CN-120722438-B - Inversion method for self-adaptive time-frequency data correction based on apparent resistivity average slope

CN120722438BCN 120722438 BCN120722438 BCN 120722438BCN-120722438-B

Abstract

The invention discloses an inversion method for self-adaptive time-frequency data correction based on a visual resistivity average slope, which comprises the steps of obtaining time-frequency data, obtaining the visual resistivity average slope, correcting the time-frequency data by adopting the visual resistivity average slope and a self-adaptive time-frequency data correction factor to obtain corrected time-frequency data, constructing an inversion data objective function, and inverting the corrected time-frequency data. Through the scheme, the method has the advantages of simple logic, accuracy, reliability and the like, and has high practical value and popularization value in the technical field of geophysical electromagnetic method exploration.

Inventors

WANG KUNPENG
YANG KAIMING
YU CHANGHENG
LIN JUNKAI
ZHANG YU
WANG YINGPING

Assignees

成都理工大学

Dates

Publication Date: 20260508
Application Date: 20250630

Claims (3)

1. The inversion method for adaptive time-frequency data correction based on the average slope of apparent resistivity is characterized by comprising the following steps of: acquiring electromagnetic time-frequency data, and obtaining the average slope of apparent resistivity; presetting an adaptive time-frequency data correction factor, correcting the time-frequency data by adopting an average slope of apparent resistivity and the adaptive time-frequency data correction factor to obtain corrected time-frequency data, wherein the expression is as follows: Wherein, the Representing observation data before correction of the adaptive time-frequency data correction factor; representing the data after the self-adaptive time-frequency data correction; Representing the correction coefficient; Representing an adaptive time-frequency data correction factor; Constructing an inversion data objective function, and inverting the corrected time-frequency data, wherein the expression of the inversion data objective function is as follows: ; Wherein, the Representing a frequency domain adaptive time-frequency data correction coefficient matrix; representing a frequency domain data weighting matrix; representing a frequency domain observation data matrix; representing a frequency domain forward data matrix; representing a frequency domain control matrix; representing a time domain adaptive time-frequency data correction coefficient matrix; representing a time domain data weighting matrix; representing a time domain observation data matrix; Representing a time domain forward data matrix; T represents the transposition of the matrix; the correction coefficient The expression of (2) is: Wherein, the Represents the apparent resistivity average slope; Or the correction coefficient The expression of (2) is: Wherein, the E represents the bottom of natural logarithm; Or the correction coefficient The expression of (2) is: Wherein, the E represents the bottom of natural logarithm; Representing the frequency; Or the correction coefficient The expression of (2) is: Wherein, the E represents the bottom of natural logarithm; Representing time; the apparent resistivity average slope Is the average of the absolute values of the slopes of the current data point and the neighboring data points.
2. The inversion method of adaptive time-frequency data correction based on apparent resistivity mean slope according to claim 1, wherein the apparent resistivity mean slope The determination of (1) comprises the following steps: if the time-frequency data is one-dimensional, obtaining two adjacent time-frequency data according to the front and rear of the time-frequency data point; if the time-frequency data is two-dimensional, eight adjacent time-frequency data around the time-frequency data point are obtained; If the time-frequency data is three-dimensional, 26 time-frequency data adjacent to the periphery of the time-frequency data point are obtained.
3. The inversion method of adaptive time-frequency data correction based on apparent resistivity average slope according to claim 1, wherein the adaptive time-frequency data correction factor The method is obtained by adopting an inflection point method or a lowest point method.

Description

Inversion method for self-adaptive time-frequency data correction based on apparent resistivity average slope Technical Field The invention relates to the technical field of geophysical electromagnetic method exploration, in particular to an inversion method for self-adaptive time-frequency data correction based on apparent resistivity average slope. Background At present, deep and medium resource exploration faces the bottleneck of weak signal detection in the field of electromagnetic methods, particularly in engineering geophysical prospecting, electromagnetic signals are exponentially attenuated along with the increase of depth due to complex geological environment, and therefore the prior art is difficult to effectively capture deep electromagnetic abnormal signals. The electromagnetic response signals of targets such as blind ore bodies, geothermal reservoirs and the like are often weak and are easily covered by background noise. For exploration of these deep resources, the existing electromagnetic method technology cannot well cope with the problems of weak signals and fuzzy abnormal characteristics, and the difficulty of signal capturing and analysis is caused. Particularly, under the high-temperature and high-pressure environment, the electromagnetic signal abnormal performance of the geothermal reservoir is more complex, and the difficulty of signal identification and analysis is further increased. Therefore, how to improve the sensitivity detection technology of deep weak electromagnetic signals, develop a more efficient weak electromagnetic abnormal signal identification algorithm, solve the problem of multiple solutions in weak signal inversion modeling, and become a key technical problem to be solved urgently. Aiming at the problem that the middle-deep abnormal signal is weak and difficult to detect, the traditional geophysical electric method has the defects of low precision and weak effective information, and has insufficient inversion resolution and reliability. For example, the disclosure technology of the disclosure number CN117270072A, named as the gravity field imaging inversion method and system based on the improved differential evolution algorithm, includes denoising and separating the area field from the gravity field data to obtain residual field data, generating an initial model of an underground medium and a physical property parameter range constraint, reading the residual field data and the initial model, generating an inversion grid parameter and priori information matrix, establishing an inversion objective function of imaging inversion, optimizing the inversion objective function by using the improved differential evolution algorithm, and finally outputting a model vector with the minimum data objective function as a final inversion result. The patent may suffer from the disadvantage that the success of the method is severely dependent on the design of the population model, and for complex models the reliability of the results is not guaranteed. In addition, in the disclosure technology of CN109828307A, named a transient electromagnetic multi-frequency fusion detection method and application, a plurality of groups of emission frequencies are utilized to collect experimental data of different induced electromotive forces and different time channel distributions, the data obtained by fusing multiple frequencies in a coincident time domain and the data of each frequency specific time domain are combined in time sequence to obtain multi-frequency fusion data, the combined data is partitioned in the time domain to realize average time channel distribution to obtain an induced electromotive force attenuation curve, the junction of regression fusion data and the data of the multiple frequency specific time domains is subjected to smooth processing, the average time channel distribution is adopted, and the smoothed data is substituted into the original data to perform two-dimensional imaging inversion to obtain a resistivity profile. The problem with this patent is to emphasize that the rounding of the data is very likely to result in the elimination of weak anomaly signals in practical complications, inability to improve inversion resolution, and potential further degradation of inversion resolution. At present, in the research of deep and medium resource exploration, a unified high-efficiency technical scheme is not formed by an effective inversion method aiming at weak abnormal signals. In engineering geophysical prospecting, due to the influence of underground complex media, as the detection depth increases, electromagnetic signals of a target body are gradually attenuated, physical differences between an ore body and surrounding rock are small, weak electromagnetic abnormal signals are easily submerged by background noise, and the prior art is difficult to effectively identify. In addition, in mineral resource exploration, as the depth increases, the electromagnetic signals of t