Application of gas wettability alteration to improve methane drainage performance: A case study

Lin, Junxin; Li, Kewen; Shi, Xiaohong; Zhao, Lipeng; Linghu, Jianshe

doi:10.1016/j.ijmst.2021.04.002

Cited by 38 publications

(12 citation statements)

References 41 publications

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“…In particular, isothermal adsorption experiments can be used to characterize the adsorption characteristics of coal from a macroperspective . The simulation method, mainly based on molecular dynamics and quantum mechanics theory, is aimed at analyzing the adsorption mechanism of gas in coal and rock at the molecular level. , On the basis of the two main methods, scholars adopted other methods (e.g., the adsorption thermodynamics and adsorption layer thickness theories) and combined with a variety of experimental means (e.g., X-ray photoelectron spectroscopy, liquid nitrogen adsorption, scanning electron microscopy, and contact angle measurements) to explore the influence mechanisms of temperature, pressure, moisture, the degree of coal metamorphism, the coal structure, and other factors on the adsorption–desorption characteristics of coal. The diffusion characteristics of CH 4 in coal are mainly characterized by the diffusion coefficient.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Methane Adsorption and Diffusion and its Influencing Factors Based on the Fractal Structure of Coal-based Porous Media

Liu

Yang

et al. 2022

Energy Fuels

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The adsorption–diffusion process of methane (CH4) in coal seams directly affects the amount of extractable gas (i.e., the free gas content). To clarify the relationship between the CH4 multiscale migration process and complex pore structure characteristics, the adsorption and diffusion characteristics of coal samples with different metamorphic degrees were taken as the research object, subdivided the gas adsorption structure scale, and quantitatively characterized the adsorption capacity of coal under different adsorption modes. Then, combined with the fractal characteristics of the coal adsorption pore complex structure, the evolution law of methane nonsteady-state diffusion was introduced to calculate the effective diffusion coefficient of methane under the unsteady state, elucidated the mathematical quantitative relationship between diffusion characteristics and structure characteristics, and explored the influence mechanism of coal structural parameters on the methane diffusion law. The results verified that the specific surface area was the dominant factor in the case of monolayer adsorption, while the complexity of the microporous structure was the most important factor in the case of microporous filling. Based on the calculation results of the fractal capillary bundle diffusion model, it was found that the specific surface area indirectly affects the diffusion movement by affecting the gas adsorption process, thus playing a leading role in the influence of fractal diffusion capacity of methane in coal. Overall, our research results provide a theoretical reference for the efficient mining of coalbed methane and mine gas disaster prevention.

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Section: Introductionmentioning

confidence: 99%

Mechanism of Methane Adsorption and Diffusion and its Influencing Factors Based on the Fractal Structure of Coal-based Porous Media

Liu

Yang

et al. 2022

Energy Fuels

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“…In some soft outburst coal seams with low permeability in China, the coal seam has suffered from strong structural compression deformation due to the influence of multistage geological structure, and its primary structure has been damaged seriously, and the coal body strength and coal seam permeability are low [13][14][15][16][17]. Therefore, the dynamic disaster of coal and gas outburst in this kind of coal seam is very serious, and with the deepening of the mining gradient, the mining conditions of the soft outburst coal seam under high ground stress, high gas pressure, and low permeability will become more worse [18][19][20][21]. Coal and gas outburst dynamic disasters are also increasingly threatening mine safety production [22,23].…”

Section: Introductionmentioning

confidence: 99%

Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

et al. 2022

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The No. 21 coal seam in the Zhengzhou mining area is a soft, three-layer, low-permeability coal seam prone to outbursts. The three-layer structure includes the coal seam and the roof and floor layers, which exhibit high gas contents and poor permeability. The dynamic hazards caused by coal and gas outbursts are very serious. A new permeability-increasing fracturing technique that combines hydraulic perforation and hydraulic fracturing was developed specifically for the geologic conditions of the gas-bearing No. 21 coal seam. Numerical simulations were developed to study the influence of the technique on the stress distribution and permeability of the coal around the borehole. In addition, the extracted borehole gas concentrations and extraction amounts at multiple sites were investigated before and after using the technique. The study shows that the permeability-increasing fracturing technique destroys the concentrated stress coal pillars via the development of fractures between boreholes in exposed hydraulically perforated coal. The coal stress within the zone with an effective increase in permeability decreased by 30%. Furthermore, the permeability in this zone increased by three times, and the average extracted gas concentration increased by over six times. The gas pressure in the No. 21 coal seam decreased from 1.1 MPa to 0.4 MPa, and the gas content decreased from 15.96 m3/t to 5.6 m3/t. All outburst prediction indexes measured on site did not exceed their respective limits. The technique not only effectively eliminated the dynamic hazards caused by coal and gas outbursts but also achieved efficient gas extraction in the Zhengzhou mining area.

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“…Gas is one of the main sources of mine disasters, which has become a key factor restricting the safe production of mines [11]. Gas control is the premise and foundation for safe and efficient mining in high-gas mining areas [12][13][14][15]. In the process of gas prevention, hydraulic fracturing technology is often used to increase the permeability of coal seam to improve the efficiency of gas extraction.…”

Section: Introductionmentioning

confidence: 99%

Mining Stress Distribution and Gas Drainage Application of Coal Seam Group under Fault Influence

et al. 2022

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The existence of fault structures often seriously endangers the safe production of coal mines. In order to ensure the safe and efficient production of close coal seam group mines under the influence of faults, it is of wide engineering significance to study the gas occurrence and extraction technology between coal seam groups under the influence of faults. In this study, the mining and gas drainage of 13817 working face in Yueliangtian Mine were taken as the research background. Combined with theoretical research, laboratory analysis, and numerical simulation analysis, the pressure relief range of coal seam and the evolution characteristics of surrounding rock stress were studied, the coal and gas comining system under the influence of faults was determined, the gas drainage technology was optimized, and the effect was investigated and analyzed. The results show that the gas pressure reduction zone is formed in the range of 20 m and 6 m of the lower wall of F1 fault, and the pressure relief effect is good in the range of 40 m above the roof of the working face to 20 m below the bottom plate during the advancing process. The optimized gas drainage technology has a good effect on gas control in coal seam group mining under the influence of faults. The absolute gas emission of the working face is reduced to 28~36 m3/min, the gas concentration in the upper corner of the mining face is about 0.6%, and the gas concentration of the return airflow is reduced to less than 0.5%. The gas extraction rate of No. 8 coal seam is 52.9%, and the gas content in the fault zone is reduced by 60%, realizing the safe and efficient comining of coal and gas. The research results have certain reference and application value for mine gas control with similar mining conditions.

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Application of gas wettability alteration to improve methane drainage performance: A case study

Cited by 38 publications

References 41 publications

Mechanism of Methane Adsorption and Diffusion and its Influencing Factors Based on the Fractal Structure of Coal-based Porous Media

Mechanism of Methane Adsorption and Diffusion and its Influencing Factors Based on the Fractal Structure of Coal-based Porous Media

Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

Mining Stress Distribution and Gas Drainage Application of Coal Seam Group under Fault Influence

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