Pore space characteristics of the Upper Visean ‘Rudov Beds’: insights from broad ion beam scanning electron microscopy and organic geochemical investigations
Research output: Chapter in Book/Report/Conference proceeding › Chapter › Research
Authors
Organisational units
External Organisational units
- RWTH Aachen
- Microstructure and Pores GmbH
Abstract
This study gives valuable insights into the microstructure and pore space characteristics of 17 compositionally variable Visean shale samples from the Ukrainian Dniepr-Donets Basin (the ‘Rudov Beds’). The representative imaging area varies considerably (from 10 000 to >300 000 μm2) as a function of the mineralogy and diagenetic overprinting. The pores hosted in organic matter (OM) are restricted to secondary solid bitumen. Based on high-resolution maps from broad ion beam scanning electron microscopy combined with organic geochemical and bulk mineralogical data, we propose that the amount of OM-hosted porosity responds to the availability of pore space, enabling the accumulation of an early oil phase, which is then progressively transformed to a porous solid bitumen residue. The type of OM porosity (pendular/interface v. spongy) is reflected in the individual pore size distributions: The spongy pores are usually smaller (<50 nm) than the pendular or OM–mineral interface pores. The OM-hosted porosity coincides with differences in the composition of the extract, with high amounts of extractable OM and saturated/aromatic compound ratios indicative of abundant porous solid bitumen. The average circularity and aspect ratio of the mineral matrix pores correlate with the corresponding values for the OM-hosted pores, which show a preferred bedding-parallel orientation, suggesting that compaction influenced both types of pore.
Details
Original language | English |
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Title of host publication | Geological Society Special Publication |
Place of Publication | London |
Pages | 205-228 |
Number of pages | 24 |
Volume | 2020 |
Edition | 1 |
ISBN (electronic) | 2041-4927 |
DOIs | |
Publication status | Published - 2020 |
Publication series
Name | Geological Society Special Publication |
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Number | 1 |
Volume | 484 |
ISSN (Print) | 0305-8719 |