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Resumo As curvas de proporção possuem um importante papel na caracterização geológica de depósitos de hidrocarbonetos. Por meio delas é possível definir, para deteminados intervalos, os tipos de íácies dominantes, e essas infomações podem posteriomente auxiliar na modelagem do reservatório sendo usadas como dados condicionantes e entendimento de tendências. Porém, ao serem construídas via média aritmética essas curvas não carregam consigo a influência dos poços e a localização dos mesmos. Considerando essas infomações, pode-se gerar curvas mais adaptadas a realidade e com informações assim, mais confiáveis. Desse modo, o principal objetivo deste trabalho é mostrar uma metodologia de construção das curvas de proporção utilizando a krigagem da média para estimar as proporções. A vantagem dessa técnica é que a localização dos poços e a possível área de influência dos mesmos pode ser considerada. Com isso, pode-se mostrar como gerar de maneira mais eficiente as curvas de proporções, que uma vez construídas podem auxiliar na caracterização de reservatórios, principalmente no que diz respeito à modelagem litológica. Pcz/crvrczs-CÃc7vc: Curvas de proporção, krigagem da média, caracterização de reservatórios, fácies. Abstract Krz.gz.77g o/propor/z.o#s a4sz.7eg /7?ecr7? hz.gz.#g.The proportion curves have an important role in petro-1eum geology. With this tool it is possible to define specific intervals for the dominant facies and, as result we can use the proportion curve as a trend in lithological modeling. However, when the proportion curves are generated they don't consider the well influence and the location ofthe wells. When we consider those information is possible to generate a more effective proportions curves. So, the main aim of this paper is to present a new technique to generate the proportion curves based in the mean kriging. The main advantage of this methodology is that the well location and his influence zone are considered in the process. This methodology indicated a efficient way to generate the proportion curves that can be used to support in a decisive way the reservoir characterization process linking to the lithological modeling.

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Hydrocarbon discoveries in regions such as the Brazilian Equatorial Margin, Equatorial Africa and French Guiana have recently confirmed their importance as new exploration frontiers. The Mundaú sub-basin, located on the Brazilian Equatorial Margin, is an oil and gas producing region with four producing fields in shallow water: Xaréu, Atum, Espada e Curimã. In order to understand the structural and seismic-stratigraphic frameworks of an oilproducing area of the Brazilian Equatorial Margin, this work addresses the 3D geometry and 2 spatial distribution of main faults in the Curimã and Espada fields. The occurrence of hydrocarbons in the Mundaú sub-basin is compared with fields in other parts of the Brazilian Equatorial Basin, and in Equatorial Africa. Data from wells and a 3D post-stack timemigrated multichannel seismic volume are used to define nine (9) main seismic-stratigraphic units: the syn-rift Mundaú Formation (Units 1, 2, 3 and 4); the transitional Paracuru Formation (Unit 5) and the drift Ubarana (Uruburetama and Itapagé Members, Units 6 and 7), Tibau and Guamaré Formations (Units 8 and 9). The study area is dominated by NW-SE planar normal faults, basinward-dipping, that formed multiple half-grabens and tilted blocks with small anticlines and synclines genetically related to a transtensional system. Three types of plays are recognised in the Mundaú sub-basins: structural, combined (structural-stratigraphic) and stratigraphic (turbiditic). In the eastern part of the region where the basement is shallow, no oil was found. Conversely, oil was discovered in an anticlinal trap formed on a hanging-wall block analogous to fields in Côte D'Ivoire-Ghana transform margin. This work shows that combined traps on footwall blocks are successful plays near the shelf break of the Mundaú sub-basin, in similarity with the Espoir and Baobab fields in Ivory Coast Basin. Furthermore, turbiditic reservoirs in drift units are analogous to the Stabroek block in Guyana and prospects in the Gulf of Guinea. The structural and petroleum-play analyses in this work are therefore crucial to understand the multiple geological processes leading to the trapping of hydrocarbons in the larger Equatorial Atlantic Ocean.