Effects of pore structure on methane adsorption behavior of ductile tectonically deformed coals: An inspiration to coalbed methane exploitation in structurally complex area

2020 ◽  
Vol 74 ◽  
pp. 103083 ◽  
Author(s):  
Guoxi Cheng ◽  
Bo Jiang ◽  
Ming Li ◽  
Jiegang Liu ◽  
Fengli Li
Keyword(s):  
Pore Structure ◽  
Coalbed Methane ◽  
Methane Adsorption ◽  
Adsorption Behavior ◽  
Tectonically Deformed Coals

scholarly journals Microscopic Pore Structure Characteristics and Methane Adsorption of Vitrain and Durain

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Fu Yang ◽  
Dongmin Ma ◽  
Zhonghui Duan ◽  
Dazhong Ren ◽  
Tao Tian ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Pore Structure ◽  
Coalbed Methane ◽  
Nitrogen Adsorption ◽  
Ash Content ◽  
Methane Adsorption ◽  
Low Rank ◽  
Reservoir Evaluation ◽  
Structure Characteristics ◽  
Carbon Dioxide Co2

During reservoir evaluation, the microscopic pore structure of low-rank coal is mainly characterized in order to study the coalbed methane diffuse and migration mechanisms and control. The low-rank coals are very different in pore type and size, so it is necessary to use various techniques to describe their pore structure. For vitrain and durain of the Coal Member of the Yan’an Formation from Huanglong Coalfield, their chemical composition and microscopic pore structure characteristics were studied, and the factors of influencing the pore size distribution (PSD) were explored. Obviously, vitrain and durain are different in chemical composition. Vitrain has higher moisture content, volatile yield, and vitrinite group content than durain. Vitrain and durain mainly contain vitrinite and inertinite, respectively. The pore structure characteristics (e.g., pore types and PSD) of vitrain and durain were systematically by mercury intrusion porosimetry (MIP), low-temperature nitrogen adsorption, and carbon dioxide (CO2) adsorption. The vitrain and durain samples with a micropore size of <2 nm were mainly tested on their specific surface area (SSA) and pore volume (PV). The results show that microporous vitrain has larger SSA and PV than microporous durain, while mesoporous and macroporous vitrain has smaller SSA and PV than mesoporous and macroporous durain. SSA is very positively correlated with PV. The ash content is negatively correlated with SSA and PV. The ash content influences microporous vitrain more greatly than microporous durain, but mesoporous and macroporous durain more greatly than mesoporous and macroporous vitrain. SSA is positively correlated with the vitrinite content of durain and negatively correlated with the inertinite and exinite contents of durain. However, SSA is negatively correlated with the vitrinite and exinite contents of vitrain and positively correlated with the inertinite content of vitrain. Vitrain has higher methane adsorption capacity, desorption rate, and recovery ratio than durain. There are parameters that are obviously affected by the micropore characteristics.

The impact of pore structure and adsorption behavior on kerogen tortuosity

Fuel ◽  
2021 ◽  
Vol 303 ◽  
pp. 121261
Author(s):  
Clement Afagwu ◽  
Saad Al-Afnan ◽  
Shirish Patil ◽  
Jaber Aljaberi ◽  
Mohamed A. Mahmoud ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorption Behavior ◽  
The Impact

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%.

Role of chemical structures in coalbed methane adsorption for anthracites and bituminous coals

Adsorption ◽  
2017 ◽  
Vol 23 (5) ◽  
pp. 711-721 ◽  
Author(s):  
Yongshuai Fu ◽  
Xianfeng Liu ◽  
Boqing Ge ◽  
Zhenghong Liu
Keyword(s):  
Coalbed Methane ◽  
Methane Adsorption ◽  
Chemical Structures ◽  
Bituminous Coals

The Role of Adsorbed Water on Pore Structure Characteristics and Methane Adsorption of Shale Clay

2018 ◽  
Author(s):  
Dong Feng ◽  
Xingfang Li ◽  
Chaojie Zhao ◽  
Jing Li ◽  
Qing Liu ◽  
...  
Keyword(s):  
Pore Structure ◽  
Adsorbed Water ◽  
Methane Adsorption ◽  
Structure Characteristics

Differences in petrophysical and mechanical properties between low- and middle-rank coal subjected to liquid nitrogen cooling in coalbed methane mining

2021 ◽  
pp. 1-10
Author(s):  
Menglin Du ◽  
Feng Gao ◽  
Chengzheng Cai ◽  
Shanjie Su ◽  
Zekai Wang
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Liquid Nitrogen ◽  
Coalbed Methane ◽  
Bituminous Coal ◽  
Thermal Damage ◽  
Physical And Mechanical Properties ◽  
Damage Degree ◽  
Lignite Coal ◽  
The Difference

Abstract Exploring the damage differences between different coal rank coal reservoirs subjected to liquid nitrogen (LN2) cooling is of great significance to the rational development and efficient utilization of coalbed methane. For this purpose, the mechanical properties, acoustic emission (AE) characteristics and energy evolution law of lignite and bituminous coal subjected to LN2 cooling were investigated based on the Brazilian splitting tests. Then, pore structure changes were analyzed to reveal the difference in the microscopic damage between lignite and bituminous coal after LN2 cooling. The results showed that compared with bituminous coal, the pore structure of lignite coal changed more obviously, which was manifested as follows: significant increases in porosity, pore diameters, and pore area; a larger transformation from micropores and transition pores to mesopores and macropores. After LN2 cooling, the thermal damage inside lignite and bituminous coal was 0.412 and 0.069, respectively. The thermal damage reduced the cohesive force between mineral particles, leading to the deterioration of the macroscopic physical and mechanical properties. Simultaneously, denser AE ringing counts and larger accumulated ringing counts were observed after LN2 cooling. Moreover, the random distribution of thermal damage enhanced the randomness of the macrocrack propagation direction, resulting in an increase in the crack path tortuosity. With more initial defects inside coal, a more obvious thermal damage degree and wider damage distribution will be induced by LN2 cooling, leading to more complicated crack formation paths and a higher fragmentation degree, such as that of lignite coal.

Sign in / Sign up

Export Citation Format

Share Document