Full waveform inversion method and device

Abstract

The invention provides a full waveform inversion method and device. The method comprises the following steps of using an optimal inversion frequency group to carry out forward modeling on a formationvelocity model; using original single shot data and the forward modeling result of the formation velocity model to generate a ground surface receiving wave field; using a spectral continuation methodto generate the basis function of the original single shot data; using the basis function and the ground surface receiving wave field to recover the low frequency data of the original single shot data; generating the frequency domain gradient field of the preset number of single shot data sets according to the low frequency data; inverting the formation velocity model by using the frequency domaingradient field and an optimized step size; and executing an iterative operation, and using another optimal inversion frequency group to carry out forward modeling on the inversed formation velocity model to obtain the final inversion result of the formation velocity model. The low frequency data of seismic data can be recovered and the low frequency data can be used to obtain accurate full waveform inversion result.

Description

technical field [0001] The invention relates to the field of petroleum exploration, especially seismic data processing, and in particular to a full waveform inversion method and device. Background technique [0002] With the deepening of seismic exploration, the geological problems faced are becoming more and more complex; the short-wavelength velocity can not only improve the accuracy of depth domain migration, but also can be used to indicate small inhomogeneous bodies, thus indicating sand bodies, fractures, caves, and faults. Geological targets with different petrophysical properties, such as belts and overpressure zones. The full waveform inversion method can invert short-wavelength velocity changes. It can be applied to short-wavelength modeling of medium-shallow velocity, and can also be used in combination with demigration for reflection wave inversion. It is the current international petroleum seismic exploration data processing method methods are being intensively...

AI Technical Summary

Problems solved by technology

Full waveform inversion has obvious effects in constructing high-resolution velocity models, but the lack of low-frequency information increases the dependence on high-precision initial models. Inaccurate initial models are likely to cause cycle jumps in the absence of low frequencies, which is not very good tectonic background velocity, so that the full waveform inversion can not get good results

At the same time, when the actual wavelet is missing, the amplitude information is difficult to apply, the full waveform inversion based on waveform subtraction is difficult to correct the velocity, and the full waveform inversion based on the travel time residual will lose part of the amplitude information. A method of full waveform inversion capable of recovering low-frequency information from seismic data

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