Orientadores: Martin Tygel, Eduardo Filpo Ferreira da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-25T22:08:42Z (GMT). No. of bitstreams: 1 Cardoso_ClaudioGuerra_M.pdf: 5757657 bytes, checksum: 5b4ea3b5608c625fce78a747dffdf8e0 (MD5) Previous issue date: 1999 / Resumo: Atualmente, cerca de 90% das reservas brasileiras de óleo localizam-se nas porções submersas das bacias sedimentares costeiras. Nessas bacias, a sísmica de reflexão é uma das principais ferramentas de que dispõe o profissional de exploração e de desenvolvimento de campos de petróleo. Como a interpretação dos dados sísmicos considera somente as reflexões primárias, é necessário que estes estejam livres de ruídos, particularmente, da reflexão múltipla do fundo do mar, que é o ruído mais danoso em dados marítimos. A presente dissertação descreve um método novo de eliminação de múltipla do fundo do mar de 1ª ordem em configuração de afastamento fonte - receptor comum, por empilhamento Kirchhoff, mostrando exemplos numéricos de aplicação do mesmo em dados sintéticos. Num desses exemplos, no qual concorrem a múltipla e uma reflexão primária - que poderia advir de um refletor de interesse - após a eliminação da múltipla, as diferenças nas amplitudes da primária, quando comparadas com as amplitudes sem a interferência da múltipla, não ultrapassam 5%. Dessa forma, o método, por preservar as amplitudes das primárias após a eliminação da múltipla, se configura como muito adequado à geofísica de reservatórios / Abstract: At present, about 90% of Brazilian oil reserves are located in offshore sedimentary basins. In these basins, reflection seismic is one of the most important tools in exploration and field development. As seismic data interpretation only deals with primary reflections, is important to have noise-free, amplitude preserved primaries. The most harmful noise in marine data is the first-order, sea-bottom multiple reflection. This dissertation describes a new method for first order, sea-bottom, multiple elimination by means of a Kirchhoff - type stacking, in common offset configuration, showing its application to synthetic seismic data. In one of the examples, in which the multiple and a primary reflection interfere, the differences between amplitudes of primary reflection after application of the method and primary computed with no such interference are smaller than 5%. Due to the primaries amplitude-preserving property, this method provides a very reliable image to reservoir geophysics, such as amplitude versus offset analysis (AVO) and seismic attribute determination / Mestrado / Mestre em Engenharia de Petróleo

A multiple-sensor optical shape measurement system (SMS) based on the principle of white-light fringe projection has been developed and commercialised by Loughborough University and Phase Vision Ltd for over 10 years. The use of the temporal phase unwrapping technique allows precise and dense shape measurements of complex surfaces; and the photogrammetry-based calibration technique offers the ability to calibrate multiple sensors simultaneously in order to achieve 360° measurement coverage. Nevertheless, to enhance the applicability of the SMS in industrial environments, further developments are needed (i) to improve the calibration speed for quicker deployment, (ii) to broaden the application range from shape measurement to deformation field measurement, and (iii) to tackle practically-challenging surfaces of which specular components may disrupt the acquired data and result in spurious measurements. The calibration process typically requires manual positioning of an artefact (i.e., reference object) at many locations within the view of the sensors. This is not only timeconsuming but also complicated for an operator with average knowledge of metrology. This thesis introduces an automated artefact positioning system which enables automatic and optimised distribution of the artefacts, automatic prediction of their whereabouts to increase the artefact detection speed and robustness, and thereby greater overall calibration performance. This thesis also describes a novel technique that integrates the digital image correlation (DIC) technique into the present fringe projection SMS for the purpose of simultaneous shape and deformation field measurement. This combined technique offers three key advantages: (a) the ability to deal with geometrical discontinuities which are commonly present on mechanical surfaces and currently challenging to most deformation measurement methods, (b) the ability to measure 3D displacement fields with a basic single-camera single-projector SMS with no additional hardware components, and (c) the simple implementation on a multiple-sensor hardware platform to achieve complete coverage of large-scale and complex samples, with the resulting displacement fields automatically lying in a single global coordinate system. A displacement measurement accuracy of ≃ 1/12,000 of the measurement volume, which is comparable to that of an industry-standard DIC system, has been achieved. The applications of this novel technique to several structural tests of aircraft wing panels on-site at the research centre of Airbus UK in Filton are also presented. Mechanical components with shiny surface finish and complex geometry may introduce another challenge to present fringe projection techniques. In certain circumstances, multiple reflections of the projected fringes on an object surface may cause ambiguity in the phase estimation process and result in incorrect coordinate measurements. This thesis presents a new technique which adopts a Fourier domain ranging (FDR) method to correctly identifying multiple phase signals and enables unambiguous triangulation for a measured coordinate. Experiments of the new FDR technique on various types of surfaces have shown promising results as compared to the traditional phase unwrapping techniques.