Academician Melnikov Research Institute of Comprehensive Exploitation of Mineral Resources—IPKON, Russian Academy of Sciences, Moscow, Russia:

V. N. Zakharov, Director, Professor, Doctor of Engineering Sciences, Corresponding Member of the Russian Academy of Sciences
V. A. Trofimov, Head of Laboratory, Chief Researcher, Doctor of Engineering Sciences, asas_2001@mail.ru
Yu. A. Filippov, Senior Researcher, Candidate of Engineering Sciences
A. V. Shlyapin, Deputy Director, Candidate of Engineering Sciences

The problem connected with methane emission in metallic and nonmetallic mines becomes highly pressing today in view of the current surge in the mining industry. Gas emissions are often observed even in ore mines, let along coal mining where the gas criterion is the determinant of operational safety. The mechanisms and patterns of mass transfer greatly depend on the structure and properties of enclosing rock mass, as well as on the configuration of mined-out area and certain mining systems. The article presents the numerical analysis of time history of gas pressure in coal seams. The time response characteristics of gas mass transfer are studied and compared, and it is shown that desorption occurs at higher intensity than absorption, other things being equal. The conditions of abnormal absorption are found, when a naturally permeable area in a coal seam becomes impermeable, which limits gas mass transfer. The applicability of the proposed approach in interpretation of laboratory test data on permeability is illustrated. The implemented numerical modeling in combination with the experimental data have revealed some specific features of methane flow in coal, connected with cyclic gas sorption–desorption.
The study was supported by the Ministry of Science and Higher Education of the Russian Federation, Agreement No. 075-15-2021-943, and by the European Commission Research Fund for Coal and Steel (RFCS, Project: Advanced methane drainage strategy employing underground directional drilling technology for major risk prevention and greenhouse gases emission mitigation GA: 847338—DD-MET—RFCS-2018/RFCS-2018.

1. Zhang Li, Zhang Hui, Guo Hao. A case study of gas drainage to low permeability coal seam. International Journal of Mining Science and Technology. 2017. Vol. 27, Iss. 4. pp. 687–692.
2. Xiaolei Liu, Caifang Wu, Guoying Wei, Xiaodong Zhang, Tianrang Jia et al. Adsorption deformation characteristics of coal and coupling with permeability during gas injection. Journal of Petroleum Science and Engineering. 2020. Vol. 195. 107875. DOI: 10.1016/j.petrol.2020.107875
3. Junhui Wang, Zhijun Wan, Yi Wang, Zhixiang Liu, Sifei Liu et al. Effect of Stress and Moisture Content on Permeability of Gas-Saturated Raw Coal. Hindawi Geofluids. 2020. Vol. 2020. ID 8837758. DOI: 10.1155/2020/8837758
4. Shouqing Lu , Chengfeng Wang, Mingjie Li, Zhanyou Sa, Yongliang Zhang et al. Gas time-dependent diffusion in pores of deformed coal particles: Model development and analysis. Fuel. 2021. Vol. 295. 120566. DOI: 10.1016/j.fuel.2021.120566
5. Gaoming Wei, Hu Wen, Jun Deng, Li Ma, Zhenbao Li et al. Liquid CO₂ injection to enhance coalbed methane recovery: An experiment and in-situ application test. Fuel. 2021. Vol. 284. 119043. DOI: 10.1016/j.fuel.2020.119043
6. Khoa M. Tran, Ha H. Bui, Giang D. Nguyen. DEM modelling of unsaturated seepage flows through porous media. Computational Particle Mechanics. 2021. DOI: 10.1007/s40571-021-00398-x
7. Jianhua Li, Bobo Li, Zhihe Wang, Chonghong Ren, Kang Yanga et al. A permeability model for a nisotropic coal masses under different stress conditions. Journal of Petroleum Science and Engineering. 2021. Vol. 198. 108197. DOI: 10.1016/j.petrol.2020.108197
8. Chonghong Ren, Bobo Li, Jiang Xu, Yao Zhang, Jianhua Li et al. A Novel Damage-Based Permeability Model for Coal in the Compaction and Fracturing Process Under Different Temperature Conditions. Rock Mechanics and Rock Engineering. 2020. Vol. 53. pp. 56 97–5713.
9. Xuexi Chen, Liang Zhang, Maoliang Shen. Experimental research on desorption characteristics of gas-bearing coal subjected to mechanical vibration. Energy Exploration & Exploitation. 2020. Vol. 38, Iss. 5. pp. 1454–1466.
10. Ravshanov N. Numerical study of the process of non-stationary gas filtration in isothermal mode. Problemy vychislitelnoy i prikladnoy matematiki. 2021. No. 1(31). pp. 36–56.
11. Morozkin N. N. Researching the problem of nonstationary filtration of viscoplastic oil. Neftyanoe khozyaystvo. 2016. No. 6. pp. 112–114.
12. Fayziev Kh., Khozhiev T. K., Khazhiev I. O., Rakhimov Sh. Numerical solution of unsteady filtration in earth dams with considering filtration anisotropically ground finite difference method. Izvestiya vuzov. Stroitelstvo. 2017. No. 7(703). pp. 66–74.
13. Pereira Magalhaes G. Ju., Karyakin I. Yu. Modeling 2D single-phase flow of compressible fluid : A case-study of Tyumen Petroleum Research Center. Mathematical and Informational Modeling : Collection of Scientific Papers. Tyumen : Izdatelstvo Tyumenskogo gosudarstvennogo universiteta, 2017. Vol. 15, Iss. 1. pp. 287–294.
14. Zakirov E. S., Indrupskiy I. M., Anikeev D. P. Problems of numerical simulation of fields’ development using commercial simulation software. Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy. 2016. No. 6. pp. 52–58.
15. Vasilev V. I., Vasileva M. V., Nikiforov D. Ya. Solving one phase filtration problems using finite element method on computing cluster. Vestnik Severo-Vostochnogo federalnogo universiteta im. M. K. Ammasova. 2016. No. 6(56). pp. 31–40.
16. Shurina E. P., Itkina N. B., Trofimova S. A. Mathematical modelling of the filtration process in a porous medium based on non-conformal mixed finite element formulation. Vychislitelnye tekhnologii. 2020. Vol. 25, No. 5. pp. 42–54.
17. Kuznetsov S. V., Trofimov V. A. General provisions and peculiarities of gas flow in coal seams. GIAB. 2000. No. 8. pp. 79–84.
18. Zakharov V. N., Malinnikova O. N., Trofimov V. A., Filippov Yu. A. Effect of gas content and actual stresses on coalbed permeability. Journal of Mining Science. 2016. Vol. 52, Iss. 2. pp. 218–225.
19. Kuznetsov S. V., Trofimov V. A. Gas-permeable zones in coal seams and the nature and mechanism by which they form. Journal of Mining Science. 1999. Vol. 35, Iss. 1. pp. 19–25.
20. Averin A. P., Belousov F. S., Pashichev B. N., Trofimov V. A. Gas flow patterns in rock samples. GIAB. 2021. No. 10. pp. 100–111.