A time-frequency three-dimensional integrated electrical detection system and material method

Abstract

The present invention relates to the field of underground material detection and discloses a time-frequency three-dimensional integrated electrical detection system and a material method. The time-frequency three-dimensional integrated electrical detection system comprises: a transmitting device for transmitting a time-frequency electromagnetic signal in a target area; a receiving device for receiving the time-frequency electromagnetic signal transmitted by the transmitting device and propagated through the target area, and collecting data of measuring points on a survey line; a data processing module for processing the measuring point data collected by the receiving device, determining the full-field equivalent apparent resistivity of the measuring points on the survey line based on amplitude data and phase data, and further determining the geological structure characteristics of the target area based on the full-field equivalent apparent resistivity; a three-dimensional electrode arrangement module for arranging multiple electrodes around or inside the target area to form a three-dimensional electric field; and a synchronous observation control module for controlling the transmitting device, the receiving device and the three-dimensional electrode arrangement module to realize synchronous electrical observation of multiple wells and the ground.

Description

Technical Field

[0001] The present invention relates to the field of underground material detection, and in particular to a time-frequency three-dimensional integrated electrical detection system and a material method. Background Art

[0002] The basic principle of the time-frequency 3D integrated electrical method is to utilize the propagation characteristics of electromagnetic signals of different frequencies in the underground medium. By measuring and analyzing the response of these signals in the underground medium, the structure and properties of the underground medium can be inferred. This method combines time-frequency analysis technology with 3D electrical exploration methods to provide richer underground information.

[0003] Time-frequency analysis is a method that converts a one-dimensional time signal into a two-dimensional time-frequency function to describe the time-varying frequency characteristics of a signal or system. In the three-dimensional time-frequency integrated electrical method, time-frequency analysis is used to process and analyze received electromagnetic signals to extract information about the subsurface medium. Three-dimensional electrical prospecting is a method that infers the structure and properties of the subsurface medium by arranging multiple electrodes to form a three-dimensional electric field underground and measuring the electric field distribution. In the three-dimensional time-frequency integrated electrical method, three-dimensional electrical prospecting technology is used to obtain the three-dimensional resistivity distribution of the subsurface medium.

[0004] The existing time-frequency three-dimensional integrated electrical detection system still has some defects. For example, during the actual detection process, the influence of environmental noise will cause the electric field strength and magnetic field length to change, thereby affecting the accuracy of apparent resistivity and ultimately affecting the detection accuracy of the underlying medium. Summary of the Invention

[0005] The purpose of the present invention is to provide a time-frequency three-dimensional integrated electrical detection system and material method to solve the above technical problems.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A time-frequency three-dimensional integrated electrical detection system, comprising:

[0008] a transmitting device for transmitting a time-frequency electromagnetic signal in a target area, wherein the time-frequency electromagnetic signal has a predetermined frequency distribution range and component type;

[0009] A receiving device is arranged around or inside the target area, and is used to receive the time-frequency electromagnetic signal transmitted by the transmitting device and propagated through the target area, and collect the measurement point data on the survey line, wherein the measurement point data includes amplitude data and phase data;

[0010] A data processing module is used to process the measuring point data collected by the receiving device, determine the equivalent apparent resistivity of the entire field area of ​​the measuring points on the survey line based on the amplitude data and phase data, and further determine the geological structure characteristics of the target area based on the equivalent apparent resistivity of the entire field area;

[0011] A three-dimensional electrode arrangement module is used to arrange multiple electrodes around or inside the target area to form a three-dimensional electric field. The electrodes include a ground electrode group and an in-hole electrode group. The ground electrode group is arranged in a grid shape, and the in-hole electrode group arranges an electrode string in each borehole. The electrode string consists of several electrodes with fixed spacing;

[0012] The synchronous observation control module is used to control the transmitting device, receiving device and three-dimensional electrode arrangement module to achieve synchronous electrical observation of multiple holes and the ground.

[0013] As a further technical solution, the transmitting device includes a signal generator, a power amplifier and a transmitting antenna. The signal generator is used to generate an electrical signal with a predetermined frequency distribution range and component type; the power amplifier is used to amplify the electrical signal generated by the signal generator; and the transmitting antenna is used to convert the amplified electrical signal into a time-frequency electromagnetic signal and transmit it to the target area.

[0014] As a further technical solution, the receiving device includes an electric field sensor, a magnetic field sensor and a data acquisition card. The electric field sensor and the magnetic field sensor are used to receive time-frequency electromagnetic signals and convert the signals into electrical signals to obtain amplitude data and phase data. The potential sensor is used to measure the potential data of the measuring point. The data acquisition card is used to collect and digitize the above-mentioned electrical signals and potential data to obtain measuring point data.

[0015] As a further technical solution, the data processing module includes:

[0016] A data preprocessing unit, used for filtering and denoising the measurement point data collected by the receiving device;

[0017] The apparent resistivity calculation unit is used to calculate the pre-processed amplitude data and phase data using the formula:

[0018]

[0019] Calculate the equivalent apparent resistivity P of the entire field area of ​​the measuring point on the measuring line s ;

[0020] Wherein, α is the angular frequency, α=2πf, f is the frequency of the transmitted signal, μ is the magnetic permeability, K is the amplitude of the electric field strength, obtained from the amplitude data collected by the receiving device, Y is the amplitude of the magnetic field strength, obtained from the amplitude data collected by the receiving device, is the average phase obtained from multiple measurements;

[0021] The geological structure inversion unit is used to determine the geological structure characteristics of the target area using a three-dimensional inversion algorithm based on the equivalent apparent resistivity and measuring point potential data of the entire field area.

[0022] As a further technical solution, the process of obtaining the amplitude K of the electric field strength and the amplitude Y of the magnetic field strength is as follows:

[0023] Continuously measure and obtain the electric field strength E collected by the receiving device when the transmitting device is not working for n times A With the magnetic field strength H A

[0024] Continuously measure and obtain the additional electric field strength E caused by environmental factors collected by the receiving device when the transmitter is working for n times B With the additional magnetic field strength H B ;

[0025] By formula: The amplitude K of the electric field strength is calculated;

[0026] By formula: The amplitude K of the electric field strength is calculated;

[0027] Where i is the i-th measurement.

[0028] As a further technical solution, the data processing module further includes:

[0029] The potential calculation subunit is used to calculate the potential data and the electrode arrangement parameters after preprocessing, wherein the electrode arrangement parameters include: electrode position (x ρ ,y ρ ,z ρ ), the total number of electrodes M; by the formula:

[0030]

[0031] Calculate the potential V(x,y,z) at the current measuring point p(x,y,z);

[0032] Among them, U is the resistivity of the medium, I ρ is the current of the ρth electrode, g ρ The distance from the current measuring point p(x,y,z) to the ρth electrode (x ρ ,y ρ ,z ρ ) distance.

[0033] As a further technical solution, the calculated measuring point potential V(x, y, z) is compared with the actual measured measuring point potential V o Substitute (x, y, z) into the following equation;

[0034]

[0035] Calculate the error coefficient

[0036] Among them, δ1, δ2, and δ3 are weight coefficients, v is the calculated deviation value of the measuring point potential per unit time, and v0 is the actual measured deviation value of the measuring point potential per unit time;

[0037] The calculated error coefficient and error threshold Make comparisons;

[0038] like It is judged that there is an error in the measurement data and calibration is required.

[0039] As a further technical solution, the calculation formula for the deviation value v of the measuring point potential per unit time is:

[0040] The calculation formula of the deviation value v0 of the measuring point potential per unit time obtained by the actual measurement is:

[0041] Among them, V(x,y,z)(t) is the calculated curve of the measuring point potential changing with time, V o (x, y, z)(t) is the curve of the potential change of the measuring point with time obtained by actual measurement, t l ~t l+1 For unit time, V o (x,y,z) th (t), V(x,y,z) th (t) is the reference change curve.

[0042] A method for detecting materials using a time-frequency three-dimensional integrated electrical method is implemented based on the time-frequency three-dimensional integrated electrical method detection system.

[0043] Beneficial effects of the present invention:

[0044] The present invention takes into account the influence of environmental factors on the measurement results. By effectively processing the amplitudes of the electric and magnetic fields, it can maintain good accuracy and reliability under different environmental conditions. It is applicable both in areas with strong electromagnetic interference, such as cities, and in areas with complex natural environments, such as the wild, thus enhancing its practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will be further described below with reference to the accompanying drawings.

[0046] Figure 1 This is a system structure diagram of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] See also Figure 1 As shown, the present invention is a time-frequency three-dimensional integrated electrical detection system, comprising:

[0049] a transmitting device for transmitting a time-frequency electromagnetic signal in a target area, wherein the time-frequency electromagnetic signal has a predetermined frequency distribution range and component type;

[0050] A receiving device is arranged around or inside the target area, and is used to receive the time-frequency electromagnetic signal transmitted by the transmitting device and propagated through the target area, and collect the measurement point data on the survey line, wherein the measurement point data includes amplitude data and phase data;

[0051] A data processing module is used to process the measuring point data collected by the receiving device, determine the equivalent apparent resistivity of the entire field area of ​​the measuring points on the survey line based on the amplitude data and phase data, and further determine the geological structure characteristics of the target area based on the equivalent apparent resistivity of the entire field area;

[0052] A three-dimensional electrode arrangement module is used to arrange multiple electrodes around or within the target area to form a three-dimensional electric field. The electrodes include a ground electrode group and a borehole electrode group. The ground electrode group is arranged in a grid pattern. The borehole electrode group arranges an electrode string in each borehole. The electrode string consists of several electrodes with fixed spacing. For example, on the ground of the target area, the ground electrode group is arranged according to a grid spacing of 10 meters by 10 meters. At the same time, multiple suitable locations are selected in the target area for drilling. An electrode string is arranged in each borehole, and the electrode spacing on the electrode string is set to 5 meters.

[0053] Synchronous observation control module, used to control the transmitter, receiver and three-dimensional electrode arrangement module to achieve synchronous electrical observation of multiple wells and the ground. Clock synchronization technology can be used to ensure that the transmitter, receiver and three-dimensional electrode arrangement module can work in precise synchronization;

[0054] The transmitting device includes a signal generator, a power amplifier and a transmitting antenna. The signal generator is used to generate an electrical signal with a predetermined frequency distribution range and component type; the power amplifier is used to amplify the electrical signal generated by the signal generator; and the transmitting antenna is used to convert the amplified electrical signal into a time-frequency electromagnetic signal and transmit it to the target area.

[0055] The receiving device includes an electric field sensor, a magnetic field sensor and a data acquisition card. The electric field sensor and the magnetic field sensor are used to receive time-frequency electromagnetic signals and convert the signals into electrical signals to obtain amplitude data and phase data. The potential sensor is used to measure the potential data of the measuring point. The data acquisition card is used to collect and digitize the above-mentioned electrical signals and potential data to obtain measuring point data.

[0056] In this embodiment, time-frequency electromagnetic signals are used in conjunction with a three-dimensional electrode arrangement to construct a three-dimensional electric field, enabling comprehensive and multi-angle detection of underground geological conditions. A receiving device collects multiple types of measurement point data, including amplitude, phase, and potential. The data processing module deeply analyzes this data to accurately determine the equivalent apparent resistivity of the entire field, thereby clearly outlining the characteristics of the underground geological structure. This accurately presents information such as stratigraphic stratification, fault locations, and vein orientation, providing detailed and reliable geological information for mineral exploration. Furthermore, the changing characteristics of time-frequency electromagnetic signals as they propagate underground can accurately identify geological anomalies with electrical properties that differ from those of the surrounding medium, greatly increasing the probability of discovering potential mineral resources and reducing the risk of missed exploration.

[0057] The data processing module includes:

[0058] A data preprocessing unit, used for filtering and denoising the measurement point data collected by the receiving device;

[0059] The apparent resistivity calculation unit is used to calculate the pre-processed amplitude data and phase data using the formula:

[0060]

[0061] Calculate the equivalent apparent resistivity P of the entire field area of ​​the measuring point on the measuring line s ;

[0062] Wherein, α is the angular frequency, α=2πf, f is the frequency of the transmitted signal, μ is the magnetic permeability, K is the amplitude of the electric field strength, obtained from the amplitude data collected by the receiving device, Y is the amplitude of the magnetic field strength, obtained from the amplitude data collected by the receiving device, is the average phase obtained from multiple measurements;

[0063] The geological structure inversion unit is used to determine the geological structure characteristics of the target area using a three-dimensional inversion algorithm based on the equivalent apparent resistivity and point potential data of the entire field. The three-dimensional inversion algorithm uses one of the least squares inversion method, conjugate gradient method, simulated annealing algorithm, and genetic algorithm. These algorithms are all existing technologies and can be directly obtained by those skilled in the art, so they will not be described in detail here.

[0064] The process of obtaining the amplitude K of the electric field strength and the amplitude Y of the magnetic field strength is as follows:

[0065] Continuously measure and obtain the electric field strength E collected by the receiving device when the transmitting device is not working for n times A With the magnetic field strength H A

[0066] Continuously measure and obtain the additional electric field strength E caused by environmental factors collected by the receiving device when the transmitter is working for n times B With the additional magnetic field strength H B ;

[0067] By formula: The amplitude K of the electric field strength is calculated;

[0068] By formula: The amplitude K of the electric field strength is calculated;

[0069] Where i is the i-th measurement.

[0070] In this embodiment, a method for obtaining the equivalent apparent resistivity of the entire field area of ​​the measuring point on the measuring line is provided. Specifically, the formula and The amplitude K of the electric field intensity and the amplitude K of the electric field intensity are calculated respectively; through the above formula, the actual electric field intensity E A , magnetic field strength H A The additional electric field strength E caused by environmental factors B , additional magnetic field strength H B Calculate the standard deviation. The standard deviation reflects the degree of data dispersion. When environmental noise exists, the dispersion of the measured data will increase. Using the standard deviation for processing can reduce the impact of noise on the amplitude calculation, making the obtained electric field strength amplitude and magnetic field strength amplitude closer to the true value. By calculating the standard deviation, the measurement error caused by accidental factors such as instantaneous electromagnetic interference can be reduced, making the calculation results of the electric field strength amplitude and magnetic field strength amplitude more stable and reliable. In actual detection, the environmental conditions are complex and changeable. The above technical solution can enhance the anti-interference ability of the data and ensure the accuracy of the subsequent apparent resistivity calculation.

[0071] Then substitute the calculated amplitude K of the electric field strength and the amplitude K of the electric field strength into the formula: The equivalent apparent resistivity P of the entire field area of ​​the measuring point on the measuring line is calculated. s , the electric field strength and magnetic field strength amplitude processed by standard deviation are used to calculate the equivalent apparent resistivity of the entire field area, which can more accurately reflect the electrical characteristics of the underground medium. Since some environmental noise interference is eliminated, the calculated apparent resistivity result is closer to the true resistivity of the underground medium, which helps to more accurately identify the distribution of underground geological structures and geological bodies, such as faults and ore bodies.

[0072] It should be noted that the impact of environmental factors on the measurement results is taken into consideration. Through effective processing of the electric and magnetic field amplitudes, it can maintain good accuracy and reliability under different environmental conditions. It is applicable both in areas with strong electromagnetic interference such as cities and in areas with complex natural environments such as the wild, thereby enhancing its practical application value.

[0073] The data processing module also includes:

[0074] The potential calculation subunit is used to calculate the potential data and the electrode arrangement parameters after preprocessing, wherein the electrode arrangement parameters include: electrode position (x ρ ,y ρ ,z ρ ), the total number of electrodes M; by the formula:

[0075]

[0076] Calculate the potential V(x,y,z) at the current measuring point p(x,y,z);

[0077] Among them, U is the resistivity of the medium, I ρ is the current of the ρth electrode, g ρ The distance from the current measuring point p(x,y,z) to the ρth electrode (x ρ ,y ρ ,z ρ ) distance.

[0078] Compare the calculated measuring point potential V(x,y,z) with the actual measured measuring point potential V o Substitute (x, y, z) into the following equation;

[0079]

[0080] Calculate the error coefficient

[0081] Among them, δ1, δ2, and δ3 are weight coefficients, v is the calculated deviation value of the measuring point potential per unit time, and v0 is the actual measured deviation value of the measuring point potential per unit time;

[0082] The calculated error coefficient and error threshold Make comparisons;

[0083] like It is judged that there is an error in the measurement data and calibration is required. The calibration method includes checking the contact resistance between the electrode and the ground. If the contact resistance is too large, the contact between the electrode and the ground is reprocessed.

[0084] The calculation formula for the deviation value v of the measuring point potential per unit time is:

[0085] The calculation formula of the deviation value v0 of the measuring point potential per unit time obtained by the actual measurement is:

[0086] Among them, V(x,y,z)(t) is the calculated curve of the measuring point potential changing with time, V o (x, y, z)(t) is the curve of the potential change of the measuring point with time obtained by actual measurement, t l ~t l+1 For unit time, V o (x,y,z) th (t), V(x,y,z) th (t) is the reference change curve.

[0087] In this embodiment, by Calculate the error coefficient By using relative error to quantitatively compare the calculated potential with the measured potential, the accuracy of the measurement data can be accurately determined. Through quantitative evaluation, minute data deviations can be promptly identified, ensuring that subsequent geological analysis based on potential data is based on reliable data, laying the foundation for high-precision geological exploration. Once the measurement data error exceeds the threshold, the measurement system is calibrated and the contact resistance between the electrode and the ground is checked. This can resolve signal transmission anomalies caused by poor contact, keep the measurement system in optimal working condition, and ensure the stability and reliability of data acquisition.

[0088] At the same time, through the formula: and

[0089] The exponential accumulation of the calculated potential and the measured potential per unit time can more clearly present the error development trend of the measurement system over a longer time span, and judge whether it is gradually stabilizing or there is an increasing error drift, which is of great significance for evaluating the long-term reliability and stability of the system. Based on the error trend presented by the exponential accumulation, a certain degree of prediction of the future error situation can be made. If it is found that the error shows an exponential growth trend, measures can be taken in advance, such as strengthening equipment maintenance, optimizing measurement methods, etc., to avoid further expansion of the error and causing the measurement results to lose their meaning, and comprehensively achieve the improvement of the error coefficient. For the purpose of accuracy.

[0090] A method for detecting materials using a time-frequency three-dimensional integrated electrical method is implemented based on the time-frequency three-dimensional integrated electrical method detection system.

[0091] It should be noted that the calculation formulas and various parameters involved in the calculations in the present invention have been dimensionally processed in advance, and the process of dimensionless processing is well known in the industry and will not be described here.

[0092] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A time-frequency three-dimensional integrated electrical detection system, characterized in that: include: a transmitting device for transmitting a time-frequency electromagnetic signal in a target area, wherein the time-frequency electromagnetic signal has a predetermined frequency distribution range and component type; A receiving device is arranged around or inside the target area, and is used to receive the time-frequency electromagnetic signal transmitted by the transmitting device and propagated through the target area, and collect the measurement point data on the survey line, wherein the measurement point data includes amplitude data and phase data; A data processing module is used to process the measuring point data collected by the receiving device, determine the equivalent apparent resistivity of the entire field area of ​​the measuring points on the survey line based on the amplitude data and phase data, and further determine the geological structure characteristics of the target area based on the equivalent apparent resistivity of the entire field area; The data processing module includes: A data preprocessing unit, used for filtering and denoising the measurement point data collected by the receiving device; The apparent resistivity calculation unit is used to calculate the pre-processed amplitude data and phase data using the formula: Calculate the equivalent apparent resistivity of the entire field area of ​​the measuring point on the survey line ; in, is the angular frequency, , is the frequency of the transmitted signal, is the magnetic permeability, is the amplitude of the electric field strength, obtained from the amplitude data collected by the receiving device, is the amplitude of the magnetic field strength, obtained from the amplitude data collected by the receiving device, is the average phase obtained from multiple measurements; The geological structure inversion unit is used to determine the geological structure characteristics of the target area using a three-dimensional inversion algorithm based on the equivalent apparent resistivity and measuring point potential data of the entire field area; The amplitude of the electric field strength , the amplitude of the magnetic field strength The acquisition process is: Continuously measure and obtain the electric field strength collected by the receiving device when the transmitter is not working for n times and magnetic field strength ; Continuously measure and obtain the additional electric field strength caused by environmental factors collected by the receiving device when the transmitter is working n times With additional magnetic field strength ; By formula: Calculate the amplitude of the electric field strength ; By formula: Calculate the amplitude of the magnetic field strength ; in, For the Secondary measurement; A three-dimensional electrode arrangement module is used to arrange multiple electrodes around or inside the target area to form a three-dimensional electric field. The electrodes include a ground electrode group and an in-hole electrode group. The ground electrode group is arranged in a grid shape, and the in-hole electrode group arranges an electrode string in each borehole. The electrode string consists of several electrodes with fixed spacing; The synchronous observation control module is used to control the transmitting device, receiving device and three-dimensional electrode arrangement module to achieve synchronous electrical observation of multiple holes and the ground.

2. The time-frequency three-dimensional integrated electrical detection system according to claim 1 is characterized in that: The transmitting device includes a signal generator, a power amplifier and a transmitting antenna, wherein the signal generator is used to generate an electrical signal with a predetermined frequency distribution range and component type; the power amplifier is used to amplify the electrical signal generated by the signal generator; The transmitting antenna is used to convert the amplified electrical signal into a time-frequency electromagnetic signal and transmit it to a target area.

3. The time-frequency three-dimensional integrated electrical detection system according to claim 1 is characterized in that: The receiving device includes an electric field sensor, a potential sensor, a magnetic field sensor and a data acquisition card. The electric field sensor and the magnetic field sensor are used to receive time-frequency electromagnetic signals and convert the time-frequency electromagnetic signals into electrical signals to obtain amplitude data and phase data. The potential sensor is used to measure the potential data of the measuring point. The data acquisition card is used to collect and digitize the above-mentioned electrical signals and potential data to obtain measuring point data.

4. The time-frequency three-dimensional integrated electrical detection system according to claim 3 is characterized in that: The data processing module also includes: The potential calculation subunit is used to calculate the measuring point potential based on the pre-processed potential data and electrode layout parameters. The electrode layout parameters include: electrode position , the total number of electrodes M; through the formula: ； ； Calculate the current measuring point The potential at ; in, is the resistivity of the medium, For the The current of each electrode, Current measuring point To electrodes distance.

5. The time-frequency three-dimensional integrated electrical detection system according to claim 4 is characterized in that: The calculated measuring point potential The actual measured potential of the measuring point Substitute into the following formula; Calculate the error coefficient ; in, 、 、 is the weight coefficient, is the calculated deviation value of the measuring point potential per unit time, It is the deviation value of the potential of the measuring point obtained by actual measurement per unit time; The calculated error coefficient and error threshold Make comparisons; like , it is judged that there is an error in the measurement data and calibration is required.

6. The time-frequency three-dimensional integrated electrical detection system according to claim 5 is characterized in that: The calculated deviation value of the measuring point potential per unit time The calculation formula is: ； The deviation value of the potential of the measuring point obtained by the actual measurement per unit time The calculation formula is: ； in, is the calculated curve of the measuring point potential changing with time, is the curve of the potential change of the measuring point over time obtained by actual measurement, is the unit time, 、 is the reference change curve.

7. A method for detecting substances using a three-dimensional time-frequency integrated electrical method, characterized in that: The method is implemented based on the time-frequency three-dimensional integrated electrical detection system described in any one of claims 1-6.

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