Hydraulicfracturingandits

rela1onshiptoinduced

seismicityin1meandspace

DaveEaton

DepartmentofGeoscience

KeyPoints

§  IntheCrookedLakearea,steeplydippingfaultsare

ac=vatedby:

-  elevatedpore-pressure(àpersistentseismicity,=mescale~months)

-  poroelas=cstresschange(àtransientseismicity,mainlyconfinedto

treatmentinterval)

§  Marcellus:focalmechanismsforcompositeevents

§  NorthernMontney:EmpiricalHazardMatrix

§  FiniteElementfaultsimula=ons:

-  roleofcohesionforwellhealed(inac=ve)faults

-  largesurfacedisplacementforshallowreversefaults

§  Somecurrentac=vi=es

0 30 60 90

2

1

3

5

4

6

Days after 2015/01/01

− − − −117˚30' 117˚24' 117˚18' 117˚12'

54˚24'

54˚30'

injection well

Crooked

Lk

Longitude

La

titu

de

km0 5

MW<2

2 <3≤MW

M ≥w 3

Σ=-2.7

Σ=-1.7

Σ=-1.5

Σ=-1.5

CrookedLakeArea:W2015

BaoandEaton,SSA2016

MP

a

MW

0

3

6

10

m4

3

M(m

ax)1

−1012345

65

70

75

Dec 14 Jan 15 Feb 15 Mar 15− − − −

S1 S2 S3

Seismicityvs.Injec1onData

•  Largesteventduringflowback−butunusuallylowfluidrecovery

•  EpisodicseismicitypersiststhroughoutW2015(S1,S2,S3)butnottypical

aUershocksequence

•  Maximummagnitude(MW3.9)compa=ble(barely)withMcGarrformula

BaoandEaton,SSA2016

Dec 14 Jan 15 Feb 15 Mar 15− − − −

0

2

4

10

m4

3

6

−1012345

70

75

80

Dec 14 Jan 15 Feb 15 Mar 15− − − −

M(m

ax)

MP

a

MW

5

MP

a

MW

0

3

6

10

m4

3

M(m

ax)1

−1012345

65

70

75

Dec 14 Jan 15 Feb 15 Mar 15− − − −

S1 S2 S3

S2: τ ≈4days

r=9.2±2.0km

RemoteTriggeringofS2?

BaoandEaton,SSA2016

−0.2 0 0.2 0.4 0.6 0.8 1 1.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4

4.1

4.2

Distance East (km)

Depth

(km

)

east s

trand

west s

trand

hz wells

crystalline basement MW 3.9

Duvernay shale

de

pth

(km

)

distance east (km)

Mul1plestrands–varyingresponse

East:transient

West:persistent

CrossSec=onW E

Migra=on

BaoandEaton,SSA2016

MarcellusExperiment(2014)

10portablebroadbandsta=onsinstalledtorecord11-welltreatment

SeeposterbyZhangandEaton

Focalmechanismofcompositeevents

DepthSec=on

Sh/Pra=o

FocalMechanism

-jackknifetest

SeeposterbyZhangandEaton

MW4.62015/08/18

h=4km

BCOGC2014

Mahanietal.,BSSA,inpress

MontneySeismicity

Finite-ElementModelling

ModifiedfromSaDariandEaton,Tectonophysics,inreview

•  2-DFEsimula=onyields

realis=cscaling,

includingslip/area,

stressdrop,shapefactor

anddynamicovershoot

•  Predictssimplemodel

forco-seismicstress

droptensor

•  Unlikeac=vefault

systems,cohesionmay

exertasignificant

controlonfaultrheology

Amplifiedgrounddisplacement?

SeeposterbySaDariandEaton

ShallowReverseFault

Free-surfaceeffect

Distance

Depth

SeeposterbySaDariandEaton

HazardMatrixApproach

Waltersetal.,SRL,2015

Opera=onalFactor

e.g.Cumula=veInjectedVolume

Ac=vityLevel

e.g.MaximumPriorMagnitude

Hit

Constructa“hitmap”asfollows.

1.Foreachrecordedevent,assignan

opera=onalfactor(e.g.cumula=ve

volume)andac=vitylevel(e.g.

maximumprioreventwithina

specified=mewindow).

2.Testfor“hit”–occurrenceofa

subsequenteventthatmeetscriteria

(e.g.magnitude,=mewindow).

3.Ifhit,addzeros,onestomapas

shown.

EmpiricalHazardMatrix

50%

75%

25%

50%

Random Tradeoff

Opera=onal

TippingPoint

Ac=vity

TippingPoint

EHMTemplates

HitMap:M≥1innext4days

NorthernMontneyEHMs

Datasource:Mahanietal.,BSSA,inpress

TippingPoint?

CourtesyM.Rempel,BScseniorthesisproject

HitMap:M≥2.5innext21days

Tradeoff?

Datasource:Mahanietal.,BSSA,inpress

NorthernMontneyEHMs

CourtesyM.Rempel,BScseniorthesisproject

AUershocks

Foreshocks

CurrentAc1vi1es

•  DevelopingaPython-

basedworkflowfor

matched-filtering

analysis

•  Applyingthisapproach

toW2016seismicity,

usingRV,DS(NMX/UC)

andothernetworks

SeeposterbyVragovandEaton

CurrentAc1vi1es

•  Ongoingfracprogram

(startedthisweek)

•  Dualmonitoring:

inducedseismicityand

microseismic

•  6broadbandsta=ons+

accelerometerinstalled

forUCbyNMX

•  Holdbackondatarelease

ImagecourtesyofMichaelLaporte,Nanometrics

Acknowledgements

•  TransAlta,NanometricsandNSERC(InducedSeismicityProcessesCRD)

•  Repsol,NanometricsandCanadianDiscoveryLtd.(dataforSciencepaper)

•  NobleEnergyandSpectraseis(MarcellusSurfaceMicroseismic

Experiment)

•  Chevron,ConocoPhillips,AquaTerra,Nanometrics(IRC)

•  AliMahani(preprintofnorthernMontneyBSSApaper)