Pore characteristics of Wilcox Group Coal, U.S. Gulf Coast Region: Implications for the occurrence of coalbed gas

Swanson, Sharon M.; Mastalerz, María; Engle, Mark A.; Valentine, Brett J.; Warwick, Peter D.; Hackley, Paul C.; Belkin, Harvey E.

doi:10.1016/j.coal.2014.07.012

Cited by 42 publications

(11 citation statements)

References 49 publications

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“…The ash yields on an air-dried basis of the samples change greatly, ranging from 9.82 to 64.76%, with an average of 59.15% in the carbonaceous mudstones and 19.44% in the coals (Table ). As the pore and fracture in the samples can be partially filled with the ash dominated by various minerals, , ash yield is negatively correlated with porosity (Figure a). Furthermore, coals with high ash yields can effectively increase densities (Table ).…”

Section: Resultsmentioning

confidence: 99%

Correlating Coal Petrology and Methane Adsorption Parameters of High-Volatile Bituminous Coals with P-Wave Velocity

et al. 2022

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The parameters of coal petrology and methane adsorption are significant to exploit coal and coalbed methane (CBM). Based on borehole core sampling, a new method using the P-wave velocity to predict coal maceral, coal face index, and Langmuir parameter of high-volatile bituminous coals was proposed. The results showed that the P-wave velocity correlated positively with coal skeletal density, apparent density, and ash yield with fitting coefficients (R 2 ) of 0.55, 0.57, and 0.57, respectively, but it negatively correlated with coal porosity and moisture content with R 2 of 0.56 and 0.60, respectively. Vitrinite, ranging from 14.8 to 82.7% with an average of 53.8%, positively correlated with coal porosity due to more micropores in vitrinite and thus negatively correlated with the density and P-wave velocity. Inertinite content was in the range of 5.4 to 27.4% with an average of 11.0%, which correlated negatively with the coal porosity and thus positively with the density and P-wave velocity for most of the samples. Furthermore, the P-wave velocity was weakly positively correlated with mineral content, and a negative correlation was found between the P-wave velocity and vitrinite/ inertinite ratio (V/I), gelification index (GI), and Langmuir volume (V L ). The porosity (Y 1 ), vitrinite content (Y 2 ), inertinite content (Y 3 ), and V L (Y 4 ) of coals could be predicted based on the equations as follows: Y 1 = 7842.4 e −0.003X , Y 2 = −0.0003X 2 + 1.0731X − 924.09, Y 3 = 0.0003X 2 − 1.2797X + 1405, and Y 4 = −0.04X + 101.24, where X is the P-wave velocity. Generally, P-wave velocity could be largely used to predict the variations of the coal maceral and methane adsorption capacity of high-volatile bituminous coals, providing a new and valuable approach for CBM exploration and gas prevention in coal mines.

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Section: Resultsmentioning

confidence: 99%

Correlating Coal Petrology and Methane Adsorption Parameters of High-Volatile Bituminous Coals with P-Wave Velocity

et al. 2022

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“…Thus, it can be concluded that the minimum variation in pore radius is 10 nm under this investigated condition. A huge volume of gas in coal is adsorbed on the surface of micropores and minipores (Liu et al, 2015a;Swanson et al, 2014). Thus, micropores and minipores are the main factors influencing coal adsorption capacity.…”

Section: Variation In Proportions Of Pore Characteristics With Varyinmentioning

confidence: 99%

“…The authors noted a strong positive relationship between coalbed gas content and micropore volume. Swanson et al (2014) reported that the micropore surface area and micropore volume played a crucial role in the gas-holding capacity of Louisiana coal, and that adsorption through micropores is the primary form of gas storage. Both coalbed gas content and initial gas desorption velocity were examined by Jiang et al (2011a), Xu et al (2014) and Zhang et al (2015) to analyse the variations in coal subjected to the sill intrusion and its implication for abnormal gas occurrence.…”

Section: Introductionmentioning

confidence: 99%

Variations in coalbed gas content, initial gas desorption property and coal strength after drilling-slotting integration technique and gas drainage: insight into pore characteristics

Zou

Lin

Liu

et al. 2017

IJOGCT

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In this paper, the variations in coalbed gas content, initial gas desorption property and coal strength after drilling-slotting integration technique and gas drainage were investigated by testing seven coal samples obtained from the coal seam #10 of Yangliu Coal Mine. The MICP and N 2 GA were combined to characterise the pore-size distribution. It is revealed that the residual coalbed gas content decreases substantially with the decrease in boreholes distances. Nevertheless, the variations in initial gas desorption velocity and coal hardiness coefficient represent an opposite tendency. In the microscopic aspect, the variation in pore-size distribution is notable. With the decrease in the boreholes distances, the adsorption pore proportion decreases and the seepage pore proportion increases. The drilling-slotting integration technique and gas drainage affect the aforementioned three macroscopic indices by changing the pore characteristics and moisture content. Besides, the guiding significance for field application of this technique is elaborated.

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“…Previous studies have demonstrated the complex porosity system in coal. It is primarily influenced by coal rank, depth, organic matter, mineral composition, moisture, and reservoir temperature–pressure conditions. − The coal system possesses two different kinds of porosity: primary porosity, which is composed of meso- and micropores associated to the coal matrix, and secondary porosity, which is composed of fractures and cleats. − Pores are classified into three types based on size: (a) micropore- with a diameter < 2 nm, (b) mesopore- with a diameter between 2 and 50 nm, and (c) macropore with a diameter > 50 nm (IUPAC classification). Other pore categorization techniques were published by Mays, but they were not well received for coal reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Systematic Pore Characterization of Sub-Bituminous Coal from Sohagpur Coalfield, Central India Using Gas Adsorption Coupled with X-ray Scattering and High-Resolution Imaging

Bhapkar,

Pradhan,

Chandra

et al. 2023

Energy Fuels

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Pore characterization helps to estimate the coalbed methane recovery and carbon storage potential of the reservoir. Earlier research on the characteristics of coal pores has shown that coal has high hydrocarbon storage potential in the adsorbed state, but few studies have shown the influence of chemical heterogeneities and depth on the adsorption potential of the coal. With the objective of studying the effect of chemical variation, depth, and surface roughness on gas adsorption potential, this study combines coal composition analysis and adsorption-based pore characterization of coal and shale samples coupled with high-resolution imaging and X-ray scattering measurements. Variation in pore features is correlated with varying depth and composition. A decrease in the mesopore volume and surface area is observed with an increase in the depth and total organic content and inverse behavior is observed for micropores. Scanning electron microscopy images depict the change in the pore shape from semi-spherical OM pores to elongated pores with depth, and samples with high mineral content show a dominance of inter- and intraparticle pores. Fractal dimension values estimated from SAXS are notably higher than N2-LPGA-derived values (i.e.,D S > D N ) due to the incorporation of inaccessible pores, which reflects an increase of up to 62% in SAXS estimated mesopore volume and surface area. This study will provide a better approach to understand the impact of composition, depth, and surface roughness over the gas storage potential in coal reservoirs.

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Pore characteristics of Wilcox Group Coal, U.S. Gulf Coast Region: Implications for the occurrence of coalbed gas

Cited by 42 publications

References 49 publications

Correlating Coal Petrology and Methane Adsorption Parameters of High-Volatile Bituminous Coals with P-Wave Velocity

Correlating Coal Petrology and Methane Adsorption Parameters of High-Volatile Bituminous Coals with P-Wave Velocity

Variations in coalbed gas content, initial gas desorption property and coal strength after drilling-slotting integration technique and gas drainage: insight into pore characteristics

Systematic Pore Characterization of Sub-Bituminous Coal from Sohagpur Coalfield, Central India Using Gas Adsorption Coupled with X-ray Scattering and High-Resolution Imaging

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