A power source high temperature superconducting transient electromagnetic detection method and system

Abstract

The application relates to the field of geological exploration, in particular to a high-temperature superconducting transient electromagnetic detection method and system of an electric source, the method is applied to a magnetic field signal receiving end, original time domain magnetic field signals are collected through a built-in high-temperature superconducting magnetometer receiving array; a primary field adaptive compensation model with a nonlinear geophysical constraint term is constructed; the nonlinear geophysical constraint term is determined based on a nonlinear integration relationship of stratum resistivity and depth; global residual constraints and deep late path weighted residual constraints are set, and the primary field adaptive compensation model is adaptively iteratively fitted to determine a theoretical primary field signal to be stripped in the original time domain magnetic field signal; the original time domain total magnetic field signal is subtracted from the theoretical primary field signal, a primary field residual interference component is stripped, and a pure secondary field magnetic field signal is obtained; the pure secondary field magnetic field signal is used to construct a non-integral full-area apparent resistivity inversion model, and a stratum three-dimensional electrical structure is solved.

Description

Technical Field

[0001] This application relates to the field of geological exploration, and more specifically, to a method and system for detecting high-temperature superconducting transient electromagnetic signals using an electrical source. Background Technology

[0002] The transient electromagnetic method using electrical sources is a mainstream geophysical technology for deep and large-scale geological exploration. It uses a grounded long conductor as the emission source and can excite a uniform electromagnetic field throughout the entire area. It has good response characteristics to geological bodies with high and low resistivity anomalies and is a core technical means for deep resource exploration and regional tectonic detection.

[0003] Currently, conventional transient electromagnetic detection systems using electrical sources generally employ induction coils as receiving probes. Electromagnetic signals are acquired by measuring the induced electromotive force (dB / dt), and the induced magnetic field is then calculated through integration, ultimately achieving full-area apparent resistivity inversion imaging. However, as exploration depths continue to extend to depths of 2km and large areas of 10km, the inherent limitations of traditional induction coil receiving systems become increasingly prominent, severely restricting the accuracy and capability of deep-penetration detection.

[0004] Meanwhile, to address issues such as primary field interference from electrical sources, shallow blind zones, and signal distortion, the mainstream existing technology involves primary field compensation at the transmitter. This is achieved by using a dedicated compensation transmitter to cancel and compensate for the primary field signal at the source. However, this technology focuses on modifying the transmission system, requiring specialized hardware. It is incompatible with mainstream commercial transient electromagnetic instruments, resulting in high equipment modification costs, poor versatility, and severe limitations on field deployment, hindering large-scale engineering applications. The industry urgently needs a new transient electromagnetic exploration method that is compatible with general-purpose commercial instruments, achieves accurate primary field compensation at the receiver, and enables high-precision detection at both shallow and deep layers.

[0005] The prior art most similar to this application mainly falls into two categories: traditional induction coil type electric source transient electromagnetic detection technology and transmitter-end primary field compensation electric source transient electromagnetic technology. Both types of prior art have multiple inherent technical bottlenecks, the specific defects of which are as follows: First, there is an irreconcilable contradiction between sensor bandwidth and sensitivity. The sensitivity of conventional induction coils is negatively correlated with the operating frequency, resulting in extremely low sensitivity for detecting low-frequency deep signals. The industry generally improves low-frequency sensitivity by increasing the number of coil turns and increasing the receiving area, but this significantly increases the coil inductance and parasitic capacitance, compressing the bandwidth and causing severe loss of fine, shallow high-frequency geological signals corresponding to early delays, making it impossible to achieve integrated detection of deep and shallow layers.

[0006] Second, the signal-to-noise ratio of late-stage signals is extremely low, limiting exploration depth. The response of deep geological bodies corresponds to weak low-frequency transient electromagnetic signals in the late stage. Induction coils have weak ability to sense low-frequency signals, and the effective signals in the late stage are easily drowned out by environmental noise, resulting in a very poor signal-to-noise ratio. This makes it impossible to identify weak geological anomalies at a depth of 2km, making it difficult to increase the exploration radius and depth.

[0007] Third, traditional techniques directly acquire induced electromotive force (dB / dt). This parameter presents mathematical problems with multiple solutions and no solutions in the calculation of apparent resistivity. It must be converted into an induced magnetic field (B) through integration before inversion. The integration process continuously accumulates and amplifies the original noise error. Especially for weak deep late-stage signals, the error grows exponentially, leading to distortion in deep imaging and low accuracy in geological interpretation.

[0008] Fourth, existing primary field compensation schemes all focus on transmitter optimization and rely on hardware modifications to dedicated compensation transmitters, which have significant limitations: First, the equipment has poor versatility, requiring dedicated transmitter equipment and being incompatible with mainstream commercially available transient electromagnetic instruments with conventional electrical sources. Existing general-purpose equipment cannot be reused, resulting in extremely high engineering modification costs. Second, the field adaptability is weak, with fixed compensation parameters that cannot be adaptively adjusted based on complex terrain, exploration distance, and differences in stratum electrical properties, leading to significant compensation failure issues in long-distance exploration scenarios (up to 10km). Third, the system is highly complex, requiring extensive hardware and software modifications to the transmitter, cumbersome equipment debugging, and low operational efficiency, making it difficult to adapt to large-scale, large-scale deep exploration operations.

[0009] In summary, existing technologies are constrained by the physical defects of induction coil sensors and indirect conversion mechanisms, resulting in problems such as imbalance between shallow and deep detection, poor signal quality in the later stages, and low accuracy at depths. On the other hand, existing primary field compensation schemes rely on dedicated hardware modifications at the transmitting end, which have poor versatility, high cost, and weak adaptability, and cannot meet the multiple engineering requirements of adapting to general equipment, accurate primary field compensation, high-precision detection of shallow and deep layers, and large-scale exploration at great depths. Summary of the Invention

[0010] In view of this, this application provides a method and system for detecting high-temperature superconducting transient electromagnetic signals using an electrical source, in order to solve the above-mentioned technical problems.

[0011] The technical solution provided in this application is as follows: In a first aspect, this application provides a method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source, applied at a magnetic field signal receiving end, the method comprising: The original time-domain magnetic field signal is acquired by the built-in high-temperature superconducting magnetometer receiving array; A primary field adaptive compensation model with nonlinear geophysical constraints is constructed; the nonlinear geophysical constraints are determined based on the depth nonlinear integral relationship of formation resistivity. Global residual constraints and deep late-stage trace weighted residual constraints are established, and the primary field adaptive compensation model is adaptively iteratively fitted to determine the theoretical primary field signal to be stripped from the original time-domain magnetic field signal. Wherein, the global residual constraint is a threshold restriction on the fitting residual between the original time-domain magnetic field signal and the theoretical primary field signal; the deep late-stage trace weighted residual constraint is a threshold restriction on the fitting residual after weighting in the deep late-stage period; The original total magnetic field signal in the time domain is compared with the theoretical first field signal to remove the residual interference components of the first field and obtain the pure second field magnetic field signal. Using the pure secondary field magnetic field signal, an inversion model of apparent resistivity without integration is constructed for the entire area to solve for the three-dimensional electrical structure of the formation.

[0012] In one possible implementation, the theoretical primary field signal output in the primary field adaptive compensation model is determined based on the geometric attenuation factor related to the transmission and reception distance, the timing of the step current output by the magnetic field signal transmitter, the formation resistivity, and a preset time-varying attenuation dynamic compensation term. The time-varying attenuation dynamic compensation term automatically updates its coefficient step size based on the residual gradient during the iterative fitting process.

[0013] One possible implementation, which involves adaptive iterative fitting of the primary field adaptive compensation model, further includes: The nonlinear geophysical constraint terms are updated using the corrected formation resistivity parameters fitted in the previous iteration to correct the primary field adaptive compensation model.

[0014] In one possible implementation, the global residual constraint is expressed as:

[0015] In the formula, Represents the original time-domain magnetic field signal. Represents a theoretical first-order field signal. This represents the effective secondary field underground, and ε1 represents the preset global residual threshold. Indicates the first i Each window is a central time.

[0016] In one possible implementation, the weighted residual constraint for the deep late-stage trace is expressed as:

[0017] In the formula, Represents the original time-domain magnetic field signal. Represents a theoretical first-order field signal. Indicates the effective secondary field underground. This represents the weighting coefficients for late-stage deep signals. t Indicates the center time of the window. This represents the preset weighted residual threshold for deep late-stage traces.

[0018] In one possible implementation, after determining the theoretical primary field signal to be stripped from the original time-domain magnetic field signal, the method further includes: Secondly, this application provides an electric source high-temperature superconducting transient electromagnetic detection system, including a transmitter and a receiver; the transmitter is equipped with a high-power electric source transmitting unit; the receiver is equipped with a high-temperature superconducting magnetometer receiving array and a data processing terminal; The high-power electrical source transmitting unit is used to transmit bipolar step pulse currents into the ground to excite electromagnetic fields; The high-temperature superconducting magnetometer receiving array is used to directly acquire the original time-domain magnetic field signal; The receiving end data processing terminal is used to execute the high-temperature superconducting transient electromagnetic detection method of the electrical source as described in any of the first aspects, and output a pure secondary field magnetic field signal.

[0019] In one possible implementation, a timing synchronization unit is also included between the transmitter and receiver, configured with wired cable synchronization, GPS + BeiDou satellite synchronization, radio synchronization, and quartz clock timekeeping synchronization modes, which are used to automatically switch the synchronization channel when the wired link is broken or the satellite signal is weak.

[0020] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: This application adopts an innovative architecture that combines primary field adaptive compensation at the receiver with direct magnetic field acquisition by a high-temperature superconducting magnetometer. It abandons the traditional hardware compensation mode at the transmitter and introduces a two-layer iterative algorithm with nonlinear resistivity integral constraints of the formation. Combined with the dual convergence criteria of global residual and deep late-stage weighted residual, it can accurately remove residual interference of the primary field at the receiver. It can be compatible with mainstream commercial electrical source exploration instruments without modifying the transmitter hardware, which greatly reduces the hardware modification cost and application threshold. At the same time, it effectively solves the technical problems of primary field compensation failure and false convergence of deep signals in 10km-level long-distance exploration scenarios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an electrical source high-temperature superconducting transient electromagnetic detection system provided in Embodiment 1 of this application.

[0022] Figure 2 This is a schematic diagram of the scene arrangement of the transient electromagnetic detection system for an electrical source provided in Embodiment 1 of this application.

[0023] Figure 3This is a flowchart of a high-temperature superconducting transient electromagnetic detection method using an electrical source, provided in Embodiment 1 of this application. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0025] Example 1 See Figure 1 This is a schematic diagram of the structure of a high-temperature superconducting transient electromagnetic detection system with an electrical source, provided in Embodiment 1 of this application. Figure 1 As shown, the system includes a transmitter, a receiver, and a timing synchronization unit.

[0026] The aforementioned transmitter is equipped with a high-power electrical source transmitter unit, which can be deployed according to the geological conditions of the work area, and is used to output bipolar step pulse current.

[0027] Optionally, the aforementioned high-power electric transmitting unit can be a grounded long-conductor electric transmitting source, with an adjustable transmitting current amplitude of 100~300A, a pulse width of 50~500μs, and a transmitting frequency of 2.5~25Hz. The excited electromagnetic field effectively covers a radius of 0~10km, uniformly exciting strata at depths of 0~2km underground, ensuring that shallow, intermediate, and deep geological bodies can all generate a complete and stable secondary eddy current field response, providing sufficient excitation energy for ultra-large-scale deep exploration.

[0028] The aforementioned receiver incorporates a high-temperature superconducting magnetometer array, replacing traditional induction coils. This eliminates the need to increase the number of coil turns to improve low-frequency response, fully preserving the fine high-frequency signals from shallow, early-delay areas and accurately capturing the weak low-frequency magnetic fields from deep, late-delay areas. The device directly outputs the original time-domain magnetic field B(t) without undergoing differential amplification and conversion to dB / dt, thus eliminating additional noise introduced by differential operations at the acquisition source.

[0029] Optionally, the above-mentioned high-temperature superconducting magnetometer receiving array can be deployed as a distributed array with a liquid nitrogen-cooled 77K high-temperature superconducting magnetometer HTS-SQUID, with a noise floor ≤8fT / √Hz@1Hz, an operating frequency band of 0~1MHz, and uniform high sensitivity across the entire frequency band.

[0030] The aforementioned timing synchronization unit includes a synchronization cable. The synchronization link supports synchronization modes such as cable, GPS+BeiDou, radio, and quartz clock. When the wired link is interrupted or the satellite signal is weak in canyons / dense forests, the system automatically switches the synchronization channel, with a synchronization error ≤0.5μs after switching. Before each data acquisition starts, the system automatically completes wired synchronization and satellite synchronization difference calibration to eliminate timing offsets in each receiving unit of the distributed array, ensuring a unified time reference for the magnetic field signal of the 10km ultra-long survey line array. The system primarily uses wired coaxial cable hardware timing synchronization, supplemented by GPS / BeiDou dual-mode satellite timing, employing a dual-redundant synchronization mechanism, resulting in a total system timing synchronization error ≤0.5μs.

[0031] For example, in a real-world application scenario, such as Figure 2 As shown, transmitting electrodes A and B are arranged, with a transmitting electrode distance L typically 1-3 km between them. A transient electromagnetic transmitter Tx is positioned between A and B. A transmitting wire connects the transient electromagnetic transmitter Tx and AB. Transmitting measurement points Stn are designed, distributed around the transmitting system (at a distance greater than 30 m from the transmitter source) according to a certain line spacing (typically 50-200 m) and point spacing (20-50 m). A superconducting sensor SQUID is placed at the measurement point, kept horizontal. A transient electromagnetic receiver is positioned at a distance greater than 5 m from the superconducting sensor SQUID. A connecting cable connects the transient electromagnetic receiver Rx and the superconducting sensor SQUID. A synchronization cable connects the transient electromagnetic transmitter Tx and the transient electromagnetic receiver Rx to maintain synchronization (or synchronization can be achieved using GPS, BeiDou, etc.), with a synchronization accuracy typically greater than 200 ns. A transient electromagnetic transmitter (Tx) is powered in the transmission line, producing a bipolar trapezoidal waveform with a transmission current ranging from several to tens of amperes. Acquisition parameters are set according to actual requirements. A transient electromagnetic receiver (Rx) is used to acquire the induced magnetic field signal via a superconducting sensor (SQUID). After acquisition, the acquisition system is moved to the next measurement point until all measurement points have completed data acquisition.

[0032] Compared with the prior art, the technical solution of Embodiment 1 of this application has the following beneficial effects: Existing conventional transient electromagnetic methods are limited by the emission source and sensor, resulting in limited detection depth, a small planar measurable range, and a maximum distance between points not exceeding 3 km. This application proposes a high-temperature superconducting transient electromagnetic method based on an electric emission source. Firstly, it utilizes high-power electric source emission technology to excite deep targets, expanding the planar radiation range. Secondly, it employs a high-temperature superconducting magnetometer as a sensor to directly measure the magnetic field, effectively acquiring high signal-to-noise ratio weak signals from deep objects in the late stages. This overcomes the inherent limitations of inductive sensors in terms of depth resolution and the difficulty in achieving full-range measurement due to low sensitivity.

[0033] Furthermore, such as Figure 1As shown, the receiving end is also equipped with a data processing terminal. This application abandons the traditional hardware compensation mode of the transmitting end and realizes primary field adaptive compensation at the software algorithm level of the receiving end. It does not require any modification to the hardware of the transmitting equipment and is fully compatible with commercial general-purpose instruments. The specific steps are as follows: Based on the real-time collected raw magnetic field data, combined with the transmission current time series parameters, transmission and reception distance, terrain elevation, and prior information on the electrical properties of the strata, a theoretical model of the primary field is constructed; by iteratively fitting the difference between the measured signal and the theoretical primary field signal, the residual interference of the primary field is adaptively removed, and the signal distortion caused by the superposition of the primary field is accurately compensated; for long-distance and deep exploration scenarios, the compensation coefficient is dynamically optimized to solve the problems of primary field compensation failure and signal offset in large-scale exploration of 10km, and the pure secondary field effective signal is retained. The adaptive iterative primary field compensation algorithm with the nonlinear resistivity depth constraint of the charged layer is built in, and a dual-layer dynamic compensation coefficient control mechanism and a dual joint convergence criterion of global residual + deep late-stage weighted residual are integrated.

[0034] The following detailed description of the method for performing precise field compensation at the receiving end proposed in this application, in conjunction with the method embodiments, is provided to fully clarify the technical solution for which this application seeks protection.

[0035] Example 2 See Figure 2 This is a flowchart of a high-temperature superconducting transient electromagnetic detection method using an electrical source, provided in Embodiment 2 of this application. The above method is applied to the receiving end of the aforementioned electromagnetic detection system. Figure 2 As shown, the specific implementation steps of the above method include: Step 101: Acquire the original time-domain magnetic field signal through the built-in high-temperature superconducting magnetometer receiving array.

[0036] Step 102: Construct a primary field adaptive compensation model with nonlinear geophysical constraints.

[0037] Specifically, the above-mentioned first-order adaptive compensation model is expressed as:

[0038] In the formula, This represents the theoretical first-order field signal output by the model. t Indicates the center time of the window. r Indicates the sending and receiving distance. Indicates the transmission and reception distance r Relevant geometric attenuation coefficient, r The maximum value is 10km. This indicates the timing of the transmitter's output step current. This represents the electrical conductivity at a depth z in the underground strata, derived from the stratum resistivity. The nonlinear mapping yields a unique nonlinear geophysical constraint term, which is original to this application. , It represents the time-varying decay dynamic compensation coefficient, which is adaptively and dynamically adjusted during the iterative process and is not a fixed constant.

[0039] Step 103: Establish global residual constraints and deep late-stage trace weighted residual constraints, and perform adaptive iterative fitting on the above-mentioned primary field adaptive compensation model to determine the theoretical primary field signal to be stripped from the above-mentioned original time-domain magnetic field signal.

[0040] This application introduces a depth nonlinear integral constraint term for formation resistivity to accurately characterize the attenuation law of electromagnetic fields penetrating layered nonlinear formations at a distance of 10km, thus solving the technical defect that linear models cannot fit deep and long-distance distorted primary fields.

[0041] The algorithm employs a double-layered iterative loop, which differs from existing techniques that use static fitting with fixed parameters, as detailed below: Outer layer cyclic update of formation nonlinear resistivity constraint terms The primary field theory model is corrected using the formation electrical properties obtained from the previous inversion. The time-varying attenuation coefficient is dynamically adjusted by the inner layer circulation. , In each iteration, the coefficient step size is automatically updated based on the measured magnetic field residual gradient. When the residual value is large, the step size is increased to accelerate convergence, and when the residual approaches the threshold, the step size is decreased to improve fitting accuracy.

[0042] Conventional linear fitting uses only a single global residual threshold as the convergence condition, which easily leads to spurious convergence problems such as "shallow residuals meeting the threshold, but deep late-stage residuals exceeding the threshold." This application constructs a dual criterion of global residual constraints and deep late-stage trace weighted residual constraints. Both conditions must be met simultaneously for the iteration to terminate. Condition 1 is a global residual constraint, expressed as:

[0043] In the formula, This represents the global residual threshold, which is fixed at 0.005nT. This represents the measured total magnetic field of the superconducting system, i.e., the original time-domain magnetic field signal mentioned above. This indicates the effective secondary field underground. N Indicates the number of samples. Indicates the first i Each window is a central time.

[0044] Condition 2 is a weighted residual constraint for deep late-stage traces, expressed as:

[0045] In the formula, This represents the weighting coefficients for deep late-stage signals, which increase exponentially with increasing delay. The weighted residual threshold for deep late-stage traces. It is specifically designed to strengthen convergence constraints for weak signals at depths after 100ms, thus eliminating false convergence in long-distance exploration.

[0046] Step 104: Perform a difference operation between the original total magnetic field signal in the time domain and the theoretical primary field signal mentioned above to remove the residual interference components of the primary field and obtain the pure secondary field magnetic field signal.

[0047] After iterative convergence, the corrected subsurface secondary magnetic field is obtained, expressed as:

[0048] Step 105: Construct a non-integral full-area apparent resistivity inversion model using the pure secondary field magnetic field signal mentioned above, and solve for the three-dimensional electrical structure of the formation.

[0049] In this embodiment, the formation nonlinear resistivity is updated by inversion using the corrected pure secondary field magnetic field signal. Repeat the above steps until the overall three-dimensional electrical structure of the formation is stable.

[0050] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: This application presents a transient electromagnetic detection architecture based on an electric source transmitter, a receiver with primary field compensation, and a high-temperature superconducting magnetometer for direct magnetic field acquisition. This architecture differs from all existing technologies that rely on indirect acquisition via induction coils and hardware compensation at the transmitter. The high-temperature superconducting magnetometer's high sensitivity and ultra-wide bandwidth across the entire frequency band eliminate the need to increase low-frequency sensitivity by adding coil turns. It fully preserves detailed shallow geological information while accurately capturing weak late-stage signals from deep layers, completely resolving the problem of traditional technologies failing to simultaneously address both shallow and deep detection needs. Directly acquiring raw magnetic field physical quantities eliminates the integration and conversion process, preventing the accumulation of integration errors at the source. Simultaneously, it avoids the defects of multiple solutions and no solutions in the calculation of induced electromotive force and apparent resistivity, significantly improving the accuracy of deep strata inversion and the reliability of geological imaging.

[0051] Abandoning the dedicated hardware compensation scheme at the transmitter, this method achieves precise adaptive compensation at the receiver through algorithms, eliminating the need to modify the transmitting equipment. It is compatible with all mainstream commercial electrical source instruments, resolving the issues of poor versatility and limited applicability of traditional transmitter compensation technologies. Utilizing the ultra-wideband, low-noise, and high-sensitivity characteristics of a high-temperature superconducting magnetometer, it directly acquires the raw magnetic field signal, completely eliminating the bandwidth-sensitivity discrepancy and integral conversion errors of the sensor. Through coordinated hardware and software optimization, it achieves high-precision and stable exploration with an ultra-large detection radius of 10km and an ultra-large detection depth of 2km, breaking through the performance limits of existing transient electromagnetic technologies for electrical sources.

[0052] Example 3 To further verify the superiority of the technical solution of this application compared with the prior art, Embodiment 3 of this application provides a specific application scenario for using the high-temperature superconducting transient electromagnetic method with receiver compensation of this application. A deep metal mineral exploration project is used as an example for further illustration.

[0053] In a deep metal mineral exploration project, with a target exploration coverage radius of 10km and an effective detection depth of 0-2km, mainstream commercially available electric transient electromagnetic transmission equipment was used on-site. The high-temperature superconducting transient electromagnetic method with receiver compensation of this invention was employed. The specific steps are as follows: 1. Directly reuse existing commercial electrical source transmitting equipment, deploy conventional grounded long conductor transmitting sources with a rated transmitting current of 200A, without any hardware modification or compensation module installation; deploy 12 sets of high-temperature superconducting magnetometer receiving arrays within a 10km full-area exploration range, with timing synchronization accuracy ≤1μs, to ensure synchronous acquisition of signals across the entire area.

[0054] 2. Set the transmission time base to 100ms (fundamental frequency 2.5Hz) and output a stable bipolar step electromagnetic pulse to complete the full-domain electromagnetic excitation of the strata with a radius of 10km and a depth of 2km.

[0055] 3. The original signal of the underground secondary field induced magnetic field is directly acquired by a high-temperature superconducting magnetometer with an acquisition time of 100ms. It fully covers the shallow early-delay fine signal and the deep late-delay weak signal, and the acquisition is distortion-free across the entire frequency band without signal loss.

[0056] 4. Based on the transmission timing, transmission and reception distance, and prior parameters of the regional strata, a primary field theoretical model is constructed. Through adaptive iterative fitting, residual interference in the primary field is removed, and accurate signal compensation is achieved while retaining the effective secondary field signal.

[0057] (1) Import the transmission current timing, the transmission and reception distance of the survey line, and the prior resistivity profile of the strata in the work area to construct a primary field theoretical model with integral constraint of nonlinear conductivity at the depth of the charged layer; (2) Start a double-layer iterative loop, dynamically adjust the time-varying attenuation compensation coefficient, and adopt a dual joint convergence criterion of global residual threshold ε1=0.005nT and deep late-stage weighted residual threshold ε2=0.001nT; (3) The total time for algorithm iteration convergence is 37s. After stripping the theoretical primary field, the pure underground secondary field magnetic field is output. The primary field fitting residual at the 10km far end measuring point is only 1.09%, and the signal-to-noise ratio of the deep late signal is 39.1dB. 5. Based on the compensated original magnetic field data, noise reduction and calibration are carried out directly to construct a non-integral apparent resistivity inversion model and complete continuous imaging of the entire stratigraphy at a depth of 0-2km.

[0058] 6. This embodiment is fully compatible with commercially available general-purpose launch equipment, requiring no hardware modification and significantly reducing construction costs. Compared with traditional launch end compensation schemes, the equipment's versatility is significantly improved, and its adaptability is stronger. It can accurately identify concealed mineralization anomalies at a depth of 2km and achieve high-precision exploration across a 10km ultra-large radius, taking into account both shallow fine detection and deep, large-depth exploration needs.

[0059] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source, characterized in that, Applied to a magnetic field signal receiving end, the method includes: The original time-domain magnetic field signal is acquired by the built-in high-temperature superconducting magnetometer receiving array; A primary field adaptive compensation model with nonlinear geophysical constraints is constructed; the nonlinear geophysical constraints are determined based on the depth nonlinear integral relationship of formation resistivity. Global residual constraints and deep late-stage trace weighted residual constraints are established, and the primary field adaptive compensation model is adaptively iteratively fitted to determine the theoretical primary field signal to be stripped from the original time-domain magnetic field signal. Wherein, the global residual constraint is a threshold restriction on the fitting residual between the original time-domain magnetic field signal and the theoretical primary field signal; the deep late-stage trace weighted residual constraint is a threshold restriction on the fitting residual after weighting in the deep late-stage period; The original total magnetic field signal in the time domain is compared with the theoretical first field signal to remove the residual interference components of the first field and obtain the pure second field magnetic field signal. Using the pure secondary field magnetic field signal, an inversion model of apparent resistivity without integration is constructed for the entire area to solve for the three-dimensional electrical structure of the formation.

2. The method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source according to claim 1, characterized in that, In the first-field adaptive compensation model, the output theoretical first-field signal is determined based on the geometric attenuation factor related to the transmission and reception distance, the timing of the step current output by the magnetic field signal transmitter, the formation resistivity, and the preset time-varying attenuation dynamic compensation term. The time-varying attenuation dynamic compensation term automatically updates its coefficient step size based on the residual gradient during the iterative fitting process.

3. The method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source according to claim 1, characterized in that, Adaptive iterative fitting of the first-order adaptive compensation model further includes: The nonlinear geophysical constraint terms are updated using the corrected formation resistivity parameters fitted in the previous iteration to correct the primary field adaptive compensation model.

4. The method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source according to claim 1, characterized in that, The global residual constraint is expressed as: In the formula, Represents the original time-domain magnetic field signal. Represents a theoretical first-order field signal. This represents the effective secondary field underground, and ε1 represents the preset global residual threshold. Indicates the first i Each window is a central time.

5. The method for detecting high-temperature superconducting transient electromagnetic signals using an electrical source according to claim 1, characterized in that, The weighted residual constraint for the deep late-stage trace is expressed as: In the formula, Represents the original time-domain magnetic field signal. Represents a theoretical first-order field signal. Indicates the effective secondary field underground. This represents the weighting coefficients for late-stage deep signals. t Indicates the center time of the window. This represents the preset weighted residual threshold for deep late-stage traces.

6. A high-temperature superconducting transient electromagnetic detection system with an electrical source, characterized in that, It includes a transmitter and a receiver; the transmitter is equipped with a high-power electrical source transmitting unit; the receiver is equipped with a high-temperature superconducting magnetometer receiving array and a data processing terminal. The high-power electrical source transmitting unit is used to transmit bipolar step pulse currents into the ground to excite electromagnetic fields; The high-temperature superconducting magnetometer receiving array is used to directly acquire the original time-domain magnetic field signal; The receiving end data processing terminal is used to execute the high-temperature superconducting transient electromagnetic detection method of the electrical source as described in any one of claims 1 to 5, and output a pure secondary field magnetic field signal.

7. The high-temperature superconducting transient electromagnetic detection system with an electrical source according to claim 6, characterized in that, The transmitter and receiver also include a timing synchronization unit, which is configured with wired cable synchronization, GPS + Beidou satellite synchronization, radio synchronization and quartz clock timekeeping synchronization modes, and is used to automatically switch the synchronization channel when the wired link is broken or the satellite signal is weak.

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