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Previous issue date: 2014-06-04 / Universidade Federal do Rio Grande do Norte / The Rio do Peixe Basin represents a main basin of northeastern Brazil and pioneering work positioned the rocks of this basin in the Early Cretaceous. However, a recent study, based on integrated pollen analysis from three wells, found an unprecedented siliciclastic sedimentary section, in the region, of early Devonian age. Therefore, the present study aims a detailed petrographic and petrological analysis of this devonian section, in the Rio do Peixe Basin and proposes a diagenetic evolution, to understand the characteristics of the porous system, identify the main reservoir petrofacies with the main factors impacting on the quality of these rocks as reservoirs and a quick study on the provenance of this section. The petrographic study was based on samples obtained from subsurface and surface. The diagenetic evolution of petrofacies and its identification were based only on subsurface samples and the study of provenance was based on surface samples. The thin sections were prepared from sandstones, pelites and sandstones intercalated with pelites. The original detrital composition for this section is arcosean and the main diagenetic processes that affected these rocks occur in various depths and different conditions, which resulted in extensive diagenetic variety. The following processes were identified: early fracture and healing of grains; albitization of K-feldspar and plagioclase; siderite; precipitation of silica and feldspar; mechanical infiltration of clay and its transformation to illite/esmectite and illite; autigenesis of analcime; dissolution; autigenesis of chlorite; dolomite/ferrous dolomite/anquerite; apatite; calcite; pyrite; titanium minerals and iron oxide-hidroxide. The occurrence of a recently discovered volcanism, in the Rio do Peixe Basin, may have influenced the diagenetic evolution of this section. Three diagenetic stages affected the Devonian section: eo, meso and telodiagenesis. This section is compositionally quite feldspathic, indicating provenance from continental blocks, between transitional continental and uplift of the basement. From this study, we observed a wide heterogeneity in the role of the studied sandstones as reservoirs. Seven petrofacies were identified, taking into account the main diagenetic constituent responsible for the reduction of porosity. It is possible that the loss of original porosity was influenced by intense diagenesis in these rocks, where the main constituent for the loss of porosity are clays minerals, oxides and carbonate cement (calcite and dolomite) / A Bacia do Rio do Peixe corresponde a uma das principais bacias interiores do Nordeste do Brasil e trabalhos pioneiros posicionaram as rochas pertencentes a esta bacia, no Cret?ceo Inferior. Entretanto, um estudo mais recente, baseado na an?lise palinol?gica integrada entre tr?s po?os, verificou a exist?ncia de uma se??o sedimentar silicicl?stica, in?dita na regi?o, de idade eodevoniana. Portanto, o presente trabalho tem como objetivo realizar uma an?lise petrogr?fica e petrol?gica detalhada dessa se??o devoniana rec?m-descoberta na Bacia do Rio do Peixe e sugerir uma evolu??o diagen?tica, a fim de auxiliar no entendimento das caracter?sticas do sistema poroso, identificar as principais petrof?cies de reservat?rios, juntamente com os principais fatores impactantes na qualidade das mesmas e um breve estudo sobre a proveni?ncia dos sedimentos desta bacia. O estudo petrogr?fico foi baseado em amostras de subsuperficie e superf?cie, tendo a interpreta??o da evolu??o diagen?tica e a identifica??o das petrof?cies sido baseadas, apenas, nas amostras de subsuperf?cie. As l?minas petrogr?ficas foram confeccionadas a partir de arenitos, pelitos e arenitos intercalados por pelitos. A composi??o detr?tica original dessa se??o ? arcoseana e os principais processos diagen?ticos que a afetaram ocorreram em diversas profundidades e diferentes condi??es, o que resultou na grande variedade diagen?tica de processos: faturamento precoce e cicatriza??o de gr?os; albitiza??o dos K-feldspatos e plagiocl?sios; siderita; precipita??o de s?lica e feldspato; infiltra??o mec?nica de argila e transforma??o da mesma em ilita/esmectita e ilita; analcima; autig?nese de analcima; dissolu??o; precipita??o de caulinita; compacta??o mec?nica e qu?mica; autig?nese de clorita, dolomita/dolomita ferrosa/anquerita, apatita, calcita, pirita, minerais de tit?nio e ?xido/hidr?xido de ferro. A ocorr?ncia de vulcanismo rec?m-descoberto na Bacia do Rio do Peixe pode ter influenciado a evolu??o diagen?tica desta se??o. Foram identificados tr?s est?gios diagen?ticos: eo-, meso- e telodiag?nese. Essa se??o ? composicionalmente bastante feldsp?tica, indicando proveni?ncia de blocos continentais, entre o continental transicional a soerguimento do embasamento. A partir desse estudo, foi poss?vel verificar uma heterogeneidade no papel como reservat?rio dos arenitos estudados, sendo poss?vel a separa??o de sete petrof?cies, identificadas a partir do principal constituinte diagen?tico respons?vel pela redu??o da porosidade. A perda da porosidade original foi influenciada pela diag?nese intensa nessas rochas, sobretudo pela autig?nese de argilominerais, ?xidos e carbonatos (calcita e dolomita)
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13003 |
| Date | 04 June 2014 |
| Creators | Silva, Isabelle Teixeira da |
| Contributors | CPF:83933212715, http://lattes.cnpq.br/0930845549110627, Ros, Luiz Fernando de, CPF:38166550091, http://lattes.cnpq.br/9685540396391811, Srivastava, Narendra Kumar, CPF:22232591468, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4780135Y7, Vieira, Marcela Marques |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia do Petr?leo, UFRN, BR, Pesquisa e Desenvolvimento em Ci?ncia e Engenharia de Petr?leo |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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