Experiment of dynamic property and transient magnetic effects of coal during deformation and fracture

Li, Chengwu; Wei, Shanyang; Liu, Jikun; Lei, Dongji

doi:10.1007/s12404-012-0306-6

Cited by 5 publications

(6 citation statements)

References 2 publications

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“…This suggests that the agglomeration of coal fine and the hydration expansion of the clay mineral further aggravate the flow rate sensitivity of the reservoir, leading to a further reduction in permeability (Figures [18][19][20]. The above conclusion is the same as that in Reference [43]. Under the conditions of NaHCO 3 solution displacement, the mass concentration of coal fine production decreases with the decrease in salinity degree.…”

Section: Changes In Macro-micro Physical Properties Of Coal Reservoir...supporting

confidence: 53%

“…With the increase in salinity, the anion OHgenerated by hydrolysis increases the surface negative charge of coal fine and enhances the repulsion force between coal fine particles. Coal fine is easy to disperse and not conducive to agglomeration [43]. Under the condition of high salinity, a large amount of coal fine is suspended, which also explains that with the increase in salinity, the decrease in water sensitivity and the weakening of agglomeration effects of coal fine, resulting in a more significant trend of increasing micropore content with the increase in flow velocity.…”

Section: Response Mechanism Of Coal Fine Migration-induced Reservoir ...mentioning

confidence: 99%

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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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Section: Changes In Macro-micro Physical Properties Of Coal Reservoir...supporting

confidence: 53%

Section: Response Mechanism Of Coal Fine Migration-induced Reservoir ...mentioning

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 acting duratio of high pressure gas on the coal body due to expansion inside the borehole is at least orders of magnitude over that of the stress wave. Because the pressure of high pressure gas is relatively stable, the action process can be deemed as a quasi-static process [11]. The stress intensity factor, K I , of the macro fractures under the effect of high pressure gas is expressed:…”

Section: S696mentioning

confidence: 99%

Numerical modeling of liquid CO2 phase transition blasting based on smoothed particle hydrodynamics algorithm

Yang

Zhou

et al. 2019

THERM SCI

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Liquid CO 2 phase transition blasting is a physical blasting method to enhance permeability through liquid CO 2 phase transition expansion. To study the propagation criterion of fractures during blasting, the energy of phase transition blasting is evaluated through the thermodynamic equation by studying the action process of the liquid CO 2 blasting, thus obtaining the scope of the smash zone and crack zone as well as the propagation criterion of fractures under the effect of high pressure gas. The gas blasting model for a coal body is established based on the SPH algorithm, thus obtaining the criteria for formation of the smash zone and for generatio and propagation of the crack zone. Moreover, the radius of phase transition blasting is surveyed onsite by the peephole method. It is shown that the explosive energy of the MZL-51/2000 phase transition blasting equipment with a release pressure of 270 MPa is 1510 kJ. The coal body is crushed by the high pressure CO 2 percussive drilling, forming the smash zone. Meanwhile, fractures are generated around the smash zone. With the expansion and migratio of the gas, the fracture will further grow into a crack zone. The fracture inside the coal body goes through four states: rapid, slow, rapid, and then slow again. According to field surveys, the blasting radius of the MZL-51/2000 equipment with loaded liquid of 1.8 kg is approximately 3 m.

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“…15,[33][34][35][36][37][38][39][40][41][42][43][44][45] Very high loading rate dynamic tests are usually conducted by using split Hopkinson pressure bar (SHPB) systems, 30,46 to determine dynamic properties of brittle materials including concretes, ceramics, rocks, and coals under wide range of impact loadings or strain rates of 10 1 -10 4 /s. [47][48][49][50][51][52][53] For determination of dynamic properties of different coals, the principal attributes are to recovery the dynamic magnitudes of Young's modulus and compressive/tensile strength based on the stress-strain curves at very high strain rates. 43,45 For instance, scholars have investigated the stress-strain curves and energy dissipation of coals under different bedding orientations, dry or saturated coals.…”

Section: Introductionmentioning

confidence: 99%

“…Dynamic properties of interest include the following: density, wave velocity, porosity, strength, scale effect, bedding effect, the influence of moisture, and energy dissipation . Very high loading rate dynamic tests are usually conducted by using split Hopkinson pressure bar (SHPB) systems, to determine dynamic properties of brittle materials including concretes, ceramics, rocks, and coals under wide range of impact loadings or strain rates of 10 1 ‐10 4 /s . For determination of dynamic properties of different coals, the principal attributes are to recovery the dynamic magnitudes of Young's modulus and compressive/tensile strength based on the stress‐strain curves at very high strain rates .…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

110

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We report laboratory experiments to investigate the dynamic failure characteristics of outburst‐prone coal using a split Hopkinson pressure bar (SHPB). For comparison, two groups of experiments are completed on contrasting coals—the first outburst‐prone and the second outburst‐resistant. The dynamic mechanical properties, failure processes, and energy dissipation of both outburst‐prone and outburst‐resistant coals are comparatively analyzed according to the obtained dynamic compressive and tensile stress‐strain curves. Results show that the dynamic stress‐strain response of both outburst‐prone and outburst‐resistant coal specimens comprises stages of compression, linear elastic deformation, then microfracture evolution, followed by unstable fracture propagation culminating in rapid unloading. The mechanical properties of both outburst‐prone and outburst‐resistant coal specimens exhibit similar features: The uniaxial compressive strength and indirect tensile strength increase linearly with the applied strain rate, and the peak strain increases nonlinearly with the strain rate, whereas the elastic modulus does not exhibit any clear strain rate dependency. Differences in the dynamic failure characteristics between outburst‐prone and outburst‐resistant coals also exist. The hardening effect of strain rate on outburst‐prone coal is more apparent than on outburst‐resistant coal, which is reflected in the dynamic increase factor at the same strain rate. However, the dynamic strength of outburst‐prone coals is still lower than that of outburst‐resistant coals due to its low quasi‐static strength. The dissipated energy of outburst‐prone coal is smaller than that of outburst‐resistant coal. Therefore, the outburst‐prone coal, characterized by low strength, high deformability, and small energy dissipation when dynamically loaded to failure, is more favorably disposed to the triggering and propagation of gas outbursts.

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Experiment of dynamic property and transient magnetic effects of coal during deformation and fracture

Cited by 5 publications

References 2 publications

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

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

Numerical modeling of liquid CO2 phase transition blasting based on smoothed particle hydrodynamics algorithm

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

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