Coal and gas outburst prevention using new high water content cement slurry for injection into the coal seam

Zhou, Peiling; Zhang, Yinghua; Huang, Zhian; Gao, Yukun; Wang, Hui; Luo, Qi

doi:10.1016/j.ijmst.2017.05.003

Cited by 20 publications

(12 citation statements)

References 2 publications

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“…Gas production increased by 62.12%, and the number of presuction holes decreased by 45.66%. Zhou et al [9] reported the results of laboratory experiments using cement-based high-water content slurries with different water-cement ratios for coal injection. They found that as the water-cement ratio increased, the fluidity of the mud and its setting time increased.…”

Section: Introductionmentioning

confidence: 99%

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Research on the Coal Seam Permeability-Increasing Technology via High-Pressure Water Jet Reaming and Its Application

et al. 2021

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Aiming at the problem of coal and gas outburst prevention and control in serious outburst dangerous coal seam under complex geological conditions in Qidong Coal Mine, the water jet drilling and expanding integrated device was used to implement the measures that expand holes and increase permeability by high-pressure water at a 912 working face. The experimental results show that when the pump pressure is between 13 MPa and 15 MPa, the particle size of pulverized coal can be effectively reduced and the discharge of pulverized coal can be increased. The coal output of a single hole is 0.8~2.3 t/m, with an average of 1.1 m/t. The unreamed conventional borehole has a single-hole initial gas drainage rate of 50.74 m3/d and a single-hole cumulative gas drainage rate of 736.12 m3 within 30 days. The initial single-hole gas drainage volume of the reaming borehole is 178.74 m3/d, and the cumulative single-hole gas drainage volume in 30 days is 2227.57 m3. After reaming, the initial gas drainage scalar of a single hole increases 3.52 times of the original unreamed conventional drilling and the average cumulative gas drainage scalar of a single hole reaches 3.03 times of the original unreamed conventional drilling. This technology and equipment have a good promotion and application value in gas treatment of soft, low-permeable coal seams.

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Section: Introductionmentioning

confidence: 99%

“…Change trend graph of gas drainage concentration and cumulative gas drainage scalar over time for six unreamed conventional boreholes for 30 consecutive days. Contrast curve of the cumulative extraction scalar volume between a single-reamed borehole and a single-unreamed conventional borehole for 30 consecutive days 9. Geofluids…”

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confidence: 99%

Research on the Coal Seam Permeability-Increasing Technology via High-Pressure Water Jet Reaming and Its Application

et al. 2021

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“…Coal strength is the key factor in resisting outbursts and determines whether the coal will be destroyed under the in-situ stress and gas pressure. Currently, the main measures for improving coal strength are grouting reinforcement and the use of a metal framework, which have obtained some good results in preventing outburst in rock cross-cut coal uncovering 9,10 . However, significant limitations are associated with these measures, e.g., it is difficult for grouting material to diffuse in coal seams, and the range of reinforcement is limited 11 .…”

Section: Introductionmentioning

confidence: 99%

Freezing method for rock cross-cut coal uncovering I: Mechanical properties of a frozen coal seam for preventing outburst

Yue

Wang

et al. 2019

Sci Rep

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A comprehensive technology is proposed to realize fast and safe rock cross-cut coal uncovering (RCCCU) based on artificial freezing engineering method. This comprehensive technology includes four steps, namely, drilling a borehole, wetting the coal body by water injection, gas drainage and freezing the coal seam by liquid nitrogen injection. In this paper, the compressive strength, tensile strength and shear strength of frozen coal specimens are tested to obtain the mechanical parameters of the specimen. Then, for RCCCU under freezing temperatures, the outburst prevention effects are calculated and quantitatively analysed with regard to three aspects, namely, the enhancement of coal the mechanical properties, the reduction in the coefficient of outburst hazard (COH) in the distressed zone and the reduction in the interfacial elastic energy ratio (IEER) between the coal seam and the roof/floor. The results show that a considerable improvement in the mechanical properties of frozen coal and that the coal mechanical parameters, such as the compressive strength and the tensile strength, increase linearly with decreasing temperature. The coefficient of outburst hazard in the distressed zone decreases rapidly and drops from above 0.8 to below 0.3. The interfacial elastic energy ratio is greatly reduced from dozens of times of that of the roof/floor before freezing to several times of that of the roof/floor after freezing, which effectively weakens the sudden change of the elastic energy at the coal-rock interface.

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“…Coal seams in China are characterized by having a low permeability and a high gas content, which is an essential reason for the occurrence of coal and gas outbursts [1][2][3][4][5][6]. Permeability-enhancing measures must be taken and the gas content must be below the critical values specified by the related provisions before the mining of the coal seam that has an outburst risk [7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Seepage and Damage Evolution Characteristics of Gas-Bearing Coal under Different Cyclic Loading–Unloading Stress Paths

Zou

2018

Processes

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The mechanical properties and seepage characteristics of gas-bearing coal evolve with changes in the loading pattern, which could reveal the evolution of permeability in a protected coal seam and allow gas extraction engineering work to be designed by using the effect of mining multiple protective seams. Tests on gas seepage in raw coal under three paths (stepped-cyclic, stepped-increasing-cyclic, and crossed-cyclic loading and unloading) were carried out with a seepage tester under triaxial stress conditions. The permeability was subjected to the dual influence of stress and damage accumulation. After being subjected to stress unloading and loading, the permeability of coal samples gradually decreased and the permeability did not increase before the stress exceeded the yield stage of the coal samples. The mining-enhanced permeability of the coal samples in the loading stage showed a three-phase increase with the growth of stress and the number of cycles and exhibited an N-shaped increase under the stepped-cyclic loading while it linearly increased under the other two paths in the unloading stage. With the increase of peak stress and the accumulation of damage in coal samples, the sensitivity of the permeability of coal samples to stress gradually declined. The relationship between the damage variable and the number of cycles conformed to the Boltzmann function.

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Coal and gas outburst prevention using new high water content cement slurry for injection into the coal seam

Cited by 20 publications

References 2 publications

Research on the Coal Seam Permeability-Increasing Technology via High-Pressure Water Jet Reaming and Its Application

Research on the Coal Seam Permeability-Increasing Technology via High-Pressure Water Jet Reaming and Its Application

Freezing method for rock cross-cut coal uncovering I: Mechanical properties of a frozen coal seam for preventing outburst

Seepage and Damage Evolution Characteristics of Gas-Bearing Coal under Different Cyclic Loading–Unloading Stress Paths

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