scholarly journals Quantitative characterization method for microscopic heterogeneity in tight sandstone

2021 ◽  
pp. 014459872199393
Author(s):  
Tianxue Lv ◽  
Zhiping Li
Keyword(s):  
Fractal Dimension ◽  
Total Pore Volume ◽  
Physical Parameters ◽  
Surface Porosity ◽  
Tight Sandstone ◽  
Quantitative Characterization ◽  
Average Pore ◽  
Reservoir Evaluation ◽  
Discrete Values

Understanding the microheterogeneity of tight sandstone is the basis of reservoir science, and quantitative characterization of the reservoir’s microheterogeneity is key to reservoir evaluation. In this study, an image-processing analysis method to study the heterogeneity of tight reservoirs is established. A modified Image J plugin is used to accurately identify the surface porosity of a thin casting sheet; the heterogeneity of the microscopic pores in a reservoir is then abstracted into discrete values of the surface porosity. A new parameter for quantitative characterization of the microscopic heterogeneity of tight sandstone, that is, the heterogeneity index Q, is proposed. The fractal dimension calculated via a liquid nitrogen adsorption experiment is used to test the new parameter, and the geological significance of Q is discussed. The results show that Q has a good positive correlation with the fractal dimension, which is beneficial in determining the heterogeneity of the reservoir, pore throat distribution, and roughness of the pore surface. Q has a good correlation with physical parameters such as the specific surface area, average pore diameter, and total pore volume of the sample, indicating that this index can effectively characterize and quantitatively evaluate the reservoir. Therefore, this parameter provides a new basis for reservoir evaluation and classification and provides a new direction for delineating advantageous horizons as well as guiding development and mining.

scholarly journals The Production and Characterization of Activated Carbon Electrodes from Pineapple Leaf Fibers for Supercapacitor Application

2020 ◽  
Vol 9 (1) ◽  
pp. 1-8
Author(s):  
Agustino Agustino ◽  
Rakhmawati Farma ◽  
Erman Taer
Keyword(s):  
Activated Carbon ◽  
Chemical Activation ◽  
Total Pore Volume ◽  
Amorphous Structure ◽  
Physical Activation ◽  
Carbon Electrode ◽  
Average Pore ◽  
Average Pore Radius ◽  
Supercapacitor Application

Elektroda karbon aktif berbasis serat daun nanas (SDN) telah berhasil diproduksi dengan proses tiga langkah berikut ini, yaitu: (i) aktivasi kimia, (ii) karbonisasi, dan (iii) aktivasi fisika. Aktivasi kimia dilakukan dengan menggunakan agen pengaktif KOH dengan konsetrasi 0,3 M. Karbonisasi dilakukan dalam lingkungan gas N2 pada temperatur 600oC dan diikuti oleh aktivasi fisika pada temperatur 850oC menggunakan gas CO2 selama 2,5 jam. Luas permukaan spesifik elektroda 512,211 m2×g-1 dengan volume total pori sebesar 0,093 cm3×g–1, dan jari-jari pori rata-rata 1,199 nm. Morfologi permukaan elektroda karbon aktif menunjukkan adanya serat karbon dengan diameter serat dalam kisaran 101 - 185 nm dan memliki kandungan karbon dengan massa atomik sebesar 84,33%. Elektroda karbon aktif memiliki struktur amorf, yang ditunjukkan oleh dua puncak difraksi yang lebar pada sudut hamburan 24,64 dan 43,77o yang bersesuaian dengan bidang (002) dan (100). Kapasitansi spesifik, energi spesifik dan daya spesifik sel superkapasitor yang dihasilkan masing-masing sebesar 110 F×g-1, 15,28 Wh×kg-1 dan 36,69 W×kg-1. Pineapple leaf fiber (PALF) based activated carbon electrode has been successfully produced using three-step process, i.e. (i) chemical activation, (ii) carbonization, and (iii) physical activation. The chemical activation was carried out using KOH activating agent with a concentration of 0.3 M. The carbonization process is conducted out in N2 gas environment at 600oC and followed by physical activation at a temperature of 850oC by using CO2 gas for 2.5 h. The specific surface area of the electrode is 512.211 m2×g-1 with a total pore volume of 0.093 cm3×g-1, and average pore radius of 1.199 nm. The surface morphology of the electrode shown the carbon fibers with diameter in the range of 101 - 185 nm and carbon content with 84.33% of atomic mass. The activated carbon electrode has an amorphous structure, which is shown by two wide diffraction peaks at scattering angles of 24.64 and 43.77o which correspond to the plane (002) and (100), respectively. The specific capacitance, energy and power of the electrode are 110 F×g-1, 15.28 Wh×kg-1 and 36.69 W×kg-1, respectively.Keywords: Serat daun nanas, Kalium hidroksida, Elektroda karbon aktif, Kapasitansi spesifik, Superkapasitor 

scholarly journals Quantitative Characterization of Heterogeneity in Different Reservoir Spaces of Low-Permeability Sandstone Reservoirs and Its Influence on Physical Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Fengjuan Dong ◽  
Na Liu ◽  
Zhen Sun ◽  
Xiaolong Wei ◽  
Haonan Wang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
Low Permeability ◽  
Quantitative Characterization ◽  
Average Value ◽  
Porosity And Permeability ◽  
Sandstone Reservoirs

The complex pore structure of low-permeability sandstone reservoir makes it difficult to characterize the heterogeneity of pore throat. Taking the reservoir of Sanjianfang formation in QL oilfield as an example, the fractal dimension of different storage spaces is calculated by using fractal theory based on casting thin section, scanning electron microscope, and high-pressure mercury injection, and the correlation between porosity, permeability, and contribution of different storage space permeabilities is analyzed. The results show that the reservoir of Sanjianfang formation in QL oilfield mainly develops small pores, fine pores, and micropores, and the fractal dimension of micropore structure is between 2.6044 and 2.9982, with an average value of 2.8316. The more complex the pore structure is, the stronger the microheterogeneity is. The higher the fractal dimension, the more complex the pore structure and the smaller the porosity and permeability. The fractal dimensions of small pores, fine pores, and micropores increase successively with the decrease in pore radius, and the microstructure heterogeneity of large pores is weaker than that of small pores. It provides a theoretical basis for the exploration and development of low-permeability sandstone reservoirs.

Preparation and Characterization of Porous Silica Obtained by Hydrochloric Acid Selective Leaching Metakaolinite

2008 ◽  
Vol 368-372 ◽  
pp. 342-344
Author(s):  
Lin Jiang Wang ◽  
Xiang Li Xie
Keyword(s):  
Hydrochloric Acid ◽  
Layered Structure ◽  
Layer Structure ◽  
Average Pore Size ◽  
Porous Silica ◽  
Total Pore Volume ◽  
Selective Leaching ◽  
Average Pore ◽  
Hcl Solution

Porous silica was prepared by selective leaching of metakaolinite with 20 mass% HCl solution. The metakaolinite was derived from the 1:1 layered structure clay mineral kaolinite by firing at 600°C for 24 h. The characteristics of porous silica were studied. The content of Al2O3 in metakaolinite was sharply changed from 45% to less than 2% after 2 h leaching. The maximum specific surface area of the leached sample was about 350 m2/g. The average pore size is about 2 nm. The total pore volume is 0.3 ml/g. The layer structure of kaolinite and metakaolinite is responsible for forming micropores.

The quantitative characterization of the ignition process for a lean staged injector: Influence of the air split between pilot swirlers

2019 ◽  
Vol 234 (5) ◽  
pp. 1132-1145
Author(s):  
Jinhu Yang ◽  
Cunxi Liu ◽  
Fuqiang Liu ◽  
Yong Mu ◽  
Gang Xu
Keyword(s):  
Physical Parameters ◽  
Ignition Process ◽  
Quantitative Characterization ◽  
Partially Premixed Combustion ◽  
Discrete Phase ◽  
Quantitative Analyses ◽  
Partially Premixed ◽  
Ignition Kernel ◽  
Radial Propagation

The ignition of a lean staged injector aimed at aeronautical application is a transient and complex phenomenon, which involves fluid dynamics, turbulent mixing, chemical kinetics, as well as their mutual interactions. In the present research, a staged injector, designed based on stratified partially premixed combustion concept, is introduced. The ignition performance of stratified partially premixed injectors with different air split ratios between pilot swirlers are experimentally acquired, which exhibits apparent distinctions. In order to make quantitative analyses, the classical physical ignition model is improved, in which the flame propagation process is further divided into the axial and radial propagation sub-processes. Nonreacting flow field and discrete phase simulations, validated by experiment results, are utilized to obtain the velocity and spray distributions. Physical parameters characterizing the ignition sub-processes are defined and calculated based on the numerical simulation results. Conclusions are made by comparing the physical parameters of the ignition sub-processes. The radial propagation of the ignition kernel is responsible for the ignition performance difference between the two injectors with different pilot air split ratios (PASR) in that the average equivalence ratio along the radial propagation route of PASR = 7:3 is one order richer than that of PASR = 2:8. The present ignition analysis and model can be further extended and developed for the optimization of ignition performance of lean staged injector.

Characterization of TiO2 Film Prepared by Sol-Gel Method Using Ti(OC4H9)4

2011 ◽  
Vol 298 ◽  
pp. 249-252 ◽  
Author(s):  
Li Li Yang ◽  
Jia Wei Bai ◽  
Wen Jie Zhang
Keyword(s):  
Pore Size ◽  
Tio2 Film ◽  
Average Pore Size ◽  
Sol Gel ◽  
Total Pore Volume ◽  
Source Surface ◽  
Average Pore ◽  
Tio2 Particles ◽  
Sol Gel Process

TiO2 film was dip-coated on glass substrate by a sol-gel process. Ti(OC4H9)4 was used as the titanium source. Surface morphology, crystallite phase, UV-Vis transmittance spectrum and pore size distribution of TiO2 powder prepared under the same conditions of the film were investigated. Surface of TiO2 film is fairly smooth with very slight roughness. No obvious hole or pore is found on the surface of the film. The strongest diffraction peak situated at 2θ=25.3o is the characteristic of anatase TiO2. The absorption edge of the TiO2 film is around 350 nm, while the transmittance fluctuates between 50% and 90%. The average pore size of the TiO2 particles calculated by BJH method is 23 nm. The total pore volume and specific surface area are 0.16 ml/g and 27 m2/g, respectively.

scholarly journals Fractal Dimension for the Characterization of the Porosity of Asphalt Concretes

2010 ◽  
Vol 56 (4) ◽  
pp. 321-333 ◽  
Author(s):  
G. Leonardi
Keyword(s):  
Fractal Dimension ◽  
Asphalt Concrete ◽  
Experimental Approach ◽  
Asphalt Mixtures ◽  
Physical Parameters ◽  
Aggregate Gradation ◽  
Fractal Approach ◽  
Fractal Characteristics ◽  
Concrete Materials

Abstract In the design of asphalt mixtures for paving, the choice of components has a remarkable importance, as requirements of quality and durability must be assured in use, guaranteeing adequate standards of safety and comfort. In this paper, an approach of analysis on the aggregate materials using fractal geometry is proposed. Following an analytical and an experimental approach, it was possible to find a correlation between characteristics of the asphalt concrete (specific gravity and porosity) and the fractal dimension of the aggregate mixtures. The studies revealed that this approach allows to draw the optimal fractal dimension and, consequently, it can be used to choose an appropriate aggregate gradation for the specific application; once the appropriate initial physical parameters are finalized. This fractal approach could be employed for predicting the porosity of mixed asphalt concretes, given as input the fractal characteristics of the aggregate mixtures of the concrete materials

Preparation and Characterization of Sewage Sludge-Based Activated Carbon

2012 ◽  
Vol 599 ◽  
pp. 614-617 ◽  
Author(s):  
Zi Jun Tang ◽  
Chao Ping Cen ◽  
Ping Fang ◽  
Yang Ming Liang
Keyword(s):  
Activated Carbon ◽  
Sewage Sludge ◽  
Zinc Chloride ◽  
Removal Rate ◽  
Chemical Activation ◽  
Total Pore Volume ◽  
Bet Surface Area ◽  
Average Pore ◽  
Preparation Conditions

In this study, a sewage sludge-base activated carbon (SSAC) was prepared by means of ZnCl2 chemical activation-pyrolysis-carbonization. Different factors such as activated temperature, activators, additives, sludge/activation solution ratio, activated time and other factors which affecting SSAC characteristics were studied to obtain the optimal preparation conditions. The result shows that when using 3mol/L zinc chloride with the ratio of zinc chloride to sulfuric acid as 10:1(v/v), activated at 550°C with the ratio of sludge to activation solution as 1:4(w/v) for 1 hour of pyrolysis and the rate of N2 was set at 0.5L/min, the BET surface area, total pore volume and average pore diameter of the SSAC was 469.80m2/g, 0.16cm3/g and 2.60nm respectively. Using SSAC to treat simulating wastewater containing 100mg(Ni2+)/L, the removal rate of Ni2+ was 20.59% with the adsorption capacity of 10.57mg/g. When the pH>10.5 the removal efficiency approached 100%.

Characterization of Porous TiO2 Films Prepared Using PEG of Different Molecular Weight

2011 ◽  
Vol 298 ◽  
pp. 253-256
Author(s):  
Li Li Yang ◽  
Jia Wei Bai ◽  
Wen Jie Zhang
Keyword(s):  
Molecular Weight ◽  
Surface Roughness ◽  
Wavelength Region ◽  
Total Pore Volume ◽  
Dip Coating ◽  
Tio2 Films ◽  
Average Pore ◽  
Glass Substrates ◽  
Different Molecular Weight

Porous TiO2 films were prepared through dip-coating on glass substrates using different molecular weight of PEG. Surface roughness increased with increasing PEG molecular weight. The film prepared with PEG400 was fairly smooth with slight roughness. The films prepared with high molecular PEG became rougher and there were some larger particles on the films. When the PEG molecular weight got higher, adsorption edge of the films tended to move toward shorter wavelength region. In the wavelength range between 350 and 450 nm, larger PEG molecules made higher film transmittance. The particles prepared using higher or lower molecular weight of PEG had less surface area than using PEG1000. The average pore sizes were 14 nm, 15 nm, 28 nm, and 52 nm, and the total pore volume were 0.12 ml/g, 0.13 ml/g, 0.08 ml/g, and 0.09 ml/g for the TiO2 powders prepared using PEG400 to PEG 6000.

scholarly journals FRACTAL NATURE OF POROSITY IN VOLCANIC TIGHT RESERVOIRS OF THE SANTANGHU BASIN AND ITS RELATIONSHIP TO PORE FORMATION PROCESSES

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840007 ◽  
Author(s):  
WEIMING WANG ◽  
ZHIXUAN WANG ◽  
XUAN CHEN ◽  
FEI LONG ◽  
SHUANGFANG LU ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Organic Acids ◽  
Source Rock ◽  
Volcanic Rocks ◽  
Morphological Characteristics ◽  
Total Pore Volume ◽  
Internal Surface ◽  
Source Rocks ◽  
Average Pore ◽  
Tight Reservoirs

In this paper, in a case study of Santanghu Basin in China, the morphological characteristics and size distribution of nanoscale pores in the volcanic rocks of the Haerjiawu Formation were investigated using the results of low temperature nitrogen adsorption experiments. This research showed that within the target layer, a large number of nanoscale, eroded pores showed an “ink bottle” morphology with narrow pore mouths and wide bodies. The fractal dimension of pores increases gradually with increasing depth. Moreover, as fractal dimension increases, BET-specific surface area gradually increases, average pore diameter decreases and total pore volume gradually increases. The deeper burial of the Haerjiawu volcanic rocks in the Santanghu Basin leads to more intense erosion by organic acids derived from the basin’s source rocks. Furthermore, the internal surface roughness of these corrosion pores results in poor connectivity. As stated above, the corrosion process is directly related to the organic acids generated by the source rock of the interbedded volcanic rocks. The deeper the reservoir, the more the organic acids being released from the source rock. However, due to the fact that the Haerjiawu volcanic rocks are tight reservoirs and have complicated pore-throat systems, while organic acids dissolve unstable minerals such as feldspars which improve the effective reservoir space; the dissolution of feldspars results in the formation of new minerals, which cannot be expelled from the tight reservoirs. They are instead precipitated in the fine pore throats, thereby reducing pore connectivity, while enhancing reservoir micro-preservation conditions.

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