Mechanical behavior of low-rank bituminous coal under compression: An experimental and numerical study

Liu, Yanfei; Li, Song; Tang, Dazhen; Tao, Shu; Xiong, Hu; Zhu, Xueguang; Ma, Linjian

doi:10.1016/j.jngse.2019.03.012

Cited by 10 publications

(3 citation statements)

References 42 publications

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“…It shows that under the condition of reasonable confining pressure and moisture content, it is beneficial to the transformation of water-bearing coal from brittleness to ductility and to the release of energy. Literature [42] also supports our views to some extent. In the process of coal mining, the horizontal stress from three-way hydrostatic state will gradually be low to 0 from coal seam depth to the working face.…”

Section: Results and Analysissupporting

confidence: 87%

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

et al. 2021

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Coal seam water injection is an important technical method to prevent and control coal and gas outburst and other disasters. Water can soften coal and change its mechanical properties. In order to study the mechanical properties of coal samples with different moisture content, briquette coal samples with five moistures content (4%, 6%, 8%, 10%, and 12%) were selected to carry out triaxial compression tests under different confining pressures (0.1, 0.2, 0.4, 0.8, and 1.2 MPa). Then, the mechanical response mechanism of the water-bearing briquette coal was analyzed. The results show that the slope of the linear elastic stage of the stress-strain curve gradually decreases with the increase of moisture content. Water-bearing coal exhibits strain strengthening characteristics under high confining pressure, which transforms the water-bearing coal from brittle to ductile state. The peak stress under different moisture content conditions shows a linear relationship with the confining pressure. The internal friction angle decreases linearly with the increase of moisture content. The cohesion varies parabolically with the increase of moisture content and reaches the maximum value when the moisture content is 8%. The coal body with moisture content between 7% and 9% has a high bonding force, which is beneficial to the consolidation of the coal body. Therefore, ensuring a reasonable moisture content of coal through coal seam injection can provide a basis for preventing coal and gas outburst.

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Section: Results and Analysissupporting

confidence: 87%

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

et al. 2021

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“…The main structure of the Baode Block is relatively simple. In general, it is a large monoclinal structure inclined to the NW with no developed faults and folds [29,30]. The groundwater in the study area mainly comes from atmospheric precipitation and the lateral recharge of Ordovician limestone, with runoff generally flowing from east to west.…”

Section: Geological Backgroundmentioning

confidence: 99%

Response and Mechanism of Coal Fine Production to Differential Fluid Action in the Baode Block, Ordos Basin

Wang,

Cui,

et al. 2023

Processes

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The Baode Block in the Ordos Basin is currently one of the most successfully developed and largest gas field of low–medium rank coal in China. However, the production of coal fine has affected the continuous and stable drainage and efficient development of this area. The special response and mechanism of differential fluid action during the drainage process is one of the scientific issues that must be faced to solve this production problem. In view of this, the evolution laws of a reservoir’s macro–micro physical characteristics under different fluid conditions (fluid pressure, salinity) have been revealed, and the response mechanism of coal fine migration-induced reservoir damage has been elucidated through a nuclear magnetic resonance online displacement system. The results indicated that pores at different scales exhibited varying patterns with increasing displacement pressure. The proportion of the mesopore and transition pore is not affected by salinity and is positively correlated with displacement pressure. When the salinity is between 3000 mg/L and 8000 mg/L, the proportion of macropore and micropore showed parabolic changes with increasing displacement pressure, and there was a lowest point. The evolution law of pore fractal dimension and permeability change rate under the action of different fluids jointly showed that there was an optimal salinity for the strongest reservoir sensitivity enhancement effect. The mechanical and chemical effects of fluid together determined the damage degree of coal reservoir induced by coal fine migration.

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“…The low-field nuclear magnetic resonance (LF-NMR) technique has the advantages of no disturbance to samples, accurate detection, and high resolution and can quantitatively identify the hydrogen nuclei content in water. It has been widely used to study pore–fracture structure characterization, morphology, size, and porosity. − Subsequently, many scholars focus on methane and propose a calibration method of quantitatively characterizing methane content of different phases using NMR. This provides an idea for studying real-time methane desorption–diffusion during CBM extraction .…”

Section: Introductionmentioning

confidence: 99%

Review on the Application of Low-Field Nuclear Magnetic Resonance Technology in Coalbed Methane Production Simulation

et al. 2022

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Low-field nuclear magnetic resonance has become one of the main methods to characterize static parameters and dynamic changes in unconventional reservoirs. The research focus of this paper is process simulation of coalbed methane (CBM) production. The dynamic variation of pore volume with different pore sizes during pressure drop, methane desorption–diffusion process, and methane–water interaction during migration is discussed. Moreover, the calculation principles of NMR single and multifractal models are systematically described, and the applicability of NMR fractal models within different research contexts is discussed. Four aspects need urgent attention in the application of this technology in CBM production: (1) overburden NMR technology has limitations in characterizing the stress sensitivity of shale and high-rank coal reservoirs with micropores developed, and we should aim to enable an accurate description of micropore pore stress sensitivity; (2) dynamic NMR physical simulation of reservoir gas and water production based on in-situ and actual geological development conditions should become one of the key aspects of follow-up research; (3) low-temperature freeze–thaw NMR technology, as a new pore–fracture characterization method, needs to be further applied in characterizing the distribution characteristics of pores and fractures; and (4) NMR fractal model should be used as the main theoretical method to expand the simulation results. The applicability of different fractal models in characterizing pore–fracture structure (static) and CBM production process (dynamic) needs to be clarified.

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Mechanical behavior of low-rank bituminous coal under compression: An experimental and numerical study

Cited by 10 publications

References 42 publications

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

Response and Mechanism of Coal Fine Production to Differential Fluid Action in the Baode Block, Ordos Basin

Review on the Application of Low-Field Nuclear Magnetic Resonance Technology in Coalbed Methane Production Simulation

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