Differential Gas Drainage Technology for Upper Corner of Working Face by High Position Directional Long Borehole

Huijun, Duan; Hao, Shijun; Zhao, Yue

doi:10.1088/1755-1315/687/1/012180

Cited by 5 publications

(4 citation statements)

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“… 13 (2) When drilling hole drainage is implemented in the working face, the drilled hole is relatively shallow and located in the pressure relief zone of coal seam. 14 − 16 (3) The failure of borehole seal leads to low extraction efficiency.…”

Section: Introductionmentioning

confidence: 99%

Development and Application of Water Sealing Technology for Gas Drainage Boreholes

Hai-jin

Gao

et al. 2021

ACS Omega

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The poor sealing effect of gas extraction boreholes causes low efficiency of gas extraction. As a consequence, the requirements of coal mine safety production are often not attained. The sealing effect of boreholes depends not only on the sealing material itself but also on the combination degree between the material and the hole wall and the structural change characteristics of the material during operation. Our theoretical analysis shows that the amount of liquid leakage increases with the gap width Δ h in a cubic law, decreases with the sealing hole viscosity in a hyperbolic form, increases linearly with the diameter of the borehole, and increases with the eccentricity in a quadratic function. We have developed a PD sealing material that has good compactness and sealing effects, excellent water retention performance, and an expansion rate of 1.29. The material can generate secondary expansion through microscopic development, which is beneficial to improve the quality of the sealing hole. HV-CMC has good stability in plugging mucus. In addition, the manual pump has been redeveloped to be portable and also to overcome the blockage of the suction valve of the original device. In addition, the auxiliary device for drilling and sealing has been invented. The field application demonstrates that the gas concentration and flow pressure difference of the new sealing borehole can be maintained at a high level in a short period of time and then decrease slowly with time. The resulting improved sealing effect demonstrates that our new approach has important theoretical and practical significance for mine gas drainage.

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Section: Introductionmentioning

confidence: 99%

Development and Application of Water Sealing Technology for Gas Drainage Boreholes

Hai-jin

Gao

et al. 2021

ACS Omega

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“…Wang 12 analyzed the application of surface well gas drainage technology in a large dip coal seam mining area in Xinjiang, China. Zhang 13 and Huijun 14 Studied the effect of high-level borehole gas extraction technology on the management of gas in goaf area. In order to manage the gas in soft and hard composite coal seams, Li 15 researched that the construction of high-pressure water jet hydraulic flushing technology in the floor drainage roadway can improve the effect of gas extraction.…”

Section: Introductionmentioning

confidence: 99%

Study on the Application of Comprehensive Gas Control Technology for Source-Separated Three-Dimensional Gas Extraction in Large Mining Faces

Liu,

Wang,

Wang

et al. 2024

ACS Omega

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In order to address the challenges of high gas outburst in both the adjacent layers and the coal seam itself faced by large mining faces, a study on the three-dimensional extraction of gas from different sources at a large mining face was conducted.Based on the research on the instability and failure characteristics of the overlying strata during mining and the gas outburst characteristics at the large mining face, a source-separated threedimensional gas extraction system was established. A comprehensive gas management model for the large mining face, involving the extraction of gas from different sources, has been proposed. This model is suitable for gas management at large mining faces where there is a high gas emission in the adjacent layers and a complex structure of the coal seam. Through numerical simulations using FLAC 3D , the height of the "three zones" of the overlying strata and the range of the floor fracture zone at the large mining face were obtained, providing guidance for the layout of high-level drainage roadway, low-level drainage roadway, and floor drainage roadways. Following the coordinated layout of high-level drainage roadway, inclined high-level drainage roadway, and low-level drainage roadway, the reasonable optimization of gas extraction techniques in the coal seam, and the reasonable arrangement of floor rock predrainage roadways, the methane capture efficiency of the large 15115 mining face reached 87.5%. The methane concentrations at the upper corner and in the return airflow being below 0.8%. The methane concentration extracted from the coal seam boreholes is 2.9 times higher than that from the ordinary mining face after adopting "ordinary boreholes + large-diameter boreholes". This gas management model effectively addresses the gas-related challenges of the large mining face and improves the gas extraction rate, achieving harmonious mining and extraction of coal and methane.

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“…High-level borehole gas drainage is also the main gas control method in complex geological conditions. 13 Huijun et al 14 pointed out that the high-level directional deep-hole differential drainage method can effectively control gas emissions in the upper corner of a fully mechanized coal mining face in a thick coal seam. Liu et al 15 studied the influence of the fracture structure on the gas drainage rate under the condition of multifield coupling.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Space–Time Synergy of Coal and Gas Co-mining

et al. 2022

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The co-mining of coal and gas is the inevitable future direction of the mining of coal resources. Taking coal mining and gas extraction as the two subsystems of the coal and gas co-mining system, to reveal the mechanism of action between coal mining and gas extraction is the premise of orderly co-mining. On the basis of a similar simulation experiment of coal and gas co-mining, by obtaining the gas migration law during the mining process and collecting a large amount of data on the coal production and gas extraction, it is found that the two subsystems of coal extraction and gas extraction in the coal and gas co-mining system promote and restrict each other. The control parameters for coal mining and gas extraction that affect co-mining are identified. To coordinate the process connection between coal mining and gas extraction, the optimal synergistic relationship of co-mining should be found. The recovery rate and economic benefit of coal and gas resources are taken as the optimization objective function of coal and gas co-mining. Taking the safety production laws, regulations, and production technology-level restrictions of coal mining and gas drainage as constraints, by constituting a nonlinear model for the collaborative optimization of coal and gas co-mining, the method of determining the optimal advancing speed and optimal gas drainage volume of the working face is proposed. By optimizing variables, such as coal mining advancement, coal mining time, gas extraction time, and gas extraction volume, the co-mining of coal and gas is ensured to be safe and efficient, and the output of coal and gas resources is optimized. The time connection and the process succession of the two subsystems are attained. An overall orderly structure is formed between the coal mining system and the gas extraction system, and the mechanism of the cooperative co-mining of coal and gas is revealed. This research has important significance with regard to improving the basic theoretical system of coal and gas co-mining. The control variables of the co-mining working face in the Shaqu mine are optimized. After optimization, the profit is increased by 16.3%, and the gas extraction rate is increased by 2.6%. The drilling spacing is optimized according to the optimization results. The simulation shows that 7 m is the optimal drilling spacing of the working face.

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Differential Gas Drainage Technology for Upper Corner of Working Face by High Position Directional Long Borehole

Cited by 5 publications

References 0 publications

Development and Application of Water Sealing Technology for Gas Drainage Boreholes

Development and Application of Water Sealing Technology for Gas Drainage Boreholes

Study on the Application of Comprehensive Gas Control Technology for Source-Separated Three-Dimensional Gas Extraction in Large Mining Faces

Analysis of the Space–Time Synergy of Coal and Gas Co-mining

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