A full waveform inversion method and device with adjustable amplitude and phase information

Abstract

The invention discloses a full waveform inversion method and device with adjustable amplitude and phase information. Multiple single-frequency coded signals are simultaneously excited as seismic sources; the first-order velocity-stress acoustic wave equation is used to complete in one forward simulation For the wave field simulation of multiple source wavelets, the phase-sensitive detection method is used to perform wave field decoupling calculations on the forward and backward wave fields, and obtain gradient results without crosstalk. The gradient calculation of the velocity field model parameters in the objective function In the expression calculation, different calculation expressions are used in different inversion stages, that is, phase information inversion is mainly used in the early stage of inversion, and full waveform inversion is used in the middle and later stages of inversion, which can weaken the inversion. The dependence of inversion on the initial model; by using the strategy of combining phase inversion and full waveform inversion, the complexity of the objective function can be reduced, thereby reducing the multi-solution in inversion, and finally achieving high-precision inversion.

Description

technical field [0001] The invention relates to a full waveform inversion method and device with adjustable amplitude and phase information, and belongs to the technical field of seismic exploration speed modeling. Background technique [0002] As my country's oil exploration shifts to deep and ultra-deep layers, the problem of high-precision imaging of high-steep and complex structures in deep target layers has become an imminent bottleneck restricting my country's oil exploration and development. Velocity modeling is the soul of complex structural imaging, and traditional velocity modeling techniques such as velocity tomography inversion have achieved great success in the past few decades, but they can no longer meet the needs of high-resolution seismic imaging. Therefore, it is urgent to develop a new generation of velocity modeling technology to meet the needs of imaging complex structures. [0003] At present, full waveform inversion (Full Waveform Inversion, FWI) is r...

AI Technical Summary

Problems solved by technology

However, the low computational efficiency is the main factor that restricts the large-scale calculation and actual data processing of full waveform inversion. An existing solution is to use the source coding strategy. The idea is to form many single shots into A super seismic source, thereby reducing the number of wavefield simulations

One of the widely used method is the simultaneous source full waveform inversion method based on frequency selection, which can obtain inversion results without crosstalk. The model is relatively sensitive, and the use of full wave field information matching can easily cause the full waveform inversion to fall into a local minimum, so it is very necessary to carry out data subset or wave field attribute inversion

Since the amplitude information is more sensitive to the initial model than the phase information, when the initial model is inaccurate, using the full waveform inversion directly may lead to inaccurate update of the low wavenumber of the full waveform inversion, resulting in incorrect interface position of the high wavenumber update , reducing the accuracy of the inversion

[0004] Therefore, how to provide a new simultaneous source inversion method that can overcome the problem of low inversion accuracy existing in the prior art is a technical problem that those skilled in the art need to solve urgently

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