Numerical Simulation of Effective Extraction Radius of Pre-Drainage Borehole Based on Coal Damage Model

Zhang, Dangyu; Zhang, Minbo; Zhang, Shilong; Wang, Zichao; Jin, Yan; Liu, Rentao

doi:10.3390/su15054446

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…Due to the specificity of China's energy structure, the demand for coal mines is increasing, and mining is accompanied by the risk of coal and gas protrusion [1]. Gas extraction is an effective measure with which to prevent such mine accident disasters and is the main means with which to manage and utilize gas in China [2,3]. At present, through a combination of field practice and numerical simulation, it is the main technical means with which to improve extraction efficiency and ensure stable gas extraction by mastering the law of coal seam gas transport and determining the effective extraction radius of boreholes [4,5], so as to provide a reference basis for a reasonable layout of drilling methods and spacing.…”

Section: Introductionmentioning

confidence: 99%

“…Zou et al [24] studied the effective extraction radius of gas with the use of COMSOL in order to improve the efficiency of gas extraction and determined the spacing of hole placement in practical engineering. Zhang et al [3] established a fully coupled model that considered coal damage deformation via dividing the permeability change stages by plastic damage extent, and studied the influence of different factors on the effective extraction radius to optimize the gas discharge design of a specific coal mine working face. Xu et al [25] proposed reasonable hole spacing and spacing based on the study of effective extraction radii to reduce the influence of the superimposed extraction effect of boreholes in the process of pre-pumping gas from coal seams, and improved the efficiency of gas extraction by establishing a coal seam gas-solid coupling model.…”

Section: Introductionmentioning

confidence: 99%

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Simulation Study on the Characteristics of Gas Extraction from Coal Seams Based on the Superposition Effect and Hole Placement Method

Jin

Zhang

et al. 2023

Sustainability

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In order to obtain a reasonable extraction drilling method for coal seam working faces and to carry out targeted as well as cost-effective hole placement optimization, a gas–solid coupled model based on the coal rock deformation field and the matrix–fissure dual seepage–diffusion field was established and numerically solved via the use of COMSOL Multiphysics finite element software to optimize the gas transport parameters of the Dongpang coal mine based on the study of the coal seam gas transport law. This study shows the following: With an increase in the extraction time, the gas content of the coal seam was reduced to a minimum. It shows that, with an increase in the extraction time, the gas pressure and seepage velocity keep decreasing the stable value, the main stress around the borehole redistributes, and the coal permeability keeps decreasing with an increase in the decay coefficient. The extraction radius of the boreholes increases exponentially with the extraction time, and the reasonable extraction hole size is 94 mm; the use of multiple boreholes for pre-drawing gas via the use of the interval between the effective extraction radius and the influence radius results in a blind extraction zone caused by the superposition effect between the boreholes, and the residual gas value of the coal seam increases with an increase in the borehole spacing. The use of an equilateral triangular hole layout can avoid the extraction blind zone, and the pre-sumping effect is good after field application, which ensures the safe production of coal mines as well as the reasonable use of resources.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation Study on the Characteristics of Gas Extraction from Coal Seams Based on the Superposition Effect and Hole Placement Method

Jin

Zhang

et al. 2023

Sustainability

Self Cite

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Study on the effective drainage range of long horizontal borehole for goaf gas drainage

Guo,

Yuan

et al. 2024

Energy Science & Engineering

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Laying long horizontal borehole (LHB) in mining‐induced strata fractures for coal‐bed gas drainage in the goaf is a pivotal method for eliminating safety hazards, preventing atmospheric pollution, and realizing gas utilization. A crucial premise of this method is to determine the effective drainage range of the borehole, a key parameter directly affecting boreholes spacing and drainage efficiency. In this study, a model of gas seepage during LHB drainage within a circular equipotential boundary was presented, and the complex variable function theory and the mirror principle were adopted for deriving the complex potential function of gas flow under the condition of LHB drainage and the drainage volume function of a single center borehole. Besides, the main indicator to determinate the effective drainage range of LHB was given. Specifically, the indicator refers to the distance between the turning point (the point at which the change rate of the gas flow velocity is −0.002 around the borehole) and the center of the borehole. Subsequently, numerical simulation was conducted to obtain the effective drainage range of LHB within mining‐induced fractures of overlying strata, that is, 4 m < r < 7 m. Furthermore, discussion of the effective drainage range of LHB was carried out by analyzing gas flow velocity distributions and LHB drainage volumes. A case study demonstrates that a double‐borehole layout with a 10 m spacing can effectively control pressure‐relief gas in the goaf. Meanwhile, such a layout can achieve well‐balanced drainage efficiency of each borehole with a minimal difference of 0.31 m3 min−1, which is only about 7.9% of the average drainage volume of the two boreholes. The above results verify that the determined effective drainage range of LHB is reasonable. The research results can provide references for determining the drainage range of LHB in multi‐borehole layout of coal mines, and then determining the spacing of LHBs arrangement, thereby improving the efficiency of gas extraction.

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Optimization Study and Validation of Gas Extraction Parameters Based on Heat-Fluid-Solid Coupling in Coal Seam

Zhang,

Yan,

Zhong

et al. 2023

Solid Fuel Chem.

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Numerical Simulation of Effective Extraction Radius of Pre-Drainage Borehole Based on Coal Damage Model

Cited by 3 publications

References 12 publications

Simulation Study on the Characteristics of Gas Extraction from Coal Seams Based on the Superposition Effect and Hole Placement Method

Simulation Study on the Characteristics of Gas Extraction from Coal Seams Based on the Superposition Effect and Hole Placement Method

Study on the effective drainage range of long horizontal borehole for goaf gas drainage

Optimization Study and Validation of Gas Extraction Parameters Based on Heat-Fluid-Solid Coupling in Coal Seam

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