124 resultados para Piezocone de resistividade


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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A pesquisa teve como objetivos gerais à aplicação dos métodos geoelétricos na hidrogeologia, visando: (1) estudos para captação de águas subterrâneas para abastecimento em geral; e, (2) estudos das contaminações de solos, rochas e águas subterrâneas, envolvendo as fases de investigação preventiva, confirmatória, remediação e monitoramento. Como objetivos específicos, através da aplicação dos métodos da eletrorresistividade e polarização induzida, utilizando-se das técnicas de campo da sondagem elétrica vertical - arranjo Schlumberger e caminhamento elétrico - arranjo dipolo-dipolo, e dos parâmetros de Dar Zarrouk, tem-se uma discussão e proposição metodológica e prática, em função da geologia local, sobre os produtos obtidos por essa metodologia, tais como: caracterização geológica na identificação de aqüíferos promissores e investigação de áreas contaminadas e/ou sujeitas à contaminação. Portanto, esse trabalho procurou apresentar uma discussão sobre os principais métodos e técnicas de campo dos métodos geoelétricos aplicados em estudos hidrogeológicos, com destaque na captação para abastecimento e diagnóstico de solos, rochas e águas subterrâneas frente a poluentes. A proposição metodológica apresentada, procurou aplicar uma relação entre a resolução de métodos e técnicas com custos e prazos adequados a um trabalho envolvendo a Geofísica Aplicada em estudos hidrogeológicos. O emprego da eletrorresistividade, com as técnicas da SEV e CE, por si só, revela-se decisivo para atingir os mais variados fins envolvendo esses tipos de estudos. A resistividade elétrica dos materiais geológicos, é definida, principalmente, em função de seus constituintes mineralógicos e o tipo de fluido presente, sendo, portanto, ideal para os estudos hidrogeológicos de maneira geral. Cabe ressaltar ainda... (Resumo completo, clicar acesso eletrônico abaixo)

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The main goal in this research is a tectono-estructural characterization of the Cherne, Albacora and Namorado Fields, located at Campos Basin, in order to investigate the relationship between the geologic evolution and the rock´s physical properties of the reservoir, and how they affect the hydrocarbon accumulation in those fields. Well correlations show that the inferior turbidites have a regional lateral continuity. Basic petrophysics analysis, calculated here, shows that the three fields present porosity values that range from 15 to 20%, shale volume range from 26 to 30% and formation water saturation range from 23 to 45%, based on formation water resistivity dada from Albacora Field. Petrophysics maps feature a trend in Albacora Field that increase the porosity values to SE, and in Cherne and Namorado Field the trend increase towards N. Seismic horizons where interpreted between the first appearance of the Namorado Sandstone and the top of Quissamã Formation. This interval presents normal listric faulting, in Cherne and Namorado Field with NWSE and NE-SW direction, and sedimentation trend to NW-SE, in Albacora Field the faulting presents a NNE-SSW and N-S direction, with a sedimentation trend to NE-SW. Seismic attribute maps present amplitude anomalies close to the producing wells, and on Namorado Field, it indicates a potential hydrocarbon accumulation in the NE region. For each field is indicated laboratory tests for a better characterization of the petrophysical properties, since that they don’t form the same reservoir level, therefore, not influencing the water saturation calculation

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The mining research is a complex activity, which should preferably involve the combination of direct and indirect techniques of geological research. The increasing demand for base metals in domestic and international markets provide the revaluation of mineral occurrences, which can be converted into deposits and mines. This paper presents the results of the application of geophysical methods of electric resistivity and induced polarization in main foliation parallel to the arrangement of the area, in a deposit of oxides and hydroxides in massive and disseminated ores, docked in gneisses and quartzites, located in the municipality of Itapira, in the North of the State of São Paulo in Brazil. Inversion models indicate the predominance of high cargabilidade that partially coincide with low resistivity values. Integration of geophysical data made possible the drafting of sections of electric walking with cross-checking distance x depth, for detailing your target. The integrated analysis of geophysical and geological structural data leads to the conclusion that the primary mining suffers structural control with the regional foliation in ores

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Neste trabalho, apresenta-se o desenvolvimento de um sensor de gás amônia sobre substrato de papel, impresso por jato de tinta térmico. Para a realização do trabalho formulou-se uma “tinta”4 de polianilina (PANI), adequada para uso na impressora térmica. Neste tipo de impressão, é necessário que a tinta de PANI seja preparada de forma que a maior parte do seu volume seja de água. A PANI, em seu estado desdopado, foi dissolvida em n-metil-2-pirrrilidona (NMP), e com a adição de água em determinadas condições de preparo e proporção, foi possível formar uma tinta de PANI/NMP/H2O estável e adequada para o uso na impressora térmica, podendo-se assim depositar filmes de PANI sobre substratos flexíveis, como por exemplo, diversos tipos de papéis. Neste trabalho, tintas de PANI foram depositadas sobre papel comum (sulfite) e papel fotográfico (glossy). A caracterização morfológica, por microscopia ótica, indicou que a qualidade dos filmes foi satisfatória em termos de uniformidade e homogeneidade. A resistividade de superfície dos filmes de PANI, sobre substratos de papel sulfite e fotográfico, é da ordem de 1x109 / , quando desdopado, e 1x104 / , quando dopado com vapor de ácido clorídrico (HCl). As caracterizações elétricas AC sugerem que os filmes de PANI desdopados, sobre ambos os substratos, se comportam similarmente a um circuito equivalente RC, formado por um resistor e um capacitor em paralelo. Entretanto, após a dopagem tal representação deixa de ser válida. Medidas elétricas...(Resumo completo, clicar acesso eletrônico abaixo)

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The issue of solid waste disposal and urban growth are conflictive, since the areas where old uncontrolled refuse disposal were away from the city today are incorporated to the urban area population. Thus, now population is closer to the degradation of contaminants coming from waste disposal, and, in some cases, these areas become housing subdivisions. This work aims to support the diagnosis of a former landfill in the municipality of Rio Claro (SP), using geophysical methods through resistivity anomalies. In order to develop the diagnostic, it was utilized water and soil analysis of a preliminary report and techniques of vertical electrical sounding and electrical profiling. The areas influenced by the garbage presented less resistivity than the one of the natural subsoil. Through the interpretation of results, the local potentiometric map was elaborated, as well as a map of calculated resistivity. The interpretation of these products indicated a disagreement between the groundwater flow and the current topography, leading to an identification of a preferential direction of the contamination plume in the NE-SW. These observations prove the applicability of geoelectrical methods in areas of former waste disposal with little information.

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The geophysical methods are widely applied in environmental characterization and monitoring studies. The resistivity method, in particular, has a wide area of applications, being effective in studies of solid waste landfills. The present work propose a geophysical monitoring in the Cordeirópolis city controlled landfill and analyze relationships between variation of electrical resistivity parameter, the residence time of the solid waste in landfill, the rainfall in the region and the organic matter biodegradation processes. The study has no monitoring system to control the products generated in the organic matter decomposition found in waste such as sealing blanket or leachate or gas drains. The results shows that the electrical resistivity parameter was effective in monitoring the landfill contamination plume

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The study area is the Garoupa Field, located 75 km from the coast of Rio de Janeiro in bathymetric elevation of 125 m and it is the first important offshore discovery of the Campos Basin with hydrocarbon production in the Albian carbonates. The high significance of carbonate rock reservoirs for the global oil industry and its degree of complexity, combined with the fact that the Garoupa Field is a mature field, make this research project interesting to develop a re-exploratory vision of the study area. The objective of this paper is to characterize the physical properties of the Macae Group reservoirs in the Garoupa Field through well correlation techniques, petrophysical analysis and seismic interpretation (3D), in order to evaluate qualitatively and quantitatively the response of geophysical data to the presence of carbonate rock reservoirs. From the analysis of well profiles (gamma ray, resistivity, density and sonic) it was possible to identify six reservoir levels in the Quissamã Formation. As a result, the reservoirs have good correlation between the wells in the Garoupa Field and show lateral facies variation. In the seismic interpretation, structural contour maps were generated in time (ms) from the top of the Macae Group and two horizons that correspond to the reservoir levels. These maps show that the oil producing area of this field is a structural high located at the west of the interpreted seismic cube, and it was classified as a rollover limited by lateral faults forming a horst. The seismic attribute maps show a good response to the reservoirs of the Garoupa Field because they are associated with amplitude anomalies, verified by the correlation between the physical properties of the reservoir rock and seismic data through cross plots, with emphasis in a linear correlation between the resistivity profile and the values of Maximum Absolute Amplitude and RMS Amplitude attributes

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The geophysical methods are used as tools that, together with other data, assist in target detail and sizing of ore bodies. This paper presents the results of the application of DC resistivity geophysical method on a manganese mineral occurrence located in Itapira, in the northern portion of São Paulo state, hosted predominantly in schists and quartzits of Itapira Group. The integration of geophysical data resulted in the elaboration of electrical resistivity models, where it was possible observe that the mineralized body, composed predominantly of manganese oxides and hydroxides, has a pattern of high resistivity (above 5000 Ω.m) both surface and subsurface. The contrast with the host rock is characterized mainly by different minerals assemblages and by the presence of local groundwater. The results accomplished in this paper reveal that the application of DC resistivity method is valid in primary evaluations of supergene deposits

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Geophysics studies in areas impacted by petroleum derivatives describe abnormalities of both low and high electrical resistivity (the opposite of electrical conductivity), confirmed as contaminant phase by chemical analysis: this contradiction can be explained by degrading processes that naturally occur and create sub products that can change the environment conductivity. Monitoring the variation of the parameters mentioned serves as a comparative basis to the variation in geoelectrical parameters, which identified the correlation between the same contaminant parameters and the difference between their behavior studied apart, as well as its relations with the biodegradation process. The results are applied to the fuel distribution and storage sectors, leading to the diagnosis and monitoring of possible groundwater contamination scenarios, and the knowledge of the area exposure time to the contaminant, besides the better remediation alternative and impacts control. Among some conclusions, the most significant are the decrease in conductivity over time, so as the increase in Eh value in the gasoline contaminated tank, as well as the decrease in the pH value in the second tank with ethanol, which can be attributed to its degradation. Comparing the variations in both tanks, it is evident that Eh, pH and electrical conductivity do not behave temporally in a similar way, although some correlations between Eh and pH can be related.

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Pós-graduação em Química - IQ