Subsurface Stress and Induced Seismicity Pillar DOE SubTER Briefing Nov 17, 2015 Multi-Lab Working Group: Co-Leads: Tom Daley (LBNL) & Grant Bromhal (NETL) Dave Coblentz (LANL), Moo Lee (SNL), Josh White (LLNL), Bill Foxall (LBNL), additional contribution from C. Strickland (PNNL)

Subsurface Stress and Induced Seismicity: Motivation 1. Induced seismicity is now a major national issue affecting nearly all subsurface activities. 2. Subsurface stress state is a true ‘Grand Challenge’ impacting our ability to engineer the subsurface. Central US Seismicity Associated with Fluid Injection, From Weingarten, 2015.

A real and permanent characterization and control of the subsurface state of stress should become the new paradigm in order to optimize fracturing processes and ensure efficient and environmentally safe engineered fluid pathways.

Motivation: Inability to monitor/manipulate subsurface stress inhibits our control of the subsurface for energy production and waste storage JASON Report (2014) stated ‘…that the U.S. DOE take a leadership role in the science and technology for improved measurement, characterization, and understanding of the state of stress of engineered subsurface systems in order to address major energy and security challenges of the nation.’

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Stress is a complex 3D quantity very difficult to measure Measured in-situ via ‘proxies’: e.g. Strain, seismic velocity, induced fractures, etc

Well bore breakouts and induced fractures give us our best subsurface information. However – this is a very localized measurement, and impacted by drilling (‘stress cage’)

Motivation: Current Understanding and Controls Are Not Adequate: Stopping Injection Does Not Immediately Stop Seismicity

Example Injection Induced Earthquakes: 1964 Rangely, Co. M3.4 1967 Rocky Mntn Arsenal., Co. M4.9 2000 Paradox Valley, Co. M4.3 2011 Guy, Ark. M4.7 2011 Youngstown, Oh. M3.9 2011 Raton Basin, Co/NM M5.3 2011 Prague, Ok M5.6 Rubinstein and Alireza, 2015

Seismicity and injection flow rate: Basel geothermal project. Canceled due to public concern over seismicity. From Bachmann, et al., 2011.

Measuring and Manipulating Stress/IS: State-of-the-Art Subsurface Stress – Magnitude and Orientation Borehole: •Mini-fracs; leak off tests; image logs (breakouts); s-wave splitting; over coring Field to Regional: •Seismicity moment tensor / focal mechanism solutions; not absolute magnitudes, only ratios •Surface deformation (tilt/InSAR/GPS): invert for fracture orientation; •In-situ (tunnel, mines): flat jack; strain gauge  Issues:  3D velocity structure, material properties, fault/fracture properties – all have large uncertainty; assume static and homogeneous local properties; even borehole has perturbed stress field  Laboratory studies can probe rock properties as function of stress but not in-situ; unclear how to scale to reservoir

Significant related activities • World Stress Map Project – database of global intraplate stress indicators (from focal mechanisms, borehole data, and geologic structures). • USGS • Many academic and govt. groups study stress and induced seismicity monitoring and analysis –

Induced Seismicity – Location and Magnitude Measurement technology is fairly advanced  Issues:  Signal to noise is cost limited ; e.g. # sensors, sensor location  State of stress uncertain  uncertain velocity models,  fault location/properties

Risk Assessment  I.S. Traffic light systems; ad-hoc; need rigorous methods Hazard assessments: mainly developed for natural seismicity

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E.g. recent Oklahoma and Kansas induced seismicity monitoring and analysis programs

A wealth of knowledge from earthquake seismology

Pillar Elements and Objective 10 Year Objective

Subsurface Stress & Induced Seismicity Measurement and manipulation of stress beyond the borehole

Measurement and manipulation of induced seismicity

Relate stress manipulation and induced seismicity to permeability

Applied risk analysis to assess impact of subsurface manipulation

Improve measurement and manipulation of subsurface stress, along with improved control of induced seismicity, as necessary for adaptive control of subsurface fluids and processes.

Develop a common set of observations and analyses that can be used to assess both incremental development of current tools and application of novel concepts. Achieve metrics for Stress and I.S. Field Observatories

Elements: 10 Year Goals Measurement and manipulation of stress beyond the borehole

 Achieve measurement precision and spatial resolution of stress magnitude and orientation necessary for adaptive control of subsurface processes, as defined by metrics.

Measurement and manipulation of induced seismicity

 Locate and characterize critically stressed faults before injection and before seismicity of concern occurs, meeting the metrics defined.

Relate stress manipulation and induced seismicity to permeability

Applied risk analysis to assess impact of subsurface manipulation

 Develop utilization of stress and IS to control and characterize flow paths along reactivated faults and fractures, predicting permeability behavior with an order of magnitude improvement over current capabilities.  Develop total system performance assessment tools for SubTER activities. Develop risk-driven adaptive methods to characterize and mitigate seismic risk in near real-time.

Stress Element Metrics

Induced Seismicity Element Metrics

*Benchmark metrics defined during the first two years

Example Element Goals and Activities: Induced Seismicity 2 Year Goal • Acquire representative datasets and evaluate the capability of different monitoring and analysis techniques to detect faults capable of producing ~M4.5 earthquakes. 5 year Goal: • Deploy optimal seismic monitoring technologies and develop analysis methods to achieve the five-year goal metrics of M4 capable faults. Induced Seismicity at The Geysers Geothermal Field (Calpine)

Induced Seismicity at IBDP CO2 injection (Kaven, et al, 2014)

Integration of DOE/USGS instrumentation leads to state-ofart detection at IBDP

Example Activity Induced Seismicity: 2016-2018 Activity 1. Development of a field observatory for detection of faults and development of seismicity monitoring technology: E.g.: Geothermal Site (crystalline or altered lithology); Sequestration Site (Sedimentary lithology): Deploy state-of-art; test new technology; integrate field, lab, theory/models with site focus

Geysers Geothermal Field Seismicity 7 days in 2015: Yellow Recording Stations: Blue

O&G or CO2 Storage: Fault imaging

Activity 2 : Innovative use of passive and active seismic data Utilizing data recorded at SubTER field observatories or other dedicated field site

• Evaluate the precision of earthquake locations and moment tensors achieved using different technologies and analysis methods • Establish comparative benchmarks. Subtasks: 2.1 Novel analysis for 4D imaging and monitoring Ambient Noise Correlation (ANC) and Coda Wave Interferometry (CWI), Virtual Seismometer Method (VSM),

2.2 Full waveform inversion for enhanced characterization of induced seismicity Couple earthquake source estimation and event location within a three-dimensional full elastic waveform modeling and imaging framework.

M1.2 IBDP Hickman, et. al., 2014

Two Example Links to Seedling Projects Fracture and Stimulation in a Deep Mine (kISMET*) • •

Control of subsurface fluid flow: engineering of subsurface permeability Create and design fractures of desired size, aperture, orientation, and connectivity. • Develop an underground facility testing hydraulic stimulation and induced seismicity as controlled by stress, rock properties, and existing fractures. • Stress measurements and modeling of the stress state in crystalline/metamorphic rock – Univ. Wisconsin, Stanford, Golder Associates • Active/passive seismic and electrical monitoring *kISMET = Permeability and Induced Seismicity Management for Energy Technologies ; The Sanford Underground Research Facility (SURF) in South Dakota

Evaluating the State of Stress Away from the Borehole •

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Determining the bulk stress state; characterizing in situ stress from reservoir to regional scales – critical stress state. Characterize the relationship between rock fabric. stress and the evolution of fractures (link kISMET/SURF seedling). Evaluate the sources of the stress field (Regional to local) Reservoir-Scale Stress: Jointly invert displacement (GPS/tilt meter) and velocity (seismic) for the 3D stress field. Seismic waveform coherence and time reversal to evaluate the critical stress state. Critical stress behavior through lab studies and theory.

Pillar Related Activities & Outreach •

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Workshop Proposal: Scientific Exploration of Induced SeisMicity and Stress (SEISMS) – Heather Savage, Lamont-Doherty Earth Observatory – James Kirkpatrick, McGill University – James Mori, Kyoto University – Emily Brodsky, UC Santa Cruz – William Ellsworth, USGS/Stanford – Tom Daley, LBNL AGU SubTER Poster Session Society of Exploration Geophysicists (SEG) – Research Committee presentation Oct 2015

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Planned review/collaboration with USGS Director of Earthquake Science Center (Steve Hickman)

Seeding description in American Association of Rock Mechanics

Summary • Induced seismicity is a national concern and can limit subsurface engineering for energy purposes. • Subsurface stress state is a key issue for fracture/fluid manipulation, induced seismicity and is a true scientific grand challenge. • We need to understand and control risk while manipulating the stress state for adaptive control of fractures and permeability.