https://repositorio.ufba.br/handle/ri/7161 2026-05-02T07:47:45Z https://repositorio.ufba.br/handle/ri/42868 Título: Avaliação do potencial gerador de hidrocarbonetos e do paleoambiente deposicional da Formação Pirara, Bacia do Tacutu, Brasil. Autor(es): Pereira, Ismael Ramos Primeiro Orientador: Oliveira, Olívia Maria Cordeiro de Abstract: The present research focused on the geochemical study of rock samples (siltites, marls and shales) from the Pirara Formation, from the core obtained in the R-B0-SR-01 well drilled in the Tacutu Basin, Roraima State, Northern Brazil. This study is justified by the fact that, despite the volume of subsurface data (geophysical methods) and the few geochemical data (surface geochemistry) about the basin, a broader and more robust geochemical characterization of the organic matter is necessary for a better evaluation of the effective potential of the Pirara Formation for the generation of oil. Following this proposal, the research had as main objective: to geochemically characterize the rocks of the Pirara Formation regarding the potential for the generation of hydrocarbons and to estimate the thermal evolution and the conditions of the paleoenvironment of deposition. The studies involved analyzes of Total Organic Carbon (TOC); Pyrolysis-Rock-Eval (S1, S2, S3, Tmax, HI and OI); gas chromatography of Total Organic Extract (whole oil); saturated biomarkers and stable carbon isotopes. This research showed that: the levels of TOC, in the analyzed samples, are between 0 and 7.78%. The insoluble residue (RI) values ranged between 23.32% and 94.34%. The Rock-Eval pyrolysis data provided distinct characteristics among the analyzed samples, which, in general, showed an oil potential that varied from poor to very good, but only five samples had good oil potential, despite being considered residual values. due to high maturation. The values of IH and IO, despite being also residual, indicate the existence of types I, II and III kerogens. The gas chromatography analyzes of the organic extracts showed results with chromatogram patterns that represent light oil, partially biodegraded petroleum, and biodegraded petroleum. The percentages of the oil fractions (saturated, aromatics and NSO compounds) suggest that the organic matter of the samples from the Pirara Formation has a tendency of high thermal maturity (high percentage of the saturated fraction) and high degree of biodegradation (high percentage of the fraction NSO) for some samples. The results of the analysis of saturated biomarkers in all samples show features that suggest very high thermal maturity. The diagnostic reasons of the saturated biomarkers suggest that the organic matter that gave rise to the organic extracts is mostly from marine planktonic organisms (algae and bacteria) and lesser contribution from terrestrial organic matter. The depositional paleoenvironment is characterized as a transitional-marine environment with variable and variable salinity and suboxic/anoxic condition. The sedimentation was of the mixed type (siliciclastic and carbonate) and the kerogen has thermal maturity referring to the late window of oil generation. All samples present biomarkers indicative of biodegradation, but with evidence of mixing with oil generated by the same source rock at different times. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2022-07-25T00:00:00Z https://repositorio.ufba.br/handle/ri/38050 Título: Proposta metodológica utilizando simulação computacional para avaliar dinâmica de um derramamento de óleo e a dose na biota. Autor(es): Protasio, Laianne dos Santos Primeiro Orientador: Mendonça, Luis Felipe Ferreira de Abstract: Oil spills are one of the most impactful sources of marine pollution. The release of oil on the ocean surface can have potential environmental impacts. Due to these impacts caused by the oil exploration industry, knowing its behavior in the marine environment through studies of prevention, control and mitigation of oil spills is necessary. Many studies already make use of computational models and codes that have proved to be an important tool, with low computational cost, for risk management. The present work aims to analyze the output data of the oil dispersion model in the MEDSLICK-II software, through the case study of an oil spill in the Cumuruxatiba Basin region. This model calculates the transport and weathering of oil from data from a regional oceanic model, using a Lagrangian representation of the slick. Furthermore, we propose to observe the impact of oil on biota through the Monte Carlo computational code (MCNP), which estimates the transport of ionizing radiation from oil to biota in the oceanic environment. Our results showed that BC, with its acceleration associated with the summer months, can act as a physical barrier against zonal oil transport, and another important point is that the characteristic transport of western boundary currents can act as a strong agent spreader of elements associated with oil along the Brazilian coast. Furthermore, the Th-232 series stood out for presenting a significant contribution to the dose. However, a corrective action capable of removing Tl-208 would significantly reduce the effects of radiation on readily exposed populations, since this radionuclide stands out as the one that delivers the highest percentage of dose. This study is a first approximation in terms of the dose rate in the biota due to an oil spill. Thus, based on this information generated by the models, the aim is to create an application methodology for future studies of oil spills and their impact on coastal areas of the Brazilian coast. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2021-11-29T00:00:00Z https://repositorio.ufba.br/handle/ri/37758 Título: Paleoambiente deposicional e potencial gerador da formação Pojuca, Bacia do Recôncavo Autor(es): Miranda, Flavia Lima e Cima Primeiro Orientador: Santos, Luiz Carlos Lobato dos Abstract: The present work aimed to evaluate the paleodepositional conditions and the potential for hydrocarbon generation in the Pojuca Formation, Recôncavo Basin. For this, an organic geochemical characterization of 48 originating from a borehole (9-FBA-79-BA well) was carried out, near the city of Aramari. The levels of total organic carbon (TOC) vary from 1.24 to 4.85%, denoting the heterogeneity in the conditions of production and preservation of organic matter. The results of the Rock Eval pyrolysis indicated kerogen predominantly type I / II, and type III in some of it. The hydrocarbon source potential (S2) varied from poor to excellent (1.26 to 26.56 mg HC / g rock), low to good concentration of free hydrocarbons (S1) and maximum temperature (Tmax) of Rock Eval pyrolysis indicate thermal immaturity for hydrocarbon generation (<440oC), validated by the ratios pristane/ n-C17 and phytane/ n-C18> 1, C29 steranes S/S+R, αββ/αββ+ααα, TS/(TS+TM), and by the greater abundance of NSO compounds. Such results were consistent with the TOC values, making it possible to identify that those with the highest TOC and S2 values have high IH (hydrogen index) and low IO (oxygen index) values, corroborated by kerogen type I / II thus validating the quality of organic matter. As a sponsor with low source potential, they have high IO values and low IH values, proportionally, configuring type III kerogen (oxidized organic matter). Through the stable carbon isotopes analysis (-33.83 ‰ to -21.54 ‰) and saturated biomarkers it was possible to infer that the depositional paleoenvironment from the Pojuca Formation was lacustrine with variations in water salinity, indicated by the positivity of the δ 13C values of some samples suggesting an arid environment with a lot of water evaporation, and that, possibly, in some moments during the deposition of the Pojuca Formation, there was an influx of saline waters in the basin, favoring greater proliferation of algae in relation to bacteria. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2021-07-08T00:00:00Z https://repositorio.ufba.br/handle/ri/37718 Título: Potencial gerador dos folhelhos cretáceos e modelagem 1D na Sub-bacia Tucano Sul, Bahia, Brasil Autor(es): Alves, Ana Paula de Araújo Primeiro Orientador: Celino, Joil José Abstract: The Tucano Basin (TB) comprises the central portion of the Recôncavo-Tucano-Jatobá (RTJ) intracontinental rift that was aborted during the Eo-Aptian. Its origin is related to the crustal extension that occurred in the Early Cretaceous, with the fragmentation of the Gondwana supercontinent and the formation of the Atlantic Ocean. There are few published studies on the Tucano Basin regarding the generation of hydrocarbons. Thus, the present work aims to contribute to the knowledge of the generating potential of the southern compartment of this basin, through the evaluation of the shales of the Ilhas Group (which is undivided) and of the Candeias Formation in a well (TBO-1-BA) and the modeling 1D for hydrocarbon generation conditions. The data from this well were provided by the ANP, and then, the geochemical characterization of samples of these shales was carried out with data on TOC, pyrolysis and macerals containing kerogen. Well 1-TBO-1-BA is in the central-west portion of the basin with a depth of 3,598 m. The Ilhas Group has the highest TOC contents, reaching values of 2.6%, while the Candeias Formation reaches 1.4%. Regarding thermal maturity for the generation of hydrocarbons the samples of the Candeias Formation present greater maturity in relation to the Ilhas Group, which would make it a more interesting exploratory target, with Tmax values between 448 ºC and 451 ºC and %Ro between 0.84 and 0. 94%. Samples from the Ilhas Group range from immature at its top (Tmax = 432 ºC, Ro =0.55%) to mature at its base (Tmax = 450 ºC, Ro = 0.77%). The Van Krevelen type diagram classifies the kerogen contained in the shale samples from the two units as predominantly type II and III but evaluating itself with the set of maturity data and macerals made available by the ANP, it is suggested that there is a mixture of types I and II. For the construction of the basin's thermal and subsidence history, Schlumberger's Petromod software was used, inserting geological and geochemical data and the crust (4.0) and mantle (1.1) stretching factors in the Mckenzie module. As a result, the heat flow and subsidence curve in geological time is obtained. The heat flow variation for Well 1-TBO-1-BA in the initial phase of the rift was 32 mW/m2 (Barremian) reaching 57 mW/m2 at the end of the rift phase (Aptian), with an erosion thickness of the well of 500 meters (350 meters at the top of the São Sebastião Formation and 150 meters at the top of the Marizal Formation). The modeling results reinforced that the base shales of the Candeias Formation have greater potential for the generation of hydrocarbons than those of the Ilhas Group, with its greater potential for oil generation, since the Candeias Formation has reached greater maturity (paleo-temperatures reaching 148 ºC and Ro to approximately 1%), reaching a transformation rate of 48%, while in the Ilhas Group there was no transformation. It was evident that the generation process was predominant during the synrift phase in theBarremian-Aptian (128 to 124 Ma), demonstrating that the heat flow from the basin opening process is the predominant factor for the maturation of organic matter. To verify which conditions would be ideal for the shales of these units to generate high potential conditions, a hypothetical well (HP-1) mirrored in well 1-TBO-1-BA was modeled, modifying the depth conditions of the well(5.600 metros) and the mean values of TOC(Ilhas Group 2,0 %Ro, Candeias Formation 1,7 %Ro) and IH(Ilhas Group 650 mgHC/gCOT, Candeias Formation 550 mgHC/gCOT). With these changes, there were significant changes in the thermal maturation of the units and, consequently, in the transformation rates with gás generation. The Candeias Formation reached 2.3 %Ro and the Ilhas Group 1.4 %Ro, with the two units reaching a 100% transformation rate and this condition may be feasible, since the basin can reach a depth of 7,000 meters, indicating an important prospective potential for the low blocks of this sub-basin. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2022-03-08T00:00:00Z