Geomechanical properties and permeability of coals from the Foothills and Mountain regions of western Canada

Gentzis, Thomas; Deisman, Nathan; Chalaturnyk, Richard J.

doi:10.1016/j.coal.2006.02.007

Cited by 114 publications

(46 citation statements)

References 7 publications

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“…The input parameters used for the model calculations are summarized in Tables 1 and 2. All the parameters are specific for the coal sample used in this study, except for the Poisson's ratio n and the Young's modulus E Y , whose values have been taken from the literature for a coal similar to our own [Gentzis et al, 2007]. The set of parameters to be estimated consists of the coefficients C e and the C s,i accounting for changes in the porosity due to effective pressure and swelling, respectively, the absolute (unstressed sample) permeability k 0 and the mass transfer coefficients k M,i .…”

Section: Solution Proceduresmentioning

confidence: 99%

Role of adsorption and swelling on the dynamics of gas injection in coal

et al. 2009

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[1] An experimental technique is presented to perform gas injection experiments on coal cores confined by an external hydrostatic pressure, which makes use of the so-called transient step method. The experiments are intended to improve the knowledge on the different mechanisms acting during CO 2 storage in coal seams, in particular, those related to permeability. Helium, nitrogen, and carbon dioxide have been injected at pressure ranging from 10 to 80 bars and at confining pressures varying between 60 and 140 bars. The experiments with helium have been used to study the mechanical compliance of the coal core, whereas those with the adsorbing N 2 and CO 2 to study the effects of adsorption and swelling on the flow dynamics. The obtained experimental transient steps were successfully described using a mathematical model, consisting of mass balances accounting for gas flow and adsorption, and mechanical constitutive equations for the description of porosity and permeability changes during injection. A semiempirical relationship between permeability and operating pressures is validated, and the corresponding parameters have been evaluated. Results showed increase in permeability with decreasing effective pressure on the sample and, when an adsorbing gas was injected, a reduction in permeability caused by swelling, with CO 2 having a stronger effect compared to N 2 .

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Section: Solution Proceduresmentioning

confidence: 99%

Role of adsorption and swelling on the dynamics of gas injection in coal

et al. 2009

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“…In order to verify the analytical results, the same analytical method was carried out with laboratory results of the representative rock types: Indiana limestone [26], Tennessee marble [7], and Hegang granite [7]. Table 3 presents the axial strains and the rock parameters (m, s) of di erent rock types corresponding to the peak strength and residual strength.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…Cohesion c and friction angle φ at the peak and the starting point of the residual stage under di erent con ning pressures are various [26]. e paper assumes that any point in the post-peak stage is satis ed with the Mohr-Coulomb ultimate failure condition during the elastic unloading process.…”

Section: Strength Parameters (C φ) At the Peak And The Starting Poinmentioning

confidence: 99%

Study of Post‐Peak Strain Softening Mechanical Behaviour of Rock Material Based on Hoek–Brown Criterion

Lin

Cao

Wang

2018

Advances in Civil Engineering

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In order to build the post-peak strain softening model of rock, the evolution laws of rock parameters (m, s) were obtained by using the evolutionary mode of piecewise linear function regarding the maximum principle stress. Based on the nonlinear Hoek-Brown criterion, the analytical relationship of the rock strength parameters (m, s), cohesion (c), and friction angle (φ) has been developed by theoretical derivation. According to the analysis on the four different types of rock, it is found that, within the range from 0 to σ 3min , the peak hardness of the rock becomes smaller as the confining pressure increases and the degree of rock fragmentation decreases as well. e post-peak stress-strain curves obtained from the developed softening model are in good agreement with the laboratory test results under different confining pressures. In conclusion, the analytical method is reasonable, and it can predict the post-peak mechanical behaviour of rock well, which provides a new thought for the rocksoftening simulation.

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“…By testing cylindrical coal specimens with diameters between 61 and 300 mm from the BHP Coal's Moura Mine in Queensland, Australia at room temperature and under σ between 0.2 MPa to 10.0 MPa, Medhurst and Brown [5] measured ν between 0.17 and 0.43. Gentzis et al [4] tested several 37.5 mm-diameter coal specimens from the Foothills and Mountain regions of western Canada at room temperature and under σ ranging from 0.21 MPa and 14.0 MPa which resulted in ν between 0.26 and 0.48. Fluctuation of ν with temperature was reported by Glass [17], where ν value as small as 0.11 was measured at 250 °C.…”

Section: Stress-strain and Deformation Characteristics During Shear Amentioning

confidence: 99%

“…Extensive experimental studies were carried out to understand coal mechanical behavior under ambient temperature [3][4][5]. Permeability of coal to water, air, and gas at room temperature was previously studied [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Influence of High Pressure and Temperature on the Mechanical Behavior and Permeability of a Fractured Coal

Kasani

Chalaturnyk

2017

Energies

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Understanding mechanical behavior and permeability of coal at ambient and high temperature is key in optimizing high-temperature in-situ processes such as underground coal gasification. The main objectives of this study were to characterize thermal deformation, stress-strain behavior, and gas permeability of coal samples acquired from the Genesee coal mine in Central Alberta, Canada under various temperatures and confining stresses. These measurements were conducted in a high-pressure high-temperature triaxial apparatus. Initial thermal expansion of the coal was followed by contraction in both axial and lateral directions at about 140 • C. This temperature corresponds to occurrence of pyrolysis in the coal. All specimens showed brittle behavior during shear while forming complex shear planes. The specimens exhibited compressional volumetric strain responses at all temperatures. Deformation localization initiated at various stage during shearing. Specimens sheared at 200 • C showed higher peak stresses and larger axial strains compared to those tested at room temperature (24 • C). Fluctuations of permeability were observed with confining stress and temperature. Permeability dropped at 80 • C due to thermal expansion of coal and closure of initial fractures; however, it increased at 140 and 200 • C due to a combined response of thermal expansion and pyrolysis. Small axial strain during shear was observed to reduce permeability.

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Geomechanical properties and permeability of coals from the Foothills and Mountain regions of western Canada

Cited by 114 publications

References 7 publications

Role of adsorption and swelling on the dynamics of gas injection in coal

Role of adsorption and swelling on the dynamics of gas injection in coal

Study of Post‐Peak Strain Softening Mechanical Behaviour of Rock Material Based on Hoek–Brown Criterion

Influence of High Pressure and Temperature on the Mechanical Behavior and Permeability of a Fractured Coal

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