Micro- and nano-pores in intrasalt, microbialite-dominated carbonate reservoirs, Ara Group, South-Oman salt basin.
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| Title: | Micro- and nano-pores in intrasalt, microbialite-dominated carbonate reservoirs, Ara Group, South-Oman salt basin. |
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| Authors: | Smodej, Jörg1 (AUTHOR) joerg.smodej@rwth-aachen.de, Reuning, Lars1 (AUTHOR), Becker, Stephan2 (AUTHOR), Kukla, Peter A.2 (AUTHOR) |
| Source: | Marine & Petroleum Geology. Jun2019, Vol. 104, p389-403. 15p. |
| Subjects: | Carbonate minerals, Carbonate reservoirs, Dolomite, Crystal texture, Confocal microscopy, Microporosity, Image analysis |
| Abstract: | Dolomitic microbialites form important exploration targets for the oil and gas industry in many parts of the world. It is known that a significant portion of their total porosity and potential storage capacity is formed by micropores. Despite their economic importance few studies attempted to characterize the micro-to nanoporosity in dolomitic microbialites. Recent advances in the field of microscopy now allow to image and analyze their pore systems on a hitherto unprecedented scale. This study evaluates pore systems in Neoproterozoic Ara-Group carbonates forming part of the deeply buried intra-salt A2C hydrocarbon play of the South-Oman Salt-Basin (SOSB). Micro- and nanoporosity there is hosted by aphanocrystalline and, to a minor extent, microcrystalline dolomite. Image analysis derived from broad-ion-beam milling and scanning-electron microscopy (BIB-SEM) of representative samples display a contribution between ∼50 and 100% from micro- and nanopores to total porosities which are up to ∼17%. The main diagenetic controls on microporosity in the A2C are the formation and preservation of primary or early diagenetic (aphanocrystalline) dolomite and the presence of evaporites, calcite and solid bitumen. Petrographic and petrophysical observations show good preservation of the original textural and geochemical attributes in most dolomite samples, even after burial to 5 km depth for the past 500 million years. This suggests a structurally and hydrodynamically isolated, rockbuffered system with a limited extent of cementation. Confocal laser-scanning microscopy (CLSM) reveals significant amounts of hydrocarbons which manifest as degenerated organic material in the carbonates. They originated from precursor bacterial organic matter in microbial laminite, thrombolite and peloidal source-rocks and might have prevented extensive recrystallization of the aphanocrystalline dolomite matrix and further cementation of the porespace. Primary dolomite might still be preserved in the A2C microbialites as petrographic observations reveal similarities in crystal sizes and the texture of euhedral aphanocrystalline dolomite as observed in comparable sedimentary systems. • Micro- and nanoporosity is hosted by microbial and grain-dominated carbonates. • Dolomite crystal size controls distribution of micro- and nanoporosity. • More than half of the total porosity (up to ∼17%) is micro- and nanoporosity. • Good preservation of original textural and geochemical attributes in dolomite. • Primary dolomite might still be preserved in the A2C microbialites. [ABSTRACT FROM AUTHOR] |
| Copyright of Marine & Petroleum Geology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 136253242 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Micro- and nano-pores in intrasalt, microbialite-dominated carbonate reservoirs, Ara Group, South-Oman salt basin. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Smodej%2C+Jörg%22">Smodej, Jörg</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> joerg.smodej@rwth-aachen.de</i><br /><searchLink fieldCode="AR" term="%22Reuning%2C+Lars%22">Reuning, Lars</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Becker%2C+Stephan%22">Becker, Stephan</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kukla%2C+Peter+A%2E%22">Kukla, Peter A.</searchLink><relatesTo>2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Marine+%26+Petroleum+Geology%22">Marine & Petroleum Geology</searchLink>. Jun2019, Vol. 104, p389-403. 15p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Carbonate+minerals%22">Carbonate minerals</searchLink><br /><searchLink fieldCode="DE" term="%22Carbonate+reservoirs%22">Carbonate reservoirs</searchLink><br /><searchLink fieldCode="DE" term="%22Dolomite%22">Dolomite</searchLink><br /><searchLink fieldCode="DE" term="%22Crystal+texture%22">Crystal texture</searchLink><br /><searchLink fieldCode="DE" term="%22Confocal+microscopy%22">Confocal microscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Microporosity%22">Microporosity</searchLink><br /><searchLink fieldCode="DE" term="%22Image+analysis%22">Image analysis</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Dolomitic microbialites form important exploration targets for the oil and gas industry in many parts of the world. It is known that a significant portion of their total porosity and potential storage capacity is formed by micropores. Despite their economic importance few studies attempted to characterize the micro-to nanoporosity in dolomitic microbialites. Recent advances in the field of microscopy now allow to image and analyze their pore systems on a hitherto unprecedented scale. This study evaluates pore systems in Neoproterozoic Ara-Group carbonates forming part of the deeply buried intra-salt A2C hydrocarbon play of the South-Oman Salt-Basin (SOSB). Micro- and nanoporosity there is hosted by aphanocrystalline and, to a minor extent, microcrystalline dolomite. Image analysis derived from broad-ion-beam milling and scanning-electron microscopy (BIB-SEM) of representative samples display a contribution between ∼50 and 100% from micro- and nanopores to total porosities which are up to ∼17%. The main diagenetic controls on microporosity in the A2C are the formation and preservation of primary or early diagenetic (aphanocrystalline) dolomite and the presence of evaporites, calcite and solid bitumen. Petrographic and petrophysical observations show good preservation of the original textural and geochemical attributes in most dolomite samples, even after burial to 5 km depth for the past 500 million years. This suggests a structurally and hydrodynamically isolated, rockbuffered system with a limited extent of cementation. Confocal laser-scanning microscopy (CLSM) reveals significant amounts of hydrocarbons which manifest as degenerated organic material in the carbonates. They originated from precursor bacterial organic matter in microbial laminite, thrombolite and peloidal source-rocks and might have prevented extensive recrystallization of the aphanocrystalline dolomite matrix and further cementation of the porespace. Primary dolomite might still be preserved in the A2C microbialites as petrographic observations reveal similarities in crystal sizes and the texture of euhedral aphanocrystalline dolomite as observed in comparable sedimentary systems. • Micro- and nanoporosity is hosted by microbial and grain-dominated carbonates. • Dolomite crystal size controls distribution of micro- and nanoporosity. • More than half of the total porosity (up to ∼17%) is micro- and nanoporosity. • Good preservation of original textural and geochemical attributes in dolomite. • Primary dolomite might still be preserved in the A2C microbialites. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Marine & Petroleum Geology is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.marpetgeo.2019.03.036 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 15 StartPage: 389 Subjects: – SubjectFull: Carbonate minerals Type: general – SubjectFull: Carbonate reservoirs Type: general – SubjectFull: Dolomite Type: general – SubjectFull: Crystal texture Type: general – SubjectFull: Confocal microscopy Type: general – SubjectFull: Microporosity Type: general – SubjectFull: Image analysis Type: general Titles: – TitleFull: Micro- and nano-pores in intrasalt, microbialite-dominated carbonate reservoirs, Ara Group, South-Oman salt basin. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Smodej, Jörg – PersonEntity: Name: NameFull: Reuning, Lars – PersonEntity: Name: NameFull: Becker, Stephan – PersonEntity: Name: NameFull: Kukla, Peter A. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 06 Text: Jun2019 Type: published Y: 2019 Identifiers: – Type: issn-print Value: 02648172 Numbering: – Type: volume Value: 104 Titles: – TitleFull: Marine & Petroleum Geology Type: main |
| ResultId | 1 |
