Fractal Dimension Determination of Rock Pores by Multi-Scale Analysis of Images Obtained Using Om, Sem and XCT

Alfonso, I.; Beltrán, Alberto; Abatal, Mohamed; Castro, Iván; Fuentes, Alejandra; Vázquez, Leonor; Garcia, Armando R.

doi:10.1142/s0218348x18500676

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…Subsequently, the images are covered with boxes of the length δ. The fracture ratio η and fracture fractal dimension are calculated by eqs and , − respectively where η is the percentage of area occupied by microfracture in the SEM image and N (δ) and N 1 (δ) are the number of boxes required to cover the binary image and to cover the fracture, respectively. From eq , can be derived that is expressed in the linear equation , Therefore, based on the box-counting method, the fracture fractal dimension D 1 of coal can be acquired from the regression linear slope of the plot of ln ( N (δ)) vs ln (δ).…”

Section: Methodsmentioning

confidence: 99%

Coupling Effect of Temperature, Gas, and Viscoelastic Surfactant Fracturing Fluid on the Microstructure and its Fractal Characteristics of Deep Coal

Wang

et al. 2021

Energy Fuels

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The study of the microstructure evolution law of coal in a natural reservoir environment for the extraction of coalbed methane mining (ECBM), especially deep ECBM, is of major significance. We treated coal samples from Qinshui Basin under combined temperature–gas–fracturing fluid conditions and analyzed the evolution of the microstructure and its fractal characteristics to study the microstructural evolution of coal under natural hydraulic fracturing conditions. In the temperature range of 303.15 to 343.15 K and the gas-pressure range of 0.5–4.5 MPa, our data demonstrate that the pore structure is more susceptible to the temperature influence, compared with microfracture. The treatment of viscoelastic surfactant fracturing fluid (VES-FF) can effectively increase the permeation pore and fracture ratio by more than 300% and reduce the adsorption pore by more than 200% through dissolution, gas wedge, and other effects, which is favorable to ECBM. At the same temperature, as the gas pressure increases, the pore decreases, whereas the fracture ratio increases. The pore fractal dimension ranges from 2.90 to 2.99, which is significantly higher than that of microfractures. The temperature has a minor effect on the fracture fractal dimension, but it causes a decrease in the pore fractal dimension. The treatment of VES-FF induces an increase in the fracture fractal dimension, implying an increase in the fractal complexity. In contrast, the pore fractal characteristics show a contrary trend. At a gas pressure of 4.5 MPa, the negative effect of VES-FF on the pore structure reaches its maximum, whereas the effect on the fracture drops to its minimum. The results document that high temperature and high gas pressure can severely limit the penetration enhancement effect of VES-FF.

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Section: Methodsmentioning

confidence: 99%

Coupling Effect of Temperature, Gas, and Viscoelastic Surfactant Fracturing Fluid on the Microstructure and its Fractal Characteristics of Deep Coal

Wang

et al. 2021

Energy Fuels

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“…e box-counting dimension method [37,38] is one of the classic methods for calculating the fractal dimension of images. First, the image is binarized and the binarized image is placed on the flat.…”

Section: Fractal Model Based On the Box Dimension Methodmentioning

confidence: 99%

Experimental Study on Pore Characteristics and Fractal Dimension Calculation of Pore Structure of Aerated Concrete Block

Jun

2019

Advances in Civil Engineering

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It is important to control and predict the macroscopic properties through pore structure parameters of cement-based materials. Microscopic pore structure of concrete has many characteristics, such as sizes and disordered distribution. It is necessary to use fractal theory to describe the pore structure of concrete. In order to establish the relationship between the pore structure characteristics of aerated concrete and porosity, shape factor, pore superficial area, average pore diameter, and average diameter, the fractal dimension of the pore structure was used to evaluate the pore structure characteristics of aerated concrete. The X-ray computed tomography (CT) images of the aerated concrete block pore structure were obtained by using the XTH320 series X-ray three-dimensional microscope. The pore characteristics of aerated concrete block were studied according to Image-Pro Plus (IPP). Based on the research of the fractal dimension measurement methods, the proposed MATLAB program automatically determined the fractal dimension of the aerated concrete block pore structure images. The research results indicated that the small pores (20 μm∼60 μm) of aerated concrete block account for a large percentage compared with the large pores (60 μm∼400 μm or more) from pore diameter distribution and the pore structure of aerated concrete block has obvious fractal features and the fractal dimension of aerated concrete block pore structure images were calculated to be in the range of 1.775–1.805. The pore fractal dimension has a strong correlation with the pore fractal characteristics of aerated concrete blocks. The fractal dimension of the pore structure linearly increases with porosity, shape factor, and pore surface area. The fractal dimension of the pore structure decreases with the average pore size and average diameter. Thus, the fractal dimension of the pore structure that is calculated by the MATLAB program based on fractal theory can be assumed as the integrative evaluation index for evaluating the pore structure characteristic of aerated concrete block.

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“…The OM, SEM and XCT two-dimensional images of rocks were analyzed by Alfonso et al [13] based on the box counting method. The fractal dimension was obtained using the power-law distribution of the three types of images.…”

Section: Introductionmentioning

confidence: 99%

Application of Fractals to Evaluate Fractures of Rock Due to Mining

Yang

Liu

2022

Fractal Fract

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Fractures caused by mining are the main form of water inrush disaster. However, the temporal and spatial development characteristics of fractures of the rock mass due to mining are not clearly understood at present. In this paper, two geometric parameters, namely, fractal dimension and fracture entropy, are proposed to determine the spatial and temporal states of rock mass fractures caused by mining. The spatial and temporal structure characteristics of fractures in the rock mass due to mining are simulated with physical scale model testing based on digital image processing technology. A spatiotemporal model is created to examine the spatial and temporal patterns of hot and cold spots of the fractures based on a Geographic Information System (GIS). Results indicate that the fractal dimensions and entropy of the fractures network in the rock mass increase and decrease with the progression of mining, respectively, which can be examined in three stages. When the fractal dimension of the fractures in rock mass rapidly increases, the conductive fracture zone has a saddle shape. The fracture entropy of fracture has periodic characteristics in the advancing direction of the panel, which reflects the characteristics of periodic weighting. The fractal dimension and fracture entropy of fractures of the rock mass increase with time, and the rock mass system undergoes a process of increasing entropy. When the fractal dimension and fracture entropy of the fractures increase, the spatiotemporal state of fractures in rock mass caused by mining is initiated. When the fractal dimension and fracture entropy of the fractures decrease, the spatiotemporal state of fractures in rock mass is closed.

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Fractal Dimension Determination of Rock Pores by Multi-Scale Analysis of Images Obtained Using Om, Sem and XCT

Cited by 17 publications

References 16 publications

Coupling Effect of Temperature, Gas, and Viscoelastic Surfactant Fracturing Fluid on the Microstructure and its Fractal Characteristics of Deep Coal

Coupling Effect of Temperature, Gas, and Viscoelastic Surfactant Fracturing Fluid on the Microstructure and its Fractal Characteristics of Deep Coal

Experimental Study on Pore Characteristics and Fractal Dimension Calculation of Pore Structure of Aerated Concrete Block

Application of Fractals to Evaluate Fractures of Rock Due to Mining

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