Investigation on parameters optimization for gas permeability testing of concrete: Inlet-gas pressure and confining pressure

2020 ◽  
Vol 250 ◽  
pp. 118901 ◽  
Author(s):  
Rusheng Qian ◽  
Jiashun Shi ◽  
Yan Li ◽  
Wei Chen ◽  
Guojian Liu ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Parameters Optimization

Experimental Study on Microscopic Structure and Permeability of Tectonic Soft Coal

2013 ◽  
Vol 734-737 ◽  
pp. 241-245
Author(s):  
Kui Gao ◽  
Wei Yi Xue
Keyword(s):  
Gas Permeability ◽  
Great Influence ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Microscopic Structure ◽  
Klinkenberg Effect ◽  
Coal Permeability ◽  
Typical Sample ◽  
Soft Coal ◽  
Soft Coal Seam

To analyze the mining effect to gas permeability of tectonic soft coal seam, we choose typical sample from tectonic soft coal, study the gas permeability and microstructure. The results suggest that tectonic soft coal has been badly destroyed, and its micro fracture pore develops. Confining pressure has a great influence on the permeability of tectonic soft coal. When gas pressure remains constant, with the increase of confining pressure of tectonic soft coal permeability began to decrease very fast. But when decreasing to a certain degree, it changes slowly; when confining pressure remains constant, with the increase of gas pressure, permeability of tectonic soft coal first decreases and then increases. Under the condition of low gas pressure, tectonic soft coal permeability shows a significant Klinkenberg effect.

scholarly journals Coupled Effects of Stress, Moisture Content and Gas Pressure on the Permeability Evolution of Coal Samples: A Case Study of the Coking Coal Resourced from Tunlan Coalmine

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1653
Author(s):  
Guofu Li ◽  
Yi Wang ◽  
Junhui Wang ◽  
Hongwei Zhang ◽  
Wenbin Shen ◽  
...  
Keyword(s):  
Moisture Content ◽  
Coalbed Methane ◽  
Gas Permeability ◽  
Axial Stress ◽  
Gas Pressure ◽  
Pressure Curve ◽  
Permeability Evolution ◽  
Confining Stress ◽  
Qinshui Basin ◽  
Gas Seepage

Deep coalbed methane (CBM) is widely distributed in China and is mainly commercially exploited in the Qinshui basin. The in situ stress and moisture content are key factors affecting the permeability of CH4-containing coal samples. Therefore, considering the coupled effects of compressing and infiltrating on the gas permeability of coal could be more accurate to reveal the CH4 gas seepage characteristics in CBM reservoirs. In this study, coal samples sourced from Tunlan coalmine were employed to conduct the triaxial loading and gas seepage tests. Several findings were concluded: (1) In this triaxial test, the effect of confining stress on the permeability of gas-containing coal samples is greater than that of axial stress. (2) The permeability versus gas pressure curve of coal presents a ‘V’ shape evolution trend, in which the minimum gas permeability was obtained at a gas pressure of 1.1MPa. (3) The gas permeability of coal samples decreased exponentially with increasing moisture content. Specifically, as the moisture content increasing from 0.18% to 3.15%, the gas permeability decreased by about 70%. These results are expected to provide a foundation for the efficient exploitation of CBM in Qinshui basin.

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

Effects of gas pressure and confining pressure on gas flow behavior in saturated cohesive soils with low permeability

2019 ◽  
Vol 260 ◽  
pp. 105241 ◽  
Author(s):  
Long Xu ◽  
Fanghua Zhu ◽  
Fusheng Zha ◽  
Chengfu Chu ◽  
Chengbin Yang
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Low Permeability ◽  
Cohesive Soils

Experimental and Numerical Study of the Influence of Gas Pressure on Gas Permeability in Pressure Relief Gas Drainage

2018 ◽  
Vol 124 (3) ◽  
pp. 995-1015 ◽  
Author(s):  
Cun Zhang ◽  
Lei Zhang ◽  
Shihao Tu ◽  
Dingyi Hao ◽  
Teng Teng
Keyword(s):  
Gas Permeability ◽  
Numerical Study ◽  
Gas Pressure ◽  
Pressure Relief ◽  
Gas Drainage

Permeability Changes of Coal Cores and Briquettes under Tri-Axial Stress Conditions

2014 ◽  
Vol 59 (4) ◽  
pp. 1131-1140
Author(s):  
Mirosław Wierzbicki ◽  
Pavel Konečný ◽  
Alena Kožušníková
Keyword(s):  
Gas Permeability ◽  
Coal Dust ◽  
Axial Stress ◽  
Empirical Relation ◽  
Confining Pressure ◽  
Good Correspondence ◽  
State Of Stress ◽  
Good Repeatability ◽  
Axial State ◽  
Methane Capacity

Abstract The paper is dealing with the permeability of coal in triaxial state of stress. The permeability of coal, besides coal’s methane capacity, is the main parameter determining the quantity of methane inflow into underground excavations. The stress in a coal seam is one of the most important factors influencing coal permeability therefore the permeability measurements were performed in tri-axial state of stress. The hydrostatic three-axial state of stress was gradually increased from 5 MPa with steps of 5 MPa up to a maximum of 30 MPa. Nitrogen was applied as a gas medium in all experiments. The results of the permeability measurements of coal cores from the “Zofiówka” mine, Poland, and three mines from the Czech Republic are presented in this paper. As a “reference”, permeability measurements were also taken for coal briquettes prepared from coal dust with defined porosity. It was confirmed that the decreasing porosity of coal briquettes affects the decreasing permeability. The advantage of experimentation on coal briquettes is its good repeatability. From the experimental results, an empirical relation between gas permeability and confining pressure has also been identified. The empirical relation for coal briquettes is in good correspondence with published results. However, for coal cores, the character of change differs. The influence of confining pressure has a different character and the decrease in permeability is stronger due to the increasing confining pressure

scholarly journals Study on the impact of confining pressure on gas permeability of tight sandstone cores

2021 ◽  
Vol 2076 (1) ◽  
pp. 012006
Author(s):  
Jianxiang Tong ◽  
Hengyang Wang ◽  
Yuyi Wang ◽  
Ya Zhang ◽  
Xiaohe Huang
Keyword(s):  
Power Function ◽  
Rate Coefficient ◽  
Gas Permeability ◽  
Confining Pressure ◽  
Experimental Sample ◽  
Tight Sandstone ◽  
Change Rate ◽  
Shengli Oilfield ◽  
Confining Pressures ◽  
The Impact

Abstract Taking the tight sandstone core of Shengli Oilfield as the experimental sample, this paper studies the permeability variation of the tight sandstone under different confining pressures. The experimental results show that when the pore pressure is constant, the measured gas permeability of core decreases with the increase of confining pressure. Power function is more reasonable to describe the influence of confining pressure on permeability of tight sandstone between power function and exponential function. Analyze the impact of confining pressure on gas permeability of tight sandstone cores by using permeability change rate coefficient D and coefficient S.

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