The objective of this thesis is to study two Basins of the Gulf of Guinea (GoG), namely the Dahomey and the Liberian Basins. These Basins are located in the northern part of the GoG, where oil and gas exploration has significantly increased in the last 10 years or so. We proposed geological descriptions of these two Basins. The key characteristics of the two models are the presence of channels and pinch-outs for depths of between 1 km and 2 km (these values are rescaled for our numerical purposes to 600- m and 700-m depths) and normal faults below 3 km (for our numerical purposes we use 1 km instead of 3 km). We showed that these models are consistent with the plate tectonics of the region, and the types of rocks and ages of rocks in these areas. Furthermore, we numerically generated seismic data for these two models and depth-migrated them. We then interpreted the migrated images under the assumption that the geologies are unknown. The conclusions of our interpretations are that we can see clearly the fault systems in both models. However, our results suggest that seismic interpretations of the channels and pinch-outs associated with the geology of the Dahomey and Liberian Basins will generally be difficult to identify. In these particular cases, we missed a number of channels and pinch-outs in our interpretations. The limited resolution of seismic images is the key reason for this misinterpretation.

Orientador: Alexandre Campane Vidal / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-12T08:28:49Z (GMT). No. of bitstreams: 1 Lima_LuizMauricioSilvade_M.pdf: 4795138 bytes, checksum: 429f15da9df616f78f3feee5b40ebb38 (MD5) Previous issue date: 2007 / Resumo: A caracterização de reservatórios e de fundamental importância para a implantação de uma estratégia de produção de um campo petrolífero. Os modelos geológicos permitem o entendimento da gênese do reservatório em estudo com a possibilidade de realizar uma distribuição espacial e qualitativa das principais heterogeneidades. Esta analise envolve quantidade enorme de variáveis devido à complexidade do problema gerando um grande numero de cenários prováveis. Para o modelo geológico da área, fundamentada na analise de dez perfis elétricos e radioativos, foi possível a determinação de intercalações de camadas, definição das fácies e a definição da porosidade e permeabilidade dos arenitos. Devido a presença de pacotes mais espessos e contínuos de arenitos na direção SW-NE, portanto com maior razão areia/folhelho, infere-se esta como a direção preferencial de aporte dos sedimentos. A analise geoestatistica foi realizada para as principais variáveis referentes à caracterização de reservatórios. Esta analise definiu a direção SW-NE como a direção preferencial de aporte dos sedimentos e forneceu uma estimativa de volume de óleo in cento. Devido a elevada incerteza na estimativa desse volume, foi realizada a simulação estocástica levando em consideração as variáveis topo e base do reservatório, distribuição de arenitos e porosidade. Os resultados da simulação estocástica demonstram a variação dos volumes de óleo in situ. / Abstract: The reservoir characterization model is of fundamental importance for the planning of a strategy production petroleum field. The geological models allow the understanding of the reservoir's spacial and qualitative distribution of its principal heterogeneity. This analysis involves enormous amount of variables due to the complexity of the problem, which generates a great number of probable scenarios. For the geological model of the area the interpretation is based on the analysis of ten electrical and radioactive logs, with which it is possible to determine the intercalations layers and the definition of the porosity and permeability of the sandstones. The presence of thicker and continuous packages of sandstones in the NE-SW direction, with its high net to gross ratio, is probable due to the existence of a preferential direction of the sediment sources. The geostatistical analysis was carried out for the principle variables regarding the characterization of the reservoir. This analysis defined the direction SW-NE as the preferential direction of the sediments sources and in situ oil volume estimate. Due to the raised uncertainty in the estimate of this volume, a stochastical was carried out with the consideration of; top and base variables of the reservoir, distribution of sandstones and porosity. The results of the stocastical simulations show the variation of the volume in situ of oil. / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo