Design and implementation of a traffic light system for deep geothermal well stimulation in Finland

Ader, Thomas; Chendorain, Michael; Free, Matthew; Saarno, Tero; Heikkinen, Pekka; Malin, Péter; Leary, Peter; Kwiatek, Grzegorz; Dresen, Georg; Bluemle, F.; Vuorinen, Tommi

doi:10.1007/s10950-019-09853-y

Cited by 44 publications

(64 citation statements)

References 24 publications

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“…These authors discuss both empirical and stochastic GMPEs as tools for relating the PGV thresholds to magnitude but opt instead for a purely theoretical relationship between seismic moment, corner frequency and particle velocity. Ader et al (2019) discussed the design of a TLS for a deep geothermal project in Helsinki, highlighting some of the challenges in responding to the question of the best hazard indicator for the risk potential of induced seismic events. The design began by defining PGV levels such that green would correspond to motions that are not felt, amber to amplitudes of motion that might be felt but not cause damage, and the red light corresponding to the threshold level of PGV for cosmetic damage.…”

Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

“…The design began by defining PGV levels such that green would correspond to motions that are not felt, amber to amplitudes of motion that might be felt but not cause damage, and the red light corresponding to the threshold level of PGV for cosmetic damage. Ader et al (2019) identified two potential problems with using a PGV criterion for triggering different levels of the TLS. Firstly, false positives may arise due to ground vibrations from other sources, and secondly, false negatives may arise if the highest PGV should occur at a location other than where seismic instruments are installed to monitor the shaking.…”

Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

“…Firstly, false positives may arise due to ground vibrations from other sources, and secondly, false negatives may arise if the highest PGV should occur at a location other than where seismic instruments are installed to monitor the shaking. To address these potential pitfalls, Ader et al (2019) proposed two sets of criteria for triggering of the amber level of the TLS: either the exceedance of the PGV threshold (1 mm/s) at any sensor in association with an event of at least M L 1.0, or an event of M L ≥ 1.2. The red light was triggered simply by an event of M L ≥ 2.1.…”

Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

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

Verdon

Bommer

2020

J Seismol

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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.

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Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

Section: Tlss As Seismic Risk Mitigation Toolsmentioning

confidence: 99%

See 1 more Smart Citation

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

Verdon

Bommer

2020

J Seismol

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“…A MW 2.1 red alert threshold of the TLS defined by the local authorities was successfully avoided by a careful adjustment of the hydraulic energy input in response to real-time monitoring of the spatio-temporal evolution of seismicity. The largest seismic event was confined to a moment 50 magnitude of MW 1.9 (Ader et al, 2019;Kwiatek et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…In this study we present a refined high-resolution dataset of seismicity induced during stimulation of the world's deepest geothermal EGS in the Helsinki suburban area in 2018 (Kwiatek et al, 2019;Ader et al, 2019;80 Hillers et al, 2020). The data was collected using a combined seismic network of individual sensors in shallow boreholes framing the injection site combined with a multi-level vertical geophone array at ≥2 km depth.…”

Section: Introductionmentioning

confidence: 99%

Seismicity during and after stimulation of a 6.1 km deep Enhanced Geothermal System in Helsinki, Finland

Leonhardt¹,

Kwiatek²,

Martínez‐Garzón³

et al. 2020

Preprint

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Abstract. In this study, we present a high-resolution dataset of seismicity framing the stimulation campaign of a 6.1 km deep Enhanced Geothermal System (EGS) in Helsinki suburban area and discuss the complexity of fracture network development. Within St1 Deep Heat project, 18 160 m3 of water was injected over 49 days in summer 2018. The seismicity was monitored by a seismic network of near-surface borehole sensors framing the EGS site in combination with a multi-level geophone array located at ≥ 2 km depth. We expand the original catalog of Kwiatek et al. (2019) and provide the community with the dataset including detected seismic events and earthquakes that occurred two month after the end of injection, totalling to 61 163 events. We relocated events of the catalog with sufficient number of available phase onsets and moment magnitudes between Mw −0.7 and Mw 1.9 using the double-difference technique and a new velocity model derived from a post-stimulation vertical seismic profiling campaign. The analysis of the fault network development at reservoir depth of 4.5–7 km is one primary focus of this study. To achieve this, we investigate 191 focal mechanisms of the induced seismicity using cross-correlation based technique. Our results indicate that seismicity occurred in three spatially separated clusters centered around the injection well. We observe a spatio-temporal migration of the seismicity during the stimulation starting from the injection well in northwest (NW) – southeast (SE) direction and in northeast (NE) direction towards greater depth. The spatial evolution of the cumulative seismic moment, the distribution of events with Mw ≥ 1 and the fault plane orientations of focal mechanisms indicate an active network of at least three NW–SE to NNW-SSE orientated permeable zones which is interpreted to be responsible for migration of seismic activity away from the injection well. Fault plane solutions of the best-constrained focal mechanisms as well as results for the local stress field orientation indicate a reverse faulting regime and suggest that seismic slip occurred on a sub-parallel network of pre-existing weak fractures favorably oriented with the stress field, striking NNW-SEE with a dip of 45° ENE, parallel to the injection well.

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Limited earthquake interaction during a geothermal hydraulic stimulation in Helsinki, Finland

Kwiatek

Martínez‐Garzón

Davidsen

et al. 2022

Preprint

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Geothermal energy is considered an important and growing source of low-carbon-footprint energy. Development of deep Enhanced Geothermal Systems (EGS) using massive fluid injection (hydraulic fracturing) to improve reservoir permeability often leads to the occurrence of induced seismicity (e.g., Majer et al., 2012). Large earthquakes associated with anthropogenic fluid injection activities such as in Basel, Switzerland (e.g., Giardini, 2009)

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Design and implementation of a traffic light system for deep geothermal well stimulation in Finland

Cited by 44 publications

References 24 publications

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

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

Seismicity during and after stimulation of a 6.1 km deep Enhanced Geothermal System in Helsinki, Finland

Limited earthquake interaction during a geothermal hydraulic stimulation in Helsinki, Finland

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