2010 in Trol
23
Workshop on induced seismicity: Research and technology needs Feb 4, 2010 Stanford University Bechtel Conference Center
description
induced seismicity
Transcript of 2010 in Trol
Workshop on induced seismicity: Research and technology needs
Feb 4, 2010Stanford University
Bechtel Conference Center
Introductory Outline
Motivation, purpose, objectives and goals (why are we here and what do we want to achieve)Summary of past workshops on EGS ISCurrent status of DOE IS activitiesStructure of workshop
Motivation to study Induced seismicity
The success of critical energy technologies will depend on te ability to successfully inject/withdraw fluids in high volumes in the subsurface− EGS− CO2 Sequestration− Natural gas recovery/EOR
High-profile press coverage has focused attention on induced seismicity related to energy projects in the U.S. and Europe− The Geysers, CA; Basel, Switzerland; Soultz, France; Landau, Germany− Oil and gas: Texas− Potential CO2 sequestration sites
Public, economic and regulatory concerns could (already has) delay and possibly cancel projects Risk must be assessed properly to assure public: place risk analysis on a solid scientific and technical basisSeismicity can be ( must be) useful as a resource management tool
Objective and purpose of workshop
Identify critical technology and research needs/approaches to advance the understanding of induced seismicity associated with deep well injection and production, such that:
− The risk associated with induced seismicity can be reduced to a level that is acceptable to the public, policy makers, regulators and operators, and
− The seismicity can be utilized/controlled to monitor, manage and optimize the desired fluid behavior in the subsurface in an economic manner.
Address the hypothesis : With proper study and technology development induced seismicity will not only be mitigated but will become a useful tool for reservoir management.
Public/Industry Concerns About Induced Seismicity
What is the largest earthquake expected?Will small earthquakes lead to bigger ones?Can induced seismicity cause bigger earthquakes on distant faults?Even small felt (micro)earthquakes are annoying.Can induced seismicity be controlled?What controls are (will be) in place to mitigate future induced seismicity?What is the plan if a large earthquake occurs?
Obvious technical questions
What is controlling the limit of seismicity (time and space)?Does induced seismicity follow Omori’s law?− What controls the decay of seismicity after injection
Radius of influence (how close to a critically stressed fault can one be?) − If “natural seismicity” is known to occur deep, can one safely inject
shallow?What are the similarities and differences between natural and Induced earthquakes?− Foreshocks, aftershocks, b-values, etc
What controls the decay of seismicity after injection stops?Will risk assessment be based on past seismicity, “physics” or some combination?
Northern California Historical Seismicity (M 3.5 to 5.0) 1900- 2005
The Geysers
The Geysers Seismicity, 1965 to Present (Smith,2006)Geysers Annual Steam Production, Water Injection and Seismicity
1158
26 2612
0
200
400
600
800
1,000
1,200
1,400
1965 1970 1975 1980 1985 1990 1995 2000 2005
Ann
ual N
umbe
r of S
eism
ic E
vent
s
0
50
100
150
200
250
300
350
Stea
m P
rodu
ctio
n an
d W
ater
Inje
ctio
n (b
illio
n lb
s)
Seismic Events of M>=1.5
Earthquake Count M>=3.0
Earthquake M>=4.0
Steam Production
Water Injection
Potential for Intraplate Seismicity Limits Injection Pressures
Brittle Failure in Critically-Stressed Crust Results
From Creep in Lower Crust and Upper Mantle
Regional Seismicity: 1960-presentPerry Nuclear Power Plant
• January 31, 1986
• Mb 5.0 Event
• Pressures in nearby deep injection wells reached 11.2 MPa above ambient
• Pressure increase may have been responsible for triggering the event
Mountaineer Power Plant
•State of stress: Strike-slip frictional equilibrium
•Small pressure increases could result in reactivation
Basin-Scale Pressure Buildup (bar)
Illin
ois
Nor
thin
g(k
m)
500
600
700
800
900
1000
1100
3025201510864210.2
0.5 years
Near-Field
Far-Field
3025201510864210.2
5 years
Illinois Easting (km)
llino
isN
orth
ing
(km
)
800 900 1000 1100 1200 1300
500
600
700
800
900
1000
1100
3025201510864210.2
50 years
Illinois Easting (km)800 900 1000 1100 1200 1300
3025201510864210.2
100 years
Cutoff Pressure: 0.1 bar
Presenter
Presentation Notes
ΔP from different injection sites interact, elevating pressure buildup in the entire core injection area very soon after injection ΔP attenuates after CO2 injection by propagating away from the core injection area and through the brine flow through caprock as well as outside of model domain. Cut-off is 0.01 bar. Pressure buildup is much less than values that could cause geomechanical damage (much less than regulated maximum pressure); 10 to 30 % of hydrostatic.
Zone of influence from potential earthquakes in the US
Summary of DOE Geothermal Process and Approach
Draft LBNL internal whitepaper (2004)
Three international workshops (2005-2006) − Form technical basis for understanding induced seismicity and a strategy
for developing a protocol for designing “induced seismicity friendly” EGS projects
− Gather international group of experts to identify critical issues (technical and non technical) associated with EGS induced seismicity
Products of work shops and activities − Peer reviewed white paper (IEA Report, Majer et al., 2007)
− Protocol for the development of geothermal sites and a good practice guide (IEA Report)
− Establish Website for community and scientific collaboration
− Instrument all DOE EGS projects for monitoring induced seismicity
− Require all DOE EGS projects to follow protocol
− Establish international collaborations (Iceland, Australia, GEISER)
Summary of 2005/6 workshops on EGS Induced SeismicityOver all Goal
−
Provide information to improve the overall understanding of the relation between reservoir manipulation and seismicity.
− Understand characteristics of seismicityMagnitude/energy distribution (space and time) of seismicityIs it possible to mitigate and optimize production and injection activities at the same time?Does the reservoir reach equilibrium?
− How to accurately assess hazard/risk to local communities and facilities)What parameters are critical to controlling/estimating Seismic activity during “production” activities?
−
What is the minimum knowledge we need to determine how injection and production affect seismic activity?
Stress distribution/thermal conditionsGeologic conditions/historyHistorical seismicityReservoir pressure and temperaturesGeochemistryRate/pressure/volume of injectionSpatial and temporal distribution of wells
Presenter
Presentation Notes
Top Figure a): Vertical cross section through Rye Patch model with wave front time snapshots at two time steps. Interaction of waves with fault reveals attenuation of seismic energy and reflection and refraction off fault. Bottom Figure b): Seismogram section of the waves as recorded in the receiver array along the top of the model. The attenuation of the waves by the fault can be seen as a gap in the amplitudes of the first arriving P-wave. The reflected and refracted waves can be seen originating from the location of the fault as indicated by the red line. Fit of Work within Program Structure: Develop state-of-the-art seismic imaging techniques for geothermal resources exploration in EGS Objectives: Investigate how state-of-the-art seismic imaging techniques, developed for hydro-carbon exploration, can be applied to geothermal resources exploration Work Scope: Numerical 2-D finite difference modeling based on real subsurface parameters obtained at Rye Patch over past years Investigate what signatures faults and fracture zones produce in 2-D seismic data Provide suggestions as to how to reinterpret existing 2-D seismic data sets Investigate how time- and financially expensive 3-D seismic surveys can be optimized for pre-defined targets based on 2-D results Work Organization and Performance: Work is performed at LBNL’s Center for Computational Seismology Work is carried out by Roland Gritto and Ernest Majer of LBNL Current and Future Accomplishments: Result obtained thus far indicate intriguing footprints of blind faults and fracture zones even for single receiver lines, suggesting the reinterpretation of previously acquired 2-D seismic data sets to detect these features Results can be used to optimized design of planned 3-D seismic surveys to maximize definition of target properties Currently no future plans due to stop in funding Knowledge Gaps: Although 3-D state-of-the-art seismic imaging has been successfully used in hydro-carbon exploration, the targets and geological settings in EGS are different such that developed approaches cannot be easily converted to geothermal systems Need to better investigate and understand the kinematics and dynamics of seismic wave propagation in geothermal settings using modeling approaches based on real subsurface geothermal models Advantage of Industry Collaboration: Industry collaboration can provide the required physical parameters and geometries of the EGS systems under investigation. Industry can provide outside review to keep research goals close to industry needs
Induced Seismicity and EGS
What measurements and data are needed and for how long?
−
Seismic
Surface versus borehole
Single versus multi-component
Bandwidth and dynamic range ( Remote sensing/tilt to AE?)
Spatial and temporal coverage
−
Reservoir
Pressure, temperature
Stress
Geochemistry
Fluid state
−
Local ground response
−
Geologic
Faults/fracture
Lithology
−
Other
Gravity
EM/Resistivity
Etc
Presenter
Presentation Notes
Top Figure a): Vertical cross section through Rye Patch model with wave front time snapshots at two time steps. Interaction of waves with fault reveals attenuation of seismic energy and reflection and refraction off fault. Bottom Figure b): Seismogram section of the waves as recorded in the receiver array along the top of the model. The attenuation of the waves by the fault can be seen as a gap in the amplitudes of the first arriving P-wave. The reflected and refracted waves can be seen originating from the location of the fault as indicated by the red line. Fit of Work within Program Structure: Develop state-of-the-art seismic imaging techniques for geothermal resources exploration in EGS Objectives: Investigate how state-of-the-art seismic imaging techniques, developed for hydro-carbon exploration, can be applied to geothermal resources exploration Work Scope: Numerical 2-D finite difference modeling based on real subsurface parameters obtained at Rye Patch over past years Investigate what signatures faults and fracture zones produce in 2-D seismic data Provide suggestions as to how to reinterpret existing 2-D seismic data sets Investigate how time- and financially expensive 3-D seismic surveys can be optimized for pre-defined targets based on 2-D results Work Organization and Performance: Work is performed at LBNL’s Center for Computational Seismology Work is carried out by Roland Gritto and Ernest Majer of LBNL Current and Future Accomplishments: Result obtained thus far indicate intriguing footprints of blind faults and fracture zones even for single receiver lines, suggesting the reinterpretation of previously acquired 2-D seismic data sets to detect these features Results can be used to optimized design of planned 3-D seismic surveys to maximize definition of target properties Currently no future plans due to stop in funding Knowledge Gaps: Although 3-D state-of-the-art seismic imaging has been successfully used in hydro-carbon exploration, the targets and geological settings in EGS are different such that developed approaches cannot be easily converted to geothermal systems Need to better investigate and understand the kinematics and dynamics of seismic wave propagation in geothermal settings using modeling approaches based on real subsurface geothermal models Advantage of Industry Collaboration: Industry collaboration can provide the required physical parameters and geometries of the EGS systems under investigation. Industry can provide outside review to keep research goals close to industry needs
Induced Seismicity and EGS
What data and results exist?- What can we learn from other similar situations? - Path forward.
− Existing data setsSeismicityReservoir/geologicProduction Case historiesExperience with communitiesLessons from non-geothermal but similar?
−
Oil and Gas−
Fluid disposal
−
Dam impoundment−
Excavation/Blast
−
Earthquake Hazard Program
− Current and future monitoring
− Etc.
Presenter
Presentation Notes
Top Figure a): Vertical cross section through Rye Patch model with wave front time snapshots at two time steps. Interaction of waves with fault reveals attenuation of seismic energy and reflection and refraction off fault. Bottom Figure b): Seismogram section of the waves as recorded in the receiver array along the top of the model. The attenuation of the waves by the fault can be seen as a gap in the amplitudes of the first arriving P-wave. The reflected and refracted waves can be seen originating from the location of the fault as indicated by the red line. Fit of Work within Program Structure: Develop state-of-the-art seismic imaging techniques for geothermal resources exploration in EGS Objectives: Investigate how state-of-the-art seismic imaging techniques, developed for hydro-carbon exploration, can be applied to geothermal resources exploration Work Scope: Numerical 2-D finite difference modeling based on real subsurface parameters obtained at Rye Patch over past years Investigate what signatures faults and fracture zones produce in 2-D seismic data Provide suggestions as to how to reinterpret existing 2-D seismic data sets Investigate how time- and financially expensive 3-D seismic surveys can be optimized for pre-defined targets based on 2-D results Work Organization and Performance: Work is performed at LBNL’s Center for Computational Seismology Work is carried out by Roland Gritto and Ernest Majer of LBNL Current and Future Accomplishments: Result obtained thus far indicate intriguing footprints of blind faults and fracture zones even for single receiver lines, suggesting the reinterpretation of previously acquired 2-D seismic data sets to detect these features Results can be used to optimized design of planned 3-D seismic surveys to maximize definition of target properties Currently no future plans due to stop in funding Knowledge Gaps: Although 3-D state-of-the-art seismic imaging has been successfully used in hydro-carbon exploration, the targets and geological settings in EGS are different such that developed approaches cannot be easily converted to geothermal systems Need to better investigate and understand the kinematics and dynamics of seismic wave propagation in geothermal settings using modeling approaches based on real subsurface geothermal models Advantage of Industry Collaboration: Industry collaboration can provide the required physical parameters and geometries of the EGS systems under investigation. Industry can provide outside review to keep research goals close to industry needs
Hypothesis for EGS Induced Seismicity
Increased pore pressure (effective stress changes)Thermal stressVolume change (subsidence, inflation)Chemical alteration of slip surfaces Stress diffusionProduction inducedInjection producedEtc.
Gaps in KnowledgeRelationship between the small and large events
Similar mechanisms and patternsThreshold of events/ triggered?Why do large events occur after shut in.
Source parameters of eventsStress drop versus fault sizeIndication of stress heterogeneity?Seismicity on existing versus new faults - fractures
Experiments to shed light on mechanismsVariation of key parameters (injection rate, vol., temp, pressure, etc.)
Differences between Natural and Induced fracture systemsMaximum size, time of events
Can one manipulate seismicity without compromising production?
Does the reservoir reach equilibrium?
Path Forward
Technical Issues− Further understanding of complex interaction
between stress, temperature, rock and fluid properties
− Alternative methods for creating reservoir“nudge and let it grow” versus massive injections
Community Interaction− Supply timely, open, and complete information− Technical based risk analysis
Common ThemesAll applications need understanding of the effects of injecting/production of fluids in the subsurfaceMust be able to safely (minimize seismicity and leakage) while achieving the necessary fluid injection and withdrawal volumes. Therefore our task (and opportunity) is to identify the research needs and technology development that will be necessary to be successful.DOE Geothermal, fossil energy ( oil and gas CO2 seq) Office of Science, NSF, and USGS all have an interest in the product
Structure of workshopDiscussion orientedMorning dedicated to “background” and lessons learned and identifying gaps in research and technology.− Past induced seismicity examples and how/could risk was/be
estimated− Lessons learned from current IS cases
Lunch: Discussion of Public interactions and community Issues – Review of current practices and future needs Afternoon dedicated to identifying research and technology development paths forward− Lab and EQ Source Mechanism Studies− Field and Instrumentation− Theory/Modeling
Summary of discussions and wrap up, next steps and follow- on activities, action Items, other Items
Objective and purpose of workshop
Identify critical technology and research needs/approaches to advance the understanding of induced seismicity associated with deep well injection and production, such that:
− The risk associated with induced seismicity can be reduced to a level that is acceptable to the public, policy makers, regulators and operators, and
− The seismicity can be utilized/controlled to monitor, manage and optimize the desired fluid behavior in the subsurface in an economic manner.
Address the hypothesis : With proper study and technology development induced seismicity will not only be mitigated but will become a useful tool for reservoir management.
