Induced seismicity and hydraulic fracturing for the recovery of hydrocarbons

Induced seismicity and hydraulic fracturing for the recovery of hydrocarbons
Marine and Petroleum Geology 45 (2013) 171e185
Contents lists available at SciVerse ScienceDirect
Marine and Petroleum Geology
journal homepage: www.elsevier.com/locate/marpetgeo
Review article
Induced seismicity and hydraulic fracturing for the recovery of
hydrocarbons
Richard Davies a, *, Gillian Foulger a, Annette Bindley a,1, Peter Styles b
a
b
Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham DH1 3LE, UK
School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 December 2012
Received in revised form
22 March 2013
Accepted 27 March 2013
Available online 22 April 2013
We compile published examples of induced earthquakes that have occurred since 1929 that have
magnitudes equal to or greater than 1.0. Of the 198 possible examples, magnitudes range up to 7.9. The
potential causes and magnitudes are (a) mining (M 1.6e5.6); (b) oil and gas field depletion (M 1.0e7.3);
(c) water injection for secondary oil recovery (M 1.9e5.1); (d) reservoir impoundment (M 2.0e7.9); (e)
waste disposal (M 2.0e5.3); (f) academic research boreholes investigating induced seismicity and stress
(M 2.8e3.1); (g) solution mining (M 1.0e5.2); (h) geothermal operations (M 1.0e4.6) and (i) hydraulic
fracturing for recovery of gas and oil from low-permeability sedimentary rocks (M 1.0e3.8).
Reactivation of faults and resultant seismicity occurs due to a reduction in effective stress on fault
planes. Hydraulic fracturing operations can trigger seismicity because it can cause an increase in the fluid
pressure in a fault zone. Based upon the research compiled here we propose that this could occur by
three mechanisms. Firstly, fracturing fluid or displaced pore fluid could enter the fault. Secondly, there
may be direct connection with the hydraulic fractures and a fluid pressure pulse could be transmitted to
the fault. Lastly, due to poroelastic properties of rock, deformation or ‘inflation’ due to hydraulic fracturing could increase fluid pressure in the fault or in fractures connected to the fault. The following
pathways for fluid or a fluid pressure pulse are proposed: (a) directly from the wellbore; (b) through new,
stimulated hydraulic fractures; (c) through pre-existing fractures and minor faults; or (d) through the
pore network of permeable beds or along bedding planes. The reactivated fault could be intersected by
the wellbore or it could be 10s to 100s of metres from it.
We propose these mechanisms have been responsible for the three known examples of felt seismicity
that are probably induced by hydraulic fracturing. These are in the USA, Canada and the UK. The largest
such earthquake was M 3.8 and was in the Horn River Basin, Canada. To date, hydraulic fracturing has
been a relatively benign mechanism compared to other anthropogenic triggers, probably because of the
low volumes of fluid and short pumping times used in hydraulic fracturing operations. These data and
analysis should help provide useful context and inform the current debate surrounding hydraulic fracturing technology.
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Induced
Unconventional
Seismic
Earthquake
Fracturing
1. Introduction
It has been known since the 1960s that earthquakes can be
induced by fluid injection. At that time, military waste fluid was
injected into a 3671-m-deep borehole at the Rocky Mountain
Arsenal, Colorado (e.g., Hsieh and Bredehoeft, 1981). This induced
* Corresponding author. Tel.: þ44 7770 704198.
E-mail address: [email protected] (R. Davies).
1
Present address: Working Smart Ltd, Lynton House, Station Approach, Woking
GU22 7PY, UK.
0264-8172/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.marpetgeo.2013.03.016
the so-called ‘Denver earthquakes’. They ranged up to M 5.3, caused
extensive damage in nearby towns, and as a result, use of the well
was discontinued in 1966. Despite the importance of induced
seismicity, only a few holistic reviews have been published (e.g.,
Nicholson, 1992; Gupta, 2002; Li et al., 2007). Compilations often
focus on selected mechanisms although there are notable exceptions (National Academy of Sciences, 2012).
Recently, the attention of regulators, agencies and the general
public has been drawn to induced seismicity linked to the hydraulic
fracturing of low-permeability sedimentary rocks such as ‘tight’
sandstones and shale, for oil and gas exploration and production.
Hydraulic fractures are stimulated to increase the surface area of
172
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
rock which is connected to the wellbore. This is achieved by
pumping water, proppant and chemicals during multiple fracture
stages, a process known as ‘fracking’ (e.g., King, 2010). After
pumping ceases the injected fluid is allowed to flowback to the
surface and can be disposed of by reinjection or processing.
Although hydraulic fracturing has been carried out since the 1940s,
the combination of multiple stages of fracturing in horizontal wells
in shale and tight sandstones and the widespread deployment of
this technology did not start until the 1990s (e.g., Curtis, 2002).
During or soon after hydraulic fracturing there may be an increase in fluid pressure along a fault plane, which, if critically
stressed, can be reactivated inducing seismicity (Fig. 1a and b). A
thorough review of the history of induced seismicity caused by a
variety of mechanisms including hydraulic fracturing is timely as it
places the magnitudes and frequency of hydraulic-fracturingtriggered seismicity into context. We introduce the theory behind
how earthquakes are induced, review the context of global induced
seismicity since 1929, and discuss the evidence that faults are being
reactivated as a result of hydraulic fracturing and the processes by
which this could be occurring.
1.1. Earthquakes
All rock masses that experience progressively changing stress
are potentially seismogenic, i.e., capable of producing earthquakes.
Progressive loading of stress by tectonic plate movements is the
primary geological earthquake-inducing process. It results in
intense deformation at the boundaries of plates, which are the most
active earthquake zones. Plates are not absolutely rigid and the
effect of their motions is transmitted into their interiors. There,
lower-level, intraplate deformation occurs. This is sometimes
localized in rift zones, e.g., the East African rift, and sometimes
distributed throughout broad regions, e.g., Britain, mainland
Europe, and the Basin and Range Province, western U.S.A. (Sykes
and Sbar, 1973).
Fluids play a critical role in triggering seismicity in many
different geological scenarios. Earthquake activity accompanies
volcanic activity, and liquid magma is involved in those cases, e.g.,
at Yellowstone, USA. Occasionally, large earthquakes are accompanied by significant changes in groundwater, e.g., changes in the
level of the water table. Usually, however, there is no direct evidence of fluid involvement. Nevertheless, fluids must lubricate fault
surfaces that slip in earthquakes because otherwise friction on the
fault plane would be too large to be overcome at the failure energy
levels observed. This conjecture is supported by the absence of a
large heat flow anomaly above the San Andreas fault zone, which
would inevitably be generated by the friction of dry rock surfaces
slipping past each other (Lachenbruch and Sass, 1980).
Artificially injecting fluids into the Earth’s crust induces earthquakes (e.g., Green et al., 2012). Fluid injection not only perturbs
stress (Fig. 1b) (Scholz, 1990) and creates new fractures, but it also
potentially introduces pressurised fluids into pre-existing fault
zones, causing slip to occur earlier than it would otherwise have
done naturally (Fig. 1a and b).
1.2. Earthquake sizes
Earthquakes range in magnitude from a maximum of w10 down
to arbitrarily small values. In the most sensitive microearthquake
monitoring experiments, the lower magnitude limit of earthquakes
that are reported is approximately M 3. Although traditional
earthquake magnitudes are a familiar measure to most people, they
are an empirical measure and no longer fit for modern purposes.
They have thus been superseded by seismic moment, a measure
that has physical meaning.
Figure 1. Induced seismicity caused by hydraulic fracturing. (a) Cartoon of a well
drilled vertically and then horizontally into fine-grained, low-permeability strata (dark
grey), which are offset by a normal fault (thick black line). Fluid, or a fluid pressure
pulse, can be transmitted into a nearby or intersecting, critically stressed fault (white
arrows). Compressive stresses s1, s2, and s3 act upon the fault. In this case s1 is
depicted as being vertical, s2 is horizontal (out of the page and not shown), and sN is
the normal stress acting on the fault plane. Failure occurs when the shear stress (s) is
higher than the sum of the shear strength (so) and frictional stress on the fault plane
(msN), where m is the coefficient of friction. (b) A Mohr diagram for the fault plane.
Mohr Circle 1 represents s1 and s3 for the critically stressed fault plane prior to hydraulic fracturing. It is therefore located close to the Mohr failure envelope. During
hydraulic fracturing, or during shut in of the well before flowback, the fluid pressure
within the fault zone could increase. This could occur due to transmission of a fluid
pressure wave or because hydraulic fracturing fluid or pore fluid enters the fault
increasing fluid pressure. This causes a reduction in the compressive stress, s1 and s3,
so the Mohr circle shifts to the left (red arrow, Mohr Circle 2), intersects the failure
envelope, shear failure occurs, and if this is over a significant length of the fault, there
is the potential for felt seismicity.
In the past, many magnitude scales were proposed to suit convenience in different situations, and several are still in widespread
use. Magnitudes are calculated from measurements made directly
from recorded seismograms, such as wave amplitudes or durations.
Magnitude formulae usually take into account the epicentral distance of the earthquake from the recording station, but they ignore
many other factors such as the hypocentral depth and the structure
of the Earth between the source and the recorder. As a result,
magnitude is not a measure of source physics, but of seismogram
characteristics. Different magnitudes are typically obtained by
analysing seismograms recorded at different seismic stations, or by
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
applying different magnitude scales to the same seismogram. Examples of different magnitude scales are the local magnitude scale
(ML e popularly known as the “Richter” magnitude scale), the
surface-wave magnitude scale (mS), and the duration magnitude
scale (MD). A further complication is that the type of instrument
used may be included in the magnitude scale definition. For
example, local magnitude is defined as applying to measurements
made from seismograms recorded on Wood-Anderson seismographs. These instruments are now obsolete, so the “Richter”
magnitudes commonly reported nowadays are not valid, for this
reason alone.
A rigorous way of estimating earthquake size is by using seismic
moment. This is the low-frequency scalar moment, M0, and it is a
measure of size based on the fundamental physics of the earthquake source. M0 varies by over 18 orders of magnitude, and thus it
is conventional to express it using an empirically derived logarithmic momentemagnitude relationship that yields numbers
similar to typical magnitudes. This formula is:
Mw ¼ 2=3logM0 10:7
where M0 is measured in dyne-cm (Hanks and Kanamori, 1979;
Kanamori, 1977). The moment magnitude (Mw) of an earthquake is
theoretically the same regardless of where the earthquake was
measured, the type of recording instrument, structure along the
wavepaths, or which stations are used. If earthquake size is an
important parameter it is crucial to use moment magnitude. Only
then can the sizes of earthquakes from different regions or time
periods be meaningfully compared.
If moments are unavailable, the next best thing is to use the
same type of magnitude, e.g., ML or MD. Estimates for the same
earthquake made using different magnitude scales may vary by
one, or even as much as two, magnitude units.
1.3. Earthquake numbers
Earthquakes result from brittle failure of the Earth’s crust. They
exhibit a log normal frequency distribution (Gutenberg and Richter,
1944). The frequency-magnitude slope of earthquake sequences is
usually approximately unity, meaning that for every reduction of
one magnitude unit, ten times as many earthquakes occur
(Gutenberg and Richter, 1944). The seismic rate for the world is
approximately one magnitude 9 earthquake per decade, one
magnitude 8 per year, 10 magnitude 7s, 100 magnitude 6s and so
on. The stress released by an earthquake is, however, approximately
30 times that released by an earthquake one magnitude unit
smaller. From this is easy to see why large earthquakes cannot be
prevented by inducing many smaller earthquakes. The fractal nature of earthquakes induced by human operations is not fundamentally different from that of natural earthquakes, and no case
has ever been reported where several tens of earthquakes of a given
magnitude have been induced without also producing events a
magnitude unit larger.
The number of earthquakes detected by a seismic network is
dependent on observational factors, e.g., the proximity of the
nearest seismic station and the quality of the installation. The closer
the station and the higher-quality the installation, the lower will be
the magnitude detection threshold and the larger the number of
earthquakes reported. Improvement of a network such that it
detected earthquakes one magnitude unit lower, e.g., by adding
additional stations close to the activated zone, would immediately
increase the numbers of earthquakes reported by an order of
magnitude. Thus, the number of earthquakes reported must be
taken in context. For example, a report that the number of earthquakes observed at one project was greater than the number
173
observed at another project is meaningless unless the monitoring
conditions were identical.
Earthquake magnitudes follow a power law distribution
described by the GutenbergeRichter relationship (Gutenberg and
Richter, 1944):
log N ¼ a bM;
where N is the number of earthquakes with magnitude greater than
or equal to magnitude M, and a and b are constants.
1.4. Induced earthquakes
A fault slips when the normal stress across a fault plane drops to
a sufficiently low level that the shear stress overcomes the static
friction on the fault surface. This is expressed by the Mohr diagram
(Fig. 1b). A fault can be brought to a critical state either by
increasing the shear stress, e.g., by plate motions or surface loading,
or by decreasing the normal stress that clamps the fault surfaces
together. The latter could be caused by processes such as stretching,
exhumation and erosion and by increasing the fluid pressure in the
fault zone.
Stress is perturbed, and earthquakes induced, by a number of
anthropogenic activities that change the loading state of the Earth’s
crust. These include the removal of subsurface volume by mining
the solid rock or the extraction of oil and gas. Mine-quakes are a
significant safety hazard and are common for example in the UK
and South Africa. Some mining operations, e.g., deep gold mines in
South Africa, are seismically monitored for safety reasons. Depleted
hydrocarbon reservoirs are often seismogenic, as reservoirs
collapse in response to the removal of pore fluids.
The injection of fluids into the subsurface is an increasingly
common activity. It is done to dispose of waste water or chemicals,
to flush hydrocarbons out of oil reservoirs, to fracture shale for gas
and oil extraction and to introduce water into geothermal reservoirs to create permeability and for circulation of hot fluid. Because
of the importance of managing induced earthquakes, the factors
that could affect the size of the largest earthquakes induced by
fluid-injection are of critical interest. Candidate operational parameters include the temperature and volume of the fluid injected,
and its type, phase, injection rate, pressure and depth below the
surface. The pre-existing stress- and fracture-state of area, i.e.,
whether the area contains large faults and is tectonically active,
may also be important. Fluid injections in stable continental interiors where differential stress levels are low and static, and there
is no history of seismicity, are likely be less seismogenic than injections in areas of active tectonics that already have a high natural
seismic rate and are thus critically stressed even before injection
commences. Sometimes, induced seismicity can reveal the presence of previously unknown faults. Correlations of various operational and seismic parameters have been measured in an attempt to
explore possible mitigating operational approaches.
2. History of induced seismicity
Since 1993 there have been seven generally accepted criteria
that must be met before fault reactivation is considered to have an
anthropogenic origin (Davis and Frohlich, 1993). These are:
1. Are these events the first known earthquakes of this character
in the region?
2. Is there a clear correlation between injection and seismicity?
3. Are epicentres near wells (within 5 km)?
4. Do some earthquakes occur at or near injection depths?
174
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
5. If not, are there known geologic structures that may channel
flow to sites of earthquakes?
6. Are changes in fluid pressures at well bottoms sufficient to
encourage seismicity?
7. Are changes in fluid pressures at hypocentral distances sufficient to encourage seismicity?
The literature on induced seismicity dates back to 1933 (Gupta,
1985; Rothé, 1970), well before the proposal by Davis and Frohlich
(1993) of these criteria. In this paper we compile all potential examples of induced seismicity, many of which did not use these
criteria. The total of 198 possible examples, come from 66 published papers and reports (Tables 1e3). Because we only use published examples, our database is not comprehensive. For instance,
we are aware of many unpublished examples of induced earthquakes associated with the mining industry in the UK, but it is
beyond the scope of this review paper to analyse unpublished
datasets. Lastly, in cases where a swarm of earthquakes thought to
be induced is reported, we have only recorded the magnitude of the
largest event.
We subdivide the seismicity by likely trigger mechanism into:
(a) mine subsidence, (b) oil and gas field depletion, (c) fluid injection for secondary oil recovery, (d) research-related projects, (e)
waste-water disposal, (f) solution mining, (g) Enhanced
Geothermal Systems (EGS) operations, (h) reservoir impoundment,
(i) groundwater extraction, and (j) hydraulic fracturing for recovery
of hydrocarbons from shale. We briefly review (a)e(i), and consider
(j) in more detail.
injection. Magnitudes of earthquakes range from M 1.9e5.1
(Table 2).
2.4. Research-related projects
Approximately 400 earthquakes occurred in association with
the German Continental Deep Drilling Program, which included a
borehole drilled to 9.1 km depth. They occurred at an average depth
of 8.8 km and are thought to have been induced by injection of
brine into a 70-m-thick open-hole section near the bottom of the
borehole. One conclusion of this work was that critically stressed,
permeable fault zones exist in the crust, even at great depth and
temperature (Zoback and Harjes, 1997). The event magnitudes
ranged from 2.8e3.1 (Table 2).
2.5. Waste-water disposal
Frohlich et al. (2011) concluded that the most likely cause of
an increase in seismicity in the Dallas Fort Worth area, USA,
with events of up to M 3.6, was probably the result of injecting
waste flowback water derived from the hydraulic fracturing of
shale for gas production. The depth and location of seismicity
were close to recent waste water injection activity. Magnitudes
for a range of different waste water injection activities are 2.0e
5.3 (Table 2).
2.6. Solution mining
2.1. Mine subsidence
Earthquakes induced by mine subsidence are some of the most
widely studied. They are often due to collapse of mine workings
(e.g., Bennett et al., 1996; Hubert et al., 2006; Li et al., 2007). These
earthquakes range from M 1.6 to 5.6 (Table 1). Often the only
damage they cause is to the mines and miners working in them, but
they have been known to damage the wider community (Li et al.,
2007).
2.2. Oil and gas field depletion
Earthquakes are caused by compaction of reservoirs as a result
of hydrocarbon extraction (e.g., Suckale, 2009). The flexure of the
overburden generates shear stresses that can induce slip along
weak shale strata (e.g., Hamilton et al., 1992). At the Lacq gas field
(southwest France) 1639 earthquakes were detected around the
field in the magnitude range M 1.9 to 6 (Bardainne et al., 2008). In
1976, 1984 there were M 7.0 events at Gazli, Uzbekistan. The area
around Gazli had been aseismic until these events. It is uncertain
that these events were induced, but several criteria indicate that
these are the largest examples of earthquakes induced by gas
extraction from a conventional gas field (Table 2).
2.3. Fluid injection for secondary oil recovery
Water is injected into oil fields to increase the percentage of oil
recovered and it can enter faults reducing normal stress and
allowing reactivation. Fluid injection for oil recovery also maintains
reservoir pressure and reduces or eliminates the compaction effects
if that pressure is communicated effectively throughout the reservoir. Davis and Pennington (1989) documented events with Mb e
4.3 to ML e 5 between 1974 and 1982 at the Cogdell oil field in West
Texas, USA. Cesca et al. (2011) document an example of a 4.3 M
event at the Ekofisk field (North Sea, UK), probably caused by water
Solution mining involves drilling wells into underground salt
deposits and injecting water into them to dissolve the salt. The
earliest reported induced earthquake is attributed to this operational technique (see Pechmann et al., 1995). That earthquake
occurred in Attica (New York, USA) in 1929, and had a magnitude of
M 5.3.
2.7. Enhanced Geothermal Systems (EGS) operations
The US$60 million Basel, Switzerland Enhanced Geothermal
Systems project involved creating a fracture network in hot rock,
through which fluid could be circulated to extract heat. Earthquakes with magnitudes up to ML 2.9 began to occur six days into
the main hydraulic fracturing operation (e.g., Häring et al., 2008).
This activity exceeded a pre-decided injection-cessation threshold,
but even though pumping was stopped, several more earthquakes
with magnitudes exceeding ML 3.0 occurred over the following two
months. In total, 13,500 earthquakes were recorded, nine of which
were of ML 2.5 or larger (Table 2).
2.8. Reservoir impoundment
Reservoir impoundment is a widely documented cause of
induced earthquakes, and a significant review was carried out in
1985 (Gupta, 1985). The weight of water loading on the surface
provides enough pressure to induce earthquakes (Carder, 1945).
Magnitudes of recorded cases range from 1.0 to 7.9 (Table 3). There
is dispute, however, as to whether the very large Wenchuan, China
M 7.9 earthquake resulted from filling the reservoir, or whether it
was a natural process (Ge et al., 2009 vs. Deng et al., 2010). It
resulted in w90,000 deaths and w100,000 injuries (Gahalaut and
Gahalaut, 2010). This issue is currently causing concern as the
Three Gorges Dam on the Yangtze river fills, and induced earthquakes as large as M 6.5 there have been forecast (Lixin et al., 2012).
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
175
Table 1
Earthquakes induced by mining operations.
Mine
Trona Mines
Newcastle
Ural Mts
Kentucky
New York
Welkom
Klerksdorp
Carletonville
Klerksdorp
Klerksdorp
Saar
Ruhr
Saarland
Utah
Liaoning
Copper Cliff North
Craig
Creighton
Fraser
Garson
Kidd Creek
Macassa
Nanshan
Gangdong
Shengli
Laohutai
Wulong
Taiji
Benxi Caitun
Mentougou
Chengzi
Fangshan
Jinhuagong
Baidong
Hauting
Taozhuang
Shunyuan
Sanhejian
Weixi
Zigong
Louguanshan
Chayuan
Yanshitai
Huachu
Sijiaotian
Liuzhi
Dizong
Bingshuijing
Dayong
Xifeng Nanshan
Shanjiaocun
Yueliangtian
Dahebian
Kaiyang
Meitanba
Enkou
Doulishan
Qiaotouhe
Shixiajiang
Xindong
Niumasi
Dahuatang
Qingshan
Qixingjiezhen
Xujiadong
Niwan
Shuikoushan
Yanguan
Huayazi
Location
Wyoming
Australia
Russia
South Africa
USA
USA
South Africa
South Africa
South Africa
South Africa
South Africa
Germany
Germany
UK
Germany
USA
China
Ontario, Canada
Ontario, Canada
Ontario, Canada
Ontario, Canada
Ontario, Canada
Ontario, Canada
Ontario, Canada
China
China
China
China
China
China
China
China
China
China
P China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
China
Resource
Trona
Coal
Gold
Gold
Gold
Gold
Gold
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Salt
Salt
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Phosphorus
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Coal
Pyrite
Coal
Uranium
Gypsum
LeadeZinc
Coal
Coal
Largest Earthquake
Reference
Date
Magnitude
Magnitude type
reported
1995
1989
1995
1994
1995
1994
1976
1977
1992
2004
2005
2008
2007
1986
2008
2000
1977
2008
2007
2006
2008
2008
2009
2008
2001
5.1
5.6
4.4
5.6
4
3.6
5.2
5.2
4.7
4.9
5.3
4
3.3
2.8
4
2.2
4.3
3.8
2.2
4.1
2.4
3.3
3.8
3.1
3.7
2.3
2.8
2.5
3.8
4.3
2.8
4.2
3.4
3
2.1
2.7
3.3
3.6
3.6
3.4
4.2
4.6
4.3
4.3
4.3
4.1
2.7
3.6
2.7
3.6
3.1
3.1
3.1
3.1
2.8
2.2
2.8
2.9
2.5
2.2
1.6
3
3.2
2.7
2.6
3.1
3.4
2.8
2
2.5
2.8
ML
Mo
M
M
M
M
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
M
Mo
Mo
Mo
Mo
Mo
Mo
Mo
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
1978
1981
2004
1977
2004
1994
1997
1983
1982
2002
2003
1979
1985
1994
1987
1987
1982
1985
1991
1985
1991
1991
1991
1997
1997
1985
1990
1991
1976
1985
1974
1991
1994
1997
1997
1996
1996
1998
2003
1988
1973
1
2
2
2
2
2
3
3
3
3
3
4
4
5
6
7
8
9
9
9
9
9
9
9
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
(continued on next page)
176
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
Table 1 (continued )
Mine
Huaibashi
Wacang
Western Deep Levels East
Wappingers Falls
Reading
Belchatow
Location
Resource
China
China
South Africa
New York, USA
Pennsylvania, USA
Poland
Largest Earthquake
Coal
Coal
Gold
Coal
Reference
Date
Magnitude
Magnitude type
reported
1972
1971
1996
1974
1994
1980
3.6
3.8
4
3.3
4.3
4.6
ML
ML
ML
M
M
M
10
10
11
12
12
12
1. Pechmann et al. (1995); 2. Bennett et al. (1996); 3. Hubert et al. (2006); 4. Bischoff et al. (2009); 5. Redmayne (1988); 6. Fritschen (2009); 7. Arabasz et al. (2005); 8. Zhong
et al. (1997); 9. Vallejos and McKinnon (2011); 10. Li et al. (2007); 11. Amidzic et al. (1999); 12. Majer (2011). Gaps in this and subsequent tables are where information was not
specified in the published source.
Table 2
Earthquakes induced by waste injection, oil and gas field depletion, pressure support for oil and gas fields, salt mining, hydraulic fracturing for shale gas exploitation and
geothermal exploitation.
Project
Catoosa
East Durant
El Reno
Flashing Field
Imogene Field
War-Wink
Fashing
Lacq
Gazli
Eleveld
Snipe Lake
Strachan
Sleepy Hollow
Love Co
Gobles Field
Cogdell Field
Dollarhide
Dora Roberts
Kermit Field
Keystone
Monahans
Panhandle
Ward-Estes
Ward-South
Apollo Hendrick Field
Montebello
Orcutt Field
Wilmington
Richland
Romashkinskoye
Renqiu
Xingtai
Hunt Field
East Texas
Ekofisk
Barsa-Gelmes-Wishka
Akmaar
Cleburne
Groningen Field
Roswinkel
Rotenburg
Elsenbech
Upper Silesian
Rangely
Matsushiro
KTB
Attica
Dale
Cleveland
Dallas-Fort Worth
Ashtubla
Perry
Location
Oklahoma, USA
Oklahoma, USA
Oklahoma, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
France
Uzbekistan
Netherlands
Alberta, Canada
Alberta, Canada
Nebraska, USA
Oklahoma, USA
Ontario, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Texas, USA
Iran
California, USA
California, USA
California, USA
Illinois, USA
Russia
China
China
Mississippi, USA
Texas, USA
North Sea, UK
Turkmenistan
Netherlands
Texas, USA
Netherlands
Netherlands
Germany
Germany
Germany
Colorado, USA
Japan
Germany
New York, USA
New York, USA
Ohio, USA
Texas, USA
Ohio, USA
Ohio, USA
Resource
Gas
Gas
Gas
Gas
Gas
Gas
Gas
Gas
Gas
Gas
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Oil
Other
Other
Research
Research
Research
Salt
Salt
Salt
Shale Gas
Shale Gas
Shale Gas
Activity
Largest Earthquake
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
Secondary
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
recovery
Production
Production
Production
Production
Production
Production
Production
Secondary recovery
Secondary recovery
Secondary recovery
Secondary recovery
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Withdrawal
Research
Research
Research
Solution mining
Solution mining
Solution mining
Water disposal
Water disposal
Water disposal
Ref
Year
Magnitude
Magnitude type
reported
1956
1968
4.7
3.5
5.2
3.4
3.9
3
4.3
4.2
7.3
2.7
5.1
4
2.9
1.9
2.8
5.3
3.5
3
4
3.5
3
3.4
3.5
3
2
6
5.9
3.5
5.1
4.9
4
4.5
6
3.6
4.3
4.2
6
3.5
2.8
3.2
3.4
4.5
5.8
4.5
3.1
2.8
2.8
5.2
1
3
3.3
3.6
2.7
ML
ML
ML
ML
ML
ML
Mb
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
M
ML
ML
ML
ML
ML
Mo
ML
ML
ML
ML
Mo
ML
M
M
M
M
M
M
M
ML
M
M
ML
ML
ML
M
ML
ML
1984
1993
1978
1976
1991
1970
1974
1979
1989
1987
1991
1991
1987
1981
1978
1957
2001
1970
1929
1971
2009
1987
1
1
1
1
1
1
2
3
4
5
1
1
1
1
1
1,6
1
1
1
1
1
1
1
1
7
5
1
1
1
1
8
9
9
1
1
10
11
12
13
14
14
13
13
13
1
15,16
17
1
1
1
18
1
1
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
177
Table 2 (continued )
Project
Lancashire
Etsho and Kiwigana,
Eola Field
Cold Lake
El Dorado
Denver
Lake Charles
Paradox Valley
Geysers
Rangely
Basel
Cooper Basin
Soultz
Berlin
Reykjanes
Larderello
Fenton Hill
Bad Urach
Cesano
Krafla
Landau
Latera
German Continental
Deep Drilling Program
Monte Amiata
Mutnovsky
Ogachi
Rosemanowes
Torre Alfina
Unterhaching
Location
Resource
UK
Canada
Oklahoma
Alberta, Canada
Arizona, USA
Colorado, USA
Los Angeles, USA
Colorado, USA
California, USA
Colorado, USA
Switzerland
Australia
France
El Salvador
Iceland
Italy
New Mexico, USA
Germany
Italy
Iceland
Germany
Italy
Germany
Shale Gas
Shale Gas
Shale Gas
Waste
Waste
Waste
Waste
Waste
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Italy
Russia
Japan
UK
Italy
Germany
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Geothermal
Activity
Largest Earthquake
Hydraulic fracturing
Hydraulic fracturing
Hydraulic fracturing
Disposal
Disposal
Disposal
Disposal
Disposal
Ref
Year
Magnitude
Magnitude type
reported
2011
2009e2011
2011
2.3
3.8
2.8
2
3
5.3
3.8
4.3
4.6
3.4
3.4
3.7
2.7
4.4
4
3.2
1
1.8
2
2
2.7
3
1.2
Mo
ML
M
ML
ML
ML
ML
M
ML
ML
ML
Mo
ML
Mo
ML
ML
M
Mo
Mo
Mo
Mo
Mo
Mo
19
35
22
1
1,16
1,20
1
21
23
24
25
26
27
28
29
30
31
32
32
32
32
32
32
3.5
2
2
2
3
2.4
Mo
M
M
Mo
Mo
Mo
32
33
34
32
32
32
1967
1982
1964
2006
2003
2003
2008
1978
1971
1. Nicholson (1992); 2. Davis et al. (1995); 3. Lahaie et al. (1998); 4. Mirzoev et al. (2009); 5. Roest and Kuilman (1994); 5. Jalali et al. (2008); 6. Davis and Pennington (1989); 7.
Doser et al. (1992); 8. Galybin et al. (1998); 9. Genmo et al. (1995); 10. Ottermöller (2005); 11. Kouznetsov et al. (1994); 12. Giardini (2011); 13. Howe et al. (2010); 14. Van Eck
et al. (2006); 15. Ohtake (1974); 16. Nicholson and Wesson (1990); 17. Zoback and Harjes (1997); 18. Frohlich et al. (2011); 19. de Pater and Baisch (2011); 20. Van Poollen and
Hoover (1970); 21. Ake et al. (2005); 22. Holland (2011); 23. Julian et al. (1996); 24. Gibbs et al. (1973); 25. Häring et al. (2008); 26. Baisch et al. (2006); 27. Bourouis and Pascal
(2007); 28. Majer et al. (2007); 29. Keiding et al. (2010); 30. Batini et al. (1985); 31. Phillips et al. (2002); 32. Evans et al. (2012); 33. Kugaenko et al. (2005); 34. Kaieda et al.
(2010). 35. BC Oil and Gas Commission (2012). The 2011 Mw 5.7 earthquake sequence published by Keranen et al. (in press) is not included in the table and represents the
largest earthquake triggered by waste water injection to be published to date.
Table 3
Earthquakes induced by surface reservoir construction and impoundment.
Reservoir
Marathon
Oued Fodda
Hoover
Shasta
Clark Hill
Eucumbene
Kariba
Kerr
Camerillas
Canellas
Kurobe
Koyna
Monteynard
Contra
Aswan Dam
Benmore
Kremesta
Piastra
Grancarevo
Oroville
Blowering
Vouglans
Kastraki
Hendrik Verwoerd
Kamafusa
Schlegeis
Location
Greece
Algeria
Nevada, USA
California, USA
Indiana, USA
Australia
Zambia
North Carolina, USA
Spain
Spain
Japan
India
France
Switzerland
Egypt
New Zealand
Greece
Italy
Serbia
Washington, USA
Australia
France
Greece
South Africa
Japan
Austria
Year of
impoundment
Largest Earthquake
Date
Magnitude
Magnitude type
reported
References
1929
1932
1935
1944
1952
1957
1958
1958
1960
1960
1960
1962
1962
1963
1964
1964
1965
1965
1967
1967
1968
1968
1969
1970
1970
1970
1938
1933
1939
1944
1974
1959
1963
1971
1964
1962
1961
1967
1963
1965
1981
1966
1966
1966
1967
1975
1973
1971
1969
1971
1970
1971
5.7
3
5
3
4.3
5
6.2
4.9
4.1
4.7
4.9
6.3
4.9
3
5.5
5
6.3
4.4
3
5.7
3.5
4.4
4.6
2
3
2
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
1
1,
1,
1
1
1
1,
1
1
1,
1
1,
1,
1
1
1
1,
1
1
1
1
1
1
1
1
1
2
2
3
2
2
2
2, 4
(continued on next page)
178
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
Table 3 (continued )
Reservoir
Jocassee
Talbingo
Nurek
Emmonson
Keban
Volta Grande
Idukki
Manicouagan
Itezhitezhi
Monticello
Srinagarind
Toktogul
Zipingpu
Location
South Carolina, USA
Australia
Tajikistan
Switzerland
Turkey
Brazil
India
Quebec Canada
Zambia
California, USA
Thailand
Kyrgyzstan
China
Year of
impoundment
Largest Earthquake
Date
Magnitude
Magnitude type
reported
1971
1971
1972
1973
1973
1973
1975
1975
1976
1977
1977
1977
2006
1975
1973
1972
1973
1973
1974
1977
1975
1978
1979
1983
3.2
3.5
4.6
3
3.5
4
3.5
4.1
4
2.8
5.9
2.5
7.9
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
ML
2008
References
1,
1
1,
1
1
1
1
1
1
1
1,
1
1,
5, 6
5
7
8, 9, 10, 11
1: Gupta (1985); 2: Rothé (1970); 3: Gough and Gough (1970); 4: Stein et al. (1982); 5: Keith et al. (1982); 6: Zoback and Hickman (1982); 7: Chung and Liu (1992); 8: Gahalaut
and Gahalaut (2010); 9: Lei et al. (2008); 10: Klose (2007); 11: Ge et al. (2009).
2.9. Groundwater extraction
González et al. (2012), suggest that stress induced by major
groundwater extraction probably triggered the Mw 5.1 earthquake
that occurred in Lorca, southeast Spain, 11th May 2011. This
earthquake caused nine fatalities and considerable devastation for
such a moderate event, principally because the focus was shallow at
about 2e4 km depth.
Faults in the crust are in a state of frictional equilibrium under
complex systems of stress, partly tectonic in this case through the
interaction between the North African and Southern European
areas, and also because of the weight of the overburden itself.
Isostatic unloading and the associated elastic response of the crust
and lithosphere is well known as a cause of seismicity, and much of
NW Scotland’s historic seismicity is associated with glacial
unloading from the last ice sheet ca. 10,000 years ago. The Betic
Cordillera is one of the most seismically active areas in the Iberian
Peninsula and it is not surprising that the removal of 250 m of
groundwater since 1960, a significant mass change over a short
period of time, together with the many centimetres of subsidence
caused by the consequential compaction, could provide the minor
stress perturbation necessary to bring local faults to failure.
Figure 2 shows a graph of earthquake magnitude vs. frequency
where magnitudes range from 1.0 to 7.9. This graph only documents examples of induced seismicity which have been published,
and the hundreds of anecdotal mining-induced earthquakes with
M > 1 in the UK, for example, are not included. Figure 2 shows that
the most commonly reported induced earthquakes are M 3e4. The
paucity of events of smaller magnitudes reflects lack of detection
and reporting. Mining, oil- and gas-field depletion, reservoir
impoundment, EGS wells, and waste water injection are the most
frequently reported causes of induced seismicity.
out in multiple stages with fluids with known volumes and compositions (e.g., Bell and Brannon, 2011). Approximately 10e40% of
the hydraulic fracturing fluid used flows back after stimulation. In
some cases faulted areas of the reservoir are specifically targeted
because there may be pre-existing fault and fracture permeability.
There are many good examples of hydraulic fracturing that has
caused fault or fracture reactivation (e.g., Warpinski et al., 1998;
Wolhart et al., 2005; Vulgamore et al., 2007; Maxwell et al., 2008;
Cipolla et al., 2012). The seismicity is generally very low magnitude
(<M 0) and typically not recorded above the noise level by traditional surface seismometer networks. Monitoring of fracture
growth and fault reactivation is thus done using downhole
geophone strings that are deployed within a few hundred metres of
the hydraulic fracturing. Only by deploying sensors so close to the
seismicity can data be collected of sufficient high quality that locations and other processing results can be calculated for these tiny
events. Alternatively, massive surface arrays comprising hundreds
3. Hydraulic fracturing
3.1. Operations
Exploration wells targeting low permeability sedimentary reservoirs, particularly in new exploration settings, are commonly
drilled vertically and then hydraulically fractured. Production wells
are typically deviated so that the borehole is strata-parallel through
the reservoir (Fig. 1a). The production casing is perforated and
hydraulic fractures are stimulated by injecting saline water with
chemical additives. ‘Proppant’e sand or synthetic ceramic spheres
e is used to keep the fractures open (e.g. King, 2010). Hydraulic
fracture stimulation from a horizontal borehole is usually carried
Figure 2. Frequency vs. magnitude for 198 published examples of induced seismicity
(see Tables 1e3). The many examples of induced seismicity that are not published are
not included on this graph.
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
179
Figure 3. Moment magnitude vs. distance from seismic stations for induced hydraulic fracturing operations in a number of wells in the Jonah Field (Wyoming, USA e after Wolhart
et al., 2005). The clustering of events with larger magnitudes is indicative of fault reactivation due to pumping of hydraulic fracturing fluid. Inset e location map.
or thousands of seismometers are deployed, so the signal-to-noise
ratio can be enhanced by stacking the seismograms (Grechka, 2010;
Gei et al., 2011).
Most of the criteria proposed by Davis and Frohlich (1993) for
induced seismicity are fulfilled for seismicity recorded during
hydraulic fracturing operations. We review the data here, and use it
to understand the geological processes by which fault reactivation
occurs during and after the hydraulic fracturing operations.
3.2. Earthquake magnitudes
Fault reactivation can cause earthquakes with magnitudes
larger than expected for fracture propagation. Wolhart et al.
(2005) demonstrated this in the Jonah Field in Wyoming, USA
(Fig. 3). Hydraulic fracturing of the Late Cretaceous Lance Formation was carried out in a number of wells, with 9e11 hydraulic
fracturing stages, using an energized borate cross-linked gel
(Wolhart et al., 2005; Downie et al., 2010). The East 1 well was
used for seismic measurements and the East 3 well was used for
the hydraulic fracturing (Fig. 3). A graph of moment magnitude vs.
distance is commonly used to identify seismicity that is anomalously large, and that clusters at specific distances from the
monitoring well. Both characteristics indicate reactivation of a
discrete fault (Fig. 3).
Increases in the magnitude of the microearthquakes with time
following the onset of pumping are indicative of fault reactivation.
Figure 4. Detecting fault reactivation by changes in b-value. In this example a thrust
fault was reactivated after the injection period had ended and this is marked by a
change in the b-value from 2 to 1 (after Maxwell et al., 2009).
Figure 5. Pumped volume, flowback volume and moment magnitude for several microearthquakes vs. time for the Preese Hall well, drilled in 2011 in Lancashire, UK (de
Pater and Baisch, 2011).
Figure 6. Microearthquakes from the Jonah Field (Wyoming, USA, location Fig. 3
inset). Blue dots: microearthquakes caused by the propagation of hydraulic fractures
in East 3 well. This probably allowed fluid movement into a fault, reducing normal
stress, and reactivating it (yellow and green dots). After Wolhart et al. (2005).
180
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
These have been reported to have been accompanied by a sharp
reduction in b-value, calculated for a moving subset of events over
the time that pumping took place (Maxwell et al., 2009 e Fig. 4). For
example, in the case of the study of Maxwell et al. (2009), a thrust
fault was penetrated by the treatment well. Sandstones offset by
the fault were hydraulically fractured with a ca. 80-min-long injection. After pumping ceased, the earthquakes would be expected
to reduce in size, but in this case they became larger. The b-value
dropped from w2 to w1, and this was interpreted as indicating
fault reactivation (Maxwell et al., 2009; Downie et al., 2010 e
Fig. 4). Until recently such analyses were carried out after hydraulic
fracturing was completed. However, Kratz et al. (2012) report results from the hydraulic fracturing of four horizontal wells in
Montague county in Texas, in the lower Barnett shale, and propose
that the b-values are evidence for early fault movement during and
after the hydraulic fracturing.
Precursory microseismicity was not recorded in the Preese
Hall well, in Lancashire, UK in 2011, where several events up to
M 2.3 have been ascribed to fault reactivation (Fig. 5, Green
et al., 2012). At the Preese Hall 1 well, 55 events were recorded. That the hydraulic fracturing caused fault reactivation was
proposed on the basis of the unusually high magnitude and the
close temporal coincidence with hydraulic fracturing stages
(Fig. 5).
3.3. Spatial and temporal characteristics
Spatial clustering of the larger earthquakes can occur (Wolhart
et al., 2005 e Fig. 3). Earthquakes induced at the Jonah Field,
Wyoming, showed a spatial distribution that suggested new hydraulic fractures fed hydraulic fracturing fluid into a fault which
consequently reactivated (Maxwell et al., 2008 e Fig. 6). The fault is
approximately 200 m from the injection well.
Clustering can be temporal as well as spatial. Wessels et al.
(2011) showed that for three hydraulic fracturing operations in a
24 h period there were significant increases in the normalised
seismic energy emitted, and this was interpreted as discrete episodes of fault movement. Hulsey et al. (2010) describe induced
strike-slip and reverse faulting in the Marcellus shale, USA,
resulting from hydraulic fracturing, and characterized by short
bursts of earthquakes.
Mapping hydraulic fractures in the Montney Formation, Canada,
using seismicity, shows that hydraulic fractures can terminate at
faults which have been mapped using 3D seismic reflection data
(Maxwell et al., 2011) (Fig. 7). The edge detection map (often used
Figure 7. (a) Three wells, A, B, and C, drilled into the early Triassic upper Montney
Formation in northeast British Columbia. The orange dashed line bounds the microseismicity in the northeast. (b) Edge attribute (see Brown, 2010) for a reflection in a 3D
dataset over the upper Montney Formation showing NWeSE orientated faults. After
Maxwell et al. (2011).
Figure 8. Map of microearthquakes induced by multiple stages of hydraulic fracturing
in the Barnett shale (after Kratz et al., 2012). Blue lines e boreholes, blue dots e
earthquakes with strike-slip motion, red dots e earthquakes with dip slip motion.
Changes in the sense of shear on failure planes are thought to indicate a change from
the stimulation of new hydraulic fractures (red dots) to fault reactivation (blue dots).
Yellow-dashed lines mark interpreted extents of damage zones. This case study
probably represents an example of the direct injection of fracturing fluid into a fault
zone.
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
to identify faults in 3D seismic datasets) reveals a number of faults
that trend NWeSE. The largest earthquakes located are close to a
NWeSE trending fault, consistent with the interpretation that it
was reactivated.
As well as injection into faults via new fractures, injection
directly into faults has been recorded in the Barnett Shale (USA)
(Kratz et al. (2012) (Fig. 8). The faults are strike-slip, whereas the
fractures are normal. Thus, the changes in the sense of shear as well
as the spatial clustering are diagnostic of fault reactivation rather
than the stimulation of new fractures.
There is a growing body of research that models the process of
fluid-injection-induced seismicity (e.g., Shapiro and Dinske, 2009).
For example Rozhko (2010) focus on the spatial and temporal
development of the microseismicity that occurs due to hydraulic
fracturing and proposes that it can modelled on the basis of linear
pressure diffusion in the fluid, coupled to deformation of a linear
poroelastic medium. The microseismicity is considered to be
caused by changes in the Coulomb yielding stress along a pressure
181
diffusion front, caused by seepage forces (Rozhko, 2010). Geiser
et al. (2012) propose that they can image extensive pre-existing
fractures stimulated by these processes using a passive seismic
method coined ‘tomographic fracture imaging’ caused by transmission of a fluid pressure pulse. The following year Lacazette and
Geiser (2013) clarified that, it’s not only a fluid pressure pulse but
also poroelastic coupling of the stress in the rock to pore and
fracture fluids could cause the stress changes without any fluid flow
that stimulates fractures 100s of metres from the place where hydraulic fractures were initiated.
3.4. Long-period and long-duration events
Because of the high pressure of the hydraulic fracturing fluid,
faults poorly orientated relative to the stress field may slip, but the
slip may be slow and not generate conventional high-frequency
microearthquakes (Das and Zoback, 2011). Das and Zoback (2011)
studied 10e80 Hz, long-period, long-duration (LPLD) events
Figure 9. Long-period, long-duration (LPLD) seismicity recorded during a multi-well, multi-stage hydraulic fracturing operation in the Barnett Shale in Texas (after Das and Zoback,
2011). (a) Geometry and arrangement of wells AeE with reported seismicity. (b) Axial spectrogram of stage 7 of wells A and B revealing numerous LPLD events. (c) Examples of LPLD
events observed at frequencies below 100 Hz taken from (b). Blue arrows point to the LPLD seismic events.
182
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
Barnett, USA (1)
Marcellus, USA (1)
Woodford, USA (1)
Haynesville, USA (1)
Eagle Ford, USA (1)
Muskwa/Evie, USA (1)
Lancashire, UK (2)
Eola Field*, USA (3)
Etsho and Kiwiganaola**, Canada (4)
Moment Magnitude/Richter Scale**/
Duration Magnitude*
-3
-2
-1
0
1
2
3
4
Figure 10. Comparison of reported earthquake moment magnitudes recorded in the
USA, Canada and UK. (1) from Warpinski et al. (2012); (2) from de Pater and Baisch
(2011); (3) from Holland (2011); (4) from the BC Oil and Gas Commission (2012).
hydraulic fracturing. The field is characterised by a series of WNWe
ESE striking faults. 43 earthquakes were located there in 2011 with
magnitudes up to 2.8. Hydraulic fracturing was carried out in a
number of stages and earthquakes onset 13 h after operations
began (Holland, 2011).
A total of 216 earthquakes occurred 2009e2011 at the Etsho and
Kiwigana fields in Horn River, Canada and 19 were between ML 2
and 3 (Fig. 11). The largest event had a magnitude of ML 3.8, it
occurred in May 2011, and it was felt. There was a clear temporal
relationship between pumping and the seismicity, with earthquakes starting several hours after the beginning of pumping (BC
Oil and Gas Commission, 2012).
4. Process model
which have similar characteristics to tectonic tremors observed in
subduction zones and strike-slip plate boundaries. The maximum
number of LPLD events were detected in the hydraulic fracturing
stages with the highest pumping pressure and the highest natural
fracture density (Fig. 9). The events were interpreted as slow shear
slip on pre-existing natural fractures as a result of the high fluid
pressure. The faults that moved were poorly orientated relative to
the stress field.
3.5. Nuisance seismicity
The majority of data from the USA show that when fault reactivation occurs the earthquake magnitudes tend to be very low, and
do not exceed w M 1 (Fig. 10). There are three known exceptions to
this, Etsho and Kiwigana, Canada in 2009, 2010 and 2011 (BC Oil
and Gas Commission, 2012), the Eola Field, Oklahoma, USA in
2011 (Holland, 2011) and Lancashire, UK in 2011 (de Pater and
Baisch, 2011). In 2011 a felt earthquake of magnitude M 2.3
occurred in Lancashire, UK, as a result of hydraulic fracturing of the
Preese Hall well (Fig. 5). The seismicity at the Eola Field, southern
Garvin County, Oklahoma, has been tentatively attributed to
A number of conclusions can be drawn from these examples.
Firstly there is evidence that faults can be connected to the
injection well via hydraulic fractures (Fig. 6) as well as direct
injection into faults intersecting the treatment wells (Fig. 8).
Even where faults are intersected by the treatment wells, there
is often a time lag of several hours between the start of pumping
and fault reactivation. At the Preese Hall 1 well (Lancashire, UK),
there was a delay of 10 h between cessation of pumping and the
M 2.3 earthquake (de Pater and Baisch, 2011). The same observation was made by Maxwell et al. (2009) who observed a delay
of approximately 80 min from the onset of pumping and evidence for fault reactivation in gas wells in Western Canada.
Examples of felt seismicity documented in the Horn River,
Canada occurred several hours after the start of pumping (BC Oil
and Gas Commission, 2012). The delay between pumping and
the reactivation of some faults (e.g., Maxwell et al., 2009) may in
part be because the fault into which fluid is injected has
inherent storage and transmissibility characteristics, or due to
the time required for the transmission of fluid pressure by
pressure diffusion and due to poroelasticity (Lacazette and
Geiser, 2013).
Figure 11. Range of magnitudes for the cases of felt seismicity including only magnitudes > M 1. Etsho and Kiwiganaola were reported on the ML scale (magnitudes from Fig. 9 of BC
Oil and Gas Commission, 2012), Preese Hall-1 events were recorded as moment magnitudes (de Pater and Baisch, 2011) and Eola Field, Oklahoma, USA events as duration
magnitude.
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
183
Acknowledgements
We thank Durham and Keele Universities for giving the authors
time to carry out this research. We thank Peter Geiser for reviewing
the paper.
References
Figure 12. Cartoon of low-permeability reservoir with an intersecting fault and potential mechanisms for the transmission of a pore fluid pressure pulse or fluid into a
fault to cause reactivation. 1 e Direct connection and injection into the fault (e.g.,
Hulsey et al., 2010); 2 e fluid flow through the stimulated hydraulic fractures into the
fault (e.g., Wolhart et al., 2005); 3 e fluid flow through the existing fractures; 4 e fluid
flow through permeable strata and along bedding planes.
In summary there are several mechanisms by which faults are
reactivated due to hydraulic fracturing to cause felt seismicity.
Fracturing fluid or displaced pore fluid could enter the fault, a fluid
pressure pulse could be transmitted to the fault and due to
poroelasticity, deformation or ‘inflation’ of the rock due to injection could increase fluid pressure in the fault or in the fractures
connected to the fault (e.g. Lacazette and Geiser, 2013). The
following pathways for fluid or a fluid pressure pulse are proposed: (a) directly from the wellbore; (b) through new, stimulated
hydraulic fractures; (c) through pre-existing fractures and minor
faults; or (d) through the pore network of permeable beds or
along bedding planes (Fig. 12). The reactivated fault could be
intersected by the wellbore or it could be 10s to 100s of metres
from it.
5. Conclusions
Of the 198 possible examples of induced seismicity reported in
the literature, magnitudes range up to M 7.9. Hydraulic fracturing of
sedimentary rocks, for recovery of gas from shale, usually generates
very small magnitude earthquakes only, compared to processes
such as reservoir impoundment, conventional oil and gas field
depletion, water injection for geothermal energy recovery, and
waste water injections. We have proposed four primary mechanisms for fault reactivation by hydraulic fracturing. Although there
are approaches for mitigating the risks (e.g., Brodylo et al., 2011;
Green et al., 2012) and faults can often be imaged by seismic
reflection data, and avoided, it cannot be ruled out that reactivation
of pre-existing faults could induce felt seismicity. It should be
noted, however, that after hundreds of thousands of fracturing
operations, only three examples of felt seismicity have been
documented. The likelihood of inducing felt seismicity by hydraulic
fracturing is thus extremely small but cannot be ruled out.
Ake, J., Mahrer, K., O’Connell, D., Block, L., 2005. Deep-injection and closely induced
seismicity at Paradox Valley, Colorado. Bulletin of the Seismological Society of
America 95, 664e683.
Amidzic, D., Murphy, S.K., Van Aswegen, G., 1999. Case Study of a Large Seismic
Event at a South African Gold Mine, pp. 1033e1038.
Arabasz, W.J., Nava, S.J., McCarter, M.K., Pankow, K.L., Pechmann, J.C., Ake, J.,
McGarr, A.M., 2005. Coal-mining seismicity and ground-shaking hazard: a case
study in the Trail Mountain Area, Emery County, Utah. Bulletin of the Seismological Society of America 95, 18e30.
Baisch, S., Weidler, R., Voros, R., Wyborn, D., de Graaf, L., 2006. Induced seismicity
during the stimulation of a geothermal HFR reservoir in the Cooper Basin,
Australia. Bulletin of the Seismological Society of America 96, 2242e2256.
Bardainne, T., Dubos-Sallée, N., Sénéchal, G., Gaillot, P., Perroud, H., 2008. Analysis of
the induced seismicity of the Lacq gas field (Southwestern France) and model of
deformation. Geophysical Journal International 172, 1151e1162.
Batini, F., Console, R., Luongo, G., 1985. Seismological study of Larderello d Travale
geothermal area. Geothermics 14, 255e272.
BC Oil and Gas Commission, 2012. Investigation of Observed Seismicity in the Horn
River Basin. <http://www.bcogc.ca/publications/reports.aspx>.
Bell, C.E., Brannon, H.D., 2011. Redesigning Fracturing Fluids for Improving Reliability
and Well Performance in Horizontal Tight Shale Applications. SPE 140107.
Bennett, T.J., Marshall, M.E., Mclaughlin, K.L., Barker, B.W., Murphy, J.R., 1996.
Seismic characteristics and mechanisms of rockbursts. In: Proceedings of the
18th Annual Seismic Research Symposium on Monitoring a Comprehensive Test
Ban Treaty Phillips Laboratory, 153, pp. 901e907.
Bischoff, M., Cete, A., Fritschen, R., Meier, T., 2009. Coal mining induced seismicity in
the Ruhr Area, Germany. Pure and Applied Geophysics 167, 63e75.
Bourouis, S., Pascal, B., 2007. Evidence for coupled seismic and aseismic fault slip
during water injection in the geothermal site of Soultz (France), and implications
for seismogenic transients. Geophysical Journal International 169, 723e732.
Brodylo, J., Chatellier, J.-Y., Matton, G., Rheault, M., 2011. The Stability of Fault Systems in the South Shore of St Lawrence Lowlands of Québec e Implications for
Shale Gas Development. SPE 149307.
Brown, A., 2010. Interpretation of Three-dimensional Seismic Data. Tulsa, seventh
ed., p. 560
Carder, D.S., 1945. Seismic investigations in the Boulder Dam area, 1940e1944, and
the influence of reservoir loading on local earthquake activity. Bulletin of the
Seismological Society of America 35 (4), 175e192.
Cesca, S., Dahm, T., Juretzek, C., Kühn, D., 2011. Rupture process of the 2001 May 7
Mw 4.3 Ekofisk induced earthquake. Geophysical Journal International 187,
407e413.
Chung, W.Y., Liu, C., 1992. The Reservoir-associated Earthquakes of April 1983 in
Western Thailand: source modeling and implications for induced seismicity.
Pure and Applied Geophysics 138, 17e41.
Cipolla, C., Maxwell, S., Mack, M., 2012. Engineering Guide to the Application of
Microseismic Interpretations. SPE 152165.
Curtis, J.B., 2002. Fractured shale-gas systems. American Association of Petroleum
Geologists Bulletin 86, 1921e1938.
Das, I., Zoback, M.D., 2011. Long Period, Long Duration Seismic Events During Hydraulic Fracture Stimulation of a Shale Gas Reservoir. SEG, San Antonio.
Davis, S.D., Frohlich, C., 1993. Did (or will) fluid injection cause earthquakes?:
criteria for a rational assessment. Seismological Research Letters 64, 207e224.
Davis, S.D., Pennington, W.D., 1989. Induced seismic deformation in the Cogdell
oil field of West Texas. Bulletin of the Seismological Society of America 79,
1477e1495.
Davis, S.D., Nyffenegger, P.A., Frohlich, C., 1995. The 9 April 1993 earthquake in
south-central Texas: was it induced by fluid withdrawal? Bulletin of the Seismological Society of America 85, 1888e1895.
de Pater, C.J., Baisch, S., 2011. Geomechanical Study of Bowland Shale Seismicity.
www.cuadrilla.com.
Deng, K., Zhou, S., Wang, R., Robinson, R., Zhao, C., Cheng, W., 2010. Evidence that
the 2008 Mw 7.9 Wenchuan earthquake could not have been induced by the
Zipingpu reservoir. Bulletin of the Seismological Society of America 100 (5B),
2805e2814.
Doser, D.I., Baker, M.R., Luo, M., Marroquin, P., Ballesteros, L., Kingwell, J., Diaz, H.L.,
Kaip, G., 1992. The not so simple relationship between seismicity and oil production in the Permian Basin, West Texas. Pure and Applied Geophysics 139,
481e506.
Downie, R.C., Kronenberger, E., Maxwell, S.C., 2010. Using Microseismic Source
Parameters to Evaluate the Influence of Faults on Fracture Treatments e a
Geophysical Approach to Interpretation. SPE 134772.
Evans, K.F., Zappone, A., Kraft, T., Deichmann, N., Moia, F., 2012. A survey of the
induced seismic responses to fluid injection in geothermal and CO2 reservoirs
in Europe. Geothermics 41, 30e54.
184
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
Fritschen, R., 2009. Mining-induced seismicity in the Saarland, Germany. Pure and
Applied Geophysics 167, 77e89.
Frohlich, C., Hayward, C., Stump, B., Potter, E., 2011. The Dallas-Fort Worth earthquake sequence: october 2008 through may 2009. Bulletin of the Seismological
Society of America 101, 327e340.
Gahalaut, K., Gahalaut, V.K., 2010. Effect of the Zipingpu reservoir impoundment on
the occurrence of the 2008 Wenchuan earthquake and local seismicity.
Geophysical Journal International 183, 277e285.
Galybin, A.N., Grigovan, S.S., Mukhamediev, Sh.A., 1998. Model of Induced Seismicity Caused by Water Injection. SPE 47253, pp. 265e272.
Ge, S., Liu, M., Lu, N., Godt, J.W., Luo, G., 2009. Did the Zipingpu Reservoir trigger the
2008 Wenchuan earthquake? Geophysical Research Letters 36, L20315.
Gei, D., Eisner, L., Suhadolc, P., 2011. Feasibility of estimating vertical transverse
isotropy from microseismic data recorded by surface monitoring arrays.
Geophysics 76, WC117eWC126.
Geiser, P., Lacazette, A., Vermilye, J., 2012. Beyond “dots in a box”: an empirical
view of reservoir permeability with tomographic fracture imaging. First
Break, 63e69.
Genmo, Z., Huaran, C., Shuqin, M., Deyuan, Z., 1995. Research on earthquakes
induced by water injection in China. Pure and Applied Geophysics 145,
59e68.
Giardini, D., 2011. Induced Seismicity in Deep Heat Mining: Lessons from
Switzerland and Europe. Presentation to National Research Council Committee
on Induced Seismicity Potential in Energy Production Technologies. April 26,
Washington DC.
Gibbs, J.F., Healy, J.H., Raleigh, C.B., Coakley, J., 1973. Seismicity in the Rangely,
Colorado, area: 1962-1970. Bulletin of the Seismological Society of America 63,
1557e1570.
González, P.J., Tiampo, K.F., Palano, M., Cannavo, F., Fernández, J., 2012. The 2011
Lorca earthquake slip distribution controlled by groundwater crustal unloading.
Nature Geoscience 5, 821e825.
Gough, D.I., Gough, W.I., 1970. Load-induced earthquakes at Lake Kariba-II.
Geophysical Journal International 21, 79e101.
Grechka, V., 2010. Data-acquisition design for microseismic monitoring. The Leading Edge, 278e282.
Green, C.A., Styles, P., Baptie, B.J., 2012. Preese Hall Shale Gas Fracturing Review and
Recommendations for Induced Seismic Mitigation. <http://www.decc.gov.uk/
assets/decc/11/meeting-energy-demand/oil-gas/5055-preese-hall-shale-gasfracturing-review-and-recomm.pdf>.
Gupta, H.K., 1985. The present status of reservoir induced seismicity investigations
with special emphasis on Koyna earthquakes. Tectonophysics 118, 257e279.
Gupta, H.K., 2002. A review of recent studies of triggered earthquakes by artificial
water reservoirs with special emphasis on earthquakes in Koyna, India. EarthScience Reviews 58, 279e310.
Gutenberg, R., Richter, C.F., 1944. Frequency of earthquakes in California. Bulletin of
the Seismological Society of America 34, 185e188.
Hamilton, J.M., Mailer, A.V., Prins, M.D., 1992. Subsidence-induced shear failures
above oil and gas reservoirs. In: Tillerson, Wawersik (Eds.), Rock Mechanics.
Balkema, Rotterdam.
Hanks, T., Kanamori, H., 1979. A moment magnitude scale. Journal of Geophysical
Research 84, 2348e2350.
Häring, M.O., Schanz, U., Ladner, F., Dyer, B.C., 2008. Characterisation of the Basel 1
enhanced geothermal system. Geothermics 37, 469e495.
Holland, A., 2011. Examination of Possibly Induced Seismicity from Hydraulic
Fracturing in the Eola Field, Garvin County, Oklahoma. Oklahoma Geological
Survey Open-File Report OF1-2011.
Howe, A.M., Hayward, C.T., Stump, B.W., Frohlich, C., 2010. Analysis of recent earthquakes in Cleburne, Texas (Abstract). Seismological Research Letters 81, 379.
Hsieh, P.A., Bredehoeft, J.D., 1981. A reservoir analysis of the Denver earthquakes: a case of induced seismicity. Journal of Geophysical Research 86,
903e920.
Hubert, G., Kijko, A., Mcgarr, A., Ortlepp, W.D., 2006. Investigation into the Risks to
Miners, Mines, and the Public Associated with Large Seismic Events in Gold
Mining Districts.
Hulsey, B.J., Cornette, B., Pratt, D., 2010. Surface Microseismic Mapping Reveals
Details of the Marcellus Shale. SPE 138806.
Jalali, M., Memarian, H., Zare, M., Dusseault, M.B., 2008. Induced Seismicity Risk in
Irani Oil and Gas Fields. American Rock Mechanics Association.
Julian, B.R., Ross, A., Foulger, G.R., Evans, J.R., 1996. Three-dimensional seismic image
of a geothermal reservoir: The Geysers, California. Geophysical Research Letters
23, 685e688.
Kaieda, H., Sasaki, S., Wyborn, D., 2010. Comparison of characteristics of microearthquakes observed during hydraulic stimulation operations in Ogachi,
Hijiori and Cooper Basin HDR projects. In: Proceedings World Geothermal
Congress. Bali, Indonesia, pp. 25e29.
Kanamori, H., 1977. The energy release in great earthquakes. Journal of Geophysical
Research 82, 2981e2987.
Keiding, M., Árnadóttir, T., Jónsson, S., Decriem, J., Hooper, A., 2010. Plate boundary
deformation and man-made subsidence around geothermal fields on the Reykjanes Peninsula, Iceland. Journal of Volcanology and Geothermal Research 194,
139e149.
Keith, C.M., Simpson, D.W., Soboleva, O.V., 1982. Induced seismicity and style of
deformation at Nurek Reservoir, Tadjik SSR. Journal of Geophysical Research 87,
4609e4624.
Keranen, K.M., Savage, H.M., Abers, G.A., Cochran, E.S., in press. Potentially induced
earthquakes in Oklahoma, USA: links between wastewater injection and the
2011 M w 5.7 earthquake sequence. Geology.
King, G.E., 2010. Thirty Years of Shale Gas Fracturing: What Have We Learned?. SPE
119896.
Klose, C.D., 2007. Geomechanical modeling of the nucleation process of Australia’s
1989 M5.6 Newcastle earthquake. Earth and Planetary Science Letters 256,
547e553.
Kouznetsov, O., Sidorov, V., Katz, S., Chilingarian, G., 1994. Interrelationships
among seismic and short-term tectonic activity, oil and gas production, and
gas migration to the surface. Journal of Petroleum Science and Engineering
13, 57e63.
Kratz, M., Hill, A., Wessels, S., 2012. Identifying Fault Activation in Unconventional
Reservoirs in Real Time Using Microseismic Monitoring. SPE 153042.
Kugaenko, Y., Saltykov, V., Chebrov, V., 2005. Seismic situation and necessity of local
seismic monitoring in exploited Mutnovsky steam-hydrothermal field (Southern Kamchatka, Russia). In: Proceedings, World Geothermal Congress, Anatalya,
Turkey, April 24e29.
Lacazette, A., Geiser, P., 2013. Comment on Davies et al 2012-hydraulic fractures:
how far can they go? Marine and Petroleum Geology 43, 516e518.
Lachenbruch, A.H., Sass, J.H., 1980. Heat flow and energetics of the San Andreas fault
zone. Journal of Geophysical Research 85, 6185e6222.
Lahaie, F., Boyer, E., Grasso, J.R., Fourmaintraux, D., 1998. SPHSRM Production Study
as a Tool to Control the Efficiency of Reservoir Fracturing: The Lacq Case-Study.
SPE 47318.
Lei, X.-L., Yu, G., Ma, S., Wen, X., Wang, Q., 2008. Earthquakes induced by water
injection at w3 km depth within the Rongchang gas field, Chongqing, China.
Journal of Geophysical Research 113, B10310.
Li, T., Cai, M.F., Cai, M., 2007. A review of mining-induced seismicity in China. International Journal of Rock Mechanics and Mining Sciences 44, 1149e1171.
Lixin, Y., Zhao, D., Liu, C.L., 2012. Preliminary study of reservoir-induced seismicity
in the three Gorges Reservoir, China. Seismological Research Letters 83 (5),
806e814.
Majer, E.L., 17 November 2011. Induced Seismicity Associated with EGS Issues,
Status, Challenges, Needs. Australian Geothermal Meeting, Melbourne,
Australia.
Majer, E.L., Baria, R., Stark, M., Oates, S., Bommer, J., Smith, B., Asanuma, H., 2007.
Induced seismicity associated with enhanced geothermal systems. Geothermics
36 (3), 185e222.
Maxwell, S.C., Shemeta, J., Campbell, E., Quirk, D., 2008. Microseismic Deformation
Rate Monitoring. SPE 116596.
Maxwell, S.C., Jones, M., Parker, R., Miong, S., Leaney, S., Dorval, D., D’Amico, D.,
Logel, J., Anderson, E., Hammermaster, K., 2009. Fault Activation During Hydraulic Fracturing SEG Houston 2009 International Exposition and Annual
Meeting 1552e1556.
Maxwell, S.C., Cho, D., Pope, T., Jones, M., Cipolla, C., Mack, M., Henery, F., Leonard, J.,
2011. Enhanced Reservoir Characterisation Using Hydraulic Fracture Microseismicity. SPE 140449.
Mirzoev, K.M., Nikolaev, A.V., Lukk, A.A., Yunga, S.L., 2009. Induced seismicity and
the possibilities of controlled relaxation of tectonic stresses in the Earth’s crust.
Physics of the Solid Earth 45, 885e904.
National Academy of Sciences, 2012. Induced Seismicity Potential in Energy
Technologies.
Nicholson, C., 1992. Earthquakes associated with deep well activities- Comments
and case histories. In: Wawersik, T.A. (Ed.), Rock Mechanics. A.A. Balkema,
Brookfield, Vt, pp. 1079e1086.
Nicholson, C., Wesson, R.L., 1990. Earthquake Hazard Associated with Deep Well
Injection. a report to the U.S. Environmental Protection Agency.
Ohtake, M., 1974. Seismic activity induced by water injection at Matsushiro, Japan.
Journal of Physics of the Earth 22, 163e176.
Ottemöller, L., 2005. The 7 May 2001 induced seismic event in the Ekofisk oil field,
North Sea. Journal of Geophysical Research 110, 1e15.
Pechmann, J.C., Walter, W.R., Nava, S.J., Arabasz, W.J., 1995. The February 3, 1995 ML
5.1 seismic event in the Trona Mining District of Southwestern Wyoming.
Seismological Research Letters 66, 25e33.
Phillips, W.S., Rutledge, J.T., House, L.S., Fehler, M.C., 2002. Induced microearthquake
patterns in hydrocarbon and geothermal reservoirs: six case studies. Pure and
Applied Geophysics 159, 345e369.
Redmayne, D.W., 1988. Mining Induced Seismicity in UK Coalfields Identified on the
BGS National Seismograph Network. In: Geological Society, London, Engineering Geology Special Publications, vol. 5, pp. 405e413.
Roest, J.P.A., Kuilman, W., 1994. Geomechanical Analysis of Small Earthquakes at the
Eleveld Gas Reservoir. SPE 28097.
Rothé, J.P., 1970. Seismic artificiels. Tectonophysics 9, 215e238.
Rozhko, A.Y., 2010. Role of seepage forces on seismicity triggering. Journal of
Geophysical Research 115, B11314.
Scholz, C.H., 1990. The Mechanics of Earthquakes and Faulting. Cambridge Univ.
Press, Cambridge, p. 439.
Shapiro, S.A., Dinske, C., 2009. Fluid-induced seismicity: pressure diffusion and
hydraulic fracturing. Geophysical Prospecting 57, 301e310.
Stein, S., Wiens, D.A., Fujita, K., 1982. The 1966 Kremasta reservoir earthquake
sequence. Earth and Planetary Science Letters 59, 49e60.
Suckale, J., 2009. Induced seismicity in hydrocarbon fields. Advances in Geophysics
51, 55e106. (Chapter 2).
R. Davies et al. / Marine and Petroleum Geology 45 (2013) 171e185
Sykes, L.R., Sbar, M.L., 1973. Intraplate earthquakes, lithospheric stresses and the
driving mechanism of plate tecotnics. Nature 245, 298e302.
Vallejos, J.A., McKinnon, S.D., 2011. Correlations between mining and seismicity for
re-entry protocol development. International Journal of Rock Mechanics and
Mining Sciences 48, 616e625.
Van Eck, T., Goutbeek, F., Haak, H., Dost, B., 2006. Seismic hazard due to smallmagnitude shallow-source, induce earthquakes in the Netherlands. Engineering Geology 87, 105e121.
Van Poollen, H.K., Hoover, D.B., 1970. Waste disposal and earthquakes at the Rocky
Mountain Arsenal, Derby, Colorado. Journal of Petroleum Technology 22, 983e993.
Vulgamore, T., Clawson, T., Pope, C., Wolhart, S., Machovoe, S., Waltman, C., 2007.
Applying Hydraulic Fracture Diagnostics to Optimize Stimulations in the
Woodford Shale. SPE, 110029.
Warpinski, N.R., Branagan, P.T., Peterson, R.E., Wolhart, S.L., Uhl, J.E., 1998. Mapping
Hydraulic Fracture Growth and Geometry Using Microseismic Events Detected
by a Wireline Retrievable Accelerometer Array. SPE 40014.
185
Warpinski, N.R., Du, J., Zimmer, U., 2012. Measurements of Hydraulic-fractureinduced Sesimicity in Gas Shales. SPE 151597.
Wessels, S., Kratz, M., De La Pena, A., 2011. Identifying Fault Activation During
Hydraulic Stimulation in the Barnett Shale: Source Mechanisms, b Values, and
Energy Release Analyses of Microseismicity. In: SEG San Antonio 2011 Annual
Meeting, pp. 1643e1647.
Wolhart, S.L., Harting, T.A., Dahlem, J.E., Young, T.J., Mayerhofer, M.J., Lolon, E.P.,
2005. Hydraulic Fracture Diagnostics Used to Optimize Development in the
Jonah Field. SPE 102528.
Zhong, Y.Z., Gao, C.B., Bai, Y., 1997. Induced seismicity in Liaoning Province, China.
Pure and Applied Geophysics 150, 461e472.
Zoback, M.D., Harjes, H.-P., 1997. Injection-induced earthquakes and crustal stress at
9 km depth. Journal of Geophysical Research 102, 18,477e18,491.
Zoback, M.D., Hickman, S., 1982. In Situ study of the physical mechanisms
controlling induced seismicity. Journal of Geophysical Research 87, 6959e
6974.
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement