A method for exploration of geological conditions

Abstract

The invention discloses a geological condition exploration method. The geological condition exploration method comprises the steps of interpolating underground medium propagation velocity v(x) and a seismic record P(x, t) of the detector arrangement under a Cartesian coordinate system into an oblate spherical coordinate system, and acquiring an underground medium propagation velocity model v(xi) and a seismic record P(xi, t) of the detector arrangement under the oblate spherical coordinate system; transforming the seismic record P(xi, t) of the detector arrangement into a seismic record P (xi,omega) of the detector arrangement in the frequency domain through Fourier transform; continuing a single-frequency detector wave field P(xi|[xi]3, omega) downward by delta[xi]3 along the direction of a coordinate axis [xi]3 under the oblate spherical coordinate system, and acquiring a detector wave field P(xi|([xi]3+delta[xi]3), omega) at the ([xi]3+delta[xi]3) through velocity time shifting andfinite difference correction until the wave field is continued to the bottom [xi]3' of the model; continuing wave fields of different frequencies within a main frequency band range to the bottom [xi]3' of the model, superposing the offsets of all of the frequencies to obtain a superposed offset P(xi) of the oblate spherical coordinate system; and interpolating the superposed offset P(xi) to the Cartesian coordinate system to obtain a final offset section P(x). The imaging accuracy in geological condition exploration can be improved by adopting the method disclosed by the invention.

Description

technical field [0001] The invention relates to the field of geological condition exploration, in particular to a geological condition exploration method. Background technique [0002] In the process of geological condition exploration, the pre-stack depth migration based on the wave equation of wave field continuation is an effective means for migration imaging of complex structures. It uses wavefield continuation operators for migration imaging of seismic data. The wave field simulation method based on the one-way wave operator is an approximate method, which only considers the primary reflection wave and the diffraction wave of irregular points in the upgoing wave or downgoing wave during the seismic propagation process. The algorithm is simple and fast, and the obtained seismic records The signal-to-noise ratio is high. The wave field continuation operator based on the one-way wave equation is often used in the imaging of three-dimensional complex geological structures...

AI Technical Summary

Problems solved by technology

For this kind of steep angle structure, the angle between the wave propagation direction and the coordinate grid becomes larger in the Cartesian coordinate system, while the angle in the oblate spherical coordinate system is smaller than that in the Cartesian coordinate system, so it shows advantages. Therefore, the traditional The one-way wave operator in the Cartesian coordinate system cannot satisfy the high-precision imaging in the process of complex structure exploration.

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