Effective speed extraction method based on ray density

Abstract

The invention provides an effective speed extraction method based on ray density. The effective speed extraction method based on ray density comprises the following steps: 1 loading an observation system; 2 picking up the first arrival wave time t of the seismic data; 3 calculating wave-front travel time of grid points; 4 calculating a ray path; 5 solving the ray density; 6 calculating an inversion speed; and 7 carrying out effective speed extraction. According to the effective speed extraction method based on the ray density, the density of ray penetration is mainly considered, the denser the ray is, the more accurate the speed is, the speed reaching a certain ray density is extracted, the method is used for pre-stack depth migration, and the effect is obvious; the process and parameter setting are simple, operation and implementation are easy, and the operation speed is high.

Description

technical field [0001] The invention relates to the field of oil and gas exploration seismic data processing, in particular to an effective velocity extraction method based on ray density. Background technique [0002] With the continuous development of pre-stack depth migration technology, the impact of shallow velocity on migration has been more and more recognized by everyone. Inaccurate shallow velocity will affect the imaging of deep seismic data. Conventional reflection tomography inversion The method is unable to obtain accurate shallow velocity due to too little near-offset data, so it is gradually developed to the current method of first arrival tomography to obtain shallow velocity. In the first arrival tomography method, the ray method is one of the important methods, but because the velocity obtained by this method is affected by factors such as seismic trace density and array length, only part of the velocity is accurate, and this part of the accurate velocity, ...

AI Technical Summary

Problems solved by technology

This patent calculates the travel time residual on the basis of extracting angle domain gathers, uses the reverse ray tracing method to obtain the sensitivity matrix, uses the least square method to obtain the slowness disturbance, and updates the velocity model. The basic data realized by this technology is Angle-domain gathers, shallow seismic data only have near-offset data, so the signal-to-noise ratio is low, and the reflection axis of the angle-domain gathers is also inaccurate, resulting in errors in the final inversion results

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