Oklahoma Earthquakes:Evolving Patterns, Likely Causes, State

Actions, Industry Engagement

Jeremy Boak, Oklahoma Geological Surveyjboak@ou.edu

June 26, 2017

Energy Information Administration Energy Conference

Washington DC

The Oklahoma Geological Survey is a state agency for research and public service located on theNorman Campus of the University of Oklahoma and affiliated with the OU College of Earth andEnergy. The Survey is chartered in the Oklahoma Constitution and is charged with investigatingthe state's land, water, mineral, and energy resources and disseminating the results of thoseinvestigations to promote the wise use of Oklahoma's natural resources consistent with soundenvironmental practices.

We are not a regulatory authority

OGS Monitors ~140 Seismometer Stations3

Oklahoma M2.5+ earthquakes4

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2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Inje

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M2.

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M2.5+ EarthquakesArbuckle Injection30 Day Average90 Day Average

Oklahoma earthquakes, 20165

Earthquake map available at OGS website:http://uok.maps.arcgis.com/apps/Minimalist/index.html?appid=3ebaf2b8de02406b94804cbdb5afbec8

M5.12/13/16

M5.89/3/16

M5.011/6/16

Galena Township Fault

Nemaha Fault

Wilzetta Fault

OCC Area of Interest

Measuring an earthquakeMagnitude

Scaled estimate of energy released as seismic waves

Proportional to rupture area

Magnitude measured multiple ways (ML, mb, Mw, Mo, Ms)

Estimates are uncertain, and rarely the same between different methods

Scales logarithmic (+1 unit of magnitude = ~10 times shaking & ~32 times the energy release)

Earthquake Intensity

Varies with distance from the earthquake

Qualitative estimate (using Modified Mercalli scale ranging from I-XII)

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Earthquake magnitude & frequency7

100,000

150

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Krakatoa eruption

Hiroshima atomic bomb

Large lightning boltOklahoma city bombing

Moderate lightning bolt

Chile (1960)Alaska (1964)

Sumatra (2004)Chile (2010)

New Madrid (1812)San Francisco (1906)Charleston SC (1886)

Haiti (2010)

Northridge (1994)

Long Island (1884)

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Magnitude Earthquakes Energy Equivalents

Largest recorded earthquakesVast destructionMassive loss of life

Great earthquakeSevere impactLarge loss of life

Strong earthquakeDamage in $BillionsSome loss of life

Moderate earthquakeProperty damage

Light earthquakeSome property damage

Minor earthquakeFelt by humans

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8

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5

4

3

2

1

10,000

1,500Average tornado

Loma Prieta (1989)

Mount St Helens eruption

Magnitude 2.0 and below = typical micro-seismic events

<1

World’s largest nuclear test (USSR)

Injection induced earthquakes Typical <3.5 (Highest recorded = 5.6)

Ric

hter

Sca

le (l

ogar

ithm

ic)

Frequency of OccurrenceAvg. per year (est.)

Average Tornado

Large Lightning Bolt

Human activity can induce earthquakes

Figure modified from: http://www.earthmagazine.org/article/ground-shaking-research-how-humans-trigger-earthquakes

Fluid Pressure increase from

injection

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Earthquakes occur in basement, on optimally aligned faults

MaximumHorizontalStress

OGS OF1-2015

Active Fault Orientations 2014

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Num

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Depth (km)

2016 Earthquakes

Average 5.8 ± 1.8

Earthquakes occur in areas of large volume disposal wellsMurray 2015, OGS OF5-2015

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Disposal contains <5% flowback water from hydraulic fracturingSource: Walsh, F. R., and Zoback, M. D. (2015) Oklahoma’s recent earth-quakes and saltwater disposal. Sci. Adv. 2015; 1:e1500195, 18 June 2015

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Different plays; different water cuts; different seismic history

Figure Courtesy of Anna Stafford, IPA LLC

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Initial Water Production

Cumulative Injection

Mississippian Limestone Play

HuntonLimestone Play

Nemaha Uplift

State actions on induced seismicity

• Governor creates Coordinating Council on Seismicity (2014)

• OCC directives reduce injection (2015)

• Oklahoma Geological Survey (OGS) position paper (2015)

• Secretary of Energy funds $200,000 seismicity projects (2015)

• Governor’s Water for 2060 Produced Water Working Group (2015)

• RPSEA funded stations added to OGS network (2016)

• Governor’s Emergency Fund $1,387,000 to OCC, OGS (2016)

• New tracking system for earthquakes and injection for OCC (2016)

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Oklahoma Corporation Commission (OCC) Actions14• Arbuckle Group injection

wells in Area of Interest (AOI) submit weekly report of daily injection rate

• Wells in Precambrian basement plugged back or cut injection 50%

• Reductions and shut-in wells reduced overall injection by >900,000 BWPD since mid-2015

• Caps on injection rate in Western and Eastern AOI reduce potential for price-driven increases

Galena Township Fault

Nemaha Fault

Wilzetta Fault

OCC Western Area of Interest

OCC Eastern Area of Interest

Oil Price, Injection Rate and OCC Directed Reductions15

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2011 2012 2013 2014 2015 2016 2017

AO

I AR

buck

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ispo

sal (

Mill

ion

Bar

rels

per

Day

) AOI Arbuckle InjectionOCC ReductionsWTI Oil Price

Recommendations of Produced Water Task Force (2017)1. Reduce challenges to water re-use through targeted regulations and legislation:

• Remove legal ambiguity about ownership of produced water

• Establish bonding requirements for water impoundments without being an impediment

• Make right-of-way for pipelines for recycled/re-used water easier to obtain

• Request delegation from the U.S. EPA to Oklahoma for discharge permits

2. Facilitate re-use of produced water in oil and gas operations

3. Study feasibility of transferring Mississippi Lime produced water to STACK play.

4. Continue evaluation of evaporation as an alternative to injection.

5. Consider all environmental and stakeholder impacts, and data gaps beforeimplementing long-term projects.

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Earthquakes associated with hydraulic fracturing17

STACK & SCOOP Play Areas18

OCC well completion guidance on seismicity

• Action following anomalous seismic activity ≤2 km from completion operations

• Stoplight system, if Oklahoma Geological Survey reports magnitude ≥2.5; ≥3.0M; ≥3.5M earthquake

• Escalating review of operator’s internal mitigation procedures by Oil & Gas Conservation Division of Oklahoma Corporation Commission

• Operations may resume if seismicity stops and mitigation approach considered adequate

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Recent example: Response to earthquakes induced by hydraulic fracturing20

Map View

Hypocenter Depth

50% of Planned Volume

Early Shutdown

Skipped Stages

100 % of Planned Volume

OGS-Industry collaboration on pressure monitoring21

Continuous measurement of hydrostatic head in 14 shut-in UIC Class II (salt water disposal) wells completed in the Arbuckle Group provides insight into induced seismicity

Mewbourne College staff engaged on seismicity issue

• Oklahoma Geological Survey

• Seismology: Jacob Walter, Jefferson Chang, Fernando Ferrer, Andrew Thiel, Isaac Woelfel

• Hydrogeology, Geology, Geophysics: Kyle Murray, Ella Walker, Jordan Williams, Kevin Crain, Steve Holloway,

• Publications & Outreach: Ted Satterfield

• Conoco-Phillips School of Geology and Geophysics

• Seismology: Xiaowei Chen, Nori Nakata

• Geology: Douglas Elmore, Matthew Pranter,

• Geophysics: Kurt Marfurt

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Major additional funding sources

• Research Partnership to Secure Energy for America (RPSEA)

• U. S. Department of Energy

• Oklahoma Secretary of Energy and Environment (through Recovery Act)

• Oklahoma Governor’s Emergency Fund

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Backup Material

Location of OK earthquakes and known faults

0%

20%

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60%

80%

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Frac

tion

of E

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Distance from Fault

Optimal

Suboptimal

Any

• 80% of earthquakes within 5 km of a known fault

• But only 34% of earthquakes within 2 km of any known fault

• 36% of earthquakes within 5 km of an optimally oriented fault

• 12% of earthquakes are within 2 km of an optimally oriented fault

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Earthquakes, Oil and Water26

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) M3.0+ EarthquakesOklahoma Oil Production X10AOI Arbuckle Injection

Earthquake Comparison | Year-to-Year 27

361

1991

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2172

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USGS One-Year Hazard Forecast28

2016 2017

Summary: Induced Seismicity in Oklahoma• No documented case of induced seismicity close to Oklahoma in earthquake rate or affected area

• Only 34% of earthquakes occur within 2 km of any known fault.

• It is not clear the density of faulting is greater in Oklahoma than elsewhere in the mid-continent

• Majority of recent earthquakes in central and north-central Oklahoma likely triggered by injection of produced water in SWD wells

• Hydraulic fracturing flowback water <5% of SWD volume in Arbuckle

• Drop in earthquake frequency since mid-2015 likely results from decreases in injection in Area of Interest driven by oil price and Corporation Commission directives

• Small number of lower magnitude earthquakes apparently associated with hydraulic fracturing manageable through a stoplight system

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Recent Example: Action in Response to Earthquakes Induced by Hydraulic Fracturing30

50% of Planned Volume

Early Shutdown

Skipped Stages

100 % of Planned Volume

Day 3 Day 4 Day 5

3.0

2.0

1.0

Mag

nitu

de

Well 2

Well 1

~$3.5 million total cost

OGS vision: A comprehensive high-quality seismic network 31

Oklahoma M3.0+ earthquakes32

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2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

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M3.

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M3.0+ EarthquakesArbuckle Injection30 Day Average90 Day Average

OCC Directives on Injection33

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2014 2015 2016 2017

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Daily Equivalent MagnitudeEvent DirectivesRegional Directives