--> Multiscale Characterization of Coquinas Reservoirs in Analogues Outcrops, Sergipe Alagoas (Brazil) and Lusitanian (Portugal) Basins

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Multiscale Characterization of Coquinas Reservoirs in Analogues Outcrops, Sergipe Alagoas (Brazil) and Lusitanian (Portugal) Basins

Abstract

The coquinas reservoirs have been widely studied because they constitute important intervals in oil production with accumulation model controlled by stratigraphic, structural and diagenetic factors in complex carbonates systems. The objective of this study was to develop a robust analysis of multi-scale properties related to the permo-porous system in analogues outcrops of coquina reservoirs, attempting to the comprehension of associated diagenetic processes evolution. This approach aims for the integration of different tools in 3D modeling and permo-porous reservoir characterization, which in this study focus on outcrops of two coastal basins with coquinas intervals, the Sergipe-Alagoas and Lusitanian Basins. The methodology applied in deposits of Morro do Chaves (Intercement Quarry, Alagoas State, Brazil) and Corálico do Amaral formations, in the Lusitanian Basin (outcrop in Salgado Beach, São Martinho do Porto, Portugal), included the description and systematic sampling of lithotypes, Gamma Ray logging, 3D digital imaging (Laser Scanner-Lidar), petrographic characterization, petrophysical analysis of samples, and biostratigraphic and paleoenvironmental context of related geological models. The integrated analysis of these attributes were supported by the high-resolution sequence stratigraphyc principles. In Intercement Quarry, were described 12 depositional cycles characterized into 5 facies (Calcirrudite, Calcarenite, Calcilutite, Shale, Sandstone), in which little thick shales, but with large lateral continuity, were used as markers surfaces between the coquinas for 3D modeling. These conclusions were based on compositional and geometrical characteristics obtained from 6 geological logs described, and depositional architecture described and captured in the field by Laser Scanner. The 3D geological models were generated in the RMS software, and made possible the representation of compositional heterogeneities responsible for the permo-porous properties heterogeneities distribution, conditioned to diagenetic aspects and fluid flow control. Data acquisition in formation Corálico do Amaral is in progress and by the end of these studies will serve as a comparison of analogues Pre-salt models.