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IEAGHG Monitoring and
Environmental Networks
Combined Meeting. August
2013
Induced seismicity in global injection
projects and implications for CCS
M.Gerstenberger, A. Nicol, C.Bromley,
R.Carne, L.Chardot, S.Ellis, C.Jenkins,
T.Siggins, E. Tenthoray, P.Viskovic
Cooperative Research Centre
for Greenhouse Gas
Technologies (CO2CRC)
© CO2CRC
All rights reserved
What is Induced Seismicity?
From Sminchak and Gupta, 2003
• Earthquakes that, by human activity, have either been:
• Advanced in time on existing faults/fractures
• Caused to occurr on new faults/fractures
• Can be any magnitude, microseismicity (M<2) or greater
• “Microseismicity” and “Induced Seismicity” are not interchangable
What is Induced Seismicity?
From Sminchak and Gupta, 2003
Key Questions
• What magnitudes, rates, timing and locations of induced earthquakes can we expect?
• What don’t we know about induced seismicity and how can these knowledge gaps be closed?
• What are the risks and can these be quantified?
• How do we best reduce and mitigate the risks?
Case Studies and Observations
• Datasets:
– Literature review of existing data
– <10 CO2 injection sites
– ~90 sites injection and extraction of water, gas or
hydrocarbons.
– Earthquake magnitudes M -1 to 7 (mostly < M4.5).
– Many sites have no recorded seismic events.
• Purpose:
• Document current understanding.
• Identify knowledge gaps.
• Recommend future work.
• Decrease risks and improve their management
Locations of Injection Sites
The biggest obstacle in understanding
Induced Seismicity: Lack of Data!
• Data catalogue is small and quality of seismograph networks
variable. Particularly for CO2
• Available data biased toward sites where induced seismicity rates
and earthquake maximum magnitudes are high.
• Statistical modelling is possible but is conservative (overly?)
• Physics based modelling is happening, but lacks validation against
observations and fundamentals are not yet understood (wider
seismological community)
-2
-1
0
1
2
3
4
5
6
7
8
1940 1950 1960 1970 1980 1990 2000 2010 2020
Eve
nt
Mag
nit
ud
e
Years
Induced Seismicity Dataset
Otway(Aust)
Weyburn(Can)
Maximum Magnitude
N=91
Induced Seismicity and CO2 Storage
• Induced seismicity for CO2 storage sites low in numbers
(<100/yr) and magntiudes (M-3 to 1).
• Little or no induced seismicity reported for several CCS
sites (e.g., Sleipner, In Salah, Ketzin, Cranfield, Frio,
Nagoaka)
• Low numbers of events partly due to limitations of
seismograph networks, small number of sites and generally
low rates of injection.
• Questions remain about whether commerical-scale
injection projects will induce comparable rates and
magnitudes of seismicity.
Magnitudes and Size Populations
Baisch et al. (2006 & 2009)
Basel, Switzerland
Magnitude completeness
~ML 1.1-1.2
b-value 0.83
Cooper Basin, Australia
Magnitude completeness
~ML -0.6
Slip (S)
S ~6-90 cm
Size ~8-40 km
S ~0.6-9 cm
Size ~0.8-4 km
S ~0.6-9 mm
Size ~80-400 m
S ~0.06-0.9 mm
Size ~8-40 m
S ~0.006-0.09 mm
Size ~0.8-4 m
Modified from Zoback & Gorelick (2012)
Deichmann & Giardini (2009)
Event Locations
Majer et al. (2007)
Soultz-sous-Forêts, France
Timing of Events
30% of events post injection
Factors influencing induced seismicity
(Shapiro et al., 2007)
Some key factors
• Pressure and pressure change,
• Change in temperature and chemistry,
• Injected volume and plume dimensions,
• Injection rates and rock permeabilities,
• Rock strength,
• Locations and numbers pre-existing
faults,
(Healy et al., 1968)
Summary of Observations
• Very few induced earthqukes recorded/published for CO2
storage sites.
• Most events M<4.5 for fluid injection or extraction sites.
• Rare events of M5-6 and possibly up to M7.
• Damage from these events uncommon but public anxiety
increasingly encountered.
• Reservoir response to fluid injection or extraction highly
variable and not yet predictible.
• Require improved understanding to identify sites and
reservoir conditions where induced seismicity likely, to
develop risk reduction and mitigation measures.
Induced Seismicity Risk Management
• Populations of earthquakes follow a power law frequency magnitude distribution (Gutenberg-Richter law)
• The maximum possible magnitude of any population is not well constrained
• There is always some possibility of a larger magnitude earthquake, even if very small
• Observations support that populations of induced earthquakes behave as populations of natural earthquakes
• Risk: Probability of Occurrence X Consequences
• There is a non-nill risk from induced earthquakes, but it is likely to be small in carefully selected sites (with current understanding)
Induced Seismicity Risk Management
Primary Risks
• Decrease or loss of stakeholder support.
• Reduction of seal integrity.
• Damage to infrastructure and property.
Risk reduction and mitigation tools
• Public engagement and education.
• Reservoir pressure management.
• Real-time microseismic monitoring.
• Establish induced seismicity management
plans and strategies prior to injection.
theaccidentalsuccessfulcio.com
After Bommer et al. (2006)
Traffic Light System for EGS
Knowledge Gaps & Future Work
• Create accessible global database for injection induced
seismicity observations to facilitate model development and
seismicity forecasting.
• Increase understanding of induced earthquake processes by
conducting more systematic and detailed studies.
• Improve reality of physical models to increase their
predictive power.
• Examine how earthquake populations may change with
increasing injected CO2 volumes and plume size.
• Induced seismicity collaboration and knowledge transfer to
the CCS community from other industries and interest
groups.
• Develop CCS specific guidelines for risk management of
induced seismicity.
Impro
ved F
ore
castin
gR
isk
Managem
ent
Conclusions
• Complete monitoring down to small events is key to:
– Better understand the behaviour of induced earthquakes
– Understand the behaviour of a particular reservoir
• Induced Seismicity widely reported over last 40 years
• Few earthquakes at CCS sites, but small volumes and few
sites
• Case histories show data show relations, most notably
between max magnitude and total volume injected/injection
rate.
• Physical and statistical models in relatively early stages of
development. Statistical models better established
• Risks can be reduced and mitigated using systematic and
structured risk management programme
CO2CRC Participants
Supporting Partners: The Global CCS Institute | The University of Queensland | Process Group | Lawrence Berkeley National Laboratory
CANSYD Australia | Government of South Australia | Charles Darwin University | Simon Fraser University