Estimating effective permeability using connectivity and branch length distribution of fracture network

2021 ◽  
Vol 146 ◽  
pp. 104314
Author(s):  
Sivaji Lahiri
Keyword(s):  
Effective Permeability ◽  
Length Distribution ◽  
Branch Length ◽  
Fracture Network

SEEPAGE PROPERTIES OF ROCK FRACTURES WITH POWER LAW LENGTH DISTRIBUTIONS

Fractals ◽  
2019 ◽  
Vol 27 (04) ◽  
pp. 1950057 ◽  
Author(s):  
TONGJUN MIAO ◽  
SUJUN CHENG ◽  
AIMIN CHEN ◽  
YAN XU ◽  
GUANG YANG ◽  
...  
Keyword(s):  
Power Law ◽  
Structural Parameters ◽  
Length Distribution ◽  
Fracture Network ◽  
Analytical Models ◽  
Fracture Density ◽  
Fracture Networks ◽  
Permeability Model ◽  
Fracture Length ◽  
Power Law Exponent

Fractures with power law length distributions abound in nature such as carbonate oil and gas reservoirs, sandstone, hot dry rocks, etc. The fluid transport properties and morphology characterization of fracture networks have fascinated numerous researchers to investigate for several decades. In this work, the analytical models for fracture density and permeability are extended from fractal fracture network to general fracture network with power law length distributions. It is found that the fracture density is related to the power law exponents [Formula: see text] and the area porosity [Formula: see text] of fracture network. Then, a permeability model for the fracture length distribution with general power law exponent [Formula: see text] and the power law exponent [Formula: see text] for fracture length versus aperture is proposed based on the well-known cubic law in individual fracture. The analytical expression for permeability of fractured networks is found to be a function of power law exponents [Formula: see text], area porosity [Formula: see text] of fracture network, and the micro-structural parameters (maximum fracture length [Formula: see text], fracture azimuth [Formula: see text] and fracture dip angle [Formula: see text]). The present model may shed light on the mechanism of seepage in fracture networks with power law length distributions.

Branch length distribution in TREF fractionated polyethylene

Polymer ◽  
2011 ◽  
Vol 52 (12) ◽  
pp. 2661-2666 ◽  
Author(s):  
Ramnath Ramachandran ◽  
Gregory Beaucage ◽  
Douglas McFaddin ◽  
Jean Merrick-Mack ◽  
Vassilios Galiatsatos ◽  
...  
Keyword(s):  
Length Distribution ◽  
Branch Length

scholarly journals A Fractal Model for Characterizing Hydraulic Properties of Fractured Rock Mass under Mining Influence

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xiaoli Liu ◽  
Tao Liang ◽  
Sijing Wang ◽  
Kumar Nawnit
Keyword(s):  
Fractal Dimension ◽  
Rock Mass ◽  
Permeability Coefficient ◽  
Fractured Rock ◽  
Length Distribution ◽  
Fracture Network ◽  
Fractal Model ◽  
Physical Model Test ◽  
Fractured Rock Mass ◽  
Fractal Characteristics

In this paper, two basic assumptions are introduced: (1) The number and length distribution of fractures in fractured rock mass are in accordance with the fractal law. (2) Fluid seepage in the fractures satisfies the cubic law. Based on these two assumptions, the fractal model of parallel seepage and radial seepage in fractured rock mass is established, and the seepage tensor of fracture network which reflects the geometric characteristics and fractal characteristics of fracture network under two kinds of seepage is derived. The influence of fracture geometry and fractal characteristics on permeability is analyzed, and the validity and accuracy of the model are verified by comparing the calculated results of the theoretical model and physical model test. The results show that the permeability coefficient K of fracture network is a function of the geometric (maximum crack length Lmax, fractured horizontal projection length L0, diameter calculation section porosity Φ, fracture strike α, and fracture angle θ) and fractal characteristics (fracture network fractal dimension Df and seepage flow fractal dimension DT). With the increase of fractal dimension Df, the permeability coefficient increases. With the increase of DT, the permeability coefficient decreases rapidly. And the larger the Df (Df>1.5), the greater the change of permeability coefficient K with DT.

scholarly journals Quantitative Assessment of Mouse Mammary Gland Morphology Using Automated Digital Image Processing and TEB Detection

Endocrinology ◽  
2016 ◽  
Vol 157 (4) ◽  
pp. 1709-1716 ◽  
Author(s):  
Silvia Blacher ◽  
Céline Gérard ◽  
Anne Gallez ◽  
Jean-Michel Foidart ◽  
Agnès Noël ◽  
...  
Keyword(s):  
Image Processing ◽  
Mammary Gland ◽  
Digital Image ◽  
Molecular Mechanisms ◽  
Growth Parameters ◽  
Length Distribution ◽  
Branch Length ◽  
Breast Development ◽  
The Impact ◽  
Mammary Gland Morphology

Abstract The assessment of rodent mammary gland morphology is largely used to study the molecular mechanisms driving breast development and to analyze the impact of various endocrine disruptors with putative pathological implications. In this work, we propose a methodology relying on fully automated digital image analysis methods including image processing and quantification of the whole ductal tree and of the terminal end buds as well. It allows to accurately and objectively measure both growth parameters and fine morphological glandular structures. Mammary gland elongation was characterized by 2 parameters: the length and the epithelial area of the ductal tree. Ductal tree fine structures were characterized by: 1) branch end-point density, 2) branching density, and 3) branch length distribution. The proposed methodology was compared with quantification methods classically used in the literature. This procedure can be transposed to several software and thus largely used by scientists studying rodent mammary gland morphology.

Single-nucleotide polymorphisms in rice starch synthase IIa that alter starch gelatinisation and starch association of the enzyme

2005 ◽  
Vol 32 (9) ◽  
pp. 763 ◽  
Author(s):  
Takayuki Umemoto ◽  
Noriaki Aoki
Keyword(s):  
Amino Acid ◽  
Single Nucleotide Polymorphisms ◽  
Oryza Sativa L ◽  
Length Distribution ◽  
Branch Length ◽  
Starch Synthase ◽  
Rice Starch ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Chain Length Distribution

The starch synthase IIa (SSIIa) gene of rice (Oryza sativa L.) has been shown to be the alk gene that controls alkali disintegration of rice grains, although the effects of naturally occurring alk mutant alleles on enzyme function have yet to be determined. We genotyped 60 rice cultivars for two single-nucleotide polymorphisms (SNPs) in rice SSIIa, including one that results in an amino acid substitution. Incorporating data for three other SNPs previously genotyped in rice SSIIa, five haplotypes were found. We analysed the association of these SSIIa haplotypes with the chain-length distribution of amylopectin, the gelatinisation temperature of rice flour, the alkali spreading score, and the starch association of the enzyme. It was determined that two SNPs resulting in amino acid changes close to the C-terminus most likely alter SSIIa both in terms of activity and starch granule association. This in turn alters the branch-length distribution of amylopectin and the gelatinisation properties of starch.

scholarly journals Reconstruction and seepage simulation of a coal pore-fracture network based on CT technology

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252277
Author(s):  
Deji Jing ◽  
Xiangxi Meng ◽  
Shaocheng Ge ◽  
Tian Zhang ◽  
Mingxing Ma ◽  
...  
Keyword(s):  
Coal Seam ◽  
Pore Size ◽  
Coordination Number ◽  
Median Filter ◽  
Fluid Velocity ◽  
Length Distribution ◽  
Fracture Network ◽  
Pore Throat ◽  
Pore Connectivity ◽  
Distribution Ranges

The distribution of multiscale pores and fractures in coal and rock is an important basis for reflecting the capacity of fluid flow in coal seam seepage passages. Accurate extraction and qualitative and quantitative analysis of pore-fracture structures are helpful in revealing the flow characteristics of fluid in seepage channels. The relationship between pore and fracture connectivity can provide a scientific reference for optimizing coal seam water injection parameters. Therefore, to analyse the change in permeability caused by the variability in the coal pore-fracture network structure, a CT scanning technique was used to scan coal samples from the Leijia District, Fuxin. A total of 720 sets of original images were collected, a median filter was used to filter out the noise in the obtained images, and to form the basis of a model, the reconstruction and analysis of the three-dimensional pore-fracture morphology of coal samples were carried out. A pore-fracture network model of the coal body was extracted at different scales. Using the maximum sphere algorithm combined with the coordination number, the effect of different quantitative relationships between pore size and pore throat channel permeability was studied. Avizo software was used to simulate the flow path of fluid in the seepage channels. The change trend of the fluid velocity between different seepage channels was discussed. The results of the pore-fracture network models at different scales show that the pore-fracture structure is nonuniform and vertically connected, and the pores are connected at connecting points. The pore size distribution ranges from 104 μm to 9425 μm. The pore throat channel length distribution ranges from 4206 μm to 48073 μm. The size of the coordination number determines the connectivity and thus the porosity of the coal seam. The more connected pore channels there are, the larger the pore diameters and the stronger the percolation ability. During flow in the seepage channels of the coal, the velocity range is divided into a low-speed region, medium-speed region and high-speed region. The fluid seepage in the coal seam is driven by the following factors: pore connectivity > pore and pore throat dimensions > pore and pore throat structure distribution. Ultimately, the pore radius and pore connectivity directly affect the permeability of the coal seam.

Role of fault and fracture networks to de-risk geological leakage from subsurface energy sites

2021 ◽  
Author(s):  
Roberto Emanuele Rizzo ◽  
Hossein Fazeli ◽  
Florian Doster ◽  
Niko Kampman ◽  
Kevin Bisdom ◽  
...  
Keyword(s):  
Carbon Capture ◽  
Fracture Stress ◽  
Effective Permeability ◽  
Co2 Storage ◽  
Carbon Capture And Storage ◽  
Fracture Network ◽  
Natural Fracture ◽  
Single Fracture ◽  
Fracture Networks ◽  
Geological Co2 Storage

<p>The success of geological carbon capture and storage projects depends on the integrity of the top seal, confining injected CO<sub>2</sub> in the subsurface for long periods of time. Here, faults and related fracture networks can compromise sealing by providing an interconnected pathway for injected fluids to reach overlying aquifers or even the surface or sea bottom. In this work, we apply an integrated workflow [1] that, combining single fracture stress-permeability laboratory measurements and detailed fault and fracture network outcrop data, builds permeability models of naturally faulted caprock formations for in situ stress conditions.</p><p>We focus our study on two-dimensional (2D) fault-related fracturing within caprock sequences cut by extensional faults. 2D data of fault and fracture networks were collected from an Upper Jurassic to Lower Cretaceous shale-dominated succession in the Konusdalen area (Nordenskioldland, Svalbard, Norway). The studied rock succession represents the regional caprock and seal for the reservoir of the nearby Longyearbyen CO<sub>2</sub> Lab. By digitising all the visible features over the images and then inputting them into the open-source toolbox FracPaQ [2], we obtain information about the fault and fracture networks. In particular, we study the variations in fracture size (i.e., length, height) and density distribution near and away from the fault zone(s), together with the connectivity of fractures within the network. These three parameters are fundamental to establish if the network provides permeable pathways. They also enable us to statistically reproduce and upscale a fracture network in a realistic way.</p><p>Combining laboratory single fracture stress-permeability measurements with outcrop fracture network data allow us to create an accurate coupled mechanical-hydromechanical model of the natural fracture network and to evaluate the effective permeability of a fault related fracture network. These results are also compared against analytical estimates of effective permeability [3]. With this workflow, we overcome the geometrical simplifications of synthetic fracture models, thus allowing us to establish representative stress-permeability relationships for fractured seals of geological CO2 storage.</p><p>Reference: [1] March et al., 2020, Preprint; [2] Healy et al., 2017, JSG; [3] Seavik & Nixon, 2017, WRR</p>

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