the formation. 58 representative core plug data from 4 different wells are utilized to better understand the petrophysical framework of the formation. The plots correlating petrophysical parameters and the frequency histograms suggest the presence of distinctive reservoir trends. These discriminations are also represented in Winland porosity-permeability crossplots resulted in clusters for different port-sizes that are responsible for different flow characteristics. Although the correlation between core plug porosity and air permeability yields a good correlation coefficient, the formation has to be studied within units due to differences in port-sizes and reservoir process speed.
Linear regression and multiple regression analyses are used for the study of each unit. The results are performed using STATGRAPH Version Plus 5.1 statistical software. The permeability models are constructed and their reliabilities are compared by the regression coefficients for predictions in un-cored sections.
As a result of this study, 4 different units are determined in the Derdere Formation by using well logging data, and core plug analyses with the help of geostatistical methods. The predicted permeabilities for each unit show good correlations with the calculated ones from core plugs. Highly reliable future estimations can be based on the derived methods.
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Estimação de propriedades petrofísicas de rochas sedimentares a partir de imagens microtomográficas de raíos-x.PORTO, Adriana Lemos. 24 January 2018 (has links)
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Previous issue date: 2015-08-25 / CNPq / Uma técnica inovadora atualmente em desenvolvimento é a construção de modelos digitais a partir de um conjunto de imagens de tomografia de raios-X de alta resolução adquiridas em amostras de rocha. Essa técnica permite definir a geometria 3D do espaço poroso e dos grãos minerais, bem como o reconhecimento dos minerais presentes na rocha. O objetivo desta pesquisa é estimar as propriedades petrofísicas (distribuição granulométrica, composição mineral, porosidade, permeabilidade e velocidade de propagação da onda P) de rochas sedimentares a partir de imagens de microtomografia de raios-X. Neste trabalho são analisadas cinco amostras de arenito (A4, A7, A9, AM10H e AM14V), uma de folhelho (F9), uma de calcário (carbonato Rosário) e duas de Tufa carbonática (Tufa CR e Tufa FG). Quantificou-se a proporção de finos presentes nas amostras, cuja precisão foi dependente da resolução das imagens analisadas. Neste trabalho propõe-se um novo método para a análise da composição mineral a partir de imagens microtomográficas. Os resultados alcançados para a simulação da composição mineral indicam que as amostras de arenito possuem aproximadamente a mesma composição mineral, a amostra de folhelho apresenta uma composição essencialmente silto-argilosa, e que as amostras carbonáticas são formadas essencialmente por calcita e dolomita. De um modo geral, os resultados de DRX confirmaram a composição mineral indicada pela microtomografia. Verificou-se uma relação aproximadamente linear entre os valores de porosidade medidos nos plugues e aqueles determinados por simulação das imagens microtomográficas. A permeabilidade estimada apresentou valores compatíveis com as permeabilidades medidas em laboratório, exceto para a amostra de folhelho e para a amostra de Tufa CR. Para o caso de amostras que possuem uma composição aproximadamente monominerálica, a simulação da onda acústica apresentou excelentes resultados quando comparados com as velocidades fisicamente medidas. Já para o caso das amostras de rocha que apresentam composição multiminerálica, a geração do modelo não considerou as diferentes fases que compõem a matriz mineral, resultando em velocidades simuladas muito acima das velocidades medidas. / An innovative technique currently under development is the construction of digital templates from a set of X-ray tomography, high-resolution images acquired in rock samples. This technique allows to define the 3D geometry of the pore space and mineral grains, as well as recognition of the minerals present in the rock. The objective of this research is to estimate the petrophysical properties (grain size distribution, mineral composition, porosity, permeability and P wave velocity) of sedimentary rocks from microtomography X-ray images. This work analyzed five samples of sandstone (A4, A7, A9, AM10H and AM14V), one of shale (F9), another of limestone (Carbonato Rosário) and two samples of carbonatic Tufa (Tufa CR and Tufa FG). Regarding the particle size distribution is possible to quantify the proportion of fines present in the samples, but such concentrations may be changed according to the resolution of the images analyzed. In this work we propose a new method for the analysis of mineral composition from microCT images. The results obtained for the simulations indicate that the mineral composition of the sandstone samples have approximately the same mineral composition, with different proportions of quartz and clay. Shale sample has an essentially clay composition and the carbonate samples are essentially formed by calcite and dolomite. DRX analyses have proved the mineral composition indicated by microCT analysis. In general, it is observed an approximately linear relationship between porosity values measured in the plugs and those determined by simulation of microCT images. The numerical simulation resulted in values of permeability compatible with permeabilities measured in the laboratory, except for the shale sample and for the Tufa CR sample. For the case of samples having an approximately monomineralic composition, acoustic velocity simulations showed excellent results compared with the physically measured velocities. But for the case of multimineralic rock samples the model generation not considered the different phases making up the mineral matrix, which resulted in simulated velocities far above the measured velocities.
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Caractérisation des hétérogénéités sédimentaires et pétrophysiques d’un réservoir carbonaté microporeux : le cas de la Craie (Crétacé supérieur, Bassin de Paris) / Characterisation of sedimentary and petrophysical heterogeneities of a microporous reservoir : the case of Chalk (Upper Cretaceous, Paris Basin, France)Saïag, Jessica 14 December 2016 (has links)
La craie est définie comme étant une roche carbonatée microporeuse. Cette formation est largement exploitée en Mer du Nord pour ses hydrocarbures et constitue un aquifère dans le Bassin de Paris. Les propriétés réservoirs de la Craie (propriétés matricielles) varient considérablement comme Alam et al. (2011) le soulignent pour les craies de surface et de subsurface de Mer du Nord, avec des porosités de 4 à 52 %, des perméabilités de 0,01 à 100 mD et des vitesses des ondes P sur roche saturée de 2,4 à 4,4 km.s-1.Dans le secteur d'étude (Normandie, France), pris comme analogue de terrain, 114 échantillons (Cénomanien- Santonien) ont été prélevés dans le but d'illustrer l'hétérogénéité sédimentaire et pétrophysique de la Craie. Comme en Mer du Nord, les échantillons présentent une grande variabilité des propriétés pétrophysiques : porosités () de 6,1 à 46,5 %, perméabilités matricielles (K) très faibles (0,002 mD) jusqu’à des perméabilités atypiques et très fortes (470 mD, en l’absence de fractures) et des vitesses des ondes P sur échantillon saturé s'étalant selon une gamme très étendue (1,8 à 5,5 km.s-1). Cependant, l’origine de ces hétérogénéités est encore mal comprise. L'objectif de cette étude est donc de comprendre l’influence respective des facteurs contrôlant les propriétés pétrophysiques afin d'optimiser la modélisation de ce type de réservoir.Trois modèles sédimentaires ont ici été définis avec :(1) un modèle de rampes, subdivisé en modèle de rampe argileuse avec des porosités de 34,4 à 46,5 % et des valeurs de perméabilité de 0,02 à 3 mD, et en modèle de rampe carbonatée (mudstone à grainstone) avec des porosités de 26,1 à 46,5 % et des valeurs de perméabilité de 0,04 à 6 mD,(2) un modèle de contourite (mudstone à grainstone et micro-packstone) avec des porosités de 8,3 à 45,5 % et des valeurs de perméabilité de 0,05 à 477 mD,(3) un modèle de surface de hiatus (Soupground à Hardground) avec des porosités de 6 à 36,9 % et des valeurs de perméabilité de 0,002 à 36 mD.Une classification des microtextures, basée sur l’observation au MEB de quatre critères (contenu minéralogique, fraction biogénique, fraction micritique et fraction de ciment), est proposée. À partir de ces critères, deux groupes majeurs ont été définis avec les Pure chalk microtextures et Impure chalk microtextures. Le groupe des Pure chalk microtextures reflète l’intensité des modifications subies par la craie lors de la diagenèse (taux de diagenèse qu’elle soit précoce ou tardive). Une augmentation du taux de diagenèse induit une diminution de la porosité et une augmentation des vitesses de propagation des ondes acoustiques P. En effet, les transformations qui s’opèrent au cours de la diagenèse, d’une part, réduisent la taille des espaces intergranulaires et donc font diminuer la porosité, et d’autre part, renforcent les contacts entre grains, favorisant ainsi la propagation des ondes acoustiques. Pour le groupe des Impure chalk microtextures, la présence de particules insolubles dans la matrice n’affecte pas la porosité, mais diminue la perméabilité du fait de la réduction des tailles d’accès aux pores.Par conséquent, l’héritage sédimentaire et les transformations diagénétiques, qui affectent à différents degrés les faciès sédimentaires primaires, déterminent les propriétés réservoirs et sont donc la cause de la grande variabilité de ces dernières. De plus, la répartition spatiale de ces microtextures, dépendante des conditions de dépôt (e.g. climat, distance des côtes), et des modifications diagénétiques (précoces ou tardives), n’est pas aléatoire. À partir de l’extrapolation combinée des faciès et de l’empreinte diagénétique, il serait ainsi possible de visualiser la distribution des propriétés pétrophysiques sur les falaises, et donc de visualiser l'architecture des réservoirs dans la Craie. / Chalk is defined as a microporous reservoir rock. This formation is a prolific hydrocarbon-bearing reservoir in the North Sea and is one of the main aquifers in the Paris Basin. The heterogeneity of chalk in terms of petrophysical properties (both surface and subsurface) is illustrated by porosity ranging from 4 to 52 %, permeability from 0.01 to 100 mD, and P-wave velocity on water-saturated samples from 2.4 to 4.4 km.s-1 (Alam et al., 2011).In the study area (Normandie, France), taken as an outcrop analogue, 114 samples were collected (Cenomanian – Santonian). As in the North Sea fields, these samples show great petrophysical heterogeneity: total porosity () from 6.1 to 46.5 %, very low permeability (K; 0.002 mD) to atypical high permeability (477 mD; without fractures), and P-wave velocity on water-saturated samples ranging from 1.8 to 5.5 km.s-1. However, the origin(s) of this large variation in petrophysical parameters is poorly understood. Three sedimentary models are defined here for the chalk:(1) Ramp models, subdivided into argillaceous ramp model, with porosity from 34,4 to 46.5%, and permeability from 0.02 to 3 mD, and carbonate ramp model (mudstone to packstone), with porosity from 26.1 to 46.5%, and permeability from 0.04 to 6 mD,(2) Contourite model (mudstone to grainstone and micro-packstone), with porosity from 8.3 to 45.5%, and permeability from 0.05 to 477 mD,(3) Softground to Hardground model, with porosity from 6 to 36.9%, and permeability from 0.002 to 36 mD.Each model has specific distribution in the porosity-permeability plot.A microtexture classification of the chalk is proposed, based on SEM observation of four groups of criteria (mineralogical content, biogenic fraction, micritic fraction and cement fraction). From these criteria, two major groups are defined: Pure chalk microtexture and Impure chalk microtexture. The Pure chalk microtexture group reflects the intensity of chalk modification during diagenesis (rate of diagenesis, whether early stage or not). An increase in the diagenetic rate induces a decrease in porosity and an increase in P-wave velocity. Diagenetic transformation induces a decrease in pore-space size, with better grain contact, explaining the decrease in porosity and the improved propagation of acoustic P-wave velocity. For Impure chalk microtexture group, the presence of insoluble particles in the matrix does not affect porosity but decreases permeability, due to the reduction of pore-throat size.The complex relationships between depositional inheritance and diagenetic transformation lead to variability in chalk petrophysical parameters. Spatio-temporal distribution of depositional facies and associated diagenetic transformation is not random; it depends on sedimentological condition (e.g. climate and distance to shore) and imprint of diagenetic processes (early or late stage). By extrapolating from the combined data on facies and diagenesis, the petrophysical properties of the entire cliff section can be characterised, and used to describe the reservoir architecture of the Chalk.
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Controls on the distribution of gas hydrates in sedimentary basinsPaganoni, Matteo January 2017 (has links)
Natural gas hydrates store a substantial portion of the Earth's organic carbon, although their occurrence is restricted by thermobaric boundaries and the availability of methane-rich fluids. The complexity of geological systems and the multiphase flow processes promoting hydrate formation can result in a mismatch between the predicted and the observed hydrate distribution. The purpose of this research is to achieve a better comprehension of the factors that influence the distribution of gas hydrates and the mechanism of fluid movements beneath and across the gas hydrate stability zone (GHSZ). Therefore, this study integrates seismic, petrophysical and geochemical data from different gas hydrate provinces. This work provides evidence that hydrates can occur below bottom-simulating reflectors, in the presence of sourcing thermogenic hydrocarbons. The relationship between fluid-escape pipes and gas hydrates is further explored, and pipe-like features are suggested to host a significant volume of hydrates. The host lithology also represents a critical factor influencing hydrate and free gas distribution and, in evaluating a natural gas hydrate system, needs to be considered in conjunction with the spatial variability in the methane supply. The three-dimensional distribution of gas hydrate deposits in coarse-grained sediments, representing the current target for hydrate exploration, is shown to be correlated with that of the underlying free gas zone, reflecting sourcing mechanisms dominated by a long-range advection. In such systems, the free gas invasion into the GHSZ appears controlled by the competition between overpressure and sealing capacity of the gas hydrate-bearing sediments. Globally, the thickness of the free gas zones is regulated by the methane supply and by different multi-phase flow processes, including fracturing, capillary invasion and possibly diffusion. In conclusion, this research indicates that geological, fluid flow and stability factors interweave at multiple scales in natural gas hydrate systems.
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Determinação das constantes elásticas estáticas e dinâmicas das rochas da formação sousa, Bacia do Rio do Peixe, PB. / Determination of static and dynamics elastic constants, of rocks from sousa formation, Rio do Peixe basin, PB.SANTIAGO, Karina Felícia Fischer Lima. 17 April 2018 (has links)
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KARINA FELÍCIA FISCHER LIMA SANTIAGO – DISSERTAÇÃO (PPGEPM) 2015.pdf: 11955651 bytes, checksum: ed2b0ddfd6604f59ef01965e640d37ac (MD5)
Previous issue date: 2015-08-26 / Capes / Neste trabalho estudam-se as propriedades físicas e mecânicas das rochas da Bacia do Rio do Peixe (BRP), provenientes do furo estratigráfico 1-BSB01-PB. Esta bacia, localizada no extremo oeste do estado da Paraíba, tem se tornado alvo de estudos exploratórios, face à ocorrência de óleo próximo a superfície, à NW da cidade de Sousa. Em sua caracterização faciológica, identificam-se cinco fácies sedimentares: calcilutito vermelho, calcilutito cinza, arenito, folhelho negro e marga. Por meio de ensaios de propagação de ondas sísmicas, experimentos de petrofísica básica, e ensaios mecânicos de compressão uniaxial com o martelo de Schmidt, determinam-se para as amostras de rochas da BRP, a porosidade, as densidades total e de grão, as velocidades sísmicas, a resistência mecânica e as constantes elásticas estáticas e dinâmicas, destacando-se o módulo de Young. Os resultados obtidos
mostram que as rochas em estudo apresentam valores de porosidade entre 0,5 e 20%, resistência à compressão uniaxial de 18 a 93 MPa, módulos de Young dinâmicos entre 9 a 58 GPa, desde 1,1 até 6 vezes maiores que os correspondentes módulos estáticos. As correlações observadas para as diferentes propriedades físicas e mecânicas mostram-se fortemente influenciadas por características como presença de material carbonático, matéria orgânica, óleo e estruturas sedimentares e tectônicas, evidenciando a complexidade das rochas analisadas. / In this paper, studies on physical and mechanical properties of rocks from the stratigraphic hole 1-BSB01-PB, in the Rio do Peixe Basin (BRP), are performed. This basin, located in the far west of the state of Paraíba, has become the subject of exploration studies due to the occurrence of oil near the surface, in the NW of Sousa city. In his facies characterization is possible to identify five sedimentary facies: red calcilutite, gray calcilutite, sandstone, black shale and marl. From seismic wave propagation tests, experiments of basic petrophysics, mechanical tests on uniaxial compressive with Schmidt’s hammer, are determined for samples of BRP rocks the porosity, the bulk and grain densities, the seismic velocities, the mechanical strength and the static and dynamic elastic constants, highlighting the Young's modulus. The results obtained show that the studied rocks have porosity values between 0.5 and 20%, uniaxial compressive strength from 18 to 93 MPa, dynamic Young's modulus between 9 and
58 GPa, from 1,1 to 6 times greater than the corresponding static modules Correlations observed for the different physical and mechanical properties shows strongly influences by characteristics such as the presence of carbonate material, organic material, oil and sedimentary and tectonic structure, showing the complexity of the analyzed rocks.
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