Gas Migration around Large Diameter Borehole with the Protective Screen Pipe in Fractured Soft Coal Seam

Ren, Zhongjiu; Wang, Haifeng

doi:10.1021/acsomega.3c02126

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…Zhang 16 studied the synergistic management technology of gas and coal spontaneous combustion in stratified mining of thick coal seams. Ren 17 studied the effect of gas extraction from 300 mm large-diameter boreholes.…”

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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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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Multi-Field Coupling Models of Coal and Gas and Their Engineering Applications to CBM in Deep Seams: A Review

Ma,

Zhou,

Cheng

et al. 2024

Energies

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In the process of deep coal seam mining, the problem of coal–gas compound disasters is increasingly prominent, with the safe and efficient extraction of gas serving as the key to disaster reduction. A deep coal seam gas extraction project is a complex coupled system involving multiple physical fields, such as stress fields, gas flow fields, and energy. Constructing a systematic theoretical framework of multiphysics field coupling is crucial for improving the safety and efficiency of gas extraction. This paper examines all existing multiphysics field coupling theories. It then suggests a theoretical modeling framework that is based on three important scientific issues: the coal deformation law, the gas flow law, and the coal porosity and permeability spatiotemporal distribution law. We further analyze the application and development of the model in typical coal seam gas extraction engineering on this basis. Finally, this paper points out the shortcomings of the current research and looks forward to the future research directions for the coupled coal and gas multiphysics field model, aiming to provide a theoretical basis and guidance for the model’s construction and application in gas extraction engineering.

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Promoting Gas Extraction Technology with Screen Pipe for Long Borehole Protection in Soft Seam

Wang,

Chen

et al. 2024

Processes

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The inherent properties of soft coal seams and their mechanical environment make long boreholes susceptible to issues like collapse, deformation, and blockages. These problems shorten the service life of the boreholes and hinder extraction efficiency. This paper tackles these challenges by analyzing the deformation and damage patterns of long boreholes in soft coal seams. It examines the stress distribution and deformation characteristics around both protected and unprotected boreholes at different burial depths. Additionally, it recommends using screen pipe protection technology to improve gas extraction and mining operations, as demonstrated in Changping Coal Mine. The results show that screen pipe protection substantially improves the stress distribution and deformation stability of coal seam boreholes. The flow attenuation coefficients of two boreholes equipped with protection technology decreased by 48% and 61%. After 50 days of extraction from boreholes with a protection rate exceeding 90%, gas concentration remained above 50%, which is 2.59 times higher than that of unprotected boreholes. This technology effectively addresses the frequent accidents, poor extraction performance, and inefficiency of long boreholes in soft coal seams, ensuring the mine’s safe and efficient production.

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Gas Migration around Large Diameter Borehole with the Protective Screen Pipe in Fractured Soft Coal Seam

Cited by 3 publications

References 27 publications

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

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

Multi-Field Coupling Models of Coal and Gas and Their Engineering Applications to CBM in Deep Seams: A Review

Promoting Gas Extraction Technology with Screen Pipe for Long Borehole Protection in Soft Seam

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