Electromagnetic emission control system and method for full-depth stratum scanning

Abstract

The invention discloses an electromagnetic emission control system for full-depth stratum scanning. The electromagnetic emission control system comprises an electromagnetic emission device, an electromagnetic receiving device and a closed-loop control device, the electromagnetic emission device is connected with the closed-loop control device and is used for adjusting current input according to a control signal of the closed-loop control device and carrying out stepped and pulse type electromagnetic emission; the electromagnetic receiving device is connected with the closed-loop control device and is used for capturing, processing and feeding back induction signals; the closed-loop control device analyzes the induction signal in real time and generates a control signal capable of dynamically adjusting emission current and frequency. According to the sensing signal, the detection blind area is obviously reduced by changing the emission frequency of the electromagnetic signal when the blind area exists.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic emission, and particularly to an electromagnetic emission control system and method for full-depth formation scanning. Background Art

[0002] When placing transmitting and receiving coils on the ground, an electromagnetic field is generated by the current in the transmitting coil. This electromagnetic field enters the ground and will be reflected and scattered when encountering formations and resources with different conductivities. The greater the current, the stronger the intensity of the generated electromagnetic field, and the corresponding increase in the detection depth and range. The magnitude of the current directly determines the depth that the electromagnetic wave can penetrate and the influence range. Different frequencies correspond to different detection depths. High-frequency currents are more suitable for detecting shallow details, while low-frequency currents are more suitable for detecting deep structures.

[0003] Existing electromagnetic detection systems usually adopt fixed current waveforms, which can detect underground structures at a certain depth, but there are obvious deficiencies in the detection range and avoiding detection blind spots. Due to the failure to fully consider the diversity and complexity of underground media in terms of current intensity and waveform, it often leads to insufficient coverage of shallow information and severe attenuation of deep signals, affecting the overall detection effect. Especially in the detection of very shallow layers, the turn-off delay time affects the transient response of shallow exploration, easily resulting in detection blind spots and missing important geological information. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides an electromagnetic emission control system and method for full-depth formation scanning to solve the technical problems of detection blind spots, low detection resolution, and low accuracy existing in the prior art.

[0005] The present invention provides an electromagnetic emission control system for full-depth formation scanning, including: an electromagnetic emission device, an electromagnetic reception device, and a closed-loop control device;

[0006] The electromagnetic emission device is connected to the closed-loop control device and is used to adjust the current input according to the control signal of the closed-loop control device to perform stepped and pulsed electromagnetic emissions; the electromagnetic reception device is connected to the closed-loop control device and is used to capture, process, and feedback induction signals; the closed-loop control device analyzes the induction signals in real time and generates control signals for dynamically adjusting the emission current and frequency.

[0007] Further, the electromagnetic emission device includes: a power supply, a transmitting coil, and a driving module; the power supply is connected to the driving module and is used to supply power to the driving module; the driving module is respectively connected to the closed-loop control device and the transmitting coil, and the driving module adjusts the input current and emission frequency of the transmitting coil according to the control signal of the closed-loop control device; the transmitting coil generates electromagnetic signals according to the emission frequency and input current.

[0008] Further, the electromagnetic receiving device includes: a receiving coil, an amplifier, and a data acquisition module; the receiving coil is connected to the amplifier and is used for receiving induction signals; the amplifier is connected to the data acquisition module and is used for amplifying the received induction signals; the data acquisition module is connected to the closed-loop control device and is used for acquiring and transmitting the received induction signals.

[0009] The present invention also provides an electromagnetic emission control method for full-depth formation scanning, including the following steps;

[0010] Step 1: Set the initial current value, initial frequency, current value increment, frequency increment, current value increment coefficient, frequency increment coefficient, and the number of pulses at each level;

[0011] Step 2: Calculate the current current value and the current frequency according to the current value increment, frequency increment, current value increment coefficient, and frequency increment coefficient;

[0012] Step 3: Transmit electromagnetic pulses according to the calculated current current value, current frequency, and the number of pulses;

[0013] Step 4: Acquire the induction signal and optimize the induction signal;

[0014] When there is a blind area in the detection area feedback by the induction signal, keep the current current value increment coefficient unchanged, adjust the frequency increment coefficient, and return to Step 2;

[0015] When there is no blind area in the detection area feedback by the induction signal or the range of the existing blind area meets the exploration requirements, keep the current frequency increment coefficient unchanged, increment the current value increment coefficient, and return to Step 2;

[0016] When the current current value reaches the maximum current value, end the formation scanning process.

[0017] Further, in the above Step 2, the formulas for calculating the current current value and the current frequency are respectively:

[0018] i = i 0 + k 1 Δi;

[0019] f = f 0 + k 2 Δf;

[0020] In the formula, i is the current current value; i 0 is the initial current value; k 1 is the current value increment coefficient; Δi is the current value increment; f is the current frequency; f 0 is the initial frequency; k 2 is the frequency increment coefficient; Δf is the frequency increment.

[0021] Further, in the step 4, the method for optimizing the induction signal is as follows:

[0022] The induction signal is optimized by reducing the influence of current on the induction signal. The specific formula is as follows:

[0023] f(t) = f a+1 (t) - (f a (t) · i a+1 ^2 / i a ^2)

[0024] Take f a (t) as the underground induction signal during the time period from tt 2+a to tt 2+a+1 .

[0025] Advantages of the present invention:

[0026] According to the induction signal, when there is a blind area, the present invention significantly reduces the detection blind area by changing the transmission frequency of the electromagnetic signal. The present invention adopts a stepped segmented excitation with the current increasing from small to large, and each level of current corresponds to a specific detection depth, improving the coverage integrity of the shallow layer and the deep layer. At the same time, the present invention combines the skin depth formula to achieve independent excitation and signal separation of different depth strata, avoiding the superposition of shallow and deep layer signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings. The drawings are schematic and should not be construed as imposing any limitation on the present invention. In the drawings:

[0028] Figure 1 is the system block diagram of a specific embodiment of the present invention;

[0029] Figure 2 is the flowchart of a specific embodiment of the present invention;

[0030] Figure 3 is the schematic diagram of the stepped change of current in a specific embodiment of the present invention;

[0031] Figure 4 is the schematic diagram of the frequency change in a specific embodiment of the present invention;

[0032] Figure 5 is the schematic diagram of quantitative transmission and reception in a specific embodiment of the present invention;

[0033] Figure 6 is the schematic diagram of the detection process in a specific embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0035] The present invention will be further clarified below with reference to specific embodiments. Those skilled in the art should understand that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Modifications of various equivalent forms of the present invention fall within the scope defined by the appended claims of this application.

[0036] As Figure 1 shown, the present invention provides an electromagnetic emission control system for full-depth formation scanning, including: an electromagnetic emission device, an electromagnetic reception device, and a closed-loop control device;

[0037] The electromagnetic emission device is connected to the closed-loop control device and is used to adjust the current input according to the control signal of the closed-loop control device to perform stepped and pulsed electromagnetic emissions; the electromagnetic reception device is connected to the closed-loop control device and is used to capture, process, and feedback induction signals; the closed-loop control device analyzes the induction signals in real time and generates control signals for dynamically adjusting the emission current and frequency.

[0038] The electromagnetic emission device includes: a power supply, an emission coil, and a drive module; the power supply is connected to the drive module and is used to supply power to the drive module; the drive module is respectively connected to the closed-loop control device and the emission coil, and the drive module adjusts the input current and emission frequency of the emission coil according to the control signal of the closed-loop control device; the emission coil generates electromagnetic signals according to the emission frequency and input current.

[0039] The electromagnetic reception device includes: a reception coil, an amplifier, and a data acquisition module; the reception coil is connected to the amplifier and is used to receive induction signals; the amplifier is connected to the data acquisition module and is used to amplify the received induction signals; the data acquisition module is connected to the closed-loop control device and is used to collect and transmit the received induction signals.

[0040] As Figure 2 shown, the present invention also provides an electromagnetic emission control method for full-depth formation scanning, including the following steps;

[0041] Step 1: Set the initial current value, initial frequency, current value increment, frequency increment, current value increment coefficient, frequency increment coefficient, and the number of pulses at each level;

[0042] Step 2: Calculate the current current value and the current frequency according to the current value increment, the frequency increment, the current value increment coefficient, and the frequency increment coefficient;

[0043] The formulas are respectively:

[0044] i = i 0 + k 1 Δi;

[0045] f = f 0 + k 2 Δf;

[0046] In the formula, i is the current current value; i 0 is the initial current value; k 1 is the current value increment coefficient; Δi is the current value increment; f is the current frequency; f 0 is the initial frequency; k 2 is the frequency increment coefficient; Δf is the frequency increment;

[0047] Step 3: Transmit electromagnetic pulses according to the calculated current current value, the current frequency, and the number of pulses;

[0048] During the process of transmitting electromagnetic pulses, the actual current can also be adjusted through PI control to make it reach the calculated current current value;

[0049] Step 4: Obtain the induction signal and optimize the induction signal by reducing the influence of the current on the induction signal. The specific formula is as follows:

[0050] f(t) = f a+1 (t) - (f a (t) · i a+1 ^2 / i a ^2)

[0051] Take f a (t) as the underground induction signal in the time period from tt 2+a to tt 2+a+1 ;

[0052] As Figure 5 shown, set the underground induction signal excited by the a-th transmitted current as f a (t), set the start time of the transmitted current as t 1 , the start time of turn-off as t 2 , the complete turn-off time of the a-th transmitted current as t 2+a , and the last time point of the corresponding received signal as tt 2+a , then, take f 1 (t) as the underground induction signal in the time period from t 2 to tt 3 , f a+1(t)-(f a (t)·i a+1 ^2 / i a ^2) as tt 2+a To tt 2+a+1 The underground induction signal of the period, and so on to tt 2+n-1 To tt 2+n time.

[0053] The received induction signal is converted into information such as the resistivity and dielectric constant of the underground medium. By analyzing the response curves at different current stages, a three-dimensional model of the underground structure can be gradually constructed to identify the distribution of resources at different depths. The duration of current action is affected by many factors, especially in deep electromagnetic detection. Multiple parameters ensure that the electromagnetic wave can fully penetrate the formation and return the signal, among which the skin depth is the most important.

[0054] Skin depth refers to the effective thickness of the transmission path in the skin effect, which determines the penetration depth of electromagnetic waves in underground media. The calculation formula of skin depth δ is:

[0055]

[0056] Where μ is the magnetic permeability, σ is the electrical conductivity, and f is the frequency.

[0057] Lower frequencies produce a greater skin depth, allowing electromagnetic waves to penetrate deeper, but require a longer time to interact with deeper formations to ensure that the electromagnetic field fully affects the target depth. Higher frequencies mainly act on shallower areas and have a relatively short action time because electromagnetic waves decay rapidly at high frequencies due to the skin effect.

[0058] Highly conductive materials will cause electromagnetic waves to decay faster, so shallow detection takes less time, while deep detection may require longer action time due to the attenuation of high-frequency signals. Highly resistive materials allow electromagnetic waves to penetrate deeper, so the current action time needs to be extended accordingly. Higher magnetic permeability will reduce the skin depth, causing electromagnetic waves to decay rapidly in ferromagnetic materials, and the current action time needs to be adjusted to ensure that deep signals can be detected.

[0059] The current current value is used to adjust the transmission power of the current electromagnetic signal, which is equivalent to adjusting the detection depth of the electromagnetic signal; the current frequency is used to adjust the skin depth, which is equivalent to adjusting the detection time of a certain detection depth;

[0060] When there are many blind spots in the detection area of ​​the induction signal feedback, keep the current current value increment coefficient unchanged, reduce the blind spots by adjusting the frequency increment coefficient, return to step 2, and change the current frequency. Because the number of pulses is fixed, adjusting the frequency is equivalent to adjusting the detection time of the current depth to detect the blind spots; the change of frequency is as follows: Figure 4as shown;

[0061] When there is no blind area in the detection area feedback by the induction signal or there are fewer blind areas that meet the exploration requirements, keep the current frequency increment coefficient unchanged, increment the current value increment coefficient, and return to step 2 to increase the current value and the detection depth; as Figure 3 shown, at this time the current value increases in a stepwise manner; the fewer blind areas that meet the exploration requirements can be set according to the actual exploration requirements;

[0062] When the current value reaches the maximum current value, end the formation scanning process.

[0063] Figure 6 From left to right in [description of the figure], although the detection depth in the first figure is deeper, only a part of the underground resources can be detected. This indicates that there is a large blind area in the current detection range and the target resources are not fully covered. The detection depth in the second figure decreases and the covered area is more concentrated. Although more resources are detected, there are still undetected areas. After continuing to adjust the current intensity or frequency in the third figure, since the detection depth is still limited, some underground resources are still not fully detected. Figure 6 In the first three figures in [description of the figure], the detection depths are different, and the detected underground resources are also different, and there are detection blind areas to varying degrees. The current intensity and frequency in the fourth figure are more optimally adjusted, and finally an ideal detection effect is achieved. At this time, the detection range covers most of the target area, the blind area is minimized, and the detection depth and the covered area reach a balance.

[0064] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. An electromagnetic emission control system for full-depth stratum scanning, characterized in that: include: Electromagnetic transmitting device, electromagnetic receiving device and closed-loop control device; The electromagnetic transmitting device is connected to the closed-loop control device, and is used to adjust the current input according to the control signal of the closed-loop control device to perform step-type and pulse-type electromagnetic transmission; the electromagnetic receiving device is connected to the closed-loop control device, and is used to capture, process and feedback the induction signal; the closed-loop control device analyzes the induction signal in real time and generates a control signal that can dynamically adjust the transmission current and frequency.

2. The electromagnetic emission control system for full-depth stratum scanning according to claim 1, characterized in that: The electromagnetic transmitting device includes: a power supply, a transmitting coil and a driving module; the power supply is connected to the driving module for supplying power to the driving module; the driving module is respectively connected to the closed-loop control device and the transmitting coil, and the driving module adjusts the input current and the transmitting frequency of the transmitting coil according to the control signal of the closed-loop control device; the transmitting coil generates an electromagnetic signal according to the transmitting frequency and the input current.

3. The electromagnetic emission control system for full-depth stratum scanning according to claim 2, characterized in that: The electromagnetic receiving device includes: a receiving coil, an amplifier and a data acquisition module; the receiving coil is connected to the amplifier for receiving an induction signal; the amplifier is connected to the data acquisition module for amplifying the received induction signal; the data acquisition module is connected to the closed-loop control device for collecting and transmitting the received induction signal.

4. A method for controlling electromagnetic emission for full-depth stratum scanning, applicable to the electromagnetic emission control system for full-depth stratum scanning as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Set the initial current value, initial frequency, current value increment, frequency increment, current value increment coefficient, frequency increment coefficient and the number of pulses at each level; Step 2: Calculate the current value and the current frequency according to the current value increment, the frequency increment, the current value increment coefficient and the frequency increment coefficient; Step 3: Emitting electromagnetic pulses according to the calculated current current value, current frequency and number of pulses; Step 4: Obtain the sensing signal and optimize the sensing signal; When there is a blind spot in the detection area of ​​the induction signal feedback, keep the current current value increment coefficient unchanged, adjust the frequency increment coefficient, and return to step 2; When there is no blind spot in the detection area fed back by the induction signal or the existing blind spot range meets the exploration requirements, keep the current frequency increment coefficient unchanged, increase the current value increment coefficient, and return to step 2; When the current value reaches the maximum current value, the formation scanning process ends.

5. The electromagnetic emission control method for full-depth stratum scanning according to claim 4, characterized in that: In step 2, the formulas for calculating the current current value and the current frequency are: i=i0+k1Δi; f=f0+k2Δf; In the formula, i is the current current value; i0 is the initial current value; k1 is the current value increment coefficient; Δi is the current value increment; f is the current frequency; f0 is the initial frequency; k2 is the frequency increment coefficient; Δf is the frequency increment.

6. The electromagnetic emission control method for full-depth stratum scanning according to claim 4 or 5, characterized in that: In step 4, the method for optimizing the sensing signal is: The induction signal is optimized by reducing the influence of current on the induction signal. The specific formula is as follows: f(t)=f a+1 (t)-(f a (t)·i a+1 ^2 / i a ^2) f a (t) as tt 2+a To tt 2+a+1 Underground induction signals during the period.

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