Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology

Wałowski, Grzegorz

doi:10.3390/en14154462

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…For instance, from the view of cavity expansion, Luo and Wang [8], Akbarzadeh and Chalaturnyk [9], Janoszek et al [10] investigated the confining rock during coal combustion, suggesting obvious changes in the mechanical properties of rock at high temperature and pore pressure. The permeability of near-field rock of a UCG cavity, as announced by Otto and Kempka [11], Wałowski [12], Madiutomo et al [13], Ding et al [14], experiences significant change during cavity expansion, while that of far-field rock is influenced to a limited degree. Meng et al [5], Duan et al [15], Jin et al [16] investigated the fracture characteristics, evolution law and influence tendency induced by pore pressure, thermal damage, etc.…”

Section: Introductionmentioning

confidence: 93%

Investigation of the Evolution of Stratum Fracture during the Cavity Expansion of Underground Coal Gasification

Dong

Zhao

et al. 2022

Energies

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The evolution of fracture zone controls the safety of underground coal gasification (UCG) in terms of gas emission and water leakage. In order to understand the fracture propagation in the confining rock of a UCG cavity with various influence factors, this paper implemented a set of numerical models based on different geological and operating conditions. Analysis was implemented on the mechanism of fracture propagation and its evolution characteristics, suggesting that (a) continuum expansion of the cavity leads a near-field fracture circle in confining rock initially, followed by the roof caving and successive propagation of shear band. (b) The key observed influence factors of fracture propagation are the grade of confining rock, overburden pressure, dimension of the cavity and gasifying pressure, the linear relationships between them, and the fracture height. Additionally, the fracture depth in the base board was mainly caused by tensile fracture. (c) A model was proposed based on the evolution of fracture height and depth in roof and base board, respectively. Validation of this model associated with orthogonal tests suggests a good capacity for predicting fracture distribution. This paper has significance in guiding the design of the gasifying operation and safety assessment of UCG cavities.

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Section: Introductionmentioning

confidence: 93%

Investigation of the Evolution of Stratum Fracture during the Cavity Expansion of Underground Coal Gasification

Dong

Zhao

et al. 2022

Energies

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“…Once there is an aquifer in the bottom of the floor, it will cause the damage field to be connected to the aquifer, resulting in a substantial waterconducting rupture zone, which will cause a water penetration accident in the floor. The engineering can be avoided by reducing the height of the combustion cavity, the length of the combustion cavity direction, increasing the protection of coal pillars, and other ways to avoid the occurrence of water gushing accident at the bottom plate [44].…”

Section: Ucg Numerical Modelingmentioning

confidence: 99%

The Layout of the Combustion Cavity and the Fracture Evolution of the Overlying Rock during the Process of Underground Coal Gasification

Wang

Ren

et al. 2022

Geofluids

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Based on the thermodynamic and elastodynamic theories, the controlling equation of temperature-stress coupling action on rocks containing random damage units is established by combining the Mogi-Coulomb damage criterion. And the numerical calculation model of combustion cavity expansion under temperature-stress coupling condition is established by using ABAQUS secondary development program. The fracture field evolution law during the expansion of the gasification cavity was studied under two conditions: perpendicular to (condition 1) and along the intermediate principal stress (condition 2). It is found that under the condition 1, the gasification cavity gradually forms a smaller fracture circle, while the surrounding rock at the floor of the gasification cavity generates a wide range of equivalent damage areas under the condition 2, which is unfavorable for practical engineering. The condition 1 deployment scheme is more practical in terms of the degree of rupture and the subsequent gasification process. The gasification cavity is obviously affected by the horizontal stress. When the horizontal stress is small, the stability of the surrounding rock is seriously damaged. It is necessary to fully consider the influence of in situ stress in the layout of the gasification cavity; at the same time, measures are added to the process to reduce the degree of rupture of the surrounding rock. The evolution law of the temperature field and rupture field of the surrounding pressure in the combustion cavity during the whole process of UCG was numerically simulated. The floor rupture zone develops gradually with the advancement of the working face of the combustion cavity, and deeper rupture zones appear in several areas, which need special attention in the engineering.

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“…This study [6] provides an overview of the systematic methods of the in situ coal gasification process. In the paper, it has been presented the model of the porous structure of coal and the gas movement taking place in the carbon matrix, which is part of the bed.…”

Section: Special Issue Articles' Short Reviewmentioning

confidence: 99%

Modeling and Control of Energy Conversion during Underground Coal Gasification Process

2022

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Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology

Cited by 6 publications

References 18 publications

Investigation of the Evolution of Stratum Fracture during the Cavity Expansion of Underground Coal Gasification

Investigation of the Evolution of Stratum Fracture during the Cavity Expansion of Underground Coal Gasification

The Layout of the Combustion Cavity and the Fracture Evolution of the Overlying Rock during the Process of Underground Coal Gasification

Modeling and Control of Energy Conversion during Underground Coal Gasification Process

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