Pore-network modeling of flow in shale nanopores: Network structure, flow principles, and computational algorithms

Cui, Ronghao; Hassanizadeh, S. Majid; Sun, Shuyu

doi:10.1016/j.earscirev.2022.104203

Cited by 45 publications

(15 citation statements)

References 357 publications

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“…The G value, which characterizes the geometry of the pore and pore throat cross sections, is calculated as follows: G = A P 2 where A is the cross-sectional area of the pores/throats in μm 2 and P is the perimeter of the pores/throats in μm. The geometry of the pores/throats will become more consistent with the increase in the shape factor. − The G value of a triangle depends on the size of its interior angle, and its value falls in the range from 0 to 0.0481. The G value of a rectangle is between 0.0481 and 0.071, and that of a circle is 0.0796 …”

Section: Resultsmentioning

confidence: 99%

Pore Structures and Evolution Model of Reservoirs in Different Secondary Structural Zones in the Eocene Shahejie Formation, Chezhen Sag, Bohai Bay Basin

Xiu,

Li,

et al. 2024

ACS Omega

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Although abundant unconventional oil resources have been discovered in conglomerate and sandstone reservoirs in rift basins, the mechanism of differential pore evolution in conglomerates and sandstone reservoirs within different secondary structural zones of rift basins is not yet clear. The pore structures of conglomerate and sandstone reservoirs in the distinct secondary structural zones in the Chezhen Sag were quantified in three dimensions using high-resolution microcomputed tomography (micro-CT). Thin section and scanning electron microscopy observations were used to investigate the differential evolution mechanisms of conglomerate and sandstone reservoirs. Micro-CT analysis of the pore structures of conglomerate and sandstone reservoirs revealed that sandstone reservoirs are superior to conglomerate reservoirs with regard to the pore number and pore connectivity and that sandstone reservoirs are more heterogeneous than conglomerate reservoirs. Triangles dominate the pore and pore throat geometries of sandstone and conglomerate reservoirs, while the sandstone reservoir pores are more regular than conglomerate reservoir pores. The depositional environment, mineral composition, and diagenetic intensity jointly control the quality of the reservoirs. Because of the lengthy transportation distance of their parent rocks, the compositional maturity and sorting behavior of sandstone reservoirs in depression and gentle slope zones are better than those of conglomerate reservoirs in steep slope zones, and thus sandstone reservoirs have a higher initial porosity than conglomerate reservoirs. The rapid compaction experienced by the conglomerate reservoirs in steep slope zones in their early stages creates a closed diagenetic environment, making it difficult to effectively improve reservoir porosity through dissolution. However, the widely developed microfractures in the reservoirs provide channels for fluid migration, promote the development of dissolution pores, and form a tight reservoir dominated by secondary pores. With weak compaction and an open diagenetic environment, the primary pores in sandstone reservoirs in the gentle slope zone are preserved in large quantities. Meanwhile, dissolution expands the secondary pores of the reservoir, resulting in a high-quality reservoir having both primary and secondary pores. In addition, an approach based on primary, secondary, and total porosity was proposed in the study to efficiently evaluate reservoir quality and identify reservoir evolution mechanisms.

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Section: Resultsmentioning

confidence: 99%

Pore Structures and Evolution Model of Reservoirs in Different Secondary Structural Zones in the Eocene Shahejie Formation, Chezhen Sag, Bohai Bay Basin

Xiu,

Li,

et al. 2024

ACS Omega

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“…Hydrocarbons in subsurface nanoporous media, such as shale, are promising energy resources to compensate for the shortage of conventional reservoirs. 1 Phase behavior in nanopores significantly impacts shale production; therefore, exploring hydrocarbon properties in nanopores is extremely important. From the molecular scale to the reservoir scale, the petrophysical properties of shale rock with nanopores differ considerably from those of traditional sandstone or carbonate reservoirs with micropores.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Hydrocarbons in subsurface nanoporous media, such as shale, are promising energy resources to compensate for the shortage of conventional reservoirs . Phase behavior in nanopores significantly impacts shale production; therefore, exploring hydrocarbon properties in nanopores is extremely important.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Compressibility Factor of Nanoconfined Alkanes along Vapor–Liquid Coexistence

Singh

2024

J. Chem. Eng. Data

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This study determines the effect of surface chemistry and the degree of nanoconfinement on the compressibility factors of methane, n-butane, and n-octane along vapor−liquid coexistence. This study also compares the bulk saturation compressibility factor of the selected alkane model to the corresponding experimental data. The saturated compressibility factors for the studied alkanes reasonably agree with the corresponding experimental data, with the maximum deviation shown by n-octane saturated vapor being less than 19%. The maximum change in the reduced compressibility factor of nanoconfined saturated liquid alkanes and saturated vapor alkanes to the corresponding bulk values is around 72 and 105%, respectively, for the studied slit pore in quasi-3D to quasi-2D regions. Interestingly, in ultrananopores (quasi-2D), the nanoconfined alkanes have shown an insignificant effect of the confining surface chemistry on the reduced compressibility factor of coexistence-saturated fluids. The critical compressibility factor of alkanes for the studied nanoconfinement has shown a nonmonotonic trend with the inverse of the nanopore width. Moreover, with a larger nanopore width, the critical compressibility factor approaches the corresponding bulk value.

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“…Yu et al 29 conducted a comprehensive review of shale gas transport simulations on the molecular and pore scales. Cui et al 30 elaborately introduced the porenetwork modeling fundamentals of shale. As shown in Table 1, there is still a lack of a multiscale overview of imbibition in shale oil reservoirs to visualize the current status and future trends.…”

Section: Introductionmentioning

confidence: 99%

Imbibition Mechanisms of Fracturing Fluid in Shale Oil Formation: A Review from the Multiscale Perspective

et al. 2023

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The breakthrough of shale oil in North America led to a worldwide energy revolution. Shale reservoirs show multiscale properties and a large proportion of nanopores compared to conventional reservoirs, which makes the imbibition mechanisms of fracturing fluids within shale reservoirs exceptionally complicated. For instance, the fracturing fluid shows a distinct imbibition behavior at different scales. Traditional models face significant challenges in imbibition characterization. Understanding the imbibition mechanisms in shale oil formations from a multiscale perspective can help to make full use of the positive effect and enhance oil recovery. We review imbibition mechanisms in shale reservoirs from the nanoscale to the reservoir scale. The imbibition principles in a single nanopore and the improvement of the traditional characterization models are clarified. Then, at the pore scale, we elaborate on the imbibition laws obtained from the microfluidic chip, pore network model, and direct simulations. We also outline the imbibition dynamics at the core scale, the influences of capillary forces and osmotic pressure, and the variations of the pore structure. Finally, the imbibition behavior at the reservoir scale and field examples considering the imbibition effect are introduced. We analyze the existing problems on each scale and discuss the future trends in this area. This work is expected to help readers systematically understand the mechanisms and behavior of fracturing fluid imbibition in shale oil reservoirs at different scales and accelerate the exploitation of shale resources.

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Pore-network modeling of flow in shale nanopores: Network structure, flow principles, and computational algorithms

Cited by 45 publications

References 357 publications

Pore Structures and Evolution Model of Reservoirs in Different Secondary Structural Zones in the Eocene Shahejie Formation, Chezhen Sag, Bohai Bay Basin

Pore Structures and Evolution Model of Reservoirs in Different Secondary Structural Zones in the Eocene Shahejie Formation, Chezhen Sag, Bohai Bay Basin

Estimation of the Compressibility Factor of Nanoconfined Alkanes along Vapor–Liquid Coexistence

Imbibition Mechanisms of Fracturing Fluid in Shale Oil Formation: A Review from the Multiscale Perspective

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