scholarly journals Study on Stress-Dependent Permeability of Fracture Networks in Fractured Porous Media

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Yueli Feng ◽  
Yuetian Liu ◽  
Gang Lei
Keyword(s):  
Porous Media ◽  
Analytical Model ◽  
Effective Stress ◽  
Principal Direction ◽  
Fractured Porous Media ◽  
Fracture Aperture ◽  
Fracture Networks ◽  
Equivalent Permeability ◽  
Principal Value ◽  
Stress Dependent

In order to investigate the stress-sensitive characteristics of fracture networks under reservoir actual stress condition and its influence on the seepage in fractured porous media, we carried out permeability tests on experimental models with fracture networks under constant-volume boundary condition. In addition, a novel analytical stress-dependent permeability model of fracture networks in different directions was derived. Based on the test results and the proposed analytical model, the effects of various parameters (e.g., initial fracture aperture, fluid pressure, rock elastic modulus, effective-stress coefficient, and fracture dip) on deformation characteristics of fracture networks and the corresponding permeability tensor of fracture networks were studied. The research results show that, for a fractured porous media with a single group of fractures, the principal value of permeability is always parallel to the fracture-development direction. With increasing effective stress, the principal value of permeability decreases; however, the principal value direction remains unchanged. Moreover, for the fractured porous media with multiple sets of fractures, the principal direction of equivalent permeability will be inclined to the fractures with larger fracture aperture. Specifically, for the fractured porous media with two sets of intersecting fractures, the principal direction of equivalent permeability is parallel to the angular bisector of these two sets of intersecting fractures. Furthermore, the greater the difference of the fracture aperture change rate under effective stress, the more obvious the deviation of the permeability principal direction. The derived analytical model is of great theoretical and scientific significance to deepen the understanding of the stress-sensitive permeability of fractured reservoirs.

scholarly journals Modelling stress-dependent single and multi-phase flows in fractured porous media based on an immersed-body method with mesh adaptivity

2018 ◽  
Vol 103 ◽  
pp. 229-241 ◽  
Author(s):  
A. Obeysekara ◽  
Q. Lei ◽  
P. Salinas ◽  
D. Pavlidis ◽  
J. Xiang ◽  
...  
Keyword(s):  
Porous Media ◽  
Fractured Porous Media ◽  
Mesh Adaptivity ◽  
Stress Dependent ◽  
Multi Phase ◽  
Body Method

Pressure-Transient Behaviors of Wells in Fractured Reservoirs With Natural- and Hydraulic-Fracture Networks

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 375-394 ◽  
Author(s):  
Zhiming Chen ◽  
Xinwei Liao ◽  
Wei Yu ◽  
Kamy Sepehrnoori
Keyword(s):  
Porous Media ◽  
Fractured Reservoirs ◽  
Fractured Porous Media ◽  
Fracture Networks ◽  
Computationally Efficient ◽  
Efficient Manner ◽  
Complex Fracture ◽  
Mesh Free ◽  
Petroleum Resources ◽  
Fluid Production

Summary Fracture networks are extremely important for the management of groundwater, carbon sequestration, and petroleum resources in fractured reservoirs. Numerous efforts have been made to investigate transient behaviors with fracture networks. Unfortunately, because of the complexity and the arbitrary nature of fracture networks, it is still a challenge to study transient behaviors in a computationally efficient manner. In this work, we present a mesh-free approach to investigate transient behaviors in fractured media with complex fracture networks. Contributions of properties and geometries of fracture networks to the transient behaviors were systematically analyzed. The major findings are noted: There are approximately eight transient behaviors in fractured porous media with complex fracture networks. Each behavior has its own special features, which can be used to estimate the fluid front and quantify fracture properties. Geometries of fracture networks have important impacts on the occurrence and the duration of some transient behaviors, which provide a tool to identify the fracture geometries. The fluid production in the fractured porous media is improved with high-conductivity (denser, larger) and high-complexity fracture networks.

scholarly journals Seismic attenuation in fractured porous media: insights from a hybrid numerical and analytical model

2015 ◽  
Vol 12 (2) ◽  
pp. 210-219 ◽  
Author(s):  
A M Ekanem ◽  
X Y Li ◽  
M Chapman ◽  
I G Main
Keyword(s):  
Porous Media ◽  
Analytical Model ◽  
Seismic Attenuation ◽  
Fractured Porous Media

scholarly journals THEORETICAL AND EXPERIMENTAL STUDY ON STRESS-DEPENDENCY OF OIL–WATER RELATIVE PERMEABILITY IN FRACTAL POROUS MEDIA

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840010 ◽  
Author(s):  
GANG LEI ◽  
SHAOYUAN MO ◽  
ZHENZHEN DONG ◽  
CAI WANG ◽  
WEIRONG LI
Keyword(s):  
Porous Media ◽  
Theoretical Model ◽  
Relative Permeability ◽  
Effective Stress ◽  
Deformation Behavior ◽  
Coupled Flow ◽  
Two Phase ◽  
Irreducible Water Saturation ◽  
Flow Deformation ◽  
Stress Dependent

The coupled flow deformation behavior in the porous media has drawn tremendous attention in various scientific and engineering fields. It is reported that the porous media will be compressed and relative permeability in porous media will be changed as the effective stress increases. However, previous studies provided contradictory evidence for the stress-dependent irreducible water saturation and stress-dependent relative permeability. Until now, appropriate stress-dependent relative permeability curve for two-phase flow through porous media remains unclear. The goal of this work was to theoretically and experimentally study the stress-dependent relative permeability. Laboratory sample flooding tests were conducted to measure two-phase relative permeability in porous media under changing effective stress, and a corresponding theoretical model of stress-dependent relative permeability was derived to interpret the experimental results. The predictions from the proposed analytical model exhibited similar variation trends as the experimental data, which verified the theoretical model. Though the results for the stress-dependent relative permeability from previous studies are different, or even opposite, our proposed model with different conditions can provide explanations to these different results. This work provides a comprehensive experimental and theoretical study of stress-dependent relative permeability in porous media, which is beneficial to accurate performance forecasts for the coupled flow deformation behavior in porous media.

scholarly journals Stress-Dependent Pore Deformation Effects on Multiphase Flow Properties of Porous Media

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Amir H. Haghi* ◽  
Richard Chalaturnyk ◽  
Stephen Talman
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Multiphase Flow ◽  
Capillary Pressure ◽  
Relative Permeability ◽  
Effective Stress ◽  
Core Flooding ◽  
Flow Properties ◽  
Micro Scale ◽  
Stress Dependent

Abstract Relative permeability and capillary pressure are the governing parameters that characterize multiphase fluid flow in porous media for diverse natural and industrial applications, including surface water infiltration into the ground, CO2 sequestration, and hydrocarbon enhanced recovery. Although the drastic effects of deformation of porous media on single-phase fluid flow have been well established, the stress dependency of flow in multiphase systems is not yet fully explored. Here, stress-dependent relative permeability and capillary pressure are studied in a water-wet carbonate specimen both analytically using fractal and poroelasticity theory and experimentally on the micro-scale and macro-scales by means of X-ray computed micro-tomography and isothermal isotropic triaxial core flooding cell, respectively. Our core flooding program using water/N2 phases shows a systematic decrease in the irreducible water saturation and gas relative permeability in response to an increase in effective stress. Intuitively, a leftward shift of the intersection point of water/gas relative permeability curves is interpreted as an increased affinity of the rock to the gas phase. Using a micro-scale proxy model, we identify a leftward shift in pore size distribution and closure of micro-channels to be responsible for the abovementioned observations. These findings prove the crucial impact of effective stress-induced pore deformation on multiphase flow properties of rock, which are missing from the current characterizations of multiphase flow mechanisms in porous media.

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