A method and system for correcting system deviation between transient electromagnetic data measurement lines

Abstract

The present application discloses a method and system for correcting the systematic deviation between transient electromagnetic data survey lines, which relates to the field of electromagnetic detection technology. The method includes: obtaining transient electromagnetic response data of each survey line in the target working area; the survey line includes multiple survey points; the survey points on different survey lines at the same time constitute a time channel; the transient electromagnetic response data includes a number of transient electromagnetic response values; for each time channel, according to the transient electromagnetic response data, the correction coefficients of different survey lines on the time channel are calculated; based on the correction coefficients, the transient electromagnetic response values ​​on the time channel are corrected. The present application uses the correction coefficients to correct the transient electromagnetic responses of different survey lines, eliminates the systematic deviation of transient electromagnetic responses between different survey lines, solves the problem of inconsistent transient electromagnetic responses between different survey lines, and provides reliable transient electromagnetic data for transient electromagnetic response analysis.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic detection technology, and in particular to a method and system for correcting system deviations between transient electromagnetic data measurement lines. Background Art

[0002] Transient Electromagnetic Method (TEM) is a geophysical method for detecting underground resistivity distribution. It is widely used in mineral exploration, environmental monitoring and engineering investigation because of its good resolution and detection capabilities for underground structures of different scales and depths. In actual transient electromagnetic detection, in order to facilitate subsequent data processing and interpretation, several survey lines are generally laid out in the work area, and measurements are carried out on a survey line basis. Since a work area often has multiple survey lines, it generally takes a long time to complete the measurement of all survey lines in the entire work area. Therefore, transient electromagnetic measurements of different survey lines are often completed at different times or on different dates.

[0003] Due to different working conditions at different times, when transient electromagnetic measurements are carried out at different times, factors such as the transmitting current, the impedance characteristics of the transmitting device, and the shallow geoelectric conditions will be different, which will lead to significant systematic deviations in the data on different transient electromagnetic survey lines. When systematic deviations occur, the response amplitudes of some survey lines will be weaker or stronger than the adjacent survey lines as a whole, with significant inconsistencies. This systematic deviation will cause the same geological structure to show inconsistent responses in the measurements of different survey lines, and ultimately manifest as strips or discontinuities along the survey line direction on the electromagnetic response contour map, making it difficult to accurately interpret the underground structure. At the same time, it will affect the subsequent underground structure inversion and interpretation process, resulting in deviations in the reconstruction of the underground electrical structure model, reducing the reliability and accuracy of the interpretation results. Summary of the invention

[0004] The purpose of this application is to provide a method and system for correcting the systematic deviation between transient electromagnetic data survey lines, which can provide reliable transient electromagnetic data for transient electromagnetic response analysis and subsequent quantitative interpretation.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for correcting system deviations between transient electromagnetic data measurement lines, comprising:

[0007] The transient electromagnetic response data of each measuring line in the target working area is obtained; the measuring line includes a plurality of measuring points; the measuring points on different measuring lines at the same time constitute a time track; the transient electromagnetic response data includes a plurality of transient electromagnetic response values.

[0008] For each of the time channels, correction coefficients of different measurement lines on the time channel are calculated according to the transient electromagnetic response data.

[0009] Based on the correction coefficient, the transient electromagnetic response value on the time channel is corrected.

[0010] In a second aspect, the present application provides a system for correcting system deviations between transient electromagnetic data measurement lines, comprising:

[0011] The data acquisition module is used to acquire transient electromagnetic response data of each measuring line in the target working area; the measuring line includes multiple measuring points; the measuring points on different measuring lines at the same time constitute a time channel; the transient electromagnetic response data includes a plurality of transient electromagnetic response values.

[0012] The calculation module is used to calculate the correction coefficients of different measurement lines on each time channel according to the transient electromagnetic response data.

[0013] The correction module is used to correct the transient electromagnetic response value on the time channel based on the correction coefficient.

[0014] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0015] The present application provides a method for correcting the systematic deviation between survey lines of transient electromagnetic data, including: obtaining transient electromagnetic response data of each survey line in the target working area; the survey line includes multiple survey points; the survey points on different survey lines at the same time constitute a time channel; the transient electromagnetic response data includes a number of transient electromagnetic response values; for each time channel, according to the transient electromagnetic response data, the correction coefficients of different survey lines on the time channel are calculated; based on the correction coefficients, the transient electromagnetic response values ​​on the time channel are corrected. The present application is based on the transient electromagnetic raw data, calculates the correction coefficient of the systematic deviation between survey lines through a specific formula, uses the calculated correction coefficient to correct the data of a single time channel, and finally obtains the correction coefficients of all time channels and different survey lines, realizes the correction between survey lines of all transient electromagnetic data, improves the consistency of data between different survey lines, and eliminates the systematic deviation between survey lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1A flowchart of a method for correcting system deviations between transient electromagnetic data measurement lines provided in one embodiment of the present application is provided.

[0018] Figure 2 A schematic diagram of an underground buried abnormal body provided in one embodiment of the present application.

[0019] Figure 3 A plane contour map of transient electromagnetic response of a fixed source loop provided in one embodiment of the present application.

[0020] Figure 4 A correction coefficient for different measurement lines provided in one embodiment of the present application.

[0021] Figure 5 A corrected transient electromagnetic response plane contour map provided in an embodiment of the present application.

[0022] Figure 6 A schematic diagram of the structure of a system for correcting system deviations between transient electromagnetic data measurement lines provided in one embodiment of the present application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] Transient Electromagnetic Method (TEM) is a geophysical method for detecting underground resistivity distribution. Its basic principle is to use the inductive response of transient electromagnetic fields to obtain resistivity information of underground media. Specifically, the transient electromagnetic method places an ungrounded transmitting coil or grounded wire on the ground, feeds the transmitting current into the wire through the transmitting device, and generates a transient electromagnetic pulse, and then measures the induced electromagnetic field response on the ground to infer the underground electrical structure. When the transmitting coil excites the electromagnetic pulse, the underground conductor will induce a current and generate a transient electromagnetic response on the ground. The receiving coil records the transient electromagnetic response at different times, which is called the transient electromagnetic response of different "time channels". These responses are reconstructed through signal processing and inversion algorithms to reconstruct the resistivity structure of the underground medium. Transient electromagnetic method is widely used in mineral exploration, environmental monitoring and engineering investigation because of its good resolution and detection capabilities for underground structures of different scales and depths.

[0025] The purpose of this application is to provide a method and system for correcting the systematic deviation between transient electromagnetic data survey lines, which can provide reliable transient electromagnetic data for transient electromagnetic response analysis and subsequent quantitative interpretation.

[0026] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] Embodiment 1

[0028] like Figure 1 As shown, this embodiment provides a method for correcting system deviation between transient electromagnetic data measurement lines, including:

[0029] Step 101: Acquire transient electromagnetic response data of each measuring line in the target working area; the measuring line includes multiple measuring points; the measuring points on different measuring lines at the same time constitute a time track; the transient electromagnetic response data includes a plurality of transient electromagnetic response values.

[0030] Step 102: For each of the time channels, calculate the correction coefficients of different measurement lines on the time channel according to the transient electromagnetic response data.

[0031] Step 103: Based on the correction coefficient, correct the transient electromagnetic response value on the time channel.

[0032] When executing step 101, the specific steps may be as follows:

[0033] Prepare the transient electromagnetic response data M = [L1, L2, ..., L m ], where L i =[S i1 , S i2 , ..., S in ] is the first i The transient electromagnetic response matrix of the measurement line, S ij =[ d ij1 , d ij2 , ..., d ijp ] is the first i Line j The transient electromagnetic response vector of each measuring point is d ijk For the i Line j The corresponding measuring point k The transient electromagnetic response value of the time channel, m , n , p They are the number of measuring lines, measuring points and time channels respectively.

[0034] When executing step 102, the specific steps may be as follows:

[0035] According to the formula , calculate the correction coefficients for different measurement lines on the first time channel.

[0036] According to the formula , calculate the correction coefficients for different survey lines on the non-first time channel.

[0037] In the formula, W is the length of 2 q +1 weighted vector, starting with - q , the end mark is q , subscript i For the i Lines, c i1 is the correction coefficient for different measurement lines on the first time channel, c ik is the correction coefficient for different measurement lines on the non-first time channel, m is the number of measurement lines, n is the number of measuring points, subscript j For the j measurement points; subscript k Representative k A time road, For the i + l Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point, For the i + l Line j The corresponding measuring point k The transient electromagnetic response value of the time channel, l is the sequence number of the weight vector.

[0038] When executing step 103, the specific steps may be as follows:

[0039] Based on the correction coefficients of different measuring lines on the first time channel, the transient electromagnetic response value on the first time channel is corrected.

[0040] Based on the correction coefficients of different survey lines on the non-first time channel, the transient electromagnetic response values ​​on the non-first time channel are corrected.

[0041] Specifically, based on the correction coefficients of different measurement lines on the first time channel, the correction formula for correcting the transient electromagnetic response value on the first time channel is:

[0042] .

[0043] In the formula, ci1 is the correction coefficient of different measurement lines on the first time channel, with superscript r represents the corrected transient electromagnetic response, d ij1 For the i Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point.

[0044] Specifically, based on the correction coefficients of different measurement lines on the non-first time channel, the correction formula for correcting the transient electromagnetic response value on the non-first time channel is:

[0045] .

[0046] In the formula, c ik is the correction coefficient of different measurement lines on the non-first time channel, with superscript r represents the corrected transient electromagnetic response, d ijk For the i Line j The corresponding measuring point k The transient electromagnetic response value of a time channel.

[0047] The present application is further described in detail below in conjunction with a specific embodiment, as follows:

[0048] S1. For abnormal bodies buried underground (such as Figure 2 ), the background resistivity of the earth is 100Ω·m, the geometric size of the anomaly is 100m×100m×30m, the center is located at (-150m, -150m, -100m), the resistivity is 10Ω·m, and a transmitting loop with a side length of 600m×600m is used. The transmitting current is 18 amperes and the falling edge is 10μs. According to the fixed source loop measurement method, the measurement is completed with a point spacing and line spacing of 25 meters. Under the condition of a 10% system deviation between the same measuring lines, the t = 0.5ms response plane contour map (such as Figure 3 ), it can be seen that the response contour map has obvious strips along the survey line direction.

[0049] S2, adoption q = 1, the weighted vector W = [0.25, 0.5, 0.25], calculate t =0.5ms, the correction coefficients for different measurement lines are calculated as follows: Figure 4 shown.

[0050] S3, yes t = 0.5ms, all transient electromagnetic responses are corrected using the correction coefficient, and the correction formula is:

[0051] .

[0052] Among them, the superscript r represents the corrected transient electromagnetic response, t = 0.5ms response plane contour map Figure 5 As shown in the figure, it can be seen that the systematic deviation of the data between the measurement lines has been significantly eliminated after correction.

[0053] S4. Calculate the correction coefficients of different measurement lines on the remaining time channels using the following formula:

[0054] .

[0055] Among them, the weight vector W = [0.25, 0.5, 0.25], subscript i Representative i Line, subscript j Representative j Measurement points, subscript k Representative k A time road.

[0056] S5. For all transient electromagnetic responses on the remaining time channels, correction coefficients are used for correction. The correction formula is:

[0057] .

[0058] Corrected transient electromagnetic response matrix .

[0059] Embodiment 2

[0060] like Figure 6 As shown, this embodiment provides a system for correcting system deviations between transient electromagnetic data measurement lines, including:

[0061] The data acquisition module is used to acquire transient electromagnetic response data of each measuring line in the target working area; the measuring line includes multiple measuring points; the measuring points on different measuring lines at the same time constitute a time channel; the transient electromagnetic response data includes a plurality of transient electromagnetic response values.

[0062] The calculation module is used to calculate the correction coefficients of different measurement lines on each time channel according to the transient electromagnetic response data.

[0063] The correction module is used to correct the transient electromagnetic response value on the time channel based on the correction coefficient.

[0064] Wherein, the computing module comprises:

[0065] The first calculation submodule is used to calculate the , calculate the correction coefficients for different measurement lines on the first time channel.

[0066] The second calculation submodule is used to calculate the , calculate the correction coefficients for different survey lines on the non-first time channel.

[0067] In the formula, W The length is 2 q +1 weighted vector, starting with - q , the end mark is q , subscript i For the i Lines, c i1 is the correction coefficient for different measurement lines on the first time channel, c ik is the correction coefficient for different measurement lines on the non-first time channel, m is the number of measurement lines, n is the number of measuring points, subscript j For the j measurement points; subscript k Representative k A time road, For the i + l Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point, For the i + l Line j The corresponding measuring point k The transient electromagnetic response value of the time channel, l is the sequence number of the weight vector.

[0068] Wherein, the correction module comprises:

[0069] The first correction submodule is used to correct the transient electromagnetic response value on the first time channel based on the correction coefficients of different measurement lines on the first time channel.

[0070] The second correction submodule is used to correct the transient electromagnetic response value on the non-first time channel based on the correction coefficients of different measurement lines on the non-first time channel.

[0071] Specifically, the first correction submodule is used to calculate the , correct the transient electromagnetic response value on the first time channel.

[0072] in, c i1 is the correction coefficient of different measurement lines on the first time channel, with superscript r represents the corrected transient electromagnetic response,d ij1 For the i Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point.

[0073] In summary, this application has the following technical effects:

[0074] (1) Based on the raw transient electromagnetic data, this application realizes the correction of the system deviation between transient electromagnetic data measurement lines and eliminates the response deviation caused by working conditions.

[0075] (2) The transient electromagnetic data inter-line system deviation correction method proposed in this application can effectively solve the "banding" problem caused by the inter-line system deviation, improve the consistency of data between lines, and avoid interference with subsequent data analysis and interpretation.

[0076] (3) This application is based on the transient electromagnetic raw data, calculates the correction coefficient of the systematic deviation between survey lines through a specific formula, uses the calculated correction coefficient to correct the data of a single time channel, and finally obtains the correction coefficient of all time channels and different survey lines, thereby realizing the inter-survey line correction of all transient electromagnetic data, improving the consistency of data between different survey lines, and eliminating the systematic deviation between survey lines.

[0077] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for correcting the systematic deviation between transient electromagnetic data measurement lines, characterized in that: include: Acquire transient electromagnetic response data of each measuring line in the target working area; the measuring line includes a plurality of measuring points; the measuring points on different measuring lines at the same time constitute a time track; the transient electromagnetic response data includes a plurality of transient electromagnetic response values; For each of the time channels, calculating the correction coefficients of different measurement lines on the time channel according to the transient electromagnetic response data; For each of the time channels, the correction coefficients of different measurement lines on the time channel are calculated according to the transient electromagnetic response data, specifically including: According to the formula , calculate the correction coefficients of different survey lines on the first time track; According to the formula , calculate the correction coefficients for different survey lines on the non-first time track; Among them, W is the length of 2 q +1 weighted vector, starting with - q , the end mark is q , subscript i For the i Lines, c i1 is the correction coefficient for different measurement lines on the first time channel, c ik is the correction coefficient for different measurement lines on the non-first time channel, m is the number of measurement lines, n is the number of measuring points, subscript j For the j measurement points; subscript k represents the kth time channel, For the i + l Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point, For the i + l Line j The corresponding measuring point k The transient electromagnetic response value of the time channel, l is the sequence number of the weighted vector; Based on the correction coefficient, the transient electromagnetic response value on the time channel is corrected.

2. A method for correcting the system deviation between transient electromagnetic data measurement lines according to claim 1, characterized in that: The transient electromagnetic response data is composed of transient electromagnetic response matrices of several measuring lines; the transient electromagnetic response matrix on any measuring line includes: several transient electromagnetic response vectors, each transient electromagnetic response vector corresponds to a measuring point on the measuring line; the transient electromagnetic response vector is composed of several transient electromagnetic response values.

3. The method for correcting the system deviation between transient electromagnetic data measurement lines according to claim 1 is characterized in that: Based on the correction coefficient, the transient electromagnetic response value on the time channel is corrected, specifically including: Based on the correction coefficients of different measuring lines on the first time channel, the transient electromagnetic response value on the first time channel is corrected; Based on the correction coefficients of different survey lines on the non-first time channel, the transient electromagnetic response values ​​on the non-first time channel are corrected.

4. The method for correcting the system deviation between transient electromagnetic data lines according to claim 3 is characterized in that: Based on the correction coefficients of different measuring lines on the first time channel, the correction formula for correcting the transient electromagnetic response value on the first time channel is: ； in, c i1 is the correction coefficient of different measurement lines on the first time channel, with superscript r represents the corrected transient electromagnetic response, d ij1 For the i Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point.

5. The method for correcting the system deviation between transient electromagnetic data measurement lines according to claim 1 is characterized in that: Based on the correction coefficients of different measurement lines on the non-first time channel, the correction formula for correcting the transient electromagnetic response value on the non-first time channel is: ； in, c ik is the correction coefficient of different measurement lines on the non-first time channel, with superscript r represents the corrected transient electromagnetic response, d ijk For the i Line j The corresponding measuring point k The transient electromagnetic response value of a time channel.

6. A system for correcting the systematic deviation between transient electromagnetic data measurement lines, characterized in that: include: A data acquisition module is used to acquire transient electromagnetic response data of each measuring line in the target working area; the measuring line includes a plurality of measuring points; the measuring points on different measuring lines at the same time constitute a time channel; the transient electromagnetic response data includes a plurality of transient electromagnetic response values; A calculation module, for calculating, for each of the time channels, correction coefficients of different measurement lines on the time channel according to the transient electromagnetic response data; The computing module comprises: The first calculation submodule is used to calculate the , calculate the correction coefficients of different survey lines on the first time track; The second calculation submodule is used to calculate the , calculate the correction coefficients for different survey lines on the non-first time track; Among them, W is the length of 2 q +1 weighted vector, starting with - q , the end mark is q , subscript i For the i Lines, c i1 is the correction coefficient for different measurement lines on the first time channel, c ik is the correction coefficient for different measurement lines on the non-first time channel, m is the number of measurement lines, n is the number of measuring points, subscript j For the j measurement points; subscript k Representative k A time road, For the i + l Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point, For the i + l Line j The corresponding measuring point k The transient electromagnetic response value of the time channel, l is the sequence number of the weighted vector; The correction module is used to correct the transient electromagnetic response value on the time channel based on the correction coefficient.

7. A system for correcting the system deviation between transient electromagnetic data measurement lines according to claim 6, characterized in that: The correction module comprises: A first correction submodule, used for correcting the transient electromagnetic response value on the first time channel based on the correction coefficients of different measurement lines on the first time channel; The second correction submodule is used to correct the transient electromagnetic response value on the non-first time channel based on the correction coefficients of different measurement lines on the non-first time channel.

8. A system for correcting the system deviation between transient electromagnetic data measurement lines according to claim 7, characterized in that: The first correction submodule is used to , correct the transient electromagnetic response value on the first time channel; in, c i1 is the correction coefficient of different measurement lines on the first time channel, with superscript r represents the corrected transient electromagnetic response, d ij1 For the i Line j The transient electromagnetic response value corresponding to the first time channel at each measuring point.

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