A method for extracting induced polarization measurement anomalies

Abstract

The application provides a method for extracting induced polarization measurement anomaly, comprising the following steps: a, counting each lithology apparent resistivity value and apparent polarization rate value; b, dividing the working area according to the apparent resistivity contour plan and the apparent polarization rate contour plan; c, calculating the normalized value of the apparent polarization rate of each measuring point in each partition; d, calculating the apparent video dispersion conductivity average value of all measuring points in each partition; e, calculating the apparent polarization rate derivative value of all measuring points; f, drawing the apparent polarization rate derivative value contour plan by using basic drawing software; g, delineating the apparent polarization rate derivative anomaly. The application is based on the reliability of induced polarization anomaly normalization and secondary anomaly information extraction, focuses on removing the area anomaly with larger area and more stable high value, and comprehensively analyzes the polarization rate and the resistivity in different partitions, so that the secondary anomaly information of the induced polarization measurement is better extracted, and the ore-induced anomaly is more accurately evaluated.

Description

TECHNICAL FIELD

[0001] The present application relates to an extraction method, in particular to an induced polarization measurement anomaly extraction method. BACKGROUND

[0002] A large number of induced polarization anomalies have been extracted by predecessors, and a large number of induced polarization anomalies have been delineated. The method has good effect in the exploration process of metal mines (especially sulfide metal mines), can quickly and effectively locate the polarization body at a certain depth, and has been widely used. In the past, the extraction of induced polarization anomaly generally takes large-area low and stable polarization rate value as the "normal background value", extracts apparent polarization rate anomaly combined with the standard deviation of background value, and evaluates stratum structure, lithological characteristics, fractures and anomalies combined with apparent resistivity characteristics. At present, how to highlight the low-resistance polarization body anomaly related to mineralization and suppress the induced polarization measurement anomaly unrelated to mineralization has become a difficult problem in induced polarization measurement work. Accurate identification and evaluation of mineral-induced induced polarization anomaly have positive significance for geophysical prospecting.

[0003] In recent years, with the development of anomaly extraction technology, scholars at home and abroad have successfully applied video scattered conductivity method to highlight low-resistance induced polarization anomaly to a certain extent. How to reduce the multi-solution of induced polarization anomaly interpretation and accurately distinguish mineral and non-mineral anomaly has always been an important topic for geophysical workers to study. It is difficult to accurately evaluate induced polarization anomaly under different lithological backgrounds by using conventional induced polarization measurement apparent polarization rate. SUMMARY

[0004] The purpose of the present application is to provide an induced polarization measurement anomaly extraction method to solve the problem of inaccurate existing induced polarization anomaly extraction results.

[0005] The present application is implemented as follows: an induced polarization measurement anomaly extraction method, comprising the following steps:

[0006] a. According to the measured physical property parameters, the apparent polarization rate values of each lithology are statistically analyzed, and the apparent resistivity values and apparent polarization rate values of each lithology are counted;

[0007] b. Using basic mapping software to make apparent resistivity contour plan and apparent polarization rate contour plan of all measuring points, and combining with geological data, the working area is divided according to the apparent resistivity contour plan and apparent polarization rate contour plan, and the normalized value of apparent polarization rate of each measuring point in each partition is calculated according to the counted apparent polarization rate values of different lithologies and the measured apparent polarization rate values of each measuring point in step a;

[0008] c. According to the normalized value of apparent polarization rate of each measuring point in each partition and the measured apparent resistivity value, the video scattered conductivity value of each measuring point in each partition is calculated, and the average value of video scattered conductivity of all measuring points in each partition is calculated;

[0009] d. Based on the average video divergence conductivity of all measurement points in each partition calculated in step c and the video divergence conductivity value of each measurement point, combined with the measured visual polarizability value of each measurement point, calculate the derived visual polarizability value of all measurement points.

[0010] e. Based on the apparent polarizability derived value of each measuring point obtained in step d, and combined with the measuring point coordinates, draw a contour map of the apparent polarizability derived value using basic drawing software.

[0011] f. Based on the contour map of apparent polarizability derived values ​​obtained in step e, the apparent polarizability derived anomalies are delineated using the distribution characteristics of apparent polarizability derived value anomalies in known mineral deposits.

[0012] Furthermore, the present invention can be implemented according to the following technical solution:

[0013] In step b, the formula for calculating the normalized value of the apparent polarizability of each measurement point in each partition is as follows:

[0014] η ig =η i -(η n -η1) (1)

[0015] In the formula: η ig η represents the normalized apparent polarizability value of the nth partition and the ith measurement point. i η represents the measured apparent polarizability value of the nth partition and the ith measurement point. n η represents the apparent polarizability value of the lithology in the nth partition, and η1 represents the apparent polarizability value of the partition with the lowest apparent polarizability value.

[0016] In step c,

[0017] The formula for calculating the video dispersion conductivity value at each measurement point in each partition is as follows:

[0018]

[0019] The formula for calculating the average video dispersion conductivity of all measurement points in each zone is as follows:

[0020]

[0021] In the formula: η s η represents the video dispersion conductivity value at each measurement point. ig ρ represents the normalized apparent polarizability value of the i-th measurement point in each partition. i This represents the measured apparent resistivity value at the i-th measuring point in each partition. η represents the average video dispersion conductivity of all measurement points in different zones. is represents the video dispersion conductivity value of the i-th measurement point in different partitions, and n represents the number of measurement points in the same partition.

[0022] In the step d,

[0023] The formula for calculating the apparent polarizability derived value of all measuring points is as follows:

[0024]

[0025] In the formula, μ i represents the apparent polarizability derived value of the i-th measuring point in each subarea, η s represents the video-spreading conductivity value of each measuring point, represents the video-spreading conductivity average value of all measuring points in different subareas, η i represents the measured apparent polarizability value of the i-th measuring point in each subarea.

[0026] Based on the reliability of the normalized IP anomaly and the secondary anomaly information extraction, the present application focuses on removing the area anomaly with a large area and a stable high value, and can divide the working area according to the lithology, normalize the IP measurement anomaly under different lithological backgrounds, and comprehensively analyze the polarizability and resistivity of different subareas, so as to better extract the secondary IP measurement anomaly information and more accurately evaluate the ore-induced anomaly.

[0027] The calculation basis of the present application is that the apparent polarizability value and the resistivity of the same lithology are roughly the same when the lithology is not altered and mineralized, and the apparent polarizability derived value is also roughly the same. When the rock is broken and altered due to tectonic movement, even mineralized, the resistivity and polarizability will also change accordingly, and the apparent polarizability derived value will also change, which is directly related to the lithology, breaking, alteration, mineralization, etc. Therefore, based on the apparent resistivity contour map and the apparent polarizability contour map, combined with geological data, the working area is divided, the apparent polarizability value under different lithological backgrounds is normalized according to the polarizability characteristics of different lithologies, so as to remove the regional IP anomaly caused by different lithologies and better highlight the mineralization anomaly. Then, based on the normalized apparent polarizability data, combined with the different apparent resistivity change characteristics of the same lithology, the apparent polarizability derived value distribution characteristics of the IP measurement are formed, and this parameter can more effectively reflect the distribution of the underground ore-induced polarization anomaly body. The method can be used to extract multiple information superimposed on the IP measurement anomaly, and good application has been achieved in the previous polymetallic prospecting. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the flowchart of the present application.

[0029] Figure 2 is the apparent resistivity contour map of the research area

[0030] Figure 3 is the apparent polarizability contour map of the research area

[0031] Figure 4 is a contour map of apparent polarizability derived value of the study area DETAILED DESCRIPTION

[0032] As Figure 1 shown, the induced polarization measurement anomaly extraction method of the present application comprises the following steps:

[0033] a. According to the measured physical parameters, the apparent resistivity and apparent polarizability values of each lithology are statistically analyzed, and the apparent resistivity and apparent polarizability values of each lithology are counted; and the basic parameters are provided for the normalization of the apparent polarizability values under different lithology backgrounds in the later stage.

[0034] b. The basic drawing software is used to make the apparent resistivity contour map and the apparent polarizability contour map of all measurement points, as shown in Figure 2 and Figure 3 , combined with geological data, based on the apparent resistivity contour map and the apparent polarizability contour map, the working area is divided, and according to the apparent polarizability values of different lithologies and the measured apparent polarizability values of each measurement point obtained in step a, the normalized values of the apparent polarizability of each measurement point in each partition are calculated.

[0035] The formula for calculating the normalized value of the apparent polarizability of each measurement point in each partition is as follows:

[0036] η ig = η i - (η n - η1) (1)

[0037] In the formula, η ig represents the normalized value of the apparent polarizability of the i-th measurement point in the n-th partition, η i represents the measured apparent polarizability value of the i-th measurement point in the n-th partition, η n represents the lithology apparent polarizability value of the n-th partition, and η1 represents the apparent polarizability value of the lowest partition in the apparent polarizability value of each partition.

[0038] c. According to the normalized value of the apparent polarizability of each measurement point in each partition and the measured apparent resistivity value, the video dispersion conductivity value of each measurement point in each partition is calculated, and the average value of the video dispersion conductivity of all measurement points in each partition is calculated.

[0039] The formula for calculating the video dispersion conductivity value of each measurement point in each partition is as follows:

[0040]

[0041] The formula for calculating the average value of the video dispersion conductivity of all measurement points in each partition is as follows:

[0042]

[0043] ηi s ηi represents the video specific conductivity value of each measuring point ig ηi represents the normalized value of the video specific conductivity of the i th measuring point in each partition i ηi represents the measured video specific resistivity value of the i th measuring point in each partition ηi represents the average value of the video specific conductivity of all measuring points in different partitions is ηi represents the video specific conductivity value of the i th measuring point in different partitions, and n represents the number of measuring points in the same partition.

[0044] d、According to the average value of the video specific conductivity of all measuring points in each partition calculated in step c and the video specific conductivity value of each measuring point, the derived value of the video specific resistivity of all measuring points is calculated.

[0045] The formula for calculating the derived value of the video specific resistivity of all measuring points is as follows:

[0046]

[0047] μi i μi represents the derived value of the video specific resistivity of the i th measuring point in each partition s ηi represents the video specific conductivity value of each measuring point ηi represents the average value of the video specific conductivity of all measuring points in different partitions i ηi represents the measured video specific resistivity value of the i th measuring point in each partition

[0048] e、According to the derived value of the video specific resistivity of each measuring point obtained in step d, combined with the measuring point coordinates, the basic drawing software is used to draw the video specific resistivity derived value contour plane, as shown in Figure 4 .

[0049] f、According to the video specific resistivity derived value contour plane obtained in step e, the distribution characteristics of the video specific resistivity derived value anomaly in known ore spots are used to delineate the video specific resistivity derived anomaly.

[0050] Specifically, the ore area is located in the video specific resistivity derived anomaly area, which has a good correspondence with the induced video specific resistivity derived anomaly. This type of anomaly removes the non-mineral caused area anomaly with large area and stable high value. The data is partitioned, and the low resistance high polarization body anomaly in different partitions is highlighted, and the high resistance high polarization body anomaly is removed. Figure 3 According to the four anomalies delineated by the video specific resistivity in the working area, after the extraction of the video specific resistivity derived value, by Figure 4It can be seen that the scale and amplitude of the 1st and 2nd anomalies are significantly enhanced, the amplitude of the 3rd anomaly is relatively weakened, and the 4th anomaly is a high-resistance high-polarization anomaly, which is different from the metallogenic model in the area, and the anomaly disappears. The application effect is better in the metallogenic type in which the polymetallic metallogenic type is controlled by tectonic fracture and alteration zone, and the ore body presents a low-resistance high-polarization body. Therefore, by extracting the polarization rate derivative value anomaly of the research area, a basis and reference can be provided for polymetallic ore prospecting in the research area.

Claims

1. A method for extracting induced polarization measurement anomalies, characterized by, It comprises the following steps: a. Statistically analyzing the apparent resistivity and apparent polarizability values of each lithology according to the measured physical property parameters, and counting the apparent resistivity and apparent polarizability values of each lithology; b. Using basic drawing software to make the apparent resistivity contour plan and apparent polarizability contour plan of all measuring points, and combining with the geological data, taking the apparent resistivity contour plan and apparent polarizability contour plan as the basis to divide the working area, and according to the apparent polarizability values of different lithologies obtained by statistical analysis in step a and the measured apparent polarizability values of each measuring point, calculating the normalized value of the apparent polarizability of each measuring point in each division; c. According to the normalized value of the apparent polarizability of each measuring point in each division and the measured apparent resistivity value, calculating the video scattering conductivity value of each measuring point in each division, and calculating the average value of the video scattering conductivity of all measuring points in each division; d. According to the average value of the video scattering conductivity of all measuring points in each division calculated in step c and the video scattering conductivity value of each measuring point, combining with the measured apparent polarizability value of each measuring point, calculating the apparent polarizability derivative value of all measuring points; e. According to the apparent polarizability derivative value of each measuring point obtained in step d, combining with the measuring point coordinates, using basic drawing software to draw the apparent polarizability derivative value contour plan; f. According to the apparent polarizability derivative value contour plan obtained in step e, using the distribution characteristics of the apparent polarizability derivative value anomaly in known ore spots to delineate the apparent polarizability derivative anomaly.

2. The induced polarization measurement anomaly extraction method according to claim 1, characterized in that, in In step b, the formula for calculating the normalized value of the apparent polarizability of each measuring point in each division is as follows: η ig = η i -(η n -η1) (1) In the formula: η ig η represents the normalized apparent polarizability value of the nth partition and the ith measurement point. i η represents the measured apparent polarizability value of the nth partition and the ith measurement point. n η represents the apparent polarizability value of the lithology in the nth partition, and η1 represents the apparent polarizability value of the partition with the lowest apparent polarizability value.

3. The method according to claim 1, wherein the step of extracting the induced polarization measurement anomaly is characterized by In step c, The formula for calculating the video scattering conductivity value of each measuring point in each division is as follows: The formula for calculating the average value of the video scattering conductivity of all measuring points in each division is as follows: wherein: η s η represents the video conductivity value of each measuring point ig ρ represents the normalized value of the video resistivity of the i th measuring point in each partition i η represents the measured video resistivity value of the i th measuring point in each partition η represents the average value of the video conductivity of all measuring points in different partitions is η represents the video conductivity value of the i th measuring point in different partitions, and n represents the number of measuring points in the same partition.

4. The induced polarization measurement anomaly extraction method according to claim 1, characterized in that, in In step d, The formula for calculating the apparent polarizability derivative value of all measuring points is as follows: where: μ i ηi represents the derived apparent polarizability value for the i-th measurement point in each partition s η represents the video specific conductivity value for each measurement point η represents the average video specific conductivity value for all measurement points in different partitions i ηi represents the measured apparent polarizability value for the i-th measurement point in each partition

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