The dynamic behaviour of coal relative permeability curves

Shaw, Dylan; Mostaghimi, Peyman; Armstrong, Ryan T.

doi:10.1016/j.fuel.2019.04.107

Cited by 36 publications

(16 citation statements)

References 35 publications

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“…Power-law models are frequently used to represent relative permeability in history matches due to the small number of tunable parameters. Although Shawn et al [27] suggest that the simple modified Brooks-Corey-type model [46] is adequate in representing gas and water relative permeability curves of coals, we adopt Chen et al's model [2] in this study, which is more versatile than the Brooks-Corey model. Chen et al's relative permeability model is developed specifically for coals and incorporates both the match-stick geometry of cleats and its effect on the computation of the capillary pressure.…”

Section: Representation Of Relative Permeability and Capillary Pressurementioning

confidence: 99%

“…However, it is usually difficult to define the proper values without knowledge of the capillary pressure characteristics in real laboratory tests. To the best knowledge of the authors, experimental data on capillary pressure for gas-liquid-coal systems at high pore pressures and under confined conditions are still lacking due to the difficulty in making such measurements [27]. As such, it is of practical significance to estimate relative permeability and capillary pressure simultaneously from an individual unsteady-state displacement test to eliminate the difficulty of capillary pressure measurement.…”

Section: Representation Of Relative Permeability and Capillary Pressurementioning

confidence: 99%

“…The assisted history matching method has been successfully used to derive water/oil relative permeability curves from core-flooding tests [24][25][26]. Shaw et al [27] used manual history matching to simultaneously derive relative permeability and capillary pressure for gas-water-coal systems. However, to the best knowledge of the authors, no publication has ever reported the application of assisted history matching in deriving the relative permeability (RP) from core-flooding tests for a gas/liquid system.…”

Section: Introductionmentioning

confidence: 99%

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Interpretation of Gas/Water Relative Permeability of Coal Using the Hybrid Bayesian-Assisted History Matching: New Insights

Zhang

et al. 2021

Energies

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The relative permeability of coal to gas and water exerts a profound influence on fluid transport in coal seams in both primary and enhanced coalbed methane (ECBM) recovery processes where multiphase flow occurs. Unsteady-state core-flooding tests interpreted by the Johnson–Bossler–Naumann (JBN) method are commonly used to obtain the relative permeability of coal. However, the JBN method fails to capture multiple gas–water–coal interaction mechanisms, which inevitably results in inaccurate estimations of relative permeability. This paper proposes an improved assisted history matching framework using the Bayesian adaptive direct search (BADS) algorithm to interpret the relative permeability of coal from unsteady-state flooding test data. The validation results show that the BADS algorithm is significantly faster than previous algorithms in terms of convergence speed. The proposed method can accurately reproduce the true relative permeability curves without a presumption of the endpoint saturations given a small end-effect number of <0.56. As a comparison, the routine JBN method produces abnormal interpretation results (with the estimated connate water saturation ≈33% higher than and the endpoint water/gas relative permeability only ≈0.02 of the true value) under comparable conditions. The proposed framework is a promising computationally effective alternative to the JBN method to accurately derive relative permeability relations for gas–water–coal systems with multiple fluid–rock interaction mechanisms.

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Section: Representation Of Relative Permeability and Capillary Pressurementioning

confidence: 99%

Section: Representation Of Relative Permeability and Capillary Pressurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Interpretation of Gas/Water Relative Permeability of Coal Using the Hybrid Bayesian-Assisted History Matching: New Insights

Zhang

et al. 2021

Energies

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“…However, with increasing mining depth, the gas pressure of the coal seam increases and the permeability decreases, which seriously affects the gas predrainage effect 7 – 9 . In engineering practice, the deep hole presplitting blasting permeability increasing technology can produce multiple cracks in the coal body of a low permeability coal seam, forming an underground fracture network channel, which can greatly improve the gas drainage efficiency and reduce or even eliminate the hidden dangers in the gas mining process 10 – 13 .…”

Section: Introductionmentioning

confidence: 99%

Study on the technology of enhancing permeability by deep hole presplitting blasting in Sanyuan coal mine

Zhao

Wang

Gao

2021

Sci Rep

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To reduce gas disasters in low permeability and high gas coal seams and improve gas predrainage efficiency, conventional deep hole presplitting blasting permeability increasing technology was refined and perfected. The damage degree of coal and rock blasting was quantitatively evaluated by using the value range of the damage variable D. According to the actual field test parameters of coal seam #3 in the Sanyuan coal mine, Dlim = 0.81 ~ 1.0 was the coal rock crushing area, Dlim = 0.19 ~ 0.81 was the coal rock crack area, and Dlim = 0 ~ 0.19 was the coal rock disturbance area. The blasting models under different blasting parameters were established by ANSYS/LS-DYNA software. The influence radius of single-hole blasting was 3.1 m, the hole diameter of double-hole blasting was 113 mm, the hole spacing was 5.5 m, and the delayed blasting time was 25 ms. According to the numerical simulation results, the determined parameters were tested on the working face of the 1312 transportation roadway in coal seam #3 of the Sanyuan coal mine. The results show that after blasting, the permeability of the original coal seam was increased by more than 30 times, the gas concentration was increased by 2.16 times, and the single hole purity and mixing volume were increased by 4.73 and 4.27 times, respectively. The positive effects of deep hole presplitting blasting permeability enhancement technology on the pressure relief and permeability enhancement of a low pressure and high gas coal seam were determined.

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“…Chen et al [18] modified the classical SD permeability model by considering the competitive adsorption effect of gas and moisture and established a solid-gas-liquid coupling model. Shaw et al [19] studied the relative permeability during coal seam gas production.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Influence of Moisture Content during Gas Depressurization Extraction

Chen

et al. 2019

Advances in Materials Science and Engineering

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Although there are many reports about the influence of moisture in the process of gas extraction, studies about the influence of moisture on gas flow, permeability, and coal deformation by experimental system analysis are lacking. Physical simulations of gas depressurization extraction using triaxial servo-controlled seepage equipment for hot-fluid-solid coupling were conducted. The gas flow rate, permeability, and strain were analysed during gas depressurization extraction. The relationship between gas flow rate and gas pressure was a quadratic polynomial. Permeability and strain changed continuously with the decrease of gas pressure and interacted with each other during gas depressurization extraction. In the initial stage, the effective permeability decreased. With the continuous decrease of gas pressure, the permeability gradually recovered. When the gas pressure dropped to about 0.6 MPa, the permeability increased rapidly and the corresponding volumetric strain increased gradually. With the increase of moisture content, the relationship between gas flow rate and gas pressure became less significant. The experiments showed that the higher the moisture content, the lower the effective permeability and the larger the volumetric strain.

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The dynamic behaviour of coal relative permeability curves

Cited by 36 publications

References 35 publications

Interpretation of Gas/Water Relative Permeability of Coal Using the Hybrid Bayesian-Assisted History Matching: New Insights

Interpretation of Gas/Water Relative Permeability of Coal Using the Hybrid Bayesian-Assisted History Matching: New Insights

Study on the technology of enhancing permeability by deep hole presplitting blasting in Sanyuan coal mine

Experimental Study on the Influence of Moisture Content during Gas Depressurization Extraction

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