Study on deep structure of the residual basin of the Yellow Sea using VTI medium Marine CSEM and MT data inversion method
Due to the complexity of stratigraphic structure and deep geological structure,the Yellow Sea residual basin has always been a research focus of Marine geosciences in China.Although lots of geophysical investigations have been carried out,the quality of deep seismic data in this area has been greatly affected due to the shielding effect of high speed carbonate strata on seismic waves.The marine electromagnetic method is not affected by the high speed shielding layer,which is beneficial to obtain the deep structure information inside and below the high speed shielding layer.It is well known that controlled source electromagnetic(CSEM)and magnetotelluric(MT)data provide complementary information about the subsurface resistivity distribution;hence,it is useful to derive earth resistivity models that simultaneously and consistently fit both data sets.In this paper,a joint inversion method for Marine CSEM and MT data in layered vertical anisotropic(VTI)media is proposed based on product objective function.The method adaptively adjusts the weights of CSEM and MT data according to the data fitting during the inversion.Based on the geological and geophysical data of the Yellow Sea,we established a shallow water geoelectric model.The synthetic data was retrieved and analyzed combining with the high noise background characteristics of the shallow water.The inverse calculation examples of the synthetic data of the theoretical model and the measured data in the South Yellow Sea show that the proposed method can reconstruct the anisotropic resistivity of shallow sedimentary layers,the resistivity of basement layer,the burial depth and the vertical resistivity of thin reservoir layer more accurately.The joint inversion of marine CSEM and MT data can improve the resolution of anisotropic resistivity of seabed strata.
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万方数据
