Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Wu, Yuqi; Tahmasebi, Pejman; Lin, Chengyan; Munawar, Muhammad Jawad; Cnudde, Veerle

doi:10.1016/j.jhydrol.2019.05.014

Cited by 78 publications

(28 citation statements)

References 66 publications

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“…The “maximum ball” algorithm was used to extract regularized pore and throat models for 3D digital core images after binary segmentation to represent the pore space 51‐53 . The pore structure model simplifies the pore space of the 3D digital core but retains the pore space distribution characteristics of the original core image.…”

Section: Resultsmentioning

confidence: 99%

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

Zhao

Dong

Zhang

et al. 2020

Energy Science & Engineering

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Investigating the pore structure of shale rocks plays an important role in understanding the mechanism of shale oil accumulation and migration; thus, it has a notable influence on the exploration and development of shale oil resources. In the present study, the microstructure of oil shale samples extracted from the Shahejie Formation in the Dongying Depression was investigated through the joint usage of focused ion beam (FIB) and scanning electron microscopy (SEM). Herein, we selected four representative samples. The SEM images of the sample surfaces milled by FIB indicated that pores were found in both the organic and inorganic matter. Organic pores were less developed in the samples because of the low thermal maturity of the organic matter. Continuous 3D digital rock images of shale samples were generated by FIB grinding and SEM in situ imaging. Based on multithreshold segmentation, the shale rocks were separated into different parts including kerogen, inorganic matter, and pores. The pore connectivity and pore size distributions were analyzed via Avizo software and in‐house developed MATLAB scripts. The pore size and corresponding volume distributions suggested that mesoscale pores (2‐50 nm) were abundant in the samples but they contributed limitedly to the total pore volume. Macropores (>50 nm) accounted for a small proportion but they had a greater contribution to the overall pore space volume. The coordination numbers of the subject four samples were mainly 0 and 1, which means that isolated pores accounted for the vast majority of the pores. These observations are critical to conduct reliable petrophysical simulations in the oil shales and understand their intrinsic properties accurately.

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Section: Resultsmentioning

confidence: 99%

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

Zhao

Dong

Zhang

et al. 2020

Energy Science & Engineering

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“…In order to quantitatively compare the differences in pore systems of the generated models, the distributions of pore and throat, as well as the coordination number, are computed using the generalized network extraction technique (Raeini et al, 2017;Wu, Tahmasebi, Lin, Jawad Munawar, & Cnudde, 2019). The results are displayed in Figure 8.…”

Section: Characterization Of Shale Modelsmentioning

confidence: 99%

Pore‐Scale 3D Dynamic Modeling and Characterization of Shale Samples: Considering the Effects of Thermal Maturation

Tahmasebi

et al. 2020

JGR Solid Earth

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The development of shale gas necessitates accurate modeling and characterization of these complicated formations, at both small and large scales. At the small scale, the studies based on experimental techniques have uncovered that the components and pore types in shales vary dramatically. Several pore types are identified and varied when the thermal maturation of shales changes. Therefore, accurate modeling and characterization of shale samples require taking such dynamic variations into consideration. This study presents a novel, dynamic, and three-dimensional (3D) modeling technique considering pore-system variation when the thermal maturation changes. The technique can construct dynamic shale models based on quartet structure generation set algorithm and morphological operation. This method can include various elements available in the shale samples in a very accurate way when the dynamic processes are reproduced. To evaluate the performance of the presented technique, 12 dynamic 3D shale models of three cases are constructed. These models are then characterized by analyzing the fractions of components and pores, pore and throat size distributions, coordination number distribution, fractal dimension, and tortuosity. Besides, gas transport in these dynamic 3D shale models is also simulated using pore network modeling to demonstrate the permeability variation of these models. Moreover, the fractions of interparticle and intraparticle pores and cementation degree are changed to further illustrate the capability of the developed algorithm. This study reveals such a dynamic modeling technique is a robust tool to construct various porous media with complicated elements and pores, which is not limited to shale samples. Key Points:• A novel, dynamic, and three-dimensional modeling technique considering pore-system evolution was presented • Generated shale models were characterized by analyzing the geometric, topological, and transport properties of pore systems • The simulation of the gas flow in shale models considers the viscous flow, Knudsen diffusion, and surface diffusion Correspondence to:

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“…Pores and cracks are the main influencing factors of the megascopic mechanical properties, conductivity and permeability of rock [16,17]. Hence, it is very meaningful to identify the pores and cracks in the cross-sectional images, before exploring the microscopic damage law of altered granite.…”

Section: Threshold Segmentationmentioning

confidence: 99%

Identification of Microscopic Damage Law of Rocks Through Digital Image Processing of Computed Tomography Images

Zhe¹,

Zhang²,

Zhang³

et al. 2019

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This paper introduces digital image processing (DIP) to geotechnical field, aiming to disclose the microscopic damage law of rocks under cyclic water invasion. Firstly, the altered granite specimens under cyclic water invasion were subjected to computed tomography (CT) scanning, producing cross-sectional images. These images then underwent noise removal and threshold segmentation. The pores and cores, rock foundation, and high-density nodules were identified accurately in the processed images, reflecting the microstructure of the original rock mass. Based on the processed images, the 3D rock cores were reconstructed, and a 200×200×200 representative elementary volume (REV) was extracted from each rock core. The analysis results show that, with the growing number of water invasion cycles, the surface porosity and non-closed surface porosity continued to increase, while the closed surface porosity first increased and then declined. This research lays a theoretical basis for applying the DIP in geotechnical field.

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Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Cited by 78 publications

References 66 publications

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

Pore‐Scale 3D Dynamic Modeling and Characterization of Shale Samples: Considering the Effects of Thermal Maturation

Identification of Microscopic Damage Law of Rocks Through Digital Image Processing of Computed Tomography Images

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