A first-arrival picking method for microseismic signals based on approximate negative entropy

A technology of microseismic and negative entropy, which is applied in seismic signal processing, seismology, geophysical measurement, etc., can solve the problem of picking up the first arrival time point of microseismic signals, and achieve accurate picking, fast speed and high accuracy Effect

Inactive Publication Date: 2018-07-13
JILIN UNIV
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  • Application Information

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Problems solved by technology

[0004] The present invention provides a micro-seismic signal first-arrival picking method based on approximate negative entropy to solve the problem of difficulty in picking the first-arrival time point of the micro-seismic signal under the condition of low signal-to-noise ratio

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  • A first-arrival picking method for microseismic signals based on approximate negative entropy
  • A first-arrival picking method for microseismic signals based on approximate negative entropy
  • A first-arrival picking method for microseismic signals based on approximate negative entropy

Examples

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experiment example 1

[0077] Experimental example 1 synthesis record

[0078] Simulate and generate a synthetic microseismic record of 100 channels with a sampling frequency of 1000 Hz, each channel has 512 sampling points, and the main frequency of the effective signal is 300 Hz. Gaussian white noise of different intensities is added to the pure seismic record, and the signal-to-noise ratio is obtained from -1dB Synthetic noisy microseismic records to -12dB. In order to verify the influence of SNR on the performance of the first break picking method, firstly, a single trace of noisy microseismic data with a first arrival time of 160 ms is selected from the noisy record with a SNR of -3 dB, as shown in Fig. 2(a) Show. The AIC method, STA / LTA method and approximate negative entropy method are used to pick the first arrival point of this noisy seismic data, and the picking results are shown in Fig. 2(b), Fig. 2(c) and Fig. 2(d) .

[0079]Figure 2(b) is the picking result of the AIC method, and its...

experiment example 2

[0087] Experimental example 2 actual record

[0088] Figure 5 shows a set of actual three-component microseismic data, which contains 15 traces, each with 512 sampling points. AIC, STA / LTA and approximate negative entropy methods are used to extract the first arrival time respectively. It can be seen from the noisy data that the signal-to-noise ratio and signal amplitude on different components are inconsistent, and the data in the three component directions are picked up by AIC, STA / LTA and approximate negative entropy methods respectively. One of the data is extracted from the X, Y, and Z component picking results, and its single-channel waveform is shown in Figure 6. From the single-channel waveform diagram in Figure 6, it can also be seen that when the SNR is high, the positions of the first arrivals picked up by the three methods are close, and the picking error is small. When the SNR is low, the AIC and STA There is obviously a large error in the picking position of th...

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Abstract

The invention provides a microseism signal first arrival picking up method based on approximate negentropy, and belongs to the technical field of physical geography. The microseism signal first arrival picking up method based on approximate negentropy designs a suitable approximate negentropy function according to the characteristics of a microseism signal, and combines with a weighting function of the extremum difference of a negentropy-spectrum curve to set a threshold so as to realize accurate division of a signal area and a noise area and accurate pick-up of microseism signal first arrival. The microseism signal first arrival picking up method based on approximate negentropy has the advantages that according to the characteristics of the microseism signal, an approximate negentropy theory in the information theory is cited and a microseism signal first arrival picking up new method based on approximate negentropy is provided; compared with a current pick-up method, the new method can realize accurate pick-up of first arrival time in the lower signal to noise ratio condition and the signal to noise ratio can be as low as -12dB; and the calculating process is simple, and has high speed and high accuracy.

Description

technical field [0001] The invention belongs to the technical field of geophysics, in particular to a microseismic signal processing method. Background technique [0002] The exploration of unconventional oil and gas such as shale gas and coalbed methane is the focus of the future oil and gas industry and a subject of global concern. Hydraulic fracturing and microseismic detection technologies are increasingly used in oil and gas exploration. In microseismic signal identification or source location, because microseismic signals have the characteristics of large data volume, wide frequency distribution, and low signal-to-noise ratio, the detection and picking of the first arrival of microseismic events is an important and difficult problem. Find an accurate and fast microseismic first break picking method. [0003] In recent years, scholars at home and abroad have successively proposed a variety of time-domain or frequency-domain first-arrival picking algorithms based on si...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01V1/30
CPCG01V1/305
Inventor 田雅男李月倪卓吴宁于朋君李默
Owner JILIN UNIV
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