Closed porosity in fossil coals

Alexeev, Anatoly; Vasilenko, T. A.; Ulyanova, E.V.

doi:10.1016/s0016-2361(98)00198-7

Cited by 72 publications

(26 citation statements)

References 3 publications

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“…Pores are the major reservoir sites of coalbed methane (CBM) and are considered to be important channels of CBM output (Liu et al, 2014a(Liu et al, , 2015bSang et al, 2009;Weishauptova et al, 2004). The development degree of pores and pore connectivity in coal determine the coal porosity and permeability (Alexeev et al, 1999;Liu et al, 2014aLiu et al, , 2015bSang et al, 2009;Weishauptova et al, 2004). The growth characteristics of pores, such as geneses, types, structures, sizes, and fractal features can affact gas content, gas migration, contact angle of fluid, and further the CBM exploitation (Alexeev et al, 2007;Alexeev et al, 2004;Crosdale et al, 1998;Gürdal and Yalçın, 2001;Liu et al, 2015b;Moore, 2012;Weishauptova et al, 2004;Yao et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

Liu¹,

Sang

Wang

et al. 2017

Journal of Petroleum Science and Engineering

146

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Pores in coal and their connectivity are important properties of coal, providing network or channels for gas storage and migration within coal, e.g. during the coalbed methane (CBM) recovery. To investigate the growth characteristics and genetic types of pores in coal in terms of macropore and mesopore, the pores of a high-rank coal were measured by various techniques such as the mercury intrusion method, nitrogen adsorption, focused ion beam scanning electron microscopy (FIB-SEM), and X-ray micro-CT (Computed Tomography). Two high-rank coals formed from regional metamorphism collected from the southern Qinshui basin were selected. The FIB-SEM and X-ray micro-CT provides detailed experimental information for development of a three dimensional (3D) pore network model, which was further used to characterize the pore connectivity. Volume percent of pores of these high-rank coals are dominated by mesopores of approximately 10-50 nm in width, and then followed by micropores, along with the smallest volume percent of macropores. The connectivity within this high-rank coal was mesopore-dominated pore network. Electron microscopy observations further revealed there are coalification-related pores and mineral-related pores in the high-rank coal. The coalification-related pores can be classified as secondary gas pores in organic matter and shrinkage-induced pores around quartz and clay minerals; and the mineral-related pores are developed within minerals, and can be classified as dissolution-created pores and intercrystalline pores. The secondary gas pores are macropores and have poor connectivity. The mineral-related pores can be both macropores and mesopores, and have little influence on pore connectivity due to small content of carbonate minerals in these samples. Under electron microscopy, the shrinkage-induced pores are mainly mesopores. The regional metamorphism, with a high abnormal old thermal field in the research area, is the precondition of the formation of the shrinkage-induced pores. The quartz and clay minerals in the coal provide different formation conditions and hence form different shapes of the shrinkage-induced pores. The coal samples include a large number of shrinkage-induced pores that act as the interconnected pores in the coal and exhibit good connectivity. The quartz and clay minerals play a significant role in developing the interconnected pores in the high-rank coal formed from regional metamorphism.

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Section: Introductionmentioning

confidence: 99%

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

Liu¹,

Sang

Wang

et al. 2017

Journal of Petroleum Science and Engineering

146

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“…The macropore system contains mutually perpendicular cleats, including a face cleat and butt cleat (Alexeev et al, 1999;Rice, 1993). Fig.…”

Section: Physical Structure Of Coal Fracturesmentioning

confidence: 99%

Effect of adsorption-induced matrix deformation on coalbed methane transport analyzed using fractal theory

Zhou

Yang

et al. 2015

Journal of Natural Gas Science and Engineering

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“…The molecular structure leads to a porous material with a wide range of pore sizes, that includes many microscopic pores resulting in a large internal surface area (Pashin 2008). The range of pore sizes and their interconnectedness influence mechanical properties, gas storage and flow and have been of interest to researchers in coal science for many years (Alexeev et al 1999, Hall et al 2000.…”

Section: Molecular and Porous Structure Of Coalmentioning

confidence: 99%

Mechanical and flow behaviours and their interactions in coalbed geosequestration of CO₂

Masoudian

Airey

El-Zein

2013

Geomechanics and Geoengineering

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Studying gas transport mechanisms in coal seams is crucial in determining the suitability of coal formations for geosequestration and/or CO 2-enhanced coal bed methane recovery (ECBM), estimating CO 2 storage capacity and recoverable volume of methane, and predicting the long-term integrity of CO 2 storage and possible leakages. Due to the dual porosity nature of coal, CO 2 transport is a combination of viscous flow and Fickian diffusion. Moreover, CO 2 is adsorbed by the coal which leads to coal swelling which can change the porous structure of coal and consequently affects the gas flow properties of coal, i.e. its permeability. In addition, during CO 2 permeation, the coal seam undergoes a change in effective stress due to the pore pressure alteration and this can also change the permeability of the coal seam. In addition, depending on the in situ conditions of the coal seam and the plan of the injection scheme, carbon dioxide can be in a supercritical condition which increases the complexity of the problem. We provide an overview of the recent studies on porous structure of coal, CO 2 adsorption onto coal, mechanisms of CO 2 transport in coalbeds and their measurement, and hydro-mechanical response of coal to CO 2 injection and identify opportunities for future research.

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Closed porosity in fossil coals

Cited by 72 publications

References 3 publications

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

Effect of adsorption-induced matrix deformation on coalbed methane transport analyzed using fractal theory

Mechanical and flow behaviours and their interactions in coalbed geosequestration of CO₂

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Closed porosity in fossil coals

Cited by 72 publications

References 3 publications

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

FIB-SEM and X-ray CT characterization of interconnected pores in high-rank coal formed from regional metamorphism

Effect of adsorption-induced matrix deformation on coalbed methane transport analyzed using fractal theory

Mechanical and flow behaviours and their interactions in coalbed geosequestration of CO2

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Product

Resources

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Mechanical and flow behaviours and their interactions in coalbed geosequestration of CO₂