Seismic wavefield modeling based on close-loop one-way propagation operator
The strong impedance interfaces of the sea surface and seabed cause significant multiples and ghost wavefield in marine seismic data.The finite-difference method of the two-way wave equation widely used in seismic data modeling cannot separate multiples and ghost wavefield of different orders.That cannot perfectly combine with the migration and parameters inversion process.Traditional methods limit the popularization and application of multiples suppression and migration methods.In this study,the marine seismic wavefield modeling method based on a close-loop one-way propagation operator was derived and the forward modeling equation of ghost wavefield was established.Firstly,one-way propagation operator is derived,and the propagation model of traditional primary reflections is given.Secondly,propagation models of surface-and internal-related multiples are obtained by loading the last round of reflected data at different depths and using closed-loop iterative calculations.The proposed method can achieve multiples simulations and separation of different orders.Then,the ghost waves propagation model is derived by placing the source below the water surface and changing the loading order of seismic sources.Surface-,internal-related multiples,and ghost wavefield of the lenticle model have been accurately simulated and analyzed.The Marmousi model was implemented to compare the accuracy of proposed mothed and finite-difference method,in which the synthetic data of different methods show similar results.The proposed method can reasonably and effectively obtain multiples and ghost wavefield of desired orders,which can be well combined with subsequent migration and inversion processes to improve imaging illumination and resolution.
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