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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??