STRATA反演软件介绍(精)课件.ppt

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1、EARTHIMAGINGSOLUTIONS1STRATA2Dand3DPost-StackSeismicModelling,Processing&April1999Inversion2STRATAisaninteractive2Dand3Dmodellingandinversionprogramwhichtransformspost-stackseismictracestovelocityoracousticimpedancetraces.Theprogramincludesoptionsforbasicseismicprocessing,waveletextraction,logedit

2、ingandinterpretation,aswellasdifferentmethodsofperforminginversion.3OverviewofInversionPre-StackInversionTravelTimeInversion(Tomography)AmplitudeInversion(AVO)WaveFieldInversionBandlimitedInversionSparse-spikeInversionModel-basedInversionPost-StackInversionSeismicInversionMethodsAmplitudeInversion(

3、STRATA)4Theinversionprocessistodeterminetheearthimpedancefromthegivenseismictracebasedontheconvolutionalmodelseismic=wavelet*reflectivity+noiseAssumptionsTheseismicdataarealreadystacked,migratedandnomultiples.Eachtracedependsonlyontheimpedancedirectlybelowthetracelocation.Thewaveletisconstantandnot

4、varyingwithtime.Thenoiseisrandom,whitenoise,uncorrelatedwiththeseismic.Thereisnocoherentnoise.Objective5Non-UniquenessProblem!非单值问题（CHJ注）Allinversionalgorithmssufferfromthenon-uniquenessproblem.Thismeansthatthereismorethanonepossiblegeologicalmodelconsistentwiththeseismicdata.Inpractice,thisproblem

5、ishandledbyusinggeologicalconstraints,providedbywelllogs.6BasicConceptofSTRATASeismicDataVelocity/DensityControl(Logs)BuildModelInvertSeismic7BasicSteps(e.g.ModelBasedInversion)(1)Readseismicandwelllogs.(2)Extractastatisticalwaveletfromtheseismic.Correlatelogsandextractagainthebestwaveletusingthewe

6、lllogs.(4)Buildinitialmodel.Setupverticalandlateralinterpolation.(5)Applyinversionandvalidatetheoutputimpedanceandsynthetic.(3)Pickorimporthorizons.ImportWellLogOpenSeismicProcessSeismicExtractWaveletExtractWaveletusingLogCreateSyntheticPickSeismicBuildModelInversionCorrelateLog8Step1:DataInput(1)R

7、eadseismicandwelllogs.(2)Extractastatisticalwaveletfromtheseismic.Correlatelogsandextractagainthebestwaveletusingthewelllogs.(4)Buildinitialmodel.Setupverticalandlateralinterpolation.(5)Applyinversionandval