简介:<正>REPLACEMENTPATTERNSOFGEOTECTONICUNITSLiYuping(Dept.ofChemicalScienceandEngineering,HunanUniv.,Changsha,China,410082)replacementpattern,geotectonicunit,DiwatheoryBaseupontheDiwatheoryandthestudiesofevolutionprocessofgeotectonicunits,thispaperhasadvancedthattherearemanyreplacementpatternsofthegeotectonicu-nitsintheirevolutionprocess.Therearethreereplacementpatterns(eg.suddenchange(nor-mal)pattern,gradualchangeandprogressivepattern)duringtheplatformregionsubstitutesthegeosynclinalregionandthreereplacementpatterns(eg.normalpattern,surpassivepatternandprogressivepattern)whentheDiwaregiondevelopsfrompre-Diwaregions.Theknowl-edgeoftheseregularityisofimportantsignificanceforustodeeplystudytheevolutionofgeo-tectonicunitandthedevelopmentofthecrust.
简介:ThenorthernmarginoftheAlxablockisthejunctionofatectonicunits.Fourfirst-ordertectonicunitsaredistinguished:1.theYaganstructuralzonecharacteristicofanimmatureislandarc;2.theZhusileng-Hangwulastructuralzone,whichwasapassivecontinentalmarginintheEarlyPalaeozoicandwastransformedintoanactivecontinentalmarginintheLatePalaeozoic;3.theShalazhastructuralzonecharacteristicofamatureislandarc;4.theNuru-Langshanstructuralzone,whichwasaProterozoicorogenicbeltandlaterevolvedintoanextensionaltranstionalcrustinthePalaeozoic.Theabove-mentionedtectonicunitsdifferremarkablyinsedimentaryformations,magmaticrockassociations,metamorphismandgeochemistryandareboundedbyfaultsbetweenoneanother.
简介:TightzonesofthegasbearingKanganandDalanformationsoftheSouthParsgasfieldcontainaconsiderableamountofunsweptgasduetotheirlowporosity,lowpermeabilityandisolatedporetypes.Thecurrentstudy,integratescoredata,rockelasticpropertiesand3Dseismicattributestodelineatetightandlow-reservoir-qualityzonesoftheSouthParsgasfield.Inthefirststep,thedynamicreservoirgeomechanicalparameterswerecalculatedbasedonempiricalrelationshipsfromwelllogdata.Thelog-derivedelasticmoduliwerevalidatedwiththeavailablelaboratorymeasurementsofcoredata.CrossplotsbetweenestimatedporosityandelasticparametersbasedonYoung'smodulusindicatethatlowporosityzonecoincidewithhighvaluesofYoung'smodule.Theresultswerevalidatedwithpetrographicstudiesoftheavailablethinsections.Thecoresampleswithlowporosityandpermeabilityarecorrelatedwithstrongrockswithtightmatrixframeworksandhighelasticvalues.Subsequently,rockelasticpropertiesincludingYoung'smodulusandPoisson'sratioalongwithporositywereestimatedbyusingneuralnetworksfromacollectionof3Dpost-stackseismicattributes,suchasacousticimpedance(AI),instantaneousphaseofAIandapparentpolarity.Distinguishinglowreservoirqualityareasinpayzoneswithunsweptgasisthenfacilitatedbylocatinglowporosityandhighelasticmodulusvalues.Anhydritezonesareidentifiedandeliminatedasnon-payzonesduetotheircharacterizationofzeroporosityandhighYoungmodulusvalues.Themethodologydescribedhasapplicationsforunconventionalreservoirsmoregenerally,becauseitisabletodistinguishlowporosityandpermeabilityzonesthatarepotentiallyproductivefromthoseunprospectivezoneswithnegligiblereservoirquality.