scholarly journals The Influence of Grain Shape and Size on the Relationship Between Porosity and Permeability in Sandstone

2021 ◽  
Author(s):  
Ryan Payton ◽  
Domenico Chiarella ◽  
Andrew Kingdon

An accurate and reliable description of the relationship between porosity and permeability in geological materials is valuable in understanding subsurface fluid movement. This is of great importance for studies of reservoir characterisation, useful for energy exploitation, carbon capture, use and storage (CCUS) and groundwater contamination and remediation. Whilst the relationship between pore characteristics and porosity and permeability are well examined, there is scope for further investigation into the influence of grain characteristics on porosity and permeability due to the inherent relationship between grains and related pores. In this work we use digital image analysis (DIA) of reconstructed 3D X-ray micro computed tomographic (μCT) images to measure porosity, permeability and segment individual grains enabling the measurement of grain shape (sphericity) and size (Feret diameter). We compare two marker-based watershed workflows to grain boundary segmentation before applying the most reliable one to our images. We found there to be a positive relationship between grain sphericity and porosity according to ϕ=1.22ϕs-0.42 whereas no such relationship exists with grain size. We applied our grain shape and size measurements to calculate a Kozeny-Carman (K-C) porosity-permeability fit which was found to be unsatisfactory, possibly due to significant deviation from the K-C assumption that grains are spherical. Therefore, we show that a simpler fit of the form K= 10^5.54 ϕ^3.7, excluding any influence of grain characteristics, is most suitable for the studied materials and that grain shape and size is not influential on the porosity-permeability relationship in a K-C paradigm.

2021 ◽  
Author(s):  
Ryan Payton ◽  
Domenico Chiarella ◽  
Andrew Kingdon

An accurate and reliable description of the relationship between porosity and permeability in geological materials is valuable in understanding subsurface fluid movement. This is of great importance for studies of reservoir characterisation, useful for energy exploitation, carbon capture, use and storage (CCUS) and groundwater contamination and remediation. Whilst the relationship between pore characteristics and porosity and permeability are well examined, there is scope for further investigation into the influence of grain characteristics on porosity and permeability due to the inherent relationship between grains and related pores. In this work we use digital image analysis (DIA) of reconstructed 3D X-ray micro computed tomographic (μCT) images to measure porosity, permeability and segment individual grains enabling the measurement of grain shape (sphericity) and size (Feret diameter). We compare two marker-based watershed workflows to grain boundary segmentation before applying the most reliable one to our images. We found there to be a positive relationship between grain sphericity and porosity according to ϕ=1.22ϕs-0.42 whereas no such relationship exists with grain size. We applied our grain shape and size measurements to calculate a Kozeny-Carman (K-C) porosity-permeability fit which was found to be unsatisfactory, possibly due to significant deviation from the K-C assumption that grains are spherical. Therefore, we show that a simpler fit of the form K= 10^5.54 ϕ^3.7, excluding any influence of grain characteristics, is most suitable for the studied materials and that grain shape and size is not influential on the porosity-permeability relationship in a K-C paradigm.


2021 ◽  
Vol 60 (1) ◽  
pp. 207-215
Author(s):  
Songsong Lian ◽  
Tao Meng ◽  
Hongqi Song ◽  
Zhongjia Wang ◽  
Jiabin Li

Abstract The relationship between percolation mechanism and pore characteristics for recycled permeable bricks with different porosities is investigated in this study based on X-ray computed tomography (X-CT). Permeability coefficients are measured and some characteristics including size, amount, and distribution of the pore are analysed. The results show that the effective porosity and permeability coefficient of the recycled permeable bricks exhibit a linear relationship first and then a quadratic curve relationship, where the critical effective porosity is 12%. Meanwhile, we discovered that nonlinear channels in permeable bricks are larger and fewer compared with linear percolation channels, regardless of whether the percolation stage is linear or nonlinear. Additionally, when the area and number ratios of the linear and nonlinear percolation channels reached 80% and 10%, respectively, the overall percolation state of the permeable bricks changed from linear to nonlinear percolation. This research is helpful to improve the mechanical and percolation properties of recycled concrete bricks and promote the application of porous permeable material.


Author(s):  
O. A. Zadorozhna ◽  
T. P. Shyianova ◽  
M.Yu. Skorokhodov

Seed longevity of 76 spring barley gene pool samples (Hordeum vulgare L. subsp. distichon, convar. distichon: 56 nutans Schubl., two deficience (Steud.) Koern., two erectum Rode ex Shuebl., two medicum Koern.; convar. nudum (L.) A.Trof.: one nudum L. та subsp. vulgare: convar. vulgare: nine pallidum Ser., three rikotense Regel.; convar. coeleste (L.) A.Trof.: one coeleste (L.) A.Trof.) from 26 countries, 11 years and four places of reproduction was analyzed. Seeds with 5–8% moisture content were stored in chamber with unregulated and 4oC temperature. The possibility of seed storage under these conditions for at least 10 years without significant changes in germination has been established. The importance of meteorological conditions in the formation and ripening of seeds for their longevity is confirmed. The relationship between the decrease of barley seeds longevity and storage conditions, amount of rainfall, temperature regime during the growing season of plants is discussed.


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