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Since many reservoirs do not allow direct observation due to their depth and/or difficulty of sampling, studies of analogs have been commonly used as a tool to understand the spatial distribution of reservoir properties. The Paraná Basin is 1.6 million km2 large and has two known petroleum systems. However, there are only 124 irregularly distributed wells drilled in the basin, among which 22 contain gas or oil shows and 10 have sub commercial accumulations. The Permo-Carboniferous Itararé Group, due to the exploration history, is the best exploratory target in the basin because it has thick intervals of sandstones with moderate to good reservoir quality and also because it often lies directly on gas-prone source rocks of the Devonian Ponta Grossa Formation. In order to increase knowledge about Itararé Group reservoirs, as well as to better understand its heterogeneities, this study aims to integrate petrophysical data with facies and facies associations using both outcrop and cores from shallow wells in southeastern Paraná Basin. By doing this it is expected to fill a gap of quantitative data in previous studies on reservoir analogs in the Itararé Group. Cores and outcrops were analyzed in sandstones in order to integrate surface and subsurface data, and to understand the lateral continuity according to stratigraphic correlations. Equipment such as gamma-ray spectrometer, portable x-ray fluorescence, and a minipermeameter were used for the acquisition of quantitative data. Sedimentological description of cores and outcrops as well as thin section description were also carried out. The facies with the greatest reservoir potential are medium to fine-grained, massive (Sm) and normally-graded (Sg) sandstones. In one outcrop locality (Rio dos Cedros), the Sg facies presents the best reservoir properties such as secondary porosity of 32% and average permeability of 1439 mD. The geochemical data allowed evaluating the gamma-ray variation in relation to chemical elements, such as iron oxide. In outcrop, API radiation is higher in relation to the cores, as well as Al 2 O 3 and Fe 2 O 3. These values are related to the large amount of intraclasts and cementation by iron oxides-hydroxides. Despite in the great amount of iron presents in the Rio dos Cedros samples, the porosity is mainly secondary, generated by the feldspars dissolution. The correlation between the cores and outcrops allowed the evaluation of the influences of mass transport deposits in the petrophysical properties of sandstones. In cores, sandstones interbedded with these deposits have high permeability, but it is not possible to evaluate its lateral continuity. In outcrops it was possible to observe that these deposits affect lateral continuity, permeability and porosity. We conclude that the best reservoir facies in the Itararé Group will be associated with sites within the basin that are away from the slope region and the influence of mass-transport processes. • The facies with greatest potential reservoir are Sm and Sg. • Sm and Sg are massive and graded sandstones and predominance of medium to fine grain size. • The API values are related to intraclasts and cementation by iron oxides-hydroxides. • Best potential reservoir located away from the influence of mass-transport processes. [ABSTRACT FROM AUTHOR]

Sedimentary composition studies on siliciclastic reservoirs and their relationship with sedimentary provenance have proved to be useful in hydrocarbon exploration, enabling the prognosis of reservoir quality and diagenetic models. However, unconventional terrigenous reservoirs in the Maracangalha Formation, Upper Cretaceous from Recôncavo Basin, have not yet been evaluated regarding sedimentary provenance and its control over reservoir quality. This study aims to define the provenance of the Maracangalha Formation sandstones and its control on the diagenetic processes affecting the reservoir quality. Based on petrography analysis and X-Ray Fluorescence data, it was possible to identify a granite-gneissic terrain under wet climate as the primary source area for quartz-feldspathic sandstones. The granite-gneissic terrains with predominantly felsic minerals, within in the surrounding Precambrian Terrains, represent a major source area for the quartz-feldspathic sandstones found in the Maracangalha Formation. These sources are characterized by significant contributions from recycled sedimentary and metasedimentary rocks, leading to the occurrence of litho and quartzose petrofacies. The high chemical-textural sediment maturity and paleoweathering dispersion, under semi-umid to semi-arid climates, may be a result of paleoclimatic changes and the variable residence times of the sediments in the dispersion routes or temporary storage. The mineral composition and primary texture of sandstones show a clear influence on diagenetic evolution, particularly in terms of mechanical compaction inhibition, by early cementation, and the generation of secondary porosity due to the dissolution of framework grains and early cements. Therefore, understanding the sedimentary provenance, composition, and diagenesis is crucial for predicting the quality of the reservoir and the compartmentalization of the Maracangalha Formation and its analogues. • Distinct provenances identified: granite-gneiss sources and recycled sources, added by intrabasinal sediment input. • Early Cretaceous paleotectonic changes in Northeast Brazil drove paleoweathering and climatic shifts in the source area. • Primary exploration targets are the feldspatho-quartzose sandstones, indicative of granite-gneissic contributions. • Sedimentary provenance dictate the Marancangalha Formation sandstone reservoirs' attributes, affecting reservoir quality. [ABSTRACT FROM AUTHOR]

The chronology of Pleistocene strandplains remains a challenge to this day. The lack of reliable geochronology methods arises from the fact that ages from the Pleistocene sequences are beyond radiocarbon age limit method and, sometimes, near the saturation limits to luminescence dating on quartz, which may introduce uncertainties in the results. Also, choosing different curve fits for the dose-response curve leads to geological incoherent results. In this paper, we evaluated three approaches on curve fit equations (single saturating exponential (SSE), double saturating exponential (DSE) or the SSE + Linear (E + L). We also compared the three scenarios with geological evidences such as sedimentary structures, like plane-parallel lamination, and the presence Ophiomorpha nodosa ichnofossil at Paranaguá and Superagüi strandplains, Southern Brazil. Since geological evidences indicate deposition under wave-dominated shoreline, the comparison to Quaternary sealevel curves restricts the beach ridges deposition to high relative sealevel intervals. Our results show that, despite being mathematically consistent, DSE and E + L curve fits lead to geological inconsistent results. The luminescence results using SSE curve fit are geologically consistent and suggest the occurrence of MIS 7e barrier on Paranaguá and Superagüi strandplains, the farther north occurrence of the Barreira II (195–220 ky) correspondent to the Rio Grande do Sul strandplain. However, we stress out that luminescence dating results near the saturation limit must be interpreted with caution, and preferably supported by other evidences. • Northern occurrence of 195–220 ky strandplain sequence at Southern Brazil. • Geological evidences helps choosing the best luminescence dating parameters. • Single saturating exponential dose-response curve fit shows geological coherent ages. [ABSTRACT FROM AUTHOR]

The present work presented the first dated paleosealevel indicators and new paleogeographic reconstructions of the Island of Trindade. All evidence for Holocene sealevels point to the elevations higher than the present in the age interval between 5.06 ka and 0.55 ka. The altitude and ages of the reconstructions are in good agreement with hindcast model curves and the empirical sealevel envelope for the mainland eastern and northeastern Brazilian coast. However, the position of paleo vermetid-reef indicates that sealevel was lower than eustatic elevation, suggesting an effect of island subsidence. In contrast to the Brazilian mainland coastal zone, where conspicuous evidences of Pleistocene highstands were recorded, no evidence of sealevels predating the Holocene has ever been observed on the island. This could be attributed to intense coastal erosion and log-term island subsidence. A volcanic edifice rising more than 5500 m above the ocean floor was built by magmatic activity that extended over the late Pliocene and early Pleistocene. After the cessation of volcanic build up, the island started to shrink due to subaerial and marine erosion. During Pleistocene sealevel lowstands, alluvial fans were formed beyond the present limits of emerged areas. They were enclosed within and preserved from erosion by the Middle to Late Pleistocene lava flows and pyroclastic deposits. During Late Pleistocene sealevel highstand, intense coastal erosion removed the distal parts of the alluvial fans. It is very likely that at that time the entire coast of the island experienced intense erosion and subsidence as deduced from the absence of Pleistocene coastal deposits, which are widespread along mainland Brazilian coast. The east coast of the island was dominated by high sea cliffs sculpted into volcanic rocks. A volcanic cone was subsequently formed, when the sealevel was lower than present during the Late Pleistocene to early Holocene. During the mid to late Holocene sealevel highstand the volcanic cone was partially eroded and a bay formed, where vermetid-reefs grow and sand beach deposits prograded until the bay was infilled. During the sealevel maximum, wave-cut terraces were formed and sea cliffs were active. During the lowering of the sealevel, cliffs became inactive and vermetid-reefs were eroded. Beach erosion and aeolian deflation presently prevails, indicating a low sediment supply. [ABSTRACT FROM AUTHOR]

The interaction between coastal drift-dependent features, such as spit and inlet systems and the dynamics of estuaries, under the effect of tides, produces significant changes in coastal barriers depositional architecture. Extreme events associated with these autogenic factors insert elements of variability into the depositional architecture of these deposits. OSL (Optically Stimulated Luminescence) dating in the Holocene barrier of Praia de Leste, in the southern region of Brazil, associated with GPR (Ground Penetrating Radar) subsurface surveys and stratigraphic profiles at outcrops, identified a pattern of retrogradational stacking and truncation in the beach ridges, formed by local patterns of erosion and deposition, between the last relative maximum sea level and the beginning of progradation of the Holocene barrier. The predominance of a longshore drift in an opposite direction to the current one between 5.1 ± 0.3 ka and 4.1 ± 0.3 ka is suggested by the migration of spits and the displacement of a paleo-inlet to the southwest, later abandoned during the slow and gradual fall of the relative sea level (RSL) and consequent diminution of the estuary tidal prism. • Climate changes at the Meghalayan chronozone modify oceanographic/tidal circulation patterns during the barrier's evolution. • Coastal drift inversions registered in the barrier's depositional architecture by the lateral migration of spits and inlets. • Retrogradational stacking produced by occurrence of extreme events. • Barrier progradation and spit/inlet migration characterized by OSL ages and sedimentary facies. [ABSTRACT FROM AUTHOR]