Sound wave reverse time migration method based on Higdon third-order boundary condition

Abstract

The invention relates to a sound wave reverse time migration method based on a Higdon third-order boundary condition, and belongs to the field of seismic exploration migration imaging. The sound wave reverse time migration method has the specific steps of: step 1, carrying out continuation of a correct time wave field by taking seismic wavelets as correct time disturbance, saving central wave field values at the last two moments, and calculating and saving a wave field value in a boundary region based on the Higdon third-order boundary condition; step 2, carrying out continuation of a reverse time wave field by taking seismic records as reverse time disturbance, and reconstructing a central wave field value of the correct time wave field by utilizing the saved central wave field values and the wave field value of the boundary region; step 3, and multiplying a correct time wave field value and a reverse time wave field value at each point, regarding the result as an imaging value of the point, and adding the imaging values of all moments to obtain a final imaging value of the point. The sound wave reverse time migration method eliminates boundary reflection by utilizing the Higdon third-order boundary condition, achieves the reconstruction of the correct time wave field based on boundary storage of the boundary condition, can effectively reduce memory consumption of conventional reverse time migration, and has higher imaging precision.

Description

technical field [0001] The invention belongs to the field of seismic exploration migration imaging, in particular to an acoustic wave reverse time migration method based on Higdon's third-order boundary condition. Background technique [0002] The basic idea of ​​reverse time migration is to calculate the time extension of the forward wave field and the reverse time wave field through the numerical simulation of the wave equation, and perform imaging at the corresponding time. Because it is based on the two-way wave equation and is not limited by the dip angle, it is considered to be one of the best migration methods for imaging complex structures in current seismic exploration. Conventional acoustic reverse time migration mainly includes the following three steps: [0003] (1) Timing wavefield continuation, starting from the zero moment, using the acoustic wave equation finite difference numerical simulation method to simulate the seismic wave propagation process generated...

AI Technical Summary

Problems solved by technology

Commonly used wave field storage strategies are boundary storage technology based on PML and boundary storage technology based on random boundary conditions, but both methods have shortcomings

The boundary storage technology based on PML, due to the large amount of calculation of the PML boundary itself, will reduce the calculation efficiency of the wave field; the boundary storage technology based on random boundary conditions, due to the diffuse reflection at the boundary when the wave field is extended, so The central wave field restored by this method will contain more noise

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