Fluid-induced aseismic fault slip outpaces pore-fluid migration

Science ◽  
2019 ◽  
Vol 364 (6439) ◽  
pp. 464-468 ◽  
Author(s):  
Pathikrit Bhattacharya ◽  
Robert C. Viesca
Keyword(s):  
Pore Fluid ◽  
Fluid Injection ◽  
Fluid Migration ◽  
Aseismic Slip ◽  
Earthquake Triggering ◽  
Effective Normal Stress ◽  
Shear Rupture ◽  
Stress Changes ◽  
Slip History ◽  
Rupture Model

Earthquake swarms attributed to subsurface fluid injection are usually assumed to occur on faults destabilized by increased pore-fluid pressures. However, fluid injection could also activate aseismic slip, which might outpace pore-fluid migration and transmit earthquake-triggering stress changes beyond the fluid-pressurized region. We tested this theoretical prediction against data derived from fluid-injection experiments that activated and measured slow, aseismic slip on preexisting, shallow faults. We found that the pore pressure and slip history imply a fault whose strength is the product of a slip-weakening friction coefficient and the local effective normal stress. Using a coupled shear-rupture model, we derived constraints on the hydromechanical parameters of the actively deforming fault. The inferred aseismic rupture front propagates faster and to larger distances than the diffusion of pressurized pore fluid.

Exploring Physical Links between Fluid Injection and Nearby Earthquakes: The 2012 Mw 4.8 Timpson, Texas, Case Study

2020 ◽  
Vol 110 (5) ◽  
pp. 2350-2365 ◽  
Author(s):  
Dawid Szafranski ◽  
Benchun Duan
Keyword(s):  
Aftershock Sequence ◽  
Fluid Injection ◽  
Dynamic Rupture ◽  
Predictive Tool ◽  
Dynamic Friction Coefficient ◽  
Effective Normal Stress ◽  
A Value ◽  
Dynamic Rupture Model ◽  
Rupture Model

ABSTRACT In this work, we integrate a fluid-flow model of 3D deformable porous media with a dynamic rupture model of earthquakes in 3D heterogeneous geologic medium. The method allows us to go beyond fault failure potential analyses and to examine how big an earthquake can be if part of a fault reaches failure due to fluid injection. We apply the method to the 17 May 2012 Mw 4.8 Timpson, Texas, earthquake as a case study. The simulated perturbations of pore pressure and stress from wastewater injection at the time of the mainshock are high enough (several MPa) to trigger an earthquake. Dynamic rupture modeling could reproduce the major observations from the Mw 4.8 event, including its size, focal mechanism, and aftershock sequence, and thus building a more convincing physical link between fluid injection and the Mw 4.8 earthquake. Furthermore, parameter space studies of dynamic rupture modeling allow us to place some constraints on fault frictional properties and background stresses. For the Timpson case, we find that a dynamic friction coefficient of ∼0.3, a value of ∼0.1  m for the critical slip distance in the slip-weakening friction law, and uniform effective normal stress are associated with the Timpson earthquake fault. By reproducing main features of the aftershock sequence of the mainshock, we also demonstrate that the method has potential to become a predictive tool for fluid injection design in the future.

Coupling poroelastic stress change and rate-state fault slip models to simulate fluid injection induced seismic and aseismic slip

2020 ◽  
Author(s):  
Yajing Liu ◽  
Alessandro Verdecchia ◽  
Kai Deng ◽  
Rebecca Harrington
Keyword(s):  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Fault Slip ◽  
Stress Change ◽  
Fluid Injection ◽  
Coulomb Stress ◽  
Aseismic Slip ◽  
Injection Wells ◽  
Wastewater Disposal ◽  
Stress Changes

<p>Fluid injection in unconventional hydrocarbon resource exploration can introduce poroelastic stress and pore pressure changes, which in some cases may lead to aseismic slip on pre-existing fractures or faults. All three processes have been proposed as candidates for inducing earthquakes up to 10s of kilometers from injection wells. In this study, we examine their relative roles in triggering fault slip under both wastewater disposal and hydraulic fracturing scenarios. We first present modeling results of poroelastic stress changes on a previously unmapped fault near Cushing, Oklahoma, due to injection at multiple wastewater disposal wells within ~ 10 km of distance, where over 100 small to moderate earthquakes were reported between 2015/09 to 2016/11 including a Mw5.0 event at the end of the sequence. Despite the much larger amplitude of pore pressure change, we find that earthquake hypocenters are well correlated with positive shear stress change, which dominates the regimes of positive Coulomb stress change encouraging failure. Depending on the relative location of the disposal well to the recipient fault and its sense of motion, fluid injection can introduce either positive or negative Coulomb stress changes, therefore promoting or inhibiting seismicity. Our results suggest that interaction between multiple injection wells needs to be considered in induced seismicity hazard assessment, particularly for areas of dense well distributions. Next, we plan to apply the model to simulate poroelastic stress changes due to multi-stage hydraulic fracturing wells near Dawson Creek, British Columbia, where a dense local broadband seismic array has been in operation since 2016. We will investigate the relative amplitudes, time scales, and spatial ranges of pore pressure versus solid matrix stress changes in influencing local seismicity.</p><p>Finally, we have developed a rate-state friction framework for calculating slip on a pre-existing fault under stress perturbations for both the disposal and hydraulic fracturing cases. Preliminary fault slip simulation results suggest that fault response (aseismic versus seismic) highly depends on 1) the relative timing in the intrinsic earthquake cycle (under tectonic loading) when the stress perturbation is introduced, 2) the amplitude of the perturbation relative to the background fault stress state, and 3) the duration of the perturbation relative to the “memory” timescale governed by the rate-state properties of the fault. Our modeling results suggest the design of injection parameters could be critical for preventing the onset of seismic slip.</p>

Dynamic Modeling of Channel Formation During Fluid Injection Into Unconsolidated Formations

SPE Journal ◽  
2015 ◽  
Vol 20 (04) ◽  
pp. 689-700 ◽  
Author(s):  
S.. Ameen ◽  
A. Dahi Taleghani
Keyword(s):  
Preferential Flow ◽  
Volume Fraction ◽  
Injection Pressure ◽  
Internal Erosion ◽  
Fluid Injection ◽  
Critical Threshold ◽  
Model Parameters ◽  
Flow Paths ◽  
Preferential Flow Paths ◽  
Stress Changes

Summary Injectivity loss is a common problem in unconsolidated-sand formations. Injection of water into a poorly cemented granular medium may lead to internal erosion, and consequently formation of preferential flow paths within the medium because of channelization. Channelization in the porous medium might occur when fluid-induced stresses become locally larger than a critical threshold and small grains are dislodged and carried away; hence, porosity and permeability of the medium will evolve along the induced flow paths. Vice versa, flowback during shut-in might carry particles back to the well and cause sand accumulation inside the well, and subsequently loss of injectivity. In most cases, to maintain the injection rate, operators will increase injection pressure and pumping power. The increased injection pressure results in stress changes and possibly further changes in channel patterns around the wellbore. Experimental laboratory studies have confirmed the presence of the transition from uniform Darcy flow to a fingered-pattern flow. To predict these phenomena, a model is needed to fill this gap by predicting the formation of preferential flow paths and their evolution. A model based on the multiphase-volume-fraction concept is used to decompose porosity into mobile and immobile porosities where phases may change spatially, evolve over time, and lead to development of erosional channels depending on injection rates, viscosity, and rock properties. This model will account for both particle release and suspension deposition. By use of this model, a methodology is proposed to derive model parameters from routine injection tests by inverse analysis. The proposed model presents the characteristic behavior of unconsolidated formation during fluid injection and the possible effect of injection parameters on downhole-permeability evolution.

Repeating earthquakes follow afterslip gradient in the aftermath of the 16th April 2016 M7.8 Pedernales earthquake in Ecuador

2021 ◽  
Author(s):  
Caroline Chalumeau ◽  
Keyword(s):  
Template Matching ◽  
Earthquake Forecasting ◽  
Double Difference ◽  
Recurrence Time ◽  
Fault Mechanics ◽  
Aseismic Slip ◽  
Earthquake Triggering ◽  
Repeating Earthquakes ◽  
Waveform Cross Correlation ◽  
One Year

<p>Repeating earthquakes are earthquakes that repeatedly break a single, time-invariant fault patch. They are generally associated with aseismic slip, which is thought to load asperities, leading to repeated rupture. Repeating earthquakes are therefore useful tools to study aseismic slip and fault mechanics, with possible applications to earthquake triggering, loading rates and earthquake forecasting.</p><p>In this study, we analyze one year of aftershocks following the 16<sup>th</sup> April 2016 Mw 7.8 Pedernales earthquake in Ecuador to find repeating families, using data recorded by permanent and temporary seismological stations. In our area, seismicity during both the inter-seismic and post-seismic periods has been previously linked to aseismic slip. We calculate waveform cross-correlation coefficients (CC) on all available catalogue events, which we use to sort events into preliminary families, using a minimum CC of 0.95. These events were then stacked and used to perform template-matching on the continuous data. In total, 376 earthquakes were classified into 62 families of 4 to 15 earthquakes, including 8 from the one-year period before the mainshock. We later relocated these earthquakes using a double-difference method, which confirmed that most of them did have overlapping sources.</p><p>Repeating earthquakes seem to concentrate largely around the areas of largest afterslip release, where afterslip gradient is the highest. We also find an increase in the recurrence time of repeating events with time after the mainshock, over the first year of the postseismic period, which highlights a possible timeframe for the afterslip’s deceleration. Our results suggest that while most repeating aftershocks are linked to afterslip release, the afterslip gradient may play a bigger role in determining their location than previously thought.</p>

scholarly journals Spatial and temporal multiplet analysis for identification of dominant fluid migration path at The Geysers geothermal field, California

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Staszek ◽  
Ł. Rudziński ◽  
G. Kwiatek
Keyword(s):  
Temporal Analysis ◽  
Geothermal Field ◽  
Fluid Injection ◽  
Fluid Migration ◽  
Multiple Events ◽  
Spatial And Temporal Analysis ◽  
Hydraulic Conditions ◽  
The Geysers ◽  
Multiplet Analysis

AbstractMultiplet analysis is based on the identification of seismic events with very similar waveforms which are used then to enhance seismological analysis e.g. by precise relocation of sources. In underground fluid injection conditions, it is a tool frequently used for imaging of subsurface fracture system. We identify over 150 repeatedly activated seismic sources within seismicity cluster induced by fluid injection in NW part of The Geysers geothermal field (California). Majority of multiple events (ME) occur along N–S oriented planar structure which we interpret as a fault plane. Remaining ME are distributed along structures interpreted as fractures, forming together a system of interconnected cracks enabling fluid migration. Temporal analysis reveals that during periods of relatively low fluid injection the proportion of ME to non-multiple events is higher than during periods of high injection. Moreover, ME which occur within the fault differ in activity rate and source properties from ME designating the fractures and non-multiple events. In this study we utilize observed differences between ME occurring within various structures and non-multiple events to describe hydraulic conditions within the reservoir. We show that spatial and temporal analysis of multiplets can be used for identification and characterization of dominant fluid migration paths.

A New Technique to Calculate Earthquake Stress Transfer and to Probe the Physics of Aftershocks

2020 ◽  
Vol 110 (2) ◽  
pp. 863-873 ◽  
Author(s):  
Margarita Segou ◽  
Tom Parsons
Keyword(s):  
Stress Reduction ◽  
Regional Scale ◽  
Stress Transfer ◽  
The United States ◽  
Physical Principle ◽  
Static Stress ◽  
Stress Change ◽  
Earthquake Triggering ◽  
Triggered Earthquakes ◽  
Stress Changes

ABSTRACT Coseismic stress changes have been the primary physical principle used to explain aftershocks and triggered earthquakes. However, this method does not adequately forecast earthquake rates and diverse rupture populations when subjected to formal testing. We show that earthquake forecasts can be impaired by assumptions made in physics-based models such as the existence of hypothetical optimal faults and regional scale invariability of the stress field. We compare calculations made under these assumptions along with different realizations of a new conceptual triggering model that features a complete assay of all possible ruptures. In this concept, there always exists a set of theoretical planes that has positive failure stress conditions under a combination of background and coseismic static stress change. In the Earth, all of these theoretical planes may not exist, and if they do, they may not be ready to fail. Thus, the actual aftershock plane may not correspond to the plane with the maximum stress change value. This is consistent with observations that mainshocks commonly activate faults with exotic orientations and rakes. Our testing ground is the M 7.2, 2010 El Mayor–Cucapah earthquake sequence that activated multiple diverse fault populations across the United States–Mexico border in California and Baja California. We carry out a retrospective test involving 748 M≥3.0 triggered earthquakes that occurred during a 3 yr period after the mainshock. We find that a probabilistic expression of possible aftershock planes constrained by premainshock rupture patterns is strongly favored (89% of aftershocks consistent with static stress triggering) versus an optimal fault implementation (35% consistent). Results show that coseismic stress change magnitudes do not necessarily control earthquake triggering, instead we find that the summed background stress and coseismic stress change promotes diverse ruptures. Our model can thus explain earthquake triggering in regions where optimal plane mapping shows coseismic stress reduction.

scholarly journals The 2017 Mw 5.5 Pohang Earthquake, South Korea, and Poroelastic Stress Changes Associated With Fluid Injection

2020 ◽  
Vol 125 (6) ◽  
Author(s):  
H. Lim ◽  
K. Deng ◽  
Y.H. Kim ◽  
J.‐H. Ree ◽  
T.‐R. A. Song ◽  
...  
Keyword(s):  
South Korea ◽  
Fluid Injection ◽  
Stress Changes

Stress Perturbation From Aseismic Slip Drives the Seismic Front During Fluid Injection in a Permeable Fault

2020 ◽  
Vol 125 (7) ◽  
Author(s):  
Nicolas Wynants‐Morel ◽  
Frédéric Cappa ◽  
Louis De Barros ◽  
Jean‐Paul Ampuero
Keyword(s):  
Fluid Injection ◽  
Aseismic Slip

Investigation of Dynamic and Static Effects on Earthquake Triggering Using Different Rate and State Friction Laws and Marmara Simulation

2020 ◽  
Author(s):  
Eyup Sopaci ◽  
Atilla Arda Özacar
Keyword(s):  
Onset Time ◽  
Static Stress ◽  
Fault System ◽  
Dynamic Effects ◽  
Earthquake Triggering ◽  
Dynamic Changes ◽  
System Parameters ◽  
Fault Segment ◽  
Stress Changes ◽  
Rate And State Friction

<p>The clock of an earthquake can be advanced due to dynamic and static changes when a triggering signal is applied to a stress-loading fault. While static effects decrease rapidly with distance, dynamic effects can reach thousands of kilometers away. Therefore, earthquake triggering is traditionally associated to static stress changes at local distances and to dynamic effects at greater scales. However, static and dynamic effects near the triggering signal are often nested, thus identifying which effect dominates, becomes unclear. So far, earthquake triggering has been tested using different rate-and-state friction (RSF) laws utilizing alternative views of friction without much comparison. In this study, the analogy of an earthquake is simulated using single degree of freedom spring-block systems governed with three different RSF laws, namely “Dieterich”, “Ruina” and “Perrin”. First, the fault systems are evolved until they reach a stable limit cycle and then static, dynamic and their combination are applied as triggering signals. During synthetic simulations, effects of the triggering signal parameters (onset time, size, duration and frequency) and the fault system parameters (fault stiffness, characteristic slip distance, direct velocity and time dependent state effects) are tested separately. Our results indicate that earthquake triggering is controlled mainly by the onset time, size and duration of the triggering signal but not much sensitive to the signal frequency. In terms of fault system parameters, the fault stiffness and the direct velocity effect are the critical parameters in triggering processes. Among the tested RSF laws, “Ruina” law is more sensitive than “Dieterich” law to both static and dynamic changes and “Perrin” is apparently the most sensitive law to dynamic changes. Especially, when the triggering onset time is close to an unperturbed failure time (future earthquake), dynamic changes result the largest clock advancement, otherwise, static stress changes are substantially more effective. In the next step, realistic models will be established to simulate the effect of the recent (26 September 2019) Marmara earthquake with Mw=5.7 on the locked Kumburgaz fault segment of the North Anatolian Fault Zone. The triggering earthquake will be simulated by combining the static stress change computed via Coulomb law and the dynamic effects using ground motions recorded at broadband seismic stations within similar distances. Outcomes will help us to better understand the effects of static and dynamic changes on the seismic cycle of the Kumburgaz fault segment, which is expected to break soon with a possibly big earthquake causing damage at the metropolitan area of Istanbul in Turkey.</p>

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