Common scattering point pre-stack time migration imaging method based on time depth scanning

Abstract

The invention discloses a common scattering point pre-stack time migration imaging method based on time depth scanning. The method comprises the following steps: S1) reading in seismic input trace data; S2) determining a middle point coordinate of common scattering point gathers needing to be mapped, and starting from a middle point of the common scattering point gathers, selecting he increasinglyat the two sides with a step length delta h, and carrying out steps S3 and S4 in a loop manner till reaching maximum offset distance of the common scattering point gathers; S3) for any he, starting from the 0 moment, selecting time depth t0 increasingly with a step length delta t till maximum recording time t<max>R; S4) stacking values of sampling points of input traces at the t moment to recording points of recording traces, the equivalent offset distance of which is he, in the common scattering point gathers at the same moment; S5) repeating the steps S1)-S4) until all input traces are mapped to different common scattering point gathers respectively; and S6) finishing pre-stack time migration imaging through reflection wave seismic processing software. The method does not need an initial velocity model, can process low signal-to-noise-ratio data and realize reliable migration imaging.

Description

technical field [0001] The invention relates to a seismic data migration imaging method, in particular to a pre-stack time migration imaging method of common scattering points based on time-depth scanning. Background technique [0002] Migration imaging, also known as relocation processing, migration homing processing, imaging processing or delay processing, is the last and most important part of conventional seismic data processing. Seismic migration imaging profile is the imaging result of underground stratum and structure, and is one of the most important achievements of seismic exploration. The reliability and accuracy of migration imaging are directly related to the effectiveness of related exploration such as oil and gas resources, mineral resources and engineering. [0003] According to the nature of the input seismic data and the sequence of migration and stacking, migration imaging techniques can be divided into post-stack migration and pre-stack migration. The pos...

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Problems solved by technology

[0008] In summary, most of the existing migration imaging methods are highly dependent on velocity, and a reliable velocity model is the key to obtaining good imaging results. Although the conventional scattered wave prestack migration imaging method based on the equivalent The dependence of the velocity model is greatly reduced, but a suitable initial velocity model is a necessary condition in the process of mapping CSP gathers. Unreliable velocity will damage the imaging effect, so it often requires multiple iterations of velocity analysis and CSP gather mapping , which increases the amount of calculation and work. However, for seismic data with low signal-to-noise ratio, it is often difficult to obtain relatively accurate velocities, and the existing migration imaging methods are also difficult to apply

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