Caracterização paleoambiental e avaliação do potencial gerador de hidrocarbonetos da Formação Cunga na área de Cabo de São Braz, Bacia do Kwanza, Angola
DOI:
https://doi.org/10.70369/8abz8008Palavras-chave:
Formação Cunga, Bacia de Kwanza, geoquímica orgânica, rocha geradora, pirólise Rock-Eval, maturação térmicaResumo
A Formação Cunga é uma formação geológica localizada na porção onshore da Bacia do Kwanza, data do Eoceno e é composta predominantemente por folhelhos e argilitos castanhos a preto, margas, calcários, siltitos e arenitos. Com vista à caracterização paleoambiental e avaliação do potencial gerador de hidrocarbonetos da Formação Cunga na Região do Cabo de São Braz, foram realizadas análises de difração de raios X (DRX - 24 amostras), análises geoquímicas (Carbono Orgânico Total - COT, e Pirólise Rock-Eval) e avaliação dos palinomorfos. A partir das análises de DRX, foi possível identificar as associações minerais, tendo sido encontrados, com predominância, quartzo, albita, microclina, muscovita e ortoclásio nas amostras analisadas. A análise das lâminas palinológicas revelou a presença de palinomorfos marinhos, nomeadamente dinoflagelados e foraminíferos, bem como palinomorfos continentais, tais como fungos e esporos. A análise de COT permitiu quantificar a matéria orgânica, apresentado valores entre 0,14% e 7,52%. A análise de pirólise Rock-Eval forneceu informações sobre a qualidade da matéria orgânica presente nas amostras, revelando a ocorrência dos querogênio tipos II, II/III e III. Adicionalmente, o parâmetro Tmax foi utilizado para avaliar o grau de maturação térmica das amostras, registando-se valores entre 417 °C e 431 °C. Da interpretação dos resultados, determinou-se que a Formação Cunga na Zona de Cabo de São Braz foi depositada em um ambiente sedimentar marinho costeiro a nerítico. A Formação Cunga apresenta um bom potencial para a geração de gás e petróleo; contudo, devido à maturação térmica insuficiente, não se tem revelado uma rocha geradora eficaz.
Referências
Adegoke, A.K., Wan, H.A., Hakimi, M.H., Yandoka, B.M.S., Mustapha, K.A., and Aturamu, A.O., 2014, Trace elements geochemistry of kerogen in Upper Cretaceous sediments, Chad (Bornu) Basin, northeastern Nigeria: origin and paleoredox conditions. Journal of African Earth Sciences, v. 100, p. 675-683, doi: https://doi.org/10.1016/j.jafrearsci.2014.08.014.
Ader, M., Macouin, M., Trindade, R.I.F., Hadrien, M.H., Yang, Z., Sun, Z., and Besse, J., 2009, A multilayered water column in the Ediacaran Yangtze platform? Insights from carbonate and organic matter paired δ13C: Earth and Planetary Science Letters, v. 288, n. 1-2, p. 213-227, doi: https://doi.org/10.1016/j.epsl.2009.09.024 Get rights and content.
Al-Areeq, N.M., and Albaroot, M., 2019, Source Rocks Evaluation and Thermal Maturity of the Dhamar Ali Field, Sab’Atayn Basin, Yemen: Asian Journal of Science and Technology, v. 10, n. 1, p. 9364-9374.
Albriki, K., Wang, F., Li, M. and El Zaroug, R., 2021, Source rock maturity evaluation and its implication for regional petroleum charge, Sirt Basin, Libya: Insights from regional geochemical assessments and modelling study: Journal of African Earth Sciences, v. 176, p. 1-25, doi: https://doi.org/10.1016/j.jafrearsci.2021.104114.
Beglinger, S.E., Doust, H., and Cloetingh, S., 2012, Relating petroleum system and play development to basin evolution: West African South Atlantic basins: Marine and Petroleum Geology, v. 30, n. 1, p. 1-25, doi: https://doi.org/10.1016/j.marpetgeo.2011.08.008.
Boggs Jr., S., 1987, Principles of sedimentology and stratigraphy, 1st ed., Columbus, Merrill Publishing Company, 784 p.
Brognon, G.P. and Verrier, G.R., 1966, Oil and Geology in Kwanza Basin of Angola: AAPG Bulleti, v. 50, n. 1, p. 108-158, doi: https://doi.org/10.1306/5D25B471-16C1-11D7-8645000102C1865D.
Brownfield, M.E., and Charpentier, R.R., 2006, Geology and total petroleum systems of the West-central coastal province (7203), West Africa: U.S. Geological Survey Bulletin, v. 2207-B, p. 1-52, doi: https://doi.org/10.3133/b2207B.
Burwood, R., 1999, Angola: source rock control for Lower Congo Coastal and Kwanza Basin petroleum systems: Geological Society Special Publications, v. 153, p. 181-194, doi: https://doi.org/10.1144/GSL.SP.1999.153.01.12.
Cacama, M.S.J.B., 2021, Avaliação do potencial da Formação Cunga (Bacia do Kwanza) como resrvatório não convencional: implicações no armazenamento de dióxido de carbono, Porto, Portugal [Thesis]: Repositório Institucional da Universidade Fernando Pessoa, Portugal.
Catuneanu, O., 2006, Principles of sequence stratigraphy. Amsterdam: Elsevier.
Climate Council of Australia, 2015, Unburnable carbon: Why we need to leave fossil fuels in the ground. https://climatecouncil.org.au/uploads/a904b54ce67740c4b4ee2753134154b0.pdf. (acessed August 2024).
Chiaghanam, O.I., Chiadikobi, K.C., Ikegwuonwu, A.O., Onyemesili, O.C., and Yikarebogha, Y., 2014, Source Rock Potential and thermal maturity of the Eocene Nanka Formation (Ameki Group) in Anambra Basin: an appraisal of Ogbunike reference locality, south eastern Nigeria: IOSR Journal of Applied Geology and Geophysics, v. 2, p. 11-17, doi: https://doi.org/10.9790/0990-0231117.
Demercian, S., Szatmari, P., and Cobbold, P.R., 1993, Style and pattern of salt diapirs due to thin-skinned gravitational gliding, Campos and Santos basins, offshore Brazil: Tectonophysics, v. 228, n. 3-4, p. 393-433, doi: https://doi.org/10.1016/0040-1951(93)90351-J.
Deng, Q., Zhao, G., Wang, H., Cheng, B., and Liao, Z., 2023, Distribution and geochemical significance of trace elements in kerogens from Ediacaran-Lower Cambrian strata in South China: Acta Geochimica, v. 42, p. 50-62, doi: https://doi.org/10.1007/s11631-022-00571-w.
Duval, B., Cramez, C., and Jackson, M.P.A., 1992, Raft tectonics in the Kwanza Basin, Angola: Marine and Petroleum Geology, v. 9, p. 389-404 doi: https://doi.org/10.1016/0264-8172(92)90050-O.
Einsele, G.,1992, Sedimentary Basins: Evolution, Facies, and Sediment Budget. Springer‑Verlag, Berlin, doi: https://doi.org/10.1007/978-3-662-04029-4.
Embry, A.F., and Johannessen, E.P., 1992, T-R sequence stratigraphy, facies analysis and reservoir distribution in the Western Canada Sedimentary Basin, in Macqueen, R.W. and Leckie, D.A., eds., Canadian Society of Petroleum Geologists Memoir, 17 pp, p. 485-496.
Espitalié, J., Laporte, J.L., Madec, M., Marquis, F., Leplat, P., Paulet, J., and Boutefeu, A.,1977, Methode rapide de caracterisation des roches mères, de leur potential petrolier et de leur degré d'evolution: Revue de l'Institut Français du Petrole, v. 32, p. 23-42.
Fort, X., Brun, J.P., and Chauvel, F., 2004, Salt tectonics on the Angolan margin, synsedimentary deformation processes: AAPG Bulletin, v. 88, n.11, p.1523-1544, doi: https://doi.org/10.1306/06010403012.
Horn, M.K., 1980. The habitat of oil and gas on continental margins, in Proceedings of the South East Asia Petroleum Exploration Society, 5th, p. 23-62.
Hudec, M.R., and Jackson, M.P.A., 2002, Regional restoration across the Kwanza Basin, Angola: salt tectonics triggered by repeated uplift of a metastable passive margin: AAPG Bulletin, v. 88, n. 7, p. 971-990, doi: https://doi.org/10.1306/02050403061.
Hunt, J.M., 1996, Petroleum Geochemistry and Geology, 2ed, W. H. Freeman and Company: New York, 743 p., https://pt.scribd.com/document/816396237/PetroleumGeochemistry-and-Geology-by-John-M-Hunt. (acessed August 2024)
Jian-Ping, L., Xiao-hua, P., Zuo-ji, T., Yong-jin, C., and Lun-kun, W., 2008, Petroleum geology and resources in West Africa: an overview: Petrololeum Exploration and Development, v. 35, n. 3, p. 378-384, doi: https://doi.org/10.1016/S1876-3804(08)60086-5.
Karner, G.D., Driscoll, N.W., and Barker, D.H.N., 2003, Syn-rift regional subsidence across the West African continental margin: the role of lower plate ductile extension: Geological Society of London Special Publication, v. 207, n. 1, p. 105-129 doi: https://doi.org/10.1144/GSL.SP.2003.207.6.
Kornpihl, K., Tewari, S., Uzcategui Salazar, M., and Rathee, D., 2024, Petroleum systems modelling in the Kwanza Basin, offshore Angola, in EAGE Annual Conference & Exhibition, 85th, v. 2024, p. 1-5, doi: 10.3997/2214-4609.202410413.
Letouzey, J., Colletta, B., Vially, R., and Chermette, J.C., 1995, Evolution of salt-related structures in compressional settings, in Jackson, M. P. A., Roberts, D. G., and Snelson, S., eds., Salt tectonics, a global perspective: AAPG Memoir, v. 65, p. 41-60, doi: https://doi.org/10.1306/M65604C3.
Lundin, E.R., 1992, Thin-skinned extensional tectonics on a salt detachment, northern Kwanza basin, Angola: Marine Petroleum Geology, v. 9, n.4, p. 405-411 doi: https://doi.org/10.1016/0264-8172(92)90051-F.
Mohammed, M., 2018, Oil production and economic growth in Angola: International Journal of Energy Economics and Policy, v. 8, n. 2, p. 127-131.
Morley, C.K., and Guerin, G., 1996, Comparison of gravity-driven deformation styles and behavior associated with mobile shales and salt: Tectonics, v. 15, n. 6, p. 1154-1170, doi: https://doi.org/10.1029/96TC01416.
Peel, F.J., Travis, C.J., and Hossack, J.R., 1995, Genetic structural provinces and salt tectonics of the Cenozoic offshore U.S. Gulf of Mexico: A preliminary analysis, in Jackson, M.P.A., Roberts, D.G., and Snelson, S., eds., Salt tectonics, a global perspective: AAPG Memoir 65, p. 153-175, doi: https://doi.org/10.1306/M65604C7.
Pereira, Z., Mendes, M., Rodrigues, C., Mulanda, N., Cacama, M., and Nsungani, P.C., 2021, Dinoflagellate cyst assemblages of the Cunga - Quifangondo cenozoic formations in the Cabo São Brás section, Kwanza Basin (Angola): towards a first stratigraphic and paleoenvironmental interpretation: Revue de Micropaléontologie, v. 72, n. 1-20, doi: https://doi.org/10.1016/j.revmic.2021.100516.
Peters, K.E., and Cassa, M.R., 1994, Applied source rock geochemistry, in Magoon, L.B., and Dow, W., eds., The Petroleum System - From Source to Trap. Tulsa: American Association of Petroleum Geologists Memoir, v. 60, p. 93-120, doi: https://doi.org/10.1306/M60585C5.
Posamentier, H.W., and Allen, G.P., 1999, Siliciclastic sequence stratigraphy: concepts and applications: SEPM Concepts in Sedimentology and Paleontology, n. 7, Tulsa, doi: https://doi.org/10.2110/csp.99.07.
Rodrigues, C.F.A. et al., 2021, Preliminary late Miocene palynomorph assemblages from the Quifangondo and Luanda formations, Onshore Kwanza Basin, Angola: Journal of African Earth Sciences, v. 178, p. 1-20, doi: https://doi.org/10.1016/j.jafrearsci.2021.104141.
Rodrigues, C., Fernandes, P., Pereira, Z. and Barata, S., 2017, Source rocks of the onshore Kwanza Basin - a new geochemical approach, in EAGE/ASGA Petroleum Exploration Workshop, 1st, Luanda, Angola, pp 1-5, doi: https://doi.org/10.3997/2214-4609.201702362.
Schiefelbein, C.F., Zumberge, J.E., Cameron, N.R., and Brown, S.W., 1999, Petroleum systems in the South Atlantic margins, in Cameron, N.R., Bate, R.H., and Clure, V.S., eds., The Oil and Gas Habitats of the South Atlantic: London Geological Society Special Publications, v. 153, p. 169-179, doi: https://doi.org/10.1144/GSL.SP.1999.153.01.11.
Serié, C., Huuse, M., Schødt, N.H., Brooks, J.M., and Williams, A., 2016, Subsurface fluid flow in the deep-water Kwanza Basin, offshore Angola: Basin Research, v. 29, n. 2, p. 149-179, doi: https://doi.org/10.1111/bre.12169.
Silva, A.L., 2013, Caracterização mineralógica por difracção de raios-X e determinação de terras raras por ICP-MS de Rochas da Região Sul da Bahia [dissertion]: Minas Gerais: Universidade Federal de Minas Gerais, 100 p., https://repositorio.ufmg.br/handle/1843/BUBD-97XP2T (acessed July 2024).
Stark, D.M., et al., 1991, Well Evaluation Conference of Angola, p. 1-352.
Tahoun, S.S., Deaf, A.S., and Mansour, A., 2017, Palynological, palaeoenvironmental and sequence stratigraphical analyses of a Turonian-Coniacian sequence, Beni Suef Basin, Eastern Desert, Egypt: implications of Pediastrum rhythmic signature: Marine and Petroleum Geology, v. 88, p. 871-887, doi: https://doi.org/10.1016/j.marpetgeo.2017.09.026.
Tissot, B.P., and Welte, D.H., 1984, Petroleum formation and occurrence: a new approach to oil and gas exploration: New York, Heidelberg Springer Verlang, 702 p., doi: https://doi.org/10.1007/978-3-642-87813-8.
Total-Sonangol, 1987. Carte Geologique du Bassin du Kwanza. Angola 1, 250 000.
Tribovillard, N., Algeo, T.J., Lyons, T., and Riboulleau, A., 2006, Trace metals as paleoredox and paleoproductivity proxies: an update: Chemical Geology, v. 232, n. 1-2, p. 12-32, doi: https://doi.org/10.1016/j.chemgeo.2006.02.012
Tyson, R.V., 1995, Sedimentary Organic Matter: Organic Facies and Palynofacies: Chapman & Hall, London, 615 p.
Wood, G.D., Gabriel, A.M. and Lawson, J.C., 1996, Palynological techniques processing and microscopy: American Association of Stratigraphic Palynologists Foundation, v. 1, p. 29-50.
Wu, S., Bally, A.W., and Cramez, C., 1990, Allochtonous salt, structure and stratigraphy of the northeastern Gulf of Mexico. Part II Structure: Marine and Petroleum Geology, v. 7, n. 4, p. 334-370, doi: https://doi.org/10.1016/0264-8172(90)90014-8.
Xu, N., Chen, M., Zhou, K., Wang, Y., Yin, H., and Chen, Z., 2014, Retention of phosphorus on calcite and dolomite: Speciation and modeling: RSC Advances, v. 4, n. 66, p. 35205-35214, doi: https://doi.org/10.1039/C4RA05461J.
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