A permeability model for gas flow in coal considering the water content and slippage effect

2020 ◽  
Vol 3 (4) ◽  
pp. 305
Author(s):  
Jianhua Li ◽  
Bobo Li ◽  
Jiang Xu ◽  
Zhihe Wang ◽  
Zheng Gao ◽  
...  
Keyword(s):  
Water Content ◽  
Gas Flow ◽  
Permeability Model ◽  
Slippage Effect

A permeability model for gas flow in coal considering the water content and slippage effect

2020 ◽  
Vol 3 (4) ◽  
pp. 305
Author(s):  
Zheng Gao ◽  
Yao Zhang ◽  
Jiang Xu ◽  
Zhihe Wang ◽  
Bobo Li ◽  
...  
Keyword(s):  
Water Content ◽  
Gas Flow ◽  
Permeability Model ◽  
Slippage Effect

scholarly journals Thermos-Solid-Gas Coupling Dynamic Model and Numerical Simulation of Coal Containing Gas

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xiao Fukun ◽  
Meng Xin ◽  
Li Lianchong ◽  
Liu Jianfeng ◽  
Liu Gang ◽  
...  
Keyword(s):  
Principal Stress ◽  
Dynamic Model ◽  
Gas Flow ◽  
Flow Behavior ◽  
Coupling Model ◽  
Gas Pressure ◽  
Permeability Model ◽  
Gas Seepage ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

Based on gas seepage characteristics and the basic thermo-solid-gas coupling theory, the porosity model and the dynamic permeability model of coal body containing gas were derived. Based on the relationship between gas pressure, principal stress and temperature, and gas seepage, the thermo-solid-gas coupling dynamic model was established. Initial values and boundary conditions for the model were determined. Numerical simulations using this model were done to predict the gas flow behavior of a gassy coal sample. By using the thermo-solid-gas coupling model, the gas pressure, temperature, and principal stress influence, the change law of the pressure field, displacement field, stress field, temperature field, and permeability were numerically simulated. Research results show the following: (1) Gas pressure and displacement from the top to the end of the model gradually reduce, and stress from the top to the end gradually increases. The average permeability of the Y Z section of the model tends to decrease with the rise of the gas pressure, and the decrease amplitude slows down from the top of the model to the bottom. (2) When the principal stress and temperature are constant, the permeability decreases first and then flattens with the gas pressure. The permeability increases with the decrease of temperature while the gas pressure and principal stress remain unchanged.

Testing Study on the Effects of Water Content on Permeability for Coal

2014 ◽  
Vol 580-583 ◽  
pp. 201-204
Author(s):  
Chun Hui Zhang ◽  
Xiao Pan Xu
Keyword(s):  
Water Content ◽  
Pore Pressure ◽  
Coal Sample ◽  
Channel Wall ◽  
Confining Pressure ◽  
Liaoning Province ◽  
Air Drying ◽  
Slippage Effect

To obtain the effects of water content on the permeability of coal, briquette specimen were obtained from Wulong Mine, Liaoning Province. The permeability of the air drying, bounding water and saturating specimens were tested with self-made equipment respectively, and the effects of water content on permeability for coal were studied. The results showed that: (1)The permeability of specimens decreases with confining pressure increasing, and the air drying and bounding water specimens take on obvious slippage effect. However the saturated specimens never take on slippage effects. It is because the channels of saturated coal sample are occupied by water. When the gas goes through specimens, gas never is absorbed. Collision between gas and the channel wall decreases, and the slippage effect disappears. (2) With water content increasing, the permeability of specimens decreases. (3)The permeability of specimens increases when pore pressure increases.

General slip regime permeability model for gas flow through porous media

2016 ◽  
Vol 28 (7) ◽  
pp. 072003 ◽  
Author(s):  
Bo Zhou ◽  
Peixue Jiang ◽  
Ruina Xu ◽  
Xiaolong Ouyang
Keyword(s):  
Porous Media ◽  
Gas Flow ◽  
Flow Through Porous Media ◽  
Permeability Model ◽  
Slip Regime ◽  
Flow Through

A fractal permeability model for gas flow through dual-porosity media

2012 ◽  
Vol 111 (2) ◽  
pp. 024316 ◽  
Author(s):  
Qian Zheng ◽  
Boming Yu
Keyword(s):  
Gas Flow ◽  
Dual Porosity ◽  
Permeability Model ◽  
Flow Through

scholarly journals Constraints of Pore-Bulk Strain Ratio and Interference Time on the Evolution of Coal Permeability during CO2 Injection

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Guannan Liu ◽  
Jishan Liu ◽  
Feng Gao
Keyword(s):  
Gas Flow ◽  
Strain Ratio ◽  
Reciprocal Theorem ◽  
Co2 Injection ◽  
Gas Sorption ◽  
Ultimate State ◽  
Initial State ◽  
Permeability Model ◽  
Coal Permeability ◽  
Bulk Strain

CO2 injection into coal seam triggers a series of processes that are coupled all together through a permeability model. Previous studies have shown that current permeability models cannot explain experimental data as reported in the literature. This knowledge gap defines the goal of this study. We hypothesize that this failure originates from the assumption that the pore strain is the same as the bulk strain in order to satisfy the Betti-Maxwell reciprocal theorem. This assumption is valid only for the initial state without gas sorption and deformation and for the ultimate state with uniform gas sorption and uniform deformation within the REV (representative elementary volume). In this study, we introduce the pore-bulk strain ratio and interference time to characterize the process of gas sorption and its associated nonuniform deformation from the initial state to the ultimate state. This leads to a new nonequilibrium permeability model. We use the model to fully couple the coal deformation and gas flow. This new coupled model captures the impact of coal local transient behaviors on gas flow. Results of this study clearly show that coal permeability is constrained by the magnitudes of initial and ultimate pore-bulk strain ratios and interference time, that current permeability data in the literature are within these bounds, and that the evolutions of coal permeability all experience similar stages from the initial value to the ultimate one.

Factors Affecting Water Content Needed to Passivate Titanium in Chlorine

CORROSION ◽  
1967 ◽  
Vol 23 (4) ◽  
pp. 88-97 ◽  
Author(s):  
E. E. MILLAWAY ◽  
M.H. KLEINMAN
Keyword(s):  
Water Content ◽  
Gas Flow ◽  
Titanium Surface ◽  
Surface Condition ◽  
Flow Conditions ◽  
Reaction Sequence ◽  
Factors Affecting ◽  
Chlorine Gas ◽  
Titanium Surfaces ◽  
Static Conditions

Abstract Titanium generally is reactive to dry, gaseous chlorine. A small amount of water in gaseous chlorine will inhibit this reaction. A testing program showed the amount of water required for inhibition varied with exposure conditions from about 0.20 to 1.1 over the range of about 25 to 175 C (77–347 F). When water content in the gaseous chlorine is sufficient titanium can be considered passive. Data were obtained mostly by scratching to expose fresh titanium surfaces to gaseous chlorine and observing reactions. Under some conditions a definite reaction sequence often took place, which could be observed from initiation to ignition of a specimen. Some data were obtained from exposure of undisturbed titanium specimens in gaseous chlorine. The water content required to passivate titanium in chlorine gas was found to be dependent upon temperature, gas flow rate and chlorine pressure. It was affected also by titanium surface condition, some roughened surfaces showing increased reactivity. Under static conditions involving chlorine of high purity, water required was greater than under flow conditions in dried, crude Hooker cell chlorine. Undisturbed titanium surfaces exposed at 195 C (382 F) for over a year showed no reaction when chlorine water content was 1.5 percent or more.

An Experimental Study on the Slippage Effect of Gas Flow in a Compact Rock

2016 ◽  
Vol 112 (1) ◽  
pp. 117-137 ◽  
Author(s):  
H. L. Wang ◽  
W. Y. Xu ◽  
M. Cai ◽  
J. Zuo
Keyword(s):  
Experimental Study ◽  
Gas Flow ◽  
Slippage Effect ◽  
Compact Rock

Laboratory measurement and interpretation of nonlinear gas flow in shale

2015 ◽  
Vol 26 (06) ◽  
pp. 1550063 ◽  
Author(s):  
Yili Kang ◽  
Mingjun Chen ◽  
Xiangchen Li ◽  
Lijun You ◽  
Bin Yang
Keyword(s):  
Pore Pressure ◽  
Gas Flow ◽  
Gas Adsorption ◽  
Slip Flow ◽  
Transition Flow ◽  
Confining Stress ◽  
Slippage Effect ◽  
Longmaxi Shale ◽  
Close Relationship ◽  
Flow Mechanisms

Gas flow mechanisms in shale are urgent to clarify due to the complicated pore structure and low permeability. Core flow experiments were conducted under reservoir net confining stress with samples from the Longmaxi Shale to investigate the characteristics of nonlinear gas flow. Meanwhile, microstructure analyses and gas adsorption experiments are implemented. Experimental results indicate that non-Darcy flow in shale is remarkable and it has a close relationship with pore pressure. It is found that type of gas has a significant influence on permeability measurement and methane is chosen in this work to study the shale gas flow. Gas slippage effect and minimum threshold pressure gradient weaken with the increasing backpressure. It is demonstrated that gas flow regime would be either slip flow or transition flow with certain pore pressure and permeability. Experimental data computations and microstructure analyses confirm that hydraulic radius of flow tubes in shale are mostly less than 100 nm, indicating that there is no micron scale pore or throat which mainly contributes to flow. The results are significant for the study of gas flow in shale, and are beneficial for laboratory investigation of shale permeability.

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