A method and device for evaluating the detection capability of a frequency domain electrical source induced electromagnetic method

Abstract

This invention discloses a method and apparatus for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method. The method includes: generating an electrical model based on the electrical structural characteristics of the exploration area; using the electrical model to perform forward modeling based on preset emission and observation parameters to simulate the vertical magnetic field components of each excitation source at each observation point, as well as the electric or magnetic field components to be evaluated; for each excitation source, determining the virtual ratio of the vertical magnetic field at each observation point based on the vertical magnetic field components, where the virtual ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field; determining the detection illumination at each observation point based on the amplitude of the electric or magnetic field components, the virtual ratio, a preset virtual ratio benchmark, and preset background noise parameters; and summing the detection illumination of each excitation source at each observation point to obtain the total illumination at each observation point. This method can accurately evaluate the detection capability of multi-source coverage areas and has strong applicability.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration technology, and in particular to a method and apparatus for evaluating the detection capability of frequency-domain electric source induction electromagnetic method. Background Technology

[0002] Frequency-domain electric source induction electromagnetic method is an electromagnetic exploration method that uses a grounded conductor source to excite the ground with harmonics of multiple frequencies. The electric or magnetic fields are received at a certain distance on the ground, and the distribution and variation characteristics of the electromagnetic field are studied to investigate the distribution characteristics of the earth's resistivity, thereby solving related geological problems. This method has been widely used in energy, mineral, and hydrological exploration. Multi-directional multi-field source frequency-domain electric source induction electromagnetic method uses multiple field sources to cover the detection area multiple times from multiple angles.

[0003] The electromagnetic field observed by the frequency domain electromagnetic method is the total field, which includes the primary field related to the emission and the secondary field generated by the earth's induction. When the measuring point is close to the emission source, the primary field accounts for a higher proportion, and the conduction effect is dominant; while when the measuring point is far from the emission source, the proportion of the secondary field increases, that is, the proportion of the induction effect increases.

[0004] Frequency-domain electric source induction electromagnetic method is based on the principle of electromagnetic induction for exploration. Therefore, the observation area needs to be a certain distance from the transmitter to ensure that the induced secondary field reaches a certain proportion. When designing the observation area, a minimum distance from the transmitter (minimum transmit / receive distance) needs to be set. When performing inversion interpretation based on impedance, observations in the far-field area are required, and the minimum transmit / receive distance needs to be set relatively large (generally 3 times the exploration depth). However, when performing inversion interpretation based on electromagnetic field components, the minimum transmit / receive distance can be set smaller (generally not less than 1 times the exploration depth). On the other hand, the intensity of the electromagnetic field attenuates rapidly with the transmit / receive distance (distance from the receiver to the transmitter). When it attenuates below the background noise, it cannot be accurately observed. The farthest distance at which a reliable signal can be observed is called the maximum transmit / receive distance. The area between the minimum transmit / receive distance and the maximum transmit / receive distance covered by the transmitter is the detectable area.

[0005] Artificial source electromagnetic fields possess highly complex wavefield characteristics, and various unfavorable factors affect exploration results, such as volume effects, static displacement effects, source effects, copying effects, and shadowing effects. Studies have found that compared to inversion interpretation using single-source data, joint inversion interpretation using multi-directional, multi-source data can effectively eliminate or suppress these effects, significantly improving the interpretation results. Therefore, multi-directional, multi-source electromagnetic methods are an important direction and a current research hotspot in electromagnetic exploration. However, for the acquisition of multi-directional, multi-source frequency-domain electric source ground electromagnetic data, there is still a lack of a method to evaluate the detection capability of the multi-directional, multi-source coverage area to guide the rational deployment of the sources. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide a method and apparatus for evaluating the detection capability of frequency domain electric source induction electromagnetic method to overcome or at least partially solve the above problems, which can evaluate the detection capability of multi-directional multi-field source coverage area.

[0007] This invention provides a method for evaluating the detection capability of frequency-domain electrical source inductive electromagnetic method, comprising:

[0008] Based on the electrical structural characteristics of the exploration area, an electrical model of the exploration area is generated;

[0009] Based on the preset emission parameters and observation parameters, the electrical model is used to perform forward modeling to simulate the observation components of each excitation source at each observation point. The observation components include the vertical magnetic field component and the electric or magnetic field component to be evaluated.

[0010] For each excitation source, the virtual ratio of the vertical magnetic field at each observation point is determined based on the vertical magnetic field component at each observation point. The virtual ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field. The detection illumination at each observation point is determined based on the amplitude of the electric or magnetic field component to be evaluated, the virtual ratio, the preset virtual ratio benchmark, and the preset background noise parameters.

[0011] The total illumination at each observation point is obtained by summing the detection illumination of each excitation source at each observation point.

[0012] The detectable area is determined based on the total illuminance and the preset illuminance threshold.

[0013] In some optional embodiments, generating an electrical model of the exploration area based on its electrical structural characteristics includes:

[0014] Based on the earth resistivity of the exploration area, an electrical model characterizing the earth resistivity distribution is generated; the electrical model is at least one of a three-dimensional model, a two-dimensional model, a uniform half-space model, and a layered half-space model.

[0015] In some optional embodiments, the emission parameters include emission source parameters and emission source excitation parameters; the emission source parameters include emission source position and emission source length; the emission source excitation parameters include excitation current and emission frequency;

[0016] The observation parameters include the receiver location and the observation components; the observation components include the vertical magnetic field component and the observation components to be evaluated.

[0017] In some optional embodiments, the step of using the electrical model to perform forward modeling to calculate the observation components of each excitation source at each observation point based on preset emission and observation parameters includes:

[0018] If the electrical model is a three-dimensional model, the observation components of each excitation source at each observation point are simulated using the three-dimensional forward modeling method;

[0019] If the electrical model is a two-dimensional model, the observation components of each excitation source at each observation point are simulated using the two-dimensional forward modeling method.

[0020] If the electrical model is a uniform half-space model or a layered half-space model, the one-dimensional forward modeling method is used to simulate the observed components of each excitation source at each observation point.

[0021] In some optional embodiments, determining the illumination intensity of each observation point based on the amplitude of the electric or magnetic field component to be evaluated, the virtual vibration ratio, a preset virtual vibration ratio benchmark, and preset background noise parameters includes:

[0022] It determines whether the amplitude of the electric or magnetic field component to be evaluated at the observation point is greater than the preset background noise threshold, and whether the virtual vibration ratio of the observation point is greater than or equal to the preset virtual vibration ratio benchmark.

[0023] If both are true, then the illumination of the observation point is determined to be the first specified value; otherwise, the illumination of the observation point is determined to be the second specified value.

[0024] In some alternative embodiments, a virtual vibration ratio benchmark is set for the exploration area; or different virtual vibration ratio benchmarks are set for observation areas at different distances in the exploration area according to the differences in the distance of the observation areas.

[0025] The virtual vibration ratio reference value ranges from 0.15 to 0.7; where the value is 0.7 for far-field observations and 0.15 for near-field observations, and 0.15-0.7 is the value range for the transition zone.

[0026] In some alternative embodiments, the above also includes:

[0027] The detection depth of the detectable area is determined based on the average resistivity and electromagnetic field frequency of the detection area.

[0028] In some alternative embodiments, the detection depth H of the detectable area is determined using the following formula:

[0029]

[0030] Where Rho is the average resistivity of the exploration area, and f is the frequency of the electromagnetic field.

[0031] This invention provides a device for evaluating the detection capability of frequency-domain electrical source inductive electromagnetic method, comprising:

[0032] The model building module is used to generate an electrical model of the exploration area based on its electrical structural characteristics.

[0033] The forward modeling module is used to perform forward modeling of the observation components of each excitation source at each observation point based on preset emission parameters and observation parameters using the electrical model. The observation components include the vertical magnetic field component and the observation components to be evaluated.

[0034] The illumination determination module is used to determine the virtual ratio of the vertical magnetic field at each observation point for each excitation source, based on the vertical magnetic field at each observation point. The virtual ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field. Based on the amplitude of the electric or magnetic field component to be evaluated at each observation point, the virtual ratio, a preset virtual ratio benchmark, and preset background noise parameters, the module determines the detection illumination at each observation point. The detection illumination of each excitation source at each observation point is accumulated to obtain the total illumination at each observation point.

[0035] The detection capability evaluation module is used to determine the detectable area based on the total illumination and the preset illumination threshold.

[0036] This invention provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the aforementioned frequency-domain electrical source induction electromagnetic detection capability evaluation method.

[0037] This invention provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method.

[0038] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0039] The frequency-domain electrical source induction electromagnetic method detection capability evaluation method provided in this invention generates an electrical model of the exploration area based on the electrical structural characteristics of the exploration area. Then, using the electrical model, forward modeling is performed to obtain the vertical magnetic field components of each excitation source at each observation point and the observation components to be evaluated. Based on the simulation results, the virtual vibration ratio of the vertical magnetic field at each observation point is determined. Furthermore, based on the virtual vibration ratio and the amplitude of the components to be evaluated, the detection illumination is determined. The detection capability of a single-source or multi-source coverage area is determined based on the detection illumination. This method can accurately determine the illumination after excitation by the excitation source and accurately evaluate the detection capability of multiple field sources. It is applicable to the detection capability evaluation of multiple excitation sources in multiple directions as well as the detection capability evaluation of a single excitation source, demonstrating strong applicability.

[0040] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0041] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0042] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0043] Figure 1 This is a flowchart of the frequency domain electrical source induction electromagnetic method detection capability evaluation method in an embodiment of the present invention.

[0044] Figure 2 This is a flowchart illustrating a specific implementation of the frequency-domain electrical source induction electromagnetic method for evaluating detection capability in an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the excitation source location for single-source excitation in an embodiment of the present invention.

[0046] Figure 4 This is a plane diagram of the amplitude of the electric field Ex excited by a single source in an embodiment of the present invention.

[0047] Figure 5 This is an illumination plan view of the single-source excited electric field Ex in an embodiment of the present invention.

[0048] Figure 6 This is a schematic diagram of the excitation source positions for bidirectional 2-source excitation in an embodiment of the present invention.

[0049] Figure 7 This is an amplitude plane diagram of the electric field Ex of the first excitation source excited by two bidirectional 2-source excitation in an embodiment of the present invention.

[0050] Figure 8 This is the second amplitude plane diagram of the electric field Ex of the second excitation source excited by two bidirectional sources in an embodiment of the present invention.

[0051] Figure 9 This is an illumination plan view of the electric field Ex excited by two sources in both directions in an embodiment of the present invention.

[0052] Figure 10 This is a schematic diagram of the excitation source positions for four-source excitation at four different locations in an embodiment of the present invention.

[0053] Figure 11This is a plane diagram of the electric field Ex of the first excitation source in the four-source excitation at four positions in this embodiment of the invention.

[0054] Figure 12 This is the second amplitude planar diagram of the electric field Ex of the second excitation source excited by four sources in four directions in an embodiment of the present invention.

[0055] Figure 13 This is a plane diagram of the electric field Ex of the third excitation source in the four-source excitation at four positions in this embodiment of the invention.

[0056] Figure 14 This is the second amplitude planar diagram of the electric field Ex of the fourth excitation source excited by four sources in four directions in an embodiment of the present invention.

[0057] Figure 15 This is an illumination plan view of the electric field Ex excited by four sources in four directions in an embodiment of the present invention.

[0058] Figure 16 This is a schematic diagram of the structure of the frequency domain electrical source induction electromagnetic method detection capability evaluation device in an embodiment of the present invention. Detailed Implementation

[0059] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0060] To address the problem that the detection capability of the field source coverage area cannot be evaluated when using ground electromagnetic exploration with multiple frequency domain electric sources from multiple directions, this invention proposes a method for calculating "illuminance" to evaluate the detection capability of the field source coverage area.

[0061] Illumination analysis in seismic exploration methods studies the detection capability of an acquisition system on subsurface structures using simulation methods, given the underlying geological background. The impact on target illumination mainly involves factors such as the observation system, overlying geological structure, and target dip angle. This invention, referencing the "illumination" analysis method in seismic exploration, proposes a method for evaluating the detection capability of the frequency-domain electric source inductive electromagnetic method (FMEM). This method evaluates the detection capability of the FMEM over the source-covered area by calculating the illumination intensity of the FMEM over the source-covered area. This method can be used to evaluate the detection capability of a single-azimuth, single-source system as well as multi-azimuth, multi-source systems.

[0062] This invention provides a method for evaluating the detection capability of frequency-domain electrical source induced electromagnetic method. This method is applicable to scenarios with a single excitation source, as well as scenarios with multiple excitation sources from multiple directions, and is particularly suitable for scenarios with multiple field sources from multiple directions. The method flow is as follows: Figure 1 As shown, it includes the following steps:

[0063] Step S101: Generate an electrical model of the exploration area based on its electrical structural characteristics.

[0064] In this step, referencing the electrical structure characteristics of the exploration area, an electrical model for forward modeling can be designed. This model can be a distribution model of the earth's resistivity, and for simplicity, it can be a uniform half-space model or a layered half-space model. The electrical structure characteristics of the exploration area can include resistivity data from different regions or locations within the exploration area.

[0065] In other words, in this step, an electrical model characterizing the distribution of earth resistivity can be generated based on the earth resistivity of the exploration area; wherein, the electrical model is at least one of a three-dimensional model, a two-dimensional model, a uniform half-space model, and a layered half-space model.

[0066] Step S102: Based on the preset emission parameters and observation parameters, use the electrical model to perform forward modeling to simulate the observation components of each excitation source at each observation point. The observation components include the vertical magnetic field component and the electric or magnetic field component to be evaluated.

[0067] The emission parameters include the emission source parameters and the emission source excitation parameters; the emission source parameters include the emission source position and the emission source length; the emission source excitation parameters include the excitation current and the emission frequency.

[0068] The observation parameters include the receiver location and the observation components; the observation components include the vertical magnetic field component and the electric or magnetic field component to be evaluated. The vertical magnetic field component is used when calculating the virtual vibration ratio. The component to be evaluated can be the vertical magnetic field component, other magnetic field components, or electric field components.

[0069] When performing forward modeling, different simulation methods can be used depending on the model:

[0070] If the electrical model is a three-dimensional model, the three-dimensional forward modeling method is used to simulate the observed components of each excitation source at each observation point, including the vertical magnetic field component and the electric or magnetic field component that needs to be evaluated.

[0071] If the electrical model is a two-dimensional model, the two-dimensional forward modeling method is used to simulate the observed components of each excitation source at each observation point, including the vertical magnetic field component and the electric or magnetic field component that needs to be evaluated.

[0072] If the electrical model is a uniform half-space model or a layered half-space model, the one-dimensional forward modeling method is used to simulate the observed components of each excitation source at each observation point, including the vertical magnetic field component and the electric or magnetic field component that needs to be evaluated.

[0073] Step S103: For each excitation source, determine the virtual vibration ratio of the vertical magnetic field at each observation point based on the vertical magnetic field components at each observation point. The virtual vibration ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field.

[0074] For each excitation source, the ratio of the imaginary part of the vertical magnetic field to the amplitude at each observation point can be calculated to obtain the virtual ratio R:

[0075]

[0076] Where R represents the virtual vibration ratio, Imag represents the imaginary part of the vertical magnetic field component, and Amp represents the amplitude of the vertical magnetic field.

[0077] Step S104: Determine the detection illumination of each observation point based on the amplitude of the electric or magnetic field component to be evaluated, the virtual vibration ratio, the preset virtual vibration ratio benchmark, and the preset background noise parameters.

[0078] Optionally, a virtual vibration ratio benchmark can be preset, which can be set for the exploration area; or different virtual vibration ratio benchmarks can be set for observation areas at different distances in the exploration area according to the difference in the distance of the observation area; the virtual vibration ratio benchmark value range is 0.15 to 0.7; among which, the value is 0.7 for observation in the far area, and 0.15 for observation in the near area, and 0.15-0.7 is the value range of the transition zone.

[0079] The virtual vibration ratio benchmark can be designed according to the needs of the inversion interpretation method. The virtual vibration ratio benchmark of the vertical magnetic field can be set based on the design of far-field or near-field observation. When observing in the far-field, the benchmark can be set to be equal to or greater than 0.7, and when observing in the near-field, the benchmark can be set to be equal to or greater than 0.15. Alternatively, a value between 0.15 and 0.7 can be taken as the virtual vibration ratio benchmark.

[0080] Optionally, background noise parameters can be preset. The background noise parameters are set according to the observation needs. Under normal circumstances, electric or magnetic fields higher than the background noise can be reliably observed.

[0081] In this step, it is determined whether the amplitude of the electric field or magnetic field component at the observation point is greater than the preset background noise threshold, and whether the virtual vibration ratio of the observation point is greater than or equal to the preset virtual vibration ratio benchmark; if both are true, the illumination of the observation point is determined to be the first specified value; otherwise, the illumination of the observation point is determined to be the second specified value.

[0082] The first specified value can be, for example, 1, and the second specified value can be, for example, 0. When the amplitude of the magnetic field component at the observation point is greater than a preset background noise threshold and the virtual vibration ratio is greater than a preset virtual vibration ratio reference, the illumination value is determined to be 1; otherwise, it is 0.

[0083] Step S105: The illumination intensity of each excitation source at each observation point is summed to obtain the total illumination intensity of each observation point.

[0084] When there is only one excitation source, this step is not required; the illumination intensity of the single excitation source is directly used as the total illumination intensity. When there is more than one excitation source, the illumination intensity of each observation point calculated for each excitation source is accumulated. By accumulating the illumination intensity of each excitation source, the total illumination intensity of the frequency domain electric source ground electromagnetic method with multiple excitation sources in multiple directions can be obtained.

[0085] Step S106: Determine the detectable area based on the total illumination and the preset illumination threshold.

[0086] An illumination threshold can be preset. The total illumination at each observation point is compared to this threshold. If it is greater than or equal to the threshold, the area is considered detectable; otherwise, it is considered undetectable. The illumination threshold can be set to 1 or other values ​​as needed. A higher total illumination indicates more sufficient illumination. The detection capability of a multi-source coverage area is evaluated based on the total illumination. When the threshold is set to 1, areas with illumination greater than or equal to 1 are considered detectable. A higher value indicates more sufficient illumination and better detection results. Detection depth can be estimated using the exploration depth formula.

[0087] In some optional embodiments, the above method further includes:

[0088] Step S107: Determine the detection depth of the detectable area based on the average resistivity and electromagnetic field frequency of the detection area.

[0089] In this step, the detection depth H of the detectable area can be determined using the following formula:

[0090]

[0091] Where H represents the exploration depth, which can be in meters (m) or other depth units; Rho is the average resistivity of the exploration area, which can be in ohm·m or other resistivity units that are compatible with the depth units; and f is the frequency of the electromagnetic field, which can be in Hz or other frequency units.

[0092] The above can be performed for each set transmission frequency. Figure 1 The method shown calculates the illumination at each observation point of the ground electromagnetic method for electric sources at different transmission frequencies.

[0093] The frequency-domain electrical source induction electromagnetic method detection capability evaluation method provided in this invention generates an electrical model of the exploration area based on its electrical structural characteristics. Then, using the electrical model, it performs forward modeling to obtain the vertical magnetic field components of each excitation source at each observation point, as well as the components to be evaluated. Based on the simulation results, it determines the virtual vibration ratio of the vertical magnetic field at each observation point, further determines the detection illumination based on the virtual vibration ratio, and determines the detectable area after excitation by the excitation source based on the detection illumination. This method can accurately determine the detection area after excitation by the excitation source and accurately evaluate the detection capability of the excitation source. It is applicable to the detection capability evaluation of multiple excitation sources in multiple directions, as well as the detection capability evaluation of a single excitation source, demonstrating strong applicability.

[0094] The method described in this embodiment of the invention enables the calculation of illumination by a multi-directional, multi-field source frequency-domain electric source ground electromagnetic method. This calculation method uses a preset geodetic model, excitation sources, and observation parameters to perform forward modeling, obtaining multiple electric and magnetic components, including a vertical magnetic component. The imaginary part of the vertical magnetic component represents the induced secondary field, while the amplitude represents the total field. In this method, the ratio of the imaginary component of the vertical magnetic field to the amplitude (imaginary vibration ratio) characterizes the proportion of the induced secondary field in the total field. The illumination of a single emission source is analyzed using the imaginary vibration ratio of the vertical magnetic field and the signal intensity obtained from the forward modeling. Finally, the illumination of the multi-directional, multi-field source frequency-domain electromagnetic method is obtained by summing the illumination of the observation area from each source excited in multiple directions.

[0095] The above method can calculate illumination for each excitation frequency, separately calculating the illumination at different excitation frequencies, and analyzing the detectable area size and detection depth at different excitation frequencies. When evaluation is required for multiple excitation frequencies, a specific implementation flow of the above method can be found in [link to implementation details]. Figure 2 As shown. It includes the following steps:

[0096] 1) Begin.

[0097] 2) Design the geoelectric model.

[0098] 3) Set the background noise of electric and magnetic field components, and the reference for the virtual vibration ratio of the vertical magnetic field, etc.

[0099] 4) Set the excitation parameters (or emission parameters) and observation parameters.

[0100] 5) Set the observation frequency.

[0101] 6) Forward modeling yields the observation components for each observation point.

[0102] 7) Calculate the virtual amplitude ratio of the vertical magnetic field at each measuring point.

[0103] 8) The illumination of each source at each observation point of each component is accumulated to obtain the illumination of each observation point under multi-source coverage.

[0104] 9) Determine if the illuminance calculation for all frequencies has been completed. If yes, proceed to step 10). If not, return to step 5.

[0105] 10) End.

[0106] For detailed implementation processes of the above steps, please refer to [link / reference]. Figure 1 The relevant description in the document.

[0107] The following describes specific embodiments for evaluating the detection capability of frequency-domain electrical sources using the above method. For the sake of simplicity, single-directional source 1, two-directional source 2, and four-directional source 4 under uniform half-space conditions are used as examples to illustrate the implementation effect of the present invention.

[0108] Assume the earth model is a uniform half-space of 100 ohm·m, the length of the source is 2km, the emission current is 10A, and the emission frequency is 10Hz. In the inversion region of 15km×15km centered on the source, observe the horizontal electric field of each source along the emission line method, that is, the Ex electric field of each source. This is also a component that is frequently observed in the current artificial source frequency domain induction electromagnetic method.

[0109] Let the background noise of the electric field be 1.e -7 V / m, calculate illumination according to the far-field observation mode, and set the virtual vibration ratio benchmark of the vertical magnetic field to 0.7.

[0110] Figure 3-5 This is an example of a simulation with a single source in one orientation. Wherein,

[0111] Figure 3 This is a schematic diagram showing the location of a single source in one orientation. Figure 4 This is a planar diagram of the Ex electric field amplitude after single-direction excitation by a single source. Figure 5 The illumination plan determined for a single-source illumination from one direction, from Figure 3-5 As can be seen, the amplitude of the Ex electric field of a single source is distributed in a four-petal flower shape on the plane, and decays rapidly from the source outwards. Under the conditions of far-field observation, the illumination also extends outwards in a four-petal flower shape to a certain distance. Due to the need to maintain a certain transmit-receive distance, it is not observable near the source.

[0112] Figure 6-9 This is an example of a simulation with two sources in both directions.

[0113] Figure 6 This is an example diagram showing the source locations of two bidirectional sources. Figure 7 This is a planar diagram of the electric field amplitude of Ex after the first source excitation. Figure 8 This is a planar diagram of the electric field amplitude of Ex after being excited by the second source. Figure 9 The illumination plane distribution diagram determined by the two sources in both directions. Figure 9The distribution of illumination is clearly shown. The center of the survey area is covered by two sources and has high illumination, making it a region with strong detection capabilities. The upper and lower ends are also observable areas, but only have single-source illumination.

[0114] Figure 10-15 This is an example of a simulation with four sources in four directions. Figure 10 This is an example diagram showing the source locations of four sources in four directions. Figure 11 This is a planar diagram of the electric field amplitude of Ex after the first source excitation. Figure 12 This is a planar diagram of the electric field amplitude of Ex after being excited by the second source. Figure 13 This is a planar diagram of the electric field amplitude of Ex after being excited by the third source. Figure 14 This is a planar diagram of the Ex electric field amplitude after the fourth source excitation. Figure 15 The illumination distribution plan is determined for four sources in four directions.

[0115] Figure 15 The illumination distribution map can be clearly displayed. The center of the survey area is a 4-source coverage area with the highest illumination and is the area with the strongest detection capability. The four corners are 2-source coverage areas with the second highest illumination. The surrounding area is a single-source coverage area. The vicinity of each source is also an unobservable area, but the range of unobservable areas near the source is smaller compared to the single-source condition.

[0116] Based on the same inventive concept, embodiments of the present invention also provide a device for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method, such as... Figure 16 As shown, it includes:

[0117] Model building module 11 is used to generate an electrical model of the exploration area based on the electrical structural characteristics of the exploration area.

[0118] The forward modeling module 12 is used to perform forward modeling based on preset emission parameters and observation parameters, using the electrical model to simulate the observation components of each excitation source at each observation point. The observation components include the vertical magnetic field component and the electric field and / or magnetic field component to be evaluated.

[0119] The illumination determination module 13 is used to determine the virtual ratio of the vertical magnetic field at each observation point for each excitation source, based on the vertical magnetic field component at each observation point. The virtual ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field. Based on the amplitude of the electric or magnetic field component to be evaluated at each observation point, the virtual ratio, the preset virtual ratio benchmark, and the preset background noise parameters, the detection illumination at each observation point is determined. The detection illumination of each excitation source at each observation point is accumulated to obtain the total illumination at each observation point.

[0120] The detection capability evaluation module 14 is used to determine the detectable area based on the total illumination and the preset illumination threshold.

[0121] In some alternative embodiments, the detection capability evaluation module 14 is further configured to: determine the detection depth of the detectable area based on the average resistivity of the detection area and the frequency of the electromagnetic field.

[0122] This invention also provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described frequency-domain electrical source induction electromagnetic detection capability evaluation method.

[0123] This invention also provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method.

[0124] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0125] Unless otherwise specifically stated, terms such as processing, calculation, operation, determination, display, etc., may refer to the actions and / or processes of one or more processing or computing systems or similar devices that represent the manipulation and conversion of data representing physical (e.g., electronic) quantities within the registers or memory of the processing system into other data similarly representing physical quantities within the memory, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0126] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0127] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0128] Those skilled in the art will also understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in alternative ways for each specific application; however, such implementation decisions should not be construed as departing from the scope of this disclosure.

[0129] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied in hardware, software modules executed by a processor, or a combination thereof. The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. The ASIC can reside in a user terminal. Alternatively, the processor and storage medium can exist as discrete components in the user terminal.

[0130] For software implementation, the techniques described in this application can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. This software code can be stored in memory units and executed by a processor. The memory units can be implemented within the processor or outside the processor; in the latter case, they are communicatively coupled to the processor via various means, as is well known in the art.

[0131] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A method for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method, characterized in that, include: Based on the electrical structural characteristics of the exploration area, an electrical model of the exploration area is generated; Based on the preset emission parameters and observation parameters, the electrical model is used to perform forward modeling to simulate the observation components of each excitation source at each observation point. The observation components include the vertical magnetic field component and the electric or magnetic field component to be evaluated. For each excitation source, the virtual vibration ratio of the vertical magnetic field at each observation point is determined based on the vertical magnetic field component at each observation point. The virtual vibration ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field. Based on the amplitude of the electric or magnetic field components to be evaluated at each observation point, the virtual ratio, the preset virtual ratio benchmark, and the preset background noise parameters, determine the detection illumination at each observation point. The total illumination at each observation point is obtained by summing the detection illumination of each excitation source at each observation point. The detectable area is determined based on the total illuminance and the preset illuminance threshold.

2. The method as described in claim 1, characterized in that, The generation of an electrical model of the exploration area based on its electrical structural characteristics includes: Based on the earth resistivity of the exploration area, an electrical model characterizing the earth resistivity distribution is generated; the electrical model is at least one of a three-dimensional model, a two-dimensional model, a uniform half-space model, and a layered half-space model.

3. The method as described in claim 1, characterized in that, The emission parameters include emission source parameters and emission source excitation parameters; the emission source parameters include emission source position and emission source length; the emission source excitation parameters include excitation current and emission frequency; The observation parameters include the receiver location and the observation components; the observation components include the vertical magnetic field component and the electric or magnetic field component to be evaluated.

4. The method as described in claim 1, characterized in that, Based on preset emission and observation parameters, the electrical model is used to perform forward modeling to simulate the observation components of each excitation source at each observation point, including: If the electrical model is a three-dimensional model, the observation components of each excitation source at each observation point are simulated using the three-dimensional forward modeling method; If the electrical model is a two-dimensional model, the observation components of each excitation source at each observation point are simulated using the two-dimensional forward modeling method. If the electrical model is a uniform half-space model or a layered half-space model, the observation components of each excitation source at each observation point are simulated using a one-dimensional forward modeling method.

5. The method as described in claim 1, characterized in that, The determination of the detection illumination at each observation point, based on the amplitude of the electric or magnetic field component to be evaluated, the virtual vibration ratio, the preset virtual vibration ratio benchmark, and the preset background noise parameters, includes: It determines whether the amplitude of the electric or magnetic field component to be evaluated at the observation point is greater than the preset background noise threshold, and whether the virtual vibration ratio of the observation point is greater than or equal to the preset virtual vibration ratio benchmark. If both are true, then the illumination of the observation point is determined to be the first specified value; otherwise, the illumination of the observation point is determined to be the second specified value.

6. The method as described in claim 1, characterized in that, A virtual vibration ratio benchmark is set for the exploration area; or different virtual vibration ratio benchmarks are set for observation areas at different distances in the exploration area according to the differences in the distance of the observation areas. The virtual vibration ratio reference value ranges from 0.15 to 0.7; where the value is 0.7 for far-field observations and 0.15 for near-field observations, and 0.15-0.7 is the value range for the transition zone.

7. The method as described in claim 1, characterized in that, Also includes: The detection depth of the detectable area is determined based on the average resistivity and electromagnetic field frequency of the detection area.

8. The method as described in claim 7, characterized in that, The detection depth H of the detectable area is determined using the following formula: Where Rho is the average resistivity of the exploration area, and f is the frequency of the electromagnetic field.

9. A device for evaluating the detection capability of frequency-domain electrical source induction electromagnetic method, characterized in that, include: The model building module is used to generate an electrical model of the exploration area based on its electrical structural characteristics. The forward modeling module is used to perform forward modeling of the observed components of each excitation source at each observation point based on preset emission parameters and observation parameters using the electrical model. The observed components include the vertical magnetic field component and the electric or magnetic field component to be evaluated. The illumination determination module is used to determine the virtual ratio of the vertical magnetic field at each observation point for each excitation source, based on the vertical magnetic field component at each observation point. The virtual ratio is the ratio of the imaginary part of the vertical magnetic field component to the amplitude of the vertical magnetic field. Based on the amplitude of the electric or magnetic field components to be evaluated at each observation point, the virtual ratio, the preset virtual ratio benchmark, and the preset background noise parameters, determine the detection illumination at each observation point. The total illumination at each observation point is obtained by summing the detection illumination of each excitation source at each observation point. The detection capability evaluation module is used to determine the detectable area based on the total illumination and the preset illumination threshold.

10. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when executed by a processor, implement the frequency-domain electrical source induction electromagnetic detection capability evaluation method according to any one of claims 1-8.

11. A computer device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the frequency-domain electrical source induction electromagnetic detection capability evaluation method according to any one of claims 1-8.

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