Organicreefs,thetargetsofdeep-waterpetroleumexploration,developedwidelyinXishaarea.However,thereareconcealedigneousrocksundersea,towhichorganicrockshavenearlyequalwaveimpedance.Sotheigneousrockshavebecomeinterferenceforfutureexplorationbyhavingsimilarseismicreflectioncharacteristics.Yet,thedensityandmagnetismoforganicreefsareverydifferentfromigneousrocks.Ithasobviousadvantagestoidentifyorganicreefsandigneousrocksbygravityandmagneticdata.Atfirst,frequencydecompositionwasappliedtothefree-airgravityanomalyinXishaareatoobtainthe2Dsubpisionofthegravityanomalyandmagneticanomalyintheverticaldirection.Thus,thedistributionofigneousrocksinthehorizontaldirectioncanbeacquiredaccordingtohigh-frequencyfield,low-frequencyfield,anditsphysicalproperties.Then,3Dforwardmodelingofgravitationalfieldwascarriedouttoestablishthedensitymodelofthisareabyreferencetophysicalpropertiesofrocksbasedonformerresearches.Furthermore,3Dinversionofgravityanomalybygeneticalgorithmmethodofthegraphicprocessingunit(GPU)parallelprocessinginXishatargetareawasapplied,and3Ddensitystructureofthisareawasobtained.Bythisway,wecanconfinetheigneousrockstothecertaindepthaccordingtothedensityoftheigneousrocks.Thefrequencydecompositionand3DinversionofgravityanomalybygeneticalgorithmmethodoftheGPUparallelprocessingprovedtobeausefulmethodforrecognizingigneousrockstoits3Dgeologicalposition.Soorganicreefsandigneousrockscanbeidentified,whichprovideaprescientinformationforfurtherexploration.
