Pre-stack time migration imaging method based on equivalent offset distance

Abstract

The invention discloses a pre-stack time migration imaging method based on an equivalent offset distance. The method comprises the following steps: extracting each CSP gather and obtaining root-mean-square speed distribution, performing an equivalent offset distance migration on each CSP gather on the basis of a root-mean-square speed at a position of a corresponding target scattering point to obtain equivalent migration gathers of migration imaging results containing the target scattering points and nearby scattering points, extracting roads, which have the same horizontal plane projection coordinates as the target scattering points, from the equivalent migration gathers to form common equivalent point gathers, and horizontally stacking the common equivalent point gathers of the target scattering points to obtain image points, formed by near scattered wave energy and remote scattered wave energy, of all the scattering points. Scattered wave energy at positions of the common scattering point gathers and energy of remote scattering point gathers are used, so the final imaging effect noise is small, and imaging is relatively real.

Description

technical field [0001] The invention relates to the technical field of seismic exploration, in particular to a pre-stack time migration imaging method based on equivalent offset. Background technique [0002] The equivalent offset (EO) method converts the double square root travel time formula of seismic scattered waves into a single square root formula based on the scattered wave theory and the principle of Kirchhoff prestack time migration. . Applying this time-distance relationship can map seismic traces within a given range of equivalent offsets to a new gather, that is, the equivalent offset unit of the Common Scattering Point (CSP) gather. The CSP gather gathers the scattering energy distributed along the hyperbolic path on the common scattering point gather, and the common scattering point gather has a higher coverage number and a larger offset range. [0003] The equivalent offset migration (EOM) method has the advantages of stronger noise immunity and adaptability...

AI Technical Summary

Problems solved by technology

[0004] However, the EOM method only utilizes part of the scattered wave energy at the position where the common scattering point gather is located, and discards some useful energy of distant scattering points.

This leads to incomplete convergence of imaging results, high noise, and unclear imaging interface of underground structures.

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