Dual-receiving transient electromagnetic device and method

Abstract

The invention provides a dual-receiving transient electromagnetic device and a dual-receiving transient electromagnetic method. The double-receiving transient electromagnetic device comprises a transmitter, a transmitting coil, a first magnetic field receiver, a second magnetic field receiver and a receiver, and the first magnetic field receiver and the second magnetic field receiver are placed in the transmitting coil and outside the transmitting coil respectively. The positions of the first magnetic field receiver and the second magnetic field receiver are adjusted, so that the primary electromagnetic fields on the first magnetic field receiver and the second magnetic field receiver are equal in size and opposite in direction, and the primary electromagnetic fields in the electrical signals received by the receivers can be offset finally, so that accurate secondary electromagnetic field signals can be displayed on the receivers. Therefore, accurate geophysical survey can be carried out through the accurate secondary electromagnetic field signals.

Description

Technical Field

[0001] The invention relates to the field of geophysical exploration, and in particular to a dual-receiving transient electromagnetic device and a dual-receiving transient electromagnetic method. Background Art

[0002] Transient electromagnetic method, also known as time domain electromagnetic method, is a geophysical exploration method, mainly used in archaeological exploration, mineral exploration, engineering geological exploration and other fields. Transient electromagnetic method is based on the principle of electromagnetic induction and the electrical and magnetic differences of underground media to explore geophysics. Transient electromagnetic method is based on transient electromagnetic device, which includes: transmitting system, transmitting coil, receiving coil and receiver. The specific implementation method is that the transmitting system generates a transmitting signal and transmits it to the transmitting coil. Then the transmitting coil will form a primary electromagnetic field with a certain intensity in space. The primary electromagnetic field will induce weak eddy currents in the underground medium with electrical and magnetic differences. The eddy current generates a secondary electromagnetic field, which is different from the primary electromagnetic field. The secondary electromagnetic field generated by the underground medium can be used for geophysical exploration.

[0003] Conventional receiving coils often use multi-turn small coils, and most of them use overlapping loop devices. However, the mutual inductance between the transmitting coil and the receiving coil is strong. In addition, the receiving coil is seriously affected by the interference of the primary electromagnetic field, which affects the shutdown time. The early signal received by the receiver is seriously distorted, resulting in inaccurate shallow detection. Therefore, the actual use effect does not match the actual geological conditions.

[0004] Therefore, how to design a transient electromagnetic device and a transient electromagnetic method that can accurately measure secondary electromagnetic field signals has become one of the problems that technical personnel in this field need to solve urgently.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a dual-receiving transient electromagnetic device and a dual-receiving transient electromagnetic method, so as to solve the problem that the transient electromagnetic device in the prior art cannot accurately measure the secondary electromagnetic field signal.

[0007] To achieve the above-mentioned purpose and other related purposes, the present invention provides a dual-receiving transient electromagnetic device, which at least includes: a transmitter, a transmitting coil, a first magnetic field receiver, a second magnetic field receiver and a receiver; the transmitter is connected to the transmitting coil and is used to provide an electrical signal to the transmitting coil; the transmitting coil is used to transmit an electromagnetic field to the target object to be measured; the first magnetic field receiver is arranged in the area surrounded by the transmitting coil, is used to receive the magnetic field signal, and sends a first output electrical signal to the receiver; the second magnetic field receiver is arranged outside the area surrounded by the transmitting coil, is used to receive the magnetic field signal, and sends a second output electrical signal to the receiver; the receiver is connected to the first magnetic field receiver and the second magnetic field receiver respectively, and adds the first output electrical signal and the second output electrical signal.

[0008] Optionally, the shape of the transmitting coil is a circle, or the shape of the transmitting coil is any one of a regular polygon.

[0009] Optionally, both the first magnetic field receiver and the second magnetic field receiver are magnetic sensors.

[0010] Optionally, the first magnetic field receiver is located at the center of the transmitting coil.

[0011] To achieve the above-mentioned purpose and other related purposes, the present invention also provides a dual-receiving transient electromagnetic method, which at least includes: turning on the transmitter so that the transmitter sends an electrical signal to the transmitting coil; the transmitting coil generates a primary electromagnetic field; the target object to be measured generates a secondary electromagnetic field after receiving the primary electromagnetic field; the first magnetic field receiver receives the magnetic field signal in the space and sends a first output electrical signal to the receiver; the second magnetic field receiver receives the magnetic field signal in the space and sends a second output electrical signal to the receiver; the receiver performs an addition operation on the first output electrical signal and the second output electrical signal.

[0012] Optionally, when the target object to be measured is an underground medium, the transmitting coil, the first magnetic field receiver and the second magnetic field receiver are all attached to the ground surface; or when the target object to be measured is an above-ground medium, the transmitting coil, the first magnetic field receiver and the second magnetic field receiver are all attached to the surface of the landform.

[0013] Optionally, the positions of the first magnetic field receiver and the second magnetic field receiver are adjusted, and the first magnetic intensity and the second magnetic intensity are calculated so that the first magnetic intensity and the second magnetic intensity are equal in magnitude and opposite in direction, wherein the first magnetic intensity is the magnetic induction intensity generated by a primary electromagnetic field in the first magnetic field receiver, and the second magnetic intensity is the magnetic induction intensity generated by a primary electromagnetic field in the second magnetic field receiver.

[0014] More optionally, the calculation formulas of the first magnetic intensity and the second magnetic intensity are respectively:

[0015]

[0016] Wherein, B1 represents the first magnetic intensity, B2 represents the second magnetic intensity, n represents the number of turns of the transmitting coil, μ 0 represents the vacuum magnetic permeability, C represents the circumference of the transmitting coil, I represents the current in the transmitting coil, dl represents the line element vector of the transmitting coil, r 1 represents the vector distance from the first magnetic field receiver to the transmitting coil line element vector, r 2 Represents the vector distance from the second magnetic field receiver to the transmitting coil line element vector.

[0017] Optionally, the circumference, number of turns or shape of the transmitting coil is adjusted according to the exploration depth of the target object to be detected.

[0018] As described above, the dual-receiving transient electromagnetic device and method of the present invention have the following beneficial effects:

[0019] 1. The present invention sets two magnetic field receivers and places the two magnetic field receivers in the internal and external magnetic fields of the transmitting coil respectively. The magnetic induction intensity is calculated by a formula without relying on external conditions for the measurement of the magnetic induction intensity. The present invention can achieve that the magnetic induction intensity of the primary electromagnetic field on the two magnetic field receivers is equal in magnitude and opposite in direction.

[0020] 2. The receiver of the present invention performs an addition operation on the electrical signals output by the two magnetic field receivers, so that the primary electromagnetic field signals in the electrical signals output by the two magnetic field receivers are offset, and the receiver can then obtain an accurate secondary electromagnetic field signal. Therefore, the present invention can perform accurate geophysical surveys.

[0021] 3. The magnetic field receiver of the present invention adopts a magnetic sensor. Since the magnetic sensor has high accuracy and small size, the present invention can well reduce the mutual inductance between the magnetic sensor and the transmitting coil, so that the present invention can improve the accuracy of the secondary electromagnetic field signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a schematic diagram of a transient electromagnetic device.

[0023] Figure 2 It shows a first structural schematic diagram of the dual-receiving transient electromagnetic device of the present invention.

[0024] Figure 3 It shows a second structural schematic diagram of the dual-receiving transient electromagnetic device of the present invention.

[0025] Figure 4 Shown is the magnetic field distribution diagram of the transmitting coil of the present invention.

[0026] Figure 5 It is a schematic flow chart of the dual-receiving transient electromagnetic method of the present invention.

[0027] Figure 6 It shows a schematic diagram of the first surface installation of the dual-receiving transient electromagnetic device of the present invention.

[0028] Figure 7 It is a schematic diagram showing a second surface mounting method of the dual-receiving transient electromagnetic device of the present invention.

[0029] Component number description

[0030] 1 Transmitter

[0031] 2 Transmitter Coil

[0032] 3. First magnetic field receiver

[0033] 4 Second magnetic field receiver

[0034] 5 Receiver DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] See also Figure 1-Figure 7 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0037] like Figure 1 As shown in the figure, the transient electromagnetic method sends an electrical signal to the transmitting coil through the transmitter. The transmitting coil sends a primary electromagnetic field to the underground medium. The underground medium generates eddy currents due to the primary electromagnetic field. The eddy currents generate secondary electromagnetic fields. The secondary electromagnetic fields are received by the receiving coil and sent to the receiver. The receiver surveys the underground medium by analyzing the signals of the secondary electromagnetic fields. However, at the moment when the transmitter current is turned off, the primary electromagnetic field still remains in the receiving coil, so the early secondary electromagnetic field signals received by the receiving coil will be interfered by the primary electromagnetic field. Figure 1The transient electromagnetic device will cause serious distortion of the early underground medium signal.

[0038] In order to solve the interference of the primary electromagnetic field signal on the secondary electromagnetic field signal, the dual-receiving transient electromagnetic device of the present invention is provided with two magnetic field receivers for receiving magnetic field signals. By utilizing the opposite direction characteristics of the magnetic fields inside and outside the transmitting coil, the two magnetic field receivers are respectively placed inside and outside the transmitting coil, and the positions of the two magnetic field receivers are adjusted so that the magnetic induction intensity of the primary electromagnetic field in the two magnetic field receivers is the same in magnitude and opposite in direction. The receiver of the present invention adds the electrical signals received by the two magnetic field receivers. Then, under ideal conditions, the primary electromagnetic field signals in the magnetic field signals received by the two magnetic field receivers will cancel each other out, and then the secondary electromagnetic field signals received by the two magnetic field receivers can be used to accurately survey the target object to be measured.

[0039] Embodiment 1

[0040] like Figure 2 As shown, this embodiment provides a dual-receiving transient electromagnetic device, which includes: a transmitter 1, a transmitting coil 2, a first magnetic field receiver 3, a second magnetic field receiver 4 and a receiver 5.

[0041] like Figure 2 As shown, the transmitter 1 is connected to the transmitting coil 2 for providing an electrical signal to the transmitting coil 2 .

[0042] Specifically, in this embodiment, the electrical signal provided by the transmitter 1 to the transmitting coil 2 can be an alternating current signal, wherein the waveform of the alternating current signal is any one of a square wave, a sine wave or a triangular wave. In practical applications, the waveform of the alternating current signal is set according to actual needs and is not limited to this embodiment.

[0043] like Figure 2 As shown, the transmitting coil 2 is used to transmit an electromagnetic field to the target object to be measured.

[0044] Specifically, in this embodiment, the transmitting coil 2 is a closed coil, and the shape of the transmitting coil 2 is a circle, or the shape of the transmitting coil 2 is any one of regular polygons such as a rectangle, a regular hexagon, and a regular octagon. As an example, Figure 3 As shown, in another structure of the dual-receiving transient electromagnetic device, the shape of the transmitting coil 2 is rectangular. In practical applications, the shape of the transmitting coil 2 is selected according to needs, and is not limited to this embodiment. Further, after the transmitting coil 2 receives the electrical signal of the transmitter 1, a current is generated in its own coil, thereby generating a primary electromagnetic field. The magnetic induction intensity B of the primary electromagnetic field at different locations is as follows:

[0045]

[0046] Where n represents the number of turns of the transmitting coil 2, μ 0 represents the magnetic permeability of vacuum, C represents the circumference of the transmitting coil 2, I represents the current in the transmitting coil 2, dl represents the line element vector of the transmitting coil 2, and r represents the vector distance from any point in the magnetic field to the line element vector of the transmitting coil 2.

[0047] Specifically, in this embodiment, since transient electromagnetic devices are usually used in geophysical surveys, the target object to be measured in geophysical surveys is usually an underground medium (mineral). Under the influence of the primary electromagnetic field, electric vortices will be generated in the target object to be measured and then a secondary electromagnetic field will be generated. In actual applications, the target object to be measured can be any material that can generate electromagnetic vortices, such as metal or metal dopants, and is not limited to this embodiment.

[0048] like Figure 2 As shown, the first magnetic field receiver 3 is arranged in the area surrounded by the transmitting coil 2, and is used to receive the magnetic field signal and send the first output electrical signal to the receiver 5. Figure 2 As shown, the second magnetic field receiver 4 is arranged outside the area surrounded by the transmitting coil 2 , and is used to receive the magnetic field signal and send a second output electrical signal to the receiver 5 .

[0049] Specifically, in this embodiment, Figure 4 As shown, since the magnetic lines of force are always closed, the directions of the magnetic field in the area surrounded by the transmitting coil 2 and the magnetic field outside the area surrounded by the transmitting coil 2 are opposite. The first magnetic field receiver 3 and the second magnetic field receiver 4 are respectively placed inside and outside the area surrounded by the transmitting coil 2. The purpose is to ensure that the directions of the electromagnetic fields of the first magnetic field receiver 3 and the second magnetic field receiver 4 are always opposite. Since the first magnetic intensity B1 is the electromagnetic field signal received by the first magnetic field receiver 3, and the second magnetic intensity B2 is the electromagnetic field signal received by the second magnetic field receiver 4, by setting the position of the first magnetic field receiver 3 in the transmitting coil 2 and the position of the second magnetic field receiver 4 outside the transmitting coil 2, the vector distance r from the first magnetic field receiver 3 to the line element vector of the transmitting coil 2 is set. 1 and the corresponding vector distance r from the second magnetic field receiver 4 to the line element vector of the transmitting coil 2 2, and substitute the formula of magnetic induction intensity B of the primary electromagnetic field at different locations, the first magnetic intensity B1 and the second magnetic intensity B2 can be made equal in magnitude and opposite in direction. As an example, when calculating the sum of the first magnetic intensity B1 and the second magnetic intensity B2, B1 and B2 are projected in the same direction and then calculated. Under ideal conditions, when the sum of B1 and B2 is equal to zero, it is considered that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction; in practical applications, when the sum of B1 and B2 is within the target range, it can be considered that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction. In practical applications, the specific value of the target range can be set according to actual needs.

[0050] Specifically, in this embodiment, since the magnetic field at the center of the transmitting coil 2 is relatively dense and uniform, the first magnetic field receiver 3 can be set at the center of the transmitting coil 2, so that the first magnetic field receiver 3 has a stronger receiving ability for the secondary electromagnetic field, and the second magnetic field receiver 4 is set at a position outside the transmitting coil 2 according to the magnitude of the first magnetic intensity B1. In practical applications, the specific position of the first magnetic field receiver 3 in the transmitting coil 2 and the specific position of the second magnetic field receiver 4 outside the transmitting coil are set according to actual needs, and are not limited to this embodiment.

[0051] Specifically, in this embodiment, the first magnetic field receiver 3 and the second magnetic field receiver 4 are both magnetic sensors. The purpose of using magnetic sensors is: first, the measurement accuracy of the magnetic sensor is higher, and the receiver 5 can obtain a magnetic field signal with a higher accuracy value; second, the volume of the magnetic sensor is small, which can reduce the mutual inductance between the magnetic sensor and the transmitting coil, so the accuracy of the secondary electromagnetic field signal obtained by the receiver 5 will be improved. In practical applications, the specific types of the first magnetic field receiver 3 and the second magnetic field receiver 4 can be selected as needed, and are not limited to this embodiment.

[0052] like Figure 2 As shown, the receiver 5 is connected to the first magnetic field receiver 3 and the second magnetic field receiver 4 respectively, and performs an addition operation on the first output electrical signal and the second output electrical signal.

[0053] Specifically, in this embodiment, when the electrical signal received on the transmitting coil 2 is at a falling edge, the first magnetic field receiver 3 and the second magnetic field receiver 4 begin to receive the secondary electromagnetic field signal, but the primary electromagnetic field signal will remain on the magnetic field receiver, and the residual primary electromagnetic field signal causes the first magnetic field receiver 3 and the second magnetic field receiver 4 to have a first magnetic intensity and a second magnetic intensity in the primary electromagnetic field, respectively, so the first output electrical signal and the second output electrical signal will both include a primary electromagnetic field signal and a secondary electromagnetic field signal. The dual-receiving transient electromagnetic device of the present invention sets the first magnetic field receiver 3 and the second magnetic field receiver 4 in a primary electromagnetic field of equal magnitude but opposite direction, and the receiver 5 adds the first output electrical signal and the second output electrical signal, and the primary electromagnetic field signal in the electrical signal received by the receiver 5 will be offset, and in the entire periodic change of the electrical signal of the transmitter 1, the weak secondary electromagnetic field early signal will not be covered by the primary electromagnetic field signal, so the dual-receiving transient electromagnetic device of the present invention can detect the precise information of the target object to be measured by detecting the precise secondary electromagnetic field signal.

[0054] Embodiment 2

[0055] like Figure 5 As shown, this embodiment provides a dual-receiving transient electromagnetic method, which is implemented based on the dual-receiving transient electromagnetic device of embodiment 1. The dual-receiving transient electromagnetic method includes the following steps:

[0056] like Figure 2 As shown, the transmitter is turned on, so that the transmitter 1 sends an electrical signal to the transmitting coil 2; the transmitting coil 2 generates a primary electromagnetic field; the target object to be measured generates a secondary electromagnetic field after receiving the primary electromagnetic field; the first magnetic field receiver 3 receives the magnetic field signal in the space and sends a first output electrical signal to the receiver 5; the second magnetic field receiver 4 receives the magnetic field signal in the space and sends a second output electrical signal to the receiver 5; the receiver 5 adds the first output electrical signal and the second output electrical signal.

[0057] Specifically, in this embodiment, in order to better receive the secondary electromagnetic field signal (to improve the strength and quality of the secondary electromagnetic field signal as much as possible), when the target object to be measured is an underground medium, the transmitting coil 2, the first magnetic field receiver 3 and the second magnetic field receiver 4 are all attached to the surface of the earth; when the target object to be measured is an above-ground medium, that is, the target object to be measured is located in the landform on the ground, the transmitting coil 2, the first magnetic field receiver 3 and the second magnetic field receiver 4 are all attached to the surface of the above-ground landform. As an example, when the target object to be measured is an underground medium, such as Figure 6 As shown, when the ground surface is flat, the transmitting coil 2, the first magnetic field receiver 3 and the second magnetic field receiver 4 are located on the same horizontal line; Figure 7As shown, when the ground surface is uneven, the transmitting coil 2, the first magnetic field receiver 3 and the second magnetic field receiver 4 are arranged on different horizontal lines. In practical applications, the locations where the transmitting coil 2, the first magnetic field receiver 3 and the second magnetic field receiver 4 are arranged on the ground surface or the surface of the landform are arranged according to the characteristics of the landform, and are not limited to this embodiment.

[0058] Specifically, in this embodiment, the positions of the first magnetic field receiver 3 and the second magnetic field receiver 4 are adjusted, and the first magnetic intensity B1 and the second magnetic intensity B2 are calculated so that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction, so that after the receiver 5 adds the first output electrical signal and the second output electrical signal, the primary electromagnetic field signal in the electrical signal received by the receiver is offset. The first magnetic intensity B1 is the magnetic induction intensity generated by the primary electromagnetic field in the first magnetic field receiver, and the second magnetic intensity B2 is the magnetic induction intensity generated by the primary electromagnetic field in the second magnetic field receiver. The calculation formulas for the first magnetic intensity B1 and the second magnetic intensity B2 are respectively:

[0059]

[0060] Specifically, in this embodiment, the position of the first magnetic field receiver 3 is adjusted to adjust the vector distance r from the first magnetic field receiver 3 to the line element vector of the transmitting coil 2. 1 , and adjust the position of the second magnetic field receiver 4 to adjust the vector distance r from the second magnetic field receiver 4 to the line element vector of the transmitting coil 2 2 , so that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction. Ideally, the sum of the first magnetic intensity B1 and the second magnetic intensity B2 should be zero, at which time it is considered that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction. In practical applications, if the sum of the first magnetic intensity B1 and the second magnetic intensity B2 is within the target range, it can be considered that the first magnetic intensity B1 and the second magnetic intensity B2 are equal in magnitude and opposite in direction.

[0061] Specifically, in this embodiment, the circumference, number of turns or shape of the transmitting coil is adjusted according to the exploration depth of the target object to be measured. Furthermore, when the exploration depth of the target object to be measured is deep, the magnetic moment required by the transmitting coil 2 is large, and the transmitting coil needs to be adjusted to a coil with a longer circumference, more turns or a simpler shape (limited by the difficulty of processing, when the coil magnetic moment is large, the coil shape needs to be designed to be simpler); when the exploration depth of the target object to be measured is shallow, the magnetic moment required by the transmitting coil 2 is small, and the transmitting coil needs to be adjusted to a coil with a shorter circumference or fewer turns (when the coil magnetic moment is small, the coil shape can be simple or complex). In actual applications, the circumference, number of turns and shape of the transmitting coil are set as needed, not limited to this embodiment.

[0062] In summary, the dual-receiving transient electromagnetic device of the present invention includes a transmitter, a transmitting coil, a first magnetic field receiver, a second magnetic field receiver and a receiver. The present invention places the first magnetic field receiver and the second magnetic field receiver inside and outside the transmitting coil respectively, and adjusts the positions of the first magnetic field receiver and the second magnetic field receiver so that the primary electromagnetic fields on the first magnetic field receiver and the second magnetic field receiver are equal in size and opposite in direction. The receiver performs an addition operation on the received electrical signal, so that the primary electromagnetic field signal in the electrical signal received by the receiver can be offset, and the receiver can obtain an accurate secondary electromagnetic field signal. Therefore, the present invention can realize accurate detection of the secondary electromagnetic field signal to perform accurate geophysical survey. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A dual-receiving transient electromagnetic device, characterized in that: The dual-receiving transient electromagnetic device at least comprises: a transmitter, a transmitting coil, a first magnetic field receiver, a second magnetic field receiver and a receiver; The transmitter is connected to the transmitting coil and is used to provide an electrical signal to the transmitting coil; The transmitting coil is used to transmit an electromagnetic field toward the target object to be measured; The first magnetic field receiver is arranged in the area surrounded by the transmitting coil, and is used to receive the magnetic field signal and send a first output electrical signal to the receiver; The second magnetic field receiver is arranged outside the area surrounded by the transmitting coil, and is used to receive the magnetic field signal and send a second output electrical signal to the receiver; The receiver is connected to the first magnetic field receiver and the second magnetic field receiver respectively, and performs an addition operation on the first output electrical signal and the second output electrical signal.

2. The dual-receiving transient electromagnetic device according to claim 1, characterized in that: The shape of the transmitting coil is a circle, or the shape of the transmitting coil is any one of a regular polygon.

3. The dual-receiving transient electromagnetic device according to claim 1, characterized in that: The first magnetic field receiver and the second magnetic field receiver are both magnetic sensors.

4. The dual-receiving transient electromagnetic device according to claim 1, characterized in that: The first magnetic field receiver is located at the center of the transmitting coil.

5. A dual-receiving transient electromagnetic method, implemented based on the dual-receiving transient electromagnetic device according to any one of claims 1 to 4, characterized in that: The dual-receiving transient electromagnetic method at least includes: turning on the transmitter so that the transmitter sends an electrical signal to the transmitting coil; the transmitting coil generates a primary electromagnetic field; the target object to be measured generates a secondary electromagnetic field after receiving the primary electromagnetic field; the first magnetic field receiver receives the magnetic field signal in the space and sends a first output electrical signal to the receiver; the second magnetic field receiver receives the magnetic field signal in the space and sends a second output electrical signal to the receiver; the receiver performs an addition operation on the first output electrical signal and the second output electrical signal.

6. The dual-receiving transient electromagnetic method according to claim 5, characterized in that: When the target object to be measured is an underground medium, the transmitting coil, the first magnetic field receiver and the second magnetic field receiver are all attached to the ground surface; or when the target object to be measured is an above-ground medium, the transmitting coil, the first magnetic field receiver and the second magnetic field receiver are all attached to the surface of the landform.

7. The dual-receiving transient electromagnetic method according to claim 5, characterized in that: Adjust the positions of the first magnetic field receiver and the second magnetic field receiver, calculate the first magnetic intensity and the second magnetic intensity, so that the first magnetic intensity and the second magnetic intensity are equal in magnitude and opposite in direction, wherein the first magnetic intensity is the magnetic induction intensity generated by the primary electromagnetic field in the first magnetic field receiver, and the second magnetic intensity is the magnetic induction intensity generated by the primary electromagnetic field in the second magnetic field receiver.

8. The dual-receiving transient electromagnetic method according to claim 7, characterized in that: The calculation formulas of the first magnetic intensity and the second magnetic intensity are respectively: Wherein, B1 represents the first magnetic intensity, B2 represents the second magnetic intensity, n represents the number of turns of the transmitting coil, μ0 represents the vacuum magnetic permeability, C represents the circumference of the transmitting coil, I represents the current in the transmitting coil, d1 represents the line element vector of the transmitting coil, r1 represents the vector distance from the first magnetic field receiver to the line element vector of the transmitting coil, and r2 represents the vector distance from the second magnetic field receiver to the line element vector of the transmitting coil.

9. The dual-receiving transient electromagnetic method according to claim 5, characterized in that: According to the exploration depth of the target object to be detected, the circumference, number of turns or shape of the transmitting coil is adjusted.

Images