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.

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.

Ground-Motion Analysis of Hydraulic-Fracturing Induced Seismicity at Close Epicentral Distance

2019 ◽  
Vol 110 (1) ◽  
pp. 331-344
Author(s):  
Germán Rodríguez-Pradilla ◽  
David W. Eaton
Keyword(s):  
Hydraulic Fracturing ◽  
Ground Motion ◽  
Induced Seismicity ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Strong Motion ◽  
Seismic Velocities ◽  
Traffic Light ◽  
Data Set ◽  
Near Surface

ABSTRACT The application of seismic hazard analysis methods developed for natural earthquakes can provide an effective framework for managing risks of induced seismicity (IS) sequences, particularly for assessment of potential risk to nearby infrastructure. Among various factors, the reliability of these methods depends on the accuracy of the ground-motion prediction equation (GMPE)—especially at close epicentral distances where ground motions are expected to be highest. In addition, potential impacts on local infrastructure can be assessed based on ground-motion-derived intensity values, which provide a basis for some traffic-light protocols that are used for managing fluid IS. GMPEs in many areas of the world, however, are poorly calibrated at close epicentral distances, because the availability of near-source seismograph stations is generally very sparse. This study investigates ground motions generated by an IS sequence, up to local magnitude (ML) 3.77 that occurred during a hydraulic-fracturing stimulation in the Duvernay shale play in central Alberta, western Canada. The sequence was monitored using a near-surface array that was located directly above the hydraulically fractured horizontal wells, providing accurate ground-motion measurements at hypocentral distances <10  km. The local array consisted of a combination of geophones cemented in shallow wellbores to depth of ∼27  m, shallow buried broadband seismometers, and a strong-motion accelerometer. This configuration enabled direct measurement of near-surface seismic velocities in the top 27 m, which provided robust VS30 data used to correct observed ground motions for local site-amplification effects. Our data set extends previous analyses in this region by providing new measurements very close to the epicenters of moderate earthquakes and shows that a recently developed GMPE provides accurate near-source ground-motion estimates.

scholarly journals Checking the site categorization criteria and amplification factors of the 2021 draft of Eurocode 8 Part 1–1

2021 ◽  
Author(s):  
Roberto Paolucci ◽  
Mauro Aimar ◽  
Andrea Ciancimino ◽  
Marco Dotti ◽  
Sebastiano Foti ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Shear Wave ◽  
Ground Motion ◽  
Shear Wave Velocity ◽  
Soft Soil ◽  
Site Amplification ◽  
Soil Conditions ◽  
Eurocode 8 ◽  
Site Specific ◽  
Amplification Factors

AbstractIn this paper the site categorization criteria and the corresponding site amplification factors proposed in the 2021 draft of Part 1 of Eurocode 8 (2021-draft, CEN/TC250/SC8 Working Draft N1017) are first introduced and compared with the current version of Eurocode 8, as well as with site amplification factors from recent empirical ground motion prediction equations. Afterwards, these values are checked by two approaches. First, a wide dataset of strong motion records is built, where recording stations are classified according to 2021-draft, and the spectral amplifications are empirically estimated computing the site-to-site residuals from regional and global ground motion models for reference rock conditions. Second, a comprehensive parametric numerical study of one-dimensional (1D) site amplification is carried out, based on randomly generated shear-wave velocity profiles, classified according to the new criteria. A reasonably good agreement is found by both approaches. The most relevant discrepancies occur for the shallow soft soil conditions (soil category E) that, owing to the complex interaction of shear wave velocity, soil deposit thickness and frequency range of the excitation, show the largest scatter both in terms of records and of 1D numerical simulations. Furthermore, 1D numerical simulations for soft soil conditions tend to provide lower site amplification factors than 2021-draft, as well as lower than the corresponding site-to-site residuals from records, because of higher impact of non-linear (NL) site effects in the simulations. A site-specific study on NL effects at three KiK-net stations with a significantly large amount of high-intensity recorded ground motions gives support to the 2021-draft NL reduction factors, although the very limited number of recording stations allowing such analysis prevents deriving more general implications. In the presence of such controversial arguments, it is reasonable that a standard should adopt a prudent solution, with a limited reduction of the site amplification factors to account for NL soil response, while leaving the possibility to carry out site-specific estimations of such factors when sufficient information is available to model the ground strain dependency of local soil properties.

scholarly journals Did the NSA and GCHQ Diminish Our Privacy? What the Control Account Should Say

2020 ◽  
Vol 7 (1) ◽  
pp. 29-48 ◽  
Author(s):  
Leonhard Menges
Keyword(s):  
Mobile Phone ◽  
Personal Information ◽  
Real Life ◽  
Mobile Phone Data ◽  
Standard Account ◽  
Do So

AbstractA standard account of privacy says that it is essentially a kind of control over personal information. Many privacy scholars have argued against this claim by relying on so-called threatened loss cases. In these cases, personal information about an agent is easily available to another person, but not accessed. Critics contend that control accounts have the implausible implication that the privacy of the relevant agent is diminished in threatened loss cases. Recently, threatened loss cases have become important because Edward Snowden’s revelation of how the NSA and GCHQ collected Internet and mobile phone data presents us with a gigantic, real-life threatened loss case. In this paper, I will defend the control account of privacy against the argument that is based on threatened loss cases. I will do so by developing a new version of the control account that implies that the agents’ privacy is not diminished in threatened loss cases.

scholarly journals AB0612 THE FRACTURE PREVENTION UNIT OF THE VIRGEN MACARENA HOSPITAL REDUCES THE GAP IN THE MANAGEMENT OF OP, PARTICULARLY IN MALES AND MEETS IOF/ESCEO QUALITY STANDARDS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1341.2-1341
Author(s):  
B. Hernández-Cruz ◽  
F. J. Olmo Montes ◽  
M. J. Miranda García ◽  
M. D. Jimenez Moreno ◽  
M. A. Vázquez Gómez ◽  
...  
Keyword(s):  
Fragility Fracture ◽  
Red Light ◽  
Green Light ◽  
Quality Standards ◽  
Type A ◽  
Traffic Light ◽  
Patient Identification ◽  
Reference Time ◽  
Fracture Liaison

Background:The Virgen Macarena University Hospital belongs to the Public Health System of Andalusia and serves 481,296 inhabitants in Seville, Spain. In 2018 the Fracture Liaison Service switched to a multidisciplinary unit.Objectives:To describe FLS, to know the characteristics of patients with emphasis on gender differences and to know the completion of International Osteoporosis Foundation quality standards.Methods:Prospective, observational, analytical, research of usual clinical practice. All the consecutive patients attended from May 2018 to October 2019, ≥50 years, with a fragility fracture (occurred in the previous 24 months) were included. The study was approved by the Ethics Committee, Code 1084-N-16.Results:Our FLS is a type A multidisciplinary Unit, with a high level of intervention in the evaluation, estimation of fracture risk and fall risk, treatment prescription and follow-up of the patients. We included 408 patients, 80% females, one third with ≥80 years. Fragility fractures recorded in 328 women were hip (132, 40%), clinical vertebral (81, 25%) and no hip no vertebral (115, 35%). Those recorded in 82 males were hip (53, 66%), clinical vertebral (20, 24%) and no hip no vertebral (9, 10%), p=0.0001. Males had a higher rate of secondary causes of OP, drinker, and smoking. The most relevant gender difference was the low percentage of patients receiving pre-FF OP treatment. Forty-nine (16%) women versus 9 (7%) males had received it at some point in their life, p=0.04. Two hundred and seventy-one (86%) women vs 48 males (63%) had received it at after their FF in their reference unit, and all them were treated after the FLS evaluation. The probability of a male not receiving prior treatment was 2.5 (95% CI 1.01- 6.51); p=0,04. This probability was 0.64 (0.38-1.09) after the FF. After twelve months of follow-up in FLs, 96% continued treatment, with no differences between men and women. The completion of IOF quality standards was bad (red light) for patient identification items and FLS reference time. It was poor (amber traffic light) for initial OP screening standard and was good (green light) for the remaining 10 indicators. The completion of IOF quality standards was bad (red light) for patient identification items and FLS reference time. It was poor (amber traffic light) for initial OP screening standard and was good (green light) for the remaining 10 indicators (Figure 1).Figure 1.Figure 1.Conclusion:The FLS is a multidisciplinary type A. Its operation has narrowed the gap in diagnosis, treatment, and follow-up of FF patients, especially males. It is essential to improve patient recruitment, reduce referral times and increase the overall assessment of the patients.References:[1]Ganda K. et al. Models of care for the secondary prevention of osteoporotic fractures: a systematic review and meta-analysis, Osteoporos Int 2013;24:293-406.[2]Javaid MK et al. A patient-level key performance indicator set to measure the effectiveness of fracture liaison services and guide quality improvement: a position paper of the IOF Capture the Fracture Working Group, National Osteoporosis Foundation and Fragility Fracture Network. Osteoporos Int. 2020 Jul;31(7):1193-1204.Acknowledgements:Spanish Society of Research in Mineral and Bone Metabolism for its support through the competitive project FLS Excellence 2018 to obtain a training grant from the case management nurse.Disclosure of Interests:Blanca Hernández-Cruz Speakers bureau: Sociedad Española de Reumatología, Abbvie, Roche, Bristol, MSD, Lilly, Pfizer, Amgen, Sanofi, Consultant of: Abbvie, Lilly, Sanofi, STADA, UCB, Amgen, Galapagos., Grant/research support from: Fundación para la Investigación Sevilla, Junta de AndalucíaFundación Andaluza de Reumatología, Sociuedad Española de Reumatología., Francisco Jesús Olmo Montes: None declared., Maria José Miranda García: None declared., María Dolores Jimenez Moreno: None declared., María Angeles Vázquez Gómez: None declared., Mercedes Giner García: None declared., Miguel Angel Colmenero Camacho: None declared., José Javier Pérez Venegas: None declared., María José Montoya García: None declared.

Framework for a Ground-Motion Model for Induced Seismic Hazard and Risk Analysis in the Groningen Gas Field, The Netherlands

2017 ◽  
Vol 33 (2) ◽  
pp. 481-498 ◽  
Author(s):  
Julian J. Bommer ◽  
Peter J. Stafford ◽  
Benjamin Edwards ◽  
Bernard Dost ◽  
Ewoud van Dedem ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Quantitative Estimation ◽  
Epistemic Uncertainty ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Small Magnitude ◽  
Ground Motion Model ◽  
Hazard And Risk ◽  
Groningen Gas Field

The potential for building damage and personal injury due to induced earthquakes in the Groningen gas field is being modeled in order to inform risk management decisions. To facilitate the quantitative estimation of the induced seismic hazard and risk, a ground motion prediction model has been developed for response spectral accelerations and duration due to these earthquakes that originate within the reservoir at 3 km depth. The model is consistent with the motions recorded from small-magnitude events and captures the epistemic uncertainty associated with extrapolation to larger magnitudes. In order to reflect the conditions in the field, the model first predicts accelerations at a rock horizon some 800 m below the surface and then convolves these motions with frequency-dependent nonlinear amplification factors assigned to zones across the study area. The variability of the ground motions is modeled in all of its constituent parts at the rock and surface levels.

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