nanoscale pore
Recently Published Documents


TOTAL DOCUMENTS

74
(FIVE YEARS 30)

H-INDEX

14
(FIVE YEARS 4)

2021 ◽  
Vol 12 ◽  
pp. 100076
Author(s):  
M. Kodama ◽  
A. Takeuchi ◽  
M. Uesugi ◽  
T. Miyuki ◽  
H. Yasuda ◽  
...  

Fuel ◽  
2021 ◽  
Vol 306 ◽  
pp. 121621
Author(s):  
Zhen Ni ◽  
Baiquan Lin ◽  
Xiangliang Zhang ◽  
Xuan Cao ◽  
Lubin Zhong ◽  
...  

2021 ◽  
Vol 14 (22) ◽  
Author(s):  
Yang Zhifeng ◽  
Tang Yong ◽  
Guo Xuguang ◽  
Huang Liliang ◽  
Chang Qiusheng

AbstractUsing observations and descriptions of drilling cores, image logging, microscopic section, argon ion polishing field emission scanning electron microscopy, X-ray diffraction, and whole-rock trace element analysis, the study of shale reservoir diagenesis and space types in the Fengcheng Formation of the Mahu Sag was conducted. Considering the trace element contents and their ratios (Sr/Ba, V/Ni, Th/U, V/(V + Ni), U/Mo, and Sr/Cu), the Fengcheng Formation is formed in a dry and hot continental lacustrine basin with a paleoenvironment of saltwater and anoxic/lean oxygen conditions. The shale reservoirs of the Fengcheng Formation with the characteristic of multisource mixed sedimentation include terrigenous clastic, volcaniclastics, and carbonate rocks. Currently, the Fengcheng reservoir of the Mahu Sag is in the middle of diagenetic-stage B. The principal factors for reservoir densification are compaction, dissolution, carbonate mineral cementation, and clay mineral cementation. The Fengcheng Formation develops multiple reservoir storage space types, such as rock fractures, stylolites, and micro–nanoscale pore-throat systems. The macroreservoir space types include tectonic, induced, bedding, and dissolution–expansion fracture types. The microreservoir space types include microfractures, stylolites, and micro–nanoscale pore throats. The research showed that the Fengcheng Formation has tectonic fracture-pore systems (tectonic fracture-type reservoirs) and stylolite-matrix pore-tectonic microfracture systems (shale oil reservoirs), forming the shale oil preponderant charging channel network. Reservoir space type and its spatial distribution are the principal factors for shale oil accumulation of the Fengcheng Formation in the Mahu Sag.


Author(s):  
Mohamed Garum ◽  
Paul W. J. Glover ◽  
Piroska Lorinczi ◽  
Stuart Micklethwaite ◽  
Ali Hassanpour

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Jingyi Wang ◽  
Qinhong Hu ◽  
Mengdi Sun ◽  
Zhongxian Cai ◽  
Cong Zhang ◽  
...  

The evaluation of pore structure is an essential part in the assessment of carbonate reservoirs. The structures (geometry and connectivity) of nm to μm-scale pore networks in outcrop samples of carbonates from Xiaoerbulake Formation in Tarim Basin of China were studied by using optical microscopy, field emission-scanning electron microscopy (FE-SEM), as well as mercury intrusion porosimetry (MIP) with fractal analyses of the data, and spontaneous imbibition tests (distilled water). The results demonstrate that the lithologies are micritic dolomites, fine-to-medium-to-coarse crystalline dolomites, microbial dolomites, and dolarenite. At micro- to nanoscales in size, pore types are dominated by intergranular, intercrystalline, and intragranular (e.g., dissolution) pores. These pore networks have pore-throat diameters from 0.01 to >10 μm. Compared with a nanoscale pore network, the μm-scale pore networks are relatively well connected and serve as the most important permeability pathways. Although the pore volume accounts for most of the total porosity, the permeability of nanoscale pore networks is low. The existence of micro-nano-fractures could improve connectivity, especially for the nanoscale pore networks, by linking the intragranular (dissolution) pores which are mostly in the range of nm-scale.


2021 ◽  
Vol 21 (1) ◽  
pp. 567-577
Author(s):  
Jun He ◽  
Mingke Wang ◽  
Jienan Pan ◽  
Xianglong Wang ◽  
Yiju Tang

To understand the nanoscale pore development characteristics of closed coal under the combined influence of temperature and confined pressure, a series of experiments at different temperatures and pressures were carried out using a custom closed coal temperature and pressure experimental system. The lean coal samples were taken from a mining area in Qinshui Basin, North China. In these experiments, the temperature was 200 °C or 300 °C, the pressure was 14 MPa or 23 MPa, respectively, and the experiment duration was 12 h. The CH4/N2/CO2 isothermal adsorption tests were carried out on all samples. The results show that the custom experimental system can be used to effectively study the effect of mechanical-thermal interaction on the nanoscale pores in closed coal. Before and after the experiment, the Langmuir volume increases, and the methane adsorption capacity increases. The specific surface area and pore volume of the micropores (<1 nm) decrease, but the specific surface area and pore volume of the pores (6–100 nm) increase. The specific surface area and pore volume of the micropores (<1 nm) are negatively correlated with the temperature and decrease with increasing temperature. Fractal analysis results show that under the influence of temperature and pressure, the heterogeneity of the nanoscale pore structure and the roughness of the pore surface increase. This research is of important theoretical significance for the safe mining of deep coal seams and for the development of coalbed methane resources.


2021 ◽  
Vol 21 (1) ◽  
pp. 156-167
Author(s):  
Yang Wang ◽  
Caifang Wu ◽  
Yong Qin ◽  
Shimin Liu ◽  
Rui Zhang

Shale gas has received widespread interest due to its successful commercial development in China. Pore structures in shale can directly control its gas storage and migration properties. In this study, field emission scanning electron microscopy (FE-SEM), low-pressure N2/CO2 adsorption and highpressure methane adsorption were used to investigate the nanoscale pore structures of the Lower Cambrian Niutitang Formation in the southeastern Upper Yangtze platform. The fractal parameters of the pore structures were also calculated using the Frenkel–Halsey–Hill (FHH) model. The relationships between the fractal dimensions and TOC content, mineral composition and pore structure parameters were also discussed. The results show that organic matter and clay minerals are primary factors affecting the nanoscale pore development. Slit-shaped pores and ink-bottle-shaped pores are the predominant pore types in the Niutitang shale. The Brunauer-Emmett-Teller (BET) surface areas vary from 4.91 m2/g to 34.33 m2/g, and the pore volumes range from 0.689 m3/100 g to 2.964 m3/100 g. Two fractal dimensions (D1 and D2) of the Niutitang shale were obtained using the FHH model, with D1 ranging from 2.605 to 2.684, and D2 ranging from 2.681 to 2.865. D1 adequately characterizes the surface roughness of the pore structures, while D2 represents the complexity of the pore types. Inter-particle (InterP) pores commonly have greater shape complexities than OM pores and intra-particle (IntraP) pores, based on analyses using Image-Pro Plus software. In addition, the TOC content and clay minerals have great effects on the fractal dimension D1. Meanwhile, the fractal dimension D1 increases with increasing BET surface area, but there is no definite relationship between the fractal dimensions and pore volumes. Both the fractal dimensions D1 and D2 are negatively correlated with pore sizes. Further investigation indicates that the fractal dimension D1 exhibits a strong positive relationship with the methane adsorption capacity indicating that Niutitang shales with greater values of the fractal dimension D1 have higher methane adsorption capacities.


2021 ◽  
Vol 21 (1) ◽  
pp. 139-155
Author(s):  
Xiaoliang Wei ◽  
Qian Chen ◽  
Jinchuan Zhang ◽  
Haikuan Nie ◽  
Wei Dang ◽  
...  

Fractal dimension is closely related to the nanoscale pore structure of shale, and it also has an important influence on the gas content of shale. To investigate the correlation between the fractal dimension and the methane (CH4) bearing features of shale, seven Permian shale samples were analyzed with field emission scanning electron microscopy (FE-SEM), low temperature nitrogen (N2), carbon dioxide (CO2) and CH4 adsorption and on-site gas desorption experiments. Based on the N2 adsorption and desorption data, we proposed a new method to better determine the gas adsorption stage at different relative pressure (P/P0) points in the multilayer adsorption or capillary condensation stage. On this basis, two fractal dimensions, D1 (representing the surface roughness) and D2 (representing pore irregularity), were obtained. By correlating the fractal dimensions and nanoscale pore structure parameters, we found that D1 does not correlate with the pore structure parameters except for the micropore volume. Influenced by the aggregation of porous and nonporous materials, D2 has a positive linear relationship with the specific surface area (SSA) and micropore volume but has a negative linear correlation with the average diameter of pores. D1 is negatively correlated with water saturation and positively correlated with free CH4 content. The CH4 adsorption content is positively correlated with D2. By fitting the on-site desorption data, the positive correlation between the total desorbed CH4 content and the desorbed CH4 content in stage 2 and D2 was also confirmed. D2 better reflects the CH4 adsorption capacity of organic-rich shale than D1. However, D1 can be used to reflect the influence of shale surface properties on water saturation and to indirectly reflect the free CH4 content in shale. The fractal dimension (D1 and D2) is a clear indicator of the total free and adsorbed CH4 content, but cannot indicate the desorbed CH4 content at different stages.


Sign in / Sign up

Export Citation Format

Share Document