Modelagem estratigráfico-sedimentológica da distribuição espacial de fácies sedimentares em reservatório carbonático aptiano da bacia de Santos

• Autor(a) principal: Faria, Desiree Liechoscki de Paula
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/13911
• topic: 3D forward modeling; Aptian carbonates; Lacustrine sag carbonates; Carbonate reservoir; Rifted margin; Modelagem estratigráfico-sedimentológica tridimensional; Carbonatos aptianos; Carbonatos lacustres da fase sag; Reservatório carbonático; Margem rifteada; CNPQ::CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA

A Stratigraphic-sedimentological forward modelling is a valuable technique to test the role of parameters that may act in the depositional process of sedimentary rocks. This method was applied in the Santos basin, Brazil, with the aid of the software DIONISOS, to put forward possible depositionalscenarios for an Aptian section of a lacustrine carbonate platform developed within the sag stage of the basin (uppermost pre-salt section). Different parameters were tested in a variety of simulations aiming at reproducing the carbonate facies spatial distribution and stacking pattern across the platform. Facies distribution was revealed from well data to be composed of four main carbonate facies: laminites, grainstones, stromatolites and spherulitites. The applied modelling parameters were: base level oscillations; variable carbonate depositional rates; and distinct bathymetric intervals for carbonate deposition. A variety of scenarios were simulated but only six of them are explored in this work. Among them, Model 5 proved itself to be the most successful one in terms of reproducing the original carbonate sediment thickness (c.100 m), the occurrence of grainstones and stromatolites as proximal and intermediate facies, respectively; and the stacking pattern as observed in the 10 wells availables for this study. Thus, based on three-dimensional forward stratigraphic-sedimentological modellings, our work reveals that a set of possible environmental conditions capable of explaining the carbonate deposition as seen in well data would be: a slow carbonate depositional rate (0.08mm/y for a 2.4 My in this case), indicative of a larger microbial contribution; and lake level oscillations essentially induced by arid climatic condition. Such results provide new scenarios for the understanding of environmental conditions which may have led to the deposition of the Santos basin carbonate platform focused in this study. They open up, as well, new perspectives for the application of forward stratigraphic-sedimentological modelling for the development of conceptual models for other sag platform settings of the same Aptian carbonates of the Santos basin