IS-01
description
Transcript of IS-01
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Borehole Seismology: Fundamentals and Applications
Prof. Dr. Marco Bohnhoff
Helmholtz-Centre Potsdam GFZ and Free University Berlin
Contact: [email protected]
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
IntroductiontoBoreholeSeismology
Whydownhole?ChallengesandStateoftheArt
CaseStudiesofDownholePassiveSeismicMonitoring
InducedseismicityattheBerlingeothermalfieldinElSalvadorSeismicmonitoringofCO2 storageandleakageatthePennWestEORpilot(CA)
ConcludingRemarks
PresentationOutline
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
(inalphabeticalorder,coauthorsofreferredownpaper)
Bulut,Fatih(GFZPotsdam)Chalaturnyk,Rick(UAlberta,CA)Dresen,Georg(GFZPotsdam)Ellsworth,Bill(USGSMenloPark)Ito,Hisao(JAMSTECTokyo)Kwiatek,Grzegorz(GFZPotsdam)Martinez,Patricia(GFZPotsdam)Zoback,Mark(StanfordU)
withcontributionsfrom:
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
PassiveSeismicMonitoring:Motivation210 12345 67
Earthquakemagnitude(Richterscale)
Magnitude -2 / -1Rupture surface mSlip mm
Magnitude 7+Rupture surface >10 kmSlip m
(reconstruction)
detectthesmallones betterunderstandthelargeones
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
(Bohnhoffetal.,ILP,2010)
EarthquakeMagnitudeRanges
Length and displacement approx. and appropriate for stress drops of 3 MPa* 1 Aki is defined as 1018 Nm and named after Keiiti Aki who pioneered the use of seismic moment in theory and practice** the term microearthquake traditionally refers to M
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Drillingisexpensive(inoil/gasindustrydrillingcostsare>10timesthecostsforpresitesurveys...).
Drillingisriskyandlogisticallyextremelydifficult.Downhole instrumentsneedtooperateatelevatedpressureandtemperatureconditions.
BUT:Downholeseismicmonitoring...
...allowstomonitoratsubstantiallyreducednoiseconditionstherebyimprovingsignaltonoiseratio,magnitudedetectionthresholdandprecisionofhypocenterdetermination.
...allowstobroadenthefrequencybandoftherecordedwavefieldthroughrecordingalsohigherfrequencycontents.
HOWEVER,challengesinboreholeseismologyareasecuredeploymentofsensors(ensuringgoodcouplingtotheformation),safedatatransmissiontothesurface,formationpressure/temperature/fluids.
WhyGoingDownhole?
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
CouplingofBoreholeSeismometers
Agoodcouplingofthesensorstothecasing/formationisessentialtogeneratereasonablygooddataquality.
Thiscanbeachievedthrough:
Sandbackfillingsensorsatthebaseoftheborehole(temporaryorpermanent)
Cementingsensorsinboreholeorbehindcasing(permanent)
Mechanicalcouplingofthesensortotheboreholewallorcasing(mostlytemporary)
Temporarydeploymentinanopenholesetting
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
CouplingofBoreholeSeismometers
Agoodcouplingofthesensorstotheformationisessentialtogenerategooddataquality
Canbeachievedthrough:
Sandingsensorsatboreholebase(temporaryorpermanent)
Cementingsensorsinboreholeorbehindcasing(permament)
mechanicalcouplingtoborewallorcasing(mostlytemporary)
Examplefroma2x83Cboreholegeophonearray
Deploymentofaboreholegeophone(ESGLtd.)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
OrientationofBoreholeSeismometers Nodirectinfluenceonorientationofsensorsinboreholealthoughessential. Sensorsneedtobeverticallyorientedwithinafewdegree(or:gimbledsensor). Horizontalorientationcanbedeterminedthroughcheckshots(providesalso.feedbackonsensorquality,couplingandformationvelocity).
Array1Array2
= injection = seismic sensor = well trajectory
checkshots
(Bohnhoffetal.,IJGGC,2010)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
OrientationofBoreholeSeismometers Nodirectinfluenceonorientationofsensorsinboreholealthoughessential. Sensorsneedtobeverticallyorientedwithinafewdegree(or:gimbledsensor). Horizontalorientationcanbedeterminedthroughcheckshots(providesalso.feedbackonsensorquality,couplingandformationvelocity).
Array2
Array1
Vp/Vs=1.84(Vp=4.8km/s,Vs=2.6km/s)
PWaves
BoreholeSeismograms Wadatidiagram
(quasi)SWaves
(Bohnhoffetal.,IJGGC,2010)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Atypicalfrequencybandofaseismicsurfacestationextendsupto~100Hz Higherfrequenciesarenotseenduetoattenuationintheshallowformation
ObtainingHighFrequencySignals3
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500HzData:Filtered1100Hz,2s
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Samedata butbandpassfilteredabove100Hzdemonstratingthebenefitof conditionsallowingrecordalsohigherfrequencycontentsofthe seismicwavefield.
ObtainingHighFrequencySignals3
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500HzData:Filtered100240Hz,2s
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
SignalToNoiseImprovementWithDepth
(P.Malin,pers.comm.)
Qualityofseismicrecordingstoalargeextentisdefined
bythenoiseconditionsatthesensor.
Noiseconditionsimprovesubstantiallywithdepth.
Involvingdrillingcostsseveralhundredsofmetersrepresentanoptimumforthereturnoninvestmentindownholepassiveseismicmonitoring.
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
DownholeSeismologyinFundamentalResearch Sincefirstseismicnetworksin1910/20ssystematicdensification(regional/global).TodayMc 2inwesternUS,Japan,westernEurope.
1986:InstallationoftheParkfieldHighResolutionSeismicNetwork(HRSN):Depthofsensors65550m(mostly250m),datasampledat250Hz.
HRSNParkfield
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
(Rutledgeetal.,BSSA,1998)
Mostlyshorttermdeploymentsfordownholeseismicmonitoringofreservoirstimulation(hydrocarbon,geothermal,shalegasreservoirs).
Usuallyseismometerstringsinoneorseveralmonitoringwells closetoreservoir.
DownholeSeismicMonitoringinIndustry
(Kwiateketal.,ActaGeophys.,2010)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
(Okadaetal.,EPS,2004)
1995 2003
BoreholeSeismologyinJapan:StationDistribution Highsensitivityboreholestations,typicallyat100mdepth
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Casestudy1:
MonitoringInducedSeismicityintheBerlinGeothermalField,ElSalvador
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
1km
BerlinGeothermalField:Location LocatedontheflancsofdormantvolcanoCerroTecapa. 8productionwellsand10injectionwells(closedfluidcirculation).
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
S N
Injectionwell
1km
SHmax
BoreholeSeismometerNetwork 12boreholesensors(nat.frequencies1/4,5/5,5/30Hz)sampled 243000Hz. 3stimulationcampaignsof3weekseachat2differentdepthintervals.
Depthsection Mapview
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
WholedatasetDuringinjectionintoTR8A1km
RelevanceofApplyingstateoftheartProcessingTechniques:RelativeRelocation
ApplicationofhypoDDtechnique(Waldhauser/Ellsworth,2001)totraveltimepicks.
Systematicshiftofhypocenterlocationstowardsthegeothermalfield(wrtinitialabsolutelocations).
Strongclusteringofeventsaroundinjectionwells.
Clearrelationbetweenseismiceventsandstimulation.
(Kwiateketal.,subm.)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
1km
Applicationofwaveformcrosscorrelationtechniquetodeterminesignalsimilarityatindividualboreholesensors.
Identificationof9eventfamiliesdisplayingsimilarruptureprocesses.
FocusonseismicityatwellTR8Ainthefollowing(deepbluefamily).
RelevanceofApplyingstateoftheartProcessingTechniques:ClusterAnalysis
(Kwiateketal.,subm.)
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Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Borehole Seismology
SHmax
250m
Wellheadpressure Injectionrate
Spatiotemporaloccurrenceofseismicity Temporalmigrationofseismicityawayfromthereservoirtowardsafaultplane. Abruptincreaseofeventmagnitudesandchangeofmigrationduringshutin.
(Kwiateketal.,subm.)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Initialspectralfittingmethod Afterspectralratiorefinement
RelevanceofApplyingstateoftheartProcessingTechniques:SourceParameters
Determinationofsourceparametersusingarefinedspectralratiotechnique Strongimprovementsonthequalityofsourceparameters(M0,r0,)
(Kwiateketal.,subm.)
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Whilegoodqualitydataisaprerequisiteforanystudy,stateoftheartevaluationmethodsareessentialtoobtainoptimumandreliableresults.
Relativerelocationofhypocentersallowstoidentifyasystematicmigrationofeventstowardsandalongmappedfaultplanes,probablyinitiatedbythe
elevateddownhole pressure duringinjection.
Largermagnitudeeventsandseismicityclustersareobservedduringshutinphases.
Seismicityoccursinpreviouslyactiveareasonlyoncetheearliermaximumdownholepressureisexceeded(Kaisereffect).
BerlinGeothermalField:LessonsLearnt
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Casestudy2:
DownholepassiveseismicmonitoringofCO2storageandleakageinthePennWestEORpilot
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
PassiveSeismicMonitoring(PSM)isafrequentlyusedtechniquetostudynaturalandfluidinjectioninducedmicroseismicityalongfaultzonesandinhydrocarbonandgeothermalreservoirs.
MonitoringinducedseismicityintheframeofCO2 storageisstillinitsinfancyandhasnotyetbeenadressedsystematicallydespiteits greatpotential.
WereportonPSMinthePembinaOilFieldtoanalyzeCO2 leakageandtopotentiallycharacterizetheCO2 storagereservoirusinginducedmicroseismicity.
PassiveSeismicMonitoringofCO2 Storage
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
ThePennWestCO2 InjectionProject Location:PembinaOilField,westernCanada;EORProject. Monitoringwellat350mdistancefrominjectorwell(I1)
butonly35mawayfromproducerwellP1.
P1 P4
Monitoringwell
P6
P2 P5P3
I1 I2
Injectionwell
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
8threecomponentgeophones sensorspacing20mat1500to
1640mdepth 24Hznaturalfrequency 1kHzsamplingfrequency
1302m
1500m
1640m
BellyRiver
Wapiabi
Cardium(CO2 reservoir)
Blackstone
Geophone
Pressure/TemperatureFluidsample
Instrumentation
Lithology
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PennWestDownholeGeophoneArray
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Objectives:MicroseismicandLeakageMonitoring
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Absenceoftypicalsignaturesofmicroseismiceventsinspectogramsofcontinuousdata
Dominantenergyupto200Hz,clearindicationof50Hzsignalsandmultiples
Noobviouscorrelationbetweenindividualsensors
Usefultooltoquantifysignalqualityofindividualsensors
SpectralAnalysisofWaveformRecordings
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
SystematicsearchfornoiselevelchangesframingthetimeofaknownCO2leakage(outburstwithinmonitoringwell)
Result:Clearincreaseofthenoiselevelduringrelevanttime.But
AnalysisofNoiseLevelsatIndividualSensors
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
NoiselevelduringCO2 Accident detected noise level increase is not simultaneous.
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Frequencycontent:
Noiseanalysis:
STA/LTA:
Lowfrequencysignals:
Mostlyin[0,50]Hz. Abundantsignalswithenergyupto500Hz. Studyofreliabilityofeachsensor. IdentificationofsignalsrelatedwiththeCO2/CH4
outflow.
Numerouspotentialeventsfoundbutooweaktobefurtheranalyzed.
Observedsignalsnotmatureenoughtoverifyoccurrenceoflowfrequencyeventsduringinjection.
PennWestStudy:LessionsLearntNoevidencefoundforinducedmicroseismiceventsatMw>1.
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
(Casestudy3):
DownholepassiveseismicmonitoringofnaturalmicroseismicityattheMarmaraSeismicGap,NW
Turkey theGONAFproject.
TalkonThursdaymorninginTechnicalSessionS1:DevelopmentofSeismicObservationinDeepBoreholeanditsApplications
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
SomeGeneralConclusions
Recentdevelopmentsindownholepassiveseismicmonitoringtechnologyallowtorecordhighqualitydatasetsofmicroseismicitywiththepotentialofaddressingvariousrelevantseismologicaltopics.
CasestudiesfrompassiveseismicmonitoringwerediscussedstressingthatBasicandAppliedSeismologyaregenerallystronglyinterconnectedaddressingsimilartopics.
Futurechallengesinpassiveseismicmonitoringareintensifyingthe(permanent)deploymentofdownholeseismicinstrumentation
ensuringlongtermoperationatimprovednoiseconditions,recordingalsothehigherfrequenciesoftheseismicwavefield.
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Borehole Seismology
Prof. Dr. Marco Bohnhoff Kashiwazaki, Nov7 2012
Thank you for your attention!