Dissertações em Geofísica (Mestrado) - CPGF/IG
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/4993
O Mestrado Acadêmico pertente a o Programa de Pós-Graduação em Geofísica (CPGF) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA).
Navegar
Navegando Dissertações em Geofísica (Mestrado) - CPGF/IG por Linha de Pesquisa "EXPLORAÇÃO COM MÉTODOS ELÉTRICOS E ELETROMAGNÉTICOS"
Agora exibindo 1 - 3 de 3
- Resultados por página
- Opções de Ordenação
Item Acesso aberto (Open Access) Estudo hidrogeológico através de perfis geofísicos de poços e sondagens elétricas verticais (SEV's) – Salinópolis-Pa(Universidade Federal do Pará, 2014-02-27) FREIMANN, Boris Chaves; ALVES, José Geraldo das Virgens; http://lattes.cnpq.br/8082136954133058; SILVA, Marcos Welby Correa; http://lattes.cnpq.br/3213216758254128It was realized a correlation of geophysical well logs from the Sanitation Company of Pará (COSANPA) drilled in the city of Salinópolis for the local supply. The study was conducted in many areas of impound, covering 15 wells. The parameters used in the correlation were Self Potential (SP), Electrical Resistivity (ER) and Gamma Ray (GR). Also, for control purposes, was used the lithological log of the wells obtained from samples of drill cutting. This correlation was conducted to evaluate the lateral continuity of permeable and impermeable layers, in order to develop sections of the subsurface with high accuracy. I was also used Vertical Eletrical Sounding (VES) for comparation efect. It was found the probable existence of two major aquifers that lie 60 meters below sea level and have lateral continuity along the full extent of the studied area. It was also found that the top of the basement in the studied area is around 120 meters below sea level. These findings are extremely important for a better location and constructive evaluation for supply wells in the future projects in the city of Salinópolis-Pa.Item Acesso aberto (Open Access) Investigação geofísica forense e antropológica com o método GPR no cemitério do Tapanã e no cemitério perdido de Mosqueiro (Belém, Pará)(Universidade Federal do Pará, 2013-03-22) BRASIL, Diogenes Leão; SILVA, Lúcia Maria da Costa e; http://lattes.cnpq.br/8612431024609774This work was accomplished with ground penetrating radar (GPR), a geophysical method used to investigate the shallow subsurface with high resolution in a non-destructive and noninvasive way. The survey was conducted in two locations in the metropolitan region of Belém, Pará State (Brazil), with 200 and 400 MHz antennas, both in the Tapanã cemetery: the first located in the test site for Controlled Testing of Forensic Geophysics, Environmental and Rescue (FORAMB) and the second one, in a burial zone with concrete cover. Surveys were also conducted in the northwest portion of Mosqueiro Island, across Marajó Bay, with a 400 MHz antenna, where reports of traces of a non-registered cemetery that would have been abandoned for about 80 years and could have been the final destination of cabanos, slaves and indians.These reports led researchers from the Federal University of Pará (UFPA) to visit the site in 1986 to test the veracity of the reports. At FORAMB the monitoring of the three targets that were buried there in 2007 was continued: a human body in a shallow grave 0.8 m deep, a tunnel simulated by a hollow wooden box placed 1 m deep and a box with metal, simulating weapons, deposited at 0.8 m depth. In the burial zone with concrete cover, the survey efforts focused on the effect of the concrete cover.The results obtained in the Tapanã cemetery show the usefulness of GPR in viewing targets under shallow soil cover and saturated clay, typical of the Amazon region, even when it is covered by a layer of concrete. These results reinforce the importance of pooling 2D and 3D data for interpretation of results; the GPR profiles over the concrete covering the bodies in various ages of burial, moreover, show significant variations of the responses, partly observed in other studies. The Mosqueiro results showed that ancient targets in climatic and geological conditions of the Amazon region, do not allow easy detection. It is possible that the remains of the decomposed bodies are not amenable to detection, but the discontinuity of the strata above the burial due to excavation, and the resulting concavity of the collapsed grave infill material may be diagnostic.Item Acesso aberto (Open Access) Tomografia eletromagnética poço-a-poço usando os reguladores de suavidade global e de variação total(Universidade Federal do Pará, 2014-07-07) SANTANA, Julielson Monteiro de; SOUZA, Victor Cezar Tocantins de; http://lattes.cnpq.br/6394094668539482In this work, we describe the forward and inverse problems of Crosswell electromagnetic tomography. The model geometry has azimuthal symmetry, which significantly simplifies both the forward modeling and the inversion processing, reducing a 3-D tensor equation to a scalar two-dimensional form. In the forward problem we use the finite element method for the numerical solution of the Helmholtz equation. In the inverse problem, we discuss the use of three stabilizing functionals: Global smoothness (GS), Total Variation (TV), and Absolute Equality (AI). The first one uses a smoothing function on L2 norm, while the second uses smoothing on the L1 norm, which accepts abrupt changes between adjacent parameters. Our results show that the use the TV method generated good estimates of the geometry and conductivity of bodies, both for small and for large conductivity contrasts between the targets and the surrounding environment. We also note that the Total Variation regularization showed a better estimate of the parameters, compared to Global Smoothness. In most of the synthetic models used in this work, we obtained a better estimate of the bodies when we used Absolute Equality constraints to the cells at the edges of the inversion grid, in addition to the stabilizing functionals.