A method and system for extracting weak signals

Abstract

The present invention relates to the field of gravity, magnetic and electric data processing for oil and gas exploration, and particularly relates to a method and a system for extracting weak signals. The method of the present invention includes the following steps: collecting data, calculating the square of the amplitude of all sampling points of each trace of data; performing filtering processing; and obtaining an acoustic far-detection result profile. The method of the present invention uses the detected data as a reference signal, and adopts a correlation detection method to extract weak signals. The processed data has a high signal-to-noise ratio in imaging and can obtain an ideal processing effect.

Description

Technical Field

[0001] The present invention relates to the field of heavy magnetic and electric data processing in oil and gas exploration, and particularly relates to a method and system for extracting weak signals. Background Art

[0002] The principle of related detection methods is to multiply a reference signal by the detected data and then perform low-pass filtering to obtain data with high signal-to-noise ratio. The frequency of the reference signal is the same as that of the detected signal. If the detected signal is known, the known detected signal can be used as the reference signal. In the heavy magnetic and electric methods of oil and gas exploration, the detected signal is unknown, and usually an approximate detected signal is used as the reference signal. Since the approximate detected signal is different from the detected signal, the detection effect is generally not ideal. Therefore, how to select a suitable reference signal and use the related detection method to detect weak signals is an inevitable requirement for extracting weak signals.

[0003] Chinese invention patent CN108957120B discloses a method and system for extracting weak signals. The method includes: collecting weak signals input externally at a set frequency to obtain a sampling sequence, where the sampling sequence includes multiple signal points and multiple frequency components; performing a fast Fourier transform on the sampling sequence to obtain a transformed sequence; calculating the frequencies corresponding to the signal points with the highest absolute value of the amplitude in each segment of the transformed sequence; generating a standard sine-cosine sequence according to the transformed sequence; calculating the correlation value between the standard sine-cosine sequence and the sampling sequence; calculating the phase value and amplitude value of each frequency component according to the correlation value; obtaining the maximum amplitude value of the amplitude values of each frequency component through a successive comparison method; updating the amplitude values of all frequency components through an amplitude threshold and the maximum amplitude value; and extracting the weak signal according to the frequency corresponding to the signal point with the highest absolute value of the amplitude, the phase value of each frequency component, and the updated amplitude value of the frequency component. This method has relatively complex steps.

[0004] Accurate processing of heavy magnetic and electric data is of great significance for oil and gas exploration. Currently, a simple and effective method for extracting weak signals is needed. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and system for extracting weak signals. The method of the present invention uses the detected data as the reference signal and adopts the related detection method to extract weak signals, and can obtain an ideal processing effect.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for extracting weak signals, which includes the following steps:

[0008] Collect data and calculate the square of the amplitude of all sampling points of each trace of data;

[0009] Perform filtering processing;

[0010] Obtain the acoustic wave long - range detection result profile.

[0011] Furthermore, the collected data is the gravity - magnetic - electric signal with certain morphological regular characteristics.

[0012] Furthermore, select a zero - phase low - frequency filter for filtering processing.

[0013] The present invention provides a system for extracting weak signals, which includes an input module, a data processing module, a filtering processing module, and an output module connected in sequence;

[0014] The data input by the input module is the gravity - magnetic - electric signal with certain morphological regular characteristics;

[0015] The data processing module is used to calculate the square of the amplitude of all sampling points of each channel of data.

[0016] Furthermore, the filtering processing module is a zero - phase low - frequency filter, and outputs low - frequency data.

[0017] Furthermore, the output module outputs the acoustic wave long - range detection result profile.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The method of the present invention uses the detected data as a reference signal, adopts the correlation detection method to extract weak signals, and has a high signal - to - noise ratio in data processing imaging, and can obtain an ideal processing effect.

[0020] The method and system for extracting weak signals of the present invention are simple to operate and suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0022] Figure 1 It is a flow chart of the method for extracting weak signals described in Embodiment 1 of the present invention;

[0023] Figure 2 It is the original signal diagram;

[0024] Figure 3 It is a schematic diagram of denoising using a known signal as a reference signal;

[0025] Figure 4 It is a schematic diagram of the data extracted by the method described in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0027] It should be noted that the terms used herein are merely for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, and / or combinations thereof.

[0028] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0029] Embodiment 1

[0030] As Figure 1 shown, the method for extracting weak signals includes the following steps:

[0031] Step 101, input data;

[0032] The input data is a gravity, magnetic, and electric signal with certain morphological regular features.

[0033] Step 102, select one channel of data.

[0034] Step 103, select the first sampling point of this channel of data.

[0035] Step 104, calculate the square of the amplitude of this sampling point:

[0036] The formula for calculating the square of the amplitude of this sampling point is as follows:

[0037] A 1 = A · A

[0038] A 1 is the output amplitude value, and A is the input amplitude value.

[0039] Step 105, calculate the squares of the amplitudes of all sampling points of this channel of data;

[0040] The formula is as follows:

[0041] A 1i = A i · A i

[0042] i = 1, 2, 3..., N

[0043] A 1i is the i-th output amplitude value, and A i is the i-th input amplitude value, and N is the number of sampling points.

[0044] Step 106: Process all data according to Steps 2 - 5;

[0045] Step 107: Filtering process: Select a zero-phase low-frequency filter and output low-frequency data.

[0046] Step 108: Output the acoustic wave long-distance detection result profile.

[0047] The schematic diagram of using this embodiment to implement weak signal extraction and process data is as Figure 4 shown. The original signal diagram, that is, the schematic diagram of not processing data using the method described in the embodiment is as Figure 2 shown, and the schematic diagram of using a known signal as a reference signal for denoising is as Figure 3 shown. It can be seen from the figure that the denoising effect of the correlation detection method using a known signal as a reference signal is the same as the imaging effect of processing data using the method of this embodiment, and ideal data processing results can be obtained by processing data using the method of this embodiment.

[0048] Embodiment 2

[0049] A system for extracting weak signals includes an input module, a data processing module, a filtering processing module, and an output module connected in sequence;

[0050] The data input by the input module is the gravity, magnetic, and electric signals with certain morphological regularity characteristics;

[0051] The data processing module is used to calculate the square of the amplitude of all sampling points of each channel of data.

[0052] The filtering processing module is a zero-phase low-frequency filter and outputs low-frequency data.

[0053] The output module outputs the acoustic wave long-distance detection result profile.

[0054] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for extracting weak signals, characterized in that, it includes the following steps: Step 101, input data; The input data is a gravity, magnetic and electric signal with certain morphological regular characteristics; Step 102, select one channel of data; Step 103, select the first sampling point of this channel of data; Step 104, calculate the square of the amplitude of this sampling point: Calculate the square of the amplitude of this sampling point, and the formula is as follows: A 1 = A·A A 1 is the output amplitude value, and A is the input amplitude value; Step 105, calculate the squares of the amplitudes of all sampling points of this channel of data; The formula is as follows: A 1i = A i · A i i = 1, 2, 3..., N A 1i is the i-th output amplitude value, A i is the i-th input amplitude value, and N is the number of sampling points; Step 106, process all data according to Steps 102 to 105; Step 107, filtering processing: select a zero-phase low-frequency filter and output low-frequency data; Step 108, output the acoustic far-detection result profile.

Images