Experimental research on transport of coalbed methane by NMRI technique

Tang, Jupeng; Pan, Yuxin; Li, Chengquan

doi:10.1117/12.839262

Cited by 5 publications

(4 citation statements)

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“…The experiments used briquette specimens. Following Tang (2006), the mass of coal powder was taken as 8.7 kg, giving a briquette density of 1.087 t/m 3 . To make the mechanical properties of the briquette specimens similar to those of raw coal, the molding pressure was set as 20 MPa.…”

Section: Experimental Parametersmentioning

confidence: 99%

Evolution characteristics of precursor information of coal and gas outburst in deep rock cross-cut coal uncovering

Tang

Xin

Sun

et al. 2022

Int J Coal Sci Technol

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As mines become deeper, the potential for coal and gas outbursts in deep rock cross-cut coal uncovering is enhanced. The outburst precursors are unclear, which restricts the effectiveness and reliability of warning systems. To reveal the evolution characteristics of coal and gas outburst precursor information in deep rock cross-cut coal uncovering, briquette specimens are constructed and experiments are conducted using a self-developed true triaxial outburst test system. Using acoustic emission monitoring technology, the dynamic failure of coal is monitored, and variations in the root mean square (RMS) of the acoustic emissions allow the effective cracking time and effective cracking gas pressure to be defined. These characteristics are obviously different in deep and shallow coal. The characteristic parameters of gas outburst exhibit stepwise variations at different depths. The RMS and cumulative RMS have stepped failure characteristics with respect to changes in gas pressure. The characteristic parameters of coal failure are negatively correlated with the average in-situ stress and effective stress, but positively correlated with the lateral pressure coefficient of in-situ stress and the critical gas pressure. The transition characteristics are highly sensitive in all cases. The critical depth between deep and shallow coal and gas outbursts is 1700 m. The expansion multiple of acoustic emission intensity from the microfracture stage to the sharp-fracture stage of coal is defined as the outburst risk index, N1. For depths of 1100–1700 m, N1 ≥ 7 denotes a higher risk of outburst, whereas at depths of 1700–2500 m, N1 ≥ 3 indicates enhanced risk.

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Section: Experimental Parametersmentioning

confidence: 99%

Evolution characteristics of precursor information of coal and gas outburst in deep rock cross-cut coal uncovering

Tang

Xin

Sun

et al. 2022

Int J Coal Sci Technol

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“…Coal Body. As adsorption and desorption can be approximately regarded as a reversible process [21], the coal desorption capacity and desorption deformation obtained in this paper are the coal adsorption capacity and adsorption expansion capacity, and the relationship curve between adsorption capacity and adsorption deformation capacity and pore pressure can be obtained. The influence of Figure 6 shows the relationship between adsorption capacity, adsorption deformation, and pore pressure.…”

Section: Influence Of Desorption Deformation On Permeability Ofmentioning

confidence: 99%

Coal Permeability Variation during the Heating Process considering Thermal Expansion and Desorption Shrinkage

Feng

Cai

et al. 2022

Adsorption Science & Technology

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In order to explore the influence of coal deformation caused by temperature and desorption on seepage characteristics in the process of heat injection mining of coalbed methane, the permeability test, thermal expansion, and constant temperature adsorption desorption of coal samples under different temperature and stress states were carried out using the high temperature multifunctional triaxial test system, and the influence of thermal expansion and desorption deformation effect on coal permeability in the process of temperature increase is studied. The results show that (1) with the increase of temperature, the sensitivity of coal thermal expansion deformation to temperature decreases gradually. The thermal expansion deformation makes the coal matrix expand, and the seepage channel is squeezed and the permeability decreases. (2) The effect of thermal expansion deformation is related to the porosity of coal. When the porosity of coal is high, the thermal expansion deformation reduces the permeability; on the contrary, the inward expansion of thermal expansion deformation is limited, and the effect on permeability is weakened. (3) The desorption of coal cause matrix shrinkage. The higher the desorption amount, the more obvious the shrinkage and the higher the permeability. Increasing temperature promotes desorption deformation of coal and increases permeability. (4) In the process of increasing temperature, the change of coal permeability is affected by thermal expansion deformation and desorption deformation. With the increase of temperature, when the influence of thermal expansion deformation on coal permeability is dominant, the permeability decreases gradually, and when desorption deformation is dominant on coal permeability, the permeability increases gradually. (5) With the increase of axial pressure, confining pressure, and pore pressure, the decrease of coal porosity is smaller. When the temperature increases, the temperature corresponding to the minimum permeability point is smaller. The research conclusion provides a basis for the technology of heat injection mining coalbed methane.

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“…Zhao et al [11] conducted a coal sample permeability test under three-dimensional stress and revealed the influence of three-dimensional stress and coal adsorption on the coal gas seepage law. Tang et al [12] obtained the relationship between permeability and effective stress by studying the desorption and migration laws of coal seam gas during the simulated gas drainage process. Research by Enever and Hennig [13] pointed out that the change in coal permeability has an exponential relationship with the change in in-situ stress.…”

Section: Introductionmentioning

confidence: 99%

Calculation and program realization of coal pillar setting parameters in Huainan mining area

Yang

2024

PLoS ONE

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Coal pillar retention plays a crucial role in ensuring safety and minimizing ground deformation in coal mining operations. However, accurately and efficiently determining the optimal size of protective pillars, reducing coal pillar pressure, and addressing challenges such as limited access to retention parameters, lengthy observation times, and high labor costs are challenges that must be addressed. In this paper, we presented a methodology using Huainan mine as a case study to address these challenges. The solution involves deriving the formula for coal pillar retention parameters based on the Three Regulations definition and requirements. The total least squares algorithm was integrated with surface observation station data and the MATLAB software platform to automate the coal pillar retention solution. Furthermore, a linear regression model of coal pillar retention-related parameters was established using the geological mining condition data. The proposed ELM neural network model was optimized using a genetic algorithm and combined with the linear regression model to establish a predictive model. The results demonstrated that the proposed machine learning algorithm attains the requisite level of accuracy for industrial production.

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Experimental research on transport of coalbed methane by NMRI technique

Cited by 5 publications

References 0 publications

Evolution characteristics of precursor information of coal and gas outburst in deep rock cross-cut coal uncovering

Evolution characteristics of precursor information of coal and gas outburst in deep rock cross-cut coal uncovering

Coal Permeability Variation during the Heating Process considering Thermal Expansion and Desorption Shrinkage

Calculation and program realization of coal pillar setting parameters in Huainan mining area

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