Evolution of contact area and aperture during the shearing process of natural rock fractures

2021 ◽  
pp. 106236
Author(s):  
M.A. Pirzada ◽  
M. Bahaaddini ◽  
O. Moradian ◽  
H. Roshan
Keyword(s):  
Contact Area ◽  
Rock Fractures ◽  
Natural Rock

Laboratory investigation of nonlinear flow characteristics through natural rock fractures

2019 ◽  
Vol 52 (4) ◽  
pp. 519-528
Author(s):  
Mohammad Javad Nasri Fakherdavood ◽  
Ahmad Ramezanzadeh ◽  
Human Jenabi
Keyword(s):  
Laboratory Investigation ◽  
Flow Characteristics ◽  
Nonlinear Flow ◽  
Rock Fractures ◽  
Natural Rock

Nonlinear flow behavior through rough-walled rock fractures: The effect of contact area

2018 ◽  
Vol 102 ◽  
pp. 179-195 ◽  
Author(s):  
Feng Xiong ◽  
Qinghui Jiang ◽  
Zuyang Ye ◽  
Xiaobo Zhang
Keyword(s):  
Contact Area ◽  
Flow Behavior ◽  
Nonlinear Flow ◽  
Rock Fractures ◽  
Nonlinear Flow Behavior

Closure Behaviour of Natural Rock Fractures

AAPG Bulletin ◽  
2000 ◽  
Vol 84 ◽  
Author(s):  
DUAN, YUTING, Imperial College
Keyword(s):  
Rock Fractures ◽  
Natural Rock

scholarly journals Relating Hydraulic-Electrical-Elastic Properties of Natural Rock Fractures at Elevated Stress and Associated Transient Changes of Fracture Flow

2021 ◽  
Author(s):  
Kazuki Sawayama ◽  
Takuya Ishibashi ◽  
Fei Jiang ◽  
Takeshi Tsuji ◽  
Yasuhiro Fujimitsu
Keyword(s):  
Elastic Properties ◽  
Fracture Flow ◽  
Rock Fractures ◽  
Natural Rock

scholarly journals Relating Hydraulic-Electrical-Elastic Properties of Natural Rock Fractures at Elevated Stress and Associated Transient Changes of Fracture Flow

2021 ◽  
Author(s):  
Kazuki Sawayama ◽  
Takuya Ishibashi ◽  
Fei Jiang ◽  
Takeshi Tsuji ◽  
Yasuhiro Fujimitsu
Keyword(s):  
Elastic Properties ◽  
Fracture Flow ◽  
Rock Fractures ◽  
Natural Rock

scholarly journals Relating Hydraulic–Electrical–Elastic Properties of Natural Rock Fractures at Elevated Stress and Associated Transient Changes of Fracture Flow

2021 ◽  
Vol 54 (5) ◽  
pp. 2145-2164
Author(s):  
K. Sawayama ◽  
T. Ishibashi ◽  
F. Jiang ◽  
T. Tsuji ◽  
Y. Fujimitsu
Keyword(s):  
Elastic Wave ◽  
Wave Velocity ◽  
Hydraulic Properties ◽  
Fractured Rock ◽  
Three Dimensional ◽  
Elastic Wave Velocity ◽  
Fracture Flow ◽  
Rock Fractures ◽  
Flow Area ◽  
Natural Rock

AbstractMonitoring the hydraulic properties within subsurface fractures is vitally important in the contexts of geoengineering developments and seismicity. Geophysical observations are promising tools for remote determination of subsurface hydraulic properties; however, quantitative interpretations are hampered by the paucity of relevant geophysical data for fractured rock masses. This study explores simultaneous changes in hydraulic and geophysical properties of natural rock fractures with increasing normal stress and correlates these property changes through coupling experiments and digital fracture simulations. Our lattice Boltzmann simulation reveals transitions in three-dimensional flow paths, and finite-element modeling enables us to investigate the corresponding evolution of geophysical properties. We show that electrical resistivity is linked with permeability and flow area regardless of fracture roughness, whereas elastic wave velocity is roughness-dependent. This discrepancy arises from the different sensitivities of these quantities to microstructure: velocity is sensitive to the spatial distribution of asperity contacts, whereas permeability and resistivity are insensitive to contact distribution, but instead are controlled by fluid connectivity. We also are able to categorize fracture flow patterns as aperture-dependent, aperture-independent, or disconnected flows, with transitions at specific stress levels. Elastic wave velocity offers potential for detecting the transition between aperture-dependent flow and aperture-independent flow, and resistivity is sensitive to the state of connection of the fracture flow. The hydraulic-electrical-elastic relationships reported here may be beneficial for improving geophysical interpretations and may find applications in studies of seismogenic zones and geothermal reservoirs.

scholarly journals A universal elliptical disc (UED) model to represent natural rock fractures

2021 ◽  
Author(s):  
Jun Zheng ◽  
Jichao Guo ◽  
Jiongchao Wang ◽  
Honglei Sun ◽  
Jianhui Deng ◽  
...  
Keyword(s):  
Rock Fractures ◽  
Natural Rock

scholarly journals Relating Hydraulic-Electrical-Elastic Properties of Natural Rock Fractures at Elevated Stress and Associated Transient Changes of Fracture Flow

2020 ◽  
Author(s):  
Kazuki Sawayama ◽  
Takuya Ishibashi ◽  
Fei Jiang ◽  
Takeshi Tsuji ◽  
Yasuhiro Fujimitsu
Keyword(s):  
Elastic Properties ◽  
Fracture Flow ◽  
Rock Fractures ◽  
Natural Rock

scholarly journals Experimental development of low-frequency shear modulus and attenuation measurements in mated rock fractures: Shear mechanics due to asperity contact area changes with normal stress

Geophysics ◽  
2017 ◽  
Vol 82 (2) ◽  
pp. M19-M36 ◽  
Author(s):  
Seth Saltiel ◽  
Paul A. Selvadurai ◽  
Brian P. Bonner ◽  
Steven D. Glaser ◽  
Jonathan B. Ajo-Franklin
Keyword(s):  
Shear Modulus ◽  
Normal Stress ◽  
Contact Area ◽  
Fractured Reservoirs ◽  
Low Frequency ◽  
Real Contact Area ◽  
Rock Fractures ◽  
Asperity Contact ◽  
Experimental Development ◽  
Real Contact

Reservoir core measurements can help guide seismic monitoring of fluid-induced pressure variations in tight fractured reservoirs, including those targeted for supercritical [Formula: see text] injection. We have developed the first seismic-frequency “room-dry” measurements of fracture-specific shear stiffness, using artificially fractured standard granite samples with different degrees of mating, a well-mated tensile fracture from a dolomite reservoir core, as well as simple roughened polymethyl methacrylate (PMMA) surfaces. We have adapted a low-frequency (0.01–100 Hz) shear modulus and attenuation apparatus to explore the seismic signature of fractures and understand the mechanics of asperity contacts under a range of normal stress conditions. Our instrument is unique in its ability to measure at low-normal stresses (0.5–20 MPa), simulating “open” fractures in shallow or high-fluid-pressure reservoirs. The accuracy of our instrument is demonstrated by calibration and comparison with ultrasonic measurements and low-frequency direct shear measurements of intact samples from the literature. Pressure-sensitive film was used to measure real contact area of the fracture surfaces. The fractured shear modulus for most of the samples shows an exponential dependence on the real contact area. A simple numerical model, with one bonded circular asperity, predicts this behavior and matches the data for the simple PMMA surfaces. The rock surfaces reach their intact moduli at lower contact area than the model predicts, likely due to more complex geometry. Finally, we apply our results to a linear-slip interface model to estimate reflection coefficients and calculate S-wave time delays due to the lower-wave velocities through the fractured zone. We find that cross-well surveys could detect even well-mated hard-rock fractures, assuming the availability of high-repeatability acquisition systems.

scholarly journals Numerical Investigation on Hydraulic Properties of Artificial-Splitting Granite Fractures during Normal and Shear Deformations

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Feng Xiong ◽  
Qinghui Jiang ◽  
Mingxi Chen
Keyword(s):  
Contact Area ◽  
Hydraulic Properties ◽  
Numerical Results ◽  
Normal Displacement ◽  
Rock Fractures ◽  
Fracture Permeability ◽  
Normal Loading ◽  
New Model ◽  
Hydraulic Aperture ◽  
Mechanical Aperture

This study explores the effects of normal loading and shearing on hydraulic properties in roughness-walled rock fractures. The geometries of five fractures were measured by the 3D scanning technology. The flow simulation was performed for rough rock fractures with large displacements during normal loading and shearing by finite volume method (FVM). The results demonstrate that the deformation of fracture with increasing normal stress and shear causes nonuniform changes in void space geometry and further influences fracture permeability. Associated with normal displacement are an increase in contact area and a decrease in mechanical aperture. The transmissivity is decreasing by 3 orders of magnitude response to applied normal displacement values of 0.0 mm to 1.8 mm. In contrast, an increase in mechanical aperture and contact ratio that occurs with increasing shear displacement values of 0.0 mm to 4.0 mm is associated with decreasing distinctly transmissivity by 1.5–2 orders of magnitude. Based on the numerical results, an empirical equation is proposed to evaluate the effects of contact area and roughness of fracture on the hydraulic aperture. The good agreement between numerical results and the predicted results by the new model indicates that the proposed model is capable of estimating the hydraulic aperture of rock fractures through parametric analyses, compared with other published models from available literature. In addition, the new model succeeds in predicting the transmissivity in Develi and Babadagli (2014) water flow experiments.

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