Correlative X-ray and Electron Microscopy for Multi-scale Characterization of Heterogeneous Shale Reservoir Pore Systems

Goral, Jan; Mišković, Ilija; Gelb, Jeff; Marsh, Mike

doi:10.1306/13592018m1123694

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…High-resolution imaging techniques such as SEM and FIB-SEM provide insights into variations at the lamina and pore scales. Studying pore types is crucial for understanding pore network connectivity (permeability) and wettability, which control oil and water distribution and movement through pore spaces. − Various pore types associated with different minerals and organic matter have been identified in mudrocks. ,,− Loucks et al classified these into three general pore classes: interparticle pores (interP), intraparticle (intraP) pores within mineral crystals, and intraP organic matter (OM) pores. The formation of pores within the organic material of shales is intricately tied to their capacity to generate hydrocarbons, with this relationship influenced by the specific type of kerogen present in the rock and the thermal maturation of the organic material. ,, Moreover, Loucks et al found that OM pores in mudrocks develop when thermal maturation reaches an R o level of around 0.6% or higher, marking the onset of peak oil generation as per Dow and Kerogen .…”

Section: Introductionmentioning

confidence: 99%

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Ruse,

Hume,

Mokhtari

et al. 2024

Energy Fuels

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This study utilizes a combination of 2D high-resolution microscopy images and 3D reconstructions to shed light on pore connectivity and the distribution of organic matter within three different lithotypes encountered in a well situated within the productive core area of the Tuscaloosa Marine Shale play. It distinguishes unique fabric patterns among a silt-rich mudstone, a calcite-rich mudstone, and a clayrich mudstone. The spatial distribution of minerals and organic materials within these three types of mudstones significantly impacts the properties of the pore network, revealing that interparticle porosity plays a pivotal role in sustaining oil flow, while the presence of kerogen can impede pore communication. The calcite-rich mudstone exhibits the highest organic material content at 5.30 vol %, with most of its pores filled with ductile kerogen. In addition, as organic matter matures toward the base of the shale formation, it gives rise to a sponge-like structure characterized by the presence of nanometer-sized pores. In contrast, the silt-rich mudstone sample features pores exceeding 100 nm in size and boasts a porosity of 3.43 vol %, while an increase in clay content within the other two mudstone samples results in a sheet-like pore structure with smaller pores. The analysis reveals two distinct pore populations, with the group exhibiting pore radii smaller than 20 nm being the predominant statistic. When examining pore connectivity in the z-direction, it becomes evident that oil flow within the Tuscaloosa Marine Shale relies on isolated submicrometer-sized pore clusters. However, for hydrocarbons to flow effectively into the wellbore, these clusters would need to establish connectivity with the matrix pore network. This study is significant as it is the first to explore the relationship between pore structures and organic matter networks across various lithotypes in the Tuscaloosa Marine Shale, utilizing 3D FIB-SEM characterization.

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Section: Introductionmentioning

confidence: 99%

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Ruse,

Hume,

Mokhtari

et al. 2024

Energy Fuels

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“…Porosity and permeability of shales are often determined by examining core rock samples recovered from oil/gas wells drilled deep into rock formation. Recently, modern 2D/3D imaging techniques, have been used to investigate mineralogy and porosity in very fine detail, down to the sub-nanometer level [1][2][3][4] . These methods (and advanced image analysis) have facilitated characterization of the pore morphology within both the organic matter and non-organic (mineral) matrix of shales [5][6][7][8][9][10][11][12][13][14] .…”

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confidence: 99%

Confinement Effect on Porosity and Permeability of Shales

Goral

Panja

Deo

et al. 2020

Sci Rep

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Porosity and permeability are the key factors in assessing the hydrocarbon productivity of unconventional (shale) reservoirs, which are complex in nature due to their heterogeneous mineralogy and poorly connected nano-and micro-pore systems. Experimental efforts to measure these petrophysical properties posse many limitations, because they often take weeks to complete and are difficult to reproduce. Alternatively, numerical simulations can be conducted in digital rock 3D models reconstructed from image datasets acquired via e.g., nanoscale-resolution focused ion beam-scanning electron microscopy (FIB-SEM) nano-tomography. In this study, impact of reservoir confinement (stress) on porosity and permeability of shales was investigated using two digital rock 3D models, which represented nanoporous organic/mineral microstructure of the Marcellus Shale. Five stress scenarios were simulated for different depths (2,000-6,000 feet) within the production interval of a typical oil/gas reservoir within the Marcellus Shale play. Porosity and permeability of the pre-and post-compression digital rock 3D models were calculated and compared. A minimal effect of stress on porosity and permeability was observed in both 3D models. These results have direct implications in determining the oil-/gas-in-place and assessing the production potential of a shale reservoir under various stress conditions.

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Petrographic Imaging Methods for Characterizing Mudstone Reservoirs

Olson¹,

Milliken

2021

Encyclopedia of Petroleum Geoscience

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Correlative X-ray and Electron Microscopy for Multi-scale Characterization of Heterogeneous Shale Reservoir Pore Systems

Cited by 5 publications

References 19 publications

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Confinement Effect on Porosity and Permeability of Shales

Petrographic Imaging Methods for Characterizing Mudstone Reservoirs

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