| Autor: |
Barberes, Gabriel A., Marques, Flávia C., Almeida, Dalva A. L., Peixoto, Linus Pauling F., Maia, Lenize F., Sant'Ana, Antonio Carlos, Andrade, Gustavo F. S., Izumi, Celly M. S., Salgado-Campos, Victor, Feital, Thiago, de Oliveira, Luiz Fernando C., Albuquerque, Ana Luiza |
| Předmět: |
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| Zdroj: |
Geosciences (2076-3263); Nov2024, Vol. 14 Issue 11, p286, 22p |
| Abstrakt: |
The Coqueiros Formation, a strategic stratigraphic unit within the Lagoa Feia Group (LFG) in the Campos Basin offshore Brazil, is known for its lacustrine carbonate deposits, which include both organic-rich shales and economically important "coquina" reservoirs. While coquina facies are widely recognized as reservoirs, the source-rock potential of the intercalated shales remains relatively underexplored. This study aims to characterize the mineralogy and thermal maturity of the Coqueiros Formation to assess its potential as a source rock, using a multi-technique approach integrating X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Raman spectroscopy analyses of shale samples from two wells: 3-BP-11-RJS and 6-DEV-18P-RJS. XRD analyses revealed a heterogeneous mineralogy dominated by carbonates (calcite and dolomite) and quartz, with significant contributions from clay minerals and trace minerals such as pyrite and barite. SEM imaging revealed a heterogeneous fabric with grain size, morphology, and porosity variations, reflecting a dynamic lacustrine depositional setting influenced by storm events and fluctuations in terrigenous input. The presence of authigenic minerals, as reported in other studies, such as saddle dolomite, mega-quartz, and various sulfides, provides evidence for hydrothermal alteration, likely related to Late Cretaceous magmatic activity in the Campos Basin. Raman spectroscopy yielded equivalent vitrinite reflectance (Ro%) values consistently exceeding 1.00, ranging from 1.03 to 1.40, indicating that the organic matter in the Coqueiros Formation shales has attained a high thermal maturity level, surpassing the oil window and reaching the condensate wet gas zone. The mineralogical and equivalent maturation data presented herein provide a valuable foundation for future studies, highlighting the complexity and heterogeneity of the Coqueiros Formation and its potential significance as a source rock within the Campos Basin petroleum system. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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