Experimental study on permeability stress sensitivity of reconstituted granular coal with different lithotypes

Geng, Yunguang; Tang, Dazhen; Xu, Hao; Tao, Shu; Tang, Shuling; Ma, Linjian; Zhu, Xueguang

doi:10.1016/j.fuel.2017.03.093

Cited by 82 publications

(34 citation statements)

References 35 publications

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“…CBM is different from conventional gases and mainly resides in coal reservoirs due to adsorption. As a special organic rock mass, coalbeds are typically characterized by low mechanical strength, cleat development, and strong heterogeneity (Geng et al, 2017). Coal reservoirs have significant sensitivity for temperature, pressure, and stress, which results in the evident planar zonation and vertical leap variations in CBM accumulation and development conditions (Clarkson et al, 2011;George and Barakat, 2001;Li et al, 2014;White, 2005;Yao and Liu, 2012).…”

Section: Introductionmentioning

confidence: 99%

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

Guo

Xia

et al. 2019

Energy Exploration & Exploitation

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The Hancheng area is a hot spot for coalbed methane exploration and exploitation in China. Structure is a key factor affecting coalbed methane accumulation and production in the Hancheng area. For a better understanding of the coalbed methane accumulation conditions and high-yield potential, this study investigates the structural patterns and evolution, the hydrogeological conditions, and the geothermal field in the coal-bearing strata in the Hancheng area. Then, the spatial distribution of the coalbed methane content and the tectonic deformation of the coal seam are evaluated. Finally, the critical depth for coalbed methane enrichment and a high-yield

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Section: Introductionmentioning

confidence: 99%

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

Guo

Xia

et al. 2019

Energy Exploration & Exploitation

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“…Wang et al 18 investigated the deformation and gas flow characteristics of coal-like materials under triaxial stress conditions. Geng et al 19 24 performed adsorption and desorption tests and full stress-strain-seepage tests on samples in layers with different dip angles. Yu et al 25 studied the effects of confining pressure, axial pressure and temperature on the permeability of shaped coal samples.…”

Section: Introductionmentioning

confidence: 99%

“…Zakharow et al 15 put forward an analytical relation between coal permeability, stresses, and adsorbed gas to define parameters of gas leakage zone parameters and laws of mass transfer. Geng et al 19 used reconstituted coal as a research material to study porosity and permeability characteristics of compacted coal fines in coal reservoir fractures. Zuo et al 17 determined the effective stress coefficient of coal during gas penetration and investigated the impact of effective stress and gas slippage on coal permeability under cyclic loading conditions.…”

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confidence: 99%

Test and analysis of mechanics and permeation properties of raw coal

Yang

Zhang

et al. 2019

Energy Science & Engineering

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In this paper, we investigated the mechanics and permeation properties of the raw coal sample during loading and unloading process, and come to some conclusions: the permeability of the sample increases nonlinearly during the unloading confining pressure process. The larger the gas pressure is, the greater the increase range of the permeability will be. The larger the confining pressure unloading amplitude is, the greater the increase range of the permeability will be. In the loading process, the permeability and the axial strain of the specimen change in a “V” shape. As the gas pressure increases, the peak strength of the specimen gradually decreases, and fitted the gas pressure and the peak strength are accordance with the linear relationship. As the confining pressure increase, the peak strength of the sample gradually increases, and fitted the confining pressure and the peak strength are accordance with the exponential function. The internal friction angle of the coal sample was 43.22°, and the cohesion was 3.77 MPa. The relationship between the fitted gas pressure and internal friction angle, gas pressure and cohesion is in line with linear functions. Maintain an axial stress constant, unloaded confining pressure to a constant state of target value, the permeability of specimen shows a constant pressure boosting flow zone, the relationship between permeability and deviatoric stress is accordance with the ExpDec1 function during the process of unloading confining pressure and prepeak loading axial stress.

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“…During coalbed methane (CBM) exploration and development, the reservoir petrophysical properties, particularly the permeability, are crucial for potential and productivity evaluation of CBM resources . The low‐permeability characteristic of coal reservoirs in China requires reservoir stimulation during CBM exploitation.…”

Section: Introductionmentioning

confidence: 99%

Postfracturing permeability prediction for CBM well with the analysis of fracturing pressure decline

Zhang

Wang

et al. 2019

Energy Science & Engineering

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Hydraulic fracturing is a widely used reservoir stimulation technique to exploit CBM in China. Compared with the original permeability of coal reservoir, the postfracturing permeability is more critical for the productivity evaluation of CBM wells. Based on hydraulic fracturing, microseismics monitoring, and well test data of the CBM wells in Zhengzhuang block of Qinshui Basin, this paper proposes a simple method to obtain the fitting pressure by the classic fracturing pressure decline analysis theory under the condition of corrected dynamic overall leakoff coefficient. In addition, the postfracturing permeability of coal reservoir is predicted by the injection well testing theory. The morphology of hydraulic fractures in the study area is mainly determined by in‐situ stress, and most fractures are vertical ones propagating along the direction of the maximum principal stress. The fracturing curves of the study area can be classified into stable curves, stably fluctuating curves, descending curves, ascending curves, and fluctuating curves, where the stable and descending fracturing curves represent better fracturing effect. The length of hydraulic fractures is much greater than the height. The PKN model has been selected as the hydraulic fracture propagation model to analyze the fracturing pressure decline. The slope value of liner segment of G(δ,0) curve is proposed as the criterion for the fitting pressure calculation. The postfracturing permeabilities of coal reservoir range from 1.55 to 8.83 × 10−3 μm2, all of which are remarkably higher than that of the original reservoir.

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Experimental study on permeability stress sensitivity of reconstituted granular coal with different lithotypes

Cited by 82 publications

References 35 publications

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

Geological conditions of coalbed methane accumulation in the Hancheng area, southeastern Ordos Basin, China: Implications for coalbed methane high-yield potential

Test and analysis of mechanics and permeation properties of raw coal

Postfracturing permeability prediction for CBM well with the analysis of fracturing pressure decline

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