Serra Geral Formation (Cretaceous, Paraná Basin) – an analogous for igneous-basic reservoirs of the Brazilian Continental Margin

Abstract

The study of igneous rocks is of special interest in sedimentary basins with hydrocarbon production due to the possibility of being unconventional volcanic reservoirs. The fields of Badejo and Linguado of the Campos Basin, located in the southeastern continental margin, produce hydrocarbons from fractured volcanic reservoirs that represent their economic basement. They comprise flows of fractured basic rocks, vesicles and intercalations of arenaceousintertraps. These production fields are offshore and the unconventional reservoir is submerged at great depths, making difficult to understand both the model and the permo-porous system. Thus, it is necessary to provide an analogous model in subsurface in order to allow the visualization and the understanding of the reservoir and the permoporous features. The Serra Geral Formation (volcanism recorded in the Cretaceous of the Paraná Basin) is considered an analogous model to fractured volcanic reservoir. Taking this into account, we propose herein an analogous modelbased on the study of volcanicsoutcroups of this formation, located in the Salto do Jacui and Torres regions, Rio Grande do Sul State, allied to the use of petrographic and geochemistry techniques, X-ray diffractometry and scanning electron microscopy. In the present model, faults, fractures, vesicles and microfractures constitute the permo--porous system that allows the understanding of various unconventional reservoirs in sub-surface, specially the volcanic reservoirs.