Massive transient electromagnetic data acquisition method and apparent resistivity calculation method

Abstract

The present application provides a method for acquiring massive transient electromagnetic data and calculating transient electromagnetic apparent resistivity, which relates to the field of geophysical signal acquisition and processing technology, including: traversing all actual measuring points along the measurement path, obtaining the induced electromotive force of each actual measuring point through a large fixed source loop observation device; superimposing the induced electromotive force of each actual measuring point; based on any four actual measuring points of a single measurement, using a bilinear interpolation algorithm to calculate the induced electromotive force of the first interpolation measuring point; based on the principle that the first interpolation direction is adjacent and the second interpolation direction is one point apart, selecting any four first interpolation measuring points, and using a bilinear interpolation algorithm to calculate the induced electromotive force of the second interpolation measuring point; the first interpolation direction is the direction perpendicular to the survey line, and the second interpolation direction is the survey line direction. The present application solves the technical problem of low detection accuracy caused by the small number of measuring points in the prior art, and improves detection efficiency and detection accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of geophysical signal acquisition and processing, and in particular to a method for acquiring massive transient electromagnetic data and calculating transient electromagnetic apparent resistivity. Background Art

[0002] At present, in the exploration technology of groundwater bodies, the transient electromagnetic method is usually used to detect the distribution of groundwater because the content of the aqueous solution directly affects the resistivity.

[0003] The transient electromagnetic method is a method of detecting the resistivity of the medium by emitting a pulse magnetic field underground using an ungrounded return line or a grounded line source, and observing the secondary induced eddy current field caused in the underground medium using a coil or a grounding electrode during the interval of the pulse magnetic field.

[0004] Due to the constraints of the complex geological environment, data can only be collected at fixed measuring points. Due to the limited number of measuring points, the collected data is greatly affected by interference noise and the detection accuracy is low. Increasing the number of measuring points will increase the detection time, reduce work efficiency, and cannot meet the requirements of rapid detection. Summary of the invention

[0005] In view of this, the present application proposes a method for acquiring transient electromagnetic data and calculating transient electromagnetic apparent resistivity to solve the technical problem of low detection accuracy caused by a small number of measuring points in the prior art.

[0006] On the one hand, an embodiment of the present application provides a method for acquiring massive transient electromagnetic data, comprising:

[0007] Traverse all actual measuring points along the measuring path, and obtain the induced electromotive force of each actual measuring point through the large fixed source loop observation device;

[0008] Perform superposition processing on the induced electromotive force of each actual measuring point;

[0009] Based on the four actual measuring points of any single measurement, the bilinear interpolation algorithm is used to calculate the induced electromotive force of the first interpolation measuring point;

[0010] Based on the principle that the first interpolation direction is adjacent and the second interpolation direction is one point apart, any four first interpolation measuring points are selected, and the induced electromotive force of the second interpolation measuring points is calculated using a bilinear interpolation algorithm; the first interpolation direction is a direction perpendicular to the measuring line, and the second interpolation direction is the measuring line direction.

[0011] Furthermore, the large fixed source loop observation device includes a transmitting coil and four receiving coils. During each measurement, the four receiving coils are arranged at four adjacent actual measuring points in the upper, lower, left and right directions, and the transmitting coil is arranged outside the area formed by the four receiving coils.

[0012] Furthermore, before traversing all actual measurement points along the measurement path, the method includes:

[0013] Determine the direction, length and number of survey lines in the survey area, where the direction of the survey lines is perpendicular to the possible geological structure direction and all survey lines can cover the entire survey area;

[0014] Determine the distance between adjacent measuring points on the measuring line, thereby determining the actual measuring point position; wherein the actual measuring point distance is equal to the side length of the receiving coil loop or half of the side length of the loop.

[0015] Furthermore, all actual measuring points are traversed along the measuring path, and the induced electromotive force of each actual measuring point is obtained through the large fixed source loop observation device, including:

[0016] Assume that there are N survey lines in the whole survey area, and each survey line has M actual survey points. The nth actual survey point on the mth survey line is S. mn ;

[0017] The actual measurement points for the first measurement are: S 11 , S 12 , S 21 and S 22 ; The observation device moves as a whole along the positive direction of the measuring line. During the second measurement, the actual measuring points are: S 12 , S 13 , S 22 and S 23 ; During the M-1th measurement, the actual measurement points are: S 1，M-1 , S 1M , S 2，M-1 and S 2M ; Then move as a whole in the direction perpendicular to the measuring line. During the Mth measurement, the actual measuring points are: S 2，M-1 , S 2M , S 3，M-1 and S 3M ; The observation device moves as a whole in the opposite direction of the measurement line. During the M+1th measurement, the actual measurement points are: S 2，M-2 , S 2，M-1 , S 3，M-2 and S 3，M-1 ; Traverse all actual measuring points along the loop path until the last measurement. The actual measuring points are: S N-1，M-1 , S N-1，M , S N，M-1 and S N，M ;

[0018] At each actual measuring point, the induced electromotive force of multiple time periods is obtained through a large fixed source loop observation device; and the measurement is repeated along the loop path.

[0019] Furthermore, the induced electromotive force of each actual measuring point is superimposed, including:

[0020] When the number of measurements I at an actual measuring point is greater than 1, the induced electromotive force U at the actual measuring point is:

[0021]

[0022] Where: U i is the induced electromotive force obtained by the i-th measurement, r i is the correlation value corresponding to the induced electromotive force, r i ≥r min , r min is the correlation threshold, when I=1, r1=1.

[0023] Furthermore, when the four adjacent actual measurement points are S 11 , S 12 , S 21 and S 22 When the induced electromotive force of the first interpolation measuring point is calculated based on the four actual measuring points of any single measurement, a bilinear interpolation algorithm is used; comprising:

[0024] S 11 , S 12 , S 21 and S 22 The coordinate values ​​of the four measuring points are: (x 11 ,y 11 )、(x 12 ,y 12 )、(x 21 ,y 21 ) and (x 22 ,y 22 ), the induced electromotive force after superposition is U 11 , U 12 , U 21 and U 22 ;

[0025] The coordinates of the first interpolation point P are (x, y). First, perform single linear interpolation in the first interpolation direction to obtain the induced electromotive force of O1 and O2. and

[0026]

[0027]

[0028] Among them, the coordinates of O1 are: (x 11 , y), the coordinates of O2 are: (x 12 , y);

[0029] Perform single linear interpolation on O1 and O2 in the second interpolation direction to obtain the induced electromotive force at point P:

[0030]

[0031] On the other hand, an embodiment of the present application provides a method for calculating apparent resistivity, including:

[0032] Obtaining the induced electromotive force of all measuring points in the measurement area, wherein the measuring point is any one of the actual measuring point, the first interpolation measuring point and the second interpolation measuring point;

[0033] Based on the induced electromotive force at the measuring point, calculate the apparent resistivity of the measuring point;

[0034] The apparent resistivity of all measuring points is inverted in one dimension and imaged in three dimensions to generate a stereoscopic apparent resistivity distribution map of the measuring area.

[0035] On the other hand, an embodiment of the present application provides an apparent resistivity calculation device, comprising:

[0036] An acquisition unit, used for acquiring the induced electromotive force of all measuring points in the measurement area, wherein the measuring point is any one of the actual measuring point, the first interpolation measuring point and the second interpolation measuring point;

[0037] A calculation unit, used for calculating the apparent resistivity of the measuring point based on the induced electromotive force of the measuring point;

[0038] The inversion unit is used to perform one-dimensional inversion and three-dimensional imaging of the apparent resistivity of all measuring points to generate a stereoscopic apparent resistivity distribution map of the measuring area.

[0039] On the other hand, an embodiment of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the apparent resistivity calculation method of the embodiment of the present application when executing the computer program.

[0040] On the other hand, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the apparent resistivity calculation method of the embodiment of the present application is implemented.

[0041] Compared with the prior art, the advantages of this application are:

[0042] 1. This application adopts the linear interpolation method, which can obtain data from more measuring points without increasing the observation time, greatly improving work efficiency and meeting the requirements of rapid detection;

[0043] 2. This application aims at suppressing the noise interference on the collected signal data by obtaining high-density measurement point data, thereby obtaining data with a higher signal-to-noise ratio and improving detection accuracy;

[0044] 3. This application calculates the apparent resistivity based on high-density transient electromagnetic data, and then performs refined three-dimensional mapping of the underground space data, which can effectively realize the three-dimensional display of groundwater bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 A flowchart of a method for acquiring massive transient electromagnetic data provided in an embodiment of the present application;

[0047] Figure 2 A schematic diagram of the distribution of measurement lines and measurement points provided in an embodiment of the present application;

[0048] Figure 3 A schematic diagram of a large fixed source loop observation device provided in an embodiment of the present application;

[0049] Figure 4 A flow chart of a method for calculating apparent resistivity provided in an embodiment of the present application;

[0050] Figure 5 A transient electromagnetic three-dimensional apparent resistivity slice diagram provided in an embodiment of the present application;

[0051] Figure 6 A flow chart of an apparent resistivity calculation device provided in an embodiment of the present application;

[0052] Figure 7 A schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0054] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0055] First, the design concept of the embodiments of the present application is briefly introduced.

[0056] When using transient electromagnetic method to detect the distribution of groundwater, due to the limitation of complex geological environment, data can only be collected at fixed measuring points. Due to the limitation of the number of measuring points, the collected data is greatly affected by interference noise and the detection accuracy is low. Increasing the number of measuring points will increase the detection time, reduce work efficiency, and fail to meet the requirements of rapid detection.

[0057] In response to the above problems, this application proposes a method for acquiring massive transient electromagnetic data. First, the measuring points along the survey line are detected point by point, and repeated observations are performed after a certain distance. On this basis, bilinear interpolation is performed between the four actual measuring points of any single measurement to obtain the transient electromagnetic data of the first interpolation measuring point. Then, based on the principle that the first interpolation direction is adjacent and the second interpolation direction is separated by one point, any four first interpolation measuring points are selected, and the induced electromotive force of the second interpolation measuring point is obtained by using a bilinear interpolation algorithm; wherein the first interpolation direction is the direction perpendicular to the survey line, and the second interpolation direction is the survey line direction. The number of measuring points is increased by the interpolation method, thereby obtaining massive transient electromagnetic data.

[0058] Compared with the traditional ground transient electromagnetic detection of fixed points arranged according to the design, the massive transient electromagnetic data acquisition method of the present application can detect the geological structure below the ground more efficiently and quickly and obtain massive data.

[0059] In addition, the present application also proposes a method for calculating apparent resistivity, which uses massive transient electromagnetic data to calculate apparent resistivity, performs one-dimensional inversion and three-dimensional imaging on all apparent resistivity and depth curves, obtains the stereoscopic apparent resistivity distribution of each survey area, and realizes three-dimensional display of the groundwater storage status by transient electromagnetic.

[0060] After introducing the application scenarios and design concepts of the embodiments of the present application, the technical solutions provided by the embodiments of the present application are described below.

[0061] Embodiment 1:

[0062] like Figure 1 As shown, the embodiment of the present application proposes a method for acquiring massive transient electromagnetic data, including:

[0063] Step 101: designing multiple survey lines and actual measurement points according to the survey area;

[0064] According to the overall geological task plan, design as many survey lines as possible if geological conditions permit;

[0065] The survey line direction should be perpendicular to the possible geological structure direction, and each survey line should be as parallel as possible; and the survey line should be long enough to cover the entire survey area as much as possible, so as to control the structural morphology and geological targets.

[0066] Determine the distance between adjacent measuring points in the measuring line direction, and then determine the actual measuring points; the distribution of the actual measuring points is as follows: Figure 2 As shown. The actual measurement point distance is generally equal to the side length of the receiving coil loop or half of the side length of the loop;

[0067] Step 102: traverse all actual measuring points along the measuring path, and obtain the induced electromotive force of each actual measuring point through a large fixed source loop observation device;

[0068] like Figure 3 As shown, the large fixed source loop observation device includes a transmitting coil T and four receiving coils R1, R2, R3 and R4. During each measurement, the four receiving coils are arranged at four adjacent actual measuring points in the upper, lower, left and right directions, and the transmitting coil is arranged outside the area formed by the four receiving coils.

[0069] During the measurement, when the transmitting coil and the receiving coil are laid out, the transmitting coil transmits a signal, and four receiving coils simultaneously receive the signal reflected from the underground, thereby obtaining the induced electromotive force of four actual measuring points. The induced electromotive force of each actual measuring point includes multiple induced electromotive force values ​​collected at different times, and each induced electromotive force value corresponds to an underground depth value.

[0070] Induced electromotive force is the phenomenon of electromagnetic induction. Since there is induced current in a closed circuit, there must be electromotive force in this circuit. The electromotive force generated in the phenomenon of electromagnetic induction is called induced electromotive force.

[0071] like Figure 2 As shown in the figure, the nth actual measuring point on the mth measuring line is denoted as S mn There are N measuring lines in total, and each measuring line has M actual measuring points; then the actual measuring points for the first measurement are: S 11 , S 12 , S 21 and S 22 , the observation device moves as a whole along the positive direction of the measuring line. During the second measurement, the actual measuring points are: S 12 , S 13 , S 22 and S 23 , during the M-1th measurement, the actual measurement points are: S 1，M-1 , S 1M , S 2，M-1 and S 2M; Then move as a whole in the direction perpendicular to the measuring line. During the Mth measurement, the actual measuring points are: S 2，M-1 , S 2M , S 3，M-1 and S 3M ; Move as a whole in the opposite direction of the measuring line. When measuring for the M+1th time, the actual measuring points are: S 2，M-2 , S 2，M-1 , S 3，M-2 and S 3，M-1 , and thus traverse all actual measurement points along the loop path until the last measurement. The actual measurement points are: S N-1，M-1 , S N-1，M , S N，M-1 and S N，M .

[0072] At each actual measuring point, the induced electromotive force of multiple time periods is obtained through a large fixed source loop observation device; and the measurement is repeated along the loop path.

[0073] Step 103: performing superposition processing on the induced electromotive force of each actual measuring point;

[0074] According to the measurement process of step 102, it can be found that multiple measurements are performed at each actual measurement point, so the number of induced electromotive forces measured is more than one, and superposition processing is required:

[0075]

[0076] Where: U i is the induced electromotive force obtained by the i-th measurement, r i is the correlation value corresponding to the induced electromotive force, r i ≥r min , r min is the correlation threshold, U is the induced electromotive force of the measuring point, and in particular, if the actual measuring point is only measured once, that is, I=1, then r1=1.

[0077] Step 104: Based on four actual measurement points of any single measurement, a bilinear interpolation algorithm is used to calculate the induced electromotive force of the first interpolation measurement point;

[0078] For the establishment of the coordinate system of the measurement area, as long as the measurement line direction is the X axis, the origin can be selected at the first actual measurement point S 11 , then the positive direction of the X-axis is the measuring direction of the survey line, and there is no limitation on this.

[0079] Take four adjacent measuring points S 11 , S 12 , S 21 and S 22 For example: S 11 and S12 On the same measuring line, S 21 and S 22 At the same position of the adjacent survey line, it corresponds to the adjacent survey line; S 11 , S 12 , S 21 and S 22 The coordinate values ​​of the four measuring points are: (x 11 ,y 11 )、(x 12 ,y 12 )、(x 21 ,y 21 ) and (x 22 ,y 22 ), the induced electromotive force after superposition is U 11 , U 12 , U 21 and U 22 .x 11 =x 21 , x 12 =x 22 ;y 11 =y 12 ,y 21 =y 22 ;

[0080] If the coordinates of the first interpolation point P are (x, y), perform single linear interpolation in the y direction according to formulas (2) and (3) to obtain the induced electromotive force of O1 and O2:

[0081]

[0082]

[0083] Among them, the coordinates of O1 are: (x 11 , y), the coordinates of O2 are: (x 12 , y);

[0084] Then, according to formula (4), single linear interpolation in the x direction is performed to obtain the induced electromotive force U at point P: P :

[0085]

[0086] Step 105: Based on the principle that the first interpolation direction is adjacent and the second interpolation direction is separated by one point, any four first interpolation measurement points are selected, and the induced electromotive force of the second interpolation measurement points is calculated using a bilinear interpolation algorithm;

[0087] The first interpolation direction is perpendicular to the survey line, and the second interpolation direction is the survey line direction. Figure 2 shown.

[0088] Embodiment 2:

[0089] like Figure 4 As shown, based on the method for acquiring massive transient electromagnetic data in the above embodiment, the embodiment of the present application proposes a method for calculating apparent resistivity, including:

[0090] Step 201: Obtain the induced electromotive force of each measuring point; the measuring points include: an actual measuring point, a first interpolation measuring point and a second interpolation measuring point.

[0091] Step 202: Calculate the apparent resistivity of each measuring point using the induced electromotive force of the measuring point. The calculation formula is as follows:

[0092]

[0093] Where: ρ is the apparent resistivity, which includes multiple apparent resistivities corresponding to underground depth values; μ0 is the magnetic permeability, a is the radius of the transmitting coil loop, t is the delay time after the power supply current is turned off; U is the induced electromotive force at the measuring point.

[0094] Step 203: Perform one-dimensional inversion and three-dimensional imaging on the apparent resistivity of all measuring points to obtain a stereoscopic apparent resistivity distribution map of the measuring area;

[0095] The specific process is as follows:

[0096] Construct the damped least squares inversion objective function:

[0097] (G+αI)Δm=d (6)

[0098] Among them, α is the damping coefficient, I is the unit matrix, Δm is the model correction, and G is the Jacobian matrix:

[0099]

[0100]

[0101] f is the objective function, x i is the parameter to be solved; K is the product of the total number of all measuring points and the number of values ​​contained in the apparent resistivity;

[0102] d is a matrix composed of the difference between each apparent resistivity value and the theoretical value at each measuring point:

[0103]

[0104] Formula (6) is solved iteratively until the iteration termination condition is met (for example, the difference between two consecutive iterations is less than 10 -6 ), terminate the iteration and get the optimal solution;

[0105] The inverted apparent resistivity-depth data is sliced ​​to perform three-dimensional imaging, such as Figure 5 shown.

[0106] Embodiment 3:

[0107] Based on the above embodiments, the present application provides an apparent resistivity calculation device, see Figure 6 As shown, the apparent resistivity calculation device 300 provided in the embodiment of the present application at least includes:

[0108] The acquisition unit 301 is used to acquire the induced electromotive force of each measuring point; the measuring points include: an actual measuring point, a first interpolation measuring point and a second interpolation measuring point.

[0109] Calculation unit 302: Calculate the apparent resistivity of each measuring point using the induced electromotive force of the measuring point. The calculation formula is as follows:

[0110]

[0111] Where: ρ is the apparent resistivity, which contains multiple apparent resistivity values ​​corresponding to the underground depth values; μ0 is the magnetic permeability, a is the radius of the transmitting coil loop, t is the delay time after the power supply current is turned off; U is the induced electromotive force of the measuring point.

[0112] Inversion unit 303: used to perform one-dimensional inversion and three-dimensional imaging on the apparent resistivity of all measuring points to obtain a three-dimensional apparent resistivity distribution map of the measuring area; the specific process is as follows:

[0113] Construct the damped least squares inversion objective function:

[0114] (G+αI)Δm=d (6)

[0115] Among them, α is the damping coefficient, I is the unit matrix, Δm is the model correction, and G is the Jacobian matrix:

[0116]

[0117]

[0118] f is the objective function, x i is the parameter to be solved; K is the product of the total number of all measuring points and the number of values ​​contained in the apparent resistivity;

[0119] d is a matrix composed of the difference between each apparent resistivity value and the theoretical value at each measuring point:

[0120]

[0121] Formula (6) is solved iteratively until the iteration termination condition is met (for example, the difference between two consecutive iterations is less than 10 -6), terminate the iteration and get the optimal solution.

[0122] Embodiment 4:

[0123] Based on the above embodiments, the present application also provides an electronic device, referring to Figure 7 As shown, the electronic device 400 provided in the embodiment of the present application includes at least: a processor 401, a memory 402, and a computer program stored in the memory 402 and executable on the processor 401. When the processor 401 executes the computer program, the apparent resistivity calculation method provided in the embodiment of the present application is implemented.

[0124] The electronic device 400 provided in the embodiment of the present application may further include a bus 403 connecting different components (including the processor 401 and the memory 402). The bus 403 represents one or more of several types of bus structures, including a memory bus, a peripheral bus, a local bus, and the like.

[0125] The memory 402 may include a readable medium in the form of a volatile memory, such as a random access memory (RAM) 4021 and / or a cache memory 4022 , and may further include a read-only memory (ROM) 4023 .

[0126] The memory 402 may also include a program tool 4024 having a set (at least one) of program modules 4025, the program modules 4025 including but not limited to: an operating subsystem, one or more applications, other program modules, and program data, each of which or some combination may include the implementation of a network environment.

[0127] The electronic device 400 may also communicate with one or more external devices 404 (e.g., keyboards, remote controls, etc.), and may also communicate with one or more devices that enable a user to interact with the electronic device 400 (e.g., mobile phones, computers, etc.), and / or communicate with any device that enables the electronic device 400 to communicate with one or more other electronic devices 400 (e.g., routers, modems, etc.). Such communication may be performed through an input / output (I / O) interface 405. Furthermore, the electronic device 400 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 406. Figure 7 As shown, the network adapter 406 communicates with other modules of the electronic device 400 via the bus 403. It should be understood that although Figure 7Not shown, other hardware and / or software modules may be used in conjunction with the electronic device 400, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, disk arrays (Redundant Arrays of Independent Disks, RAID) subsystems, tape drives, and data backup storage subsystems.

[0128] It should be noted that Figure 7 The electronic device 400 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0129] Embodiment 5:

[0130] The embodiment of the present application also provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the apparent resistivity calculation method provided in the embodiment of the present application is implemented.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for acquiring massive transient electromagnetic data, characterized in that: include: Traverse all actual measuring points along the measuring path, and obtain the induced electromotive force of each actual measuring point through the large fixed source loop observation device; Superposition processing is performed on the induced electromotive force of each actual measuring point; Based on the four actual measuring points of any single measurement, the bilinear interpolation algorithm is used to calculate the induced electromotive force of the first interpolation measuring point; Based on the principle that the first interpolation direction is adjacent and the second interpolation direction is separated by one point, any four first interpolation measurement points are selected, and the induced electromotive force of the second interpolation measurement points is calculated using a bilinear interpolation algorithm; the first interpolation direction is a direction perpendicular to the measurement line, and the second interpolation direction is the measurement line direction; Among them, all actual measuring points are traversed along the measuring path, and the induced electromotive force of each actual measuring point is obtained through the large fixed source loop observation device, including: Assume that there are N survey lines in the whole survey area, and each survey line has M actual survey points. The nth actual survey point on the mth survey line is S. mn ; The actual measurement points for the first measurement are: S 11 , S 12 , S 21 and S 22 ; The observation device moves as a whole along the positive direction of the measuring line. During the second measurement, the actual measuring points are: S 12 , S 13 , S 22 and S 23 ; During the M-1th measurement, the actual measurement points are: S 1,M-1 , S 1M , S 2,M-1 and S 2N ; Then move as a whole in the direction perpendicular to the measuring line. During the Mth measurement, the actual measuring points are: S 2,M-1 , S 2M , S 3,M-1 and S 3M ; The observation device moves as a whole in the opposite direction of the measurement line. During the M+1th measurement, the actual measurement points are: S 2,M-2 , S 2,M-1 , S 3,M-2 and S 3,M-1 ; Traverse all actual measuring points along the loop path until the last measurement. The actual measuring points are: S N-1,M-1 , S N-1,M , S N,M-1 and S N,M ; At each actual measuring point, the induced electromotive force of multiple time periods is obtained through a large fixed source loop observation device; and the measurement is repeated along the loop path; Among them, the induced electromotive force of each actual measuring point is superimposed, including: When the number of measurements I at an actual measuring point is greater than 1, the induced electromotive force U at the actual measuring point is: Where: U i is the induced electromotive force obtained by the i-th measurement, r i is the correlation value corresponding to the induced electromotive force, r i ≥r min , r min is the correlation threshold, when I=1, r1=1.

2. The method for acquiring massive transient electromagnetic data according to claim 1, characterized in that: The large fixed source loop observation device includes a transmitting coil and four receiving coils. During each measurement, the four receiving coils are arranged at four adjacent actual measuring points, and the transmitting coil is arranged outside the area formed by the four receiving coils.

3. The method for acquiring massive transient electromagnetic data according to claim 2, characterized in that: Before traversing all actual measurement points along the measurement path, the method includes: Determine the direction, length and number of survey lines in the survey area, where the direction of the survey lines is perpendicular to the possible geological structure direction and all survey lines can cover the entire survey area; Determine the distance between adjacent measuring points on the measuring line, thereby determining the actual measuring point position; wherein the actual measuring point distance is equal to the side length of the receiving coil loop or half of the side length of the loop.

4. The method for acquiring massive transient electromagnetic data according to claim 1, characterized in that: When the four adjacent actual measuring points are S 11 , S 12 , S 21 and S 22 When the four actual measuring points based on any single measurement are used, a bilinear interpolation algorithm is used to calculate the induced electromotive force of the first interpolation measuring point; include: S 11 , S 12 , S 21 and S 22 The coordinate values ​​of the four measuring points are: (x 11 ,y 11 )、(x 12 ,y 12 )、(x 21 ,y 21 ) and (x 22 ,y 22 ), the induced electromotive force after superposition is U 11 , U 12 , U 21 and U 22 ; The coordinates of the first interpolation point P are (x, y). First, perform single linear interpolation in the first interpolation direction to obtain the induced electromotive force of O1 and O2. and Among them, the coordinates of O1 are: (x 11 , y), the coordinates of O2 are: (x 12 , y); Perform single linear interpolation on O1 and O2 in the second interpolation direction to obtain the induced electromotive force at point P:

5. A method for calculating apparent resistivity based on the method for acquiring massive transient electromagnetic data according to any one of claims 1 to 4, characterized in that: include: Obtaining the induced electromotive force of all measuring points in the measurement area, wherein the measuring point is any one of the actual measuring point, the first interpolation measuring point and the second interpolation measuring point; Based on the induced electromotive force at the measuring point, calculate the apparent resistivity of the measuring point; The apparent resistivity of all measuring points is inverted in one dimension and imaged in three dimensions to generate a stereoscopic apparent resistivity distribution map of the measuring area.

6. An apparent resistivity calculation device based on the method for acquiring massive transient electromagnetic data according to any one of claims 1 to 4, characterized in that: include: An acquisition unit, used for acquiring the induced electromotive force of all measuring points in the measurement area, wherein the measuring point is any one of the actual measuring point, the first interpolation measuring point and the second interpolation measuring point; A calculation unit, used for calculating the apparent resistivity of the measuring point based on the induced electromotive force of the measuring point; The inversion unit is used to perform one-dimensional inversion and three-dimensional imaging of the apparent resistivity of all measuring points to generate a stereoscopic apparent resistivity distribution map of the measuring area.

7. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the apparent resistivity calculation method according to claim 5 when executing the computer program.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the apparent resistivity calculation method according to claim 5 is implemented.

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