Methane Adsorption Capacity of Deep-Buried Coals Based on Pore Structure in the Panji Deep Area of Huainan Coalfield, China

2021 ◽  
Vol 35 (6) ◽  
pp. 4775-4790
Author(s):  
Qiang Wei ◽  
Kaige Zheng ◽  
Baolin Hu ◽  
Xianqing Li ◽  
Songbao Feng ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Methane Adsorption ◽  
Huainan Coalfield ◽  
Deep Area

scholarly journals Changes in Pore Structure of Coal Caused by CS2 Treatment and Its Methane Adsorption Response

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Run Chen ◽  
Yong Qin ◽  
Pengfei Zhang ◽  
Youyang Wang
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Recovery Process ◽  
Micropore Volume ◽  
Methane Adsorption ◽  
Coal Bed ◽  
Methane Recovery ◽  
Before And After ◽  
Key Issues

The pore structure and gas adsorption are two key issues that affect the coal bed methane recovery process significantly. To change pore structure and gas adsorption, 5 coals with different ranks were treated by CS2 for 3 h using a Soxhlet extractor under ultrasonic oscillation conditions; the evolutions of pore structure and methane adsorption were examined using a high-pressure mercury intrusion porosimeter (MIP) with an AutoPore IV 9310 series mercury instrument. The results show that the cumulative pore volume and specific surface area (SSA) were increased after CS2 treatment, and the incremental micropore volume and SSA were increased and decreased before and after Ro,max=1.3%, respectively; the incremental big pore (greater than 10 nm in diameter) volumes were increased and SSA was decreased for all coals, and pore connectivity was improved. Methane adsorption capacity on coal before and after Ro,max=1.3% also was increased and decreased, respectively. There is a positive correlation between the changes in the micropore SSA and the Langmuir volume. It confirms that the changes in pore structure and methane adsorption capacity due to CS2 treatment are controlled by the rank, and the change in methane adsorption is impacted by the change of micropore SSA and suggests that the changes in pore structure are better for gas migration; the alteration in methane adsorption capacity is worse and better for methane recovery before and after Ro,max=1.3%. A conceptual mechanism of pore structure is proposed to explain methane adsorption capacity on CS2 treated coal around the Ro,max=1.3%.

Effect of nanometer pore structure on methane adsorption capacity in organic-rich shale

2019 ◽  
Vol 37 (11) ◽  
pp. 1243-1250 ◽  
Author(s):  
Cheng Zhong ◽  
Qirong Qin ◽  
Cunhui Fan ◽  
Dongfeng Hu
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Methane Adsorption

INVESTIGATION OF FRACTAL CHARACTERISTICS AND METHANE ADSORPTION CAPACITY OF THE UPPER TRIASSIC LACUSTRINE SHALE IN THE SICHUAN BASIN, SOUTHWEST CHINA

Fractals ◽  
2019 ◽  
Vol 27 (01) ◽  
pp. 1940011 ◽  
Author(s):  
LEI CHEN ◽  
ZHENXUE JIANG ◽  
KEYU LIU ◽  
WEI YANG ◽  
SHU JIANG ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Sichuan Basin ◽  
Southwest China ◽  
Upper Triassic ◽  
Methane Adsorption ◽  
Relative Pressure ◽  
Pore Surface ◽  
Fractal Characteristics ◽  
The Sichuan Basin

To better understand the nanopore characteristics and their effects on methane adsorption capacity of shales, we performed fractal analysis of nine shale samples collected from the fifth member of Upper Triassic Xujiahe Formation in the Sichuan Basin, southwest China. [Formula: see text] adsorption results show that shales have different adsorption characteristics at relative pressure of 0–0.5 and 0.5–1. Two fractal dimensions [Formula: see text] and [Formula: see text] were calculated using the Frenkel–Halsey–Hill (FHH) equation. Results show that the methane adsorption capacity increases with the increase of [Formula: see text] and [Formula: see text], of which [Formula: see text] has a more significant influence on adsorption capacity than [Formula: see text]. Further studies indicate that [Formula: see text] represents the pore surface fractal characteristics caused by the irregularity of shale surface, whereas [Formula: see text] represents the pore structure fractal characteristics, which is mainly affected by shale components (e.g. TOC, clay minerals) and pore parameters (e.g. average pore diameter, micropores content). A higher [Formula: see text] corresponds to a more irregular pore surface, which provides more space for methane adsorption. While a higher [Formula: see text] indicates a more complex pore structure and a stronger capillary condensation action on the pore surface, which in turn enhances the methane adsorption capacity.

Effects of pore structure and wettability on methane adsorption capacity of mud rock: Insights from mixture of organic matter and clay minerals

Fuel ◽  
2019 ◽  
Vol 251 ◽  
pp. 551-561 ◽  
Author(s):  
Peng Luo ◽  
Ningning Zhong ◽  
Imran Khan ◽  
Xiaomei Wang ◽  
Huajin Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Structure ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Methane Adsorption

Characterization of Pore Structure and Its Relationship with Methane Adsorption on Medium-High Volatile Bituminous Coal: An Experimental Study Using Nuclear Magnetic Resonance

2021 ◽  
Vol 21 (1) ◽  
pp. 515-528
Author(s):  
Baoxin Zhang ◽  
Xuehai Fu ◽  
Ze Deng ◽  
Ming Hao
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pore Structure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Adsorption Capacity ◽  
Size Distribution ◽  
Bituminous Coal ◽  
Methane Adsorption ◽  
Nuclear Magnetic

A number of studies have used the nuclear magnetic resonance (NMR) technique to analyse pore characteristics and to discuss the influencing mechanisms of pore structure on methane adsorption. However, there are few studies on the dynamic characteristics of methane adsorption over time under the same temperature and pressure conditions, especially by using the cylindrical coal samples. In this study, scanning electron microscopy (SEM), mercury injection porosimetry (MIP), isothermal adsorption and NMR techniques were carried out on the four medium-high volatile bituminous coal samples from Shanxi Province, China. The simulation of methane adsorption was carried out with the custom adsorption instruments. Based on the experimental results and the Hodot pore size classification standard, the pore size distribution of the samples was analysed. In addition, the influence of nanopore structure and water content on methane adsorption was discussed. The results show that the T2 relaxation diagram of the four coal samples has a bimodal-triple peak, which reflects the complexity of the pore structure. Due to the clay minerals filling microfractures in the sample HX, the connectivity of the nanopores is reduced, in addition there is an obvious gap between the peaks in the relaxation diagram. After calculation of the T2 relaxation diagrams of the coals, the results can be converted into the pore size distribution map. The pores in the four samples are mainly composed of the macropores, followed by the mesopores, and the ratio of micropores and transition pores is relatively small. At Sw (saturated in 5% brine for 24 h) and Sir (dried at 333 K for 3 h) conditions, the adsorption capacity of the four samples presented a positive correlation with the effective porosity and the ratio of micropores, and presented a negative correlation with the ratio of mesopores, while the macropores contribute less to the adsorption. Compared with samples at Sw conditions, the adsorption capacity of the samples at Sir conditions shows an overall increasing trend, which is approximately 1.6 times that of the samples at Sw conditions on average. When a large amount of liquid water invades the nanopores and fractures, the water occupies the adsorption space of the methane due to the wettability effects and capillary pressure, which reduces the adsorption capacity.

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