Vibroseis pseudo random scanning signal generating method

Abstract

The invention is a seismic acquisition vibroseis pseudo random scanning signal generating method in geophysical exploration. The method comprises the following steps: a Gold sequence code is generated according to the length of to-be-generated Num groups of vibroseis pseudo random scanning signals to obtain a target amplitude spectrum; windowing processing is performed on cross-correlation and autocorrelation of the Num groups of amplitude spectrum shaping signals in a time domain to obtain Num groups of pressed reconstruction signals; the maximum value of cross-correlation between each Num group of high-cut filter signals on the same time point position is divided by the minimum value of autocorrelation of each group of signals at the time zero to obtain the maximum relative cross-correlation value of the Num groups of high-cut filter signals; and iterative modification is performed to generate the final Num groups of vibroseis pseudo random scanning signals. The method of the invention enables the cross-correlation effect between the groups of pseudo random signals to be weak, thereby inhibiting adjacent gun interference in the efficient acquisition process, and improving the separation quality of shot records. The instantaneous frequency energy does not vary monotonically with time, which can greatly reduce the risk of resonance of surrounding buildings in the vibroseis construction process.

Description

technical field [0001] The invention relates to a vibrator technology for seismic acquisition in geophysical prospecting, and relates to a method for generating pseudo-random scanning signals of a vibrator. Background technique [0002] Vibroseis technology is to use geophones to receive seismic waves excited by vibroseis in land seismic exploration to obtain underground structure information. Compared with explosive vibrators, vibrators have many advantages, such as safety, environmental protection, reusability, known and controllable excitation signals, etc., so they are more and more used in land seismic exploration. [0003] The conventional linear scanning signal is still the most widely used scanning method in vibroseis exploration. The linear scanning signal has many advantages, such as the average energy distribution, the energy occupied by the unit frequency is the same, and there is no frequency filtering effect on the signal components within the scanning frequen...

AI Technical Summary

Problems solved by technology

When the conventional linear scanning signal is used as the source signal for excitation, the related shot set records obtained by cross-correlation between the scanning signal and the vibration signal will have strong adjacent shot interference, so it is impossible to conduct on-site quality control on it, and the follow-up Higher requirements are put forward for the suppression of adjacent shot interference in seismic data processing

However, using the above-mentioned method of directly using m-sequences to generate pseudo-random vibroseis scanning signals, it is also impossible to generate several groups of scanning sequences with weak correlation characteristics, so it is still unable to directly suppress the interference of adjacent shots caused by high-efficiency acquisition

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