## Class II Underground Injection Control Well Data for 2010

– 2013 b y

Geologic Zones of Comple tion, Oklahoma

Open

- File Report (OF1

- 2014)

Kyle E. Murray

Oklahoma Geological Survey

University of Oklahoma

100 East Boyd Street

Norman, OK 73019Oklahoma Geological Survey, Open

- File Report Disclaimer:

Open

- File Reports are used for the dissemination of information that fills a public need and

are intended to make the results of research available at the earliest possible date

. Because of

their nature and possibility of being superseded, an Open

- File Report is intended as a preliminary

report not as a final publication. Analyses presented in this ar ticle are based on information

available to the author, and do not necessarily represent the views of the O klahoma Geological

Survey

, the University of Oklahoma

, their employ ees, or the State of Oklahoma. The accuracy of

the information contained herein ar e not guaranteed and the mention of trade names are not an

endorsement by the author, the O klahoma Geological Survey, or the University of Oklahoma

.

Suggested Citation:

Murray KE (2014) Class II Underground Injection Control Well Data for 2010

– 2013 by

Geologic Zones of Complet ion, Oklahoma

. Oklahoma Geological Survey Open

- File Report

(OF1

- 2014). Norman, OK

. pp. 3 2

.

### Contents

Abstract

................................ ................................ ................................ ................................ ........... 1

1. Introduction

................................ ................................ ................................ ............................. 2

1.1. Undergrou nd Injection Control (UIC) Well Designations

................................ ............... 2

1.2. Potential for Induced Seismicity from Fluid Injection

................................ ..................... 3

1.3. Objectives

................................ ................................ ................................ ......................... 3

2. Methods

................................ ................................ ................................ ................................ ... 3

2.1. Compile UIC W ell Locations and Injection Data

................................ ............................ 3

2.2. Quality Assurance Quality Control (QAQC) of UIC Data

................................ .............. 3

2.3. Attribute Injection Zones for Wells

................................ ................................ ................. 4

2.4. Summarize Volumes by Zone and County

................................ ................................ ...... 4

2.5. Obtain Earthquake Data for 2010

– 2013

................................ ................................ ........... 4

3. Results and Discussion

................................ ................................ ................................ ............ 5

3.1. Highest Volume Class II UIC Wells

................................ ................................ ................ 5

3.2. SWD Wells and Volumes by Geologic Zone of Completion

................................ .......... 5

3.3. EORI Wells and Volumes by Geologic Zones of Completion

................................ ........ 6

3.4. Temporal Trends in SWD by County

................................ ................................ .............. 7

3.5. Injection Depths and Pressures of SWD

................................ ................................ .......... 7

3.6. Temporal Trends in EORI by County

................................ ................................ .............. 8

3.7. Seismic Activity in Oklahoma

................................ ................................ ......................... 9

4. Future Directions

................................ ................................ ................................ ..................... 9

5. References

................................ ................................ ................................ ............................... 9

Abbreviations, U nits, and Definitions

................................ ................................ .......................... 11



### Tables

Table 1 Number of active SWD (i.e., 2D) wells in Oklahoma, by zone of completion

................. 5

Table 2 Volume of water injected into SWD (i.e., 2D) wells in Oklahoma, by zone of completion

................................ ................................ ................................ ................................ ......................... 6

Table 3 Number of active EORI (i.e., 2R) wells in Oklahoma, by zone of completion

................. 6

Table 4 Volume of water injected into EORI (i.e., 2R) wells in Oklahoma, by zone of completion

................................ ................................ ................................ ................................ ......................... 6

Table 5 SWD (i.e., 2D) volumes by county

................................ ................................ .................... 7

Table 6 Median wellhead pressures reported for active SWD (i.e., 2D) wells, by completion zone

................................ ................................ ................................ ................................ ......................... 8

Table 7 EORI (i.e., 2R) volumes by county

................................ ................................ ................... 8

### Figur es

Figure 1 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells

(i.e., 2D) during 2010. Chart of SWD well volumes in 2010 by county.

......................... 12

Figure 2 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells

(i.e., 2D) during 2011. Chart of SWD well volumes in 2011 by county.

......................... 13

Figure 3 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells

(i.e., 2D) during 2012. Chart of SWD well volumes in 201 2 by county.

......................... 14

Figure 4 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells

(i.e., 2D) during 2013. Chart of SWD well volumes in 2 013 by county.

......................... 15

Figure 5 Map of EORI wells and relative volumes of water injected into EORI Class II UIC

wells (i.e., 2R) during 2010. Chart of EORI well volumes in 2010 by county.

............... 16

Figure 6 Map of EORI wells and relative volumes of water injected into EORI Class II UIC

wells (i.e., 2R) during 2011. Chart of EORI well v olumes in 2011 by county.

............... 17

Figure 7 Map of EORI wells and relative volumes of water injected into EORI Class II UIC

wells (i.e., 2R) during 2012. Chart of EORI well volumes in 2012 by county.

............... 18

Figure 8 Map of EORI wells and relative volumes of water injected into EORI Class II UIC

wells (i.e., 2R) during 2013. Chart of EORI well volumes in 2013 by county.

............... 19

Figure 9 Chart of UIC well volumes in 2010 by geologic zone of completion.

........................... 20

Figure 10 Chart of UIC well volumes in 2011 by geologic zone of completion.

......................... 21

Figure 11 Chart of UIC well volum es in 2012 by geologic zone of completion.

......................... 22

Figure 12 Chart of UIC well volumes in 2013 by geologic zone of completion.

......................... 23

Figure 13 Depths, below land surface, for completion intervals of 2010

– 2013 active SWD (i.e.,

2D) wells in Oklahoma

................................ ................................ ................................ ..... 24

Figure 14 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2010

................. 25

Figure 15 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2011

................. 25

Figure 16 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2012

................. 26

Figure 17 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2013

................. 26

Figure 18 M ap of earthquakes and relative magnitudes during 2010, data from OGS earthquake

catalog. Chart of >=3.0 magnitude earthquakes in 2010 by month.

................................ . 27

Figure 19 Map o f earthquakes and relative magnitudes during 2011, data from OGS earthquake

catalog. Chart of >=3.0 magnitude earthquakes in 2011 by month.

................................ . 28

Figure 20 Map of ea rthquakes and relative magnitudes during 2012, data from OGS earthquake

catalog. Chart of >=3.0 magnitude earthquakes in 2012 by month.

................................ . 29

Figure 21 Map of earthq uakes and relative magnitudes during 2013, data from OGS earthquake

catalog. Chart of >=3.0 magnitude earthquakes in 2013 by month.

................................ . 30

Figure 22 Number of earthquakes versus depth of focal point for 2000

– 2013

............................ 31

Figure 23 Spatiotemporal comparison of change in SWD versus change in seismicity at a county

scale

................................ ................................ ................................ ................................ ... 321

Class II Underground Injection Control Well Data for 2010

– 2013 by Geologic Zones of

Comple tion, Oklahoma

Kyle E. Murray

Hydrogeologist

Oklahoma Geological Survey

Norman, OK 73019

e

- mail: kyle.murray@ou.edu

Abstract

Water and energy resources are fundamentally connected and have created what some refer to

as the energ y

- water or water

- energy nexus. A common goal of water and energy management is

to maximize the supply of one while mi nimizing the use of the other. Water management in

Oklahoma has become an important issue not only because of recurring droughts and increa sed

water demand, but because large volumes of saltwater are being co

- produced with oil and gas

and must be properly managed. Oklahoma’s statewide co

- produced water volumes were

estimated to range from 811

– 925 million barrels (MMbbl) from 2000

– 2011. In the last few

years, an estimated 40

– 60% of Oklahoma’s co

- produced water originated from oil and gas wells

in the Mississippian play where median fluid production ratios of H 2 O:oil and H 2 O:gas w ere 7.4

and 9.8, respectively. Other practices, such as dewatering in the Hunton play of central

Oklahoma, have resulted in high volumes of co

- produced water and subs equently high volumes

for saltwater disposal ( SWD ). Seismic activity from 2009

– 2014 far exceeds historic seismicity

and

, in a few cases, has been correlated to subsurface fluid injection in the midcontinent

. Therefore, there is an urgent need to quantify volumes and pressures of injections by geologic

zone of completion, and use this information to develop best management practices for water

that is co

- produc ed with oil and gas.

This report is part of an ongoing effort to compile Oklahoma’s Class II underground injection

control (UIC) well data on county

- and annual

- scales by geologic zone of completion.

Thousands of annual fluid injection reports and well completion reports, filed by operators with

the Oklahoma Corporation Commission (OCC), were the primary sources of data for this report.

Data were compiled into a relati onal database, checked against scanned and electronic OCC

records, and then summar ized at county

- , state

- , and annual

- scales.

Because most previous studies indicate that SWD, especially into basal sedimentary strata, are

in closer proximity to basement faults

, the volumes and pressures of SWD wells we re more

carefully examined than enhanced oil recovery injection (EORI) wells

. Statewide (excluding

Osage County) SWD volumes were 878, 99 1

, 1067, and 1193 MMbbl from 2010

– 2013,

respectively, and are increasing at a rate that mimics statewide petroleum production. SWD

volumes into the Arbuckle basal sedimentary strata increased most in Alfalfa, Grant, and Woods

Counties of northern Oklahoma from 2010

– 2013, while SWD volumes in Kay, Lincoln, and

Creek C ounties decrease d substantially in that same time period. S eismic activity increased most

in Lincoln, Grant, and Seminole Counties from 2010 & 2011 to 2012 & 2013. A comparison of

t emporal trends in SWD volumes for wells completed in the Arbuckle or Basement zones versus

county

- scale seismicity exhibit a variety of direct and inverse correlations.Oklahoma Geological Survey OF1

- 2014

2

1. Introduction

Petroleum production began in Oklahoma

before 1900 and has been continuously

produced for more than 100 years, with oil

peaking at ~278 million barrels of oil

(MMBO) in 1927 and gas production

peaking at ~399 million barrels of oil

equivalent (MMBOE) in 19 90 ( Murray and

Holland 2014 ) . Modest volumes of oil were

produced in Oklahoma for several decades,

but a resurgence in production has occurred

because of technological innovation and

economic drivers. More than 26% of

Oklahoma’s petroleum wells completed in

2009 were horizontally drilled and

hydraulically fractured, but th e proportion

appears to have increased annually with

more than 43% being horizontal in 2011

( Murray 2013 ) . Higher production has also

occurred from unconventional shale plays

and from conventional sandstone and

carbonate reservoirs ( Murray and Holland

2014 ) . Crude

- oil production averaged 76.7

MMBO in Oklahoma from 2010

– 2012,

ranking as the 5th highest producing U.S.

state ( EIA 2014a ) . Gross natural

- gas

production averaged 89.3 MMBOE in

Oklahoma from 2010

– 2012, ranking as the

5th highest producing U.S. state ( EIA

2014b )

. Concurrent with higher annual statewide

petroleum production is a higher annual

statewide co

- production of water. By

multiplying H 2 O :oil ratio by oil production

and H 2 O :gas ratio by oil

- equivalent gas

production, Murray (2013) estimated

Oklahoma’s statewide co

- produced water

volumes to range from 811

– 925 million

barrels (MMbbl) from 2000

– 2011.

D ewatering from the Hunton Lime and other

plays, such as the Mississippian of southern

Kansas and northern Oklahoma, produce

large volumes of water per unit of oil or gas.

Petroleum production from the

Mississippian has been highest in Woods,

Alfalfa, Grant, Kay, and Osage counties in northern Ok lahoma, so co

- production of

water may be potentially higher in this

region.

1.1. Underground Injection Control (UIC)

Well Designations

The underground injection control (UIC)

program was implemented by the U.S.

Environmental Protection Agency (EPA) in

the 1980s to manage and regulate fluid

injections into the subsurface. Six UIC well

designations (Class I, II, III, IV, V, and VI)

are used to manage injections from various

industries. The EPA maintains regulatory

authority over subsurface fluid injection but

may delegate authority of Class II wells to

state agencies. The Oklahoma Corporation

Commission (OCC) is delegated authority

over Class II UIC wells, except in Osage

County (i.e., Osage Nation) where EPA

maintains authority. Current regulatory

controls over Cl ass II UIC wells were

designed to protect potable

- water sources

from contamination.

Class II UIC wells are used for two basic

purposes in the oil and gas sector, enhanced

oil

- recovery injection ( i.e., EORI or 2R) and

salt

- water disposal ( i.e., SWD or 2D). UIC

wells of the 2R type are designed to inject

fluids (water and/or CO 2 ) into the subsurface

to mobilize oil and/or gas into production

wells. During 2R injection, pressure across

the field is monitored so as not to exceed

virgin pressure conditions. UIC wells of the

2D type are designed to dispose of brine

water that was co

- produced with oil and gas.

These 2D wells ideally function on a

vacuum or require low wellhead

- injection

pressures. The term ‘injection’ is used

throughout this report because the well s are

part of the UIC program; however, use of

the term injection does no t imply high

pressure such as would be used for hydraulic

fracturing during well completion.Oklahoma Geological Survey OF1

- 2014

3

1.2. Potential for Induced Seismicity from

Fluid Injection

Fluid injections, including 2R ( Davis and

Pennington 1989 ) and 2D ( Horton 2012

, Keranen et al. 2013

, Nicholson and Wesson

1990 ) have been correlated to seismici ty and

are assumed to reduce normal stress so that

movement occurs along a pre

- existing fault

( Healy et al. 1968

, NRC 2012

, Raleigh et al.

1976 )

. Some of the largest magnitude

earthquakes correlated with 2D injections

were centered in the midcontinent states of

Arkansas, Oklahoma, and Texas ( Frohlich

2012

, Horton 2012

, Keranen et al. 2013 )

. Regardless of potential correlations,

research on the topic of induced seismicity

recognizes the uncertainty and the difficulty

in distinguishing between natural or induced

seismic events. Major limitations of

previous studies relate to the unknown

quality of UIC data including x

- y location, z

elevation, zone of completion, volume, and

pressure. Integrated hydrogeologic,

structural ge ologic, and seismologic studies

are required because mechanisms for fluid

injection induced seismicity are related to

stresses and strength of faults, hydraulic

properties of injection zones, and pressure

diffusion ( Ellsworth 2013

, Holland 2013 )

.

1.3. Objectives

Absent from the fluid

- injection induced

seismicity literature are broad

- scale

perspectives on fluid

- injection volumes and

pressures or accurate reporting of geologic

intervals that receive those f luids. The

objectives of this research were to compile

and summarize water ( e.g., brackish or

saltwater ) injection volumes and wellhead

injection pressures for Class II UIC wells in

Oklahoma by geologic completion zone,

examine spatial and temporal trends for

subsurface injection from 2010

– 201 3

, and

map annual seismic activity from 2010

–

2013. 2. Methods

Because disparate data for Class II UIC

program wells in Oklahoma were reported to

OCC and EPA for the 2010

– 201 3

timeframe, multiple databases were

designed and maintained during the course

of this research. American Petroleum

Institute (API) unique identifiers for wells

(i.e., API number) were used to manage data

reported to OCC, while EPA assigned

inventory number was used for UIC wells in

Osage County, Oklahoma.

2.1. Compile UIC Well Locations and

Injection Data

Monthly fluid

- injection volumes and

pressures for Class II UIC wells were

obtained from the OCC ( Lord 2014

, Lord

2012

, OCC 2014a

, OCC 2014b ) and used to

create a relational database for wells in

Oklahoma (i.e., Oklahoma UIC database),

excluding Osa ge County, from 2010

– 201 3

. Records were managed using API number

when appending data to the Oklahoma UIC

database.

Fluid injection data for Class II UIC wells

in Osage County were obtained from the

EPA District 6 office and used to create a

relational Osag e UIC database. Maximum

monthly injection volumes per well were

provided by EPA, so annual injection

volumes were ‘overestimated’ by

multiplying maximum monthly injection

volume by 12 (months per year). UIC well

records in the Osage UIC database were

manag ed using an inventory number

assigned by the EPA.

2.2. Quality Assurance Quality Control

(QAQC) of UIC Data

Annual injection volumes and injection

pressures in the Oklahoma UIC database

were compared to scanned ‘Form 1012A:

Annual Fluid Injection Reports’ that were

submitted to the OCC by UIC operators.

A nnual volume recorded in the OklahomaOklahoma Geological Survey OF1

- 2014

4

UIC database

, before the quality assurance

quality control (QAQC) check

, included

carbon dioxide ( CO 2 ) in units of MCF or

Liquefied Petroleum Gas ( LPG ) in units of

barrels in addition to water volumes. Thus,

annual volumes were modified in the

Oklahoma UIC database to represent only

water volumes. In other cases, the operators

reported a barrels per day (BPD) injection

rate instead of barrels per month (BPM)

which, when annualized, was

underrepresenting injection volume.

The Osage UIC database did not go

through a QAQC check because more

detailed records were only accessible in

hard

- copy at the Bureau of Indian Affairs

(BIA) office in Pawhuska, Oklahoma and

would require an even greater time

commitment

.

2.3. Attribute Injection Zones for Wells

Well

- completion data for Oklahoma UIC

database wells were obtained from the OCC

well database and interactive web

- site ( OCC

2014c ) . Injection zones were represented

using twelve categories after Murray and

Holland (2014) : Permian, Virgilian,

Missourian, Desmoinesian, Atokan

Morrowan, Mississippian, Woodford,

Devonian to Middle Ordovician (Dev to Mid

Ord), Arbuckle, Basement, Multiple

Undifferentiated, and Other or Unspecified.

‘Producing’ or ‘injection’ formation(s) were

correlated to the appropriate zone based on

the Stratigraphic Guide to Oklahoma Oil and

Gas Reserv oirs ( Boyd 2008 ) . When

producing or injection formation was not

specified in the Oklahoma UIC databases,

the completion reports (e.g., OCC’s Form

1002A) or other digitally accessible records

were examined for each API number in

Oklahoma. The injection formation(s) for

the most recent completion of each API

number was determined, when possible, and

added as an attribute to the Oklahoma UIC

database. When records indicated that the

injection interval consisted of multiple groups o r formations (e.g., Bartlesville and

Dutcher) from more than one zone, then the

well was attributed as ‘Multiple

Undifferentiated.’ When records indicated

that a formation (e.g., Cretaceous Niobrara)

other than the ten designated zones was used

for injecti on or the target formation was not

discernible, then the well was attri buted as

‘Other or Unspecified’. UIC well records in

the Oklahoma UIC database were also

attributed with maximum injection depth

based on deepest perforated or open

- hole

interval.

2.4. Summarize Volumes by Zone and County

Class II UIC wells were selected (i.e.,

queried) from the Oklahom a UIC database.

A nnual injection volumes were summed for

each year from 2010

– 201 3, a fter grouping

the selected wells by injection zone (e.g.,

Permian, Vir gilian)

, injection type (i.e., 2R

or 2D), and county . From these queries, total

water

- injection volumes were estimated for

each zone by county from 2010

– 201 3

.

2.5. Obtain Earthquake Data for 2010

– 2013

Earthquake data including date, xy

location, depth, and magn itude were

downloaded from the Oklahoma Geological

Survey (OGS) Geophysical Observatory

earthquake catalog

(http://www.okgeosurvey1.gov/pages/earthq

uakes/catalogs.php). Data were sorted and

counted by year of origin, magnitude, or

depth and plotted versus time in Microsoft

Excel, or spatial location was plotted in

ArcGIS. UIC well and earthquake locations

were mapped in relation to Oklahoma

regional fault systems that were previously

published as part of a study of the geologic

provinces of Oklahoma ( Northcutt and

Campbell 1995 ) , and for the Cherokee

Platform geologic province by the Kansas

Geological Survey ( Nodine

- Zeller and

Thompson 1977 )

.Oklahoma Geological Survey OF1

- 2014

5

3. Results and Discussion

Limited access to Osage County UIC

well completion forms and annual fluid

injection reports did not allow for

confirmation of zones of injection and

resulted in extreme overestimation of annual

injection volumes. Because Osage County

UIC well data have a g reater degree of

uncertainty, they were not critically

analyzed or represented in all data tables or

figures in this report

. In the Oklahoma UIC database, a well is

referred to as ‘active’ if, for any given year,

at least 1 bbl of water was reportedly

inje cted. A query of the QAQC checked

Oklahoma UIC database indicates that 83 90

, 8 26 5, 8738, and 8 239 UIC wells were

‘active’ from 2010

– 2013 , respectively. Form

1012As for the year 2011 were unavailable

for at least 28 0 UIC wells or 3. 3 % and 3. 2 %

of those that were active in 2010 and 2012,

respectively. This data gap is believed to be

due to Form 1012A submittals changing

from hard

- copy in 2010 to electronic in

2011. Additional uncertainties and data gaps

undoubtedly exist in the Oklahoma UIC

database, f

or exam ple, estimated 2D+2R

water injection volumes for 2010 in

Oklahoma (excluding Osage County) were

reported as 1921 MMbbl in a 2013 paper

( Murray 2013 ) but the estimated 2D+2R

water injection volume for 2010 in

Oklahoma (excluding Osage County) i s

1837 MMbbl in this report

. P resumably

additional QAQC will lead to more accurate

future repor ts of injection volumes,

pressures, and depths.

3.1. Highest Volume Class II UIC Wells

An injection rate exceeding 150,000

BPM (i.e., 1.8 MMbbl per year) was

selected to represent a ‘ high volume UIC

well ’ because it was notable in the Barnett

Shale region of Johnson County, Texas

where 33.3% of the UIC wells exceeded this

injection rate and potential induced seismicity was reported ( Frohlich 2012 )

. Oklahoma, excluding Osage County, had

32 97 , 3 221

, 3507, and 3 197 active 2D wells

from 2010

– 201 3 , respectively

, which are

symbolized by relative annual i njection

volume in Figures 1

– 4 . A small fraction,

1 74 out of 3 197 ( 5.44 %) of the 2D wells

shown in Figure 4 were high volume UIC

wells during 201 3

. Oklahoma, excluding

Osage County, had 5 093

, 5044

, 5231, and

5 042 active 2R wells from 2010

– 2013,

respectively , which are symbolized by

relative annual injection volume in Figures

5

– 8 . Only 11 out of the 5 042 (0.2 2 %) active

2R wells shown in Figure 8 were high

volume UIC wells during 2013.

3.2. SWD Wells and Volumes by Geolo gic

Zone of Completion

Oklahoma, excluding Osage County, had

more than 3 2 00 active SWD (i.e., 2D ) wells

from 2010

– 2013 (Table 1). The low number

of active SWD wells during 2013 relative to

2012 is because an estimated 296 annual

fluid injection reports wer e not yet available

from OCC.

Table 1 Number of active SWD (i.e., 2D) wells in

Oklahoma

, by zone of completion

Zone Active

Wells

in 2010 Active

Wells

in 2011 Active

Wells

in 2012 Active

Wells

in 2013

Permian 353 344 377 340

Virgilian 225 216 226 204

Missourian 286 268 280 259

Desmoinesian 618 567 602 537

Atokan

Morrowan 281 265 264 230

Mississippian 126 126 124 109

Woodford 4 4 3 3

Dev to Mid

Ord 462 448 469 425

Arbuckle 477 537 667 667

Basement 7 8 11 10

Multiple

Undiff 175 169 197 163

Other Or

Unspec 283 269 287 250

Total 3297 3221 3507 3197Oklahoma Geological Survey OF1

- 2014

6

Records of Class II UIC well volumes are

believed to be unreliable and incomplete

before the year 2009, so it is uncertain

whether present Class II UIC volumes

exceed historic Class II UIC volumes. For

example, much larger volumes of oil and gas

were produced in the 1980s and 1990s;

therefore, comparable volumes of water may

have been co

- produced at that time.

Table 2 Volume of water injected int o SWD (i.e., 2D)

wells in Oklahoma, by zone of completion

Zone MMbbl

H 2 O

Injected

in 2010 MMbbl

H 2 O

Injected

in 2011 MMbbl

H 2 O

Injected

in 2012 MMbbl

H 2 O

Injected

in 2013

Permian 51.1 68.2 82.3 77.7

Virgilian 30.5 32.0 40.0 34.0

Missourian 26.5 24.7 27.0 29.1

Desmoinesian 34.1 33.3 34.7 30.7

Atokan

Morrowan 46.8 46.7 52.3 46.4

Mississippian 9.3 9.5 9.4 7.9

Woodford 0.4 0.4 0.2 0.3

Dev to Mid

Ord 101.8 99.7 105.7 102.9

Arbuckle 449.2 523.1 568.2 739.1

Basement 0.8 0.6 1.4 0.7

Multiple

Undiff 114.4 136.6 131.0 111.7

Other Or

Unspec 13.5 15.8 14.6 12.8

Total 878.3 990.8 1066.8 1193.3

A nnual statewide 2D water injection

volumes were 878.3, 990.8, 1066.8, and

1193.3 MMbbl from 2010

– 2013,

respectively (Table 2 and Figures 9

– 12 ).

SWD (i.e., 2D) wells completed in the

Arbuckle, predominantly carbonate,

received the highest annual volumes of

saltwater with 44 9.2, 523.1, 568.2, and

739.1 MMbbl from 2010

– 2013,

respectively, (Table 2 and Figures 9

– 12 )

which corresponds to a 289.9 MMbbl or

64.5 % increase from 2010 to 201 3

. 3.3. EORI Wells and Volumes by Geologic

Zone s of Completion

Oklahoma, excluding Osage County, had

more than 5 000 active EORI (i.e., 2 R ) wells

from 2010

– 2013 ( Table 3 ). The relatively

low number of active wells for 2013 is

because an estimated 165 EORI (i.e., 2R)

well annual fluid injection reports were not

yet available at OCC , assuming that those

reported in 2012 are still active

.

Table 3 Number of active EORI (i.e., 2R) wells in

Oklahoma, by zo ne of completion

Zone Active

Wells

in 2010 Active

Wells

in 2011 Active

Wells

in 2012 Active

Wells

in 2013

Permian 344 348 358 351

Virgilian 91 87 99 82

Missourian 1016 1004 1045 1021

Desmoinesian 1894 1854 1930 1883

Atokan

Morrowan 692 713 725 692

Mississippian 130 131 129 125

Woodford 4 3 3 4

Dev to Mid

Ord 402 419 423 389

Arbuckle 20 23 22 21

Basement 0 0 1 1

Multiple

Undiff 211 195 213 214

Other Or

Unspec 289 267 283 259

Total 5093 5044 5231 5042

Table 4 Volume of water injected into EORI (i.e., 2R)

wells in Oklahoma, by zone of completion

Zone MMbbl

H 2 O

Injected

in 2010 MMbbl

H 2 O

Injected

in 2011 MMbbl

H 2 O

Injected

in 2012 MMbbl

H 2 O

Injected

in 2013

Permian 33.8 40.9 43.9 43.8

Virgilian 12.9 11.2 11.9 9.6

Missourian 226.1 234.5 269.1 253.0

Desmoinesian 283.0 290.4 296.9 295.0

Atokan

Morrowan 155.4 168.6 181.5 172.9

Mississippian 37.5 38.4 36.4 34.9

Woodford 0.1 0.2 0.2 0.2

Dev to Mid

Ord 116.0 153.2 204.7 163.4Oklahoma Geological Survey OF1

- 2014

7

Arbuckle 10.4 14.9 14.7 14.2

Basement 0.0 0.0 0.0 0.0

Multiple

Undiff 49.3 48.2 51.6 56.9

Other Or

Unspec 34.3 32.5 37.4 36.1

Total 958.8 1033.0 1148.5 1080.0

Oklahoma annual statewide, excluding

Osage County, volume of EORI (i.e., 2R )

water injection was 958.8, 1033.0, 1148.5,

and 1080.0 MMbbl from 2010

– 201 3

, respectively (Table 4 and Figures 9

– 12 )

. EORI ( i.e., 2R) wells completed in the

Desmoinesian, compris ed mostly of

sandstones, received the highest annual

volumes of water with 283.0, 290.4, 296.9,

and 295.0 MMbbl from 2010

– 201 3

, respectively ( Table 4 and Figures 9

– 12 ).

3.4. T emporal T

rends in SWD by County

Petroleum production, co

- production of

water, and SWD vary substantially in space

and time; therefore, it is best to view trends

on a smaller spatial scale (i.e., county

- scale)

.

Table 5 SWD (i.e., 2D) volumes by county

County MMbbl

of SWD

in 2010 MMbbl

of SWD

in 2011 MMbbl

of SWD

in 2012 MMbbl

of SWD

in 2013

Alfalfa 18.7 61.8 36.8 225.5

Beaver 3.0 5.5 8.3 13.0

Beckham 7.0 11.0 10.8 8.9

Blaine 4.3 8.6 6.6 3.5

Caddo 5.2 6.0 6.9 6.4

Canadian 6.3 7.7 10.1 9.6

Carter 9.1 9.6 11.3 12.4

Cleveland 1.3 1.2 1.1 0.6

Coal 11.3 7.9 6.7 3.8

Creek 46.4 37.7 44.2 28.9

Custer 0.5 1.4 4.3 3.3

Dewey 16.3 21.9 29.4 29.4

Ellis 3.0 5.8 7.3 10.4

Garfield 11.9 12.9 14.2 21.0

Garvin 9.8 12.7 16.3 14.9

Grady 2.2 3.3 3.9 3.7

Grant 8.2 24.2 19.6 54.2

Harper 4.4 3.4 3.1 2.7

Hughes 9.1 13.4 11.9 11.3

Kay 72.1 93.9 97.5 43.0

Kingfisher 5.7 6.4 5.4 7.7

Latimer 0.8 0.8 0.7 0.7

Le Flore 0.3 0.3 0.2 0.2

Lincoln 73.1 67.7 58.9 52.0 Logan 5.2 7.2 8.7 10.2

Love 0.3 0.3 0.3 0.3

McClain 1.6 2.3 3.5 4.0

McIntosh 3.2 3.5 2.6 1.6

Major 7.9 8.9 8.3 7.2

Murray 5.4 9.7 10.4 8.5

Muskogee 0.7 0.6 0.2 0.2

Noble 33.0 28.6 39.0 46.8

Nowata 0.8 0.5 0.8 2.0

Okfuskee 15.0 19.1 20.4 14.2

Oklahoma 61.8 65.8 74.8 67.2

Okmulgee 3.2 3.4 3.1 2.6

Pawnee 8.5 9.1 12.3 20.4

Payne 12.2 13.1 16.7 16.9

Pittsburg 1.4 2.2 4.3 3.1

Pontotoc 14.8 16.8 20.9 19.2

Pottawatomie 49.9 49.0 48.8 46.0

Roger Mills 6.5 13.1 14.3 6.3

Seminole 88.9 87.9 103.6 88.1

Stephens 5.1 5.1 5.7 3.9

Texas 2.1 2.2 3.9 4.4

Tillman 1.0 1.0 1.2 1.5

Tulsa 1.4 1.4 1.4 1.3

Wagoner 0.7 0.6 0.8 0.6

Washington 1.7 1.6 1.6 1.5

Washita 5.0 5.4 4.7 3.1

Woods 45.5 60.3 67.9 72.1

Woodward 7.2 7.2 5.8 3.2

Table 5 lists the 52 counties in Oklahoma

that had a cumulative volume of ≥ 1 MMbbl

water injected into Class II SWD wells from

2010

– 2013. R eported a nnual volumes of

SWD (i.e., 2D ) increased for 2 8 out of the

5 2 counties from 2010 to 201 3

. Annual and

county

- scale SWD volumes are also

illustrated as charts on Figures 1

– 4

. Alfalfa,

Grant, and Woods Counties had the greatest

increases of 206.8, 46.0, and 26.6 M Mbbls,

respectively

.

3.5. Injection Depths and Pressures of S WD

SWD wells are designed to be cased,

with steel and cement seals, below

underground sources of drinking water

(USDW). The injection interval is

co mpleted as open hole or the liner may be

perforated within the target injection zone.

Depth s of injection interval s vari ed from

356

– 18,88 6 ft below the land surface for

active SWD (i.e., 2D) wells. The shallow est

active SWD (i.e., 2D ) well (named Jamison )

injects into the Permian zone in StephensOklahoma Geological Survey OF1

- 2014

8

County, Ok lahoma to a depth of 356 ft. The

deepest active SWD (i.e., 2D ) well (named

Tipton) injects into the Atokan

- Morrowan

zone in Roger Mills County, Ok lahoma to a

depth of 18,886 ft. SWD (i.e., 2D ) wells

completed in the ‘Other or Unspecified’

zone had the lowest median depth of 1785.5

ft , while SWD (i.e., 2D) wells compl eted in

the Arbuckle zone had the deepest median

depth of 6852 ft (shown in Figure 13 ).

Wellhead injection pressure for active

SWD (i.e., 2D ) wells in the Basement had

the highest median value of 2 45 psi in 2010,

while the Atokan

- Morrowan, Dev to Mid

Ord, and Arbuckle zone wells had a median

injection pressure of <0 psi (Table 6 and

Figures 14

– 17 )

. Wellhead i njection pressure

data are of unknown quality because a large

percentage of SWD (i.e., 2D ) wells were

reportedly operating on a vacuum, but were

reported as injecting at 0 psi rather than <0

psi.

Table 6 Median wellhead pressure s reported for active

SWD (i.e., 2D) wells, by completion zone

Zone Median

psi in

2010 Median

psi in

2011 Median

psi in

2012 Median

psi in

2013

Permian 188 200 171 167

Virgilian 200 200 200 216

Missourian 125 120 117 105

Desmoinesian 100 100 91 82

Atokan

Morrowan 10 0 0 0

Mississippian 50 50 50 50

Woodford 11 20 40 40

Dev to Mid

Ord 0 0 0 10

Arbuckle 0 0 0 5

Basement 245 186 100 231

Multiple

Undiff 150 150 125 135

Other Or

Unspec 50 50 50 50

3.6. Temporal Trends in EORI by County

Secondary oil production can be realized

using enhanced oil recovery (EOR),

whereby fluids (e.g., H 2 O or CO 2 ) are injected into an EORI well. ‘Water flooding’

is a common practice in several Oklahoma

counties. Table 7 lists the 38 counties in

Oklahoma that had a cumulative volume of

≥1 MMbbl water injected into EORI wells

from 2010

– 2013. R eported a nnual water

(e .g., brackish or saltwater) volumes of

EORI (i.e., 2 R) increased for 2 3 out of the

38 counties from 2010 to 2013. Pontotoc,

Carter, and Garvin Counties had the greatest

increases of 37.9

, 14.8 , and 9.8 MMbbls,

respectively.

Table 7 EORI (i.e., 2R) volumes by county

County MMbbl

of EORI

in 2010 MMbbl

of EORI

in 2011 MMbbl

of EORI

in 2012 MMbbl

of EORI

in 2013

Alfalfa 0.6 0.9 0.9 1.0

Beaver 6.0 6.6 6.1 6.8

Bryan 0.2 0.2 0.3 0.3

Caddo 7.4 7.9 8.0 9.4

Carter 241.2 247.5 274.5 256.0

Cimarron 0.2 0.3 0.3 0.3

Cleveland 0.4 0.4 0.4 0.1

Cotton 0.5 0.5 0.6 0.5

Creek 69.8 73.0 76.5 71.7

Dewey 15.0 14.6 15.0 14.1

Garfield 0.3 0.3 0.4 0.4

Garvin 26.0 32.8 34.3 35.8

Grady 10.2 11.3 12.2 9.9

Grant 3.7 3.1 4.0 2.7

Jefferson 1.0 1.0 1.8 1.1

Kay 6.6 7.1 7.2 6.0

Lincoln 7.2 7.9 6.2 5.7

Logan 0.2 0.2 0.3 0.3

Love 0.3 0.3 0.3 0.3

McClain 0.7 2.2 0.2 0.0

Murray 4.1 10.4 12.0 11.4

Muskogee 0.4 0.3 0.4 0.1

Noble 1.2 1.2 1.3 1.5

Nowata 13.6 13.7 13.2 13.5

Okfuskee 3.0 4.5 5.5 5.1

Oklahoma 4.0 4.0 5.2 5.7

Okmulgee 0.9 0.9 0.4 1.4

Pawnee 3.9 3.7 4.1 4.6

Payne 0.9 0.9 0.9 0.8

Pittsburg 0.5 0.7 0.7 0.5

Pontotoc 79.4 108.3 156.6 117.2

Pottawatomie 3.2 4.3 3.7 3.6

Seminole 26.7 27.5 28.7 26.5

Stephens 42.3 47.2 51.1 45.7

Texas 34.3 34.6 36.3 40.0

Wagoner 0.2 0.2 0.3 0.4

Woods 4.9 5.1 5.7 3.8

Woodward 7.1 7.7 7.2 7.0Oklahoma Geological Survey OF1

- 2014

9

3.7. Seismic Activity in Oklahoma

Seismic activity has increased

significantly in recent years, with about 109

magnitude 3.0 or gre ater earthquakes

occurring in 2013 and more than 500

magnitude 3.0 or greater earthquakes

occurring in 2014 ( OGS 2014 )

. From 2010

- 2012, t he majority of earthquakes were

located in central Oklahoma (Figures 1 8

–

20 ) , but numerous earthquakes occurred in

Grant, Alfalfa, and Woods Coun ties of

north

- central Oklahoma during 2013 (Figure

21 )

. Median depth for earthquakes (i.e.,

focal depth or origin) in Oklahoma was

about 12,303 ft (~3.75 km), and more than

75% of focal points were at depths of more

than 9842 ft (~2.5 km), as shown in Figure

22

. Because SWD (i.e., 2D ) wells injecting

into the Arbuckle zone are in direct contact

with or close proximity to basement rock,

they may be the most relevant for

comparison to seismic activity, which is

typically focused on basement fault

networks ( Zhang et al. 2013 )

. Changes in

seismicity were observed in numerous

counties of Oklahoma having active Class II

SWD wells completed in the Arbuckle or

Basement zone s . A spatiotemporal

comparison was made between change in

SWD volumes into the Arbuckle or

Basement zones (2013 & 2012 versus 2011

& 2010) and change in seismicity (2013 &

2012 versus 2011 & 201 0) at a county

- scale

. These data were organized into four

quadrants on Figure 23 , whereby Quad A

includes counties (e.g., Oklahoma) with an

increase in SWD (+SWD) and a decrease in

number of earthquakes (

- EQ), Quad B

includes counties (e.g., Grant and Alfa lfa)

with an increase in SWD ( +SWD ) and an

increase in number of earthquakes ( +EQ )

, Quad C includes counties (e.g., Lincoln)

with a decrase in SWD (

- SWD ) and an

increase in number of earthquakes ( +EQ )

, and Quad D includes counties (e.g., Garvin) with a dec rease in SWD (

- SWD ) and a

decrease in number of earthquakes (

- EQ )

from 2010

– 2013. Those counties (e.g.,

Alfalfa, Coal, Garvin, Grant, Kay, Lincoln,

Oklahoma, Payne, Seminole, and Woods)

that deviate substantially from the origin in

Figure 23 would be inter esting for m ore

detailed studies of geologic factors that may

affect seismicity.

4. Future Directions

Measurement of pre

- injection hydraulic

conditions and formation pressure, along

with increased temporal resolution of

injection rates and pressures are criti cal for

understanding the dynamic relationships

between fluid injection and seismicity

( Ellsworth 2013 ) . Thorough evaluation of

the presence or absence of faulting near

fluid

- injection wells ( Frohlich 2012 ) is also

a priority for understanding potential for

induced sei smicity.

Reasonable estimates of field

- scale

historic and future fluid

- injection a nd

withdrawal volumes must be made for all

production or injection zones so that

production versus injection versus seismicity

can be put into the proper perspective

. Integrated hyd rogeologic, structural

geologic, and seismologic datasets may then

be evalu ated to establish mechanisms by

which fluid injection affect s por e pressure

along a fault plane.

These integrated scientific studies c ould

be useful for the development of adaptable

regulatory requirements and best

management practices for Class II wells

m anaged in the underground injection

control program

.

5. References

Boyd DT (2008) Stratigraphic Guide to

Oklahoma Oil and Gas Reservoirs.

Oklahoma Geological Survey,

SP2008

- 1. Norman, OK. pp. 2.

Davis SD, Pennington WD (1989) Induced

seismic deformation in the CogdellOklahoma Geological Survey OF1

- 2014

10

oil field of west Texas. Bulletin of

the Seismological Society of

America 79:1477

- 1495

EIA (2014a) Field Production of Crude Oil

in the United States.

http ://www.eia.gov/dnav/pet/pet_crd

_crpdn_adc_mbbl_a.htm . Cited Jul

22

EIA (2014b) Natural Gas Gross

Withdrawals and Production.

http://www.eia.gov/dnav/ng/ng_prod

_sum_dcu_nus_m.htm . Cited Jul 1

Ellsworth WL (2013) Injection

- Induced

Earthquakes. Science 341:142

- 149

DOI 10.1126/science.1225942

Frohlich C (2012) Two

- year survey

comparing earthquake activity and

injection

- well locations in the

Barnett Shale, Texas. Proceedings of

the N ational Academy of Sciences

109:13934

- 13938 DOI

10.1073/pnas.1207728109

Healy JH, Rubey WW, Griggs DT, Raleigh

CB (1968) The Denver Earthquakes.

Science 161:1301

- 1310 DOI

10.2307/1725684

Holland AA (2013) Earthquakes Triggered

by Hydraulic Fracturing in So uth

Central Oklahoma. Bulletin of the

Seismological Society of America

103:1784

- 1792 DOI

10.1785/0120120109

Horton S (2012) Disposal of Hydrofracking

Waste Fluid by Injection into

Subsurface Aquifers Triggers

Earthquake Swarm in Central

Arkansas with Poten tial for

Damaging Earthquake.

Seismological Research Letters

83:250

- 260 DOI

10.1785/gssrl.83.2.250

Keranen KM, Savage HM, Abers GA,

Cochran ES (2013) Potentially

induced earthquakes in Oklahoma,

USA: Links between wastewater

injection and the 2011 Mw 5.7 e arthquake sequence. Geology

41:699

- 702 DOI 10.1130/g34045.1

Lord C (2012) Monthly injection volumes

for Class II Underground Injection

Control (UIC) wells in Oklahoma,

2011. In: Oil and Gas Division,

Oklahoma Corporation Commission,

Oklahoma City, OK.

Lord C (2014) Monthly injection volumes

for Class II Underground Injection

Control (UIC) wells in Oklahoma.

In: Oil and Gas Division, Oklahoma

Corporation Commission, Oklahoma

City, OK.

Murray KE (2013) State

- Scale Perspective

on Water Use and Production

Associated with Oil and Gas

Operations, Oklahoma, U.S. Environ

Sci Technol 47:4918

- 4925 DOI

10.1021/es4000593

Murray KE, Holland AA (2014) Inventory

of Class II Underground Injection

Control Volumes in the

Midcontinent. Shale Shaker 65:98

-

106

Nicholson C, Wesson RL (1990) Earthquake

hazard associated with deep well

injection

- A report to the U.S.

Environmental Protection Agency.

US Geological Survey Bulletin 1951.

pp. 74.

Nodine

- Zeller DE, Thompson TL (1977)

Age and structure of subsurface beds

in Cherokee C ounty, Kansas:

Implications from endthyrid

foraminifera and conodonts. Kansas

Geological Survey, Lawrence, KS

Northcutt RA, Campbell JA (1995)

Geologic provinces of Oklahoma.

Oklahoma Geological Survey Open

File Report (OF5

- 95)

NRC (2012) Induced Seismic ity Potential in

Energy Technologies. National

Academy of Sciences, Washington,

DCOklahoma Geological Survey OF1

- 2014

11

OCC (2014a) UIC Injection Volumes 2012.

http://www.occeweb.com/og/ogdataf

iles2.htm . Cited Nov 25

OCC (2014b) UIC Injection Volumes 2013.

http://www.occeweb.com/og/ogdataf

iles2.htm . Cited Nov 25

OCC (2014c) Well Data System.

http://www.occpermit.c om/WellBro

wse/Home.aspx . Cited various dates

OGS (2014) Leonard Geophysical

Observatory Catalog.

http://www.okgeosurvey1.gov/pages/

earthquakes/catalogs.php . Cited 1

Sep 2014 Raleig h CB, Healy JH, Bredehoeft JD

(1976) An experiment in earthquake

control at Rangely, Colorado.

Science 191:1230

- 1237

Zhang Y, Person M, Rupp J, Ellett K, Celia

MA, Gable CW, Bowen B, Evans J,

Bandilla K, Mozley P, Dewers T,

Elliot T (2013) Hydrogeologic

Co ntrols on Induced Seismicity in

Crystalline Basement Rocks Due to

Fluid Injection into Basal Reservoirs.

Ground Water 51:525

- 538 DOI

10.1111/gwat.12071

Abbreviations , Units, and Definitions

2D: Class II Disposal (aka SWD)

2R: Class II Recovery (aka EORI)

API: American Petroleum Institute

bbl: barrels

BIA: Bureau of Indian Affairs

BPD: Barrels Per Day

BPM: Barrels Per Month

BWPM: Barrels of Water Per Month

CO 2 : carbon dioxide

EOR: Enhanced O il Recovery

EORI: Enhanced Oil Recovery Injection

(aka 2R)

EPA: Environmental Protection Agency high volume UIC well: exceeding 150,000

BWPM or 1.8 MMbbl per year

LPG: Liquefied Petroleum Gas

MCF: thousand cubic feet

MMbbl: Millions of barrels

OCC: Oklaho ma Corporation Commission

OGS: Oklahoma Geological Survey

psi: pounds per square inch

SWD: SaltWater Disposal (aka 2D)

QAQC: Quality Assurance Quality Control

UIC : Underground Injection Control

USDW:Underground Sources of Drinking

WaterOklahoma Geological Survey OF1

- 2014

12

Figure 1 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells (i.e., 2D) during 201 0

. Chart of SWD well volumes in 2010 by county

.Oklahoma Geological Survey OF1

- 2014

13

Figure 2 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells (i.e., 2D) during 201 1

. Chart of SWD well volumes in 2011 by county

.Oklahoma Geological Survey OF1

- 2014

14

Figure 3 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells (i.e

., 2D) during 201 2

. Chart of SWD well volumes in 2012 by county

.Oklahoma Geological Survey OF1

- 2014

15

Figure 4 Map of SWD wells and relative volumes of water injected into SWD Class II UIC wells (i.e., 2D) during 201 3

. Chart of SWD well volumes in 2013 by county

.Oklahoma Geological Survey OF1

- 2014

16

Figure 5 Map of EORI wells and relative volumes of water injected into EORI Class II UIC wells (i.e., 2 R ) during 201 0

. Chart of EORI well volumes in 2010 by county.Oklahoma Geological Survey OF1

- 2014

17

Figure 6 Map of EORI wells and relative volumes of water injected into EORI Class II UIC wells (i.e., 2 R ) during 201 1

. Chart of EORI well volumes in 2011 by county.Oklahoma Geological Survey OF1

- 2014

18

Figure 7 Map of EORI wells and relative volumes of water injected into EORI Class II UIC wells (i.e., 2 R ) during 201 2

. Chart of EORI well volumes in 2012 by county.Oklahoma Geological Survey OF1

- 2014

19

Figure 8 Map of EORI wells and relative volumes of water injected into EORI Class II UIC wells (i.e., 2 R ) during 201 3

. Chart of EORI well volumes in 2013 by county.Oklahoma Geological Survey OF1

- 2014

20 Figure 9 Chart of UIC well volumes in 2010 by geologic zone of completion.Oklahoma Geological Survey OF1

- 2014

21 Figure 10 Chart of UIC well volumes in 2011 by geologic zone of completion.Oklahoma Geological Survey OF1

- 2014

22 Figure 11 Chart of UIC wel l volumes in 2012 by geologic zone of completion.Oklahoma Geological Survey OF1

- 2014

23 Figure 12 Chart of UIC well volumes in 2013 by geologic zone of completion.Oklahoma Geological Survey OF1

- 2014

24 Figure 13 Depths, below land surface, for completion intervals of 2010

– 2013 active SWD (i.e., 2D) wells in OklahomaOklahoma Geological Survey OF1

- 2014

25 Figure 14 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2010

Figure 15 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2011Oklahoma Geological Survey OF1

- 2014

26 Figure 16 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2012

Figure 17 Wellhead injection pressure (psi) for active SWD (i.e., 2D) wells in 2013Oklahoma Geological Survey OF1

- 2014

27

Figure 18 Map of earthquakes and relative magnitudes during 201 0

, data from OGS e arthquake catalog

. Chart of >=3.0 magnitude earthquakes in 2010 by month.Oklahoma Geological Survey OF1

- 2014

28

Figure 19 Map of earthquakes and relative magnitudes during 201 1, data from OGS earthquake catalog

. Chart of >=3.0 magnitude earthquakes in 2011 by month

.Oklahoma Geological Survey OF1

- 2014

29

Figure 20 Map of earthquakes and relative magnitudes during 201 2, data from OGS earthquake catalog

. Chart of >=3.0 magnitude e arthquakes in 2012 by month

.Oklahoma Geological Survey OF1

- 2014

30

Figure 21 Map of earthquakes and relative magnitudes during 201 3, data from OGS earthquake catalog

. Chart of >=3.0 magnitude earthquakes in 2013 by month

.Oklahoma Geological Survey OF1

- 2014

31 Figure 22 Number of earthquakes versus depth of focal point for 2000

– 2013Oklahoma Geological Survey OF1

- 2014

32 Figure 23 Spatiotemporal comparison of change in SWD versus change in seismicity at a county

- scale