Laboratory measurements of methane desorption on coal during acoustic stimulation

Jiang, Yongdong; Xiao, Song; Líu, Hao; Yuezhen, Cui

doi:10.1016/j.ijrmms.2015.04.019

Cited by 46 publications

(31 citation statements)

References 29 publications

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“…From the experiments, time-accumulative characteristics of the desorption amount curves and CT scans demonstrated that width (or length) expansion of coal cleats which improved overall permeability of coal samples can only be accomplished after certain stimulation time (Jiang et al, 2015;Xiao et al, 2013). Hence at the initial stimulating stage of the experiment, the ultrasonic wave propagation at the interfaces of a cleat model, or around its surrounding medium, is governed by the elastic wave equation.…”

Section: Numerical Methodology 21 Governing Equationsmentioning

confidence: 99%

“…Xiao et al (2013) studied CT scans of coal samples after ultrasonic wave processing and identified that both fractures' width and quantity increased, which enhanced the overall permeability of coal samples. The existing research concluded that within the range of ultrasonic attenuation, mechanical vibration is a major factor for permeability enhancement, but its mechanism of whether and how the acoustic stimulation works effectively is still poorly understood and difficult to figure out through the existing laboratory experiments (Xiao et al, 2013;Jiang et al, 2015), and thus numerical simulation based method is chosen as an alternative approach to studying it here.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Jiang

Xing

2016

Journal of Natural Gas Science and Engineering

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Mechanical vibration is a major effect generated by acoustic stimulation inside a coal sample for enhancing its permeability. The numerical simulation based on the staggered-grid finite differential method (FDM) is applied to simulate 3D wave propagation in a fractured coal. Two parameters, shear wave energy (SE) and variable width of cleat (DW), are introduced and implemented in the numerical model to explicitly visualise and evaluate the acoustic stimulation effects. The polarized wave induced wave dynamics in a coal sample with a cleat/fracture is numerically simulated and analysed. Especially, the energy trapping and dynamic variation of fracture width in coal for the cleat/fracture with three different filled media (i.e. air, water and weak mineral) are numerically analysed and compared with each other subjected to different incident wave angles, and the optimal stimulation parameters are obtained through such sensitivity analysis. Simulation results show that the coal property (i.e. cleat and its filled media) and incident wave angles are crucial for acoustic stimulation to produce physical damages around coal cleats and enhance the permeability of fractured coal samples.

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Section: Numerical Methodology 21 Governing Equationsmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Jiang

Xing

2016

Journal of Natural Gas Science and Engineering

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“…The existing research concluded that within the range of complete attenuation of acoustic energy, the mechanical vibration is a major factor for permeability enhancement. However, its mechanism of whether and how the acoustic stimulation works effectively is still poorly understood and difficult to figure out through the existing laboratory experiments (Xiao et al, 2013;Jiang et al, 2015), and thus numerical simulation based method is chosen as an alternative approach to studying it in this thesis.…”

Section: Backgroundsmentioning

confidence: 99%

“…Based on the experience of existing engineering applications, acoustic stimulation method has been further modified to increase the gas production amount by enhancing coal reservoirs' permeability. The most noticeable research results are conducted by Jiang et al (Jiang et al, 2015) In this research, the researchers obtained time variation curve of desorption amount under constant temperature, which could isolate the impact of mechanical vibration effect by eliminating the influence of thermal effect. Under acoustic stimulation effect desorption quantity of CSG is higher than of without the acoustic wave.…”

Section: Experiments Of Acoustic Stimulationmentioning

confidence: 99%

“…From the experiments, time-accumulative characteristics of the desorption amount curves and CT scans demonstrated that width (or length) expansion of coal cleats which improved overall permeability of coal samples can only be accomplished after certain stimulation time (Xiao et al, 2013;Jiang et al, 2015). Hence at the initial stimulating stage of the experiment, the ultrasonic wave propagation at the interfaces of a cleat model, or around its surrounding medium, is governed by the elastic wave equation.…”

Section: Governing Equations Of Elastic Wavementioning

confidence: 99%

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Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

Jiang¹

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Acoustic stimulation method has been recognized as one of the most effective methods for enhancing coal permeability and improving the production amount of gas. Laboratory data has proved that the geometrical parameters (width and length) of coal cleats, which are the crucial pathway for gas migration, could be highly increased by acoustic field stimulation. The main reason for this positive effect is that acoustic energy could induce the mechanical vibration effect around coal cleats. However, the basic mechanism of this effect is still poorly understood due to the limitation of experimental facilities; the progress and details about this effect cannot be directly observed. It is imperative to conduct proper numerical simulation for the technology to improve the understanding of mechanical vibration. And only based on the conclusion of simulation results, the engineering parameters for optimal stimulation effect could be found. This thesis addresses this key issue and demonstrates how exactly the mechanical vibration is induced and affect the original coal cleat system. This thesis focuses on conducting numerical simulation for acoustic wave induced mechanical vibration around the coal cleats. The primary contributions are summarized as follows:(1) The numerical simulation based on the staggered-grid finite differential method (FDM) is applied to simulate 3D wave propagation in a single coal cleat model. Two parameters, shear wave energy (SE) and variable width of cleat (DW), are introduced and implemented in the numerical model to explicitly evaluate the acoustic stimulation effects. The results indicate that these parameters could accurately represent the variations of acoustic energy and geometrical parameters of the coal cleat model.(2) The polarized wave induced wave dynamics in a coal sample with a single cleat model is numerically simulated and analyzed; the energy trapping and dynamic variation of fracture width in coal for the cleat model with three different filled media (i.e. air, water and weak mineral) are numerically analyzed and compared with each other subjected to different incident wave angles, and the optimal stimulation parameters are obtained through such sensitivity analysis. Simulation results show that the mechanical vibration is induced by the energy trapping effect; coal property (i.e. cleat and its filled media) and incident wave angles are crucial for acoustic stimulation to produce physical damages around coal cleats and enhance the permeability of fractured coal samples. II (3)The numerical simulation is further applied to simulate the viscoelastic wave propagation in 3D coal sample with a coal cleat system. Two kinds of coal cleat system model, orthogonal cleat sets (OCS) and T-junction cleat sets (TCS), are adopted to investigate the influence of coal cleats special structure for mechanical vibration. A stochastic model building process, which includes Monte Carlo method and von-Ká rmá n function, is proposed to better represent the structure of coal cleat system and hete...

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A Microwave Heating Technology for Coalbed Methane Recovery

Lan

Wang

Zhang

et al. 2021

Proceedings of the International Petroleum and Petrochemical Technology Conference 2020

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Laboratory measurements of methane desorption on coal during acoustic stimulation

Cited by 46 publications

References 29 publications

Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

A Microwave Heating Technology for Coalbed Methane Recovery

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