Full-waveform inversion method based on dynamic random seismic source coding

Abstract

The invention discloses a full-waveform inversion method based on dynamic random seismic source coding. The invention discloses a dynamic random seismic source coding new strategy, belongs to the field of geophysics, and provides a dynamic random seismic source coding new strategy by randomly selecting four aspects of amplitude, phase, polarity and shot point position of a seismic source, which comprises the following main steps of: randomly selecting actual shots and time coding sequence convolution, and synthesizing a super shot profile; calculating a super shot residual error, a gradient direction and an optimal step length; inversion iteration is carried out, and target parameters are updated; and judging whether an inversion termination condition is met or not. Crosstalk noise betweenshots is avoided, and the inversion efficiency is greatly improved on the premise that the inversion precision is not affected. The new dynamic random seismic source coding strategy is introduced into the solution of the L-BFGS algorithm of the variable density acoustic wave equation full waveform inversion, the crosstalk influence of the medium density and the acoustic wave speed during the synchronous inversion is effectively reduced, and the full waveform inversion speed is improved.

Description

technical field [0001] The invention belongs to the field of geophysics, and in particular relates to a full waveform inversion method based on dynamic random seismic source coding. Background technique [0002] In the conventional full waveform inversion of the acoustic wave equation, it is usually assumed that the medium density is a known constant value, and only the acoustic velocity is inverted. But in fact, velocity and density play an important role in the quantitative interpretation of seismic data and in oil and gas interpretation, in which density information can predict reservoir fluid saturation. Therefore, obtaining reliable density parameters in full waveform inversion has become an urgent need. With the improvement of large-scale scientific computing capabilities, multi-parameter FWI has gradually become possible, and has quickly become an important research direction of FWI. Seismic data imaging research shows that multi-parameter full waveform inversion ha...

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Problems solved by technology

[0004] During the full-waveform dual-parameter inversion process of the variable-density acoustic wave equation, due to the inconsistency in the sensitivity of the perturbation of the two parameters of acoustic velocity and medium density to the inver

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