scholarly journals Laboratory Study on the Effect of Fluid Pressurization Rate on Fracture Instability

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xinyao Wang ◽  
Quanchen Gao ◽  
Xiao Li ◽  
Dianzhu Liu
Keyword(s):  
Dominant Role ◽  
Fluid Pressure ◽  
Slip Mode ◽  
Permeability Evolution ◽  
Induced Earthquakes ◽  
Stick Slip ◽  
Pressurization Rate ◽  
Fracture Instability ◽  
Fluid Pressurization ◽  
Fracture Stability

Fluid injection-induced earthquakes have been a scientific and social issue of wide concern, and fluid pressurization rate may be an important inducement. Therefore, a series of stepwise and conventional injection-induced shear tests were carried out under different fluid pressurization rates and effective normal stresses. The results show that the magnitude of fluid pressure is the main factor controlling the initiation of fracture slipping. The contribution of fluid pressure heterogeneity and permeability evolution on the initiation of fracture slipping is different with the increase of fluid pressurization rate. When the fluid pressurization rate is small, permeability evolution plays a dominant role. On the contrary, the fluid pressure heterogeneity plays a dominant role. The increase of fluid pressurization rate may lead to the transition from creep slip mode to slow stick-slip mode. Under the laboratory scale, the fluid pressure heterogeneity causes the coulomb failure stress to increase by about one times than the predicted value at the initiation of fracture slipping, and the coulomb stress increment threshold of 1.65 MPa is disadvantageous to the fracture stability.

Fluid-induced Seismicity Depends on Injection Rate

2021 ◽  
Author(s):  
Georg Dresen ◽  
Lei Wang ◽  
Grzegorz Kwiatek ◽  
Erik Rybacki ◽  
Audrey Bonnelye ◽  
...  
Keyword(s):  
Release Rate ◽  
Seismic Moment ◽  
Injection Rate ◽  
Fault Slip ◽  
Fluid Injection ◽  
Fault Creep ◽  
Stick Slip ◽  
Pressurization Rate ◽  
Seismic Moment Release ◽  
Fluid Pressurization

<p>Fluid injection causes fault slip that is partitioned in aseismic and seismic moment release. EGS stimulation campaigns have shown that in addition to total fluid volume injected also the rates of injection and fluid pressure increase affect seismic moment release. We investigate the effect of injection rate on slip characteristics, strain partitioning and energy budget in laboratory fluid injection experiments on reservoir sandstone samples in a triaxial deformation apparatus equipped with a 16-channel acoustic emission (AE) recording system. We injected fluid in sawcut samples containing a critically stressed fault at different pressurization rates. In general, fluid-induced fault deformation is dominantly aseismic. We find slow stick-slip events are induced at high fluid pressurization rate while steady fault creep occurs in response to low fluid pressurization rate. The released total seismic moment is found to be related to total injected volume, independent of fault slip behavior. Seismic moment release rate of AE is related to measured fault slip velocity. Total potential energy change and fracture energy release rate are defined by fault stiffness and largely independent of injection rate. Breakdown power density scales with slip rate and is significantly higher for fast injection and pressurization rates. The relation between moment release and injected volume is affected by fault slip behavior, characterized by a linear relation for slip at constant rate and fault creep while a cubic relation is evident for unstable and dynamic slip. Our experimental results allow separating a stable pressure-controlled injection phase with low rate of energy dissipation from a run-away phase, where breakdown power is high and cumulative moment release with injected volume is non-linear.</p>

scholarly journals Permeability evolution during fluid-pressure induced shear slip in saw-cut and natural granite fractures

2020 ◽  
Author(s):  
Zhiqiang Li ◽  
Xiaodong Ma ◽  
Xiang-Zhao Kong ◽  
Martin O Saar ◽  
Daniel Vogler
Keyword(s):  
Fluid Pressure ◽  
Permeability Evolution ◽  
Shear Slip

A micromechanically calibrated numerical model reproducing earthquake cycle in the lab

2021 ◽  
Author(s):  
Guilhem Mollon ◽  
Jérôme Aubry ◽  
Alexandre Schubnel
Keyword(s):  
Acoustic Waves ◽  
Granular Matter ◽  
Fluid Pressure ◽  
Triaxial Tests ◽  
Zone Model ◽  
Geophysical Research ◽  
Stick Slip ◽  
Space And Time ◽  
Discrete Part ◽  
The Continuum

<p>In this communication, we present a novel numerical framework which consists in a direct coupling between a discrete micromechanical modelling of rock damaging processes and a continuous modelling of elastic deformation and acoustic waves. It includes a polygon-based conforming Discrete Element Method (DEM) with a cohesive zone model (CZM, [1]) for the discrete part and a meshfree formulation for the continuum part. This framework is applied to the numerical reproduction of sawcut triaxial tests performed in the lab on marble samples under seismogenic conditions [2]. Realistic boundary conditions (in terms of the elasticity of the loading system, of the absorption of the elastic waves and of the fluid pressure applied on the lateral boundaries) are introduced. Constitutive laws (in the continuum part) and micromechanical parameters (in the discrete part) are calibrated by performing independant simulations based on experimental results found in the literature [3].</p><p>Upon loading, this model provides information on the system behavior that nicely complement the experimental data, such as (i) the progressive damaging of the contacting surfaces, leading to the emission of granular matter in the interface, to the formation of a gouge layer, and to a modification of the interface rheology, (ii) the space and time distribution and statistics and the detailed kinematics of the slip events related to the interface evolution, and (iii) the acoustic wave emission and propagation in the medium associated with such events.</p><p>The model shows that, depending on the experimental conditions (confining pressure, loading rate, surface roughness, etc.), and without relying to any prior choice of slip- or rate-dependent friction laws, a large number of sliding regimes can emerge from this system. This includes large stress drops, regular stick-slip, or stable sliding. This model thus provides an unprecedented view of both local and global phenomena at stake during lab earthquakes, at sampling rates in both space and time which remain out of reach for experimental instrumentation.</p><p>[1]. Mollon, G. (2015). “A numerical framework for discrete modelling of friction and wear using Voronoi polyhedrons”, Tribology International, 90, 343-355<br>[2]. Aubry, J. (2019). “Séismes au laboratoire: friction, plasticité et bilan énergétique”, PhD Thesis, Ecole Normale Supérieure.<br>[3]. Fredrich, J. T.; Evans, B. & Wong, T.-F., (1989). “Micromechanics of the brittle to plastic transition in Carrara marble”, Journal of Geophysical Research: Solid Earth, <span></span></p>

scholarly journals The influence of fault reactivation on injection-induced dynamic triggering of permeability evolution

2020 ◽  
Vol 223 (3) ◽  
pp. 1481-1496
Author(s):  
Elif Cihan Yildirim ◽  
Kyungjae Im ◽  
Derek Elsworth
Keyword(s):  
Pore Pressure ◽  
Fluid Pressure ◽  
Fault Reactivation ◽  
Permeability Evolution ◽  
Fracture Permeability ◽  
Permeability Enhancement ◽  
Pressure Pulses ◽  
Fracture Sealing ◽  
Permeability Increase ◽  
Pressure Driven

SUMMARY Mechanisms controlling fracture permeability enhancement during injection-induced and natural dynamic stressing remain unresolved. We explore pressure-driven permeability (k) evolution by step-increasing fluid pressure (p) on near-critically stressed laboratory fractures in shale and schist as representative of faults in sedimentary reservoirs/seals and basement rocks. Fluid is pulsed through the fracture with successively incremented pressure to first examine sub-reactivation permeability response that then progresses through fracture reactivation. Transient pore pressure pulses result in a permeability increase that persists even after the return of spiked pore pressure to the null background level. We show that fracture sealing is systematically reversible with the perturbing pressure pulses and pressure-driven permeability enhancement is eminently reproducible even absent shear slip and in the very short term (order of minutes). These characteristics of the observed fracture sealing following a pressure perturbation appear similar to those of the response by rate-and-state frictional healing upon stress/velocity perturbations. Dynamic permeability increase scales with the pore pressure magnitude and fracture sealing controls the following per-pulse permeability increase, both in the absence and presence of reactivation. However, initiation of the injection-induced reactivation results in a significant increase in the rate of permeability enhancement (dk/dp). These results demonstrate the role of frictional healing and sealing of fractures at interplay with other probable processes in pore pressure-driven permeability stimulation, such as particle mobilization.

Study of a piezo-electric actuated vibratory micro-robot in stick-slip mode and investigating the design parameters

2017 ◽  
Vol 89 (3) ◽  
pp. 1927-1948 ◽  
Author(s):  
Hadi Jalili ◽  
Hassan Salarieh ◽  
Gholamreza Vossoughi
Keyword(s):  
Design Parameters ◽  
Slip Mode ◽  
Stick Slip ◽  
Micro Robot ◽  
Piezo Electric

scholarly journals Maturity of nearby faults influences seismic hazard from hydraulic fracturing

2018 ◽  
Vol 115 (8) ◽  
pp. E1720-E1729 ◽  
Author(s):  
Maria Kozłowska ◽  
Michael R. Brudzinski ◽  
Paul Friberg ◽  
Robert J. Skoumal ◽  
Nicholas D. Baxter ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Fluid Pressure ◽  
Stress Transfer ◽  
Induced Earthquakes ◽  
Geologic History ◽  
B Values ◽  
Pressure Diffusion ◽  
Hydrologic Connections ◽  
Paleozoic Rocks ◽  
High Pressure Injection

Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values < 1, and many post–shut-in earthquakes, versus (ii) shallower earthquakes in Paleozoic rocks ∼400 m below HF, with smaller magnitudes (M < 1), b-values > 1.5, and few post–shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ∼1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.

Partial Meniscectomy Changes Fluid Pressurization in Articular Cartilage in Human Knees

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
M. Kazemi ◽  
L. P. Li ◽  
M. D. Buschmann ◽  
P. Savard
Keyword(s):  
Articular Cartilage ◽  
Knee Joint ◽  
Relaxation Times ◽  
Fluid Pressure ◽  
Partial Meniscectomy ◽  
Loading Conditions ◽  
Support Mechanism ◽  
Fluid Pressurization ◽  
Creep Loading ◽  
Intact Knee

Partial meniscectomy is believed to change the biomechanics of the knee joint through alterations in the contact of articular cartilages and menisci. Although fluid pressure plays an important role in the load support mechanism of the knee, the fluid pressurization in the cartilages and menisci has been ignored in the finite element studies of the mechanics of meniscectomy. In the present study, a 3D fibril-reinforced poromechanical model of the knee joint was used to explore the fluid flow dependent changes in articular cartilage following partial medial and lateral meniscectomies. Six partial longitudinal meniscectomies were considered under relaxation, simple creep, and combined creep loading conditions. In comparison to the intact knee, partial meniscectomy not only caused a substantial increase in the maximum fluid pressure but also shifted the location of this pressure in the femoral cartilage. Furthermore, these changes were positively correlated to the size of meniscal resection. While in the intact joint, the location of the maximum fluid pressure was dependent on the loading conditions, in the meniscectomized joint the location was predominantly determined by the site of meniscal resection. The partial meniscectomy also reduced the rate of the pressure dissipation, resulting in even larger difference between creep and relaxation times as compared to the case of the intact knee. The knee joint became stiffer after meniscectomy because of higher fluid pressure at knee compression followed by slower pressure dissipation. The present study indicated the role of fluid pressurization in the altered mechanics of meniscectomized knees.

Large-Scale Migration Patterns of Wastewater-Induced Earthquakes in the Central U.S.

2020 ◽  
Author(s):  
Lisa Johann ◽  
Serge A. Shapiro
Keyword(s):  
Seismic Hazard ◽  
Large Volume ◽  
Large Scale ◽  
Oil And Gas ◽  
Fluid Pressure ◽  
Element Model ◽  
Strength Distribution ◽  
Correlation Technique ◽  
Induced Earthquakes ◽  
Injection Rates

&lt;p&gt;It is understood that the recent acceleration of seismic event occurrences in Kansas and Oklahoma, U.S., can be connected to the large-volume disposal of wastewater. These highly saline fluids are co-produced with oil and gas and are re-injected under gravity into the highly porous Arbuckle aquifer. Since 2015, injection rates have been decreasing. However, the seismic hazard in that region remains elevated. Furthermore, it has been noticed that some events in Kansas occur far from disposal wells.&lt;/p&gt;&lt;p&gt;To analyse spatio-temporal patterns between the fluid injection and earthquake locations, we applied a time-dependent 2D cross-correlation technique. This reveals a vectorial migration pattern of the seismic events. Whereas early events occur towards the east-sourtheast, later events are located preferably in northeastern direction of large volume injectors. With time, event locations migrate further in that direction. We explain this observation as well as measured Arbuckle pore pressures by a directional pore-fluid pressure diffusion and poroelastic stress propagation. This also follows from our principal two-dimension poroelastic finite element model which is of predictive power and identifies controlling parameters of the observations. These are mainly the permeability of the target injection formation and the seismogenic basement as well as the anisotropic permeability and the critical fault strength distribution. Our results lead to the conclusion that remote locations are destabilised also when injection rates are declining.&lt;/p&gt;&lt;p&gt;Thus, volume reductions may only provide a direct effect to lower earthquake rates locally. However, a state-wide decrease of the seismicity may require longer times such that the seismic hazard due to wastewater disposal induced seismicity may remain for decades.&amp;#160;&lt;/p&gt;

scholarly journals Hysteresis Behavior in the Stick–Slip Mode at the Boundary Friction

2013 ◽  
Vol 56 (6) ◽  
pp. 1019-1026 ◽  
Author(s):  
I. A. Lyashenko ◽  
A. V. Khomenko ◽  
A. M. Zaskoka
Keyword(s):  
Boundary Friction ◽  
Slip Mode ◽  
Stick Slip ◽  
Hysteresis Behavior
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