Multiple diffusion mechanisms of shale gas in nanoporous organic matter predicted by the local diffusivity lattice Boltzmann model

Yin, Ying; Qu, Zhiguo; Zhang, J.F.

doi:10.1016/j.ijheatmasstransfer.2019.118571

Cited by 35 publications

(43 citation statements)

References 46 publications

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“…(2) Currently, despite the fact that the multiscale simulations have been successfully conducted by coupling molecular and pore-scale simulations, the upscaling strategies of MD simulations are generally modifying the parameters of the boundary conditions − or flow equations (analytical models) − to consider the nanoscale effect into pore-scale simulations. Can the MD simulations be promoted to directly simulate pore-scale simulations, for example, by some coarse granulation methods or machine learning to save computational cost?…”

Section: Discussionmentioning

confidence: 99%

“…They claimed that the surface diffusion is the most important contributor for gas transport in organic matter, even for the entire shale matrix. A similar strategy was reported by Yin et al, − who triumphantly conducted the three-dimensional pore-scale investigations on a shale matrix with heterogeneity and anisotropy factors using a local diffusivity-modified LBM model.…”

Section: Pore-scale Simulationsmentioning

confidence: 94%

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

Fan

et al. 2020

Energy Fuels

125

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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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Section: Discussionmentioning

confidence: 99%

Section: Pore-scale Simulationsmentioning

confidence: 94%

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

Fan

et al. 2020

Energy Fuels

125

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“…Adsorbed gas and free gas in the organic matrix increase as the TOC content increases, while the amount of free gas in the inorganic matrix is not affected by the TOC content. In shale gas plays, adsorbed gas is a non-ignorable component in shale gas reserve calculation [27,39,[53][54][55], and gas ad-/desorption is important in the study of gas flow behaviors [56][57][58][59]. If we analyze the case further, we could ask how much adsorbed gas could be produced during shale gas production, and how significantly gas ad-/desorption affects gas transient flow behaviors in shale gas reservoirs.…”

Section: Adsorbed Gasmentioning

confidence: 99%

Review of Formation and Gas Characteristics in Shale Gas Reservoirs

et al. 2020

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An accurate understanding of formation and gas properties is crucial to the efficient development of shale gas resources. As one kind of unconventional energy, shale gas shows significant differences from conventional energy ones in terms of gas accumulation processes, pore structure characteristics, gas storage forms, physical parameters, and reservoir production modes. Traditional experimental techniques could not satisfy the need to capture the microscopic characteristics of pores and throats in shale plays. In this review, the uniqueness of shale gas reservoirs is elaborated from the perspective of: (1) geological and pore structural characteristics, (2) adsorption/desorption laws, and (3) differences in properties between the adsorbed gas and free gas. As to the first aspect, the mineral composition and organic geochemical characteristics of shale samples from the Longmaxi Formation, Sichuan Basin, China were measured and analyzed based on the experimental results. Principles of different methods to test pore size distribution in shale formations are introduced, after which the results of pore size distribution of samples from the Longmaxi shale are given. Based on the geological understanding of shale formations, three different types of shale gas and respective modeling methods are reviewed. Afterwards, the conventional adsorption models, Gibbs excess adsorption behaviors, and supercritical adsorption characteristics, as well as their applicability to engineering problems, are introduced. Finally, six methods of calculating virtual saturated vapor pressure, seven methods of giving adsorbed gas density, and 12 methods of calculating gas viscosity in different pressure and temperature conditions are collected and compared, with the recommended methods given after a comparison.

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“…Yao et al [17] studied the lifting gas leakage mechanism of damaged flexible composite materials and analyzed the influence of different types of damage on lifting gas leakage; this was of significance for the study of the damage-induced lifting gas leakage of envelope materials. The structure of an envelope material is different from that of carbon-fiber-reinforced composite laminates, and the mechanism of lifting gas diffusion caused by damage is different [18]. To study the lifting gas diffusion of an envelope material, it is necessary to establish a corresponding theoretical model according to its structural characteristics and use new experimental methods to obtain more accurate results.…”

Section: Introductionmentioning

confidence: 99%

Effect of Lifting Gas Diffusion on the Station-Keeping Performance of a Near-Space Aerostat

Ling

Lei

et al. 2022

Aerospace

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During the long-endurance flight of a near-space aerostat, the characteristics of lifting gas diffusion have a great influence on the flight altitude adjustment and station-keeping performance. Thus, in this study, a lifting gas diffusion model and a dynamic model that consider thermal effects, which had not been studied in similar models before, were developed. The dynamic model and thermal model were validated by historic flight data, and the calculated lifting gas diffusion results were compared with the experimental data of other researchers. The variations in the flight endurance, flight altitude, lifting gas diffusion rate, and diffusion coefficient of a near-space aerostat were analyzed. The effects of the ratio of porosity to tortuosity and envelope radiation properties on the mass of the lifting gas and flight altitude were considered in detail. To analyze the effect mechanism of the ratio of porosity to tortuosity and the envelope radiation properties, the envelope and gas temperature, as well as the gas pressure, were studied. The results show that the lifting gas diffusion rate and diffusion coefficient are very sensitive to the change in the ratio of porosity to tortuosity and envelope temperature. The results obtained from the analysis of the lifting gas diffusion can lay a solid foundation for improving the flight performance of near-space aerostats and for providing improved design considerations for aerostats.

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Multiple diffusion mechanisms of shale gas in nanoporous organic matter predicted by the local diffusivity lattice Boltzmann model

Cited by 35 publications

References 46 publications

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

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

Review of Formation and Gas Characteristics in Shale Gas Reservoirs

Effect of Lifting Gas Diffusion on the Station-Keeping Performance of a Near-Space Aerostat

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