Velocity analysis method for Rayleigh surface waves

Abstract

The invention discloses a velocity analysis method for Rayleigh surface waves. The velocity analysis method comprises the following steps: 1, reading a single-shot Rayleigh surface wave seismic record (containing m paths, each path has n sampling points, and the time sampling rate is delta t) to a two-dimensional array g; 2, carrying out two-dimensional Fourier transform on the g so as to obtain a f-k spectrum; 3, establishing a relation among penetration depth (h), velocity (v), frequency (f), wave number (k), wavelength (Lambda) and poisson ratio (Sigma); 4, according to the relation among the penetration depth (h), velocity (v), frequency (f), wave number (k), wavelength (Lambda) and poisson ratio (Sigma) of Rayleigh surface waves, mapping energy corresponding to (k, f) coordinates in the f-k spectrum to a position corresponding to (v, h) coordinates in a h-v spectrum, and selecting a coordinate range outputted by the h-v spectrum and carrying out figure formation; and 5, based on the h-v spectrum, sequentially picking up strong energy groups in the h-v spectrum from shallow to deep, and extracting corresponding (v, h) coordinate values. The method disclosed by the invention has the advantages of being simple and convenient in information extraction and high in precision.

Description

technical field [0001] The invention belongs to the technical field of seismic Rayleigh surface wave velocity parameter extraction, in particular to an analysis method for Rayleigh surface wave velocity. Background technique [0002] Rayleigh surface wave is a very effective seismic exploration method in the study of the earth's internal structure and various engineering exploration problems near the surface, especially in the acquisition of near-surface strata structure and attribute characteristics. Due to the dispersion characteristics of Rayleigh waves, the existing methods are mainly based on the f-k The Rayleigh surface wave dispersion curve can be extracted by using the spectrum, and the corresponding formation structure, structure and other information can be extracted according to the characteristics of the dispersion curve. On the other hand, the shear wave velocity is retrieved by extracting the dispersion curve of the Rayleigh surface wave, and then the formatio...

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Problems solved by technology

In fact, the hidden information in Rayleigh surface waves is very rich, and the existing methods have two defects: on the one hand, the information extracted after processing is limited, and the geological information reflected is too simple and not intuitive enough to directly solve actual geological problems On the other hand, the concept of Rayleigh surface wave penetration depth is relatively vague, and the relationship between the hidden geological information and depth of Rayleigh surface waves cannot be directly established, which affects the ability of Rayleigh surface waves to solve practical geological problems.

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