A risk-based approach for managing hydraulic fracturing–induced seismicity

Science ◽  
2021 ◽  
Vol 372 (6541) ◽  
pp. 504-507
Author(s):  
Ryan Schultz ◽  
Gregory C. Beroza ◽  
William L. Ellsworth
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Red Light ◽  
Maximum Magnitude ◽  
Traffic Light ◽  
Induced Earthquakes ◽  
Eagle Ford Shale ◽  
Eagle Ford ◽  
Sensitivity Tests ◽  
Spatially Varying

Risks from induced earthquakes are a growing concern that needs effective management. For hydraulic fracturing of the Eagle Ford shale in southern Texas, we developed a risk-informed strategy for choosing red-light thresholds that require immediate well shut-in. We used a combination of datasets to simulate spatially heterogeneous nuisance and damage impacts. Simulated impacts are greater in the northeast of the play and smaller in the southwest. This heterogeneity is driven by concentrations of population density. Spatially varying red-light thresholds normalized on these impacts [moment magnitude (Mw) 2.0 to 5.0] are fairer and safer than a single threshold applied over a broad area. Sensitivity tests indicate that the forecast maximum magnitude is the most influential parameter. Our method provides a guideline for traffic light protocols and managing induced seismicity risks.

Experiences and learnings from induced seismicity regulation in Alberta

2018 ◽  
Vol 6 (2) ◽  
pp. SE15-SE21 ◽  
Author(s):  
Todd Shipman ◽  
Ron MacDonald ◽  
Tom Byrnes
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Red Light ◽  
Seismic Hazard Assessment ◽  
Traffic Light ◽  
Regulatory Requirements ◽  
Current State ◽  
New Information ◽  
Response Plan ◽  
The Town

We have examined the experiences and learnings acquired through the implementation of the Alberta Energy Regulator’s (AER) subsurface order no. 2 (sub or no. 2) traffic light protocol (TLP). On 22 January 2015, a 4.4 [Formula: see text] seismic event occurred near a hydraulic fracturing operation in west-central Alberta and was felt by residents of the town of Fox Creek. On 19 February 2015, the AER issued sub or no. 2 to help manage induced seismicity, as related to hydraulic fracturing of the Duvernay zone in a prescribed area around Fox Creek. Sub or no. 2 requires operators affected by the order to conduct a seismic hazard assessment; prepare a monitoring, mitigation, and response plan; conduct seismic monitoring; and adhere to a TLP. Since sub or no. 2 was issued, two “red light” events (i.e., [Formula: see text]) have occurred in the area. Review and analysis of data and information collected under sub or no. 2 facilitate an improved understanding of the key geologic and operational controls on induced seismicity and allow for an assessment of the efficacy of industry practices and regulatory requirements. We still support the use of local magnitude [Formula: see text] for our TLP based on the purpose and outcomes provided by sub or no. 2. Conversations with operators have suggested that [Formula: see text] orientation should inform the wells’ trajectory with respect to critically stressed faults. The requirement of a response plan was part of the learning process developed under sub or no. 2. Through this exercise, the AER has developed a better understanding of the goals of the response plans, which were better defined through conversations with operators. Sub or no. 2 is consistent with the current state of the evolving science of induced seismicity and has the capacity to change as new information is obtained.

scholarly journals Real‐Time Imaging, Forecasting, and Management of Human‐Induced Seismicity at Preston New Road, Lancashire, England

2019 ◽  
Author(s):  
Huw Clarke ◽  
James P. Verdon ◽  
Tom Kettlety ◽  
Alan F. Baird ◽  
J‐Michael Kendall
Keyword(s):  
Hydraulic Fracturing ◽  
Real Time ◽  
Shale Gas ◽  
Statistical Models ◽  
Induced Seismicity ◽  
Red Light ◽  
Fracture Network ◽  
Fluid Injection ◽  
Traffic Light ◽  
Subsurface Fluid

ABSTRACTEarthquakes induced by subsurface fluid injection pose a significant issue across a range of industries. Debate continues as to the most effective methods to mitigate the resulting seismic hazard. Observations of induced seismicity indicate that the rate of seismicity scales with the injection volume and that events follow the Gutenberg–Richter distribution. These two inferences permit us to populate statistical models of the seismicity and extrapolate them to make forecasts of the expected event magnitudes as injection continues. Here, we describe a shale gas site where this approach was used in real time to make operational decisions during hydraulic fracturing operations.Microseismic observations revealed the intersection between hydraulic fracturing and a pre‐existing fault or fracture network that became seismically active. Although “red light” events, requiring a pause to the injection program, occurred on several occasions, the observed event magnitudes fell within expected levels based on the extrapolated statistical models, and the levels of seismicity remained within acceptable limits as defined by the regulator. To date, induced seismicity has typically been regulated using retroactive traffic light schemes. This study shows that the use of high‐quality microseismic observations to populate statistical models that forecast expected event magnitudes can provide a more effective approach.

scholarly journals Green, yellow, red, or out of the blue? An assessment of Traffic Light Schemes to mitigate the impact of hydraulic fracturing-induced seismicity

2020 ◽  
Author(s):  
James P. Verdon ◽  
Julian J. Bommer
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Risk Mitigation ◽  
Red Light ◽  
Fundamental Parameter ◽  
Traffic Light ◽  
The Usa ◽  
The Uk ◽  
The Impact ◽  
Magnitude Increase

Abstract Mitigating hydraulic fracturing-induced seismicity (HF-IS) poses a challenge for shale gas companies and regulators alike. The use of Traffic Light Schemes (TLSs) is the most common way by which the hazards associated with HF-IS are mitigated. In this study, we discuss the implicit risk mitigation objectives of TLSs and explain the advantages of magnitude as the fundamental parameter to characterise induced seismic hazard. We go on to investigate some of the key assumptions on which TLSs are based, namely that magnitudes evolve relatively gradually from green to yellow to red thresholds (as opposed to larger events occurring “out-of-the-blue”), and that trailing event magnitudes do not increase substantially after injection stops. We compile HF-IS datasets from around the world, including the USA, Canada, the UK, and China, and track the temporal evolution of magnitudes in order to evaluate the extent to which magnitude jumps (i.e. sharp increases in magnitude from preceding events within a sequence) and trailing events occur. We find in the majority of cases magnitude jumps are less than 2 units. One quarter of cases experienced a post-injection magnitude increase, with the largest being 1.6. Trailing event increases generally occurred soon after injection, with most cases showing no increase in magnitude more than a few days after then end of injection. Hence, the effective operation of TLSs may require red-light thresholds to be set as much as two magnitude units below the threshold that the scheme is intended to avoid.

Risk-Informed Recommendations for Managing Hydraulic Fracturing–Induced Seismicity via Traffic Light Protocols

2020 ◽  
Vol 110 (5) ◽  
pp. 2411-2422 ◽  
Author(s):  
Ryan Schultz ◽  
Greg Beroza ◽  
William Ellsworth ◽  
Jack Baker
Keyword(s):  
Hydraulic Fracturing ◽  
Ground Motion ◽  
Red Light ◽  
Real Life ◽  
Site Amplification ◽  
Mitigation Strategies ◽  
Traffic Light ◽  
Induced Earthquakes ◽  
Risk Curves ◽  
Do So

ABSTRACT Risks from induced earthquakes caused by hydraulic fracturing are a growing concern with a need for effective management. Here, we develop a risk-informed strategy for choosing red and yellow traffic light thresholds based on the current understanding of induced earthquakes. To do so, we utilize probabilistic maximum magnitudes, magnitude to ground-motion relationships, population densities, statistical distributions of site amplification, and felt or damaging ground-motion thresholds to compute the risk of damage or nuisance. Risk curves for various forecast scenarios highlight two proposed guidelines. First, setting red-light thresholds within the nuisance range of ground motions reduces the chances that runaway earthquakes could cause unacceptable damage. Second, setting yellow-light thresholds approximately two magnitude units less than the red light ensures that operators have a sufficient opportunity to enact mitigation strategies. We compare the differences in risk between several real-life traffic light cases to illustrate how this approach could allow regulators to design traffic light protocols in a risk-informed manner and thus balance the consequences of their decisions more effectively. Our approach also promotes the transparent communication of risk to all involved stakeholders.

Comprehensive Characterization and Mitigation of Hydraulic Fracturing-Induced Seismicity in Fox Creek, Alberta

SPE Journal ◽  
2021 ◽  
pp. 1-12
Author(s):  
Gang Hui ◽  
Shengnan Chen ◽  
Zhangxin Chen ◽  
Fei Gu ◽  
Mathab Ghoroori ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Hydraulic Fracture ◽  
Induced Seismicity ◽  
Mitigation Strategy ◽  
Moment Magnitude ◽  
Induced Earthquakes ◽  
Data Set ◽  
Comprehensive Characterization

Summary The relationships among formation properties, fracturing operations, and induced earthquakes nucleated at distinctive moments and positions remain unclear. In this study, a complete data set on formations, seismicity, and fracturing treatments is collected in Fox Creek, Alberta, Canada. The data set is then used to characterize the induced seismicity and evaluate its susceptibility toward fracturing stimulations via integration of geology, geomechanics, and hydrology. Five mechanisms are identified to account for spatiotemporal activation of the nearby faults in Fox Creek, where all major events [with a moment magnitude (Mw) greater than 2.5] are caused by the increase in pore pressure and poroelastic stress during the fracturing operation. In addition, an integrated geological index (IGI) and a combined geomechanical index (CGI) are first proposed to indicate seismicity susceptibility, which is consistent with the spatial distribution of induced earthquakes. Finally, mitigation strategy results suggest that enlarging a hydraulic fracture-fault distance and decreasing a fracturing job size can reduce the risk of potential seismic activities.

2000-2020: Two Decades of Evolution of Hydraulic Fracturing-Induced Seismicity in the Western Canada Sedimentary Basin

2021 ◽  
Author(s):  
Germán Rodríguez-Pradilla ◽  
David Eaton ◽  
Melanie Popp
Keyword(s):  
Hydraulic Fracturing ◽  
Induced Seismicity ◽  
Sedimentary Basin ◽  
Unit Area ◽  
Critical Parameters ◽  
Seismic Events ◽  
Western Canada ◽  
Maximum Magnitude ◽  
Western Canada Sedimentary Basin ◽  
Canada Sedimentary Basin

Abstract The goal of this work is to calibrate a regional predictive model for maximum magnitude of seismic activity associated with hydraulic-fracturing in low-permeability formations in the Western Canada Sedimentary Basin (WCSB). Hydraulic fracturing data (i.e. total injected volume, injection rate, and pressure) were compiled from more than 40,000 hydraulic-fractured wells in the WCSB. These wells were drilled into more than 100 different formations over a 20-year period (January 1st, 2000 and January 1st, 2020). The total injected volume per unit area was calculated utilizing an area of 0.2° in longitude by 0.1° in latitude (or approximately 13x11km, somewhat larger than a standard township of 6x6 miles). This volume was then used to correlate with reported seismicity in the same unit areas. Collectively, within the 143 km2 area considered in this study, a correlation between the total injected volume and the maximum magnitude of seismic events was observed. Results are similar to the maximum-magnitude forecasting model proposed by A. McGarr (JGR, 2014) for seismic events induced by wastewater injection wells in central US. The McGarr method is also based on the total injected fluid per well (or per multiple nearby wells located in the same unit area). However, in some areas in the WCSB, lower injected fluid volumes than the McGarr model predicts were needed to induce seismic events of magnitude 3.0 or higher, although with a similar linear relation. The result of this work is the calculation of a calibration parameter for the McGarr model to better predict the magnitudes of seismic events associated with the injected volumes of hydraulic fracturing. This model can be used to predict induced seismicity in future unconventional hydraulic fracturing treatments and prevent large-magnitude seismic events from occurring. The rich dataset available from the WCSB allowed us to carry out a robust analysis of the influence of critical parameters (such as the total injected fluid) in the maximum magnitude of seismic events associated with the hydraulic-fracturing stimulation of unconventional wells. This analysis could be replicated for any other sedimentary basin with unconventional wells by compiling similar stimulation and earthquake data as in this study.

Characteristics of induced seismicity during hydraulic stimulations

2020 ◽  
Author(s):  
Georg Dresen ◽  
Stephan Bentz ◽  
Grzegorz Kwiatek ◽  
Patricia Martínez-Garzón ◽  
Marco Bohnhoff
Keyword(s):  
Real Time ◽  
Seismic Moment ◽  
Induced Seismicity ◽  
Fluid Volume ◽  
Physical Models ◽  
Traffic Light ◽  
Induced Earthquakes ◽  
Induced Earthquake ◽  
Energy Pumping ◽  
Good Agreement

<p>Near-realtime seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1 km deep geothermal well near Helsinki, Finland. The stimulation was monitored in near-real time using a deep seismic borehole array and series of borehole stations. Earthquakes were processed within a few minutes and results informed a Traffic Light System (TLS). Using near-realtime information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied. This procedure avoided the nucleation of a project-stopping red alert at magnitude M2.1 induced earthquake, a limit set by the TLS and local authorities. Our recent studies show that the majority of EGS stimulation campaigns investigated reveal a clear linear relation between injected fluid volume, hydraulic energy and cumulative seismic moments suggesting extended time-spans during which induced seismicity evolution is pressure-controlled. For most projects studied, the observations are in good agreement with existing physical models that predict a relation between injected fluid volume and maximum seismic moment of induced events. Some EGS stimulations however reveal unbound increase in seismic moment suggesting that for these cases evolution of seismicity is mainly controlled by stress field, the size of tectonic faults and fault connectivity. Transition between the two states may occur at any time during injection, or not at all. Monitoring and traffic-light systems used during stimulations need to account for the possibility of unstable rupture propagation from the very beginning of injection by observing the entire seismicity evolution in near-real-time and at high resolution could possibly provide a successful physics-based approach in reducing seismic hazard from stimulation-induced seismicity in geothermal projects.</p>

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