The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)

The Napo Formation of Lower-Middle Cretaceous age in the Oriente basin, Ecuador, is an important sandstone reservoir. The formation is buried at a depth of 1500 m in the eastern part of the basin and down to 3,100 m in the western part. The sandstones display higher porosity values (av. 20%) than ot...

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Authors: Estupiñan, J., Marfil, R., Delgado, A., Permanyer i Bastardas, Albert
Format: article
Status:Published version
Publication Date:2007
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/16872
Online Access:https://hdl.handle.net/2445/16872
Access Level:Open access
Keyword:Roques sedimentàries
Diagènesi
Geoquímica
Equador
Sedimentary rocks
Diagenesis
Geochemistry
Ecuador
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spelling The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)Estupiñan, J.Marfil, R.Delgado, A.Permanyer i Bastardas, AlbertRoques sedimentàriesDiagènesiGeoquímicaEquadorSedimentary rocksDiagenesisGeochemistryEcuadorThe Napo Formation of Lower-Middle Cretaceous age in the Oriente basin, Ecuador, is an important sandstone reservoir. The formation is buried at a depth of 1500 m in the eastern part of the basin and down to 3,100 m in the western part. The sandstones display higher porosity values (av. 20%) than other reservoirs in the region. These sandstones were deposited in fluvial, transitional and marine environments, and they are fine to medium grained quartzarenites and subarkoses. The principal cements are carbonates, quartz overgrowth and kaolin, with scarce amounts of pyrite-pyrrhotite and chlorite. Carbonate cements include: Eogenetic siderite (S1), mesogenetic and post-compactional calcite, Fe-dolomite, ankerite and siderite (S2). Early siderite and chlorite helped to retain porosity by supporting the sandstone framework against compaction. Dissolution of feldspars and carbonate cements are the main mechanism for secondary porosity development during mesodiagenesis. The high intergranular volume (IGV) of the sandstones indicates that cementation is the predominant contributor to porosity loss in the reservoir and that the precipitation of the carbonate cement occurred in early and late diagenetic stages. The stable-isotope composition of the S1 siderite is consistent with precipitation from meteoric waters in fluvial sandstones, and from mixed meteoric and marine waters in transitional sandstones. The low values of some of these carbonate phases reflect the replacement and recristalization from S1 to S2 siderite at deep burial and high temperature. Textural evidence, together with a low Sr content, also suggests that siderite (S1) in fluvial environment is an early cement that precipitated from meteoric waters, near the sediment/water interphase, followed by the generation of calcite with a higher Fe and Mg content. However, due to this higher Mg content, siderite S2 could have precipitated as a result of the thermal descarboxilation of the Mg rich organic matter. The progressive decrease in values in all carbonate cements could be related to the continued precipitation at different temperatures and burial depth.Universitat de Barcelona (UB). Institut de Ciències de la Terra Jaume Almera (ICTJA). Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDEA). Universitat Autonònoma de Barcelona (UAB). Consejo Superior de Investigaciones Científicas (CSIC)201120112007info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion19 p.application/pdfhttps://hdl.handle.net/2445/16872Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésReproducció del document publicat a http://dx.doi.org/10.1344/105.000000312Geologica Acta, 2007, vol. 5, núm. 1, p. 89-107http://dx.doi.org/10.1344/105.000000312cc by-sa (c) Estupiñan et al., 2007http://creativecommons.org/licenses/by-sa/3.0/es/info:eu-repo/semantics/openAccessoai:recercat.cat:2445/168722026-05-29T05:05:01Z
dc.title.none.fl_str_mv The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
title The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
spellingShingle The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
Estupiñan, J.
Roques sedimentàries
Diagènesi
Geoquímica
Equador
Sedimentary rocks
Diagenesis
Geochemistry
Ecuador
title_short The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
title_full The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
title_fullStr The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
title_full_unstemmed The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
title_sort The impact of carbonate cements on the reservoir quaility in the Napo Fm sandstones (Cretaceous Oriente Basin, Ecuador)
dc.creator.none.fl_str_mv Estupiñan, J.
Marfil, R.
Delgado, A.
Permanyer i Bastardas, Albert
author Estupiñan, J.
author_facet Estupiñan, J.
Marfil, R.
Delgado, A.
Permanyer i Bastardas, Albert
author_role author
author2 Marfil, R.
Delgado, A.
Permanyer i Bastardas, Albert
author2_role author
author
author
dc.subject.none.fl_str_mv Roques sedimentàries
Diagènesi
Geoquímica
Equador
Sedimentary rocks
Diagenesis
Geochemistry
Ecuador
topic Roques sedimentàries
Diagènesi
Geoquímica
Equador
Sedimentary rocks
Diagenesis
Geochemistry
Ecuador
description The Napo Formation of Lower-Middle Cretaceous age in the Oriente basin, Ecuador, is an important sandstone reservoir. The formation is buried at a depth of 1500 m in the eastern part of the basin and down to 3,100 m in the western part. The sandstones display higher porosity values (av. 20%) than other reservoirs in the region. These sandstones were deposited in fluvial, transitional and marine environments, and they are fine to medium grained quartzarenites and subarkoses. The principal cements are carbonates, quartz overgrowth and kaolin, with scarce amounts of pyrite-pyrrhotite and chlorite. Carbonate cements include: Eogenetic siderite (S1), mesogenetic and post-compactional calcite, Fe-dolomite, ankerite and siderite (S2). Early siderite and chlorite helped to retain porosity by supporting the sandstone framework against compaction. Dissolution of feldspars and carbonate cements are the main mechanism for secondary porosity development during mesodiagenesis. The high intergranular volume (IGV) of the sandstones indicates that cementation is the predominant contributor to porosity loss in the reservoir and that the precipitation of the carbonate cement occurred in early and late diagenetic stages. The stable-isotope composition of the S1 siderite is consistent with precipitation from meteoric waters in fluvial sandstones, and from mixed meteoric and marine waters in transitional sandstones. The low values of some of these carbonate phases reflect the replacement and recristalization from S1 to S2 siderite at deep burial and high temperature. Textural evidence, together with a low Sr content, also suggests that siderite (S1) in fluvial environment is an early cement that precipitated from meteoric waters, near the sediment/water interphase, followed by the generation of calcite with a higher Fe and Mg content. However, due to this higher Mg content, siderite S2 could have precipitated as a result of the thermal descarboxilation of the Mg rich organic matter. The progressive decrease in values in all carbonate cements could be related to the continued precipitation at different temperatures and burial depth.
publishDate 2007
dc.date.none.fl_str_mv 2007
2011
2011
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/16872
url https://hdl.handle.net/2445/16872
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a http://dx.doi.org/10.1344/105.000000312
Geologica Acta, 2007, vol. 5, núm. 1, p. 89-107
http://dx.doi.org/10.1344/105.000000312
dc.rights.none.fl_str_mv cc by-sa (c) Estupiñan et al., 2007
http://creativecommons.org/licenses/by-sa/3.0/es/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc by-sa (c) Estupiñan et al., 2007
http://creativecommons.org/licenses/by-sa/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 19 p.
application/pdf
dc.publisher.none.fl_str_mv Universitat de Barcelona (UB). Institut de Ciències de la Terra Jaume Almera (ICTJA). Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDEA). Universitat Autonònoma de Barcelona (UAB). Consejo Superior de Investigaciones Científicas (CSIC)
publisher.none.fl_str_mv Universitat de Barcelona (UB). Institut de Ciències de la Terra Jaume Almera (ICTJA). Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDEA). Universitat Autonònoma de Barcelona (UAB). Consejo Superior de Investigaciones Científicas (CSIC)
dc.source.none.fl_str_mv Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812455

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