Formation and development of pore structure in marine-continental transitional shale from northern China across a maturation gradient: insights from gas adsorption and mercury intrusion

2018 ◽  
Vol 200 ◽  
pp. 87-102 ◽  
Author(s):  
Zhaodong Xi ◽  
Shuheng Tang ◽  
Jing Wang ◽  
Guoqiao Yang ◽  
Lei Li
2019 ◽  
Vol 7 (2) ◽  
pp. T547-T563 ◽  
Author(s):  
Jiyuan Wang ◽  
Shaobin Guo

To systematically study the whole-aperture pore-structure characteristics of the marine-continental transitional shale facies in the Upper Palaeozoic Taiyuan and Shanxi Formations of the Qinshui Basin, we have collected a total of 11 samples for high-pressure mercury intrusion, low-pressure gas adsorption ([Formula: see text] and [Formula: see text]), nuclear magnetic resonance (NMR), and field-emission scanning electron microscopy with argon-ion polishing experiments to determine the pore morphology and distribution characteristics of shale samples in detail and to perform quantitative analyses. Then compared the pore-development characteristics of the Taiyuan Formation samples with those of the Shanxi Formation to determine which is preferable. The experimental results indicate that the shale samples of the Qinshui Basin mainly develop three types of pores: organic pores, intergranular pores, and microfractures. High-pressure mercury intrusion and gas-adsorption experiments indicate that the pore-size distributions exhibit multiple peaks. The samples contained varying proportions of macropores, mesopores, and micropores, among which the former two are dominant, accounting for approximately 85% of the total pore volume, whereas micropores account for only 15%. However, mesopores and micropores dominate the specific surface area; between them, the micropores are much more prevalent, accounting for more than 99% of the total specific surface area. Macropores contribute less than 1% of the specific surface area and therefore can be neglected. The pore morphology resembles the slit type parallel platy pores with a ballpoint pen structure. The NMR [Formula: see text] spectra have multiple-peak values. In addition, the large difference between the curved areas before and after centrifugation indicates that the samples contain a large proportion of mesopores and macropores, which is consistent with the results presented above. The results demonstrate that the development of pores in the Taiyuan Formation is better than that in the Shanxi Formation.


Fuel ◽  
2013 ◽  
Vol 103 ◽  
pp. 606-616 ◽  
Author(s):  
C.R. Clarkson ◽  
N. Solano ◽  
R.M. Bustin ◽  
A.M.M. Bustin ◽  
G.R.L. Chalmers ◽  
...  

2010 ◽  
Vol 150-151 ◽  
pp. 825-828
Author(s):  
Yan Wang ◽  
Di Tao Niu ◽  
Yuan Yao Miao ◽  
Nai Qi Jiao

The concrete microstructure can affect its macroscopic properties, such as the strength and durability, etc. Based on the experimental study of cube compressive strength of steel fibre reinforced concrete, splitting tensile strength, flexural strength, and using by mercury intrusion method to test the pore structure of steel fibrous, this paper analyzes the influence of fibre on concrete pore structure. And then on mechanical properties of concrete from microcosmic perspective.


Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Run Chen ◽  
Yong Qin ◽  
Pengfei Zhang ◽  
Youyang Wang

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%.


2021 ◽  
Author(s):  
Barkat Ullah ◽  
Yuanping Cheng ◽  
Liang Wang ◽  
Weihua Yang ◽  
Izhar Mithal Jiskani ◽  
...  

Abstract Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical significance for coal bed methane and the prevention of dynamic disasters such as coal and gas outbursts. This study investigates the pore structure and fractural characteristics of soft and hard coals using nitrogen and carbon dioxide (N2/CO2) adsorption. Coal samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size (0.2-0.25mm). N2/CO2 adsorption tests were performed to evaluate the pore size distribution (PSD), specific surface area (SSA), and pore volume (PV). The pore structure was characterized based on fractural theory. The results unveiled that the strength of coal has a significant influence on pore structure and fracture dimensions. The obvious N2-adsorption isotherms of the coals were verified as Type IV (A) and Type II. The shape of the hysteresis loops indicates the presence of slit-shaped pores. There are significant differences in SSA and PV between both coals. The soft coal showed larger SSA and PV than hard coal that shows consistency with adsorption capacity. The fractal dimensions of soft coal are respectively larger than that of hard coal. The greater the value of D1 (complexity of pore surface) of soft coal is, the larger the pore surface roughness and gas adsorption capacity is. The results enable us to conclude that the characterization of pores and fractures of soft and hard coals is different, tending to different adsorption/desorption characteristics and outburst sensitivity. In this regard, results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.


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