Method and device for quickly identifying seismic phase by using controllable vibrating source to excite seismic signals

Abstract

The invention provides a method and device for quickly identifying a seismic phase by using a controllable vibrating source to excite seismic signals. Fractional order Fourier transform is used to fastly identify the seismic phase of the linear frequency modulation seismic signals excited by the controllable vibrating source, linear properties of traditional Fourier transform are inherited, interference of cross terms in time-frequency analysis can be suppressed, time-frequency distribution characteristics of the linear frequency modulation seismic signals excited by the controllable vibratingsource can be improved, a pulse function is taken as an analysis object, a signal-to-noise ratio of the seismic phase can be improved, and a reliable data foundation can be provided for geological interpretation when the seismic phase is identified.

Description

technical field [0001] The invention relates to the field of seismic exploration, in particular to a method and a device for quickly identifying seismic phases by using a vibrator to excite seismic signals. Background technique [0002] In seismic exploration, observation technology plays a vital role. The precision vibrator can generate frequency-controllable elastic waves. Due to the high frequency accuracy, the geophone can receive signals in a narrow bandwidth; through the precise control of the waveform phase, the signal-to-noise ratio is further improved by using signal superposition technology to achieve a relatively high frequency. Low power for long-distance seismic data acquisition. The precision vibrator device can operate continuously and stably for a long time. Compared with artificial sources such as blasting and hammering, it has great application prospects. [0003] The seismic signal excited by the vibroseis is a linear frequency modulation (LFM) signal, i...

AI Technical Summary

Problems solved by technology

For example, some nonlinear transformations will bring serious cross-term interference, which seriously interferes with people's interpretation of the time-frequency characteristics of the signal; in order to suppress the cross-term, the time-frequency resolution has to be sacrificed, and the calculation is huge

In addition, the research on the above method is mainly applicable to nonlinear and non-stationary signals, rather than chirp signals generated by vibrators

In the research on the signals excited by vibroseis, Yang Wei et al. (2013) carried out four methods of processing and analysis, including cross-correlation, short-term correlation, coherence and deconvolution, and analyzed them from the repeatability, travel time profile, spectrum characteristics and The processing results were compared and analyzed in terms of signal-to-noise ratio, etc., and the ability of mathematical and physical methods to identify seismic signals excited by vibrators was preliminarily studied. However, various methods have certain limitations and cannot well meet the needs of surveying.

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