CN-122018016-A - Electrical anomaly transient electromagnetic three-dimensional positioning method

Abstract

The invention relates to the technical field of electromagnetic detection, in particular to an electrical anomaly transient electromagnetic three-dimensional positioning method which comprises the steps of obtaining transient electromagnetic three-component response data of each measuring point according to detection requirements, carrying out matrix transformation on data of all the measuring points by adopting a constructed transformation matrix to obtain transformed transient electromagnetic response data, calculating the directional vector of each measuring point in each time channel based on the transformed transient electromagnetic response data, calculating the positioning line segment of each measuring point in each time channel based on the coordinates of each measuring point and the corresponding directional vector of each measuring point, selecting a certain time channel, drawing the positioning line segments of all the measuring points, and picking up the intersection points of the positioning line segments to determine the spatial position of an electrical anomaly. According to the method, the transient electromagnetic three-component response data are transformed and directly calculated to position the line segment, the three-dimensional space position of the electrical abnormal body can be determined without depending on iterative inversion, the positioning precision and the uniqueness of the positioning result are effectively improved, and the calculation efficiency is improved.

Inventors

• WU QIONG
• ZHI QINGQUAN
• WU JUNJIE

Assignees

• 中国地质科学院地球物理地球化学勘查研究所

Dates

Publication Date

20260512

Application Date

20260415

Claims (9)

1. 1. The electrical abnormal body transient electromagnetic three-dimensional positioning method is characterized by comprising the following steps of: s1, carrying out transient electromagnetic measurement according to detection requirements, and acquiring transient electromagnetic three-component response data of each measuring point; s2, carrying out transformation processing on the transient electromagnetic three-component response data through a constructed transformation matrix T to obtain transformed transient electromagnetic response data; S3, calculating the pointing vector C ij of each measuring point in each time channel based on the transformed transient electromagnetic response data; s4, calculating a positioning line segment of each measuring point in each time channel based on the coordinates of each measuring point and the corresponding pointing vector C ij ; S5, selecting a certain time channel, drawing positioning line segments of all measuring points, and picking up intersection points of the positioning line segments, so that the spatial position of the electrical abnormal body is determined.
2. 2. The method according to claim 1, wherein in step S1, the acquired transient electromagnetic three-component response data is stored as a data set L: L=[D 1 ,D 2 ,…,D i ,…,D m ]; Wherein L is a transient electromagnetic data set of different measuring points, i is a measuring point number, the corresponding coordinate is P i = [x i , y i , z i ];D i , the corresponding coordinate is the transient electromagnetic three-component response data of the ith measuring point, and m is the number of measuring points.
3. 3. The method for three-dimensional localization of electrical anomalies by transient electromagnetic according to claim 2, wherein the transient electromagnetic three-component response data D i is a matrix of 3 rows and n columns: ; n is the number of time channels of each measuring point, d xij is the x-component transient electromagnetic response value of the jth time channel t j of the corresponding ith measuring point, d yij is the y-component transient electromagnetic response value of the jth time channel t j of the corresponding ith measuring point, and d zij is the z-component transient electromagnetic response value of the jth time channel t j of the corresponding ith measuring point.
4. 4. A method for three-dimensional positioning of transient electromagnetic signals of an electrical anomaly body according to claim 3, wherein in step S2, the order n of the constructed transformation matrix T is equal to the length of the transient electromagnetic response time sequence and the number of channels, and the constructed transformation matrix T is used for performing matrix transformation on the transient electromagnetic three-component response data of each measuring point; The sum of values of each row of the constructed transformation matrix T is 1, each point before and after each row is smoothed, for the first row, T (1, 1) =2/3, T (1, 2) =1/3, the rest elements of the first row are 0, and for the last row, T (n, n-1) =1/3, T (n, n) =2/3, the rest elements of the last row are 0, and n is the number of time channels.
5. 5. The method for three-dimensional positioning of transient electromagnetic signals of an electrical anomaly in accordance with claim 4, wherein in step S2, a constructed transformation matrix T is used to perform matrix transformation on the transient electromagnetic response data D i of all the measurement points, respectively, so as to obtain transformed transient electromagnetic response data { D i }={D i ×t }.
6. 6. The method for three-dimensional positioning of electrical abnormal body transient electromagnetic according to claim 3, wherein in step S3, the calculation formula of the pointing vector C ij is: ; Wherein, the B is a distance coefficient.
7. 7. The method of claim 6, wherein in step S4, for the jth time slot, the positioning line segments of the ith measurement point and the starting points of the line segments are calculated respectively Line segment end point ; C ij is the pointing vector of the ith measuring point at the jth time channel, which is the coordinate of the ith measuring point.
8. 8. The method for three-dimensionally positioning an electrical anomaly transient electromagnetic system according to claim 6, wherein the distance coefficient b is determined by man-machine interaction, and the determination principle is that positioning line segments can be intersected.
9. 9. The method for three-dimensional positioning of electrical anomalies by transient electromagnetic waves of claim 8, wherein the human-computer interaction is clicking the intersection of the pick-up positioning line segments with a pointing device.

Description

Electrical anomaly transient electromagnetic three-dimensional positioning method Technical Field The invention relates to the technical field of electromagnetic detection, in particular to an electrical anomaly transient electromagnetic three-dimensional positioning method. Background The transient electromagnetic method (TRANSIENT ELECTROMAGNETIC METHOD, TEM) is a geophysical prospecting method based on the principle of electromagnetic induction. The basic working process comprises the steps of sending a primary pulse magnetic field to the underground through arranging a transmitting coil, and measuring a secondary attenuation field caused by eddy currents induced by an underground medium after the primary field is suddenly turned off. By analyzing the change rule of the secondary attenuation field along with time, the electrical distribution structure of the underground medium can be deduced. The transient electromagnetic method has the characteristics of large detection depth, strong resolving power, sensitivity to low resistance and the like, and is widely applied to the fields of mineral resource exploration, underground water detection, engineering geological investigation, environmental geophysics and the like. In transient electromagnetic detection, accurate positioning of electrical anomalies is a critical technique. The current common positioning methods are mainly divided into two types, namely a direct positioning method based on transient electromagnetic response characteristics or apparent resistivity parameters and a model fitting positioning method based on inversion calculation (inversion). The first type of method typically makes inferences based on the magnitude of the anomaly response, time constant, or anomaly morphology in the apparent resistivity profile. Although the method is simple and convenient to calculate, the result is rough, the spatial resolution capability is limited, and accurate three-dimensional positioning is difficult to realize. The second method is to construct an earth model and repeatedly perform forward calculation to fit the observed data so as to reversely infer the distribution of the electrical parameters of the underground medium. The method can realize higher positioning precision in theory, but is limited by nonlinearity and multiple solutions of inversion problems in practical application. This often results in problems such as insufficient convergence stability, severe dependence of the calculation result on the selection of the initial model, and low calculation efficiency. Particularly, in the multi-parameter collaborative inversion, the calculation process is very easy to be trapped into a local extremum, so that the reliability and the spatial resolution capability of a positioning result are affected. Disclosure of Invention In view of the above, the invention provides a transient electromagnetic three-dimensional positioning method for an electrical anomaly, which aims to solve the problems of insufficient three-dimensional positioning precision, strong inversion interpretation multi-solution and low calculation efficiency of the underground electrical anomaly in the existing transient electromagnetic detection technology, thereby improving the accuracy, the uniqueness and the calculation efficiency of the spatial position determination of the electrical anomaly. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides an electrical anomaly transient electromagnetic three-dimensional positioning method, which comprises the following steps: s1, carrying out transient electromagnetic measurement according to detection requirements, and acquiring transient electromagnetic three-component response data of each measuring point; s2, carrying out transformation processing on the transient electromagnetic three-component response data through a constructed transformation matrix T to obtain transformed transient electromagnetic response data; S3, calculating the pointing vector C ij of each measuring point in each time channel based on the transformed transient electromagnetic response data; s4, calculating a positioning line segment of each measuring point in each time channel based on the coordinates of each measuring point and the corresponding pointing vector C ij; S5, selecting a certain time channel, drawing positioning line segments of all measuring points, and picking up intersection points of the positioning line segments, so that the spatial position of the electrical abnormal body is determined. In a specific embodiment, in step S1, the acquired transient electromagnetic three-component response data is stored as a data set L: L=[D1,D2,…,Di,…,Dm]; Wherein L is a transient electromagnetic data set of different measuring points, i is a measuring point number, the corresponding coordinate is P i= [xi,yi,zi];Di, the corresponding coordinate is the transient electromagnetic three-component resp