Geomechanical Assessment of Seismicity from Hydraulic Fracturing
Shawn MaxwellInduced Seismicity Workshop May 2015
Western Canada Sedimentary Basin
NRCan Reported Earthquakes NEBC/NWAB
CAPP Guidelines/Industry Protocols
Assess Hazard
Communicate/Prepare
Monitor
Respond(Mitigate)
AvoidFaults
• Geomechanical conditions• Past seismicity• Local experiences• Risk (public/infrastructure)
• Alter well design• Alter staging
• Mitigation plan• Authorize reaction
BCOGC&AER>M 4M 2-4<M 2
• Change rate?
• Change volume?
• Skip stages?
• Shut down?
• Flow back?
Repsol Case Study
Maxwell, Zhang, Damjanac, Mas Ivars, Pérez Pérez and Stockhausen: EAGE 2015
Shear (m)
Mw=-0.1
AER: Duvernay Shale
NRCAN website
AER Subsurface order 2015-007: Mandatory monitoring to at least ML 2
“must implement its induced seismicity plan in a manner that eliminates or reduces further seismic events caused by or resulting from hydraulic fracturing operations.”
Changing Injection Parameters
7
4
2
0
-2
Ma
gnit
ud
e
4
2
0
-2
Ma
gnit
ud
e
Orange symbols: Montney induced seismicityCourtesy Dan Walker BCOGC
Microseismic GeomechanicsPore Pressure Fracture Opening
Fracture Shearing Synthetic Microseismic
Horn River Basin
fault
well
clusters
Case 1 Case 2 Case 3
(Snelling et al, 2010)
Induced Seismicity Application:Fault Activation
10
10
Relative Seismic Hazard
Microseismic Fault Activation Example
Time (min)
0 20 40 60 80 100 120
Seis
mic
Mo
men
t (N
m)
0
1e+7
2e+7
3e+7
4e+7
5e+7
6e+7
Pre
ssu
re (
psi)
-6000
-4000
-2000
0
2000
4000
6000
8000
Rate
(b
pm
)
-10
0
10
20
30
40
50
60
Triggered Tectonic Energy Release
Induced Hydraulic FractureEnergy ReleaseSPE116596
Energy Release Rate Trends
Time (min)
0 20 40 60 80 100 120
Seis
mic
Mo
men
t (N
m)
0
1e+7
2e+7
3e+7
4e+7
5e+7
6e+7
Pre
ssu
re (
psi)
-6000
-4000
-2000
0
2000
4000
6000
8000
Rate
(b
pm
)
-10
0
10
20
30
40
50
60
Time (min)
0 50 100 150 200 250
Pre
ssur
e (M
Pa)
0
20
40
60
80
Rat
e (m
3 /min
)
0
1
2
3
4
5
Sei
smic
Mom
ent (
Nm
)
0
2e+8
4e+8
6e+8
8e+8
1e+9
Can We Manage Aseismic Fault Creep?
Time (min)
0 20 40 60 80 100 120
Eff
icie
ncy
1e-10
1e-9
1e-8
1e-7
1e-6
Microseismic
AseismicHydraulic Energy (J)
1e+7 1e+8 1e+9 1e+10 1e+11 1e+12 1e+13 1e+14 1e+15
Sei
smic
Ene
rgy
(J)
1e+0
1e+1
1e+2
1e+3
1e+4
1e+5
1e+6
1e+7
1e+8
1e+9
1e+10
1e+11
1e+12
OriginalNEBCHRB (stage)HRB (pad)PH (stage)PH (well)
1%100%
.01%
.0001%
.000001%
Maximum
Blackpool
?
Can we push to many small events (manage b-value)?
Can we manage aseismic ‘creep’?
Controlled vs Unintentional Slip?
Board et al., 1982
Tadokoro et al., 2000
Rangely Colorado
Rayleigh et al., 1976
Magnitude Calibration
Sonley and Atkinson, 2005
BCOGC & AER
>M 4M 2-4
<M 2
Magnitude scale?ML MN MW ???
Need a calibrated magnitude scale for small events at close distance consistent with NRCAN
Key Questions
17
Definition of ‘best practices’
How can we better characterize (conditions & hazard)?
Reliability of traffic light systems?
Cumulative effect of repeated fracturing?
What is the effectiveness of various mitigation options?
Does $50 bbl oil reduce hazard??