Improved apparent permeability models of gas flow in coal with Klinkenberg effect

Wang, Gongda; Ren, Ting X; Wang, Kai; Zhou, Aitao

doi:10.1016/j.fuel.2014.02.066

Cited by 107 publications

(51 citation statements)

References 57 publications

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“…It could be (b) The variations of ion contents in the reaction solutions of Tunlan coal samples were similar to those observed for Malan coal samples. However, the corresponding concentrations of Ca 2+ , Mg 2+ , HCO 3 − , and CO 3 2− ions were higher for Tunlan coal samples. In contrast, the concentrations of K + and Na + ions in the reaction solution of for Tunlan coal samples were lower than those for Malan coal samples.…”

Section: Variable Features Of Pores and Microfracturesmentioning

confidence: 83%

“…To investigate possible reactions of the major minerals in the coal samples, the corresponding variations of the main ions in solution (K + , Na + , Ca 2+ , Mg 2+ , HCO 3 − , and CO 3 2− ) were measured ( Figure 3). …”

Section: Ion Contentmentioning

confidence: 99%

“…It fully demonstrates that CO 2 injection can increase the coal-bed methane production. Meanwhile, the concentrations of K + + Na + , HCO 3 − , Ca 2+ , Mg 2+ However, the experiments presented in this study were performed on the certain coal samples without consideration of the in-situ stress, temperature and adsorbed gas in nanopores. These conditions may influence the acidizing effect in CO 2 -ECBM.…”

Section: Implication For Co 2 -Ecbmmentioning

confidence: 99%

“…Coal-bed methane (CBM) represents a highly efficient source of clean energy and is considered an important promoter of the energy production and consumption revolution in China. However, low permeability of coal bed reservoirs in China is a major challenge faced by the CBM industry, leading to a low yield of the existing CBM wells [2][3][4]. Various permeability enhancement techniques such as hydraulic fracturing, nitrogen foam fracturing, and methane displacement by CO 2 have been employed to promote transport of CBM and increase its recovery rate [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study of CO2-Water-Mineral Interactions and Their Influence on the Permeability of Coking Coal and Implications for CO2-ECBM

Guo

Wang

et al. 2018

Minerals

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Abstract:Coal permeability is one of the most critical parameters affecting gas flow behavior during coalbed methane (CBM) production. However, little research has been conducted on how permeability evolves after CO 2 injection in coking coal. Hence, examining possible chemical interactions between coal minerals, water, and injected CO 2 can be very helpful to better characterize coking coal. In this study, coking coal specimens obtained from the Malan and Tunlan mines located in the Gujiao block of the Qinshui basin were treated with water and CO 2 to achieve a better understanding of their dissolution kinetics, pore structure, and permeability. It was found that the relative carbonate mineral content decreases with time, while the relative clay mineral content increases after the reaction with CO 2 and water. Scanning electron microscopy (SEM) confirmed these mineral alteration phenomena. Carbonate minerals (calcite, dolomite) dissolve faster than clay minerals (montmorillonite, illite and kaolinite). In particular, the dissolution rates of Ca 2+ in carbonate minerals increases with decreasing temperature (25-45 • C) and pH (4.3-6.3), and the dissolution rate of Ca 2+ ions in the calcite reaction solution is higher than that in the dolomite solution. In addition, the results of low-pressure nitrogen adsorption analysis showed that CO 2 injection can enlarge smaller size pores into larger size pores and change the overall pore size distribution. Therefore, CO 2 injection can increase the porosity of coal beds and ultimately their permeability, which in turn facilitates CBM production.

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Section: Variable Features Of Pores and Microfracturesmentioning

confidence: 83%

Section: Ion Contentmentioning

confidence: 99%

Section: Implication For Co 2 -Ecbmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Study of CO2-Water-Mineral Interactions and Their Influence on the Permeability of Coking Coal and Implications for CO2-ECBM

Guo

Wang

et al. 2018

Minerals

View full text Add to dashboard Cite

show abstract

“…Because of its easy absorption characteristics, the methane flow in a coal matrix varies from that of nonadsorption gases, such as the modified FE model proposed by Zhang et al (2005), that better describe the methane permeability in the matrix by evaluating the methane seepage characteristics in the deformed matrix. Wang et al (2014) reconstructed the permeability model by monitoring the change of gas slippage in the shrinking matrix. Previous studies showed that changes in the pore structure exerted by methane adsorption can have a great effect on methane seepage.…”

Section: Introductionmentioning

confidence: 99%

Effect of adsorption-induced matrix deformation on coalbed methane transport analyzed using fractal theory

Zhou

Yang

et al. 2015

Journal of Natural Gas Science and Engineering

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Creep characteristics and constitutive model of coal under triaxial stress and gas pressure

Zhang

Gao

et al. 2019

Energy Science & Engineering

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Creep behavior is one of the most important mechanical behaviors of coal. In the present study, we systematically carried out a series of creep experiments of briquette samples under triaxial compression and gas pressure. The experimental results showed that the creep deformation characteristics of coal were related to deviatoric stress and gas pressure. The accelerating creep stage initiated when the deviatoric stress reached or exceeded the yield stress until failure took place. In contrast, when the deviatoric stress was less than the yield strength, only transient and steady creep stage occurred. Besides, gas pressure played a positive role in the creep process of coal. The axial strain of coal slightly increased with gas pressure (range from 0.13 to 0.40 MPa) when the effective triaxial stress remained constant. For example, in the steady creep stage (σ 1 = 9 MPa, p = 0.13 MPa), the axial strain of sample S 1 is 2.710% and that of sample S 2 is 3.361%, that is, coal samples with high gas pressure have higher axial strain. Moreover, gas pressure has two main effects on the mechanical behavior of coal. One is that the coal adsorbs gas molecules resulting in swelling strain and swelling stress, and the other is that the gas pressure may compress the coal particles. Considering the swelling stress and gas pressure, we intensively studied the effective stress formula of coal containing gas. Then, the effective stress was taken into consideration in the nonlinear Nishihara creep model. Furthermore, the tertiary creep factor n was introduced in the nonlinear model to control the creep deformation evolution with time so that the nonlinear model could accurately describe the full creep stage of coal. In contrast, due to the lack of such a controlling parameter, the Nishihara model failed to reproduce the accelerating creep stage. K E Y W O R D Scoal, creep model, effective stress, gas pressure, swelling stress, triaxial compression | INTRODUCTIONCreep behavior is one of the fundamental mechanical properties of coal or rock, associated with the stability of many buildings and underground structures in mining and rock engineering, such as roadways, tunnels, and dams. It is important to have a precise understanding of the creep or timedependent behavior of coal or rock, which may prevent coal 502 | ZHANG et Al. Highlights• The coupling effect of triaxial stress and gas pressure on coal was investigated. • The gas pressure played a positive role in the creep process of coal. • The effective stress of gas-filled coal was intensively studied. • The effective stress was considered in the nonlinear Nishihara creep model of coal, which could accurately reproduce the three creep stages, especially the accelerating creep stage.How to cite this article: Zhang L, Li X-C, Gao J-X, An Z-X, Yang X-H, Nie B-S. Creep characteristics and constitutive model of coal under triaxial stress and gas pressure. Energy Sci Eng. 2020;8:501-514. https ://doi.

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Improved apparent permeability models of gas flow in coal with Klinkenberg effect

Cited by 107 publications

References 57 publications

Experimental Study of CO2-Water-Mineral Interactions and Their Influence on the Permeability of Coking Coal and Implications for CO2-ECBM

Experimental Study of CO2-Water-Mineral Interactions and Their Influence on the Permeability of Coking Coal and Implications for CO2-ECBM

Effect of adsorption-induced matrix deformation on coalbed methane transport analyzed using fractal theory

Creep characteristics and constitutive model of coal under triaxial stress and gas pressure

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