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Seabed environmental monitoring programmes have been conducted at oil installations in the North Sea for many years. Such studies seek to determine the areal extent of the spread of contaminated cuttings and effects on assemblages of benthic organisms. Survey programmes usually follow a prescriptive programme with respect to the numbers of samples, mesh size and level of taxonomic identification. This thesis examines the effects of altering these survey components on the information content of three commonly used ordination methods, PCA, DCA and CA, with the aim of determining the minimum necessary expenditure to show the same outputs. The use of microbial bioassays was investigated as a potential alternative means of assessing the extent of infaunal disturbance. <I>Minimum number of replicates</I>. When analysing data from a strong environmental gradient, one replicate sample per station provided the same visual information as the total data set of two replicates. The DCA and CA procedures provided outputs which were easily interpretable ecologically, but the PCA biplots were difficult to interpret. Analysis of data from a weak environmental gradient required a higher number of replicates for each technique and outputs were more variable at low replicate numbers. <I>Taxonomic resolution</I>. When infauna were aggregated to the taxonomic level of class, the information content of the three ordination methods was the same as recorded for species level. However, at the taxonomic levels of order and phylum the information on the bi-plots was difficult to interpret. Although this suggests that there exists the potential for reducing the cost of analysis, further corroboration with different data sets would be required. <I>Sieve size</I>. Primary screening of 0.5 mm mesh fauna by a 1.0 mm mesh may be a more cost effective strategy than either a 1.0 mm or 0.5 mm fraction although there was some loss of information on the ordination bi-plots.

Submitted by thiago martins silveira (t.silveira2003@ig.com.br) on 2015-12-11T19:37:29Z No. of bitstreams: 1 Dissertação THIAGO envio vitor 11.12.pdf: 1008243 bytes, checksum: 0a7a2e57fa290ee5228d81e283f0d348 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2015-12-21T18:14:36Z (GMT) No. of bitstreams: 1 Dissertação THIAGO envio vitor 11.12.pdf: 1008243 bytes, checksum: 0a7a2e57fa290ee5228d81e283f0d348 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2015-12-21T18:14:53Z (GMT) No. of bitstreams: 1 Dissertação THIAGO envio vitor 11.12.pdf: 1008243 bytes, checksum: 0a7a2e57fa290ee5228d81e283f0d348 (MD5) / Made available in DSpace on 2015-12-21T18:15:06Z (GMT). No. of bitstreams: 1 Dissertação THIAGO envio vitor 11.12.pdf: 1008243 bytes, checksum: 0a7a2e57fa290ee5228d81e283f0d348 (MD5) Previous issue date: 205-05-28 / O objetivo deste trabalho é propor a utilização do arcabouço teórico das opções reais e a posterior aplicação do modelo binomial na avaliação de projetos relacionados à exploração e produção de petróleo, tendo em vista a flexibilidade gerencial, os riscos e as incertezas técnicas e de mercado que norteiam o setor petrolífero upstream. Ademais, a aplicação do modelo proposto capta o papel crucial da volatilidade do preço do petróleo na avaliação da decisão de investimento e revela a existência dos custos irrecuperáveis extremos decorrentes do ativo real, neste caso, a unidade marítima de petróleo. Assim, com o intuito de prolongar o ciclo de produção de unidade marítima de petróleo com características preestabelecidas, propõe-se a avaliação econômica de duas alternativas tecnológicas para a extensão de vida útil da plataforma marítima objeto de estudo, sendo estas alternativas tratadas como opções de expansão. As alternativas propostas são duas: o afretamento da UMS (Unidade de Manutenção e Segurança) acoplada à plataforma e a docagem da plataforma a partir da desmobilização, isto é, o descomissionamento, e envio da plataforma ao estaleiro. Na aplicação da primeira opção, a UMS se configura em uma embarcação equipada com toda a estrutura necessária para a realização de serviço de manutenção e revitalização, sem que ocorra interrupção da produção de petróleo. Por outro lado, a opção de descomissionamento é desprovida de receita até o retorno da plataforma do estaleiro. No que tange à metodologia do presente trabalho, o modelo binomial com probabilidades de risco neutro é aplicado considerando a receita proveniente da produção de petróleo de uma plataforma marítima com sistema de produção flutuante com 14 poços, sendo 10 produtores e 4 injetores e sustentada por 8 linhas de ancoragem. Também é definida a volatilidade do projeto como sendo a volatilidade do preço do petróleo. Por fim, as opções de expansão podem ser exercidas a qualquer momento antes da data de expiração das opções, data esta coincidente para ambas as opções e referente ao término de contrato de afretamento da UMS, que corresponde ao período de cinco anos. Neste período de cinco anos, as duas alternativas são exercidas a partir do primeiro ano, com receitas e custos distintos em virtude das especificidades decorrentes das alternativas tecnológicas propostas. A partir da aplicação do modelo binomial com probabilidades de risco neutro sob o enfoque das opções reais, as duas alternativas tecnológicas são tratadas como opções americanas na avaliação econômica da revitalização e manutenção da plataforma marítima. Também realiza-se a análise tradicional do VPL para as duas alternativas. As duas análises apontam para a escolha da UMS como alternativa ótima de expansão da vida útil da plataforma. Ademais, a análise sob o enfoque das opções reais capta um valor adicional em ambas as alternativas tecnológicas, fruto das características inerentes à indústria petrolífera. Quanto à estrutura do trabalho em questão se divide em cinco capítulos: introdução, referencial teórico, metodologia, apresentação dos resultados e as considerações finais. / This paper purposes the use of theoretical framework of real options and posterior employment of binomial model in project evaluation concerning the exploration and production of oil, in view of manager flexibility, risks, techniques and market uncertainties that guide the upstream oil sector. Furthermore, the apliccation of the proposed model captures the crucial role of the volatility of oil price in the evaluation of investment decision and brings out the presence of high sunk costs resulting from real asset, in this case, offshore oil platform. Thus, in order to prolong the maritime unit of production cycle oil with predetermined characteristics, it is proposed economic evaluation of two alternative technologies for the lifetime extension of offshore studied, and these alternatives treated as options to expansion. The alternatives proposals are: the chartering of MSU (Maintenance and Safety Unit) coupled to platform and the send of offshore platform in the dock after its decommissioning and its send to shipyard. In the implementation of the first option, MSU configures a equipped vessel with all the necessary structure to perform maintenance and revitalization without interruption of oil production. On the other hand, the option of decommissioning is devoid of revenue until the regress of the offshore platform from the shipyard. Concerning the methodology of this study, the binomial model with risk-neutral probabilities is applied regarding the revenue arising from the oil production of offshore platform with floating production system that accept 14 oil wells, including 10 production well and 4 injection well and supported by 8 anchor line. The volatility of project is also defined as the volatility of oil price. Lastly, the options to expand may be exercised anytime before its expiration date that coincides for both options and concerning the end of contract of MSU that correspond to the period of five years. In this period, both alternatives are exercised from the first year, with differents revenue and costs by virtue of specificities resulting from the technological alternatives proposals. From the application of binomial model with risk-neutral probabilities from the standpoint of real options, these two alternatives are treated as american options in the evaluation of revitalization and maintenance of offshore platform. Also takes place the traditional analysis of NPV for both alternatives. These two analysis point at choice of MSU as the best alternative for prolonging the useful life of offshore platform. Moreover, the analysis from the standpoint of real options capture additional value in both technological alternatives, the result of characteristics inherent in the oil industry. As for the structure of the work in question is divided into five chapters: introduction, theoretical framework, methodology, presentation of results and final considerations.