MODELING OF UNDERSEEPAGE FLOW IN A GROUND FOUNDATION CONSIDERING 3D PARTICLE ARRANGEMENT AND PORE STRUCTURE AND SEEPAGE FLOW CHARACTERISTICS AROUND THE LEVEE TOE

2020 ◽  
Vol 76 (2) ◽  
pp. I_313-I_318
Author(s):  
Katsuyuki KURIHARA ◽  
Kosuke TABATA ◽  
Shoji FUKUOKA
Keyword(s):  
Pore Structure ◽  
Flow Characteristics ◽  
Seepage Flow ◽  
Particle Arrangement

Pore Structure Characterization of Tailing Bed and Dewatering Mechanism at nm-µm Scales Under Shearing

2021 ◽  
Vol 21 (1) ◽  
pp. 354-361
Author(s):  
Hua-Zhe Jiao ◽  
Shu-Fei Wang ◽  
Tian-Rang Jia ◽  
Yi-Wen Ju
Keyword(s):  
Pore Structure ◽  
Fine Particles ◽  
Seepage Flow ◽  
Structure Characterization ◽  
Surface Velocity ◽  
Pore Channel ◽  
Pore Network Model ◽  
Pore Characteristics ◽  
Fine Tailings ◽  
Paste Backfill

The preparation of high-density tailings is a prerequisite for cemented paste backfill technology, and the flocculated fine tailings of sealed water leads to challenges in the slurry thickening of tailings. Shearing conditions can compact the micro floc structure to improve the underflow concentration. The nm-μm scales of pore characteristics and connectivity are essential for the dewatering process. The computed tomography (CT) results show that the underflow concentration increases from 62.3 wt% to 68.6 wt% after undergoing rake shearing at 2 rpm, and the porosity decreases from 42.7% to 35.54%. The shearing conditions reduces the spheres and sticks by 43.14% and 43.3%, respectively, from the pore network model (PNM). The seepage flow states were affected by the changes in the pore structure. The maximum surface velocity and the maximum internal pressure decrease after undergoing shearing. Shearing conditions can break the micro floc structures, and the fine particles can fill in the micron-scale pores by gravity and shearing conditions, resulting in the forced drainage of water into the pores. Shearing conditions can break the thickening floc network structures; natural fine particles can fill the micron-scale pores by gravity and shearing conditions. The upward seepage of sealed water along the μm-scale pore channel causes a higher bed concentration. However, the sealed water in the nm-scale pores cannot flow upward due to water cohesion and particle adhesion resistance.

Study on Micro Pore Structure Characteristics of Carbonate Cores of Low Permeability

2014 ◽  
Vol 1015 ◽  
pp. 129-134
Author(s):  
Pu Fu Xiao ◽  
Zheng Ming Yang ◽  
Ya Pu Zhang ◽  
Chang Cheng Gai
Keyword(s):  
Pore Structure ◽  
Middle Eastern ◽  
Flow Characteristics ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Low Permeability ◽  
Structure Characteristics ◽  
Constant Rate ◽  
Carbonate Cores

In order to understand the characteristics and flow characteristics of the low permeability carbonate reservoir of Middle East, in this paper, we take a Middle Eastern oil field as an example, using constant-rate mercury penetration technique, analyzing the micro pore structure characteristics of carbonate cores. The results show that, the pore radius distribution characteristics of different permeability is similar, mostly between 90-200μm, the peak occur at about 120μm. After that, we get the main factor affecting the reservoir physical quality of carbonate reservoir is throat rather than pore. And compared with the same permeability of sandstone cores, found that even if a poor sorting and strong heterogeneity of carbonate cores, but due to its throat contribution to permeability is very balanced, show the low permeability carbonate difficulty of development smaller than sandstone, only reducing the pore throat ratio, improve the ability of reservoir seepage, can have a good development effect.

scholarly journals A Study on the Seepage Flow Characteristics and Disaster-Causing Mechanism of Collapse Column

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Feisheng Feng ◽  
Suping Peng ◽  
Pingjie Fu ◽  
Wenfeng Du ◽  
Dongjing Xu
Keyword(s):  
Water Flow ◽  
Permeability Coefficient ◽  
Water Inrush ◽  
Particle Diameter ◽  
Flow Characteristics ◽  
Seepage Flow ◽  
Fissure Zone ◽  
Experimental Data Processing ◽  
Water Flow Velocity ◽  
Column Collapse

Factors such as the hydrogeological conditions, the lithological characteristics of the columns’ components, and the lithological characteristics and stress conditions of the coal seam roof and floor are interrelated and jointly affect column collapse. In this study, the disaster-causing mechanism of column collapse was studied. Based on the system theory, a collapsed column is divided into the column and the surrounding fissure zone as two subsystems for analysis. And, the permeability coefficient of the broken rock under different conditions was measured by a self-designed equipment. The variations of the permeability coefficient for rock samples with different particle diameters, different axial pressures Pa, and different seepage velocities were further studied. Through phenomena analysis and experimental data processing, it was concluded that, under the same pressure state, smaller particle diameter meant smaller permeability coefficient; with the increase of axial pressure, the permeability coefficient decreased; and the larger the water flow velocity was, the smaller the permeability coefficient became. For particle diameter Φ = 2.5–5 mm or larger, the tiny particles formed by randomly washing and breaking in the water flow blocked some of the channels. For particle diameters smaller than Φ = 2.5–5 mm, the smaller permeability coefficient was attributed to the turbulence resulting from non-Darcy flow. The study on the permeability of the fractured rock mass clarified the mechanism of water inrush from the fissure zone of the collapsed column: the collapsed column itself was impermeable, and the permeability of the fissure zone around the collapsed column was related to the lithological characteristics of the rock within the fissure zone and the sequencing of rock strata. When mining coal in areas with collapsed columns, experiments on collapsed columns and fissure zones are prerequisites. This study has a certain referential value for coal mining in this region.

scholarly journals Study on the microscopic pore structures of the four different kinds of lithological reservoirs in the basin of Western China

2021 ◽  
Vol 11 (3) ◽  
pp. 1139-1153
Author(s):  
Tianqi Liu ◽  
Shengchun Xiong ◽  
Jiayi Yu ◽  
Ying He ◽  
Peng Song ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Nitrogen Adsorption ◽  
Seepage Flow ◽  
Western China ◽  
Physical Parameters ◽  
Structure Characteristics ◽  
Micropore Structure ◽  
Testing Technology ◽  
Distribution Laws ◽  
Micropore Size

AbstractIn the basin of western China, four different kinds of lithological reservoirs are developed, including low-permeability sandstone, sedimentary tuff, shale and volcanic rock. There is generally a large difference in the micropore structure characteristics and distribution laws due to different reservoirs. The reserving capacity as well as the porous flowability, mechanism and laws are determined by the micropore structure characteristics and distribution laws of hydrocarbon reservoirs. Low-temperature nitrogen adsorption and desorption technology, high-pressure mercury injection experiment and nuclear magnetic resonance (NMR) testing technology are applied to study the micropore size, quantity, structure and distribution laws of four different kinds of lithological reservoirs as well as their similarities and differences of corresponding relation with macroporosity–permeability physical parameters. This paper also studies the movable fluid and nonlinear seepage flow characteristics of four different kinds of lithological reservoirs.

scholarly journals Permeable Asphalt Hydraulic Conductivity and Particulate Matter Separation With XRT

2021 ◽  
Author(s):  
Mariana Marchioni ◽  
Roberto Fedele ◽  
Anita Raimondi ◽  
John Sansalone ◽  
Gianfranco Becciu
Keyword(s):  
Particulate Matter ◽  
Hydraulic Conductivity ◽  
Pore Structure ◽  
Management Practice ◽  
Flow Characteristics ◽  
Chemical Separation ◽  
Noise Pollution ◽  
Material Behavior ◽  
Rainfall Simulation ◽  
Structure Parameters

Abstract Permeable asphalt (PA) is a composite material with an open graded mix design that provides a pore structure facilitating stormwater infiltration. PA is often used as a wearing course for permeable pavements and on roadways to reduce aquaplaning and noise pollution. The pore structure functions as a filter promoting particulate matter (PM) separation. The infiltrating flow characteristics are predominately dependent on pore diameter and pore interconnectivity. X-Ray microTomography (XRT) has been successfully used to estimate these parameters that are otherwise difficult to obtain through conventional gravimetric methods. The pore structure parameters allow modeling of hydraulic conductivity (k) and filtration mechanisms; required to examine the material behavior for infiltration and PM separation. Pore structure parameters were determined through XTR for three PA mixtures. The Kozeny-Kovàv model was implemented to estimate k. PM separation was tested using a pore-to-PM diameter categorical model. This filtration mechanism model was validated with data using rainfall simulation. The filtration model provided a good correlation between measured and modeled data. The identification of filtration mechanisms and k facilitate the design and evaluation of permeable pavement systems as a best management practice (BMP) for runoff volume and flow as well as PM and PM-partitioned chemical separation.

The Moving Boundary Movement of Vertical Fractured Well in Tight Oil Reservoir

2013 ◽  
Vol 868 ◽  
pp. 633-637
Author(s):  
Li Feng Liu ◽  
Xin Wang
Keyword(s):  
Pressure Gradient ◽  
Flow Model ◽  
Moving Boundary ◽  
Flow Characteristics ◽  
Seepage Flow ◽  
Threshold Pressure ◽  
Threshold Pressure Gradient ◽  
Tight Reservoir ◽  
Tight Reservoirs ◽  
Fractured Well

Because of the obvious non-Darcy characteristic of fluid flowing in tight reservoirs, there is a virtual moving boundary at the flow edge, and these percolation models of fractured wells with Darcy formula are no longer applicable. Based on the threshold pressure gradient effect, the unsteady seepage flow model of vertical fractured well was established in the drain area by means of Source and Green's Functions. With the flow characteristics at the boundary of tight reservoir, the motion equation of axes of moving boundary was obtained. By Example analysis, its proved that the moving boundary is approximate circular in the far-field, and it will move slower with the increase of the threshold pressure gradient.

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