Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM
Matrix-related pores play a significant role in controlling hydrocarbon production in organic-rich shales. Multiple matrix-related pore types of typical marine shales in the Sichuan Basin have been visually investigated and identified by transmission electron microscopy (TEM) on ultra-thin sections...
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| Format: | Article |
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MDPI AG
2022-11-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/23/4135 |
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| author | Jinxuan Han Hongjian Zhu Yanjun Lu Su Yang Manping Yang Erxiu Shi Yu Qi |
| author_facet | Jinxuan Han Hongjian Zhu Yanjun Lu Su Yang Manping Yang Erxiu Shi Yu Qi |
| author_sort | Jinxuan Han |
| collection | DOAJ |
| description | Matrix-related pores play a significant role in controlling hydrocarbon production in organic-rich shales. Multiple matrix-related pore types of typical marine shales in the Sichuan Basin have been visually investigated and identified by transmission electron microscopy (TEM) on ultra-thin sections and by focused ion beam-scanning electron microscopy (FIBSEM) on polished sections. OM-hosted pores seem universal and range in sizes from below 1 nm to hundreds of nanometers and they are not homogeneously developed and distributed, which is mainly determined by thermal maturity and OM composition. Mineral-hosted pores are defined by mineral frameworks and occur in open spaces related to ductile or rigid grain fabric. The four porous mineral types that occur are clay intrapores, carbonate solvopores, pyrite interpores, and quartz interpores, and they range in size from less than 1 nm to more than several microns. Aggregate-hosted pores are predominantly associated with clay-organic aggregates, pyrite-organic aggregates, clay-pyrite aggregates, and clay-organic-pyrite aggregates. The most common aggregate-hosted pore networks are defined by clay-organic aggregates, and the pores are largely developed between the clay and organic layers and may be the important adsorption spaces for methane. Fracture-related pores include microchannels and microfractures of various sizes and shapes and they could play a key role in providing hydrocarbon migration pathways. FIBSEM and TEM show direct evidence that OM-hosted pores and fracture-related pores contribute more to the effective pore network and the excellent reservoir quality, whereas poor reservoir quality may come from aggregate-hosted pores. |
| first_indexed | 2024-03-09T17:39:05Z |
| format | Article |
| id | doaj.art-cfdca1e3a82047f083324ac525b64a1f |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T17:39:05Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-cfdca1e3a82047f083324ac525b64a1f2023-11-24T11:46:06ZengMDPI AGNanomaterials2079-49912022-11-011223413510.3390/nano12234135Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEMJinxuan Han0Hongjian Zhu1Yanjun Lu2Su Yang3Manping Yang4Erxiu Shi5Yu Qi6School of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaSchool of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaSchool of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaPetroleum Engineering Technology Research Institute, Sinopec Southwest Oil and Gas Company, Deyang 618000, ChinaSchool of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaSchool of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaSchool of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, ChinaMatrix-related pores play a significant role in controlling hydrocarbon production in organic-rich shales. Multiple matrix-related pore types of typical marine shales in the Sichuan Basin have been visually investigated and identified by transmission electron microscopy (TEM) on ultra-thin sections and by focused ion beam-scanning electron microscopy (FIBSEM) on polished sections. OM-hosted pores seem universal and range in sizes from below 1 nm to hundreds of nanometers and they are not homogeneously developed and distributed, which is mainly determined by thermal maturity and OM composition. Mineral-hosted pores are defined by mineral frameworks and occur in open spaces related to ductile or rigid grain fabric. The four porous mineral types that occur are clay intrapores, carbonate solvopores, pyrite interpores, and quartz interpores, and they range in size from less than 1 nm to more than several microns. Aggregate-hosted pores are predominantly associated with clay-organic aggregates, pyrite-organic aggregates, clay-pyrite aggregates, and clay-organic-pyrite aggregates. The most common aggregate-hosted pore networks are defined by clay-organic aggregates, and the pores are largely developed between the clay and organic layers and may be the important adsorption spaces for methane. Fracture-related pores include microchannels and microfractures of various sizes and shapes and they could play a key role in providing hydrocarbon migration pathways. FIBSEM and TEM show direct evidence that OM-hosted pores and fracture-related pores contribute more to the effective pore network and the excellent reservoir quality, whereas poor reservoir quality may come from aggregate-hosted pores.https://www.mdpi.com/2079-4991/12/23/4135FIBSEMTEMmarine shalemicrostructureporemicrofracture |
| spellingShingle | Jinxuan Han Hongjian Zhu Yanjun Lu Su Yang Manping Yang Erxiu Shi Yu Qi Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM Nanomaterials FIBSEM TEM marine shale microstructure pore microfracture |
| title | Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM |
| title_full | Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM |
| title_fullStr | Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM |
| title_full_unstemmed | Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM |
| title_short | Microstructural Analysis of Organic-Rich Shales: Insights from an Electron Microscopic Study by Application of FIBSEM and TEM |
| title_sort | microstructural analysis of organic rich shales insights from an electron microscopic study by application of fibsem and tem |
| topic | FIBSEM TEM marine shale microstructure pore microfracture |
| url | https://www.mdpi.com/2079-4991/12/23/4135 |
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