Campo de Anambé - Bacia de Sergipe-Alagoas : um estudo de mapeamento dos ambientes deposicionais acerca de um reservatório principal do bloco leste

Abstract

The Coqueiro Seco Formation, consists of sandstones and shales deposited in a fluvial-deltaic environment of the rift phase of the Sergipe-Alagoas Basin, containing high exploratory interest due to its reservoirs presenting good permoporous characteristics, with the presence also of generating and capping shales, in Campo de Anambé (Alagoas Sub-basin). Stratigraphic analyzes are important for the recognition of formations/zones used in the zoning of sedimentary deposits. The main contribution of this work was to approach in a connected way the stratigraphy of sequences with the evaluation of formation and electrofacies, for the construction of maps of depositional environments, a highly recommended approach, but which is not always applied. The stratigraphic study in the wells allowed the identification of the formations in their determined hierarchical orders and the individualization of sedimentary packages through the recognition of tectonic cycles of the rift phase. As a result, it was possible to correlate the producing zone "A" with the aspects that present their profiles, as well as, curves of clay volume, total and effective porosities were estimated, in addition to the water saturation curve indicating a zone saturated in gas, with variable net pay between 5.25 and 15.8 meters. From the perspective of the study of electrofacies, three groups of distinct facies were obtained: shales, clayey sandstones and sandstones. Density diagrams, neutrons and gamma rays were responsible for closing the understanding. Therefore, it was possible to compile electrofacies and maps to develop a depositional environment map for Zone “A” showed a possible interpretation of channel filling and meanders.