Experimental study on gas mass transfer process in a heterogeneous coal reservoir

Men, Xinyang; Tao, Shu; Liu, Zhenxing; Tian, Wei; Chen, Shida

doi:10.1016/j.fuproc.2021.106779

Cited by 56 publications

(41 citation statements)

References 27 publications

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“…Taking CBM resources as an example, the geological reserves of shallow CBM in China below 2,000 m are 368,10 billion m 3 . However, because most coal seams in China are soft and low permeability reservoirs, the surface and underground exploitation of CBM is not satisfactory (Regan and Chao, 2014;Tao et al, 2018;Men et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Regional Characteristics of Porosity and Permeability of Dahebian Syncline Coal and Its Application

Zhao

Wei

2022

Front. Earth Sci.

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In order to study the basic properties of coal seam thus to provide reference for coalbed methane (CBM) production, the porosity and permeability of coal from DH and WJZ regions of Dahebian syncline in Liupanshui Coalfield were systematically studied. The results shows that the porosity and permeability of coal samples in DH region are between 7.4–10.1% and 0.01 mD∼0.04 mD respectively. The permeability is obviously anisotropic, and it is distributed in a U-shape along bedding angle. The porosity and permeability in the WJZ region are between 12.4–24.85% and 0.3 mD–4.8 mD, but the correlation of permeability and bedding angle is not obvious. There are many primary cracks in coal matrix of WJZ region, while the coal of DH region is relatively complete. As a result, the porosity and permeability of WJZ coal samples are much higher than that of DH coal samples. With the change of confining pressure, obvious change has taken place in the permeability of coal in the two regions. When the confining pressure decreases from 2 to 8 MPa, the permeability loss rate of coal samples is close to 80%. The internal mechanism of the permeability loss is related to crack closure and plastic deformation caused by confining pressure. In contrast, the porosity and permeability of coal in WJZ region are much higher than those in DH region, which indicates that the permeability of the same coal seam in the same structural will have great differences and inhomogeneities. Therefore, the WJZ region is the preferred area, which can be included in the preferential exploitation plan of CBM. In addition, for the typical syncline gas reservoir in Liupanshui Coalfield, it is necessary to consider the block division according to the porosity and permeability indexes, and select the optimal block and give priority to development of CBM. Furthermore, we should pay attention to the difference and adaptability of CBM development in different regions.

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Section: Introductionmentioning

confidence: 99%

Regional Characteristics of Porosity and Permeability of Dahebian Syncline Coal and Its Application

Zhao

Wei

2022

Front. Earth Sci.

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“…e test site was selected in 2616 Bottom Roadway, and the flow test borehole is 20 m away from the drainage borehole. en, according to the geological conditions of the test site, parameter design is carried out on the drainage borehole of the bottom drainage lane [31][32][33]. e specific parameters are shown in Table 10 below.…”

Section: Field Measurement Investigation Of Effective Extraction Radiusmentioning

confidence: 99%

Research on Influencing Factors of Effective Gas Extraction Radius in Coal Mine Based on Multiple Linear Regression

Shang

Kong

et al. 2022

Advances in Materials Science and Engineering

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In order to analyze the influence degree of different factors on gas extraction radius, on the basis of coal seam gas flow theory and elastic mechanics, considering the influence of coal seepage rate change on gas flow, the COMSOL Multiphysics numerical simulation software is secondarily developed by using the stress-seepage coupling mathematical model of coal and rock containing gas. Taking coal seam No.2 of Juji Coal Mine as an example, the effective extraction radius under different extraction negative pressure, extraction borehole diameter, extraction time, and initial permeability of coal seam are simulated, respectively. Then, the orthogonal test method is used to design different calculation schemes, and the effective extraction radius is used as the judgment index. The simulation software is used to calculate the effective extraction radius corresponding to different influencing factors. SPSS statistical software is used to analyze the parameters. The multivariate linear regression equation of the influencing factors of the effective extraction radius is obtained, and the multivariate linear regression model is established. The results show that the negative pressure of extraction has little effect on the effective extraction radius; the effective extraction radius gradually expands with the increase of extraction time and extraction aperture, but it has certain timeliness. The initial permeability of the coal seam has a great influence on the effective extraction radius. The influence degree of different influencing factors from large to small is the initial permeability of coal seam, extraction time, borehole diameter, and extraction negative pressure. Therefore, the key to improving the effectiveness of gas extraction is to increase the initial permeability of the coal seam before preextraction, ensure sufficient extraction time, appropriately increase the borehole diameter, and improve the negative pressure of extraction. Finally, the gas flow rate is used for a field test, and the measured results are basically consistent with the simulation results, which proves the correctness of the mathematical model of gas-containing coal and the feasibility of using numerical simulation methods to study the effective extraction radius of coal seams.

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“…Low annual production is caused mainly by the low averaging production rate due to various geological and engineering factors (Tao et al, 2014;Ye et al, 2013;Zhao et al, 2015a). Regarding the factors that affect CBM production, permeability is a key geological parameter that cannot be ignored (Men et al, 2021;Zhao et al, 2015a;Chen et al, 2018). The development degree and spatial distribution of cleat system (including butt cleat and face cleat, the angle between the two is $ 90°) have an important impact on coal permeability (Bell, 2006;Laubach et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Advantageous Seepage Channel in Coal Seam and its Effects on the Distribution of High-yield Areas in the Fanzhuang CBM Block, Southern Qinshui Basin, China

Tao

Tian

et al. 2021

Nat Resour Res

Self Cite

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Results of stress sensitivity experiments show that, when the confining pressure reaches 15.5 MPa, six coal cores have strong stress sensitivity effect (SSE) and cleat compressibility varying from 0.0286 to 0.0725 MPa À1 . The development of coalbed methane (CBM) is a process of drainage and pressure reduction, which causes inevitable stress-related damage to coal reservoirs. CBM production is affected by different stress-related damage levels, and the damage level depends on different reservoir conditions, working systems, and development stages. The Gu, Huagu, and Pu-Punan zones have high-yield wells with NW-SE distribution, while the Huayna and Huaxi zones have high-yield wells with NE-SW distribution. Based on the stress damage mechanism of reservoir permeability, the factors that control SSE are tectonic stress field, reservoir pressure, and fracture pressure, which in turn affect the productivity changes of CBM wells.

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Experimental study on gas mass transfer process in a heterogeneous coal reservoir

Cited by 56 publications

References 27 publications

Regional Characteristics of Porosity and Permeability of Dahebian Syncline Coal and Its Application

Regional Characteristics of Porosity and Permeability of Dahebian Syncline Coal and Its Application

Research on Influencing Factors of Effective Gas Extraction Radius in Coal Mine Based on Multiple Linear Regression

Advantageous Seepage Channel in Coal Seam and its Effects on the Distribution of High-yield Areas in the Fanzhuang CBM Block, Southern Qinshui Basin, China

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