Bayesian Markov chain Monte Carlo inversion for anisotropy of PP- and PS-wave in weakly anisotropic and heterogeneous media

(整期优先)网络出版时间:2017-01-11
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Asinglesetofverticallyalignedcracksembeddedinapurelyisotropicbackgroundmaybeconsideredasalong-wavelengtheffectivetransverselyisotropy(HTI)mediumwithahorizontalsymmetryaxis.Thecrack-inducedHTIanisotropycanbecharacterizedbytheweaklyanisotropicparametersintroducedbyThomsen.TheseismicscatteringtheorycanbeutilizedfortheinversionfortheanisotropicparametersinweaklyanisotropicandheterogeneousHTImedia.Basedontheseismicscatteringtheory,wefirstderivedthelinearizedPP-andPS-wavereflectioncoefficientsintermsofP-andS-waveimpedances,densityaswellasthreeanisotropicparametersinHTImedia.Then,weproposedanovelBayesianMarkovchainMonteCarloinversionmethodofPP-andPSwaveforsixelasticandanisotropicparametersdirectly.Testsonsyntheticazimuthalseismicdatacontaminatedbyrandomerrorsdemonstratedthatthismethodappearsmoreaccurate,anti-noiseandstableowingtotheusageoftheconstrainedPS-wavecomparedwiththestandardsinversionschemetakingonlythePP-waveintoaccount.