Crack detection method based on Alford rotation

Abstract

The invention discloses a crack detection method based on Alford rotation. The method includes: step 1, obtaining radial components and tangential components of multi-component seismic data, wherein the radial component is a component along the direction connecting the shot point and the receiver point, and the tangential component is a component perpendicular to the direction along the line The component of the direction of the line between the shot point and the receiver point; step 2, based on the radial component and the tangential component, using Alford rotation to scan according to the rotation angle and time difference to obtain the correlation coefficient spectrum of the fast and slow waves; step 3, based on the The correlation spectrum determines the development information of subsurface fractures. The application of the present invention can effectively solve the problem of inaccurate prediction in the case of large angle intervals in conventional fracture prediction, and has positive effects on subsequent elimination of anisotropic influence and improvement of imaging quality.

Description

Technical field [0001] The invention relates to the field of petroleum exploration, and more specifically, to a crack detection method based on Alford rotation. Background technique [0002] In multi-wave seismic exploration, the phenomenon of shear wave splitting in fractured media by converted waves can be used to predict fractures more accurately, and finally obtain fracture development azimuth and density information. Using converted waves to predict fractures is usually divided into two steps. The first is to determine the azimuth information of fracture development, and on this basis, the fast and slow waves are separated; then the time difference between the fast and slow waves is analyzed, which corresponds to the strength of fracture development. In the aspect of obtaining the azimuth angle of fracture development, the more common method is the converted wave radial / tangential (R / T) energy ratio method. When the seismic data is rotated to the maximum R / T energy ratio, i...

AI Technical Summary

Problems solved by technology

However, in the implementation process of this patent, the traditional triangular rotation method is used to scan the angle, which is likely to cause instability in the actual calculation process due to the existence of noise; The solution will be unstable due to the difference in energy of the fast and slow waves themselves

Therefore, the above methods are unsatisfactory in the actual application of multi-wave fracture prediction

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