Electromagnetic field-based layered medium detection method, storage medium, and electronic device

Abstract

The application provides a layered medium detection method based on an electromagnetic field, a storage medium and an electronic device, including: obtaining electric field data and magnetic field data of a target to be detected; determining impedance of the target to be detected, and determining an apparent resistivity curve of the target to be detected; determining a resistivity value of a current first layer medium of the target to be detected based on the apparent resistivity; determining a thickness of the current first layer medium of the target to be detected based on the apparent resistivity curve of the target to be detected and the resistivity value of the current first layer medium; and performing layer-by-layer impedance stripping on the target to be detected based on the resistivity value and the thickness of the current first layer medium, to determine a resistivity value and a thickness of each layer medium of the target to be detected. The method effectively calculates the thickness and resistivity of each layer medium by layer-by-layer stripping of each layer medium of the target to be detected, realizes layered medium detection of the target to be detected, and has the advantages of non-contact, no pollution, low cost, simple operation, high speed and no need of coupling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of layered medium detection, in particular to a layered medium detection method based on electromagnetic field, a storage medium and an electronic device. BACKGROUND

[0002] The layered medium detection (such as the detection of the earth layered medium, the detection of the metal coating, etc.) currently has the traditional visual inspection, chemical analysis and other ways, and also has the non-destructive detection technology of the material and the structural part by using the sound, light, force, electromagnetic and other characteristics without damaging the applicability and usability of the detection target. At present, the ray, ultrasonic, magnetic powder, penetration and eddy current are widely used conventional detection technologies.

[0003] The electromagnetic detection technology has the advantages of non-contact, no pollution, low cost, simple operation and the like, and is widely used in detecting the electromagnetic parameter information of the medium at different depths. Since the impedance and the apparent resistivity data contain the electromagnetic field information in the layered medium, the present application fully mines the information contained in the apparent resistivity, and intends to provide a more advantageous layered medium detection scheme. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a layered medium detection method based on electromagnetic field, a storage medium and an electronic device, which fully mines the information in the data obtained by the electromagnetic detection technology, designs the "stripping impedance" method, effectively calculates the thickness and resistivity of each medium by stripping each layer of the detection target layer by layer, realizes the layered medium detection of the detection target, and has the advantages of non-contact, no pollution, low cost, simple operation, high speed and no need of coupling.

[0005] In order to achieve the above purpose, the embodiments of the present application are realized by the following ways:

[0006] In a first aspect, the embodiments of the present application provide a layered medium detection method based on electromagnetic field, comprising: obtaining the electric field data and the magnetic field data of a detection target; determining the impedance of the detection target based on the electric field data and the magnetic field data of the detection target; determining the apparent resistivity curve of the detection target based on the electric field data and the magnetic field data of the detection target; determining the resistivity value of the current first layer of the detection target based on the apparent resistivity; determining the thickness of the current first layer of the detection target based on the apparent resistivity curve of the detection target and the resistivity value of the current first layer; and performing the "impedance stripping" of the detection target layer by layer based on the resistivity value and the thickness of the current first layer, to determine the resistivity value and the thickness of each layer of the detection target.

[0007] In combination with the first aspect, in a first possible implementation manner of the first aspect, the impedance of the detection target is determined based on the electric field data and the magnetic field data of the detection target, comprising:

[0008] The impedance is calculated using the following equation:

[0009]

[0010] Or

[0011]

[0012] where Z is the impedance of the target to be measured, E is the electric field, E x is the horizontal electric field component of the electric field E in the x direction, E y is the horizontal electric field component of the electric field E in the y direction, H is the magnetic field, H x is the horizontal magnetic field component of the magnetic field H in the x direction, H y is the horizontal magnetic field component of the magnetic field H in the y direction.

[0013] In combination with the first aspect, in a second possible implementation manner of the first aspect, if the frequency is higher than 10 4 Hz, the apparent resistivity curve of the target to be measured is determined based on the electric field data and the magnetic field data of the target to be measured, including: the apparent resistivity is calculated using the following equation:

[0014]

[0015] where p s is the apparent resistivity, w is the angular frequency, m0 is the vacuum permeability, Z is the impedance, and imag represents the imaginary part.

[0016] In combination with the first aspect, in a third possible implementation manner of the first aspect, if the frequency is not higher than 10 4 Hz, the apparent resistivity curve of the target to be measured is determined based on the electric field data and the magnetic field data of the target to be measured, including:

[0017] The apparent resistivity is calculated using the following equation:

[0018]

[0019] where p s is the apparent resistivity, w is the angular frequency, m0 is the vacuum permeability, Z is the impedance, and imag represents the imaginary part.

[0020] Alternatively, the apparent resistivity is calculated using the following equation:

[0021]

[0022] where m0 is the vacuum permeability, w is the angular frequency, and Z is the impedance.

[0023] Based on the calculated apparent resistivity, the apparent resistivity curve of the target to be measured is determined.

[0024] In a fourth possible implementation manner of the first aspect, based on the apparent resistivity, the resistivity value of the current first layer medium of the target to be detected is determined, including:

[0025] determining whether the differences of the first three apparent resistivity data with the highest frequencies in the current apparent resistivity are within 1 ‰;

[0026] if yes, the apparent resistivity at the time with the highest frequency in the apparent resistivity is determined as the resistivity value of the current first layer medium of the target to be detected;

[0027] if no, the detection frequency range is expanded, the highest frequency of the detection frequency is adjusted to 10 times of the original, the electric field data and the magnetic field data of the target to be detected are updated, the impedance of the target to be detected is recalculated, a new apparent resistivity curve is determined, and the determination is continued until the resistivity value of the current first layer medium of the target to be detected is determined.

[0028] In a fifth possible implementation manner of the first aspect, based on the apparent resistivity curve of the target to be detected and the resistivity value of the current first layer medium, the thickness of the current first layer medium of the target to be detected is determined, including: determining the target point frequency of the resistivity value of the current first layer medium of the target to be detected and the apparent resistivity curve; and calculating the thickness of the current first layer medium of the target to be detected by using the following formula:

[0029]

[0030] wherein, h m is the thickness of the current first layer medium of the target to be detected, μ0 is the magnetic permeability of vacuum, f c is the target point frequency, and σ m is the resistivity value of the current first layer medium of the target to be detected.

[0031] In a sixth possible implementation manner of the first aspect, based on the resistivity value and the thickness of the current first layer medium, the target to be detected is subjected to layer-by-layer impedance stripping to determine the resistivity value and the thickness of each layer medium of the target to be detected, including:

[0032] S1: taking all the calculated resistivity value and thickness of the current first layer medium as known conditions, performing impedance stripping to obtain the impedance of the remaining part of the target to be detected;

[0033] S2: determining the apparent resistivity curve of the remaining part of the target to be detected;

[0034] S3: based on the apparent resistivity, determining the resistivity value of the current first layer medium of the remaining part of the target to be detected;

[0035] S4: determining the thickness of the current first layer medium of the remaining part of the target based on the apparent resistivity curve of the remaining part of the target and the resistivity value of the current first layer medium;

[0036] S5: cyclically performing steps S1-S4 until the resistivity value and the thickness of each layer medium of the target are solved.

[0037] With reference to the sixth possible implementation manner of the first aspect, in a seventh possible implementation manner of the first aspect,

[0038] In S1, the impedance of the remaining part of the target satisfies:

[0039]

[0040] wherein, Z m is the top surface impedance of the mth layer in the target, Z m+1 is the bottom surface impedance of the mth layer in the target, and is the top surface impedance of the m+1th layer in the target, m∈[1,N], N is the total number of layered media of the target, N≥2; Z 0m is the characteristic impedance of the mth layer, k m is the complex wave number of the mth layer, h m is the thickness of the mth layer.

[0041] In the second aspect, the embodiments of the present application provide a storage medium installed in a device, comprising a stored program, wherein when the program runs, the device in which the storage medium is located performs the layered medium detection method based on electromagnetic field in the first aspect or any one of the possible implementation manners of the first aspect.

[0042] In the third aspect, the embodiments of the present application provide an electronic device, comprising a memory and a processor, the memory is used to store information comprising program instructions, the processor is used to control the execution of the program instructions, and the program instructions are loaded and executed by the processor to realize the steps of the layered medium detection method based on electromagnetic field in the first aspect or any one of the possible implementation manners of the first aspect.

[0043] Advantageous effects:

[0044] 1. This scheme obtains the electric and magnetic field data of the target to determine its impedance and apparent resistivity curves. By mining the information in the apparent resistivity, the resistivity value of the first layer of medium on the target is determined, and the thickness of the first layer is further calculated. Then, based on the resistivity and thickness of the first layer, an impedance stripping process is performed layer by layer on the target to determine the resistivity and thickness of each layer of medium. By fully mining the information in the data obtained from electromagnetic detection technology, an "impedance stripping" method is designed. By stripping each layer of medium on the target, the thickness and resistivity of each layer are effectively calculated, enabling the detection of layered media on the target. This method has advantages such as non-contact, pollution-free, low cost, simple operation, high speed, and no coupling required.

[0045] 2. Considering the characteristics of different scenarios, such as in the field of geophysical electromagnetic exploration, where the frequency is relatively low (generally not exceeding 10), 4 (Hz), displacement current can be ignored, and the apparent resistivity of the uniform half-space model is equal to the resistivity of the half-space itself. Therefore, the following approach is adopted. Calculate apparent resistivity; however, for high-frequency scenarios (above 10), 4 For example, in the detection of metal coatings (Hz), where displacement current cannot be ignored, a new definition of apparent resistivity needs to be designed. Applicable to the entire frequency band, for a uniform half-space medium, its value is the resistivity of the uniform half-space (for media such as metals, because their resistivity is relatively small, the reciprocal of the apparent resistivity can be taken, and the apparent conductivity can be used for calculation). This allows this solution to be applied to a wider range of layered medium detection scenarios.

[0046] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of a layered medium.

[0049] Figure 2 This is a flowchart of a layered medium detection method based on electromagnetic fields.

[0050] Figure 3is a schematic view of apparent resistivity curves for a three-layer layered medium model.

[0051] Figure 4 is a flow chart of layer-by-layer impedance peeling for a target to be detected.

[0052] Figure 5 is a schematic view of apparent resistivity curves of the remaining part after one layer of impedance peeling for a three-layer layered medium model. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0054] To facilitate the understanding of the present application, the theoretical basis of the layered medium detection method based on electromagnetic field in the present application is deduced first in the present embodiment.

[0055] Medium: In the present embodiment, it refers to the target to be detected, such as a metal layered medium, an earth layered medium, an ice layered medium, etc.

[0056] Cagniard apparent resistivity: Cagniard apparent resistivity is proposed by L. Cagniard in 1953 and is used in magnetotelluric sounding. It is calculated by measuring impedance at different frequencies to reflect the electrical structure at different depths. The key point here is that impedance is a function of the electrical properties of the earth interior, and the relationship between frequency and detection depth.

[0057] All macroscopic electromagnetic phenomena satisfy Maxwell's equations, and the differential form is as follows:

[0058]

[0059] wherein, is the Hamiltonian operator, which is E is the electric field intensity, B is the magnetic induction intensity, D is the electric displacement, H is the magnetic field intensity, J is the current density, p is the free charge density, i is the imaginary part, and w is the angular frequency.

[0060] The three constitutive relations are:

[0061] D = εE, (5)

[0062] B = μH, (6)

[0063]

[0064] In the formula, the parameters ε, μ and σ are dielectric constant, magnetic permeability and conductivity, respectively, which indicates that the conductivity is a tensor.

[0065] As shown in Figure 1 ,Figure 1 A schematic diagram of layered medium.

[0066] Suppose the layered medium is composed of N horizontal layers, and the conductivity of each layer is:

[0067] σ1,σ2,…,σ N , (8)

[0068] The thickness of each layer is:

[0069] h1,h2,…,h N , (9)

[0070] Then, using the relationship between the impedance values at two different depths in the same layer and the continuity condition of impedance at the interface, the recursive formula of ground impedance (understood as the top surface impedance of the first layer medium) can be derived.

[0071] According to Maxwell's equations, take the time-harmonic factor e -iωt In any layer medium, we can get:

[0072]

[0073] In the formula, E x is the horizontal electric field component of the electric field E in the x direction, k m is the complex wave number of the mth layer, m∈[1,N], which satisfies:

[0074]

[0075] Here, the full frequency band is considered, the displacement current term is retained, μ0 is the vacuum permeability, σ m is the conductivity of the mth layer.

[0076] Then, the general solution of formula (10) is:

[0077]

[0078] Where z represents the depth, and A and B generally refer to constants.

[0079] Using the relationship between E x and H y , we can get:

[0080]

[0081] The impedance expression is:

[0082]

[0083] Take as the characteristic impedance of the mth layer, and assume that the top surface depth of the mth layer is z m, the bottom depth is z m+1 Then the impedance at these depths in the mth layer can be expressed as:

[0084]

[0085] By combining equation (15) and equation (16), we can get:

[0086]

[0087] Thus we can get:

[0088]

[0089] Let z m+1 -z m = h m , the thickness of the mth layer, and substitute it into equation (18), we can get:

[0090]

[0091] It can also be written as:

[0092]

[0093] Let:

[0094]

[0095] According to equation (20), we can get:

[0096]

[0097] Cagniard apparent resistivity is a commonly used parameter in magnetotelluric sounding (MT) to describe the resistivity distribution of the underground medium. It is calculated by measuring the horizontal electric field component (E x , E y ) and the vertical magnetic field component (H z ) of the natural electromagnetic field, and the formula is:

[0098]

[0099] where μ0 is the vacuum permeability, ω is the angular frequency, Z is the impedance, and satisfies:

[0100]

[0101] where E is the electric field, E x is the horizontal electric field component of the electric field E in the x direction, E y is the horizontal electric field component of the electric field E in the y direction, H is the magnetic field, and Hx Hx is a horizontal magnetic field component of the magnetic field H in the x direction. y Hy is a horizontal magnetic field component of the magnetic field H in the y direction.

[0102] The apparent resistivity defined by the above formula (23) is applicable to the field of geophysical electromagnetic exploration (displacement current can be ignored), and the value of the apparent resistivity of the homogeneous half-space model is equal to the resistivity value of the half-space. However, it is no longer applicable at high frequencies (when the displacement current cannot be ignored). Accordingly, for the full frequency band (low frequency to high frequency), the present embodiment proposes a new definition of apparent resistivity as follows:

[0103]

[0104] This definition is applicable to the full frequency band, and for a homogeneous half-space medium, the value is the resistivity value of the homogeneous half-space. If it is for a medium such as metal, because its resistivity is small, the apparent resistivity can also be taken as the reciprocal, and the apparent conductivity is used.

[0105] The above is the theoretical basis derivation process (derivation is performed by taking a plane wave as an example), which is a derivation scheme based on resistivity. Based on the same concept, the derivation process can also be applicable to a derivation scheme based on conductivity (reciprocal of resistivity). Therefore, the protection scope of the present concept should include the scheme based on resistivity and the scheme based on conductivity. The present embodiment is introduced by taking resistivity as an example, and the scheme based on conductivity is similar (the formula form is slightly different), which should not be considered as a limitation of the present application.

[0106] Accordingly, the present embodiment provides a layered medium detection method based on electromagnetic field, applied to electronic equipment (such as computers, servers, etc.). Please refer to Figure 2 , Figure 2 The layered medium detection method based on electromagnetic field is a flowchart.

[0107] In the present embodiment, the layered medium detection method based on electromagnetic field can include steps S10, S20, S30, S40, S50, and S60.

[0108] When detecting the layered medium (the purpose of detection is to determine the resistivity value and thickness of each layered medium of the target to be measured), first, the electronic equipment can run step S10.

[0109] Step S10: Obtain the electric field data and magnetic field data of the target to be measured.

[0110] In the present embodiment, the electronic equipment can obtain the electric field data and magnetic field data of the target to be measured. The electric field data includes the electric field E, and the magnetic field data includes the magnetic field H.

[0111] After obtaining the electric field data and the magnetic field data of the target to be detected, the electronic device can execute step S20.

[0112] Step S20: determining the impedance of the target to be detected based on the electric field data and the magnetic field data of the target to be detected.

[0113] In the present embodiment, since the theoretical derivation process has been introduced above, the determination of the impedance of the target to be detected will not be repeated here. The impedance of the target to be detected is mainly calculated by using formula (24), that is, the impedance is calculated by using the following formula:

[0114]

[0115] or

[0116]

[0117] wherein Z is the impedance of the target to be detected, E is the electric field, E x is the horizontal electric field component of the electric field E in the x direction, E y is the horizontal electric field component of the electric field E in the y direction, H is the magnetic field, H x is the horizontal magnetic field component of the magnetic field H in the x direction, H y is the horizontal magnetic field component of the magnetic field H in the y direction.

[0118] After that, the electronic device can execute step S30.

[0119] Step S30: determining the apparent resistivity curve of the target to be detected based on the electric field data and the magnetic field data of the target to be detected.

[0120] In the present embodiment, the electronic device can determine the apparent resistivity according to the detection scene by using a corresponding scheme, which is described in the foregoing formula (23)-(25).

[0121] If the frequency is higher than 10 4 Hz (such as the scene of coating detection), the displacement current cannot be ignored, and then the apparent resistivity calculation scheme of formula (25) is used, that is:

[0122] The apparent resistivity is calculated by using the following formula:

[0123]

[0124] wherein p s is the apparent resistivity, w is the angular frequency, m0 is the vacuum permeability, Z is the impedance, and imag represents the imaginary part.

[0125] If the frequency does not exceed 10 4 Hz, the apparent resistivity can be calculated by using formula (28), and the apparent resistivity calculation scheme of formula (23) can also be used, that is:

[0126] The apparent resistivity is calculated using the following formula:

[0127]

[0128] Where, ρ s ω is the apparent resistivity, μ0 is the angular frequency, and Z is the impedance.

[0129] Based on this, the apparent resistivity curve of the target under test can be determined (generally arranged from high to low frequency to form an apparent resistivity curve).

[0130] For ease of understanding, a three-layered medium model (i.e.) will be used. Figure 1 Taking the model shown as an example, the model parameters are: resistivity of the three layers of medium is 100 Ω·m, 10 Ω·m, and 200 Ω·m, and thickness of the three layers of medium is 1000 m, 800 m, and a uniform half-space, respectively. It should be noted that before detection, it is not necessary to know the number of layers of the layered medium of the target object, nor is it known the resistivity and thickness of each layer of the layered medium. The purpose of detection is to determine the resistivity and thickness of each layer of the layered medium. The determined apparent resistivity curve is as follows: Figure 3 As shown.

[0131] After obtaining the apparent resistivity curve of the target under test, the electronic device can run step S40.

[0132] Step S40: Determine the resistivity value of the current first layer of medium of the target under test based on the apparent resistivity.

[0133] Considering that when the frequency is sufficiently high, the value of the apparent resistivity curve is the resistivity value of the first layer of dielectric material, the resistivity value of the first layer of dielectric material can be directly obtained from the apparent resistivity data. In this embodiment, the electronic device can determine whether the difference between the three highest-frequency apparent resistivity data in the current apparent resistivity data is within 1‰.

[0134] If the conditions are met, the apparent resistivity at the highest frequency is determined to be the resistivity value of the current first layer of medium of the target under test.

[0135] Otherwise, expand the detection frequency range by adjusting the highest frequency to 10 times the original frequency (for example, if the highest frequency at the beginning of detection is 100Hz and gradually decreases, then adjust it once to increase the highest frequency by 10 times, starting from 1000Hz and gradually decreasing, while the lowest frequency remains unchanged, thus expanding the detection frequency range), update the electric field and magnetic field data of the target under test, recalculate the impedance of the target under test, determine the new apparent resistivity curve, and continue to judge until the resistivity value of the current first layer of medium of the target under test is determined.

[0136] Continuing with the example above, the resistivity ρ1 of the first dielectric layer is 99.9992753161281 Ω·m.

[0137] Once the resistivity value is determined, the electronic device can proceed to step S50.

[0138] Step S50: Based on the apparent resistivity curve of the target under test and the resistivity value of the current first layer of medium, determine the thickness of the current first layer of medium of the target under test.

[0139] In this embodiment, the electronic device can determine the resistivity value of the current first layer of the medium of the target under test and the target point frequency f of the apparent resistivity curve. c Then, the thickness of the first layer of medium of the target under test is calculated using the following formula:

[0140]

[0141] Among them, h m Let μ be the thickness of the first layer of medium of the target object, μ0 be the vacuum permeability, and f be the density of the first layer. c For the target point frequency, σ m The resistivity value of the first layer of medium of the target under test.

[0142] It should be noted that formula (30) here is from the applicant's patent document: Seawater Depth Detection Method, Storage Medium and Electronic Device Based on Electromagnetic Field (patent application number 2024101143877). Its principle and derivation process are similar (although the scenarios are different; the patent document is for seawater depth detection, while this solution is for layered medium thickness detection, the method and formula derivation are consistent when determining the thickness. This document can be consulted. However, for the target point frequency, this paper uses the first target point frequency). Figure 3 (The location marked with an asterisk) indicates the position of the first dielectric layer. The conclusion is quoted directly here without further elaboration. Based on this, the resistivity σ of the first dielectric layer can be determined. m and target point frequency f c Based on this, the thickness h of the current first layer of medium is calculated. m .

[0143] Continuing with the previous example, locate the apparent resistivity curve and the resistivity value of the first layer ( Figure 3 The point where the half-space line begins to separate from the high-frequency to the low-frequency direction, such as... Figure 3 The * point in the diagram determines the target frequency f at the separation point. c= 140.420857594656 Hz, and then the thickness is calculated by using the formula (30), and the thickness h1 of the first layer of the layered medium is 1000.72300482668 m. At this time, the resistivity value p1 and the depth value h1 of the first layer of the layered medium are determined.

[0144] The resistivity value p1 and the depth value h1 of the first layer of the layered medium are determined. m and the thickness h m After that, the impedance stripping can be performed, and the determined part can be stripped, and the resistivity value p m and the thickness h m At this time, the electronic device can perform step S60.

[0145] Step S60: Based on the resistivity value and the thickness of the current first layer of the medium, the impedance stripping of the target to be measured is performed layer by layer, and the resistivity value and the thickness of each layer of the target to be measured are determined.

[0146] In this embodiment, based on the determined part (the resistivity value and the thickness of the current first layer of the medium), the impedance stripping of the target to be measured can be performed. As shown in Figure 4 , a flowchart for performing the impedance stripping of the target to be measured layer by layer is shown. Figure 4

[0147] In this embodiment, the impedance stripping can include S1, S2, S3, S4, and S5.

[0148] When the impedance stripping is performed, S1 is first performed.

[0149] S1: The impedance stripping is performed based on all the calculated resistivity value and thickness of the current first layer of the medium as known conditions, and the impedance of the remaining part of the target to be measured is obtained.

[0150] In this embodiment, the key of the impedance stripping is that after the thickness and the resistivity value of the layer of the layered medium are determined, the impedance formula (formula (22)) can be used to strip the determined layered medium, and the remaining part of the target to be measured is obtained. Because the thickness and the resistivity value of the first layer are obtained, the formula can be used to determine the expression of the next layer, and the resistivity value and the thickness of the next layer are calculated, and the impedance stripping is realized.

[0151] Specifically, the impedance form of the remaining part of the target to be measured is given as follows: the impedance of the remaining part of the target to be measured satisfies:

[0152]

[0153] wherein Z m is the top surface impedance of the mth layer of the target to be measured, and Z m+1 ​Zm is the bottom surface impedance of the mth layer in the target to be measured, and is also the top surface impedance of the m+1th layer in the target to be measured, m [1, N], N is the total number of layered media of the target to be measured, N 2; Zm is the characteristic impedance of the mth layer, 0m Zm is the characteristic impedance of the mth layer, k m Zm is the complex wave number of the mth layer, h m Zm is the thickness of the mth layer.

[0154] It should be noted that formula (31) discloses the expression of the impedance of the layered medium, which can be peeled off layer by layer according to the determined layered medium part, and the impedance of the remaining part of the target to be measured can be calculated by formula (31) each time. When each layered medium of the target to be measured is not determined, the impedance of the first layered medium is also undetermined (because the thickness of the first layered medium has not been calculated), and the "impedance peeling" cannot be performed temporarily. However, the impedance of the whole target to be measured (that is, formula (24)) is determined. The relationship between the "impedance peeling" method and the electric field and magnetic field is established by using the impedance (the impedance of formula (22) and the impedance of formula (24) are the same concept, but two different expressions are needed in this paper), so that the present scheme has feasibility.

[0155] On this basis, the electronic device can run S2.

[0156] S2: Determine the apparent resistivity curve of the remaining part of the target to be measured.

[0157] In this embodiment, the way to determine the apparent resistivity curve of the remaining part of the target to be measured is similar to the foregoing (but the impedance of the formula is the impedance of the remaining part of the target to be measured after the calculated layered medium part is peeled off), please refer to the foregoing introduction, which will not be repeated here.

[0158] Continuing the foregoing example, since the first layer of the three-layer layered medium model has been "impedance peeled", the apparent resistivity curve obtained at this time is as shown in Figure 5 .

[0159] After obtaining the apparent resistivity curve of the remaining part of the target to be measured, the electronic device can run S3.

[0160] S3: Based on the apparent resistivity, determine the resistivity value of the current first layer medium of the remaining part of the target to be measured.

[0161] Since the "impedance peeling" has been performed, the first layer of the remaining part of the target to be measured can still determine the resistivity value of the layered medium of this layer based on the apparent resistivity data in the apparent resistivity curve at this time.

[0162] Then, the electronic device runs S4.

[0163] S4: determining the thickness of the current first layer medium of the remaining part of the target based on the apparent resistivity curve of the remaining part of the target and the resistivity value of the current first layer medium.

[0164] The determination process of the thickness is described above and will not be repeated here. Continuing the example above, the target point frequency at this time is determined from the apparent resistivity curve of the remaining part of the target, and then the resistivity value of the layer and the target point frequency are brought into formula (30) to obtain the thickness of the layered medium of the layer. Figure 5 Accordingly, the detection of the layered medium of the layer is completed, and the electronic device can continue to operate until the detection of the layered medium of the entire target is completed.

[0165] S5: cyclically operating steps S1-S4 until the resistivity value and the thickness of each layer medium of the target are solved.

[0166] In this embodiment, the electronic device can cyclically operate steps S1-S4 until the resistivity value and the thickness of each layer medium of the target are solved (the last layer is a uniform half-space).

[0167] Finally, the layered medium detection of the target can be realized, and the data (resistivity, thickness, etc.) of the layered medium obtained by the detection can be used for further interpretation and application, which will not be repeated here.

[0168] This embodiment also provides a storage medium installed in an electronic device, including a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the layered medium detection method based on electromagnetic field of this embodiment.

[0169] In addition, this embodiment also provides an electronic device including a memory and a processor, the memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions, and the program instructions loaded and executed by the processor realize the steps of the layered medium detection method based on electromagnetic field of this embodiment.

[0170]

[0171] ​In summary, the embodiment of the present application provides a layered medium detection method based on electromagnetic field, a storage medium and an electronic device. The present scheme determines the impedance and apparent resistivity curve of the target to be detected by obtaining the electric field data and magnetic field data of the target to be detected. The resistivity value of the current first layer medium of the target to be detected is determined by mining the information in the apparent resistivity, and the thickness of the current first layer medium of the target to be detected is further calculated. Then, the target to be detected is peeled off layer by layer based on the resistivity value and thickness of the current first layer medium, and the resistivity value and thickness of each layer of the target to be detected are determined accordingly. By fully mining the information in the data obtained by the electromagnetic detection technology, the "peeling impedance" method is designed, and the thickness and resistivity of each layer of medium are effectively calculated by peeling off each layer of medium of the detection target layer by layer, so that the layered medium detection of the detection target is realized, and the advantages of non-contact, non-pollution, low cost, simple operation, high speed and no need of coupling are achieved.

[0172] For different scenarios, for example, in the field of geophysical electromagnetic exploration, because the frequency is relatively low (generally not more than 10 4 Hz), the displacement current can be ignored, and the value of the apparent resistivity of the uniform half-space model is equal to the resistivity value of the half-space, so the apparent resistivity is calculated. For high-frequency scenarios (more than 10 4 Hz), such as metal coating detection, the displacement current cannot be ignored, and a new definition of apparent resistivity is designed, which is applicable to the full frequency band. For a uniform half-space medium, its value is the resistivity value of the uniform half-space (if it is for a medium such as metal, because its resistivity is small, the apparent resistivity can also be taken as the inverse, and the apparent conductivity is used for calculation). In this way, the present scheme can be applied to a wider range of layered medium detection scenarios.

[0173] In this document, relational terms such as first and second and the like can only be used to distinguish one entity or action from another entity or action, without necessarily requiring or implying that these entities or actions are in any way mutually exclusive, unless the context clearly indicates otherwise.

[0174] The above merely provides an embodiment of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting layered media based on electromagnetic fields, characterized in that, include: Acquire the electric and magnetic field data of the target object; Based on the electric field and magnetic field data of the target, the impedance of the target is determined. Based on the electric field and magnetic field data of the target, the apparent resistivity curve of the target is determined. Based on apparent resistivity, the resistivity value of the first layer of medium of the target under test is determined. Based on the apparent resistivity curve of the target under test and the resistivity value of the current first layer of medium, the thickness of the current first layer of medium of the target under test is determined. Based on the resistivity and thickness of the first layer of medium, the target under test is subjected to layer-by-layer "impedance stripping" to determine the resistivity and thickness of each layer of medium of the target under test. Based on the resistivity and thickness of the first layer of medium, an impedance stripping process is performed layer by layer on the target under test to determine the resistivity and thickness of each layer of medium, including: S1: Using all the calculated resistivity and thickness of the current first layer of medium as known conditions, perform impedance stripping to obtain the impedance of the remaining part of the target under test; S2: Determine the apparent resistivity curve of the remaining part of the target to be measured; S3: Based on apparent resistivity, determine the resistivity value of the current first layer of medium in the remaining part of the target under test; S4: Based on the apparent resistivity curve of the remaining part of the target under test and the resistivity value of the current first layer of medium, determine the thickness of the current first layer of medium of the remaining part of the target under test. S5: Repeat steps S1 to S4 until the resistivity and thickness of each layer of the medium of the target under test are obtained. In S1: The impedance of the remaining part of the target under test satisfies: Among them, Z m Z represents the impedance of the top surface of the m-th layer in the target under test. m+1 Z represents the bottom impedance of the m-th layer in the target under test, and also the top impedance of the (m+1)-th layer in the target under test, where m∈[1,N], and N is the total number of layers in the layered medium of the target under test, N≥2; 0m Let be the characteristic impedance of the m-th layer. k m h is the complex wave number of the m-th layer. m Let be the thickness of the m-th layer.

2. The method for detecting layered media based on electromagnetic fields according to claim 1, characterized in that, Based on the electric and magnetic field data of the target object, the impedance of the target object is determined, including: The impedance is calculated using the following formula: or Where Z is the impedance of the target object, E is the electric field, and E x Let E be the horizontal electric field component of the electric field E in the x-direction. y Let E be the horizontal electric field component in the y-direction, and H be the magnetic field. x Let H be the horizontal magnetic field component of the magnetic field H in the x-direction. y Let H be the horizontal magnetic field component of the magnetic field H in the y direction.

3. The method for detecting layered media based on electromagnetic fields according to claim 1, characterized in that, If the frequency is higher than 10 4 Based on the electric and magnetic field data of the target, the apparent resistivity curve of the target is determined, including: The apparent resistivity is calculated using the following formula: Where, ρ s ω is the apparent resistivity, μ0 is the angular frequency, Z is the permeability of free space, and imag indicates taking the imaginary part; Based on the calculated apparent resistivity, the apparent resistivity curve of the target under test is determined.

4. The method for detecting layered media based on electromagnetic fields according to claim 1, characterized in that, If the frequency is not higher than 10 4 Based on the electric and magnetic field data of the target, the apparent resistivity curve of the target is determined, including: The apparent resistivity is calculated using the following formula: Where, ρ s ω is the apparent resistivity, μ0 is the angular frequency, Z is the permeability of free space, and imag indicates taking the imaginary part; Alternatively, the apparent resistivity can be calculated using the following formula: Where μ0 is the free permeability, ω is the angular frequency, and Z is the impedance; Based on the calculated apparent resistivity, the apparent resistivity curve of the target under test is determined.

5. The method for detecting layered media based on electromagnetic fields according to claim 1, characterized in that, Based on apparent resistivity, the resistivity value of the current first layer of medium of the target under test is determined, including: Determine whether the difference between the three most frequent apparent resistivity data in the current apparent resistivity is within 1‰; If so, determine the resistivity of the first layer of medium of the target under test as the resistivity value at the highest frequency in the apparent resistivity. If not, expand the detection frequency range, adjust the highest detection frequency to 10 times the original, update the electric field and magnetic field data of the target under test, recalculate the impedance of the target under test, determine the new apparent resistivity curve, and continue to judge until the resistivity value of the current first layer of medium of the target under test is determined.

6. The method for detecting layered media based on electromagnetic fields according to claim 1, characterized in that, Based on the apparent resistivity curve of the target under test and the resistivity value of the current first layer of medium, the thickness of the current first layer of medium of the target under test is determined, including: Determine the resistivity value of the first layer of medium of the target under test and the target point frequency of the apparent resistivity curve; The thickness of the first layer of medium of the target under test is calculated using the following formula: Among them, h m Let μ be the thickness of the first layer of medium of the target object, μ0 be the vacuum permeability, and f be the density of the first layer. c For the target point frequency, σ m The resistivity value of the first layer of medium of the target under test.

7. A storage medium, characterized in that, The storage medium is installed within the device and includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the layered medium detection method based on any one of claims 1 to 6.

8. An electronic device comprising a memory and a processor, the memory for storing information including program instructions, and the processor for controlling the execution of the program instructions, characterized in that: When the program instructions are loaded and executed by the processor, they implement the steps of the layered medium detection method based on electromagnetic fields as described in any one of claims 1 to 6.

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