Diffracted wave separating and imaging method based on reflected energy prediction

Abstract

The invention belongs to a geophysical exploration technology, and relates to a diffracted wave separating and imaging method based on reflected energy prediction. The diffracted wave separating and imaging method comprises the following steps of performing common-angle prestack depth migration on shot records to obtain a dip angle region common-imaging point gather after seismic data are acquired; predicting reflected wave from a full-wave-field common-imaging point gather according to significant difference of tracing patterns of the reflected waves and diffracted waves in the dig angle region common-imaging point gather; performing image similar matching on a predicted dip angle gather containing reflected energy only and a full-wave-field dip angle gather so as to remove reflected energy in a full wave field; using rest energy as diffracted response; and superposing the dip angle region common-imaging point gather which is pressed by a reflected common-phase axis along the dip angle direction to obtain an imaging result comprising diffracted energy mainly. The diffracted wave separating and imaging method based on the reflected energy prediction is a diffracted wave separating and imaging technology which is practical and is convenient to operate.

Description

technical field [0001] The invention relates to seismic data processing, which belongs to the migration imaging processing of seismic data, in particular to a diffraction imaging method based on reflection energy prediction which can improve the imaging resolution of a non-homogeneous diffraction target body. Background technique [0002] The most obvious and most valuable seismic response waveforms in seismic records mainly include reflected waves and diffracted waves. In a narrow sense, the formation conditions of reflected waves and diffracted waves mainly depend on the relationship between the scale of geological bodies and the wavelength of seismic waves: when the scale of geological bodies is much larger than the wavelength of seismic waves, reflected waves are generated; when the scale of geological bodies is equivalent to the wavelength of seismic waves Or when it is smaller than the wavelength of the seismic wave, a diffracted wave is generated. It can be seen that...

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Problems solved by technology

[0003] However, at this stage, traditional data processing or migration is often aimed at imaging and enhancing the reflected wave energy, and there are often the following unfavorable factors for imaging diffraction targets in some conventional processing procedures: 1) In NMO / DMO, In processes such as velocity analysis, events from outside the reflection layer are usually regarded as interference noise filtering; 2) Most conventional migration algorithms are aimed at imaging specular reflection information, for example, kirchhoff migration usually assumes high frequency or phase stability Approximately, even the traditional diffraction stacking is more inclined to image the reflected wave and ignore the scattering effect; 3) On the seismic section, the amplitude of the diffracted wave is usually weaker than the reflected wave by one to two orders of magnitude, even if it is offset , which is usually also masked by reflection information

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