Prediction of Critical Desorption Pressure of Coalbed Methane in Multi-coal Seams Reservoir of Medium and High Coal Rank: A Case Study of Eastern Yunnan and Western Guizhou, China

Li, Cunlei; Yang, Zhaobiao; Chen, Jie; Sun, Haixin

doi:10.1007/s11053-022-10034-x

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…On the one hand, as the coal adsorbs methane, it causes the coal matrix to expand, and the expansion further narrows the pore channels of these pores. On the other hand, the complex surface corresponds to a more dynamic system, which leads to an increase in the number of available adsorption points and adsorption potential. − The desorption efficiency is generally measured in terms of the theoretical desorption rate and the recovery factor. The theoretical desorption rate and recovery factor of durain are negatively correlated with the fractal dimension Ds, indicating that the more rougher and more complex the pore surface, the lower the desorption efficiency.…”

Section: Resultsmentioning

confidence: 99%

Pore Fractal Characteristics of Different Macro-Coal Components and Influence on Adsorption/Desorption: A Case Study in the Huanglong Jurassic Coalfield

Chen

et al. 2022

ACS Omega

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The heterogeneity of pore structure in coal reservoir is extremely complex. In this paper, mercury intrusion porosimetry (MIP) and liquid nitrogen adsorption (LNA) were used to describe pore characteristics of macro-coal components, and the fractal characteristics of pores and their relationship with adsorption and desorption were discussed. The findings revealed that there were obvious differences in pore characteristics of different macro-coal components at different pore sizes. The total pore volume of vitrain and durain was equivalent, and the total specific surface area was larger than durain, indicating that the micropores in vitrain were more developed, while the macropores in durain were more developed, indicating that the specific surface area was smaller. Fractal results indicated that the pore structure of coal was more complex with the increase of pore diameter. The Da1 and Da2 of vitrain and durain were affected by larger specific surface area and pore volume. The Ds of vitrain increased first and then decreased with the content of vitrinite, while that of durain was the opposite. The relationship between the adsorption capacity of vitrain and fractal dimension Da1 was binomial distribution, and it was positively correlated with Da2. The adsorption capacity of durain samples increased first and then decreased with Da1. With the increase of fractal dimension Ds, the theoretical desorption rate and recovery rate of durain had a downward trend, that is, the more complex the pore structure, the poor the desorption efficiency.

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Section: Resultsmentioning

confidence: 99%

Pore Fractal Characteristics of Different Macro-Coal Components and Influence on Adsorption/Desorption: A Case Study in the Huanglong Jurassic Coalfield

Chen

et al. 2022

ACS Omega

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“…The gas saturation of coal seams reflects the degree of resource enrichment. The critical desorption pressure is commonly used to describe the release capacity of coalbed methane [24][25][26][27][28].…”

Section: Gas Enrichment Factorsmentioning

confidence: 99%

Analysis of Coalbed Methane Production Characteristics and Influencing Factors of No. 15 Coal Seam in the Shouyang Block

Zhang,

Li,

Wang

et al. 2023

Processes

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Based on the basic geological data and production data of coalbed methane wells in the Shouyang Block, the characteristics and influencing factors of coalbed methane well production were analyzed, and the primary controlling factors were identified by the grey correlation method. The results show that the average daily gas production of the coalbed methane wells in the study area for the single mining of No. 15 coal ranges from 0 to 604.34 m3/d, with an average of 116.82 m3/d. The overall average gas production is relatively low, with only 7 of the 42 wells having an average gas production greater than 200 m3/d. Gas production tends to increase as the gas content increases. There is a significant positive correlation between gas saturation and average gas production. Burial depth and coal seam thickness also show a positive correlation with average gas production. On the other hand, there is a negative exponential relationship between average gas production and critical desorption pressure. Permeability, as determined by well tests in the area, exhibits a negative correlation with the gas production of coalbed methane wells. The correlation between gas production and the mean three-dimensional stress is weak. As the fractal dimension D value of fractures increases, gas production decreases. A smaller difference in horizontal principal stress is more favorable for the formation of network fractures, facilitating reservoir fracturing and resulting in better reconstructive properties. Moreover, an increase in the sand–mud ratio leads to a decrease in average gas production. The correlation between fault fractal dimension and average gas production is weak. The grey correlation method was employed to determine the controlling factors of coalbed methane production in the study area, ranked from strong to weak, as follows: coal thickness > fracture fractal dimension D value > gas saturation > coal seam gas content > horizontal stress difference coefficient > permeability > critical desorption pressure > mean value of three-dimensional principal stress > coal seam burial depth > sand–mud ratio > fault fractal dimension.

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“…Currently, fossil fuels supply over 80% of the world's commercial energy 3,4 . A potent approach to combat climate change and global warming is to utilize coal bed methane (CBM) 5,6 . Coal bed methane (CBM), a significant source of unconventional natural gas worldwide, mainly consists of substantial amounts of CH 4 , minimal quantities of CO 2 and N 2 , and trace amounts of other gases 7,8 .…”

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confidence: 99%

Competitive adsorption of CO2, N2, and CH4 in coal-derived asphaltenes, a computational study

Valadi,

Pasandideh-Nadamani,

Rezaee

et al. 2024

Sci Rep

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Greenhouse gases are major contributors to global warming, and their concentration is increasing due to the widespread use of fossil fuels. Coal bed methane (CBM) offers a potential solution to this issue. However, the gas adsorption mechanisms of CBM, particularly in the context of coal-derived asphaltenes, are not fully understood. This study provides a comprehensive theoretical investigation of the competitive adsorption of carbon dioxide (CO$$_2$$ 2 ), methane (CH$$_4$$ 4 ), and nitrogen (N$$_2$$ 2 ) in the processes of CO$$_2$$ 2 - and N$$_2$$ 2 -enhanced coalbed methane recovery, with a focus on coal-derived asphaltenes functionalized with CH$$_4$$ 4 , NH, O, and S groups. Using the Grand Canonical Monte Carlo (GCMC) simulation method and performing Molecular Dynamics (MD) simulations, we studied the adsorption process. To investigate the electronic effects and nature of the interactions, we performed density functional theory (DFT) calculations. The adsorption energy values and non-covalent interactions (NCI) for the adsorption of gases signify the physical adsorption (van der Waals interaction), with CO$$_2$$ 2 exhibiting the highest (absolute) adsorption energy. The Monte Carlo results indicated that elevated temperatures led to a reduction in adsorption capacity. Coal-derived asphaltenes demonstrated greater selectivity for CO$$_2$$ 2 compared to CH$$_4$$ 4 and N$$_2$$ 2 in competitive adsorption, especially at elevated temperatures. Our findings highlight the significant potential of our asphaltene model, not only in mitigating CO$$_2$$ 2 greenhouse gas emissions but also in recovering CH$$_4$$ 4 , which is a valuable resource.

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Prediction of Critical Desorption Pressure of Coalbed Methane in Multi-coal Seams Reservoir of Medium and High Coal Rank: A Case Study of Eastern Yunnan and Western Guizhou, China

Cited by 9 publications

References 35 publications

Pore Fractal Characteristics of Different Macro-Coal Components and Influence on Adsorption/Desorption: A Case Study in the Huanglong Jurassic Coalfield

Pore Fractal Characteristics of Different Macro-Coal Components and Influence on Adsorption/Desorption: A Case Study in the Huanglong Jurassic Coalfield

Analysis of Coalbed Methane Production Characteristics and Influencing Factors of No. 15 Coal Seam in the Shouyang Block

Competitive adsorption of CO2, N2, and CH4 in coal-derived asphaltenes, a computational study

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