Earthquake beam forming method based on high-order cosine amplitude weighting
A technology of amplitude weighting and seismic wave, applied in the direction of seismic signal processing, etc., can solve the problems of flexible control of directional seismic wave field and inflexible control of beam shape
Inactive Publication Date: 2013-10-02
JILIN UNIV
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The disadvantage of the equal-amplitude weighting method is that although the beam direction is controllable, the beam shape cannot be flexibly controlled, so the energy distribution of the directional seismic wave field cannot be flexibly controlled according to the geological target situation and the parameters of the seismic observation system, so as to better improve the signal-to-noise reception arrangement than the purpose
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Embodiment 1
[0062] The 40-shot single-shot records generated by matlab simulation apply the seismic beamforming method based on high-order cosine amplitude weighting. Each single-shot record contains strong background noise with an intensity of 22dB, and the depth of the first radioactive layer is h 1 =200m, the average velocity above the first reflection layer is 800m / s, the reflection layer is a horizontal layer, the direct arrival wave velocity is 800m / s, and the minimum offset x 1 =20m, maximum offset x 2 =670m, there are 65 geophones in total, the track spacing is 10m, the running point distance D=2m, the stratum is a horizontal stratum, that is, the dip angle α=0°, the vibroseis is used as the excitation source, and the vibroseis is used to excite the frequency sweep signal. The start frequency is 50Hz, the stop frequency is 200Hz, the sweep time is 6s, and the sweep amplitude is 1.
[0063] a. Input matlab-simulated 40-shot single-shot records containing strong background noise wi...
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The invention relates to an earthquake beam forming method based on the high-order cosine amplitude weighting, which comprises the following steps: firstly, designing the directional earthquake wave direction and beam forming time delay control parameters as per observed parameters of a target layer and an observing system; secondly, computing amplitude weight factors corresponding to various single-shot records as per cosine weighting distribution function; finally, obtaining directional earthquake wave data with high signal-to-noise ratio in virtue of the time delay and weighting superposition beam forming method. According to the invention, the signal-to-noise ratio of earthquake data is improved; the method is particularly applicable in the situations that the background noise is stronger, the main beam adopting an equiamplitude weighting manner is narrower, the coverage area is limited and the integral signal-to-noise ratio of earthquake data is lower; the integral signal-to-noise ratio of earthquake data is improved as the width of the main beam adopting the cosine weighting manner is greater than that of the main beam adopting the equiamplitude weighting manner when the earthquake beam is formed through adopting the same single-shot records. The single-shot earthquake data adopting the cosine amplitude weighting manner and the single-shot earthquake data adopting the equiamplitude weighting manner are shown in the attached maps, so that through comparison, the earthquake beam forming method has the advantages that the improved earthquake data quality effect is obvious, and the signal-to-noise ratio of the earthquake data is effectively improved.
Description
Technical field: [0001] The invention relates to a seismic exploration data preprocessing method, in particular, a seismic beam forming method based on high-order cosine amplitude weighting is adopted when using the directional seismic beam principle to perform seismic data preprocessing under strong background noise. Background technique: [0002] At present, there are mainly two methods for realizing directional seismic beams, one is to directly excite directional seismic beams by using a phase-controlled source; the other is a time-domain seismic beamforming method based on receiving arrays. The time-domain seismic beamforming method based on the receiving array can adopt both equal-amplitude weighting and non-equal-amplitude weighting. The equal-amplitude weighting method can control the beam direction by controlling the phase or delay parameters. Through reasonable beam direction design, the seismic wave can be focused, so that the seismic receiving array mainly receive...
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IPC IPC(8): G01V1/28
Inventor 姜弢宋健徐学纯林君葛利华贾海青
Owner JILIN UNIV