Coherent value obtaining method and system of earthquake data amplitude spectrum

Abstract

The invention discloses a coherent value obtaining method and system of an earthquake data amplitude spectrum. The method comprises: step 1, obtaining a three-dimensional post-stack earthquake data body; step 2, calculating an effective frequency range for obtaining an amplitude spectrum; step 3, selecting a certain sampling point in the three-dimensional post-stack earthquake data body, and setting a slave data body which centers on a certain sampling point and includes a J-channel earthquake record; step 4,superposeing a window function on the J-channel earthquake record in the slave data body, and respectively performing Fourier transformation to obtain the amplitude spectrum of the J-channel earthquake record; step 5, obtaining and using the amplitude spectrum of the effective frequency range in the amplitude spectrum of the J-channel earthquake record to construct a J-dimensional covariance matrix, and calculating the characteristic roots of the J-dimensional covariance matrix, wherein the ratio of the maximum characteristic root in the characteristic roots to the sum of all the characteristic roots is a coherent value of a certain sampling point; and step 6, repeating step 3 to step 5, traversing each sampling point in the three-dimensional post-stack earthquake data body, and obtaining and recording the coherent value of each sampling point.

Description

technical field [0001] The invention relates to the technical field of geophysical exploration, in particular to a method and a system for obtaining coherent values ​​of amplitude spectra of seismic data. Background technique [0002] In oil and gas exploration, coherent technology is widely used. The use of coherent technology can highlight the characteristics of discontinuity and suppressed continuity of seismic data. Its slices are more clear and intuitive than conventional data volume slices, and various geological phenomena can be displayed more clearly. Therefore, it is widely used in oil and gas exploration. Geological phenomena such as structures, sedimentary reservoirs and special geological bodies can be clearly revealed through section display, horizontal slice and three-dimensional display of coherent bodies. [0003] Since the coherent algorithm was first proposed by Bahorich et al. in 1995, three generations of algorithms have appeared. The first generation i...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the disadvantages of the above algorithm, such as the influence of dip angle, large amount of calculation, and low efficiency, the present invention utilizes the characteristic that the amplitude spectrum does not contain formation dip angle information, and proposes a coherent method using the amplitude spectrum obtained by short-time Fourier transform as input data. Volume algorithm, not only can eliminate the influence of inclination but also has higher calculation efficiency

Images