Experimental study on the gas phase permeability of montmorillonite sediments in the presence of hydrates

Wu, Zhiying; Li, Yanghui; Sun, Xiaofeng; Li, Man; Jia, Ruidong

doi:10.1016/j.marpetgeo.2018.01.015

Cited by 57 publications

(23 citation statements)

References 36 publications

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“…Thus, the volume of hydrate formed in the core sample can be calculated by equation .

V_{h} = \frac{m_{h}}{ρ_{h}} = \frac{\frac{()(, m_{w 0} - V_{w} ρ_{w})}{18 \times 6} ()(, 16 + 18 \times 6)}{ρ_{h}}

where V h is the volume of methane hydrate, m h is the mass of methane hydrate, and ρ h is the density of methane hydrate, ρ h = 0.914 g/ml (Wu, Li, Sun, Li, et al, ). The volume of methane gas in the core sample can be calculated by equation .…”

Section: Methodsmentioning

confidence: 99%

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Hou

Zhao

et al. 2020

JGR Solid Earth

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The permeability of sediments is an important parameter that effects flow characteristics of the gas and water in the process of natural gas hydrates development. The distribution of gas hydrate is generally heterogeneous in porous media. It poses a great challenge to the permeability measurement of hydrate‐bearing sediments. To study the effect of heterogeneous distribution of methane hydrate on the permeability of porous media, methane hydrate formation in the sandstone and permeability measurement was carried out using a low‐field nuclear magnetic resonance (NMR) measurement system in situ conditions. The spatial distribution of methane hydrate in the core samples was determined by combining the T2 distribution with magnetic resonance imaging. The results show that the distribution of methane hydrate is heterogeneous in the core samples. The temporal and spatial variation of permeability happens in the process of hydrate dissociation. The heterogeneity of methane hydrate distribution severely affects the analysis of permeability change. Considering the heterogeneity of methane hydrate distribution, a new method was proposed to obtain the quantitative relationship between hydrate saturation and relative permeability based on magnetic resonance imaging and the equivalent seepage capacity method. The results show that the relative permeability models obtained by this method agree better with experimental results. The optimum coefficients of relative permeability models obtained by equivalent seepage capacity method change significantly in contrast with the direct fitting method. The variation of the optimum coefficient is up to 300% in this study. The model coefficients are related to the pore characteristic of hydrate‐free porous media.

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“…Thus, the volume of hydrate formed in the core sample can be calculated by equation .

V_{h} = \frac{m_{h}}{ρ_{h}} = \frac{\frac{()(, m_{w 0} - V_{w} ρ_{w})}{18 \times 6} ()(, 16 + 18 \times 6)}{ρ_{h}}

Section: Methodsmentioning

confidence: 99%

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Hou

Zhao

et al. 2020

JGR Solid Earth

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“…The first empirical relationships of gas permeability with hydrate saturation in sand appeared in the 1970s , and were then confirmed in similar experiments on water permeability. , The interest to the gas permeability of hydrate-bearing rocks rekindled in the 2000s in the context of possible gas production from hydrate-bearing reservoirs. Experimental studies since that time focused on samples with natural or laboratory-formed pore gas hydrates ,− and revealed that nonlinear permeability decreases with increasing contents of pore hydrates. On the other hand, the relative permeability of hydrate-bearing rocks was simulated theoretically, − but the correlation of modeling data with experiments is not reliable enough to provide universal relationships and equations.…”

Section: Introductionmentioning

confidence: 99%

Gas Permeability of Sandy Sediments: Effects of Phase Changes in Pore Ice and Gas Hydrates

2021

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The gas permeability of sandy porous sediments is studied in freezing/thawing and pore gas hydrate formation/dissociation experiments using a specially designed system. The permeability of sandy soil to gas is controlled by phase changes of the pore water components (water, ice, or gas hydrate) depending on temperature and pressure. The gas permeability of the sand samples decreases upon freezing and during the formation of pore gas hydrates but increases when pore gas hydrates dissociate upon pressure drop to below-equilibrium values. The magnitude of permeability decrease and increase varies as a function of the initial water–ice saturation and the pore space structure. Clay contents and mineralogy affect the behavior of gas permeability in frozen and thawed sand samples containing a clay component. The experimental results can have multiple uses: modeling and testing of economically feasible techniques for gas production from permafrost Arctic reservoirs, including hydrate-bearing sediments, or mapping of permeable zones for tracing methane emission in high latitudes.

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“…Natural gas hydrates (NGHs) are non-stoichiometry compounds with hydrogen-bonded water cages acting as host and gas molecules as guest [1][2][3]. The guest gas molecules involve methane, ethane, propane, and carbon dioxide, etc., among which methane attracts much attention due to its potential in energy source and gas storage [4][5][6]. There are three different clathrate structures of gas hydrates, namely two cubic structures s I and s II, and one hexagonal structure s H. The clathrate structure was found to be dependent upon the size of the guest molecule [7].…”

Section: Introductionmentioning

confidence: 99%

Metastable state of gas hydrate during decomposition: A novel phenomenon

Sun

Fan

Yang

et al. 2020

Chinese Journal of Chemical Engineering

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Natural gas hydrates are solid compounds with cage-like structures formed by gas and water. An intriguing phenomenon that gas hydrates can dissociate at a low rate below the ice freezing point has been viewed as the metastability of hydrate. The mechanisms of hydrate metastability have been widely studied, and many mechanisms were proposed involving the self-preservation effect, supercooled water-gas-hydrate metastable equilibrium, and supersaturated liquid-gas-hydrate system etc. The metastable state of hydrate could be of crucial significance in the kinetics of hydrate formation and decomposition, heat and mass transfer during gas production processes, and the application of hydrate-based technique involving desalination, energy storage and transportation, and gas separation and sequestration. Few researches have systematically considered this phenomenon, and its mechanism remains unclear. In this work, various mechanisms and hypothesis explaining the metastable state of gas hydrates were introduced and discussed. Further studies are still required to reveal the intrinsic nature of this metastable state of gas hydrate, and this work could give some implications on the existing theory and current status of relevant efforts.

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Experimental study on the gas phase permeability of montmorillonite sediments in the presence of hydrates

Cited by 57 publications

References 36 publications

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Gas Permeability of Sandy Sediments: Effects of Phase Changes in Pore Ice and Gas Hydrates

Metastable state of gas hydrate during decomposition: A novel phenomenon

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