Anisotropic permeability evolution of coal with effective stress variation and gas sorption: Model development and analysis

Wang, Kai; Zang, Jie; Wang, Gongda; Zhou, Aitao

doi:10.1016/j.coal.2014.05.006

Cited by 145 publications

(80 citation statements)

References 37 publications

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“…Based on the same coal structure assumption, permeability models considering the anisotropy of the coal seams and various boundary conditions were also established (Wang et al, 2014;Lu et al, 2016).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

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Dynamic diffusion-based multifield coupling model for gas drainage

Liu

Lin

Yang

et al. 2017

Journal of Natural Gas Science and Engineering

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Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

“…However, before the establishment of the permeability model, the structure and composition of coal mass should be clarified (Lu et al, 2016;Wang et al, 2014). Coal seam is a naturally fractured dual-porosity reservoir, which contains microporous matrix and fractures.…”

Section: Introductionmentioning

confidence: 99%

Dynamic diffusion-based multifield coupling model for gas drainage

Liu

Lin

Yang

et al. 2017

Journal of Natural Gas Science and Engineering

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“…The unsynchronized changes in effective stress between the matrix and the cleat can alter coal permeability by the matrix deformation narrowing/widening the cleat aperture. To resolve these issues, several researchers introduced a deformation coefficient into the matchstick model to evaluate the impact of adsorption-induced deformation on the cleat aperture [33][34][35][36]. Although these models can investigate the cleat-matrix interactions induced by matrix swelling, the effective stress-controlled matrix deformation on coal permeability has received little attention.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Cleat-Matrix on Coal Permeability from Experimental Observations and Numerical Analysis

et al. 2019

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Gas transport through porous coal contains gas laminar flow in the cleat network and gas adsorption/diffusion in the matrix block. Since permeable capacity of the cleat is greater than that of the matrix, change of the matrix pressure readily lags behind change in the cleat pressure. Such unsynchronized pressure changes can result in a complex compatible deformation of a cleat-matrix system, significantly affecting the coal permeability. In this paper, we investigated the cleat-matrix interaction on coal permeability by using a modified pressure pulse decay method integrated with numerical analysis. The experimental results indicate that the bulk volume of the coal sample rapidly expanded at the beginning of gas injection, and then the volume expansion rate of the coal sample slowed down as the downstream pressure of the coal sample gradually equilibrated with the upstream pressure. During this process, the coal permeability was observed to gradually decrease with time. Numerical analysis results indicate that gas transport from the cleat to the matrix can attenuate the differential pressure between the cleat and the matrix. A smaller ratio of initial matrix permeability to initial cleat permeability can prolong decay duration of the differential pressure inside the cleat-matrix system. Although the coal sample is subjected to a stress-controlled condition, the coal permeability response to gas diffusion is closer to the case using a constant volume boundary. The dynamic change of coal permeability is significantly affected by the cleat-matrix interaction, in cases where the short-term change is mainly attributable to the cleat network and the long-term change is controlled by matrix swelling/shrinkage.

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“…Gas disaster has gradually become the primary problem that restricts the safe production of coal mine. e most universal technique to control gas disaster is gas extraction, which has two kinds: extraction by roadway and boreholes [1][2][3]. In this paper, we focus on the boreholes drilled from ground.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Parameters Optimization for Goaf Gas Boreholes

Gao

Yang

et al. 2019

Advances in Civil Engineering

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In view of the ground drilling of the N2206 working face in Shanxi Wangzhuang Coal Mine, the gas concentration is low and the extraction effect is not good. Fluent computational fluid dynamics software was used to simulate the ground extraction drilling position of the N2206 working face in the goaf (the distance from the top of the coal seam and the distance from the return to the wind). The numerical simulation results show that when the final hole of the ground extraction hole in the goaf is 16 m from the roof of the coal seam and the distance from the return air is 45 m, the extraction effect is optimal. The average extraction gas volume is 9.78 m3/min, and the average extraction gas concentration is 43.95%, the best extraction effect is obtained. After optimizing the ground drilling position in the goaf and combining with the site implementation, the maximum gas scouring amount of the extraction is 12.59 m3/min, which is 3.42 m3/min higher than the original. The maximum gas concentration of extraction was 63.54%, which was 28.82% higher than the original. After optimization, the gas concentration of the extraction is more than 30%, and the extraction effect is very good. Field application results further validate the reliability of theoretical analysis and numerical simulation results.

show abstract

Anisotropic permeability evolution of coal with effective stress variation and gas sorption: Model development and analysis

Cited by 145 publications

References 37 publications

Dynamic diffusion-based multifield coupling model for gas drainage

Dynamic diffusion-based multifield coupling model for gas drainage

Interaction of Cleat-Matrix on Coal Permeability from Experimental Observations and Numerical Analysis

Numerical Simulation of Parameters Optimization for Goaf Gas Boreholes

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