Insight into Gas Threshold Pressure Gradient and Permeability of Coal Seam: Principle and Method for Field Test
Publication: Journal of Energy Engineering
Volume 149, Issue 6
Abstract
The flow regime of gas migration and production in a low-permeability coal seam includes desorption, diffusion, low-velocity nonlinear seepage, and linear seepage. However, the current field test methods of coal seam permeability in China are all based on linear seepage theory, leaving out the low-velocity nonlinear seepage with gas threshold pressure gradient. Therefore, a field test method for gas threshold pressure gradient and permeability is established in this paper. First, the two upward cross seam boreholes (the piezometric borehole and gas extraction borehole) are constructed in the untapped area of the floor drainage roadway with the low-permeability coal seam. After sealing the holes, the pressure measurement and gas extraction are carried out, respectively. Then, a radial flow mathematical model considering the gas threshold pressure gradient was constructed, and the model was solved by the COMSOL Multiphysics software. Finally, the gas threshold pressure gradient and permeability of the coal seam were obtained by fitting the simulated data of gas pressure and flow to the measured data in the field. The method was applied to the test of gas threshold pressure gradient and permeability before and after the hydraulic punching. Field test results show that this method can more accurately characterize the permeability in the gas extraction process of low-permeability coal seam than the traditional method.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
The work was supported by the National Natural Science Foundation of China (42230804 and 42072193) and the Natural Science Foundation of Henan Province (222300420173). We are also grateful for the constructive comments by reviewers and editors on an earlier draft of this manuscript.
References
Cheng, L., and Y. Shi. 2020. “Coupling model of gas seepage in low permeability coal seam considering start-up pressure gradient and its application.” Min. Saf. Environ. Prot. 47 (2): 70–75.
Cheng, W. M., Z. Liu, H. Yang, and W. Y. Wang. 2018. “Non-linear seepage characteristics and influential factors of water injection in gassy seams.” Exp. Therm. Fluid Sci. 91 (Feb): 41–53. https://doi.org/10.1016/j.expthermflusci.2017.10.002.
Chinese Standard. 2009a. The method of injection/falloff well test for coalbed methane well. GB/T 24504-2009. Beijing: Chinese Standard.
Chinese Standard. 2009b. Standardization administration of the People’s Republic China: Code for coal mine gas drainage. AQ 1027-2006. Beijing: Chinese Standard.
Diwu, P. X., T. J. Liu, Z. J. You, B. Y. Jiang, and J. Zhou. 2018. “Effect of low velocity non-Darcy flow on pressure response in shale and tight oil reservoirs.” Fuel 216 (Mar): 398–406. https://doi.org/10.1016/j.fuel.2017.11.041.
Dong, J., Y. P. Cheng, K. Jin, H. Zhang, Q. H. Liu, J. Y. Jiang, and B. Hu. 2017. “Effects of diffusion and suction negative pressure on coalbed methane extraction and a new measure to increase the methane utilization rate.” Fuel 197 (Jun): 70–81. https://doi.org/10.1016/j.fuel.2017.02.006.
Dong, M., X. Shi, S. Ling, B. Zhang, and X. Li. 2019. “Effect of dynamic pseudo threshold pressure gradient on well production performance in low-permeability and tight oil reservoirs.” J. Pet. Sci. Eng. 173 (Feb): 69–76. https://doi.org/10.1016/j.petrol.2018.09.096.
Engelhardt, W., and W. Tunn. 1955. The flow of fluids through sandstones. Urbana, IL: State Geological Survey.
Feng, G. J., X. Z. Zhao, M. Wang, Y. Song, S. J. Zheng, Y. He, and Z. J. You. 2022. “Fractal pore and its impact on gas adsorption capacity of outburst coal: Geological significance to coalbed gas occurrence and outburst.” Adsorpt. Sci. Technol. 2022 (Nov): 4273900. https://doi.org/10.1155/2022/4273900.
Feng, W. G. 1986. “Non-darcy low velocity unsteady flow of natural gas.” Nat. Gas Ind. 6 (3): 49–56.
Fu, X., F. Agostini, F. Skoczylas, and L. Jeannin. 2015. “Experimental study of the stress dependence of the absolute and relative permeabilities of some tight gas sandstones.” Int. J. Rock Mech. Min. Sci. 77 (Jul): 36–43. https://doi.org/10.1016/j.ijrmms.2015.03.005.
Gao, H., and H. Z. Li. 2016. “Pore structure characterization, permeability evaluation and enhanced gas recovery techniques of tight gas sandstones.” J. Nat. Gas Sci. Eng. 28 (Jan): 536–547. https://doi.org/10.1016/j.jngse.2015.12.018.
Guo, H. J., H. L. Tang, Y. C. Wu, K. Wang, and C. Xu. 2020. “Gas seepage in underground coal seams: Application of the equivalent scale of coal matrix-fracture structures in coal permeability measurements.” Fuel 288 (Mar): 119641. https://doi.org/10.1016/j.fuel.2020.119641.
Guo, H. Y., and X. B. Su. 2010a. “An experimental measurement of the threshold pressure gradient of coal reservoirs and its significance.” Nat. Gas Ind. 30 (6): 52–54. https://doi.10.3787/j.issn.1000-0976.2010.06.014.
Guo, H. Y., and X. B. Su. 2010b. “Research on the mechanism of gas emission inhibition in water-flooding coal seam.” J. China Coal Soc. 35 (6): 928–931. https://doi.10.13225/j.cnki.jccs.2010.06.021.
Hansbo, S. 1960. Consolidation of clay, with special reference to influence of vertical sand drains: A study made in connection with full-scale investigations at Ska-Edeby. Göteborg, Sweden: Chalmers Univ. of Technology.
Hodot, B. 1966. Outburst of coal and coalbed gas. [In Chinese.] Beijing: China Coal Industry Press.
Kang, Y. S., L. Z. Sun, B. Zhang, J. Y. Gu, and D. L. Mao. 2017. “Discussion on classification of coalbed reservoir permeability in China.” Supplement, J. China Coal Soc. 42 (S1): 186–194. https://doi.org/10.13225/j.cnki.jccs.2016.1293.
Li, G. Q., S. P. Meng, and B. Y. Wang. 2014. “Diffusion and seepage mechanisms of high rank coal-bed methane reservoir and its numerical simulation at early drainage rate.” J. China Coal Soc. 39 (9): 1919–1926. https://doi:10.13225/j.cnki.jccs.2014.8024.
Liu, D., G. Zhou, Y. Miao, S. Guo, and J. Zhang. 2021. “Numerical simulation investigation for stress deformation and water injection seepage of coal microstructure under uniaxial compression.” J. Energy Eng. 147 (5): 04021036. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000786.
Liu, T., and B. Q. Lin. 2019. “Time-dependent dynamic diffusion processes in coal: Model development and analysis.” Int. J. Heat Mass Transfer 134 (May): 1–9. https://doi.org/10.1016/j.ijheatmasstransfer.2019.01.005.
Liu, W., C. He, Y. P. Qin, and P. Liu. 2018. “Inversion of gas permeability coefficient of coal particle based on Darcy’s permeation model.” J. Nat. Gas Sci. Eng. 50 (Feb): 240–249. https://doi.org/10.1016/j.jngse.2017.12.017.
Liu, W. C., J. Yao, Z. X. Chen, and W. Y. Zhu. 2019. “An exact analytical solution of moving boundary problem of radial fluid flow in an infinite low-permeability reservoir with threshold pressure gradient.” J. Pet. Sci. Eng. 175 (Apr): 9–21. https://doi.org/10.1016/j.petrol.2018.12.025.
Ma, G., X. B. Su, and Q. X. Wei. 2009. “Determination method of coal gas drainage radius based on methane flow state.” J. China Coal Soc. 34 (4): 501–504.
Miller, R. J., and P. F. Low. 1963. “Threshold gradient for water flow in clay systems.” Soil Sci. Soc. Am. J. 27 (6): 605–609. https://doi.org/10.2136/sssaj1963.03615995002700060013x.
Nie, R. S., Y. M. Wang, Y. L. Kang, and Y. L. Jia. 2018. “Modeling the characteristics of Bingham porous-flow mechanics for a horizontal well in a heavy oil reservoir.” J. Pet. Sci. Eng. 171 (Dec): 71–81. https://doi.org/10.1016/j.petrol.2018.07.026.
Pan, Z. J., L. D. Connell, M. Camilleri, and L. Connelly. 2010. “Effects of matrix moisture on gas diffusion and flow in coal.” Fuel 89 (11): 3207–3217. https://doi.org/10.1016/j.fuel.2010.05.038.
Pan, Z. J., and D. A. Wood. 2015. “Coalbed methane (CBM) exploration, reservoir characterization, production, and modeling: A collection of published research (2009–2015).” J. Nat. Gas Sci. Eng. 26 (Mar): 1472–1484. https://doi.org/10.1016/j.jngse.2015.07.049.
Pang, M. Q., J. Ba, and J. M. Carcione. 2021. “Characterization of gas saturation in tight-sandstone reservoirs with rock-physics templates based on seismic Q.” J. Energy Eng. 147 (3): 04021011. https://doi.org/10.1061/(ASCE)EY.1943-7897.0000761.
Prada, A., and F. Civan. 1999. “Modification of Darcy’s law for the threshold pressure gradient.” J. Pet. Sci. Eng. 22 (4): 237–240. https://doi.org/10.1016/S0920-4105(98)00083-7.
Rees, D., and A. Bassom. 2015. “Unsteady thermal boundary layer flows of a Bingham fluid in a porous medium.” Int. J. Heat Mass Transfer 82 (Mar): 460–467. https://doi.org/10.1016/j.ijheatmasstransfer.2014.10.047.
Song, H. Q., Y. Cao, M. X. Yu, Y. H. Wang, J. E. Killough, and J. Leung. 2015. “Impact of permeability heterogeneity on production characteristics in water-bearing tight gas reservoirs with threshold pressure gradient.” J. Nat. Gas Sci. Eng. 22 (Jan): 172–181. https://doi.org/10.1016/j.jngse.2014.11.028.
Song, J. 2016. Study on the stimulation mechanism and technology of coalbed methane reservoir by surface modification. Henan, China: Henan Polytechnic Univ.
Song, J. Z., H. Y. Zhang, S. Y. Yu, and X. B. Su. 2022. “Application of integrated drilling and stamping technology in gas extraction through layer drilling.” Energy Explor. Exploit. 40 (4): 1113–1130. https://doi.org/10.1177/01445987221078053.
Su, X. B., F. Li, L. N. Su, and Q. Wang. 2020. “The experimental study on integrated hydraulic fracturing of coal measures gas reservoirs.” Fuel 270 (Jun): 117527. https://doi.org/10.1016/j.fuel.2020.117527.
Su, X. B., and G. Ma. 2014. Theory and technology of underground hydraulic strengthening in coal mine. Beijing: Science Press.
Su, X. B., and G. Ma. 2017. Fracture network stimulating technology and its application for unconventional natural gas reservoir in coal measure. Beijing: Science Press.
Su, X. B., Q. Wang, J. X. Song, P. H. Chen, S. Yao, J. T. Hong, and F. D. Zhou. 2017. “Experimental study of water blocking damage on coal.” J. Pet. Sci. Eng. 156 (Jul): 654–661. https://doi.org/10.1016/j.petrol.2017.06.048.
Su, X. B., S. Yao, J. X. Song, Q. Wang, and F. Li. 2019. “The discovery and control of slug flow in coalbed methane reservoir.” J. Pet. Sci. Eng. 172 (Jan): 115–123. https://doi.org/10.1016/j.petrol.2018.09.055.
Tan, Y. L., Z. J. Pan, J. S. Liu, J. H. Kang, F. B. Zhou, L. D. Connell, and Y. X. Yang. 2018. “Experimental study of impact of anisotropy and heterogeneity on gas flow in coal. Part I: Diffusion and adsorption.” Fuel 232 (15): 444–453. https://doi.org/10.1016/j.fuel.2018.05.173.
Tian, L., Y. Cao, X. Chai, T. Liu, P. Feng, H. Feng, D. Zhou, B. Shi, R. Oestreich, and G. Rodvelt. 2015. “Best practices for the determination of low-pressure/permeability coalbed methane reservoirs, Yuwu Coal Mine, Luan mining area, China.” Fuel 160 (Nov): 100–107. https://doi.org/10.1016/j.fuel.2015.07.082.
Wang, Q., X. B. Su, Y. L. Feng, and H. Wang. 2021a. “Experimental study of gas-water two-phase flow patterns in fracture: Implication for enhancing coalbed methane production.” J. Pet. Sci. Eng. 207 (Dec): 109168. https://doi.org/10.1016/j.petrol.2021.109168.
Wang, Q., X. B. Su, Y. Jin, C. Y. Sun, S. Y. Yu, W. Z. Zhao, and Y. L. Feng. 2023a. “Experimental investigation of reservoir fluid interlayer crossflow through fracture during the drainage stage of coal measure gas well.” Nat. Resour. Res. 32 (3): 1283–1298. https://doi.org/10.1007/s11053-023-10187-3.
Wang, Q., X. B. Su, L. N. Su, H. Y. Guo, J. X. Song, and Z. L. Zhu. 2020. “Theory and application of pseudo-reservoir hydraulic stimulation for coalbed methane indirect extraction in horizontal well: Part 1—Theory.” Nat. Resour. Res. 29 (Mar): 3873–3893. https://doi.org/10.1007/s11053-020-09680-w.
Wang, Y., and S. M. Liu. 2019. “Estimation and modeling of pressure-dependent gas diffusion coefficient for coal: A fractal theory-based approach.” Fuel 253 (Oct): 588–606. https://doi.org/10.1016/j.fuel.2019.05.009.
Wang, Y. L., C. Li, Z. Li, Q. Ye, and X. Gao. 2023b. “Lost gas and desorption kinetics of coal at different pressures, exposure times, and sampling intervals.” J. Energy Eng. 149 (4): 04023015. https://doi.org/10.1061/JLEED9.EYENG-4681.
Wang, Z. M., S. Hurter, Z. J. You, V. Honari, Y. N. Sun, and S. Zhang. 2021b. “Influences of negative pressure on air-leakage of coal seam gas extraction: Laboratory and CFD-DEM simulations.” J. Pet. Sci. Eng. 196 (Jan): 107731. https://doi.org/10.1016/j.petrol.2020.107731.
Wang, Z. M., Y. N. Sun, Z. H. Li, Y. L. Wang, and Z. J. You. 2022. “Multiphysics responses of coal seam gas extraction with borehole sealed by active support sealing method and its applications.” J. Nat. Gas Sci. Eng. 100 (Apr): 104466. https://doi.org/10.1016/j.jngse.2022.104466.
Xiong, W., Q. Lei, S. S. Gao, Z. M. Hu, and H. Xue. 2009. “Pseudo threshold pressure gradient to flow for low permeability reservoirs.” Pet. Explor. Dev. 36 (2): 232–236. https://doi.org/10.1016/S1876-3804(09)60123-3.
Xu, J., L. Cheng, Y. Zhou, and L. Ma. 2007. “New method for calculating kickoff pressure gradient in low permeability reservoirs.” Pet. Explor. Dev. 34 (5): 593–594.
Yang, F., Z. F. Ning, and H. Q. Liu. 2014. “Fractal characteristics of shales from a shale gas reservoir in the Sichuan Basin, China.” Fuel 115 (1): 378–384. https://doi.org/10.1016/j.fuel.2013.07.040.
Ye, W. Z., X. Y. Wang, C. G. Cao, and W. S. Yu. 2019. “A fractal model for threshold pressure gradient of tight oil reservoirs.” J. Pet. Sci. Eng. 179 (Aug): 427–431. https://doi.org/10.1016/j.petrol.2019.04.039.
Ye, Z. H., D. Chen, and J. G. Wang. 2014. “Evaluation of the non-Darcy effect in coalbed methane production.” Fuel 121 (2): 1–10. https://doi.org/10.1016/j.fuel.2013.12.019.
Yu, S., X. Su, J. Song, Q. Wang, and Z. You. 2022. “The hole sealing technology of solid–Liquid Materials with three pluggings and two injections for gas extraction hole in the coal mine.” ACS Omega 7 (48): 43847–43855. https://doi.org/10.1021/acsomega.2c05001.
Zhang, Z., and Q. T. Hu. 2015. “Analysis Method for permeability characteristics of gas-filled coal based on considering adsorption effect.” Min. Saf. Environ. Prot. 42 (3): 98–100.
Zhao, W., Y. P. Cheng, Z. J. Pan, K. Wang, and S. M. Liu. 2019. “Gas diffusion in coal particles: A review of mathematical models and their applications.” Fuel 252 (Sep): 77–100. https://doi.org/10.1016/j.fuel.2019.04.065.
Zhou, S. 1980. “Measurement and calculation of gas permeation coefficients of coal seams.” J. China Univ. Min. Technol. (1): 4–9.
Zhou, S. N. 1990. “Mechanism of gas flow in coal seams.” J. China Coal Soc. 15 (1): 15–24.
Information & Authors
Information
Published In
Journal of Energy Engineering
Volume 149 • Issue 6 • December 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Jan 18, 2023
Accepted: Jul 20, 2023
Published online: Sep 12, 2023
Published in print: Dec 1, 2023
Discussion open until: Feb 12, 2024
ASCE Technical Topics:
- Coal
- Energy engineering
- Energy sources (by type)
- Engineering fundamentals
- Field tests
- Flow (fluid dynamics)
- Fluid dynamics
- Fluid mechanics
- Fluid velocity
- Fuels
- Gas flow
- Geomechanics
- Geotechnical engineering
- Hydrologic engineering
- Materials characterization
- Materials engineering
- Natural gas
- Non-renewable energy
- Permeability (material)
- Petroleum
- Seepage
- Soil mechanics
- Soil properties
- Tests (by type)
- Water and water resources
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.
Cited by
- Jian Wang, Mifu Zhao, Bowen Wang, Yahua Wang, Gang Yang, Tengfei Ma, Jiafang Xu, Prediction of Coal Seam Permeability by Hybrid Neural Network Prediction Model, Journal of Energy Engineering, 10.1061/JLEED9.EYENG-5358, 150, 4, (2024).
- Laigui Wang, Jian Liu, Hewan Li, Tianjiao Ren, Damage Law of Liquid Nitrogen Freeze–Thaw Action on Deep Coal Seam with Different Angle Joints, Journal of Energy Engineering, 10.1061/JLEED9.EYENG-5356, 150, 4, (2024).