Method for eliminating imaging error of undulating the earth's surface

Abstract

The invention is a method for eliminating image error of relief land surface by simple harmonic wave fitting technique, relating to geophysical seismic data exploration, collecting seismic data of an observing system; extracting the seismic data to be processed by wave field extrapolation into a common shot gather or a common detector gather for arranging to obtain a corresponding known wave field; dissecting the region between relief land surface and extrapolation destination curve by extrapolation grid; converting the original wave field data from time domain to frequency domain; using the simple harmonic wave fitting method to calculate extrapolation operator of the dissecting grid; making wave field extrapolation calculation on the seismic data by the extrapolation operator; converting the wave field data extrapolated to the destination curve from frequency domain to time domain and imaging. The invention has small error, low interference and high accuracy.

Description

technical field [0001] The invention relates to a processing method for seismic data of geophysical exploration, in particular to a method for eliminating imaging errors of undulating surface by using simple harmonic wave fitting technology. Background technique [0002] The undulating surface is a difficult problem in oil and gas seismic exploration. When the surface is violently undulating, conventional static correction methods (static time shift) are difficult to completely eliminate the errors in imaging, which will adversely affect velocity analysis and stacking imaging. Similarly, when the (static time shift) correction amount is large, there is still a similar situation in datum-corrected post-stack data. The solution to this problem is usually to replace the static time shift with wave field extrapolation, so that waves with different inclination angles can be correctly homing, so that the subsequent processing steps can achieve good imaging results. Wave field ext...

AI Technical Summary

Problems solved by technology

There are two main defects in these algorithms when extrapolating non-planar wave fields: First, when extrapolating non-planar wave fields, they have to perform non-fluctuating approximation processing on the wave field, which is actually a disturbance to the original wave field , sometimes causing large imaging errors; secondly, in many areas, due to the influence of surface conditions, the distribution of observation points on the survey line is irregular, and the difference method and phase shift method require that the sample points must be equally spaced. For this reason, Sometimes a large number of zero data traces are interpolated in the survey line, causing interference in the wavefield extrapolation process

In addition, the difference method cannot maintain high accuracy with the step size change, and the phase shift method has poor adaptability to speed changes

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