scholarly journals A Two-Dimensional Partitioning of Fracture–Matrix Flow in Fractured Reservoir Rock Using a Dual-Porosity Percolation Model

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2209
Author(s):  
Jinhui Liu ◽  
Yuli Zhou ◽  
Jianguo Chen
Keyword(s):  
Fractured Rocks ◽  
Gas Flow ◽  
Gas Permeability ◽  
Porous Matrix ◽  
Percolation Model ◽  
Dual Porosity ◽  
Two Dimensional ◽  
Fracture Density ◽  
Matrix Permeability ◽  
Matrix Flow

Fractures and micropores have varying contributions to the gas permeability of fractured reservoirs. The quantification of the contribution of fractures and micropores that form a dual-porosity system for gas permeability is critical when attempting to accurately evaluate gas production. However, due to insufficient knowledge of fracture–matrix flow partitioning in such dual-porosity systems, it is challenging for previous models to quantitatively characterize the fracture heterogeneity and accurately evaluate the gas flow and permeability in fractured rocks. In this study, we propose a dual-porosity percolation model to quantitatively investigate the contributions of fractures and matrix micropores towards the gas permeability of fractured rocks. Using percolation theory, we establish fracture networks with complex heterogeneity, which are characterized by various fracture densities and percolation probabilities within a porous matrix with various fracture/matrix permeability ratios. The compressible Navier–Stokes and Brinkman equations were adopted to describe the gas flow in the fractures and porous matrix, respectively. The simulation results indicate that the gas permeability of the dual-porosity system has an exponential relationship with the fracture density and matrix permeability. The contribution of fractures and matrix micropores toward gas permeability can be classified by establishing a two-dimensional partitioning of the fracture–matrix flow related to the fracture heterogeneity and fracture/matrix permeability ratio. The contribution of matrix micropores cannot be neglected if the fracture density is lower than a critical value.

scholarly journals A dual porosity model of high-pressure gas flow for geoenergy applications

2018 ◽  
Vol 55 (6) ◽  
pp. 839-851 ◽  
Author(s):  
L.J. Hosking ◽  
H.R. Thomas ◽  
M. Sedighi
Keyword(s):  
High Pressure ◽  
Carbon Sequestration ◽  
Mass Exchange ◽  
Gas Flow ◽  
Gas Transport ◽  
Fracture Network ◽  
Porous Matrix ◽  
Transport Processes ◽  
Dual Porosity ◽  
Geological Carbon Sequestration

This paper presents the development of a dual porosity numerical model of multiphase, multicomponent chemical–gas transport using a coupled thermal, hydraulic, chemical, and mechanical formulation. Appropriate relationships are used to describe the transport properties of nonideal, reactive gas mixtures at high pressure, enabling the study of geoenergy applications such as geological carbon sequestration. Theoretical descriptions of the key transport processes are based on a dual porosity approach considering the fracture network and porous matrix as distinct continua over the domain. Flow between the pore regions is handled using mass exchange terms and the model includes equilibrium and kinetically controlled chemical reactions. A numerical solution is obtained with a finite element and finite difference approach and verification of the model is pursued to build confidence in the accuracy of the implementation of the dual porosity governing equations. In the course of these tests, the time-splitting approach used to couple the transport, mass exchange, and chemical reaction modules is shown to have been successfully applied. It is claimed that the modelling platform developed provides an advanced tool for the study of high-pressure gas transport, storage, and displacement for geoenergy applications involving multiphase, multicomponent chemical–gas transport in dual porosity media, such as geological carbon sequestration.

Deposition of particles in a two-dimensional lattice gas flow

1992 ◽  
Vol 68 (13) ◽  
pp. 2027-2030 ◽  
Author(s):  
Jean-Christophe Toussaint ◽  
Jean-Marc Debierre ◽  
Loïc Turban
Keyword(s):  
Gas Flow ◽  
Lattice Gas ◽  
Two Dimensional ◽  
Dimensional Lattice

TRIGGERING OF DETONATION PROCESSES IN PROPULSION CHAMBER

2021 ◽  
Vol 14 (2) ◽  
pp. 40-45
Author(s):  
D. V. VORONIN ◽  
Keyword(s):  
Thermal Conductivity ◽  
Numerical Modeling ◽  
Gas Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Chemically Reacting ◽  
Plane Disk ◽  
And Diffusion

The Navier-Stokes equations have been used for numerical modeling of chemically reacting gas flow in the propulsion chamber. The chamber represents an axially symmetrical plane disk. Fuel and oxidant were fed into the chamber separately at some angle to the inflow surface and not parallel one to another to ensure better mixing of species. The model is based on conservation laws of mass, momentum, and energy for nonsteady two-dimensional compressible gas flow in the case of axial symmetry. The processes of viscosity, thermal conductivity, turbulence, and diffusion of species have been taken into account. The possibility of detonation mode of combustion of the mixture in the chamber was numerically demonstrated. The detonation triggering depends on the values of angles between fuel and oxidizer jets. This type of the propulsion chamber is effective because of the absence of stagnation zones and good mixing of species before burning.

Micro-Scale Flow Simulations and Permeability Estimation of Cleat Networks in Coal

2016 ◽  
Vol 846 ◽  
pp. 42-47
Author(s):  
J. Busse ◽  
S. Galindo Torres ◽  
Alexander Scheuermann ◽  
L. Li ◽  
D. Bringemeier
Keyword(s):  
Gas Flow ◽  
Structural Information ◽  
Porous Matrix ◽  
Groundwater Levels ◽  
Micro Scale ◽  
Wide Range ◽  
Boltzmann Method ◽  
The Impact ◽  
Flow Experiments

Coal mining raises a number of environmental and operational challenges, including the impact of changing groundwater levels and flow patterns on adjacent aquifer and surface water systems. Therefore it is of paramount importance to fully understand the flow of water and gases in the geological system on all scales. Flow in coal seams takes place on a wide range of scales from large faults and fractures to the micro-structure of a porous matrix intersected by a characteristic cleat network. On the micro-scale these cleats provide the principal source of permeability for fluid and gas flow. Description of the behaviour of the flow within the network is challenging due to the variations in number, sizing, orientation, aperture and connectivity at a given site. This paper presents a methodology to simulate flow and investigate the permeability of fractured media. A profound characterization of the geometry of the cleat network in micrometer resolution can be derived by CT-scans. The structural information is fed into a Lattice Boltzmann Method (LBM) based model that allows the implementation of virtual flow experiments. With the application of suitable hydraulic boundary conditions the full permeability tensor can be calculated in 3D.

Two-dimensional model of reactive gas flow in a diamond film CVD reactor

1995 ◽  
Vol 4 (8) ◽  
pp. 1065-1068 ◽  
Author(s):  
Y.A. Mankelevich ◽  
A.T. Rakhimov ◽  
N.V. Suetin
Keyword(s):  
Diamond Film ◽  
Gas Flow ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model ◽  
Reactive Gas

Steady small-disturbance transonic dense gas flow past two-dimensional compression/expansion ramps

2018 ◽  
Vol 848 ◽  
pp. 756-787 ◽  
Author(s):  
A. Kluwick ◽  
E. A. Cox
Keyword(s):  
Gas Dynamics ◽  
Gas Flow ◽  
External Forcing ◽  
Two Dimensional ◽  
Small Disturbance ◽  
Dense Gas ◽  
Dimensional Flow ◽  
Flow Past ◽  
Two Dimensional Flow ◽  
Dimensional Parameters

The behaviour of steady transonic dense gas flow is essentially governed by two non-dimensional parameters characterising the magnitude and sign of the fundamental derivative of gas dynamics ($\unicode[STIX]{x1D6E4}$) and its derivative with respect to the density at constant entropy ($\unicode[STIX]{x1D6EC}$) in the small-disturbance limit. The resulting response to external forcing is surprisingly rich and studied in detail for the canonical problem of two-dimensional flow past compression/expansion ramps.

The effect of anisotropic vesiculation on the porous-permeable evolution in magmatic foams

2021 ◽  
Author(s):  
Jenny Schauroth ◽  
Joshua Weaver ◽  
Jackie E. Kendrick ◽  
Anthony Lamur ◽  
Yan Lavallée
Keyword(s):  
Percolation Threshold ◽  
Gas Flow ◽  
Gas Permeability ◽  
Dominant Mode ◽  
Porous Network ◽  
Near Surface ◽  
Shape Distribution ◽  
Aspect Ratios ◽  
Anisotropic Expansion ◽  
The Impact

<p>Volcanoes can undergo rapid transitions between effusive and explosive eruptions that are often dependant on the melt’s ability to devolatilise and outgas. Eruptive products show widely contrasting permeability values for a given porosity owing to the fact that magma properties evolve over time and space, hence porosity and permeability vary depending on transport and deformation history, scale and orientation. The vesicularity that enables bubble coalescence and permeability development, termed the percolation threshold, is experimentally determined to be at ~30-80 %, depending on the microstructure of magma (i.e. bubble size and shape distribution, crystal content, dominant mode of rheological deformation during vesiculation and flow). During ascent of magma pressure decreases and the magma adapts to these new conditions by vesiculating and expanding against wall rocks. Friction between the vesicular magma and the conduit wall encourages shear, which modifies the architecture of the vesicular network. The geometrical constriction associated with conduits, dykes or fractures which host magma thus prevents or limits the isotropic growth of vesicles; we hypothesise that geometrical constraints instead lead to different ratios of isotropic to anisotropic expansion, which impacts vesicle coalescence and the onset and development of permeable gas flow in magma. We present experimental results detailing the impact of constricting geometry on the development of a permeable porous network, by combining various diameter basalt crucibles with different sized cylindrical cores of aphyric rhyolitic glass (0.12 wt.% H<sub>2</sub>O). We vesiculate the samples in a furnace at 1009 °C for different isothermal dwell increments, before cooling our sample assembly and determining porosity, strain and gas permeability. The vesiculated rhyolites host an impervious glass rind (due to near-surface bubble resorption via diffusion) surrounding a vesicular core; as such, we measure gas permeability of the assembly after cutting the upper and lower glassy rind, to expose the permeability of the internal porous network developed experimentally. The findings indicate that increasing anisotropy, caused by minimising the extent of isotropic vesiculation and maximising vesiculation under constricted conditions, lowers the porosity at which the percolation threshold occurs by ~30 %. We postulate that pure and simple shear, developed parallel to the constricting walls, increase bubble aspect ratios and enhance coalescence. This suggests magmatic foams form connected networks at lower porosities when they vesiculate in constricted conduits, dykes and fractures, thus impacting outgassing efficiency. This implies that the physico-chemical evolution of vesiculating magma may be more strongly linked to structural and rheological controls than previously anticipated, with important implications on ascending magma evolution and eruptive processes, such as degassing, outgassing and fragmentation.</p>

scholarly journals Geological Model of a Storage Complex for a CO2 Storage Operation in a Naturally-Fractured Carbonate Formation

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 354 ◽  
Author(s):  
Yann Le Gallo ◽  
José de Dios
Keyword(s):  
Co2 Storage ◽  
Advanced Characterization ◽  
Fracture Network ◽  
Geological Model ◽  
Fracture Density ◽  
Deep Saline Aquifer ◽  
Matrix Permeability ◽  
Carbonate Formation ◽  
Naturally Fractured ◽  
Fractured Carbonate

Investigation into geological storage of CO2 is underway at Hontomín (Spain). The storage reservoir is a deep saline aquifer formed by naturally fractured carbonates with low matrix permeability. Understanding the processes that are involved in CO2 migration within these formations is key to ensure safe operation and reliable plume prediction. A geological model encompassing the whole storage complex was established based upon newly-drilled and legacy wells. The matrix characteristics were mainly obtained from the newly drilled wells with a complete suite of log acquisitions, laboratory works and hydraulic tests. The model major improvement is the integration of the natural fractures. Following a methodology that was developed for naturally fractured hydrocarbon reservoirs, the advanced characterization workflow identified the main sets of fractures and their main characteristics, such as apertures, orientations, and dips. Two main sets of fracture are identified based upon their mean orientation: North-South and East-West with different fracture density for each the facies. The flow capacity of the fracture sets are calibrated on interpreted injection tests by matching their permeability and aperture at the Discrete Fracture Network scale and are subsequently upscaled to the geological model scale. A key new feature of the model is estimated permeability anisotropy induced by the fracture sets.

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