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TRANSCRIPT
Oklahoma Earthquakes and Injection of Produced Water
Jeremy Boak, DirectorOklahoma Geological Survey
February 16, 2016
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The Oklahoma Geological Survey is a state agency for research and publicservice located on the Norman Campus of the University of Oklahoma andaffiliated with the OU College of Earth and Energy. The Survey is charteredin the Oklahoma Constitution and is charged with investigating the state'sland, water, mineral, and energy resources and disseminating the resultsof those investigations to promote the wise use of Oklahoma's naturalresources consistent with sound environmental practices.
We are not a regulatory authority
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OGS Seismic Monitoring Program
● OGS seismic network began operating in 1978
• Location, time, & magnitude calculated by seismologists & trained analysts
• Raw data archived & publicly available at international data management center
• Two-way real-time sharing with USGS
• Data available to Corporation Commission, researchers & general public
● Website (http://www.ou.edu/ogs) provides:
• earthquake catalogs, recent earthquake lists
• maps, research results and educational materials
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M4.2 9/9/14 near Medford
OGS Uses about 50 Stations to Locate Oklahoma Earthquakes
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Measuring an Earthquake● Magnitude is a scaled estimate of energy released as
seismic waves and is proportional to rupture area
● Magnitude measured multiple ways (ML, mb, Mw, Mo, Ms)
● Magnitude estimates rarely the same between different methods
● All magnitude measures are uncertain
● Magnitude scales logarithmic (+1 unit of magnitude = ~10 times shaking & ~32 times the energy release)
● Earthquake Intensity is a qualitative estimate (using Modified Mercalli scale ranging from I-XII)
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Most Earthquakes Occurring in ~16% of the Area of the State
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Alfalfa
Oklahoma
Payne
Woods
Lincoln
Grant
Garfield
Logan
Noble
Pawnee
Earthquakes Occur in the Basement below Oil and Gas Activity
● Average Depth about 5.5 km (~18,000 ft)
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OGS OF1-2015
● Most earthquakes occur within crystalline basement
● Deeper than most oil and gas operations
● Many salt water disposal wells may be in communication with crystalline basement
Earthquakes Occurring on Faults Oriented in Preferred Directions
Active Fault Orientations 2014Natural Stresses and
Earthquakes
OGS OF1-2015
● Earthquakes occur on faults optimally and sub-optimally oriented within Oklahoma’s tectonic stress regime (N85°E)
● Both triggered and naturally occurring earthquakes release accumulated tectonic stress on these faults
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MaximumHorizontalStress
Earthquakes 2009-2015
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Alfalfa
Oklahoma
Payne
Woods
Lincoln
Grant
Garfield
Logan
Noble
Pawnee
Seminole
Okfuskee
Oklahoma M2.8+ Earthquakes
10
0
1
2
3
4
5
6
7
Jan-11 Jan-12 Jan-13 Jan-14 Jan-15 Jan-16 Jan-17
Earth
quak
es p
er D
ay
Earthquakes 2.8+30 Day Average180 Day Average
Earthquake Capital of the U. S.?
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1
10
100
1000
10000
2 3 4 5 6
Cum
ulat
ive
Freq
uenc
y
Magnitude
Oklahoma 2015
Oklahoma 2014
Oklahoma 2011
California 2015
Human Activity Can Induce Earthquakes
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Fluid Pressure increase from
injectionFigure modified from: http://www.earthmagazine.org/article/ground-shaking-research-how-humans-trigger-earthquakes
Underground Injection Control (UIC) Class II Injection Salt Water Disposal (SWD) Wells
Murray 2014, OGS OF5-2015
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Earthquake Activity Occurs Where Deep Injection Increases Substantially
14Source: Walsh, F. R., and Zoback, M. D. (2015) Oklahoma’s recent earthquakes and saltwater disposal. Sci. Adv. 2015; 1:e1500195, 18 June 2015
Areas of Lower SWD Show Lower Earthquake Activity
15Source: Walsh, F. R., and Zoback, M. D. (2015) Oklahoma’s recent earthquakes and saltwater disposal. Sci. Adv. 2015; 1:e1500195, 18 June 2015
SWD Includes Very Little Flowback Waterfrom Hydraulic Fracturing
16Source: Walsh, F. R., and Zoback, M. D. (2015) Oklahoma’s recent earth-quakes and saltwater disposal. Sci. Adv. 2015; 1:e1500195, 18 June 2015
Earthquakes, Oil & Water
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0
20
40
60
80
100
120
140
160
180
200
0
10
20
30
40
50
60
70
80
90
100
2009 2010 2011 2012 2013 2014 2015 2016 2017
Ear
thqu
akes
per
Mon
th
Mon
thly
Vol
ume
(Mil
lion
Bar
rels
)
M2.8+ Earthquakes
12 County Injection
AOI 274 Arbuckle Well Injection
Oklahoma Oil Production
Disposal Rate (MMBWPD) in 274 Arbuckle SWD Wells
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0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Jan-
14
Apr
-14
Jul-1
4
Oct
-14
Jan-
15
Apr
-15
Jul-1
5
Oct
-15
Jan-
16
Dis
posa
l Rat
e (M
M B
PD
)
No OCC Directive
OCC Directive
OCC Reduction
Focus of Seismic Activity Shifting to Northwest
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206221
115
275
187
79
1 4 10
50
100
150
200
250
300
Jan-Jun 2015 Jul-Dec 2015 2016 to Date
Num
ber
of
Ear
thqu
akes
(M
3.0
+)
2015-16 Earthquakes by Region
Northwest (5)
Central (9)
Rest of OK
Summary: Induced Seismicity in Oklahoma
● No documented case of induced seismicity comesclose to the current earthquake rates or the area over which the earthquakes are occurring in Oklahoma
● The OGS considers it very likely that the majority of recent earthquakes, particularly those in central and north-central Oklahoma, are triggered by the injection of produced water in SWD wells.
● Hydraulic fracturing flowback water only contributes a small amount to the SWD apparently responsible for the observed rate of earthquakes
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Acknowledgments● OGS Staff Engaged on the Seismicity Issue
● Publications & Outreach: Ted Satterfield, Jennifer Morris
● Seismology: Jefferson Chang, Fernando Ferrer, NoorulannGhouse, Jordan Williams, Isaac Woelfel
● Hydrogeology, Geology, Geophysics: Kyle Murray, Richard Andrews, Kevin Crain, Steve Holloway
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● OGS website : http://www.ou.edu/ogs
• Report Feeling an Earthquake
ü Quicklink on homepage
• Earthquake FAQ
• Recent Earthquakes
• Current Publications
● Earthquake Preparedness
● http://www.earthquakes.ok.gov
● http//:www.ok.goc/reddirtready/
● http://www.ready.gov/earthquakes
● http://www.dropcoverholdon.org/
● http://www.earthquakecountry.info/roots/index.php
@OKearthquakes
Oklahoma Geological Survey –Earthquake Notices
okgeosurvey
Oklahoma Geological Survey
OKgeosurvey
ogs.ou.edu
Questions or Comments?