A method for correcting complex resistivity data of rock and mineral samples and a measuring device therefor

Abstract

The application discloses a method for correcting rock and mineral complex resistivity measurement data, which depends on two different acquisition circuit design schemes and is realized by signal source positive and negative connection interchanging. The method comprises the following steps: obtaining original impedance data of rock and mineral samples as target data by using a signal source positive connection circuit; obtaining impedance correction parameters by using a signal source negative connection circuit; and obtaining corrected complex resistivity data according to the signal source positive and negative connection correction method by using the original impedance data and the impedance correction parameters. The method can suppress the interference of internal acquisition channel distribution capacitance and sampling resistance parasitic capacitance of a test device, and realizes high-precision measurement of rock and mineral complex resistivity data in a 0.001Hz-100kHz wide frequency band range.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rock physics investigation and geophysical exploration technology, and particularly relates to a complex resistivity data correction method for rock and mineral samples and a measuring device thereof. BACKGROUND

[0002] Laboratory sample testing is helpful for the research on the relationship between rock and mineral physical parameters and geophysical field data, and is the basis for constructing a geologic geophysical model. Rock complex resistivity data measurement is an effective means for studying the internal structure, mineral composition and fluid chemical properties of rock and minerals. It is a geophysical method for describing the polarization intensity of rock by testing the frequency spectrum response characteristics of different samples under the condition of applying an external electric field. The complex resistivity data includes two pieces of information, the real part and the imaginary part. The real part reflects the flow ability of the conductive charge inside the sample, and the imaginary part is related to the aggregation of the polarization charge inside and on the surface of the sample. Due to the strong polarization (IP) effect of metal minerals under an external electric field, the complex resistivity measurement of the sample is commonly used in mineral exploration and development, and the application frequency is generally below 1 kHz. With the gradual improvement of the testing method and theory, the complex resistivity measurement is widely used in engineering environment investigation, hydrological investigation, medical engineering, plant pest control and other fields, and the measurement frequency is also extended from the traditional kHz to hundreds of kHz.

[0003] The polarization effect of the sample can reveal the relationship between its physical properties and material, structural characteristics. This polarization effect is sometimes extremely weak, such as in some non-mineralized sedimentary rock samples, the phase change is only a few millivolts, and the traditional measurement system cannot monitor the effective information. In order to describe the true polarization characteristics of the sample, higher requirements are put forward for the testing instrument and the measuring device. Especially in the high frequency part (>1 kHz), many studies have confirmed that the distributed capacitance of the internal acquisition channel of the instrument will cause significant phase error, so that the high frequency data must be calibrated before use. In addition to the internal circuit design and material selection of the instrument, the design of the measuring device is also extremely important. The measuring electrodes will produce polarization phenomenon at low frequency, there is electromagnetic coupling interference between the measuring lines, and the contact impedance caused by the structural design also challenges the accuracy of the measurement results, so it is necessary to analyze the errors of the whole complex resistivity measurement system.

[0004] At present, special rock and mineral complex resistivity measuring instruments are not popular, and most scholars often use impedance analyzers or LCR bridge instruments to replace them, such as Solartron-1260A impedance analyzer of Solartran Company in the United Kingdom and HP4194A impedance / gain-phase analyzer of Hewlett-Packard Company in the United States. When measuring, the above instruments often use low resistance sampling resistors, which are mainly used for measuring electronic components, and the input impedance is less than 1GΩ. However, in the process of rock and mineral testing, high impedance samples as high as 100MΩ or more are often encountered, and the use of small sampling resistors for testing leads to a decrease in the accuracy of the measurement results. While using large sampling resistors for testing will cause the leakage current of the acquisition channel to increase, and the influence of the parasitic capacitance of the sampling resistor itself on the test results will also further increase. Therefore, there is a lack of analysis and correction of the test results of different sampling resistors under high frequency conditions to restore the frequency spectrum response characteristics of the large impedance sample itself. SUMMARY

[0005] The technical problem solved by the present application is to provide a rock and mineral sample complex resistivity data correction method and a measuring device based on the signal source positive and negative connection circuit design schemes, which fuse the test data of the two test schemes to correct the rock sample complex resistivity data.

[0006] To solve the above technical problems, the technical scheme provided by the present application is as follows: a rock and mineral sample complex resistivity data correction method, characterized in that it includes correcting the wideband complex resistivity data of the rock sample according to the signal source positive and negative connection circuit design schemes, and the impedance data correction method of the rock and mineral sample includes:

[0007] I. obtaining the original impedance data of the rock and mineral sample as target data by using the signal source positive connection circuit;

[0008] II. obtaining impedance correction parameters by using the signal source negative connection circuit;

[0009] III. obtaining the corrected complex resistivity data according to the signal source positive and negative connection correction method by using the original impedance data and the impedance correction parameters;

[0010]

[0011] Wherein, Zx is the actual impedance of the measured sample, Zm1 is the impedance value obtained by the instrument using the signal source positive connection measurement method, Zm2 is the impedance value obtained by the instrument using the signal source negative connection measurement method, Zs is the actual impedance of the sampling resistor, |Zm1|, |Zm2|, |Zs| and respectively represent the amplitude and phase of the impedances Zm1, Zm2 and Zs, and i is the imaginary unit.

[0012] Further, the signal source positive and negative two acquisition circuit design scheme: the signal source positive circuit design scheme will be collected circuit design for four acquisition channels (201, 202, 203, 204), there is a distribution capacitor C generated by the amplifier (205) leakage current on the channel, sampling resistor Rs (206) in the signal source end side, due to its internal parasitic capacitance makes its real impedance value becomes Zs, the current first through the test sample Zx (208);

[0013] The signal source negative circuit design scheme is obtained by changing the signal source access direction of the signal source positive circuit design scheme, at this time the sampling resistor Rs (306) is in the signal source front end.

[0014] Further, the relationship between the sample impedance Zx and the measured impedance value Zm can be calculated, specifically including:

[0015] A, the signal source positive circuit design scheme sample actual impedance Zx is:

[0016]

[0017] Where: Zx is the actual impedance of the measured sample; Zm1 is the impedance value obtained by measuring and calculating in the form of the instrument positive circuit; Rs is the sampling resistor resistance; Zs is the actual impedance of the sampling resistor; ω is the angular frequency; i is the imaginary unit;

[0018] B, the signal source negative circuit design scheme sample actual impedance Zx is:

[0019]

[0020] Where: Zx is the actual impedance of the measured sample, Zm1 is the impedance value obtained by measuring and calculating, Rs is the sampling resistor resistance, Zs is the actual impedance of the sampling resistor, ω is the angular frequency; i is the imaginary unit.

[0021] Further, the original impedance data of the rock and mineral sample obtained by the signal source positive circuit is used as the target data, specifically including:

[0022] A, the rock sample is clamped in the middle of the sample holder, after fixing, the BNC three coaxial measurement line is connected to the test equipment and the sample holder, and the instrument host data measurement mode is adjusted to the signal source positive measurement form;

[0023] B, according to the sampling resistor resistance matching method, the optimal sampling resistor Rs required for testing is determined;

[0024] C. Adjust the instrument sampling resistance to the optimal sampling resistance Rs. Select the test frequency range and frequency points according to requirements. The maximum frequency range achieved by the complex resistivity correction method is 0.001Hz-100kHz. Perform sweep frequency measurements at different frequencies from high to low frequency in sequence to obtain the impedance value Zm1 of the rock and ore sample in the form of a positive circuit with the signal source, which is used as the target data for correction.

[0025] Furthermore, the sampling resistor value matching method is used to determine the optimal sampling resistor Rs. The matching method is as follows:

[0026] A. Using the default sampling resistance of 1kΩ, perform two impedance measurements on the rock and mineral sample at a frequency of 1Hz. Calculate the error based on the two measurement results. If the error is less than or equal to 1%, average the two measurement results and save them. If the error is greater than 1%, return to the above steps and perform two more data measurements.

[0027] B. Calculate the optimal sampling resistor Rs based on the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz. If the calculated resistance is greater than 1MΩ, select a 1MΩ sampling resistor. If the calculated resistance is less than 100Ω, select a 100Ω sampling resistor.

[0028] Sampling resistor resistance matching formula:

[0029]

[0030] Rs is the sampling resistor that needs to be selected, and Zm1(1Hz) is the rock sample impedance value at 1Hz.

[0031] Furthermore, the impedance correction parameters are obtained by using a signal source reverse connection circuit, specifically including:

[0032] A. Adjust the test equipment's signal source connection direction to reverse polarity, and use a BNC triaxial measurement cable to connect the test equipment to the calibration board. The calibration board is equipped with five resistance models: 100Ω, 1kΩ, 10kΩ, 100kΩ, and 1MΩ. These models are consistent with the sampling resistor models inside the instrument.

[0033] B. According to the calculation method of the distributed capacitance of the acquisition channel of the reverse circuit, the distributed capacitance C of the four acquisition channels is obtained;

[0034] C. Test the impedance of the sampling resistor on the calibration board according to the reverse connection circuit of the signal source. At the same time, the sampling resistor selected by the test equipment is the optimal sampling resistor Rs. The test frequency is selected from 100kHz to 0.001Hz. Record the measured impedance value Zm2 in the reverse connection circuit.

[0035] D. Obtain the actual impedance Zs of the sampling resistor according to the actual impedance calculation method of the sampling resistor.

[0036] Further, the reverse connection circuit acquisition channel distribution capacitance calculation method obtains four acquisition channel distribution capacitances C, and the calculation method is as follows:

[0037] A. Two impedance measurements are performed on the 1kΩ resistor on the correction plate at a frequency of 100 kHz, and the default sampling resistor 1kΩ is used for testing; according to the two measurement results, the error is calculated, and when the error is less than or equal to 1%, the average value of the two measurement results is obtained Zm2(100kHz) and saved; when the error is greater than 1%, the two data measurements are performed again;

[0038] B. According to the acquisition channel distribution capacitance calculation formula, the four acquisition channel distribution capacitances C are calculated

[0039]

[0040] C is the acquisition channel distribution capacitance; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained by the signal source reverse connection measurement method at 100kHz; Rs is the sampling resistor resistance value; f100k=100kHz is the highest frequency of the test.

[0041] Further, the sampling resistor actual impedance calculation method obtains the actual impedance Zs of the sampling resistor, and the calculation method is as follows:

[0042]

[0043] Zs is the actual impedance of the sampling resistor; Zm2 is the measured impedance of the optimal sampling resistor in the reverse connection circuit form; Rs is the resistance value of the optimal sampling resistor; ω is the angular frequency; C is the distribution capacitance on the acquisition channel; i is the imaginary unit.

[0044] Further, according to the signal source forward and reverse connection correction method, the corrected complex resistivity data is obtained by using the original impedance data and the impedance correction parameter, specifically including:

[0045] A. According to the complex resistivity data correction method, the impedance value Zm1 of the test sample obtained by the signal source forward connection measurement method, that is, the target data, the measured impedance value Zm2 of the optimal sampling resistor in the reverse connection circuit form, and the actual impedance value Zs of the optimal sampling resistor Rs are used for rock and mineral impedance data correction;

[0046] Rock and mineral sample complex resistivity correction method:

[0047]

[0048] Zx is the corrected actual impedance of the rock sample; Zm1 is the target data before correction; Zm2 is the impedance measured by the optimal sampling resistor in the reverse connection circuit form; Zs is the actual impedance of the sampling resistor; Rs is the resistance value of the sampling resistor; |Zm1|, |Zm2|, |Zs| and |Zm1|, |Zm2|, |Zs| and |Zx| respectively represent the amplitude and phase of the impedances Zm1, Zm2 and Zs; i is the imaginary unit;

[0049] B, the impedance data of the corrected rock sample is converted into impedance amplitude |Zx| and phase According to the sample size, the impedance amplitude is converted into complex resistivity amplitude px according to the resistance law, and the complex resistivity phase is still

[0050] Further, it comprises a power supply electrode, a measurement electrode, a fixer and a sample holder container;

[0051] The power supply electrode adopts a surface-shaped purple copper alloy material to provide a stable power supply current;

[0052] The measurement electrode adopts an AgCl point-shaped reference electrode to avoid the influence of electrode self-polarization on the measurement result;

[0053] The fixer mainly adopts a knob fixing scheme, and after clamping the rock sample, the knob is tightened to fix the rock sample to prevent the rock sample from falling off during the test;

[0054] The sample holder container is filled with saturated copper sulfate solution inside to reduce the stray impedance between the power supply electrode and the receiving electrode.

[0055] After the above method, the present application has the following advantages: a complex resistivity data correction method for rock and mineral samples. The original impedance data of the rock and mineral sample is obtained by a signal source positive connection circuit as target data, the impedance correction parameter is obtained by a signal source reverse connection circuit, and the corrected complex resistivity data is obtained according to the signal source positive and negative connection correction method by using the original impedance data and the impedance correction parameter. Specifically, through the above operation steps, the present application can effectively eliminate the measurement error caused by factors such as the distribution capacitance of the acquisition channel and the parasitic capacitance of the sampling resistor, reduce the influence of the device effect on the test result by combining the sample holder design scheme, improve the measurement precision of the complex resistivity data of the rock and mineral sample, and has the advantages of high data precision, wide application range and simple operation. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is a flowchart of the complex resistivity data correction method for rock and mineral samples provided by the embodiment of the present application;

[0057] Figure 2This is a simplified acquisition circuit model diagram of the signal source positive connection test solution provided by an embodiment of the present invention;

[0058] Figure 3 This is a simplified acquisition circuit model diagram of the signal source reverse connection test solution provided by an embodiment of the present invention;

[0059] Figure 4 This is an implementation scheme for swapping the forward and reverse connections of a signal source provided by an embodiment of the present invention;

[0060] Figure 5 is a schematic diagram of a sample rack measuring device provided by an embodiment of the present invention;

[0061] Figure 6 This is a comparison diagram of complex resistivity measurement data of a limestone sample before and after correction provided by an application example of the present invention. DETAILED DESCRIPTION

[0062] The present invention will be described in further detail below with reference to the accompanying drawings.

[0063] Combined with attachment Figures 1-6 In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of this application.

[0064] To address the challenges of the existing technology, the present invention provides a method for correcting complex resistivity data of rock and mineral samples. This method utilizes two circuit design schemes: one for positive and one for negative signal source connection. By integrating test data from these two schemes, the method corrects the complex resistivity data of the rock sample. The invention is described in detail below with reference to the accompanying figures.

[0065] Rock complex resistivity data measurement is an effective means to study the internal structure of rock and ore, mineral composition and fluid chemical properties. However, during the complex resistivity test, especially in high frequency, the measurement results are affected by the instrument internal distributed capacitance, measurement device contact impedance and electrode polarization. In order to describe the true polarization characteristics of the sample, higher requirements are put forward for the test instrument and the measurement device. Especially in the high frequency part (>1kHz), the distributed capacitance of the internal acquisition channel of the instrument will cause significant phase error, so that the high frequency data must be calibrated before use. In addition to the internal circuit design and material selection of the instrument, the design of the measurement device is also very important. The measurement electrode will produce polarization phenomenon at low frequency, there is electromagnetic coupling interference between the measurement lines, and the contact impedance caused by the structure design all challenge the accuracy of the measurement results. Based on this, the application provides a rock and ore sample complex resistivity data correction method, which can improve the accuracy of the sample complex resistivity measurement and restore the frequency spectrum response characteristics of the rock sample.

[0066] The signal source positive circuit design scheme is as shown in Figure 2 Four acquisition channels (201, 202, 203, 204) are designed, and there is a distributed capacitance C generated by the leakage current of the amplifier (205) on the channel. Due to the limitation of circuit design and material selection of electronic elements, the distributed capacitance C is usually between 10pF-100pF, which produces obvious phase shift at high frequency (>1kHz); the sampling resistance Rs (206) is on the side of the excitation signal source (207), and the current first flows through the test sample Zx (208); due to the influence of the parasitic capacitance (about 1pF) inside the sampling resistance, its real impedance value should be Zs.

[0067] The relationship between the actual impedance Zx of the sample and the measured value Zm1 of the instrument positive circuit form is:

[0068]

[0069] Zx is the actual impedance of the measured sample; Zm1 is the impedance value obtained by measuring and calculating in the form of the instrument positive circuit; Rs is the resistance value of the sampling resistance; Zs is the actual impedance value of the sampling resistance; C is the distributed capacitance on the acquisition channel; ω is the angular frequency; i is the imaginary unit.

[0070] When the sampling resistance Rs is small (≤1kΩ), the influence of the internal parasitic capacitance is ignored, and the relationship between the actual impedance Zx and the measured value Zm1 becomes:

[0071]

[0072] Zx is the actual impedance of the measured sample; Zm1 is the impedance value obtained by measuring and calculating in the form of the instrument positive circuit; Rs is the resistance value of the sampling resistance; C is the distributed capacitance on the acquisition channel; |Zm1| and |Zm1| and φm1 represent the amplitude and phase of impedance Zm1 respectively; ω is the angular frequency; i is the imaginary unit.

[0073] When the signal source positive connection circuit form is used for measurement, the impedance measurement error is mainly reflected in the phase and is only related to the value of the sampling resistor Rs and is irrelevant to the impedance characteristics of the measured sample; when the sampling resistor Rs is small, the correction form is simple and fast, which is the currently widely used correction scheme. However, with the increase of the sampling resistor value, the impedance measurement error will be rapidly expanded, the correction form becomes complex, and the influence of the parasitic capacitance of the sampling resistor itself will also be enhanced; for the test object such as rock sample, the impedance of dense rock can reach 100 MΩ, if a small sampling resistor is used for testing, the voltage division on both sides of the sampling resistor is small, which leads to the decrease of the impedance test result precision; therefore, the present application provides five kinds of sampling resistors with different resistance values of 100 Ω, 1 kΩ, 10 kΩ, 100 kΩ and 1 MΩ, the optimal sampling resistor is adaptively selected according to the sample impedance value by using the impedance matching formula, and the distributed capacitance of the collection channel and the internal parasitic capacitance of the sampling resistor are corrected in combination with the signal source reverse connection circuit form.

[0074] The signal source reverse connection circuit design scheme is as shown in Figure 3 The four collection channels are represented by 301, 302, 303 and 304 respectively, the amplifier on the four collection channels is represented by 305, the sampling resistor Rs is represented by 306, the excitation signal source in the rock sample test process is represented by 307, and the measured sample Zx is represented by 308.

[0075] The signal source reverse connection circuit design scheme is obtained by changing the signal source access direction of the signal source positive connection circuit design scheme, at this time, the sampling resistor Rs (306) is in front of the excitation signal source (307).

[0076] The relationship between the actual impedance Zx of the sample and the measured value Zm2 of the signal source reverse connection circuit design scheme is as follows:

[0077]

[0078] Zx is the actual impedance of the measured sample; Zm2 is the impedance value obtained by measuring and calculating in the instrument reverse connection circuit form; Rs is the resistance value of the sampling resistor; Zs is the actual impedance value of the sampling resistor; C is the distributed capacitance on the collection channel; ω is the angular frequency; i is the imaginary unit.

[0079] When the impedance amplitude |Zm2| is small (≤1 kΩ), the relationship between the actual impedance Zx and the measured value Zm2 is changed to:

[0080]

[0081] Zx is the actual impedance of the measured sample; Zm2 is the impedance value obtained by measuring and calculating in the instrument reverse connection circuit form; Zs is the actual impedance value of the sampling resistor; C is the distributed capacitance on the collection channel; |Zm2| and respectively represent the amplitude and phase of the impedance Zm2; ω is the angular frequency; i is the imaginary unit.

[0082] Therefore, taking the 1kΩ resistance on the correction plate as the measured resistance, and selecting the default 1kΩ sampling resistance, the acquisition channel distribution capacitance C can be calculated:

[0083]

[0084] C is the acquisition channel distribution capacitance; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained when the signal source is measured in the reverse connection mode at 100kHz; Rs is the resistance value of the sampling resistance; f100k=100kHz is the highest frequency of the test.

[0085] By the test results Zm2 of different resistance models on the correction plate, the actual impedance Zs of different sampling resistances can be further calculated:

[0086]

[0087] Zs is the actual impedance of the sampling resistance; Zm2 is the impedance of the correction plate with different resistance models in the reverse connection circuit form; Rs is the resistance value of the sampling resistance; ω is the angular frequency; C is the distribution capacitance on the acquisition channel; i is the imaginary unit.

[0088] The signal source positive and negative connection interchange adopts an embodiment as shown in Figure 4 , when the two switches are simultaneously up-dial, the signal source access mode is the positive connection method, and when the two switches are simultaneously down-dial, the signal source access mode is the reverse connection method, wherein 401 is the measured sample Zx, 402 is the sampling resistance Rs, 403 is the excitation signal source, 404 is the switch for controlling the positive and negative connection of the signal source, the positive connection method when the switches are simultaneously up-dial, and the reverse connection method when the switches are simultaneously down-dial;

[0089] In combination with the two test schemes of the positive and negative connection of the signal source, the present application provides a rock and ore sample complex resistivity data correction method, as shown in Figure 1 , comprising the following steps:

[0090] S101: obtaining the original impedance data of the rock and ore sample as target data by using the positive connection circuit of the signal source;

[0091] Specifically, the positive connection circuit form of the signal source is used; the rock and ore sample is measured twice at a frequency of 1Hz, and the default sampling resistance 1kΩ is adopted; the error is calculated according to the two measurement results, and when the error is less than or equal to 1%, the average value of the two measurement results is calculated and saved; when the error is greater than 1%, the above steps are returned to re-measure twice the data;

[0092] According to the test impedance value Zm1(1Hz) of the rock sample at 1Hz, the optimal sampling resistance Rs matching therewith is calculated; if the calculated resistance value is greater than 1MΩ, 1MΩ sampling resistance is selected; if the calculated resistance value is less than 100Ω, 100Ω sampling resistance is selected;

[0093] Sampling resistance value matching formula:

[0094]

[0095] Rs is the sampling resistance to be selected, and Zm1(1Hz) is the impedance value of the rock sample at 1Hz;

[0096] The optimal sampling resistance Rs is selected, the frequency range and the number of frequency points to be tested are selected according to requirements, the maximum frequency range of the complex resistivity correction method is 0.001Hz-100kHz; the sweep measurement is sequentially performed at different frequencies from high frequency to low frequency, and the impedance value Zm1 of the rock sample under the signal source positive connection circuit form is obtained, which is taken as the target data for correction.

[0097] S102: Obtain impedance correction parameters by using the signal source reverse connection circuit;

[0098] Specifically, the signal source access direction of the test equipment is adjusted to the reverse connection form, impedance measurement is performed twice on the 1kΩ resistance on the correction board at a frequency of 100kHz, and the default sampling resistance 1kΩ is used for testing; the error is calculated according to the two measurement results, when the error is less than or equal to 1%, the average value of the two measurement results is obtained as Zm2(100kHz) and is saved; when the error is greater than 1%, the two data measurements are performed again;

[0099] According to the acquisition channel distributed capacitance calculation formula, the four-channel distributed capacitance C is obtained.

[0100] Acquisition channel distributed capacitance calculation formula:

[0101]

[0102] C is the acquisition channel distributed capacitance; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained by using the signal source reverse connection measurement method at 100kHz; Rs is the sampling resistance value; f100k=100kHz is the highest frequency of the test.

[0103] According to the signal source reverse connection circuit form, the impedance of the sampling resistance on the correction board is tested, and the sampling resistance selected by the test equipment is the optimal sampling resistance Rs; the test frequency is selected to be 100kHz to 0.001Hz, and the measured impedance value Zm2 in the reverse connection circuit form is recorded.

[0104] According to the actual impedance calculation formula of the sampling resistor, the actual impedance Zs of the sampling resistor is obtained;

[0105] The actual impedance calculation formula of the sampling resistor is:

[0106]

[0107] Zs is the actual impedance of the sampling resistor; Zm2 is the optimal sampling resistor measurement impedance in the reverse circuit form; Rs is the optimal sampling resistor resistance value; ω is the angular frequency; C is the distributed capacitance on the acquisition channel; and i is the imaginary unit.

[0108] S103: According to the signal source positive and negative connection correction method, the corrected complex resistivity data is obtained by using the original impedance data and the impedance correction parameter;

[0109] Specifically, according to the complex resistivity data correction method, the impedance value Zm1 of the test sample obtained by the signal source positive connection measurement mode, i.e., the target data, the optimal sampling resistor measurement impedance value Zm2 in the reverse circuit form, and the optimal sampling resistor Rs and its actual impedance value Zs are used for rock and mineral impedance data correction.

[0110] The rock and mineral sample complex resistivity correction method is:

[0111]

[0112] Zx is the corrected rock sample actual impedance; Zm1 is the target data before correction; Zm2 is the optimal sampling resistor measurement impedance in the reverse circuit form; Zs is the actual impedance of the sampling resistor; Rs is the sampling resistor resistance value; |Zm1|, |Zm2|, |Zs| and |Zm1|, |Zm2|, |Zs| and |Zx| respectively represent the amplitude and phase of the impedances Zm1, Zm2 and Zs; and i is the imaginary unit.

[0113] The corrected rock and mineral sample impedance data result is converted into impedance amplitude |Zx| and phase According to the sample size, the impedance amplitude is converted into complex resistivity amplitude ρx according to the resistance law, and the complex resistivity phase is still

[0114] In order to further illustrate the scheme, the application also provides an application example of the rock and mineral sample impedance data correction method in the limestone sample test, which is described as follows:

[0115] In this experiment, a limestone sample is used as the experimental sample. The limestone comes from the karst landform area in Yunnan Province of China, and is mainly composed of calcite (main component is calcium carbonate, CaCO3). The internal pore development is good, and does not contain metal minerals and other substances causing strong polarization effect.

[0116] The test equipment firstly adopts the signal source positive connection form to test the impedance data Zm1 of the sample as target data. During the test, the limestone sample needs to be prepared before the test according to the test requirements. The rock sample is cut to ensure that the surface of the rock and mineral sample is smooth and regular in shape, and the rock sample is in good contact with the sample holder. Due to the length limitation of the sample holder, the size of the rock sample should be controlled below 12 cm (length) * 4 cm (radius). After cutting, the rock sample generally needs to be soaked in a solvent for more than 24 h to ensure that the internal pores of the rock sample are completely filled with the solvent. The filling solvent is usually water or sodium chloride solution. The treated rock sample is clamped in the sample holder. After the test equipment is connected with the sample holder, the software controls the equipment to collect the impedance data of the rock sample at 1 Hz. At this time, the selected default sampling resistance is 1 kΩ. According to the test impedance value Zm1 (1 Hz) of the rock and mineral sample at 1 Hz, the optimal sampling resistance Rs matching the impedance value is calculated. If the calculated resistance value is greater than 1 MΩ, the 1 MΩ sampling resistance is selected. If the calculated resistance value is less than 100 Ω, the 100 Ω sampling resistance is selected. In the signal source positive connection form, the optimal sampling resistance is used to collect data at any frequency point in the frequency range of 0.001 Hz-100 kHz, and the data collection result Zm1 is recorded as the target data. Further, the correction parameters C (acquisition channel distributed capacitance) and Zs (actual impedance of sampling resistance) needed in the data correction process are measured by using the signal source reverse connection circuit form. The impedance of the 1 kΩ resistor on the correction plate is measured at 100 kHz to obtain Zm2 (100 kHz), and the default sampling resistance 1 kΩ is used for testing. The value of C is obtained according to the calculation formula of the acquisition channel distributed capacitance in the reverse connection circuit form. The impedance of the optimal sampling resistance on the correction plate is tested by using the signal source reverse connection circuit form, the test frequency is selected as 100 kHz to 0.001 Hz, the measured impedance value Zm2 in the reverse connection circuit form is recorded, and the actual impedance of the sampling resistance is calculated by using the formula to obtain Zs. The rock sample impedance data is corrected by using the complex resistivity data correction method according to the target data in the signal source positive connection circuit form, the measured Zm2 and the calculated correction parameters C (acquisition channel distributed capacitance) and Zs (actual impedance of sampling resistance) in the signal source reverse connection form. And the corrected rock and mineral sample impedance data result is converted into impedance amplitude |Zx| and phase According to the sample size, the impedance is converted into complex resistivity amplitude ρx and complex resistivity phase As Figure 6As shown, this limestone sample exhibits low resistivity and low polarization characteristics. Its well-developed pores result in low resistivity, but it lacks metallic mineral conductors that could cause significant polarization effects. Interfacial polarization effects are present only at high frequencies. Correction effectively restores the sample's true response characteristics. The pre-correction phase error is primarily present at high frequencies (>1kHz), reaching 42mrad at 100kHz. Therefore, correction is necessary for high-frequency test data.

[0117] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps of the complex resistivity data correction of the rock and mineral samples in the above embodiments. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, all the steps of the complex resistivity data correction of the rock and mineral samples in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0118] The rock sample impedance test at 1Hz is measured and controlled in the form of a positive circuit with a signal source, and the optimal sampling resistance Rs of the rock sample is calculated based on the impedance matching algorithm;

[0119] Measure and control the rock sample impedance test at different frequencies in the form of a signal source positive circuit and save the test results Zm1, i.e., target data;

[0120] The 1kΩ impedance test of the correction board at 1Hz is measured and controlled in the form of a reverse-connected signal source circuit, and the four-channel distributed capacitance C is calculated according to the calculation formula of the distributed capacitance of the acquisition channel;

[0121] Measure and control the impedance test of the optimal sampling resistor Rs in the form of a reverse-connected signal source circuit and save the test result Zm2, and calculate the actual impedance value Zs of the optimal sampling resistor;

[0122] The complex resistivity data correction method is used to correct rock and ore impedance data based on target data Zm1, the impedance value Zm2 measured by the optimal sampling resistor in the reverse circuit form, and the actual impedance value Zs calculated by the optimal sampling resistor.

[0123] A device for measuring the impedance of a rock or ore sample, set up for the above-mentioned sample, mainly includes a power supply electrode (501), a measuring electrode (502), a holder (503), and a sample holder container (504); the power supply electrode is made of a planar copper alloy material to provide a stable power supply current; the measuring electrode is an AgCl point reference electrode to prevent the influence of the electrode's own polarization on the measurement result. The holder mainly adopts a knob fixing scheme. After clamping the rock sample, the screw button is tightened to fix the rock sample to prevent the rock sample from falling off during the test; the interior of the sample holder container is filled with a saturated copper sulfate solution to reduce the mixed impedance between the power supply electrode and the receiving electrode.

[0124] The above describes the present application and its embodiments, which are not limited. The actual structure is not limited to the above. In general, if a person skilled in the art is inspired by the above, without departing from the spirit of the present application, similar structural modes and embodiments can be designed without creativity, and all of them should belong to the protection scope of the present application.

Claims

1. A method for correcting complex resistivity data of rock and mineral samples, characterized by: The method includes correcting the broadband complex resistivity data of the rock sample according to two circuit design schemes of positive and negative connection of the signal source. The impedance data correction method of the rock and ore sample includes:

1. Use the signal source to connect the circuit to obtain the original impedance data of the rock and ore sample as the target data; 2. Obtain impedance correction parameters using the signal source reverse circuit; 3. Using the original impedance data and the impedance correction parameters, obtain corrected complex resistivity data according to the signal source forward and reverse connection correction method; Among them, Zx is the actual impedance of the sample under test, Zm1 is the impedance value obtained by the instrument using the signal source positive connection measurement method, Zm2 is the impedance value obtained by the instrument using the signal source reverse connection measurement method, Zs is the actual impedance of the sampling resistor, |Zm1|, |Zm2|, |Zs| and They represent the amplitude and phase of impedances Zm1, Zm2, and Zs respectively, i is the imaginary unit, and Rs is the resistance of the sampling resistor.

2. The method for correcting complex resistivity data of a rock or ore sample according to claim 1, characterized in that: The signal source has two acquisition circuit design schemes, one for positive connection and the other for reverse connection: the signal source positive connection circuit design scheme designs the acquisition circuit into four acquisition channels (201, 202, 203, 204), a distributed capacitance C generated by the leakage current of the amplifier (205) exists on the channel, the sampling resistor Rs (206) is located at the end of the signal source, and its internal parasitic capacitance makes its actual impedance value become Zs, and the current first flows through the test sample Zx (208); The signal source reverse connection circuit design scheme is obtained by changing the signal source connection direction of the signal source forward connection circuit design scheme, and at this time, the sampling resistor Rs (306) is at the front end of the signal source.

3. The method for correcting complex resistivity data of a rock or ore sample according to claim 2, characterized in that: Calculate the relationship between the sample impedance Zx and the measured impedance value Zm, specifically including: A. The actual impedance Zx of the signal source positive connection circuit design sample is: Where: Zx is the actual impedance of the sample under test; Zm1 is the impedance value calculated by measuring the instrument in the positive circuit form; Rs is the resistance of the sampling resistor; Zs is the actual impedance of the sampling resistor; ω is the angular frequency; i is the imaginary unit; C is the distributed capacitance; B. The actual impedance Zx of the signal source reverse connection circuit design sample is: Where: Zx is the actual impedance of the sample under test, Zm1 is the impedance value calculated by the instrument measurement, Rs is the resistance of the sampling resistor, Zs is the actual impedance of the sampling resistor, ω is the angular frequency; i is the imaginary unit.

4. The method for correcting complex resistivity data of a rock or ore sample according to claim 1, wherein: The original impedance data of the rock and ore sample is obtained as the target data by using the signal source positive circuit, specifically including: A. Clamp the rock sample in the middle of the sample holder. After fixing it, connect the test equipment to the sample holder via a BNC triaxial measuring cable, and adjust the instrument host data measurement mode to the signal source positive connection measurement mode; B. Determine the optimal sampling resistor Rs required for the test based on the sampling resistor value matching method; C. Adjust the instrument sampling resistance to the optimal sampling resistance Rs. Select the test frequency range and frequency points according to requirements. The frequency range achieved by the complex resistivity correction method is 0.001Hz-100kHz. Perform sweep frequency measurements at different frequencies from high to low frequency in sequence to obtain the impedance value Zm1 of the rock and ore sample in the form of a positive circuit with a signal source, which is used as the target data for correction.

5. The method for correcting complex resistivity data of a rock or ore sample according to claim 4, characterized in that: The sampling resistor value matching method is used to determine the optimal sampling resistor Rs. The matching method is as follows: A. Using the default sampling resistance of 1kΩ, perform two impedance measurements on the rock and mineral sample at a frequency of 1Hz. Calculate the error based on the two measurement results. If the error is less than or equal to 1%, average the two measurement results and save them. If the error is greater than 1%, return to the above steps and perform two more data measurements. B. Calculate the optimal sampling resistor Rs based on the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz. If the calculated resistance is greater than 1MΩ, select a 1MΩ sampling resistor. If the calculated resistance is less than 100Ω, select a 100Ω sampling resistor. Sampling resistor resistance matching formula: Rs is the sampling resistor that needs to be selected, and Zm1(1Hz) is the rock sample impedance value at 1Hz.

6. The method for correcting complex resistivity data of a rock or ore sample according to claim 1, characterized in that: The impedance correction parameters are obtained by using the signal source reverse circuit, including: A. Adjust the test equipment's signal source connection direction to reverse polarity. Use a BNC triaxial measurement cable to connect the test equipment to the calibration board. The calibration board is equipped with five resistance models: 100Ω, 1kΩ, 10kΩ, 100kΩ, and 1MΩ. These five resistance models are consistent with the sampling resistor models inside the instrument. B. According to the calculation method of the distributed capacitance of the acquisition channel of the reverse circuit, the distributed capacitance C of the four acquisition channels is obtained; C. Test the impedance of the sampling resistor on the calibration board according to the reverse connection circuit of the signal source. At the same time, the sampling resistor selected by the test equipment is the optimal sampling resistor Rs. The test frequency is selected from 100kHz to 0.001Hz. Record the measured impedance value Zm2 in the reverse connection circuit. D. Obtain the actual impedance Zs of the sampling resistor according to the actual impedance calculation method of the sampling resistor.

7. The method for correcting complex resistivity data of a rock or ore sample according to claim 6, characterized in that: The distributed capacitance calculation method of the reverse connection circuit acquisition channel obtains the distributed capacitance C of the four acquisition channels, and the calculation method is as follows: A. Perform two impedance measurements on the 1kΩ resistor on the calibration board at 100kHz, using the default sampling resistor of 1kΩ. Calculate the error based on the two measurement results. If the error is less than or equal to 1%, average the two measurement results to obtain Zm2 (100kHz) and save the result. If the error is greater than 1%, perform two more measurements. B. Calculate the distributed capacitance C of the four acquisition channels according to the calculation formula of the distributed capacitance of the acquisition channels C is the distributed capacitance of the acquisition channel; is the phase of the impedance value Zm2(100kHz) obtained at 100kHz using the signal source reverse connection measurement method; Rs is the resistance of the sampling resistor; f100k=100kHz, which is the highest frequency tested.

8. The method for correcting complex resistivity data of a rock or mineral sample according to claim 6, wherein: The actual impedance calculation method of the sampling resistor is used to obtain the actual impedance Zs of the sampling resistor. The calculation method is as follows: Zs is the actual impedance of the sampling resistor; Zm2 is the impedance value obtained by the instrument using the signal source reverse connection measurement method; Rs is the optimal sampling resistor value; ω is the angular frequency; C is the distributed capacitance on the acquisition channel; and i is the imaginary unit.

9. The method for correcting complex resistivity data of a rock or ore sample according to claim 1, characterized in that: Using the original impedance data and the impedance correction parameters, and according to the signal source forward and reverse connection correction method, the corrected complex resistivity data is obtained, specifically including: A. Using the complex resistivity data correction method, the rock and ore impedance data is corrected based on the impedance value Zm1 of the test sample obtained by the signal source forward connection measurement method, that is, the target data, the impedance value Zm2 measured by the optimal sampling resistor in the reverse connection circuit form, and the optimal sampling resistor Rs and its actual impedance value Zs; Complex resistivity correction method for rock and ore samples: Zx is the actual impedance of the sample under test, Zm1 is the impedance value obtained by the instrument using the signal source positive connection measurement method, Zm2 is the impedance value obtained by the instrument using the signal source reverse connection measurement method, Zs is the actual impedance of the sampling resistor, |Zm1|, |Zm2|, |Zs| and Represent the amplitude and phase of impedance Zm1, Zm2, and Zs respectively, i is the imaginary unit, and Rs is the resistance of the sampling resistor; B. Convert the corrected rock and mineral sample impedance data into impedance amplitude |Zx| and phase According to the sample size, the impedance amplitude is converted into the complex resistivity amplitude ρx according to the resistance law, and the complex resistivity phase is still 10. An apparatus for measuring impedance of a rock or mineral sample using the calibration method according to any one of claims 1 to 9, characterized in that: It mainly includes a power supply electrode (501), a measuring electrode (502), a fixer (503), and a sample rack container (504); The power supply electrode (501) is made of a planar copper alloy material to provide a stable power supply current; The measuring electrode (502) adopts an AgCl point reference electrode to avoid the influence of the electrode's own polarization on the measurement result; The fixture (503) mainly adopts a knob fixing scheme. After clamping the rock sample, the knob is tightened to fix the rock sample to prevent the rock sample from falling off during the test. The sample holder container (504) is filled with a saturated copper sulfate solution to reduce the cross-resistance between the power supply electrode and the receiving electrode.

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