Investigation of the Ultrasonic Stimulation Performance on Permeability Enhancement in Coal Seam: Field Tests and In Situ Permeability Evaluation

Fei, Jinbiao; Liu, Peng; Wang, Longkang; Zhong, Fangxiang; Xie, Chenglong; Jiang, Yongdong; Li, Quangui; Li, Mingyang

doi:10.1155/2022/2368323

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…Jiang et al 17 found that the desorption rate of methane in coal was significantly accelerated when ultrasonic waves were propagated in the coal body. Furthermore, Fei et al 18 conducted an ultrasonic wave-based field application at the Shuanglong coal mine in Shaanxi, China, and showed that the average gas flowrate in a single hole increased from 20 to 106%; the coalbed permeability increased at least 2.36 times after ultrasonic stimulation. Based on experimental results and actual measurement data of mines, it is feasible that ultrasonic waves can promote CBM recovery by heat injection.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic-Assisted Coalbed Methane Recovery: A Coupled Acoustic–Thermal–Mechanical–Hydrological Model

Yang

Wang

et al. 2023

Energy Fuels

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Ultrasonic propagation in coal seams is accompanied by heat transfer, which has the potential to increase coal seam permeability, enhance coalbed methane (CBM) recovery, and prevent coal and gas outbursts. Therefore, it is important to analyze the effects of heat transfer by ultrasonic vibration on CBM recovery and evaluate the prospects of engineering applications of ultrasonic heating technology. In this study, the factors affecting heat transfer by ultrasonic vibration were analyzed theoretically; then, CBM recovery under the condition of ultrasonic heating was simulated by establishing a coupled acoustic–thermal–mechanical–hydrological model. The correctness of acoustic–thermal model was validated by matching simulated data with experimental data. And the accuracy of the gas flow model was verified by comparing the production data from CBM extraction boreholes with the simulated data. The research results were as follows: heat transfer by ultrasonic vibration was affected by frequency and sound pressure. When the ultrasonic frequency varied from 30 to 40 kHz and the sound pressure varied from 0.1 to 0.12 MPa, the lower the frequency, the higher the sound pressure, and the better the ultrasonic vibration heat transfer effect. In addition, the thermal expansion volumetric strain of the coal matrix caused by the ultrasonic heating of coal seams was weaker than the shrinkage volumetric strain of the coal matrix caused by gas desorption, improving the porosity and permeability of the coal seams. Furthermore, the gas drainage standard area increased by 20.8 m2 after 720 days of CBM recovery when replacing conventional CBM recovery with ultrasonic-assisted CBM recovery. With a production time of 720 days, the maximum production of CBM after ultrasonic excitation at a frequency of 40 kHz and a sound pressure of 0.10 MPa increases from 3744 to 9740 m3/day compared to conventional excitation. Our fully coupled acoustic–thermal–mechanical–hydrological model can improve current understandings of heat and mass transfer in thermal simulation of ultrasonic-enhanced CBM recovery.

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Section: Introductionmentioning

confidence: 99%