Mechanism of a novel ultrasonic promoting fracturing technology in stimulating permeability and gas extraction

Zuo, Shaojie; Wang, Changwei; Yin, Lin; Peng, Shouqing; Ma, Ze; Zhang, Liang

doi:10.1016/j.egyr.2022.09.132

Cited by 8 publications

(3 citation statements)

References 40 publications

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“…After being treated with the clean fracturing fluid (C3), a small number of tiny pores were produced on the coal surface, as marked in Figure . This is because the fracturing fluid reacts with minerals, and the specific possible chemical reaction equations are eqs –. , Due to the weak acidity of the clean fracturing fluid, the pores produced are small in number and size, mostly smaller than 1 μm. The acidic fracturing fluid is more acidic, more pores will be produced on the coal sample surface (C4) after the action, and the pore size is relatively large.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, we can use P = 400 psi as the cut-off point to carry out piecewise fitting, as shown in Figure . At the same time, it can be found that when the pressure is greater than 400 psi, the fractal dimension obtained by calculation is greater than 3, so the fractal dimension of this stage is not considered . Effective fractal dimension calculation results are shown in Table .…”

Section: Resultsmentioning

confidence: 99%

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Evolution Characteristics of the Microstructure with Different Fracturing Fluids: An Experimental Study of Guizhou Bituminous Coal

Li,

Sun,

et al. 2023

ACS Omega

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Fracturing fluid is a key factor affecting the hydraulic fracture morphology and coal microstructure, which plays a key role in the hydraulic fracturing effect. To compare the effect of clean water, clean fracturing fluid, and acid fracturing fluid on the pore structure of coal, this paper used high-pressure mercury injection (MIP), low-temperature N2 adsorption (LT-N2A), and scanning electron microscopy (SEM) to determine the pore structure of Guizhou bituminous coal before and after the action of fracturing fluid. The results show that clean water can cause mineral expansion and reduce pore volume by about 6% and clean fracturing fluid and acid fracturing fluid can increase pore volume by 3 and 12%, respectively, due to different degrees of acidity. The MIP data show that the pore structure of coal samples is more complex after the action of different fracturing fluids, and acidic fracturing fluids can increase the fractal dimension of the pore by about 7%. The LT-N2A data showed that the fractal dimension of micropores and transition pores decreased after the action of different fracturing fluids. In general, acid fracturing fluid has the best effect on the coal microstructure, followed by clean fracturing fluid, and the least effect on clean water.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Evolution Characteristics of the Microstructure with Different Fracturing Fluids: An Experimental Study of Guizhou Bituminous Coal

Li,

Sun,

et al. 2023

ACS Omega

Self Cite

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show abstract

“…Most of the coal mines in China adopt underground mining, while gas disasters seriously restrict the safe production of mines. − Gas exists as an underground disaster, but it is a clean energy itself. If utilized efficiently, it can reduce the occurrence of underground gas disaster accidents and provide clean energy for human society. − Therefore, in the process of coal resources mining, gas drainage is often used as the main technical means to reduce the pressure and content of coal seam gas underground and to ensure the safe and efficient production of coal mines. − …”

Section: Introductionmentioning

confidence: 99%

Gas Evolution Principle during Gas Drainage from a Drill Hole along the Coal Seam and Reasonable Borehole Layout Spacing

Wang,

Zhao,

Wang

et al. 2023

ACS Omega

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The efficiency of coal seam gas drainage can be further improved by the accurate mastery of the gas evolution principle during gas drainage from the drill hole along the coal seam and reasonable optimization of borehole layout spacing. Based on the actual geological conditions of the no. 2 coal seam in a coal mine in Guizhou, China, and relevant control equations, a fluid–structure interaction model of gas drainage from a drill hole along the coal seam was established in this paper. Besides, numerical simulation research on the gas evolution principle during gas drainage along the coal seam and optimization of the borehole layout spacing was carried out with the COMSOL simulation software; and these were verified in combination with the project site. The results showed that in the early stage of gas drainage the gas pressure in the area near the drill holes decreased significantly. As the gas drainage went on, the degree of influence decreased gradually. During the gas drainage from adjacent drill holes, the gas pressure in the coal body between the holes decreased rapidly, and the migration was obvious. With the increase of the spacing between the drill holes, the drainage superposition effect between these holes gradually decreased until the influence area around a single hole is independently distributed in a circle-like shape, indicating that the optimization and the reasonable spacing of the drill holes are directly related to the effect of the gas drainage. With the increase of drilling spacing, the superposition effect of extraction between the holes gradually decreased until the influence area around a single hole is independently distributed in the shape of a circle, indicating that the optimization of drilling spacing is directly related to the effect of gas drainage. The results of numerical simulation were verified by analyzing the three-dimensional map of the gas pressure during the period of gas drainage at the project site and by comparing and examining the rational borehole layout spacing of the drill hole along the coal seam. The results of this study can be used to determine the spacing of gas extraction boreholes and improve the efficiency of gas extraction in the no. 2 coal seam of a coal mine in Guizhou, China, as well as to provide a reference for the gas pressure evolution, velocity field distribution, the prediction of effective drainage area, and the selection of rational borehole layout spacing during gas drainage.

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Impact of ultrasonic power on evolution mechanism of cavitation effect in water-bearing coal pores microstructure

Zhang,

Guo,

Deng

et al. 2024

Environ Earth Sci

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Mechanism of a novel ultrasonic promoting fracturing technology in stimulating permeability and gas extraction

Cited by 8 publications

References 40 publications

Evolution Characteristics of the Microstructure with Different Fracturing Fluids: An Experimental Study of Guizhou Bituminous Coal

Evolution Characteristics of the Microstructure with Different Fracturing Fluids: An Experimental Study of Guizhou Bituminous Coal

Gas Evolution Principle during Gas Drainage from a Drill Hole along the Coal Seam and Reasonable Borehole Layout Spacing

Impact of ultrasonic power on evolution mechanism of cavitation effect in water-bearing coal pores microstructure

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