简介：Themeasurementofundergroundmediumvariationusingarepeatedartificialsourcehasgraduallybecomeanimportantgoaltopursue.Inrecentyears,wehavedevelopedandimprovedatechnologysystemwithlargecapacityairgunsexcitedinlandreservoirsbytransplantingmarineseismicexplorationtechnology.Theexcitationeffecthasacloserelationshiptoairguncapacity,waterenvironment,andexcitationconditions.Inviewthatlargecapacityairgunmustbeexcitedwithoutawaterenvironment,weexpandthesystemtouseindownhole.BasedontheBHS-2200LLdownholeairgunwithacapacityof250in3,thispapercarriesoutacomparativeanalysisonthecharacteristicsofanairgunsourceexcitedin0.2m-and5.0m-diameterwells,andtheresultsshowthat:(1)Thedominantfrequencyoftheairgunsignalexcitedina5.0mwellismainlyfrom10Hzto40Hz,lowerthanthatina0.2mwell,andthelargerbodyofwaterisgoodforbubbleoscillation.(2)Intermsofexcitingenergy,thesignalexcitedina5.0mwellhasstrongerenergythanina0.2mwell,withadifferenceof1orderinmagnitude,andthesignalcanbedetectedupto9kmexcitedina5.0mwellwithasingleshot.(3)Theairgunsignalhasgoodrepeatabilityinbothexcitationwells.Thedownholeairgunexcitationtechnologysystemhaspotentialapplicationindynamicmonitoringnearafaultzonewithasmallscalerange,explorationofoilandmineralresources,andmodernurbangeophysicalenvironment.

简介：Basedonthedatasynthesissimulationandtheactualprocessingoftheairgunseismicsourcesignal,threequantitativeindicatorsofsignal-to-noiseratio,waveformcorrelationcoefficientandphaseoffset,aresuperimposed.Wesystematicallyevaluatethefunctionsofthefollowingthreestackmethodsincludinglinearity,phaseweightingandS-transformintheextractionofweaksignalsunderstrongbackgroundnoiseandquantitativelyestimatethereliabilityofthestackresults.Throughthecomprehensivediscussionoftheabovethreemethodsofstackresults,thepreliminarycomparativeanalysisbelievesthatthelinearstacksignal-to-noiseratioislow,butthewaveformdistortionisminimal;thephase-weightedsuperimposedsignal-to-noiseratioishighandthephaseoffsetissmall,buttheresultsofthewaveformqualityandlinearstackarelargerthanthedeviation;theS-transformstackhasarelativelyhighersignal-to-noiseratioandasmalllossofwaveformamplitude,butthereisacertainphaseshiftphenomenon.Itisthereforesuggestedthatlinearstacktechnologyshouldbeusedwhentherequirementsofbothwaveformqualityandtimeprecisionarehigh.However,theselectionofthestackmethodwhentheairgunsourceexcitationislimitedshouldbeemphasized.Ifhighfidelityisrequired,theS-transformstackmethodshouldbeselected;iftherequiredtimeishigh,accuracycanbeselectedbyphase-weightedstackmethodtoachievereasonableextractionofweaksignals.

简介：TheenergyradiationprocessofanairgunseismicsourceinlandreservoirisstudiedbasedontheunderwaterwaveletdatacollectedintheairgunexcitationexperimentsinBinchuan,Yunnan,China.Theempiricalformulaforcalculatingthebubblepulsationperiodandthemaximumradiusoftheunderwaterairgunseismicsourceisobtained.Theresultsshowthat:①Theenergyradiationefficiencyishigherverticallythanhorizontally.②Theverticalbubbleenergyradiationefficiencyincreaseswiththeincreaseoftheairsupplypressure.③Theverticalenergyradiationefficiencyoftheairgunseismicsourceis9.4%whentheairsupplypressureis15MPa.④Thehighertheairsupplypressure,thefurtherthepropagatingdistanceofthesuperposition-enhancedpressurewaveofanairgunsource.

简介：WeuseddatafromtheXinjiangDigitalSeismicNetworkandPSD(PowerSpectralDensity)methodtoperformnoiselevelassessmentforsixstations.Wecalculatedthemedianofthepowerspectraldensitytoevaluatethenoiselevelofdifferentstations.Afterthecomparisonofthepowerspectraldensityofdifferentstationsandtheairgunsignalrecognition,wefoundthatnoiselevelofstationswithrecognizableairgunsourcesignalsislowerthanthatofstationswithoutrecognizablesignals.Thelargestdifferenceofthepowerspectraldensityis40dB,andthesmallestis15dB.Finally,wefoundthatthefailuretorecognizethesignalofairgunsourcesatsomestationsisduetothenoiselevel.