Universe apparent resistivity iteration initial value setting method, system, equipment and product

Abstract

The invention discloses a global apparent resistivity iteration initial value setting method and device, a medium and a product, and relates to the technical field of electromagnetic detection, and the method comprises the steps: selecting a plurality of roughly estimated resistivity values in a preset resistivity range according to logarithm equal intervals, and constructing a corresponding roughly estimated resistivity model according to the values; and then calculating the transient electromagnetic response of each roughly estimated model on different time channels, and comparing the transient electromagnetic response with the actually measured transient electromagnetic response to obtain a response deviation value of the model. Therefore, an initial resistivity initial value is selected. Then, transient electromagnetic response fitting is carried out on a plurality of time channels of the shallow layer, and a more accurate resistivity estimation value is obtained. Based on the finely-estimated resistivity values, the finely-estimated initial resistivity value of each time channel is further calculated. And finally, aiming at any time channel, fitting transient electromagnetic response of the time channel, and by taking the difference between the minimum actual measurement value and the predicted value as a target, determining a final resistivity initial value of the time channel.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic detection, and particularly to a method, device, medium and product for setting an initial value of iterative global apparent resistivity. Background Art

[0002] The Transient Electromagnetic Method (TEM) is a core branch of active-source time-domain electromagnetic detection technology. This method excites an eddy current field in the underground medium by transmitting a transient pulse current, and infers the electrical structure of the underground medium by observing the decay response of the secondary field. Based on the electromagnetic diffusion principle described by Maxwell's equations, and using the characteristic that electromagnetic field signals at different times correspond to different detection depths, TEM can achieve three-dimensional detection of underground electrical parameters. Its core advantages lie in the high-sensitivity response characteristics to low-resistivity bodies and the resolution ability of wide-time-window data for multi-scale geological targets. Currently, TEM has been widely applied in detection fields such as deep mineral exploration, geothermal resource evaluation, and geological disaster investigation and restoration. In transient electromagnetic detection, the apparent resistivity definition technique is usually used to convert the transient electromagnetic response into the apparent resistivity of the earth for intuitive analysis, so as to analyze the electrical distribution of the underground medium.

[0003] The apparent resistivity definition method has the advantages of simple calculation and unique results, and is one of the most basic and important transient electromagnetic data processing and interpretation techniques at present. Due to the complexity of the transient electromagnetic field, traditional apparent resistivity definitions need to distinguish between near and far zones or early and late periods, and there are problems that the transition period and the transition zone cannot be effectively defined. The global apparent resistivity definition of transient electromagnetic fields establishes a mapping relationship between the transient electromagnetic field response and the electrical properties of the underground medium through iterative techniques, which can effectively eliminate the influence of the field source geometric diffusion effect, and there is no need to define the apparent resistivity by dividing zones and periods, solving the problem of defining the apparent resistivity in the transition period and the transition zone. However, the current global apparent resistivity definition of transient electromagnetic fields faces significant non-uniqueness problems in practical applications. Especially when the initial value of the iterative resistivity is selected unreasonably, the iteration enters the wrong branch, resulting in apparent resistivity values that can fit the data but are significantly unreasonable, leading to jump points in the global apparent resistivity curve. This non-uniqueness is particularly prominent in laterally inhomogeneous geological bodies, and finally manifests as lateral discontinuity or pseudo-anomaly beaded distribution in the global apparent resistivity profile, seriously restricting the ability to finely depict geological structures such as faults and lithological boundaries. To solve this problem, it is necessary to make the initial value of the iterative apparent resistivity as close to the true value as possible. However, since the electrical characteristics of the underground medium are exactly the unknowns to be detected and interpreted, it is difficult to make an effective and accurate estimate. Summary of the Invention

[0004] The purpose of this application is to provide a method, device, medium, and product for setting the initial value of the global apparent resistivity iteration, which can improve the accuracy of setting the initial value of the iterative resistivity, thereby obtaining an accurate global apparent resistivity value.

[0005] To achieve the above objective, this application provides the following solutions: In a first aspect, this application provides a method for setting the initial value of the global apparent resistivity iteration, including the following steps: Select a number of roughly estimated resistivities at logarithmic equal intervals within a preset resistivity range, and construct a number of roughly estimated resistivity models.

[0006] For any one of the roughly estimated resistivity models, calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels, and compare it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the roughly estimated resistivity model.

[0007] Take the roughly estimated resistivity model with the lowest response deviation value as the primary selected initial resistivity value, fit the transient electromagnetic response of several time channels in the shallow layer, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the finely estimated resistivity value.

[0008] Based on the finely estimated resistivity value, calculate the initial value of the finely estimated resistivity for each time channel.

[0009] For any time channel, fit the transient electromagnetic response of the time channel, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel to obtain the final selected initial resistivity value of the time channel.

[0010] Optionally, selecting a number of roughly estimated resistivities at logarithmic equal intervals within a preset resistivity range and constructing a number of roughly estimated resistivity models specifically includes: Select a number of roughly estimated resistivities at logarithmic equal intervals within a preset resistivity range.

[0011] For any one of the roughly estimated resistivities, according to the transient electromagnetic theory, take a homogeneous half-space with a resistivity equal to the roughly estimated resistivity as the roughly estimated resistivity model corresponding to the roughly estimated resistivity.

[0012] Optionally, calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels according to the following formula: .

[0013] Among them, the superscript est represents the transient electromagnetic response of the roughly estimated resistivity model, is the transient electromagnetic response of the j th roughly estimated resistivity model at the i th time channel, Fis the transient electromagnetic response function, t i is the i th time channel, ρ j is the j th roughly estimated resistivity model.

[0014] The response deviation value of the roughly estimated resistivity model is calculated according to the following formula: .

[0015] Among them, is the response deviation value of the j th roughly estimated resistivity model, m is the number of time channels, d i is the measured transient electromagnetic response of the i th time channel.

[0016] Optionally, with the goal of minimizing the following formula, the finely estimated resistivity value is obtained: .

[0017] Among them, is the objective function value of the finely estimated resistivity value, l is the number of time channels in the shallow layer, l < m , d i is the i th measured transient electromagnetic response of the time channel, is the i th predicted transient electromagnetic response of the time channel.

[0018] Optionally, the initial value of the finely estimated resistivity of each time channel is calculated according to the following formula: .

[0019] Among them, ρ si is the initial value of the finely estimated resistivity of the i th time channel, ρ r is the finely estimated resistivity value, d i is the i th measured transient electromagnetic response of the time channel, F is the transient electromagnetic response function, t i is the i th time channel.

[0020] Optionally, with the goal of minimizing the following formula, the final selected initial resistivity value of the time channel is obtained: .

[0021] Among them, is the objective function value of the i th time channel, d i is the measured transient electromagnetic response of the i th time channel, is the predicted value of the transient electromagnetic response of the i th time channel.

[0022] Optionally, the Gauss-Newton method is used to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the refined resistivity value; the Gauss-Newton method is used to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel as the goal to obtain the initial value of the final selected resistivity of the time channel.

[0023] In a second aspect, the present application provides a system for setting the initial value of the global apparent resistivity iteration, including the following functional modules: A rough estimate resistivity model construction module for selecting a number of rough estimate resistivities at logarithmic equal intervals within a preset resistivity range and constructing a number of rough estimate resistivity models.

[0024] A response deviation value determination module for calculating the transient electromagnetic response of a rough estimate resistivity model at different time channels for any rough estimate resistivity model, and comparing it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the rough estimate resistivity model.

[0025] A refined estimate resistivity determination module for using the rough estimate resistivity model with the lowest response deviation value as the initial value of the preliminary selected resistivity, fitting the transient electromagnetic response of several time channels in the shallow layer, and taking the minimization of the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel as the goal to obtain the refined estimate resistivity value.

[0026] A refined estimate resistivity initial value determination module for calculating the initial value of the refined estimate resistivity of each time channel based on the refined estimate resistivity value.

[0027] A final selected resistivity initial value determination module for fitting the transient electromagnetic response of a time channel for any time channel, and taking the minimization of the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel as the goal to obtain the initial value of the final selected resistivity of the time channel.

[0028] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to implement the steps of the global apparent resistivity iteration initial value setting method described above.

[0029] Fourthly, the present application provides a computer program product, including a computer program which, when executed by a processor, implements the steps of the global apparent resistivity iterative initial value setting method described above.

[0030] According to the specific embodiments provided by the present application, the following technical effects are disclosed: The present application provides a global apparent resistivity iterative initial value setting method, device, medium and product. In this method, first, within a predetermined resistivity range, several roughly estimated resistivity values are selected at logarithmic equal intervals, and accordingly, a corresponding roughly estimated resistivity model is constructed. Then, for each roughly estimated resistivity model, its transient electromagnetic response on different time channels is calculated and compared with the actually measured transient electromagnetic response, so as to obtain the response deviation value of this model. Based on these deviation values, preliminary resistivity initial values are selected. Subsequently, the transient electromagnetic responses of several time channels in the shallow layer are fitted, with the goal of minimizing the difference between the actually measured value and the predicted value, so as to obtain more accurate resistivity estimation values. Based on these finely estimated resistivity values, the finely estimated resistivity initial value of each time channel is further calculated. Finally, for any time channel, by fitting its transient electromagnetic response and aiming at minimizing the difference between the actually measured value and the predicted value, the final resistivity initial value of this time channel is determined. The above solution of the present application first roughly estimates the initial value of the apparent resistivity based on the data of all time channels at a single measurement point. On this basis, multiple time channels are used to finely estimate the initial value of the apparent resistivity, and then the resistivity initial values of each time channel are calculated. Finally, the obtained resistivity initial values are used to define the global apparent resistivity, and accurate global apparent resistivity values on different time channels are obtained, eliminating problems such as non-smooth curves and jump points caused by unreasonable selection of the initial value in the traditional global apparent resistivity definition, and providing high-confidence global apparent resistivity data for transient electromagnetic data analysis and interpretation. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a schematic flowchart of a global apparent resistivity iterative initial value setting method provided by an embodiment of the present application.

[0033] Figure 2 It is a schematic diagram of a comparison curve between measured data and roughly estimated data in a global apparent resistivity iterative initial value setting method provided by an embodiment of the present application.

[0034] Figure 3Schematic diagram of the curve for finely estimating the initial resistivity value in a method for setting the initial value of the global apparent resistivity iteration provided by an embodiment of the present application.

[0035] Figure 4 Schematic diagram of the curve of the global apparent resistivity in a method for setting the initial value of the global apparent resistivity iteration provided by an embodiment of the present application.

[0036] Figure 5 Schematic diagram of the comparison curve of the global apparent resistivity obtained by respectively adopting the traditional setting method and the setting method provided by the present application.

[0037] Figure 6 Schematic diagram of the functional modules of a system for setting the initial value of the global apparent resistivity iteration provided by an embodiment of the present application.

[0038] Figure 7 Schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0040] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0041] A method for setting the initial value of the global apparent resistivity iteration provided by an embodiment of the present application, as Figure 1 shown, includes the following steps: A1. Select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range, and construct a number of roughly estimated resistivity models. In this embodiment, step A1 specifically includes: A11. Select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range.

[0042] A12. For any one of the roughly estimated resistivity values, according to the transient electromagnetic theory, take a homogeneous half-space with the resistivity being the roughly estimated resistivity value as the corresponding roughly estimated resistivity model.

[0043] A2. For any roughly estimated resistivity model, calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels, and compare it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the roughly estimated resistivity model. Calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels according to the following formula: .

[0044] Among them, the superscript est represents the transient electromagnetic response of the roughly estimated resistivity model, is the transient electromagnetic response of the j th roughly estimated resistivity model at the i th time channel, F is the transient electromagnetic response function, t i is the i th time channel, ρ j is the j th roughly estimated resistivity model.

[0045] Calculate the response deviation value of the roughly estimated resistivity model according to the following formula: .

[0046] Among them, is the response deviation value of the j th roughly estimated resistivity model, m is the number of time channels, d i is the measured transient electromagnetic response of the i th time channel.

[0047] A3. Take the roughly estimated resistivity model with the lowest response deviation value as the initial value of the preliminary selected resistivity, and fit the transient electromagnetic response of several time channels in the shallow layer. With the goal of minimizing the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel, obtain the refined estimated resistivity value. In this embodiment, the Gauss-Newton method is used to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the refined estimated resistivity value; specifically, with the goal of minimizing the following formula: .

[0048] Among them, is the objective function value of the refined estimated resistivity value, l is the number of time channels in the shallow layer, l < m , d i is the measured transient electromagnetic response of the i th time channel, is the iPredicted values of transient electromagnetic responses for each time channel.

[0049] A4. Based on the estimated resistivity values, the initial estimated resistivity values for each time channel are calculated. In this embodiment, the initial estimated resistivity values for each time channel are calculated according to the following formula: .

[0050] Where, ρ si is the initial estimated resistivity value for the i th time channel, ρ r is the estimated resistivity value, d i is the measured transient electromagnetic response for the i th time channel, F is the transient electromagnetic response function, t i is the i th time channel.

[0051] A5. For any time channel, the transient electromagnetic response of the time channel is fitted. With the goal of minimizing the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel, the final selected initial resistivity value of the time channel is obtained. In this embodiment, the Gauss-Newton method is used to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel as the goal to obtain the final selected initial resistivity value of the time channel; specifically, with the goal of minimizing the following formula: .

[0052] Where, is the objective function value for the i th time channel, d i is the measured transient electromagnetic response for the i th time channel, is the i th predicted value of the transient electromagnetic response of the time channel.

[0053] The present invention will be further described in detail below with a specific embodiment.

[0054] First, prepare the measured transient electromagnetic responses at the position (-10m, 150m) of the three-layer earth model D = d 1, d 2,..., d i ,..., d 31 , and the parameters of the three-layer earth model are shown in Table 1. The measured transient electromagnetic responses are as shown in the measured data in Figure 2 , with a total of 31 time channels.d i To correspond to the i th time channel t i of the transient electromagnetic response value.

[0055] Table 1 Parameters of the three-layer earth model

[0056] B1. Construct a sequence of roughly estimated resistivity values in the range of 0.1~100000 Ω·m at logarithmic equal intervals ρ 1, ρ 2, …, ρ j , …, ρ 60 , the sequence contains a total of 60 roughly estimated resistivity values. According to the transient electromagnetic theory, take the resistivity of the j th roughly estimated resistivity ρ j of the homogeneous half-space as the j th roughly estimated resistivity model to obtain 60 roughly estimated resistivity models.

[0057] B2. Adopt the analytical solution of the transient electromagnetic response of an electric dipole and the dipole superposition method to calculate the responses of the j th roughly estimated resistivity model at different time channels: .

[0058] Among them, the superscript est represents the transient electromagnetic response of the roughly estimated resistivity model, is the transient electromagnetic response of the j th roughly estimated resistivity model at the i th time channel, F is the transient electromagnetic response function, t i is the i th time channel, ρ j is the j th roughly estimated resistivity model.

[0059] For the transient electromagnetic responses of all time channels, compare them with the measured transient electromagnetic responses of the corresponding time channels, and calculate the response deviation values of the roughly estimated resistivity models according to the following formula: .

[0060] Among them, is the response deviation value of the j th roughly estimated resistivity model, m is the number of time channels, di is the measured transient electromagnetic response of the i th time channel.

[0061] B3. The response deviation values calculated in step B2 form a response deviation sequence δ 1, δ 2, …, δ j , …, δ 60 . Select the serial number of the roughly estimated resistivity model with the smallest response deviation value in the response deviation sequence k = 29, the corresponding roughly estimated resistivity value is 85.76 Ω·m, the corresponding deviation value is 18.69%, and the roughly estimated response is as Figure 2 shown in the roughly estimated data in ρ 29 . Select the roughly estimated resistivity model as the initial value of the initially selected resistivity, adjust the resistivity value, and fit the transient electromagnetic data of the first 3 time channels. Use the following objective function:

[0062] where, is the objective function value of the finely estimated resistivity value, l is the number of time channels in the shallow layer, l < m , d i is the measured transient electromagnetic response of the i th time channel, is the i th time channel's predicted transient electromagnetic response value. In this embodiment, the Gauss-Newton method is used to minimize the above objective function to obtain the finely estimated resistivity value ρ r = 92.73 Ω·m.

[0063] B4. Based on the finely estimated resistivity value, calculate the initial value of the finely estimated resistivity for each time channel. In this embodiment, the initial value of the finely estimated resistivity for each time channel is calculated according to the following formula: .

[0064] where, ρ si is the initial value of the finely estimated resistivity of the i th time channel, ρ r is the finely estimated resistivity value, d i is the i th time channel's measured transient electromagnetic response, F is the transient electromagnetic response function, t i is thei a time channel. A detailed evaluation of the initial resistivity value curve is as Figure 3 shown.

[0065] B5. For any time channel, the transient electromagnetic response of the time channel is successively fitted, aiming to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel, and the final selected initial resistivity value of the time channel is obtained. Specifically, aiming to minimize the following formula: .

[0066] Wherein, is the objective function value of the i th time channel, d i is the measured transient electromagnetic response of the i th time channel, is the predicted value of the transient electromagnetic response of the i th time channel.

[0067] In this embodiment, the Gauss-Newton method is used to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel, and the final selected initial resistivity value of the time channel is obtained. The finally obtained global apparent resistivity curve is as Figure 4 shown, which more completely and accurately reflects the resistivity values in the shallow part of the earth and the deep electrical change law. Figure 5 shows the global apparent resistivity curve obtained by using the traditional global apparent resistivity iteration initial value setting method and its comparison with the result obtained in this application. It can be seen that generally speaking, the two are relatively close, but the result curve of the traditional method has poor smoothness and there are some jump points, while the global apparent resistivity curve calculated by using the initial value setting method of this application is more continuous and accurate, avoiding the jump point problem in the traditional method and being able to effectively reflect the earth's electrical change law.

[0068] By optimizing the global apparent resistivity definition iteration initial value setting method, this application can effectively obtain the estimated values of the apparent resistivity of different time channels, make the iteration initial value close to the true value, ensure the accuracy of the iteration direction, and obtain the correct global apparent resistivity value; the solution proposed in this application can effectively solve the problems of jump points and non-smoothness of the global apparent resistivity curve caused by unreasonable setting of the iteration initial value, improve the reliability of the global apparent resistivity definition, and provide a global apparent resistivity value with high credibility for subsequent analysis and interpretation.

[0069] Based on the same inventive concept, the embodiment of this application also provides a system for implementing a global apparent resistivity iteration initial value setting method involved above. The solution provided by this system to solve the problem is similar to the solution recorded in the above method. In an exemplary embodiment, as Figure 6As shown, a system for setting the initial value of the global apparent resistivity by iteration is provided, including the following functional modules: A rough estimation resistivity model construction module is used to select a number of rough estimation resistivities at logarithmic equal intervals within a preset resistivity range and construct a number of rough estimation resistivity models.

[0070] A response deviation value determination module is used to calculate the transient electromagnetic response of a rough estimation resistivity model at different time channels for any rough estimation resistivity model, and compare it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the rough estimation resistivity model.

[0071] A fine estimation resistivity determination module is used to take the rough estimation resistivity model with the lowest response deviation value as the initial value of the primary selected resistivity, fit the transient electromagnetic response of several time channels in the shallow layer, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the fine estimation resistivity value.

[0072] A fine estimation resistivity initial value determination module is used to calculate the initial value of the fine estimation resistivity for each time channel based on the fine estimation resistivity value.

[0073] A final selected resistivity initial value determination module is used to fit the transient electromagnetic response of a time channel for any time channel, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel to obtain the final selected resistivity initial value of the time channel.

[0074] The above solution provided by the present application roughly estimates the initial value of the apparent resistivity based on all time channel data of a single measurement point. On this basis, multiple time channels are used to finely estimate the initial value of the apparent resistivity, and then the initial value of the resistivity of each time channel is calculated. Finally, the obtained initial value of the resistivity is used to define the global apparent resistivity, and accurate global apparent resistivity values on different time channels are obtained, eliminating problems such as non-smooth curves and jump points caused by unreasonable selection of the initial value in the traditional definition of the global apparent resistivity, and providing high-confidence global apparent resistivity data for the analysis and interpretation of transient electromagnetic data.

[0075] Of course, Figure 6 The architecture shown is only exemplary. When implementing different functions, one or at least two components in the system shown can be omitted according to actual needs. Figure 6 shown in the system.

[0076] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 7As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it can implement a method for setting an initial value of global apparent resistivity iteration provided in the foregoing embodiments.

[0077] Those skilled in the art can understand that Figure 7 the structure shown in the figure is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0078] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the foregoing method embodiments are implemented.

[0079] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by the processor, the steps in the foregoing method embodiments are implemented.

[0080] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by the processor, the steps in the foregoing method embodiments are implemented.

[0081] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0082] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0083] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0084] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0085] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for setting an initial value of global apparent resistivity iteration, characterized in that, Including: Select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range, and construct a number of roughly estimated resistivity models; For any one of the roughly estimated resistivity models, calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels, and compare it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the roughly estimated resistivity model; Take the roughly estimated resistivity model with the lowest response deviation value as the initial value of the preliminary selected resistivity, fit the transient electromagnetic response of several time channels in the shallow layer, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the finely estimated resistivity value; Based on the finely estimated resistivity value, calculate the initial value of the finely estimated resistivity for each time channel; For any time channel, fit the transient electromagnetic response of the time channel, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel to obtain the final selected initial resistivity value of the time channel.

2. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein, Select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range, and construct a number of roughly estimated resistivity models, specifically including: Select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range; For any one of the roughly estimated resistivity values, according to the transient electromagnetic theory, take a homogeneous half-space with the resistivity being the roughly estimated resistivity as the roughly estimated resistivity model of the corresponding roughly estimated resistivity.

3. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein, Calculate the transient electromagnetic response of the roughly estimated resistivity model at different time channels according to the following formula: ； Among them, the superscript est represents the transient electromagnetic response of the roughly estimated resistivity model, is the transient electromagnetic response of the j th roughly estimated resistivity model at the i th time channel, F is the transient electromagnetic response function, t i is the i th time channel, ρ j is the j th roughly estimated resistivity model; Calculate the response deviation value of the roughly estimated resistivity model according to the following formula: ； Among them, is the response deviation value of the j th rough estimated resistivity model, m is the number of time channels, d i is the measured transient electromagnetic response of the i th time channel.

4. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein Aim to minimize the following formula to obtain the finely estimated resistivity value: ； Among them, is the objective function value for estimating the resistivity value in detail, l is the number of time channels in the shallow layer, l < m , d i is the measured transient electromagnetic response of the i th time channel, is the predicted value of the transient electromagnetic response of the i th time channel.

5. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein Calculate the initial value of the finely estimated resistivity for each time channel according to the following formula: ； Among them, ρ si is the initial value of the refined estimated resistivity for the i th time channel, ρ r is the refined estimated resistivity value, d i is the measured transient electromagnetic response for the i th time channel, F is the transient electromagnetic response function, t i is the i th time channel.

6. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein, Aim to minimize the following formula to obtain the final selected initial resistivity value of the time channel: ； Among them, is the objective function value of the i th time channel, d i is the measured transient electromagnetic response of the i th time channel, is the predicted value of the transient electromagnetic response of the i th time channel.

7. The method for setting the initial value of the global apparent resistivity iteration according to claim 1, wherein Use the Gauss-Newton method to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the finely estimated resistivity value; use the Gauss-Newton method to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel as the goal to obtain the final selected initial resistivity value of the time channel.

8. An initial value setting system for global apparent resistivity iteration, characterized in that, Including: A roughly estimated resistivity model construction module, which is used to select a number of roughly estimated resistivity values at logarithmic equal intervals within a preset resistivity range and construct a number of roughly estimated resistivity models; A response deviation value determination module, which is used to calculate the transient electromagnetic response of any one of the roughly estimated resistivity models at different time channels and compare it with the measured transient electromagnetic response of the corresponding time channel to obtain the response deviation value of the roughly estimated resistivity model; A finely estimated resistivity determination module, which is used to take the roughly estimated resistivity model with the lowest response deviation value as the initial value of the preliminary selected resistivity, fit the transient electromagnetic response of several time channels in the shallow layer, and aim to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the corresponding time channel to obtain the finely estimated resistivity value; A finely estimated resistivity initial value determination module, which is used to calculate the initial value of the finely estimated resistivity for each time channel based on the finely estimated resistivity value; The final selection resistivity initial value determination module is used to fit the transient electromagnetic response of any time channel, aiming to minimize the difference between the measured transient electromagnetic response and the predicted value of the transient electromagnetic response of the time channel, so as to obtain the final selection resistivity initial value of the time channel.

9. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the global apparent resistivity iterative initial value setting method according to any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the global apparent resistivity iterative initial value setting method according to any one of claims 1-7.

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