Converted-wave curved ray amplitude-reserved anisotropic pre-stack time offset time method

Abstract

The invention provides a converted-wave curved ray amplitude-reserved anisotropic pre-stack time offset time method, belonging to the geophysical exploration field. The method comprises steps of inputting three-dimensional converted-wave pre-stack gather record and a converted-wave anisotropic velocity body, beginning imaging, calculating longitudinal wave offset speed and transverse wave speed offset speed at the imaging sample point in series, calculating longitudinal wave anisotropic parameters and transverse wave anisotropic parameters, calculating longitudinal wave travel time and transverse wave travel time, calculating converted wave anisotropic travel time, calculating a cosine of a ray angle of incidence, calculating a cosine of a ray angle of emergence, calculating geometric diffusion term, calculating amplitude weighting coefficient, finishing amplitude preserving migration processing, and performing imaging by performing the above processing on all imaging points.

Description

technical field [0001] The invention belongs to the field of geophysical exploration, in particular to a converted wave bending ray amplitude-preserving anisotropic pre-stack time migration method. Background technique [0002] When the surface is excited by a vertical source to generate an artificial seismic wave field, part of the energy of the longitudinal wave propagates downward and reaches the underground reflection interface. Equation, can also be converted into a shear wave (S), propagating in the direction of the ground. Recording and receiving with three-component geophones on the surface can obtain multi-component seismic data of longitudinal wave (PP) and converted wave (PS). The PS wave pre-stack time migration (pre-stack time migration) imaging method can solve the problem of subsurface structural imaging of special reservoirs. For example, the serious absorption and attenuation of the PP wave under the gas cloud causes the imaging of the reservoir structure t...

AI Technical Summary

Problems solved by technology

[0017] However, applying this hyperbolic travel time calculation formula (1) to process Kirchhoff pre-stack time migration will lead to over-biasing of large offset data migration (see figure 1 box)

Using this simple distance weighting function formula (3) to perform offset amplitude correction will also cause overweighting of gathers with large offset distances, which is equivalent to no amplitude weighted correction (see figure 2 box)

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