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