Research On Full Waveform Inversion Method Based On Global Correlation And Wave Field Envelope

As the difficulty of oil and gas exploration increases,the innovation of seismic exploration is extremely urgent.Full waveform inversion technology has become a research hotspot in the field of seismic exploration due to its ability of high-resolution velocity modeling and multiparameter inversion.But at the same time,its strong nonlinearity,expensive calculation cost and extreme dependence on the initial model are still not solved.Some problems are studied in this paper,and the contents are summarized as follows:High order staggered grid finite difference method was used to solve the acoustic wave equation,and CPML boundary and region decomposition parallel strategy was used to realize the high efficiency and high precision numerical simulation of seismic wave field.The basic mathematical theory of full waveform inversion is introduced and deduced,and the full waveform inversion is realized by numerical experiments to verify its capability of highprecision modeling.Different objective functions of the full waveform inversion and flexible inversion strategies are used to calculate the seismic data witch has different characteristics.In this paper,multi-scale full waveform inversion is implemented,and numerical experiment results show that the strategy can effectively alleviate the non-linearity of full waveform inversion,avoid the "cycle-skipping" phenomenon,and greatly improve the inversion accuracy.In view of the source wavelet estimation in the inversion problem,this paper USES the global correlation objective function to carry out the full-waveform inversion,and compares with the conventional full-waveform inversion results.The global correlation objective function can perform the inversion results with more reference under the condition of the source wavelet error.In view of the low frequency component in seismic data,the objective function of logarithmic envelope structure is used for envelope inversion,and the idea of multiscale inversion is used for reference.