Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China
The research of pore and permeability characteristics of tight sandstone reservoirs in coal-measure is critical for coal-measure gas development. In this study, the pore systems of tight sandstones were studied based on low-field nuclear magnetic resonance (LF-NMR) data. The permeability of tight sa...
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MDPI AG
2022-08-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/15/16/5898 |
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| author | Huazhou Huang Yuantao Sun Xiantong Chang Zhengqing Wu Mi Li Shulei Qu |
| author_facet | Huazhou Huang Yuantao Sun Xiantong Chang Zhengqing Wu Mi Li Shulei Qu |
| author_sort | Huazhou Huang |
| collection | DOAJ |
| description | The research of pore and permeability characteristics of tight sandstone reservoirs in coal-measure is critical for coal-measure gas development. In this study, the pore systems of tight sandstones were studied based on low-field nuclear magnetic resonance (LF-NMR) data. The permeability of tight sandstones was obtained by the tester based on the pulse transient method. The permeability variation with the effective stress, grains, and pore characteristics was analyzed. The results show that the tight sandstone reservoirs in the coal-measure have low total porosity (2.80–4.14%), low effective porosity (0.51–1.56%), and low permeability (0.351 × 10<sup>−6</sup>–13.910 × 10<sup>−6</sup> um<sup>2</sup>). LF-NMR T<sub>2</sub> spectra of the testing sandstones show that the micropores are the most developed, but most of the micropores are immovable pores. The pore characteristics are significantly affected by the grain size of sandstones. The pore connectivity ranks from good to poor with decreasing sandstone particle size. The total porosity and effective porosity increase with the grain size. There is a near-linear negative relationship between permeability and effective stress when the effective stress is between 405 psi and 808 psi. The greater the number of movable pores and the larger the effective porosity, the bigger the permeability of the sandstone. The effective porosity of sandstones is a sensitive indicator for evaluating the permeability of tight sandstone reservoirs. The stress sensitivity coefficient of permeability (S<sub>s</sub>) increases with the increase of the effective stress. The sandstone with lower permeability, smaller effective porosity, and finer grains has a higher S<sub>s</sub>. The particle size of sandstone from coal-measure has a great influence on both permeability and S<sub>s</sub>. The findings will provide a better understanding of the characterization of pore structure and permeability in the process the coal-measure gas extraction, which is useful for the efficient development of coal-measure gas. |
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| issn | 1996-1073 |
| language | English |
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| spelling | doaj.art-7d8d99d9808f4d00ad8f7fc7d0c1c33d2023-11-30T21:18:18ZengMDPI AGEnergies1996-10732022-08-011516589810.3390/en15165898Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, ChinaHuazhou Huang0Yuantao Sun1Xiantong Chang2Zhengqing Wu3Mi Li4Shulei Qu5Jiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Ministry of Education, Xuzhou 221008, ChinaKey Laboratory of Coalbed Methane Resources and Reservoir Formation Process, China University of Mining and Technology, Ministry of Education, Xuzhou 221008, ChinaThe research of pore and permeability characteristics of tight sandstone reservoirs in coal-measure is critical for coal-measure gas development. In this study, the pore systems of tight sandstones were studied based on low-field nuclear magnetic resonance (LF-NMR) data. The permeability of tight sandstones was obtained by the tester based on the pulse transient method. The permeability variation with the effective stress, grains, and pore characteristics was analyzed. The results show that the tight sandstone reservoirs in the coal-measure have low total porosity (2.80–4.14%), low effective porosity (0.51–1.56%), and low permeability (0.351 × 10<sup>−6</sup>–13.910 × 10<sup>−6</sup> um<sup>2</sup>). LF-NMR T<sub>2</sub> spectra of the testing sandstones show that the micropores are the most developed, but most of the micropores are immovable pores. The pore characteristics are significantly affected by the grain size of sandstones. The pore connectivity ranks from good to poor with decreasing sandstone particle size. The total porosity and effective porosity increase with the grain size. There is a near-linear negative relationship between permeability and effective stress when the effective stress is between 405 psi and 808 psi. The greater the number of movable pores and the larger the effective porosity, the bigger the permeability of the sandstone. The effective porosity of sandstones is a sensitive indicator for evaluating the permeability of tight sandstone reservoirs. The stress sensitivity coefficient of permeability (S<sub>s</sub>) increases with the increase of the effective stress. The sandstone with lower permeability, smaller effective porosity, and finer grains has a higher S<sub>s</sub>. The particle size of sandstone from coal-measure has a great influence on both permeability and S<sub>s</sub>. The findings will provide a better understanding of the characterization of pore structure and permeability in the process the coal-measure gas extraction, which is useful for the efficient development of coal-measure gas.https://www.mdpi.com/1996-1073/15/16/5898sandstonepermeabilitypore characteristicspermeability stress sensitivityJixi Basin |
| spellingShingle | Huazhou Huang Yuantao Sun Xiantong Chang Zhengqing Wu Mi Li Shulei Qu Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China Energies sandstone permeability pore characteristics permeability stress sensitivity Jixi Basin |
| title | Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China |
| title_full | Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China |
| title_fullStr | Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China |
| title_full_unstemmed | Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China |
| title_short | Experimental Investigation of Pore Characteristics and Permeability in Coal-Measure Sandstones in Jixi Basin, China |
| title_sort | experimental investigation of pore characteristics and permeability in coal measure sandstones in jixi basin china |
| topic | sandstone permeability pore characteristics permeability stress sensitivity Jixi Basin |
| url | https://www.mdpi.com/1996-1073/15/16/5898 |
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