岩石物理敏感性分析

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1、GeneralSensitivityanalysisisthestudyofhowthevariation(uncertainty)intheoutputofamathematicalmodelcanbeapportioned,qualitativelyorquantitatively,tod讦ferentsourcesofvariation(namedparameters11inTechlog)intheinputofthemodel.Putanotherway,itisatechniqueforsystematicallychangingparametersinamodeltodeterm

2、inetheeffectsofsuchchanges.Inmoregeneraltermsuncertaintyandsensitivityanalysisinvestigatetherobustnessofamodelwhenthemodelincludessomeformofmathematicalmodel!ng.SensitivityanalysisareusefulinTechLogsoasto1・increasetheunderstandingorquantificationofthesystem(i.e.understandingrelationshipsbetweeninput

3、andoutputvariables)and2.modeldevelopment(i.e・searchingforerrorsinthemodel).SensitivitiesinTechlogThesensitivityanalysiscanbelaunchedfromtheSummariesmethodtabintheQuantiworkflowbyclickingontheicon"'Displaythesensitivity...11displayedonthemethodleftsidebar.Theanalysiswillbedoneforeachzoneseparatelyand

4、theresultsaredisplayedinmatrixcrossplots.Thecontrollingparametersfortheanalysisarefoundinthepropertiesdocwindowofthe"Summaries1'method,underthetabHsensitivity”.SensitivityAnalysispropertiesinTechlogNumberofiterations:numberofcalculationsteps・Forexample,arangeofporositybetween0and0.5[v/v]withanumberi

5、terationsof10willcalculatethesensitivityforeachincrementof0.05[v/v].Refereneeused:sincethesummariesalgorithmcanbelaunchedusingseveralreferencesatonce(MD,TVD/ss),itisimportanttospecifywhichrefereneewillbeusedforthesensitivityanalysis.Bydefault,theMeasureddepthwillbeused.Theanalysiscanbelaunchedsepara

6、telyforeachinputcurvebydeactivatingalltheothercurves.Ifseveralcutoffareactivated,theresultsarenotindependent:thesensitivityofthepaywillbedependedintheresultsofthereswhichisdependedintheresultsoftherock・Foreachinputadefinitionofarangeandacutoffisneeded.■Therangeforthesensitivitycanbedifferentthanther

7、angethatisusedtocalculatethesummaries.■Thechosencutoff(minormax)willbethecutoffthatwillbeusedtocontroltherange.Example:thesensitivityrangesforaporositycurvewithminvalueof0.1[v/v],maxvalueof0・3[v/v],4c