Adsorption-induced pore blocking and its mechanisms in nanoporous shale due to interactions with supercritical CO2

Huang, Xianfu; Zhao, Ya‐Pu; Wang, Xiaohe; Pan, Lisheng

doi:10.1016/j.petrol.2019.03.018

Cited by 39 publications

(24 citation statements)

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“…On the other hand, the huge pressure also increases the blocking effect. 67,68 The cause of this phenomenon can be explained by the schematic as shown in Figure 14a. With the increase of injection pressure, more and more molecules are clustered near the pore throat due to the stronger interaction compared to CH 4 .…”

Section: Interaction Energymentioning

confidence: 99%

Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms

et al. 2019

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Although the focus of shale gas recovery has shifted to CO 2 sequestration with enhanced gas recovery (CS-EGR) for overcoming the low recovery efficiency, the adsorption and recovery mechanism of methane (CH 4 ) and carbon dioxide (CO 2 ) considering the effect of pore structures remains to be revealed. In this work, we focus on the influence of pore structures on adsorption behaviors of CH 4 and CO 2 at different geological depths and recovery process in different pore structures with various injection gas pressures. The results demonstrate that the excess adsorption capacity of CH 4 and CO 2 is in the order of cylinder-shaped > bottleneck > wedge-shaped > slit-shaped. The adsorption capacities of both CH 4 and CO 2 increase initially with geological depth until reaching maximum and then decrease with the depth going deeper. As for competitive adsorption of CH 4 and CO 2 , the pore structures do not have much influence on the selectivity. However, the pore structures have significant impact on shale gas recovery, and the difficulty of CH 4 molecules being displaced in various pore structures is ordered as cylinder-shaped > bottleneck > slit-shaped > wedge-shaped pores, which is consistent with the system resistance. The displacement efficiency of CH 4 in cylinder-shaped pores is about 59%, much less than in other pore structures. The injection pressure has a negative effect on the speed of shale gas recovery and displacement efficiency of CH 4 for the reason that more molecules aggregate into clusters near the pore throat and the flow blocking effect become more obvious when the injection pressure increases. Based on this actuality, we proposed a probable reliable method for CS-EGR: lower injection pressure is initially set to improve recovery efficiency, and higher pressure is finally used to increase CO 2 sequestration amount.

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Section: Interaction Energymentioning

confidence: 99%

Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms

et al. 2019

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“…Finally, we give the conclusions and outlook regarding the transport simulations of shale gas in microporous/nanoporous shale for the future studies. Note that, limited by the knowledge of authors and the length of article, this Review mainly focuses on presenting the current progress about molecular and pore-scale transport simulations of shale gas; therefore, some other momentous issues, such as adsorption/desorption, − and phase behavior, , as well as macroscale flow in shale fractures, , are not the objective of this paper.…”

Section: Introductionmentioning

confidence: 99%

Transport of Shale Gas in Microporous/Nanoporous Media: Molecular to Pore-Scale Simulations

Fan

et al. 2020

Energy Fuels

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As the typical unconventional reservoir, shale gas is believed to be the most promising alternative for the conventional resources in future energy patterns, attracting more and more attention throughout the world. Generally, the majority of shale gas is trapped within the tight shale rock with ultralow porosity (<10%) and ultrasmall pore size (as less as several nanometers). Thus, the accurate understanding of gas transport characteristic and its underlying mechanism through these microporous/nanoporous media is critical for the effective exploitation of shale reservoir. In this context, we present a comprehensive review on the current advances of multiscale transport simulations of shale gas in microporous/nanoporous media from molecular to pore-scale. For the gas transport in shale nanopores using molecular dynamics (MD) simulations, the structure and force parameters of various nanopore models, including organic models (graphene, carbon nanotubes, and kerogen) and inorganic models (clays, carbonate, and quartz), and flow simulation strategies (such as nonequilibrium molecular dynamics (NEMD) and Grand Canonical Monte Carlo simulations) are systematically introduced and clarified. The significant MD simulation results about gas transport characteristic in shale nanopores then are elaborated respectively for different factors, including pore size, ambient pressure, nanopore type, atomistic roughness, and pore structure, as well as multicomponent. Besides, the two-phase transport characteristic of gas and water is also discussed, considering the ubiquity of water in shale formation. For the lattice Boltzmann method (LBM) and pore network model (PNM) approaches to conduct pore-scale simulations, we briefly review its origins, modifications, and applications for gas transport simulations in a microporous/nanoporous shale matrix. Particularly, the upscaling methods to incorporate MD simulation into LBM and PNM frameworks are emphatically expounded in the light of recent attempts of MD-based pore-scale simulations. It is hoped that this Review would be helpful for the readers to build a systematical overview on the transport characteristic of shale gas in microporous/nanoporous media and subsequently accelerate the development of the shale industry.

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“…The pore structure of shale and other tight petroleum reservoir rocks is a critical component of the petroleum system to understand in order to predict the generation, accumulation, and movement of oil and natural gas within these formations. , For thermally mature shale reservoirs within the dry-gas window, methane and the other light alkanes that comprise natural gas have been shown to primarily reside within organic matter pores, as opposed to mineral pores and natural fractures and voids, with radii less than 50 nm. − Hydraulic fracturing of horizontal laterals in shale reservoirs allows for the flow of hydrocarbon gases out of these pores and voids such that they can be captured at the wellhead. This technological advancement has resulted in large-scale exploitation of natural gas resources within the conterminous United States. − Additionally, while shale reservoirs have been considered seals for potential geologic carbon sequestration efforts due to their low permeabilities, , there is interest in these formations for storage of atmospheric carbon dioxide (CO 2 ) following petroleum extraction by hydraulic stimulation. − …”

Section: Introductionmentioning

confidence: 99%

Exploring Methane Behavior in Marcellus Shale Micropores via Contrast Matching Neutron Scattering

et al. 2020

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Petroleum in shale reservoirs is hosted in organic matter and mineral pores as well as in natural fractures and voids. For thermally mature plays, e.g., the Marcellus Shale, methane and other light alkane gases are thought to be primarily contained in organic matter pores with radii ≤50 nm. Thus, in order to understand natural gas occurrence, transport, storage, and recoverability within unconventional reservoirs at the dry-gas stage of thermal maturity, it is critical to characterize the associated organic matter porosity across length scales from 50 nm down to the angstrom level. We utilized wide Q-range neutron total scattering to characterize perdeuterated methane (CD4) adsorption at 60 °C up to the zero average contrast (ZAC) pressure (∼60 MPa) within two mineralogically different samples collected from the same producing interval from the Middle Devonian Marcellus Shale. The neutron scattering approach used here provides structural information from the interatomic regime up to a nominal pore radius of ∼12.5 nm and, by reaching the CD4 ZAC pressure (∼60 MPa), it is possible to examine the distribution of open versus closed pores within this pore size range in the samples. Our results indicate that ∼10% of the largest pores measured are closed to CD4 for a quartz-rich sample whereas up to 25% of pores with a nominal radius of ∼12.5 nm are inaccessible within a sample with an equivalent proportion of quartz, carbonate, and clay. As pore size decreases, accessibility also decreases; all pores with radii ∼0.5 nm are effectively closed to CD4 in both samples. Additionally, up to ∼4.5× more CD4 is adsorbed within the quartz-rich sample at 60 MPa and we see no evidence for densification of CD4 within the shale pores. These findings suggest that for shale samples within the dry-gas window, (i) nanometer-scale porosity is primarily located within organic matter, (ii) the amount of available nanoporosity can vary widely over meter scales, and (iii) mineralogy plays a secondary role in dictating methane behavior within these systems.

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Adsorption-induced pore blocking and its mechanisms in nanoporous shale due to interactions with supercritical CO2

Cited by 39 publications

References 50 publications

Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms

Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms

Transport of Shale Gas in Microporous/Nanoporous Media: Molecular to Pore-Scale Simulations

Exploring Methane Behavior in Marcellus Shale Micropores via Contrast Matching Neutron Scattering

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Adsorption-induced pore blocking and its mechanisms in nanoporous shale due to interactions with supercritical CO2

Cited by 39 publications

References 50 publications

Influence of Pore Structure on Shale Gas Recovery with CO2 Sequestration: Insight Into Molecular Mechanisms

Influence of Pore Structure on Shale Gas Recovery with CO2 Sequestration: Insight Into Molecular Mechanisms

Transport of Shale Gas in Microporous/Nanoporous Media: Molecular to Pore-Scale Simulations

Exploring Methane Behavior in Marcellus Shale Micropores via Contrast Matching Neutron Scattering

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Resources

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Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms

Influence of Pore Structure on Shale Gas Recovery with CO₂ Sequestration: Insight Into Molecular Mechanisms