Numerical investigation on the coupled gas-solid behavior of coal using an improved anisotropic permeability model

Yang, Diansen; Qi, Xianyin; Chen, Weizhong; Wang, Shugang; Dai, Feng

doi:10.1016/j.jngse.2016.06.058

Cited by 29 publications

(6 citation statements)

References 30 publications

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“…However, the difference between gas production of borehole I (i.e., QI) and gas production of borehole II (i.e., QII) increases gradually with the process of gas drainage, then QI and QII reach 1285.34 L and 1219.43 L, respectively. The different drainage effects between two branch boreholes are mainly because of the incompletely homogeneous coal [31]. Therefore, the total gas flow rate and gas production of boreholes are critical, as shown in Figure 5(b).…”

Section: Gas Drainage Effect With Stress Unloaded In Threementioning

confidence: 99%

Experimental Study on the Gas Flow Characteristics and Pressure Relief Gas Drainage Effect under Different Unloading Stress Paths

Zhang

Wang

et al. 2020

Geofluids

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Coal seam gas is a critical substance because it can be a source of a large quantity of clean energy as well as a dangerous source of risk. A pressure relief gas drainage is an effective and widely used method for coal seam gas recovery and gas disaster control in coal mines. A series of pressure relief gas drainage experiments were conducted using large-scale coal samples under different unloading stress paths in this study to explore the unloading stress paths. From the experimental results, the dynamic evolutions of gas pressure, coal temperature, and gas production were analyzed. The trends of gas pressure and coal temperature during pressure relief gas drainage were similar: dropping rapidly first and then slowly with time. Correspondingly, gas production was fast in the early stage of pressure relief gas drainage and became stable thereafter. Meanwhile, gas flow characteristics were significantly affected by the unloading stress paths. Gas pressure and coal temperature had the maximum descent by unloading stress in three directions simultaneously, and the unloading stress of the Z direction had the minimal impact when only unloading in one direction of stress. However, the influence of unloading stress paths on gas production was complex and time dependent. The difference coefficient parameter was proposed to characterize the influence degree of unloading stress paths on the pressure relief gas drainage effect. Eventually, the selection of unloading stress path under different situations was discussed based on time, which is expected to provide the basis for pressure relief gas drainage.

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Section: Gas Drainage Effect With Stress Unloaded In Threementioning

confidence: 99%

Experimental Study on the Gas Flow Characteristics and Pressure Relief Gas Drainage Effect under Different Unloading Stress Paths

Zhang

Wang

et al. 2020

Geofluids

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“…To analyze desorption laws of gas-bearing coal under different vibration conditions, the experimental data were fitted with different models, including the diffusion model, the empirical formula, the percolation model, and the desorption-diffusion model (Crosdale et al, 1998;Jiang et al, 2015Jiang et al, , 2008Yang et al, 2016). Figure 4 is the fitted curves of experiment No.…”

Section: Influence Of Vibration Frequencymentioning

confidence: 99%

Experimental research on desorption characteristics of gas-bearing coal subjected to mechanical vibration

Chen

Zhang

Shen

2020

Energy Exploration & Exploitation

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Mechanical vibration can induce coal and gas outburst accidents, and can also promote the exploitation of coalbed methane. In this paper, a vibration-adsorption-desorption experiment system was established, the effects of coal sample particle diameter, gas pressure, and vibration frequency on gas desorption were studied. Mechanical vibration can generate a shear force in the adsorbed gas and promote gas desorption, but there are appropriate vibration parameters. Within the range of experimental parameters, the larger the amplitude, the more favorable for gas desorption. The change rules of gas desorption rate and desorption quantity under different conditions are basically the same, showing a power function shape with time increase, and most of the desorption quantity was completed within the first 5 minutes. The gas desorption rate and desorption quantity were positively related to the gas adsorption pressure. The results have great reference value for preventing gas outbursts and promoting gas exploitation.

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“…constructed a mathematical model using the concept of match sticks and matrix bridges . Yang et al proposed a cubic model, and Wu et al established a model under the assumption that the matrix was embedded in a fracture. In addition, permeability also has a profound effect on the optimization of gas production. − Ho et al and Lee et al showed that the inorganic system mainly affects the flow behavior, and the organic system determines the gas storage capacity.…”

Section: Introductionmentioning

confidence: 99%

Effects of Anisotropic Permeability Evolution on Shale Gas Production: An Internal Swelling Factor Model

et al. 2022

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Considerable attention has been paid to the anisotropic permeability of shale gas reservoirs, but the impacts of heterogeneous internal swelling have rarely been studied. In this research, we propose a new definition of the internal swelling factor (ISF) as the ratio of the increment in the pore adsorption strain to the increment in the matrix adsorption strain. In particular, we pioneered the study of the influence of the boundary conditions on the ISF. A new shale gas production model that considers the anisotropic ISF is proposed. The validity of the model was verified using field data sets obtained from the Marcellus shale and Barnett shale. We examined the influence of the anisotropic ISF on the permeability in all directions. In particular, the influence of the ISF on gas exploitation was characterized. In addition, the sensitivity of the ISF to Langmuir pressure was also analyzed. We obtained the following results. First, under in situ stress boundary conditions, the horizontal ISF was constant as a result of the constant-stress boundary conditions, whereas the vertical ISF increased as a result of the constant-volume boundary conditions during gas depletion. Second, the horizontal permeability was determined by the competition between the effective stress-induced strain and the adsorption strain because of the constant-stress boundary conditions. The horizontal ISF mainly affects the middle and late stages of depletion, whereas the vertical ISF has little effect on both. Third, the large permeability enhances the gas production rate in the early stages of depletion but has relatively little effect on the cumulative gas production volume. The horizontal ISF value is also proportional to the horizontal permeability value. Finally, as the Langmuir pressure of the matrix increases, the ISF value also increases, which leads to an increase in the gas production rate of the inorganic pores, whereas the gas production rate of the matrix decreases because of the decrease in the gas adsorption capacity. As compared with the existing models, this model provides a more accurate way to estimate the impact of the ISF on the shale gas exploration process and to predict the gas depletion characteristics.

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Numerical investigation on the coupled gas-solid behavior of coal using an improved anisotropic permeability model

Cited by 29 publications

References 30 publications

Experimental Study on the Gas Flow Characteristics and Pressure Relief Gas Drainage Effect under Different Unloading Stress Paths

Experimental Study on the Gas Flow Characteristics and Pressure Relief Gas Drainage Effect under Different Unloading Stress Paths

Experimental research on desorption characteristics of gas-bearing coal subjected to mechanical vibration

Effects of Anisotropic Permeability Evolution on Shale Gas Production: An Internal Swelling Factor Model

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