A method for inverting borehole transient electromagnetic pseudo-3D data from multi-point joint detection

Abstract

This invention relates to the field of geophysical exploration technology, and particularly to a method, apparatus, electronic device, and computer-readable storage medium for inverting borehole transient electromagnetic pseudo-3D data from multi-point joint detection. The method includes: emitting a pulsed magnetic field at the borehole opening to acquire an observation dataset; constructing an initial inversion model and pre-setting values ​​for model parameters; based on the equivalent eddy current principle, constructing a functional relationship between the model parameters and the forward modeling theoretical data to obtain the inversion objective function; using a simulated annealing algorithm, with the initial inversion model as the initial iteration condition, iteratively optimizing the inversion objective function to obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstructing the model parameters based on the electrical parameters. Introducing the equivalent eddy current principle and the simulated annealing algorithm into the transient electromagnetic forward modeling calculation of the entire mine space ensures the accuracy and practicality of the final inversion results.

Description

Technical Field

[0001] This application relates to the field of geophysical exploration technology, and in particular to a method, apparatus, electronic device, and computer-readable storage medium for inverting borehole transient electromagnetic pseudo-3D data from multi-point joint exploration. Background Technology

[0002] Transient electromagnetic methods (TEM) invert the electrical structure of the subsurface by transmitting transient electromagnetic pulses on the surface or underground and observing the secondary electromagnetic fields induced in the subsurface medium. This method is widely used in mineral exploration, groundwater detection, environmental surveys, and geological hazard assessment. Borehole TEM, as a special form of TEM, places the receiving probe inside the borehole, enabling close-range, high-resolution detection of the surrounding geological bodies, and is particularly suitable for identifying deep geological structures and water-bearing anomalies.

[0003] However, the inversion of transient electromagnetic data from boreholes still faces many challenges. Traditional inversion methods are often heavily reliant on the initial model, easily getting trapped in local extrema, leading to unstable or distorted inversion results. Furthermore, the electromagnetic field response under full-space conditions is complex, making direct 3D inversion computationally intensive and inefficient. Although global optimization algorithms such as Bayesian inversion, genetic algorithms, and particle swarm optimization have been introduced to improve inversion results, efficient and robust inversion methods are still lacking in the real-world environment of mines with full space, multiple measurement points, and strong interference. In particular, there is currently no multi-point joint constraint inversion method for transient electromagnetic data from mine boreholes. Most methods are still based on single-point inversion, making it difficult to fully utilize the complementary and constraint relationships between multiple measurement points in space, resulting in insufficient accuracy in locating and identifying water-bearing anomalies. In addition, conventional inversion methods often employ complex numerical methods such as multiple integrations when calculating the transient electromagnetic response across the entire space, resulting in a heavy computational burden and failing to meet the dual requirements of efficiency and accuracy in practical exploration.

[0004] Therefore, developing a borehole transient electromagnetic pseudo-3D inversion method that is applicable to all space conditions in mines, can comprehensively utilize data from multiple measurement points, has global optimization capabilities, and has high computational efficiency has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] This application aims to at least partially address one of the technical problems in the related art.

[0006] Therefore, the first objective of this application is to propose a method for inverting borehole transient electromagnetic pseudo-3D data through multi-point joint detection, in order to solve the problems that existing technologies lack efficient and robust inversion methods and cannot meet the dual requirements of efficiency and accuracy in actual exploration.

[0007] The second objective of this application is to provide an apparatus.

[0008] The third objective of this application is to propose an electronic device.

[0009] The fourth objective of this application is to provide a computer-readable storage medium.

[0010] To achieve the above objectives, the first aspect of this application proposes a method for inverting borehole transient electromagnetic pseudo-3D data through multi-point joint detection, comprising:

[0011] A pulsed magnetic field is emitted at the borehole opening to obtain an observation dataset.

[0012] Construct an initial inversion model and preset the values ​​of the model parameters;

[0013] Based on the equivalent eddy current principle, a functional relationship between the model parameters and the forward modeling theoretical data is constructed to obtain the inversion objective function. The construction of this functional relationship includes:

[0014] Calculate the transient electromagnetic response of the background field in the entire space;

[0015] The induced eddy current generated by the abnormal body after the current is turned off is equivalent to a current loop, and the abnormal field response generated by the current loop is calculated using the Biot-Savart law.

[0016] The transient electromagnetic response is superimposed on the abnormal field response to obtain the total field response, which is used as forward modeling data.

[0017] The simulated annealing algorithm is used to iteratively optimize the inversion objective function with the inversion initial model as the initial condition for iteration, obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstruct the model parameters based on the electrical parameters.

[0018] Preferably, the step of emitting a pulsed magnetic field at the borehole opening to obtain the observation dataset includes:

[0019] A pulsed magnetic field is emitted at the borehole opening, and multiple measuring points are set up inside the borehole to measure the secondary magnetic field induced by the underground conductive geological body. The secondary magnetic field data from multiple measuring points are used as the observation dataset.

[0020] Preferably, the background field calculation formula is:

[0021]

[0022] in, , , for x , y , z The unit vector of direction. To emit magnetic moments, , magnetic permeability Electrical conductivity For time, The distance from the observation point to the source point;

[0023] The formula for calculating the abnormal field is:

[0024]

[0025] in, For equivalent current, For the current loop infinitesimal vector, The vector from the center of the sphere to the observation point. This is the distance from the center of the sphere to the observation point.

[0026] Preferably, the step of using simulated annealing algorithm, with the initial inversion model as the initial condition for iteration, to iteratively optimize the inversion objective function includes:

[0027] Set initial control parameters and randomly generate initial model parameters;

[0028] Perform forward modeling and evaluate the fitness of the current model parameters. If the fitness meets the accuracy requirements, terminate the iteration and output the results.

[0029] If the fitness does not meet the accuracy requirements, the current model parameters are randomly perturbed to generate a new model, and the fitness of the new model is calculated.

[0030] Determine whether the fitness of the new model meets the standard, gradually reduce the control parameters, and repeat the iterative calculation until the termination condition is met.

[0031] Preferably, the control parameters are updated according to an exponential decay law, and the calculation formula is as follows:

[0032]

[0033] in, The cooling coefficient is between 0 and 1. For the number of iterations, For the first Control parameters for the next iteration For the first Control parameters for the next iteration.

[0034] Preferably, the model parameters include the resistivity of the background medium, the resistivity of the anomalous body, the diameter of the anomalous body, and the three-dimensional spatial coordinates of the center of the anomalous body.

[0035] To achieve the above objectives, a second aspect of this application provides a borehole transient electromagnetic pseudo-3D data inversion device based on multi-point joint detection, comprising:

[0036] The data acquisition module emits a pulsed magnetic field at the borehole opening to acquire the observation dataset;

[0037] The model building module constructs the initial inversion model and presets the values ​​of the model parameters.

[0038] The function calculation module, based on the equivalent eddy current principle, constructs the functional relationship between the model parameters and the forward modeling theoretical data to obtain the inversion objective function. The construction of the functional relationship between the model parameters and the forward modeling theoretical data includes:

[0039] Calculate the transient electromagnetic response of the background field in the entire space;

[0040] The induced eddy current generated by the abnormal body after the current is turned off is equivalent to a current loop, and the abnormal field response generated by the current loop is calculated using the Biot-Savart law.

[0041] The transient electromagnetic response is superimposed on the abnormal field response to obtain the total field response, which is used as forward modeling data.

[0042] The iterative module employs a simulated annealing algorithm, using the initial inversion model as the initial condition for iteration, to iteratively optimize the inversion objective function, obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstruct the model parameters based on the electrical parameters.

[0043] To achieve the above objectives, a third aspect of this application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0044] The memory stores computer-executed instructions;

[0045] The processor executes computer execution instructions stored in the memory to implement the method described in any of the preceding descriptions.

[0046] To achieve the above objectives, a fourth aspect of this application provides a computer-readable storage medium, comprising computer-executable instructions stored therein, which, when executed by a processor, are used to implement the method described in any of the above embodiments.

[0047] This application provides a method for inverting borehole transient electromagnetic pseudo-3D data from multi-point joint detection, introducing the equivalent eddy current principle into the forward modeling calculation of transient electromagnetic data throughout the mine space. By equating the induced secondary field generated by complex anomalies to the magnetic field of a current loop and performing a one-time integration calculation using the Biot-Savart law, it cleverly avoids the multiple and complex integration processes required by traditional 3D numerical simulations, greatly simplifying the forward modeling calculation. While ensuring physical accuracy, it significantly reduces the time cost of a single forward modeling calculation. By using a large number of measurement points from different locations and angles within the borehole to jointly constrain the same geological model, it effectively suppresses the solution deviation caused by jumps or noise interference from individual measurement point data. Employing the simulated annealing algorithm, it has significant advantages over traditional gradient-based inversion methods when facing complex nonlinear geophysical inversion problems. It is less prone to failure due to improper initial model selection, has strong adaptability, and ensures the accuracy and practicality of the final inversion results.

[0048] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0049] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0050] Figure 1 A flowchart of a first specific embodiment of a multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion method provided by the present invention;

[0051] Figure 2 This is a flowchart of the inversion process;

[0052] Figure 3 A flowchart of a second specific embodiment of a multi-point joint detection borehole transient electromagnetic pseudo-three-dimensional data inversion method provided by the present invention;

[0053] Figure 4 A schematic diagram of a geological model for multi-point joint detection of low-resistivity anomalies using borehole transient electromagnetic methods;

[0054] Figure 5 The diagram shows a structural block diagram of a borehole transient electromagnetic pseudo-3D data inversion device for multi-point joint detection, provided in an embodiment of the present invention. Detailed Implementation

[0055] The core of this invention is to provide a method, device, electronic device, and computer-readable storage medium for inverting borehole transient electromagnetic pseudo-3D data through multi-point joint detection. It introduces the equivalent eddy current principle and simulated annealing algorithm into the transient electromagnetic forward modeling calculation of the entire mine space, ensuring the accuracy and practicality of the final inversion results.

[0056] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Please refer to Figure 1 , Figure 1 The flowchart illustrates a first specific embodiment of a multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion method provided by the present invention; the specific operation steps are as follows:

[0058] Step S101: Emits a pulsed magnetic field at the borehole opening to acquire the observation dataset;

[0059] Step S102: Construct the initial inversion model and preset the values ​​of the model parameters;

[0060] Step S103: Based on the equivalent eddy current principle, construct the functional relationship between the model parameters and the forward modeling theoretical data to obtain the inversion objective function;

[0061] Step S104: Using the simulated annealing algorithm, with the inversion initial model as the initial condition for iteration, the inversion objective function is iteratively optimized to obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and the model parameters are reconstructed based on the electrical parameters.

[0062] Based on the above embodiments, this embodiment will provide a detailed description of step S101:

[0063] In one embodiment, a primary pulse magnetic field is emitted at the borehole opening, and multiple measuring points are arranged inside the borehole to measure the secondary magnetic field induced by the underground conductive geological body. The secondary magnetic field data from the multiple measuring points are used as an observation dataset.

[0064] Based on the above embodiments, this embodiment will provide a detailed description of step S103:

[0065] In one embodiment, the transient electromagnetic response of the background field in the entire space is calculated;

[0066] The induced eddy current generated by the abnormal body after the current is turned off is equivalent to a current loop, and the abnormal field response generated by the current loop is calculated using the Biot-Savart law.

[0067] The transient electromagnetic response is superimposed on the abnormal field response to obtain the total field response, which is used as forward modeling data.

[0068] Specifically, under the excitation of an applied current field, induced eddy currents are generated in a conductor. After entering the late stage, the distribution of the induced eddy currents in the conductor tends to stabilize and decays exponentially. It can be equivalently represented by a current loop containing an inductance L and a resistance R. The current loop has a similar law to the external field of the late-stage induced eddy currents, and is called the "equivalent eddy current".

[0069] The calculation process of the transient electromagnetic response of a sphere under full-space conditions is as follows: first, the response of the background field in the whole space is calculated; then, the response of the secondary field (abnormal field) induced by the abnormal sphere is calculated by using the equivalent eddy current principle and the Biot-Savart law; finally, the background field and the abnormal field are superimposed to obtain the calculation result of the total field.

[0070] Background field calculation: Assuming a uniform model throughout space, the excitation source is located in... The current is constant at I during the time period. If the current is turned off at a certain moment, the magnetic field at a distance r from the source point after the turn-off can be expressed by the following formula:

[0071]

[0072] In the formula , , Let be the unit vectors in the x, y, and z directions, and m be the emitted magnetic moment (the magnitude of which is the equivalent area of ​​the coil multiplied by the current). ,in magnetic permeability Electrical conductivity, t is time, and r is the distance from the observation point to the source point.

[0073] Abnormal field calculation: After the current is turned off, the magnetic field induced by a water-containing sphere with diameter d in the field can be calculated using the current... The magnetic field generated by a square ring current with side length *a* is equivalently represented as follows: The magnetic field it generates is

[0074]

[0075] In the formula, The equivalent current is expressed as follows: , The decay time constant, , For electrical conductivity, , The initial equivalent current, , ,in, This indicates that at the center of the anomalous body (sphere), there is an emission current. The component of the generated magnetic field strength in a specific direction, Let be the distance from the source point to the center of the ball. Let be the vector from the source point to the center of the sphere. For the current loop infinitesimal vector, The vector from the center of the sphere to the observation point. This is the distance from the center of the sphere to the observation point.

[0076] Here, we cleverly utilize the concept of equivalent current to calculate the secondary field response directly using the Biot-Savart law with only one integration, thus avoiding the complex calculation process of multiple integrations required for directly calculating the secondary field response.

[0077] Total field calculation:

[0078]

[0079]

[0080] in, The rate of change of the total magnetic field with time; This is the total electromotive force induced in the receiving coil;

[0081] This represents the effective area of ​​the receiving coil.

[0082] Based on the above embodiments, this embodiment will provide a detailed description of step S104:

[0083] In one embodiment, initial control parameters are set, and initial model parameters are randomly generated; forward modeling is performed and the fitness of the current model parameters is evaluated. If the fitness meets the accuracy requirements, the iteration is terminated and the result is output; if the fitness does not meet the accuracy requirements, the current model parameters are randomly perturbed to generate a new model, and the fitness of the new model is calculated; it is determined whether the fitness of the new model meets the standard, the control parameters are gradually reduced, and the iterative calculation is repeated until the termination condition is met.

[0084] The control parameters are updated according to an exponential decay law, and the calculation formula is as follows:

[0085]

[0086] in, The cooling coefficient is between 0 and 1. For the number of iterations, For the first The control parameter (temperature) for the next iteration. For the first The control parameter (temperature) for the next iteration.

[0087] Specifically, such as Figure 2 As shown, transient electromagnetic nonlinear inversion under full-space conditions was performed based on the simulated annealing method.

[0088] 1. First, set the initial control parameter T0, and then randomly generate the initial model parameters. And perform full-space equivalent eddy forward modeling to calculate and fitness .

[0089] 2. If the fitness is within the control precision range, terminate the iteration and output the result;

[0090] 3. If the fitness does not meet the requirements, the model parameters are randomly modified to obtain... Re-perform forward modeling. And obtain fitness .

[0091] 4. Order ,like If yes, then accept the update; otherwise, calculate the probability density: Determine whether ρ(ΔE)>rand (rand is a random number between 0 and 1) is true. If it is true, update the parameters; otherwise, refuse to update the parameters.

[0092] 5. If the parameter modification is accepted, return to step 2 and output the result; otherwise, return to step 3 and perform the next iteration. Repeat this process until the fitness requirement is met, and finally output the result.

[0093] in, For the first The set of model parameters at the next iteration For the first The set of model parameters at +1 iteration; This is the set of theoretical response data for all measurement points obtained through forward modeling using the current model parameters; For the first Forward modeling data for each measurement point; For the first Actual observation data of each measuring point; This represents the total number of observation points; For the first The fitness of the model parameters (i.e., the objective function value) at each iteration is used to measure the difference in fit between the theoretical data and the observed data. For the first The fitness of the model parameters during the next iteration.

[0094] Regarding the selection of the control parameter T, based on previous research, an exponential variation pattern is more suitable for the essence of annealing, that is... .

[0095] This embodiment provides a method for inverting borehole transient electromagnetic pseudo-3D data using multi-point joint detection, introducing the equivalent eddy current principle into the forward modeling calculation of transient electromagnetic data throughout the mine space. By equating the induced secondary field generated by complex anomalies to the magnetic field of a current loop and performing a one-time integration calculation using the Biot-Savart law, it cleverly avoids the multiple and complex integration processes required by traditional 3D numerical simulations, greatly simplifying the forward modeling calculation model. While ensuring physical accuracy, it significantly reduces the time cost of a single forward modeling calculation. By using a large number of measurement points from different locations and angles within the borehole to jointly constrain the same geological model, it effectively suppresses the solution deviation caused by jumps or noise interference from individual measurement point data. Employing the simulated annealing algorithm, it has significant advantages over traditional gradient-based inversion methods when facing complex nonlinear geophysical inversion problems. It is less prone to failure due to improper initial model selection, has strong adaptability, and ensures the accuracy and practicality of the final inversion results.

[0096] Based on the above embodiments, this embodiment describes a method for inverting borehole transient electromagnetic pseudo-3D data using multi-point joint detection, as follows: Figure 3 As shown, the details are as follows:

[0097] This embodiment uses the example of detecting a hidden water-bearing anomaly next to a borehole in a mining area to illustrate the implementation process of the present invention.

[0098] 1. Geological modeling and data acquisition;

[0099] like Figure 4 As shown, a simulated full-space geological model of a mine is constructed. The background medium is homogeneous surrounding rock with a resistivity of 500 Ω·m. At a certain distance from the borehole, a low-resistivity water-bearing spherical anomaly is set with its center spatial coordinates at (50, 0, -60) meters, a diameter of 40 meters, and a resistivity of 1 Ω·m.

[0100] The implementation steps are as follows:

[0101] Transmission: A transmitting coil is positioned at the ground location (coordinates 0,0,0) at the borehole opening to transmit a single pulsed magnetic field. The transmitting current is a stable DC current, and at time [time missing]... Turn off.

[0102] Reception: Multiple receiving points are arranged within the borehole. In this embodiment, two sets of receiving point sequences are examined in detail: one set is located in a vertical borehole (100, 0, 0) beside the borehole opening, and the other set is located in a vertical borehole (0, 0, 0) directly below the transmitting point. The receiving points are distributed at certain intervals from the surface to a depth of 120 meters underground, and transient electromagnetic secondary field induced electromotive force data from a total of 14 receiving points are acquired as the observation dataset. .

[0103] 2. Inversion Implementation Process

[0104] Build the initial model and set parameters;

[0105] Construct an initial inversion model, with model parameters including background resistivity. The coordinates of the center of the anomalous sphere (x, y, z) and the diameter of the anomalous sphere. Abnormal spherical resistivity To simulate the uncertainty of the initial model in practical applications, broad upper and lower limits are set for these parameters. For example, the lower and upper limits of the background resistivity are set to 100 Ω·m and 1000 Ω·m, respectively, and the range of anomalous resistivity is set to 0.1 to 10 Ω·m.

[0106] Forward modeling based on the principle of equivalent eddy current;

[0107] Forward modeling is performed using the equivalent eddy current principle described in this invention to quickly obtain the theoretical response. Calculate the background field, anomaly field, and total field;

[0108] Constructing the objective function and performing simulated annealing inversion;

[0109] Construct the inversion objective function and use the simulated annealing algorithm for inversion iteration:

[0110] Set initial temperature And randomly generate a set of initial model parameters. .

[0111] Perform forward modeling to obtain And calculate the fitness of the current model (i.e., the objective function value). ).

[0112] like Less than the preset precision (e.g.) If the temperature is too low, the calculation should be repeated.

[0113] Randomly perturb the current model parameters to generate a new model, and calculate its objective function value.

[0114] Calculate the difference of the objective function .like Then accept the new model. Otherwise, calculate the probability density.

[0115] Repeat the above steps until the maximum number of iterations is reached (100 in this example) or the convergence condition is met.

[0116] Output the final inversion result.

[0117] Results analysis:

[0118] Effectiveness of multi-point joint constraints: As the number of measurement points involved in the inversion gradually increases from 1 to 14, the accuracy and stability of the inversion results significantly improve. When the number of measurement points is less than 10 (especially less than 8), the inversion results show large deviations over a wide initial range; for example, the errors in the inversion values ​​of Y-coordinate and resistivity increase significantly. This fully demonstrates that joint constraints of multi-point data are crucial for obtaining reliable inversion results.

[0119] Robustness of the method: Even when the initial model settings differ greatly from the actual geological conditions, the global search of the simulated annealing algorithm through multi-point joint constraints can still converge to a solution that is very close to the true value, indicating that the present invention has low dependence on the initial model and strong robustness.

[0120] Please refer to Figure 5 , Figure 5 This invention provides a structural block diagram of a borehole transient electromagnetic pseudo-3D data inversion device for multi-point joint detection; the specific device may include:

[0121] The data acquisition module 100 emits a pulsed magnetic field at the borehole opening to acquire the observation dataset;

[0122] Model building module 200 builds the initial inversion model and presets the values ​​of the model parameters;

[0123] The function calculation module 300, based on the equivalent eddy current principle, constructs the functional relationship between the model parameters and the forward modeling theoretical data to obtain the inversion objective function. The construction of the functional relationship between the model parameters and the forward modeling theoretical data includes:

[0124] Calculate the transient electromagnetic response of the background field in the entire space;

[0125] The induced eddy current generated by the abnormal body after the current is turned off is equivalent to a current loop, and the abnormal field response generated by the current loop is calculated using the Biot-Savart law.

[0126] The transient electromagnetic response is superimposed on the abnormal field response to obtain the total field response, which is used as forward modeling data.

[0127] The iteration module 400 uses the simulated annealing algorithm to iteratively optimize the inversion objective function using the inversion initial model as the initial condition for iteration, obtains the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstructs the model parameters based on the electrical parameters.

[0128] This embodiment of a multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion device is used to implement the aforementioned multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion method. Therefore, the specific implementation of the multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion device can be found in the embodiment section of the multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion method above. For example, the data acquisition module 100, model construction module 200, function calculation module 300, and iteration module 400 are respectively used to implement steps S101, S102, S103, and S104 in the aforementioned multi-point joint detection borehole transient electromagnetic pseudo-3D data inversion method. Therefore, its specific implementation can be referred to the description of the corresponding embodiments, and will not be repeated here.

[0129] To implement the above embodiments, this application also proposes an electronic device, including: a processor and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0130] To implement the above embodiments, this application also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0131] To implement the above embodiments, this application also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0132] The collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in this application all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0133] It should be noted that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. Furthermore, such collection / sharing should only be conducted after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes authorization of relevant user information before the user uses the function. In addition, any necessary steps must be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their privacy policies and procedures.

[0134] This application is intended to provide an implementation scheme for users to selectively prevent the use or access to their personal information data. Specifically, this disclosure is intended to provide hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, risks can be minimized by restricting data collection and deleting data. Furthermore, where applicable, such personal information is de-identified to protect user privacy.

[0135] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0136] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0137] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0138] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0139] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0140] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0141] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0142] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for borehole transient electromagnetic quasi-3D data inversion of multi-point joint sounding, characterized in that, include: A pulsed magnetic field is emitted at the borehole opening to obtain an observation dataset, including: A pulsed magnetic field is emitted at the borehole opening, and multiple measuring points are set up inside the borehole to measure the secondary magnetic field induced by the underground conductive geological body. The secondary magnetic field data from multiple measuring points are used as the observation dataset. Construct an initial inversion model and preset the values ​​of the model parameters; Based on the equivalent eddy current principle, a functional relationship between the model parameters and the forward modeling theoretical data is constructed. Then, based on the difference between the observed dataset and the forward modeling theoretical data, the inversion objective function is obtained. The construction of the functional relationship between the model parameters and the forward modeling theoretical data includes: Calculate the transient electromagnetic response of the background field in the entire space; The induced eddy current generated by the abnormal body after the current is turned off is equivalent to a current loop, and the abnormal field response generated by the current loop is calculated using the Biot-Savart law. The transient electromagnetic response is superimposed with the abnormal field response to obtain the total field response, which is used as forward modeling data. The simulated annealing algorithm is used to iteratively optimize the inversion objective function with the inversion initial model as the initial condition for iteration, obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstruct the model parameters based on the electrical parameters. The formula for calculating the background field is: wherein , , is x , y , z a unit vector in the direction of, is the emitted magnetic moment, , magnetic permeability, electrical conductivity, is time, is the distance from the observation point to the source point; The formula for calculating the abnormal field is: wherein, is the vacuum permeability, is the equivalent current, is the current loop infinitesimal vector, is the vector from the sphere center to the observation point, is the distance from the sphere center to the observation point.

2. The method of claim 1, wherein, The step of employing simulated annealing algorithm, using the initial inversion model as the initial condition for iteration, to iteratively optimize the inversion objective function includes: Set initial control parameters and randomly generate initial model parameters; Perform forward modeling and evaluate the fitness of the current model parameters. If the fitness meets the accuracy requirements, terminate the iteration and output the results. If the fitness does not meet the accuracy requirements, the current model parameters are randomly perturbed to generate a new model, and the fitness of the new model is calculated. Determine whether the fitness of the new model meets the standard, gradually reduce the control parameters, and repeat the iterative calculation until the termination condition is met.

3. The method of claim 2, wherein, The control parameters are updated according to an exponential decay law, and the calculation formula is as follows: wherein, is a cooling factor between 0 and 1, is the number of iterations, is the control parameter at the iteration, is the control parameter at the iteration.

4. The method of claim 1, wherein, The model parameters include the resistivity of the background medium, the resistivity of the anomalous body, the diameter of the anomalous body, and the three-dimensional spatial coordinates of the center of the anomalous body.

5. A device for borehole transient electromagnetic quasi-3D data inversion of multi-point joint sounding, characterized in that, include: The data acquisition module emits a pulsed magnetic field at the borehole opening to acquire the observation dataset, including: A pulsed magnetic field is emitted at the borehole opening, and multiple measuring points are set up inside the borehole to measure the secondary magnetic field induced by the underground conductive geological body. The secondary magnetic field data from multiple measuring points are used as the observation dataset. The model building module constructs the initial inversion model and presets the values ​​of the model parameters. The function calculation module, based on the equivalent eddy current principle, constructs the functional relationship between the model parameters and the forward modeling theoretical data, and obtains the inversion objective function based on the difference between the observed dataset and the forward modeling theoretical data. The construction of the functional relationship between the model parameters and the forward modeling theoretical data includes: Calculate the transient electromagnetic response of the background field in the entire space; The induced eddy currents generated by the anomalous body after the current is turned off are equivalent to a current loop, and the anomalous field response generated by the current loop is calculated using the Biot-Savart law. The formula for calculating the background field is: in, , , for x , y , z The unit vector of direction. To emit magnetic moments, , magnetic permeability Electrical conductivity For time, The distance from the observation point to the source point; The formula for calculating the abnormal field is: in, The permeability of free space, For equivalent current, For the current loop infinitesimal vector, The vector from the center of the sphere to the observation point. The distance from the center of the sphere to the observation point; The transient electromagnetic response is superimposed with the abnormal field response to obtain the total field response, which is used as forward modeling data. The iterative module employs a simulated annealing algorithm, using the initial inversion model as the initial condition for iteration, to iteratively optimize the inversion objective function, obtain the electrical parameters corresponding to the minimum value of the inversion objective function, and reconstruct the model parameters based on the electrical parameters.

6. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-4.

Images