Method for correcting complex resistivity data of rock ore sample and measuring device thereof

Abstract

The invention discloses a rock ore complex resistivity measurement data correction method, which depends on two different acquisition circuit design schemes and is realized through positive and negative connection and interchange of a signal source. The method comprises the following steps: acquiring original impedance data of a rock ore sample as target data by using a signal source positive connection circuit; acquiring an impedance correction parameter by using the signal source reverse connection circuit; and obtaining corrected complex resistivity data by using the original impedance data and the impedance correction parameter according to the signal source positive and negative connection correction method. According to the method, interference of distributed capacitance of an acquisition channel and stray capacitance of a sampling resistor in test equipment can be suppressed, and high-precision measurement of rock and ore complex resistivity data in a 0.001 Hz-100 kHz broadband range is realized.

Description

Technical Field

[0001] The invention relates to the technical field of rock physics investigation and geophysical exploration, and in particular to a complex resistivity data correction method for rock and ore samples and a measuring device thereof. Background Art

[0002] Laboratory specimen testing is helpful for studying the relationship between rock and mineral physical parameters and geophysical field data, and is the basis for building geological geophysical models. Rock complex resistivity data measurement is an effective means to study the internal structure of rocks and minerals, mineral composition and fluid chemical properties. It is a geophysical method that describes the polarization intensity of rocks by testing the spectrum response characteristics of different samples under the application of an external electric field. Complex resistivity data includes two pieces of information, the real part and the imaginary part. The real part reflects the flow capacity of the conductive charge inside the sample, and the imaginary part is related to the accumulation of polarized charges inside and on the surface of the sample. Due to the strong polarization (IP) effect of metal minerals under an external electric field, complex resistivity measurement of samples is often used in mineral exploration and development, and the application frequency is generally below 1kHz. With the gradual improvement of test methods and theories, complex resistivity measurement has been widely used in engineering environmental surveys, hydrological surveys, medical engineering, plant pest control and other fields, and the measurement frequency has also expanded from traditional kHz to hundreds of kHz.

[0003] The polarization effect of a sample can reveal the relationship between its physical properties and the characteristics of the material and structure. This polarization effect is sometimes very weak. For example, in some non-mineralized sedimentary rock samples, the phase change is only a few millivolts, and the traditional measurement system can no longer monitor effective information. In order to describe the true polarization characteristics of the sample, high requirements are placed on the test instrument and the measuring device. Especially in the high-frequency part (>1kHz), many studies have confirmed that the distributed capacitance of the internal acquisition channel of the instrument will cause significant phase errors, so that 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 electrode will produce polarization at low frequencies, the electromagnetic coupling interference between the measuring lines, and the contact impedance caused by the structural design all pose challenges to the accuracy of the measurement results. Therefore, it is necessary to analyze the error of the overall complex resistivity measurement system.

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

[0005] The technical problem to be solved by the present invention is, in view of the deficiencies raised in the above-mentioned background technology, to provide a method for correcting the complex resistivity data of rock and mineral samples and a measuring device thereof, which realizes two circuit design schemes based on positive and negative connection of a signal source, and corrects the complex resistivity data of the rock sample by fusing the test data of the two test schemes.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is: a complex resistivity data correction method for rock and ore samples is characterized in that: it includes correcting the wide-band complex resistivity data of the rock sample according to two circuit design schemes of positive and negative connection of the signal source, and the impedance data correction method of the rock and ore sample includes:

[0007] 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;

[0008] 2. Obtain impedance correction parameters using the signal source reverse circuit;

[0009] 3. Using the original impedance data and the impedance correction parameters, the corrected complex resistivity data is obtained according to the signal source forward and reverse connection correction method;

[0010]

[0011] 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, and i is an imaginary unit.

[0012] Furthermore, the signal source has two acquisition circuit design schemes, positive connection and reverse connection: the signal source positive connection circuit design scheme designs the acquisition circuit into four acquisition channels (201, 202, 203, 204), and there is a distributed capacitance C generated by the leakage current of the amplifier (205) on the channel, and the sampling resistor Rs (206) is at the end of the signal source. Due to its internal parasitic capacitance, its real impedance value becomes Zs, and the current first flows through the test sample Zx (208);

[0013] 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.

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

[0015] A. The actual impedance Zx of the signal source positive connection circuit design sample is:

[0016]

[0017] Where: Zx is the actual impedance of the sample under test; Zm1 is the impedance value calculated by the instrument in the form of a positive circuit; 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;

[0018] B. The actual impedance Zx of the signal source reverse connection circuit design sample is:

[0019]

[0020] Where: Zx is the actual impedance of the sample under test, Zm1 is the impedance value calculated by the instrument, Rs is the resistance value of the sampling resistor, Zs is the actual impedance of the sampling resistor, ω is the angular frequency; i is the imaginary unit.

[0021] Furthermore, the original impedance data of the rock and ore sample is obtained as the target data by using the signal source positive circuit, which specifically includes:

[0022] A. Clamp the rock sample in the middle of the sample holder, fix it, connect the test equipment and the sample holder through the BNC triaxial measurement line, and adjust the instrument host data measurement mode to the signal source positive connection measurement form;

[0023] B. Determine the optimal sampling resistor Rs required for the test according to the sampling resistor value matching method;

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

[0025] Furthermore, the sampling resistor value matching method determines the optimal sampling resistor Rs, and the matching method is as follows:

[0026] A. Use the default sampling resistance of 1kΩ to measure the impedance of the rock sample twice at a frequency of 1Hz. Calculate the error based on the two measurement results. When the error is less than or equal to 1%, average the two measurement results and save them. When the error is greater than 1%, return to the above steps and re-measure the data twice.

[0027] B. According to the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz, calculate the corresponding optimal sampling resistor Rs; if the calculated resistance value is greater than 1MΩ, select a 1MΩ sampling resistor; if the calculated resistance value is less than 100Ω, select a 100Ω sampling resistor;

[0028] Sampling resistor 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 access direction of the test equipment signal source to the reverse connection form, and use the BNC triaxial measurement line to connect the test equipment and the calibration board. The calibration board is equipped with five resistance models of 100Ω, 1kΩ, 10kΩ, 100kΩ, and 1MΩ, which are consistent with the sampling resistance model inside the instrument;

[0033] B. According to the calculation method of the distributed capacitance of the acquisition channel of the reverse connection 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 impedance value Zm2 measured in the reverse connection circuit.

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

[0036] Furthermore, 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:

[0037] A. Perform impedance measurement twice at 100kHz for the 1kΩ resistor on the calibration board, using the default sampling resistor of 1kΩ for testing; calculate the error based on the two measurement results. When the error is less than or equal to 1%, average the two measurement results to obtain Zm2 (100kHz) and save it; when the error is greater than 1%, re-measure the data twice;

[0038] B. Calculate the distributed capacitance C of the four acquisition channels according to the calculation formula of the distributed capacitance of the acquisition channels

[0039]

[0040] C is the distributed capacitance of the acquisition channel; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained when the signal source is reversely connected at 100kHz; Rs is the resistance value of the sampling resistor; f100k=100kHz, which is the highest frequency tested.

[0041] Furthermore, the actual impedance calculation method of the sampling resistor 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 optimal sampling resistor measurement impedance in the reverse circuit form; Rs is the optimal sampling resistor value; ω is the angular frequency; C is the distributed capacitance on the acquisition channel; i is the imaginary unit.

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

[0045] A. Using 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 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 are used to correct the rock and ore impedance data;

[0046] Complex resistivity correction method for rock and ore samples:

[0047]

[0048] Zx is the actual impedance of the rock sample after correction; 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 resistance value of the sampling resistor; |Zm1|, |Zm2|, |Zs| and Respectively represent the amplitude and phase of impedance Zm1, Zm2, and Zs; i is an imaginary unit;

[0049] B. Convert the corrected rock and ore 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

[0050] Further, it mainly includes a power supply electrode, a measuring electrode, a fixer, and a sample holder container;

[0051] The power supply electrode is made of planar copper alloy material to provide a stable power supply current;

[0052] The measuring electrode adopts AgCl point reference electrode to avoid the influence of electrode self polarization on the measuring result;

[0053] The fixture mainly adopts a knob fixing solution. 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 a saturated copper sulfate solution to reduce the cross-resistance between the power supply electrode and the receiving electrode.

[0055] After adopting the above method, the present invention has the following advantages: a method for correcting complex resistivity data of rock and mineral samples. The original impedance data of the rock and mineral samples is obtained as target data using a signal source positive connection circuit, and impedance correction parameters are obtained using a signal source reverse connection circuit. The original impedance data and the impedance correction parameters are used to obtain corrected complex resistivity data according to the signal source positive and reverse connection correction method. Specifically, through the above operation steps, the present invention can effectively eliminate the measurement errors caused by factors such as the distributed capacitance of the acquisition channel and the parasitic capacitance of the sampling resistor itself, and combined with the sample rack design scheme, the influence of the device effect on the test results is reduced, and the measurement accuracy of the complex resistivity data of the rock and mineral samples is improved. At the same time, it has the advantages of high data accuracy, wide application range, and simple operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flow chart of a method for correcting complex resistivity data of rock and ore samples provided by an embodiment of the present invention;

[0057] Figure 2It 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 It 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 The embodiment of the present invention provides a signal source forward and reverse connection interchange implementation scheme;

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

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

[0062] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0063] Combined with Figure 1-6 In order to make those skilled in the art 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 them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] In view of the problems existing in the prior art, the present invention provides a method for correcting complex resistivity data of rock and ore samples. The method is related to two circuit design schemes of positive and negative connection of the signal source, and the correction of complex resistivity data of the rock sample is performed by integrating the test data of the two test schemes. The invention is described in detail below with reference to the accompanying drawings.

[0065] Rock complex resistivity data measurement is an effective means to study the internal structure of rocks and minerals, mineral composition and fluid chemical properties. However, during the complex resistivity test, especially in high-frequency conditions, the measurement results are affected by the internal distributed capacitance of the instrument, the contact impedance of the measuring device and the polarization of the electrode. In order to describe the true polarization characteristics of the sample, high requirements are placed on the test instrument and the measuring device. Especially in the high-frequency part (>1kHz), the distributed capacitance of the acquisition channel inside the instrument will cause significant phase errors, so that 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 electrode will produce polarization at low frequencies, there will be electromagnetic coupling interference between the measuring lines, and the contact impedance caused by the structural design will challenge the accuracy of the measurement results. Based on this, the present application provides a correction method for the complex resistivity data of rock and mineral samples, which can improve the accuracy of sample complex resistivity measurement and restore the spectral response characteristics of the rock sample itself.

[0066] The signal source positive connection circuit design scheme is as follows Figure 2 As shown, four acquisition channels (201, 202, 203, 204) are designed. There is a distributed capacitance C on the channel caused by the leakage current of the amplifier (205). Due to the limitations of circuit design and the materials of electronic components, the distributed capacitance C is usually between 10pF and 100pF, which produces an obvious phase shift at high frequencies (>1kHz); the sampling resistor Rs (206) is at the end 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 resistor, its actual impedance value should be Zs.

[0067] The relationship between the actual impedance Zx and the measured value Zm1 of the signal source positive connection circuit design sample is:

[0068]

[0069] Zx is the actual impedance of the sample under test; Zm1 is the impedance value calculated by measuring the instrument in the form of a positive circuit; Rs is the resistance of the sampling resistor; Zs is the actual impedance value of the sampling resistor; 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), ignoring the influence of its internal parasitic capacitance, the relationship between the actual impedance Zx and the measured value Zm1 becomes:

[0071]

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

[0073] When the signal source is measured in the positive connection circuit form, the impedance measurement error is mainly reflected in the phase, and is only related to the value of the sampling resistor Rs, and has nothing to do with the impedance characteristics of the sample being measured; when the sampling resistor Rs is small, the correction form is simple and fast, and it is the correction scheme currently commonly used. However, as the resistance of the sampling resistor increases, the impedance measurement error will expand rapidly, the correction form becomes complicated, and the influence of the parasitic capacitance of the sampling resistor itself will also increase; for test objects such as rock samples, the impedance of dense rocks can reach 100MΩ. If a small sampling resistor is used for testing, the voltage division on both sides of the sampling resistor is small, resulting in a decrease in the accuracy of the impedance test result; therefore, the present invention provides five different resistance sampling resistors of 100Ω, 1kΩ, 10kΩ, 100kΩ, and 1MΩ. The optimal sampling resistor is adaptively selected using the impedance matching formula according to the sample impedance value, and the distributed capacitance of the acquisition 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 follows Figure 3 As shown, 301, 302, 303, 304 represent four acquisition channels respectively, 305 represents the amplifiers on the four acquisition channels, 306 is the sampling resistor Rs, 307 is the excitation signal source during the rock sample testing process, and 308 is the sample Zx to be tested;

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

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

[0077]

[0078] Zx is the actual impedance of the sample under test; Zm2 is the impedance value calculated by measuring the reverse circuit of the instrument; Rs is the resistance of the sampling resistor; Zs is the actual impedance value of the sampling resistor; C is the distributed capacitance on the acquisition channel; ω is the angular frequency; i is the imaginary unit.

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

[0080]

[0081] Zx is the actual impedance of the sample under test; Zm2 is the impedance value calculated by measuring the reverse circuit of the instrument; Zs is the actual impedance value of the sampling resistor; C is the distributed capacitance on the acquisition channel; |Zm2| and They represent the amplitude and phase of impedance Zm2 respectively; ω is the angular frequency; i is the imaginary unit.

[0082] Therefore, the 1kΩ resistor on the calibration board is used as the measured resistor, and the sampling resistor selects the default 1kΩ sampling resistor, and the distributed capacitance C of the acquisition channel can be calculated:

[0083]

[0084] C is the distributed capacitance of the acquisition channel; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained when the signal source is reversely connected at 100kHz; Rs is the resistance value of the sampling resistor; f100k=100kHz, which is the highest frequency tested.

[0085] By correcting the test results Zm2 of different resistance models on the board, the actual impedance Zs of different sampling resistors can be further calculated:

[0086]

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

[0088] The signal source is connected in reverse order. Figure 4 In the embodiment shown, when the two switches are simultaneously turned up, the signal source access method is the positive connection method, and when the two switches are simultaneously turned down, the signal source access method is the reverse connection method, wherein 401 is the sample Zx to be tested, 402 is the sampling resistor Rs, 403 is the excitation signal source, and 404 is the switch for controlling the positive and reverse connection of the signal source. When the switches are simultaneously turned up, it is the positive connection method, and when they are simultaneously turned down, it is the reverse connection method;

[0089] Combining the two test schemes of forward and reverse connection of the signal source, the present invention provides a method for correcting complex resistivity data of rock and ore samples, such as Figure 1 As shown, the following steps are included:

[0090] S101: using a signal source to positively connect the circuit to obtain the original impedance data of the rock and ore sample as the target data;

[0091] Specifically, a signal source positive connection circuit form is used; impedance measurements are performed twice on the rock and ore sample at a frequency of 1 Hz, and a default sampling resistance of 1 kΩ is used; the error is calculated based on the two measurement results, and when the error is less than or equal to 1%, the two measurement results are averaged and saved; when the error is greater than 1%, the above steps are returned to perform two more data measurements;

[0092] According to the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz, calculate the optimal sampling resistor Rs that matches it; if the calculated resistance value is greater than 1MΩ, select a 1MΩ sampling resistor; if the calculated resistance value is less than 100Ω, select a 100Ω sampling resistor;

[0093] Sampling resistor value matching formula:

[0094]

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

[0096] Select the calculated optimal sampling resistance Rs, select the test frequency range and frequency points according to the needs, the maximum frequency range achieved by the complex resistivity correction method is 0.001Hz-100kHz; perform sweep frequency measurements at different frequencies from high frequency to low frequency in turn, and obtain the impedance value Zm1 of the rock and ore sample in the form of a positive circuit of the signal source, which is used as the target data for correction.

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

[0098] Specifically, adjust the access direction of the signal source of the test equipment to the reverse connection form, perform two impedance measurements on the 1kΩ resistor on the correction board at a frequency of 100kHz, and use the default sampling resistor of 1kΩ for testing; calculate the error based on the two measurement results, and when the error is less than or equal to 1%, calculate the average of the two measurement results to obtain Zm2 (100kHz) and save it; when the error is greater than 1%, re-measure the data twice;

[0099] According to the calculation formula of the distributed capacitance of the acquisition channel of the reverse connection circuit, the four-channel distributed capacitance C is obtained;

[0100] The calculation formula of the distributed capacitance of the acquisition channel is:

[0101]

[0102] C is the distributed capacitance of the acquisition channel; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained when the signal source is reversely connected at 100kHz; Rs is the resistance of the sampling resistor; f100k=100kHz, which is the highest frequency tested.

[0103] The impedance of the sampling resistor on the calibration board is tested according to the reverse connection circuit form 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. The impedance value Zm2 measured in the reverse connection circuit form is recorded;

[0104] Obtaining the actual impedance Zs of the sampling resistor according to the actual impedance calculation formula of the sampling resistor;

[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 value; ω is the angular frequency; C is the distributed capacitance on the acquisition channel; i is the imaginary unit.

[0108] S103: using the original impedance data and the impedance correction parameters, and obtaining corrected complex resistivity data according to the signal source forward and reverse connection correction method;

[0109] Specifically, the complex resistivity data correction method is used to correct the rock and ore impedance data according to the impedance value Zm1 of the test sample obtained by the signal source forward connection measurement method, that is, 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;

[0110] Complex resistivity correction method for rock and ore samples:

[0111]

[0112] Zx is the actual impedance of the rock sample after correction; 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 resistance value of the sampling resistor; |Zm1|, |Zm2|, |Zs| and Respectively represent the amplitude and phase of impedance Zm1, Zm2, and Zs; i is an imaginary unit;

[0113] Convert the corrected rock and ore 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

[0114] In order to further illustrate the present solution, the present application also provides an application example of a correction method for rock and ore sample impedance data in limestone sample testing, which is specifically described as follows:

[0115] This experiment uses a limestone sample as the experimental sample. The limestone comes from the karst landform area of ​​Yunnan Province, China. It is mainly composed of calcite (the main component is calcium carbonate, CaCO3), has well-developed internal pores, and does not contain metal minerals or other substances that cause strong polarization effects.

[0116] For the test equipment, the impedance data Zm1 of the sample is first tested in the form of positive connection of the signal source as the target data; during the test process, the limestone sample needs to be prepared before the test according to the test requirements, and the rock sample is cut to ensure that the surface of the rock and ore sample is flat and smooth, and the shape is regular, so as to facilitate good direct contact between the rock sample and the sample rack; due to the length limit of the sample rack, the rock sample specifications should be controlled below 12cm (length) * 4cm (radius); after the rock sample is cut, it is generally necessary to soak in the solvent for more than 24 hours to ensure that the internal pores of the rock sample are completely filled with the solvent, and the filling solvent is mostly clean water or sodium chloride solution; the processed rock sample is clamped in the sample rack, and when the test equipment is connected to the sample rack, the software controls the equipment to collect the rock sample impedance data at a frequency of 1Hz, and the default sampling resistance of 1kΩ is selected at this time. According to the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz, calculate the optimal sampling resistor Rs that matches it; if the calculated resistance value is greater than 1MΩ, select a 1MΩ sampling resistor; if the calculated resistance value is less than 100Ω, select a 100Ω sampling resistor; in the form of positive connection of the signal source, use the optimal sampling resistor to collect data at any frequency point in the frequency range of 0.001Hz-100kHz, and record the data collection result Zm1 as the target data; further, use the form of reverse connection of the signal source circuit to measure the correction parameters C (distributed capacitance of the acquisition channel) and Zs (actual impedance of the sampling resistor) required in the data correction process; measure the impedance of the 1kΩ resistor on the correction board at a frequency of 100kHz to obtain Zm2(100kHz), The default sampling resistor of 1kΩ is used for testing; the C value is obtained according to the calculation formula of the distributed capacitance of the acquisition channel in the reverse circuit form; the impedance of the optimal sampling resistor on the correction board is tested according to the reverse circuit form of the signal source, the test frequency is selected to be 100kHz to 0.001Hz, the measured impedance value Zm2 in the reverse circuit form is recorded, and Zs is obtained by using the actual impedance calculation formula of the sampling resistor; the complex resistivity data correction method is used to correct the rock sample impedance data according to the target data in the positive circuit form of the signal source and the measured Zm2 in the reverse circuit form of the signal source and the calculated correction parameters C (distributed capacitance of the acquisition channel) and Zs (actual impedance of the sampling resistor); and the corrected rock and ore sample impedance data results are converted into impedance amplitude |Zx| and phase According to the sample size and the resistance law, the impedance is converted into complex resistivity amplitude ρx and complex resistivity phase like Figure 6As shown in the figure, the limestone sample exhibits low resistance and low polarization characteristics. Its pores are well developed, resulting in low resistivity. However, it does not contain metal mineral conductors that can cause obvious polarization effects, and only has interface polarization effects at high frequencies. After correction, the true response characteristics of the sample are effectively restored. The phase error before correction is mainly reflected in the high-frequency part (>1kHz), which can reach 42mrad at 100kHz. Therefore, it is necessary to correct the high-frequency test data.

[0117] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps in the complex resistivity data correction of the rock and ore 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 in the complex resistivity data correction of the rock and ore 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 signal source positive circuit, and the optimal sampling resistance Rs of the rock sample is calculated according to the impedance matching algorithm;

[0119] The impedance test of rock samples at different frequencies in the form of a positive circuit connected to the signal source is measured and controlled and the test result Zm1, i.e., the target data, is saved;

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

[0121] The impedance test of the optimal sampling resistor Rs in the form of a signal source reverse connection circuit is measured and controlled and the test result Zm2 is saved, and the actual impedance value Zs of the optimal sampling resistor is calculated;

[0122] The complex resistivity data correction method is used to correct rock and ore impedance data based on the 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 sample mainly includes a power supply electrode (501), a measuring electrode (502), a fixture (503), and a sample rack container (504); the power supply electrode adopts a planar copper alloy material to provide a stable power supply current; the measuring electrode adopts an AgCl point reference electrode to avoid the influence of the electrode's own polarization on the measurement result. The fixture 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 sample rack container is filled with a saturated copper sulfate solution to reduce the impurity between the power supply electrode and the receiving electrode.

[0124] The present invention and its implementation methods are described above, and such description is not restrictive, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by it, and does not deviate from the purpose of the invention, and does not creatively design a structure and implementation method similar to the technical solution, they should all fall within the protection scope of the present invention.

Claims

1. A method for correcting complex resistivity data of rock and ore samples, characterized in that: The method comprises 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 comprises:

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, the corrected complex resistivity data is obtained 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, and i is an imaginary unit.

2. The complex resistivity data correction method for rock and ore samples according to claim 1, characterized in that: The signal source has two acquisition circuit design schemes, positive connection and reverse connection: the signal source positive connection circuit design scheme designs the acquisition circuit into four acquisition channels (201, 202, 203, 204), and there is a distributed capacitance C generated by the leakage current of the amplifier (205) on the channel. The sampling resistor Rs (206) is at the end of the signal source. Due to the parasitic capacitance inside it, its real impedance value becomes 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 complex resistivity data correction method for rock and ore samples according to claim 2, characterized in that: The relationship between the sample impedance Zx and the measured impedance value Zm can be calculated, 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 the instrument in the form of a positive circuit; 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; 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, Rs is the resistance value 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 complex resistivity data correction method for rock and ore samples according to claim 1, characterized in that: The original impedance data of the rock and ore samples is obtained as the target data by using the signal source positive circuit, which includes: A. Clamp the rock sample in the middle of the sample holder, fix it, connect the test equipment and the sample holder through the BNC triaxial measurement line, and adjust the instrument host data measurement mode to the signal source positive connection measurement form; B. Determine the optimal sampling resistor Rs required for the test according to 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 the needs, the maximum frequency range achieved by the complex resistivity correction method is 0.001Hz-100kHz; perform sweep frequency measurements at different frequencies from high frequency to low frequency in turn, and obtain the impedance value Zm1 of the rock and ore sample in the form of a positive circuit of the signal source, which is used as the target data for correction.

5. The complex resistivity data correction method for rock and ore samples according to claim 4, characterized in that: The sampling resistor value matching method determines the optimal sampling resistor Rs, and the matching method is as follows: A. Use the default sampling resistance of 1kΩ to measure the impedance of the rock sample twice at a frequency of 1Hz. Calculate the error based on the two measurement results. When the error is less than or equal to 1%, average the two measurement results and save them. When the error is greater than 1%, return to the above steps and re-measure the data twice. B. According to the test impedance value Zm1(1Hz) of the rock and ore sample at 1Hz, calculate the corresponding optimal sampling resistor Rs; if the calculated resistance value is greater than 1MΩ, select a 1MΩ sampling resistor; if the calculated resistance value is less than 100Ω, select a 100Ω sampling resistor; Sampling resistor value 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 complex resistivity data correction method for rock and ore samples according to claim 1, characterized in that: The impedance correction parameters are obtained by using the signal source reverse connection circuit, including: A. Adjust the access direction of the test equipment signal source to the reverse connection form, and use the BNC triaxial measurement line to connect the test equipment and the calibration board. The calibration board is equipped with five resistance models of 100Ω, 1kΩ, 10kΩ, 100kΩ, and 1MΩ, which are consistent with the sampling resistance model inside the instrument; B. According to the calculation method of the distributed capacitance of the acquisition channel of the reverse connection 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 impedance value Zm2 measured in the reverse connection circuit. D. The actual impedance Zs of the sampling resistor is obtained according to the actual impedance calculation method of the sampling resistor.

7. The complex resistivity data correction method for rock and ore samples 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 impedance measurement twice at 100kHz for the 1kΩ resistor on the calibration board, using the default sampling resistor of 1kΩ for testing; calculate the error based on the two measurement results. When the error is less than or equal to 1%, average the two measurement results to obtain Zm2 (100kHz) and save it; when the error is greater than 1%, re-measure the data twice; 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; (100kHz) is the phase of the impedance value Zm2(100kHz) obtained when the signal source is reversely connected at 100kHz; Rs is the resistance value of the sampling resistor; f100k=100kHz, which is the highest frequency tested.

8. The complex resistivity data correction method for rock and ore samples according to claim 6, characterized in that: The actual impedance calculation method of the sampling resistor obtains the actual impedance Zs of the sampling resistor, and the calculation method is as follows: 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 value; ω is the angular frequency; C is the distributed capacitance on the acquisition channel; i is the imaginary unit.

9. The complex resistivity data correction method for rock and ore samples 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 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 are used to correct the rock and ore impedance data; Complex resistivity correction method for rock and ore samples: Zx is the actual impedance of the rock sample after correction; 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 resistance value of the sampling resistor; |Zm1|, |Zm2|, |Zs| and Respectively represent the amplitude and phase of impedance Zm1, Zm2, and Zs; i is an imaginary unit; B. Convert the corrected rock and ore 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. The device for measuring impedance of a rock or ore sample according to claim 4, 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) uses 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 solution. After the rock sample is clamped, 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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