Gas seepage laws based on dual porosity and dual permeability: Numerical simulation and coalbed methane extraction practice

Xu, Chao; Qin, Liangliang; Wang, Kai; Sun, Haoshi; Cao, Mingyue

doi:10.1002/ese3.871

Cited by 13 publications

(2 citation statements)

References 34 publications

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“…Nowadays, underground accidents in coal mines are frequent, causing huge casualties and economic losses. The majority of these accidents are caused by fire-induced gas explosions, with the severity of death reaching more than nine people per fire accident, and the severity of death in all other accidents is less than that of fire accidents, so coal mines need to pay sufficient attention to fire [4][5][6]. In recent years, China's coal enterprises also generally pay attention to the prevention of coal mine fire accidents, and the construction of a major disaster prevention and protection system for China's coal enterprises has gone through five stages: passive prevention, traditional empirical prevention pre-prevention post-prevention, systematic prevention and protection, and systematic scientific management [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Coal Mine Fire Emergency Rescue Capability Assessment and Emergency Disposal Research

et al. 2023

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Nowadays, underground coal mine accidents occur frequently, causing huge casualties and economic losses, most of which are gas explosion accidents caused by fires. In order to improve the emergency rescue capability of coal mine fires and reduce the losses caused by coal mine fires, this article is dedicated to the assessment of coal mine fire rescue capability. Taking the fire emergency rescue system of Lugou mine as an example, based on the introduction of gray system theory and gray evaluation method, an evaluation model was established to assess the risk of the fire emergency rescue index system of Lugou mine. Four primary and 19 secondary indicators were delineated, and a hierarchical structure model of the fire emergency rescue capability of the Lugou mine was established by combining expert opinions, and the weights of indicators at all levels were calculated by using hierarchical analysis. We then used the gray system evaluation method and expert scoring to judge the safety level of various indicator factors in the index system. The evaluation results show that the risk level of the emergency rescue system of the Lugou mine fire is higher than the fourth level. The main risk indicator factors are firefighting equipment, decision-making command, emergency education and training, and fire accident alarm. In response to this evaluation result, corresponding control measures were formulated in four aspects: rescue organization guarantee, personnel guarantee, material guarantee, and information guarantee, which optimally improved the emergency rescue capability of the Lugou mine fire and reduced the loss caused by fire.

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Section: Introductionmentioning

confidence: 99%

Coal Mine Fire Emergency Rescue Capability Assessment and Emergency Disposal Research

et al. 2023

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“…Cheng et al [22] studied the law of gas transport in the overburden fracture zone under the influence of mining, and designed reasonable parameters for high-level directional long holes for high-pressure gas extraction in an extraction zone based on the test results. Xu et al [23] considered coal to be a double-porous elastic medium and studied the gas transport law based on the dual permeability of a matrix and a fracture, and achieved good simulation results in the field. 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.…”

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

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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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Quantitative evaluation of the sealing effect of penetrating gas drilling and in situ repairing technology for smooth holes

Hu,

Yan,

Yang

et al. 2024

Energy Science & Engineering

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In this study, a new method is proposed to quantitatively determine the extraction of boreholes under the effect of time. The main purpose of this method is to divide the gas drilling holes in the monitoring time into two stages: the early stage of extraction and the middle stage of extraction. The early stage of extraction uses the gas pressure difference to detect the gas tightness of the drilling holes and determine the type of gas leakage of the drilling holes. Moreover, the unqualified drilling holes are repaired immediately to ensure that all the drilling holes in the middle stage of the monitoring are the qualified holes at the early stage of the inspection. In the middle of extraction, the average attenuation rate of the fitting attenuation curve of pure gas extraction in the extraction borehole is calculated by monitoring, the growth rate of the linear fitting of the pure air leakage is calculated, and their ratios are used as the basis for judging the repair value of the gas leak borehole and the gas leak borehole. This quantitative evaluation method is used to monitor the extraction effect of four test holes in a field test conducted at Ping Coal Mine 10. The results indicate that, after adopting in situ downhole repair technology in the early stage of extraction, the average air leakage of Borehole No. 4, which failed due to air leakage in the borehole, decreased from 9.33 to 1.26 L/min (a reduction of 86.5%). Similarly, that of Borehole No. 3, which failed due to penetration of fissures in the surrounding rock, had an air leakage drop from 8.35 to 1.34 L/min (a reduction of 84.0%). These improvements demonstrate the remarkable effectiveness of the method. The quantitative evaluation method established in this study is not only simple to operate but also stable and reliable. Thus, it is feasible to be applied in the field, which provides important technical support for the improvement in gas extraction effect during coal mine safety production.

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Gas seepage laws based on dual porosity and dual permeability: Numerical simulation and coalbed methane extraction practice

Cited by 13 publications

References 34 publications

Coal Mine Fire Emergency Rescue Capability Assessment and Emergency Disposal Research

Coal Mine Fire Emergency Rescue Capability Assessment and Emergency Disposal Research

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

Quantitative evaluation of the sealing effect of penetrating gas drilling and in situ repairing technology for smooth holes

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