Finite difference migration method based on rational Chebyshev approximation optimizing coefficient

Abstract

The prospecting degree of the oil-gas reservoir with a complicated structure is continuously increased at present, a finite difference prestack depth migration method becomes a most effective means for imaging of a complicated structure region due to high imaging precision, but the finite difference prestack depth migration method has a steep dip angle imaging problem. In order to solve the steepdip angle imaging problem, the invention provides a method for solving the optimizing coefficient of a finite difference frequency-dispersion equation by using rational Chebyshev approximation so as to improve the finite difference prestack depth migration. According to the method disclosed by the invention, imaging of a steep dip structure and a region with severe lateral velocity change is realized.

Description

technical field [0001] The invention relates to the field of seismic data processing, in particular to the pre-stack depth migration of the finite difference method. Background technique [0002] With the further deepening of oil and gas exploration, the focus of its exploration has shifted to areas with complex structures or drastic velocity changes, making conventional migration processing unable to obtain accurate imaging of subsurface structures. Prestack depth migration can be adapted to accurate imaging in areas with complex structures or dramatic velocity changes, and is an effective method for accurate imaging in areas with complex structures. [0003] Depth migration technology began in the 1970s, had great development in theory and methods in the 1980s, and was widely used in the 1990s. At present, prestack depth migration is mainly based on the Kirchhoff integral method and wave equation method. Since the kirchhoff integration method makes a high-frequency appro...

AI Technical Summary

Problems solved by technology

Although the phase shift method has high computational efficiency, it is not suitable for media with sharply changing lateral velocities; although the step-by-step Fourier has the highest computational efficiency, it has the lowest imaging accuracy for complex structures; although the Fourier finite difference method has high imaging accuracy for complex structures, its calculation The efficiency is the lowest; although the generalized screen method has a good imaging effect on media with severe lateral velocity changes, it needs to reduce the continuation step size to ensure the stability of the algorithm, thus increasing the amount of calculation

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