Modification and enhancement of permeability of coal seam using mined CO2 foam fracturing fluid

Liu, Shuo; Wang, Junfeng; Wu, Jianming; Tang, Yibo

doi:10.1016/j.jngse.2018.09.028

Cited by 10 publications

(7 citation statements)

References 19 publications

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“…As shown in Figure , the complexity of the pore structure is reduced and the transport channels of CBM are improved under the pore-enlarged-transformed effects of LCPTF, conducive to reducing the capacity of capillary condensation of pores and enhancing the desorption ability of methane molecules. Other stimulation measures also achieved a similar result that the adsorption constant b increased, including HNO 3 and HF acid treatment, hydraulic slotting, and CO 2 foam fracturing . Therefore, the above analysis indicates that LCPTF has the enhanced effect on the desorption capacity of methane in coal.…”

Section: Resultsmentioning

confidence: 99%

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Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal

Liu

Zhang

et al. 2023

Energy Fuels

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Liquid CO2 phase transition fracturing (LCPTF) is a kind of novel waterless fracturing technology for enhancing the coalbed methane (CBM) recovery. Relevant current studies are focused on exploring the transformed effect of LCPTF on the nanopore structure in coal. However, its influence on gas adsorption capacity has been rarely reported. This study addresses coal induced with LCPTF. The structure alterations of mesopores (2–50 nm) and macropores (>50 nm) and their effects on the gas adsorption capacity are evaluated with comprehensive measurements of a mercury intrusion porosimetry, low-temperature N2 adsorption, and isothermal adsorption. The results indicate that LCPTF has an enlarged effect on macropores, resulting in an increase in pore size and volume and a reduction of the pore specific surface area. The pore-enlarged-transformed effects of LCPTF cause an increase in pore size and a reduction of the pore volume and pore specific surface area of mesopores. The variations of the pore structure after LCPTF cause a reduction of the adsorption constant a and the increase in the adsorption constant b, indicating LCPTF’s reductive effect on adsorption capacity as well as its enhanced effect on desorption capacity. A novel effect evaluation method of LCPTF for improving CBM recoverability is proposed based on the variations of gas saturation and critical desorption pressure. This study examines, from the perspective of adsorption and desorption, the mechanism of LCPTF for enhancing CBM recovery, which provides theoretical guidance for LCPTF’s technical improvement and optimization of field application so as to secure a more reliable and efficient CBM recovery.

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Section: Resultsmentioning

confidence: 99%

“…Other stimulation measures also achieved a similar result that the adsorption constant b increased, including HNO 3 and HF acid treatment, 36 hydraulic slotting, 52 and CO 2 foam fracturing. 62 Therefore, the above analysis indicates that LCPTF has the enhanced effect on the desorption capacity of methane in coal.…”

Section: Variation Of Adsorption Constantsmentioning

confidence: 88%

Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal

Liu

Zhang

et al. 2023

Energy Fuels

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“…This leads to the formation of more capillary voids between coal particles, ultimately resulting in changes in the water absorption of the particles. 31 4.2. Changes in Water Absorption.…”

Section: Xrd Measurement Resultsmentioning

confidence: 99%

“…The water absorption of coal particles can be reflected by their internal solution rise height. 31 For coal particles with different particle sizes, the wetting height (solution rise height) of coal particles was compared under the same solution and treatment conditions, and the larger the value of solution rise height, the stronger the water absorption of coal particles and the easier they are to be wetted. 33 From Figure 6, it is found that the absorbed coal particles in the tube appear black in color and the unabsorbed particles appear gray-black and the demarcation line between the two parts is obvious, so the height of absorption of the coal particles can be recorded by external photographs.…”

Section: Solution Rise Heightmentioning

confidence: 99%

Study on the Water Absorption Characteristics of Anthracite Particles after Immersion in Water

Jin,

Wang,

Duan

et al. 2024

ACS Omega

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“…In addition to hydraulic measures, scholars have also put forward many other advanced coal seam gas drainage technologies. Chen et al, 23 Liu et al, 24 and Wang et al 25 use the expansion of high-pressure gas after the phase change of liquid CO 2 to crack the coal body so as to increase the drainage amount of gas in the coal seam. In the laboratory, Tang et al 26 analyzed the feasibility of injecting CaO demolition materials into the borehole to enhance the permeability of coal seams.…”

Section: Introductionmentioning

confidence: 99%

New Technology of Mechanical Cavitation in a Coal Seam to Promote Gas Extraction

et al. 2022

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Realizing efficient gas drainage in low permeability coal seams has always been a difficult problem for coal miners. Based on this, this paper proposes a new technology of large-diameter mechanical cave-making to promote gas extraction in a coal seam. This technology mainly uses the pressure of a water injection pump to control the automatic opening and closing of a mechanical reaming device to realize mechanical cavitation, and the hole diameter can reach up to 500 mm. The gas drainage effect of mechanical cavitation drilling is analyzed by a numerical simulation, which shows that under the condition of the same drainage time, the larger the cavitation radius is, the larger the effective influence radius of gas drainage is. According to the field test results, the time of single cave-making is about 5 min, and the speed of cave-making is fast. The coal output of a single cave is 0.42 t/m, and the pressure relief effect is obvious. Compared with ordinary drilling, the gas drainage concentration of mechanical cavitation drilling is increased by 2 times and the net amount of drainage is increased by 1.8 times. Large-diameter mechanical cavitation technology can better improve the gas drainage effect of outburst coal seams with low permeability and has a good application prospect.

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Modification and enhancement of permeability of coal seam using mined CO2 foam fracturing fluid

Cited by 10 publications

References 19 publications

Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal

Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal

Study on the Water Absorption Characteristics of Anthracite Particles after Immersion in Water

New Technology of Mechanical Cavitation in a Coal Seam to Promote Gas Extraction

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Modification and enhancement of permeability of coal seam using mined CO2 foam fracturing fluid

Cited by 10 publications

References 19 publications

Effects of Liquid CO2 Phase Transition Fracturing on Methane Adsorption of Coal

Effects of Liquid CO2 Phase Transition Fracturing on Methane Adsorption of Coal

Study on the Water Absorption Characteristics of Anthracite Particles after Immersion in Water

New Technology of Mechanical Cavitation in a Coal Seam to Promote Gas Extraction

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Product

Resources

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Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal

Effects of Liquid CO₂ Phase Transition Fracturing on Methane Adsorption of Coal