Method and device for measuring dielectric parameters of a drilling fluid

Abstract

This invention relates to the field of oil and gas drilling engineering technology, specifically a method and apparatus for measuring the dielectric parameters of drilling fluids. The former includes the following steps: adding the drilling fluid to be tested into a reaction vessel and setting the reaction vessel's operating conditions; setting a frequency range and applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid to be tested, thereby obtaining the amplitude and phase of the complex impedance of the drilling fluid under the corresponding AC electric field conditions. This invention solves the technical problem that existing drilling fluid dielectric parameter measurement devices cannot meet the requirements for simulating complex downhole operating conditions. It provides a method for measuring the dielectric parameters of various drilling fluids under high temperature, high pressure, and gas-bearing conditions with a wide frequency range. This invention can simultaneously simulate complex operating conditions such as high temperatures up to 200℃, high pressures of 80MPa, and adjustable gas content of 0-30%. The experimental conditions closely resemble the real downhole environment, and the obtained data are more valuable for reference. It can meet the measurement needs of various drilling fluids, from highly conductive to highly insulating.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling engineering technology, and is a method and device for measuring the dielectric parameters of drilling fluids. Background Technology

[0002] The dielectric properties of drilling fluids (mud) are closely related to their composition and operating conditions. During drilling, formation fluid intrusion (such as well kick) can cause significant changes in parameters such as the dielectric constant and conductivity of the mud, which can be used to monitor fluctuations in gas content, oil content, and solids content in the mud. Therefore, accurate measurement of mud dielectric parameters is of great significance for laboratory evaluation of mud performance and calibration of measurement-while-drilling (LWD / MWD) tools.

[0003] However, existing technologies have many shortcomings in simulating complex downhole conditions and ensuring measurement accuracy. First, the high-temperature and high-pressure environment downhole places stringent demands on measuring devices, while traditional dielectric measuring instruments mostly operate at ambient temperature and pressure, failing to accurately reflect the dielectric response of drilling mud downhole. Second, for multiphase drilling fluids containing gas, their high resistivity and strong dielectric heterogeneity pose significant challenges to measurement, making it difficult for existing devices to simultaneously achieve accurate measurements over a wide range of conditions, including highly conductive water-based drilling mud and highly insulating gas-containing drilling mud.

[0004] A more prominent problem is the severe impact of electromagnetic interference (EMI) on precision dielectric measurements. In laboratory environments, various electronic devices, motors, and high-frequency signals can couple into the weak dielectric measurement signals through conduction or radiation. Especially when testing high-impedance oil-based or aerated slurries, the useful signal current is extremely weak and easily drowned out by noise, leading to data distortion. Existing experimental systems often integrate internal interference sources such as electric heaters and electric stirrers, and their grounding and shielding designs are often inadequate, easily forming ground loops, further deteriorating the signal-to-noise ratio and severely affecting the accuracy and stability of measurements.

[0005] In summary, there is an urgent need to develop a drilling fluid dielectric parameter measurement system and method that can simulate complex working conditions such as high temperature, high pressure, and multiphase fluids in wells, while possessing strong electromagnetic interference suppression capabilities, in order to overcome the limitations of existing technologies. Summary of the Invention

[0006] This invention provides a method and apparatus for measuring the dielectric parameters of drilling fluids, overcoming the shortcomings of the prior art and effectively solving the problems of low accuracy and stability in existing drilling fluid dielectric parameter measuring devices.

[0007] One of the technical solutions of the present invention is achieved through the following measures: a method for measuring the dielectric parameters of drilling fluid, comprising the following steps:

[0008] The drilling fluid to be tested is added into the reactor, and the reactor is set to the operating conditions.

[0009] By setting a frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to the drilling fluid under test, and the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions are obtained.

[0010] By converting the complex impedance at different frequency points, the complex permittivity of the drilling fluid under the corresponding AC electric field condition is obtained, and the corresponding dielectric loss tangent is calculated to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and the virtual part Dielectric loss tangent ;

[0011] The operating parameters are correlated with the dielectric parameters at each different frequency point to generate a dielectric spectrum of dielectric parameters as the operating parameters change, where the operating parameters include temperature, pressure, and gas content.

[0012] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions:

[0013] The above-mentioned frequency range is calibrated before applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test, including:

[0014] Add the standard medium into a standard vessel identical to the reaction vessel;

[0015] Within a set frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to a standard medium to obtain the amplitude and phase of the response signal of the standard medium under the corresponding AC electric field conditions.

[0016] The baseline zero, gain, and phase data are obtained by averaging the amplitude and phase of multiple response signals.

[0017] Based on the baseline zero point, gain, and phase data, compensation parameters are calculated, including zero point offset, gain error, and phase error.

[0018] Within the aforementioned frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to the drilling fluid under test to obtain the amplitude and phase of the complex impedance of the drilling fluid under the corresponding AC electric field conditions, including:

[0019] A 1Hz-100kHz sinusoidal AC excitation voltage signal is output through a wideband signal source;

[0020] A sinusoidal AC excitation voltage signal of 1Hz-100kHz is applied to the drilling fluid under test by the guard electrode assembly;

[0021] The voltage and current signals corresponding to each frequency point of the drilling fluid under test are collected, and the amplitude and phase of the complex impedance are calculated.

[0022] The amplitude and phase of the complex impedance of the drilling fluid under test are corrected based on the compensation parameters under the corresponding AC electric field conditions.

[0023] The above also includes the identification of abnormal data, setting a data fluctuation threshold, comparing the dielectric parameters obtained after multiple measurements of the drilling fluid under different operating conditions with the set data fluctuation threshold, and marking the corresponding operating parameters when the dielectric parameters change abnormally.

[0024] The second technical solution of the present invention is achieved through the following measures: the drilling fluid dielectric parameter measuring device includes:

[0025] The reactor is used to add the drilling fluid to be tested and to set the operating conditions of the reactor.

[0026] The measurement and control unit includes a wideband impedance measurement module, a data processing module, and a guard electrode assembly located on the inner right side of the reactor and capable of applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid to be measured.

[0027] The wideband impedance measurement module sets the frequency range and applies sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test through the guard electrode assembly to obtain the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions.

[0028] The data processing module, combining the geometric parameters of the guard electrode assembly and the electrode equivalent model, converts all complex impedances to obtain the complex permittivity of the drilling fluid under the corresponding AC electric field conditions, and calculates the corresponding dielectric loss tangent to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and the virtual part Dielectric loss tangent ;

[0029] The plotting unit correlates the operating parameters with the dielectric parameters at each different frequency point to generate a dielectric spectrum showing the change of dielectric parameters with the operating parameters, including frequency, temperature, pressure, and gas content.

[0030] The following are further optimizations and / or improvements to the second technical solution of the above invention:

[0031] The aforementioned wideband impedance measurement module may include an adjustable frequency signal source and a lock-in amplifier detector;

[0032] The adjustable frequency signal source outputs sinusoidal AC excitation voltage signals at different frequency points within a set frequency range;

[0033] The lock-in amplifier detector collects the current and phase difference of the drilling fluid under test at each frequency point, and obtains the amplitude and phase of the complex impedance of the drilling fluid under test at each frequency point.

[0034] The above may also include a switching module, a reference error analysis module, a correction error analysis module, and a standard vessel with the same structure as the reaction vessel and storing standard media.

[0035] The switching module controls the switching of the wideband impedance measurement module to either a standard vessel or a reaction vessel.

[0036] The reference error analysis module obtains baseline zero, gain, and phase data based on the average amplitude and phase of multiple response signals. Based on the baseline zero, gain, and phase data, it calculates compensation parameters, including zero offset, gain error, and phase error.

[0037] The error correction analysis module corrects the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions based on the compensation parameters.

[0038] Both the lower right side of the aforementioned reactor and the lower right side of the standard reactor have a first mounting hole that connects internally and externally. A guard electrode assembly is installed in each of the first mounting holes. The lower left end of both the reactor and the standard reactor have a second mounting hole that connects vertically. A filter through-chamber connector is installed in each of the second mounting holes. A three-coaxial guard measurement cable is installed in the filter through-chamber connector. An adjustable frequency signal source is connected to a switching module. The switching module is connected to the guard electrode assembly on the inner right side of the reactor and the guard electrode assembly on the inner right side of the standard reactor, respectively. The guard electrode assembly on the inner right side of the reactor is connected to the three-coaxial guard measurement cable on the inner left side of the reactor. The guard electrode assembly on the inner right side of the standard reactor is connected to the three-coaxial guard measurement cable on the inner left side of the standard reactor. Both the three-coaxial guard measurement cable on the inner left side of the reactor and the three-coaxial guard measurement cable on the inner left side of the standard reactor are connected to a lock-in amplifier detector.

[0039] The aforementioned reactor may further include a pressurizing pump, a constant temperature heating mechanism, a stirring shaft, stirring blades, a first pneumatic drive mechanism, and a working condition control module. A pressurizing port is provided on the inner side of the upper part of the reactor. A gas injection pipeline is fixedly connected between the pressurizing port and the outlet of the pressurizing pump. A control valve is installed on the gas injection pipeline. A heating shell is provided on the outer side of the reactor. A closed heating chamber is formed between the inner side of the heating shell and the outer side of the reactor. An inlet and outlet with internal and external communication are provided at intervals on the outer side of the heating shell. The inlet and outlet of the heating shell are fixedly connected to the inlet and outlet of the constant temperature heating mechanism, respectively. A stirring shaft is provided on the inner side of the lower part of the reactor. Several stirring blades are evenly distributed circumferentially on the outer side of the upper part of the stirring shaft. The lower end of the stirring shaft is sealed and passes through the lower side of the reactor. A first pneumatic drive mechanism is installed at the lower end of the reactor. The upper end of the output shaft of the first pneumatic drive mechanism is drively connected to the lower end of the stirring shaft. The working condition control module is connected to the pressurizing pump, the constant temperature heating mechanism, and the first pneumatic drive mechanism, respectively.

[0040] The above may also include a fixed frame and a second pneumatic drive mechanism. A tilting shaft is rotatably mounted on the upper part of the fixed frame. The outer side of the middle part of the tilting shaft is fixedly mounted together with the lower end of the reactor. A second pneumatic drive mechanism is mounted on the side of the fixed frame. The output shaft of the second pneumatic drive mechanism is connected to the end of the tilting shaft. The second pneumatic drive mechanism is connected to the working condition control module.

[0041] The method and apparatus for measuring the dielectric parameters of drilling fluids of the present invention have the following advantages compared with the prior art:

[0042] 1. Strong resistance to electromagnetic interference: By eliminating major interference sources such as internal motors and electric heaters, and combining multiple measures such as Faraday cage shielding, transmission protection, filtering isolation and single-point grounding, the baseline noise is low, which significantly improves the signal-to-noise ratio and accuracy when measuring high-impedance samples.

[0043] 2. Comprehensive and realistic simulation of working conditions: The system can simultaneously simulate complex working conditions such as high temperature of up to 200℃, high pressure of 80MPa, and gas content adjustable from 0-30%. The experimental conditions are closer to the real downhole environment, and the data obtained are more valuable for reference.

[0044] 3. Wide measurement range and high accuracy: It adopts broadband impedance spectroscopy technology and high-sensitivity lock-in amplification detection, which can cover the measurement needs of various drilling fluids from high conductivity to high insulation. The calibration technology can effectively eliminate measurement data drift and ensure the long-term stability and comparability of measurement results.

[0045] 4. The compensation parameters are used to automatically correct the original measurement data when measuring the drilling fluid under test, realize real-time error correction, and automatically compensate for the influence of environmental temperature drift and device drift on the measurement results.

[0046] 5. Reliable structure and good safety: The electrode assembly adopts ceramic / PEEK encapsulation, which is resistant to high temperature, corrosion and has good insulation. Attached Figure Description

[0047] Appendix Figure 1 This is a schematic diagram of the front cross-sectional structure of the drilling fluid dielectric parameter measuring device of the present invention.

[0048] The codes in the attached diagram are as follows: 1 is the reaction vessel, 2 is the broadband impedance measurement module, 3 is the guard electrode assembly, 4 is the filter through-chamber connector, 5 is the triaxial guard measurement cable, 6 is the standard vessel, 7 is the pressurization pump, 8 is the constant temperature heating mechanism, 9 is the heating shell, 10 is the stirring shaft, 11 is the stirring blade, 12 is the first pneumatic drive mechanism, 13 is the operating condition control module, 14 is the fixed frame, 15 is the tilting shaft, and 16 is the second pneumatic drive mechanism. Detailed Implementation

[0049] The present invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of the present invention.

[0050] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0051] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0052] Example 1: As shown in the attached document Figure 1 As shown, the method for measuring the dielectric parameters of the drilling fluid includes the following steps:

[0053] The drilling fluid to be tested is added into reactor 1, and the operating conditions of reactor 1 are set.

[0054] By setting a frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to the drilling fluid under test, and the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions are obtained.

[0055] By converting the complex impedance at different frequency points, the complex permittivity of the drilling fluid under the corresponding AC electric field condition is obtained, and the corresponding dielectric loss tangent is calculated to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and Dielectric loss tangent ;

[0056] The operating parameters are correlated with the dielectric parameters at each different frequency point to generate a dielectric spectrum of dielectric parameters as the operating parameters change, where the operating parameters include temperature, pressure, and gas content.

[0057] The specific steps described above are as follows:

[0058] 1. Sample preparation and working condition setting: The drilling fluid to be tested (which can be water-based mud, oil-based mud, or foam mud with added gas) is injected into reactor 1. The reactor 1 is pressurized to the target pressure (0-80MPa). The drilling fluid to be tested is heated to the set temperature and kept constant. At the same time, gas is injected into the drilling fluid to be tested as needed to achieve the predetermined gas content. During the entire preparation process, the drilling fluid to be tested is stirred or reactor 1 is inverted to ensure that the temperature and pressure of the drilling fluid to be tested are uniform and stable, and the gas-liquid distribution is uniform.

[0059] 2. Wideband excitation and signal acquisition: A sinusoidal AC excitation voltage signal within a set frequency range can be applied to the drilling fluid under test through the guard electrode assembly 3. To ensure accurate detection of high impedance weak signals, lock-in amplification technology is used to simultaneously measure the amplitude and phase of the response current.

[0060] 3. Parameter Calculation: Convert the measured complex impedance data into the complex permittivity (real part). and the virtual part and the dielectric loss tangent;

[0061] The complex impedance is calculated using the following formula. :

[0062] ;

[0063] in For excitation voltage, For amplitude, The phase angle, The magnitude of the impedance, It is the exponential form of the complex number, where It is the imaginary unit. This represents a signal with a magnitude of 1 and a phase angle of . The complex unit vector, i.e. ;

[0064] The complex permittivity is calculated using the following formula. :

[0065] ;

[0066] in, Let be the real part of the complex permittivity. This represents the imaginary part of the complex permittivity. The imaginary unit, For complex impedance, The angular frequency of the excitation signal, in radians per second, is related to the frequency f as follows: , Vacuum capacitor, vacuum capacitor We obtain it from the following formula:

[0067] ;

[0068] in, is the dielectric constant of air, and K is the geometric electrode constant of the guard electrode assembly 3.

[0069] It should also be noted that if a sinusoidal AC excitation voltage signal within a set frequency range is applied to the drilling fluid under test via the guard electrode assembly 3, to ensure accurate detection of the high-impedance weak signal, lock-in amplification technology is used to simultaneously measure the amplitude and phase of the response current. Then, combined with the geometric parameters and equivalent model of the guard electrode assembly, the complex impedance is calculated to obtain the complex permittivity (real part) of the drilling fluid under AC electric field conditions. and the virtual part ).

[0070] 4. Spectrum Generation: The working condition parameters are mapped to dielectric parameters at different frequency points and stored. The calculation results are correlated with the corresponding working condition parameters such as temperature, pressure, and gas content to generate a multi-dimensional dielectric spectrum (plotting the two-dimensional relationship between frequency and dielectric parameters, or the three-dimensional relationship between frequency, temperature, and dielectric parameters, etc.). This allows for a direct analysis of the relationship between the dielectric properties of the drilling fluid (mud) under test and the downhole environment (frequency, temperature, pressure, gas content).

[0071] This invention provides a method for measuring the dielectric parameters of various drilling fluids under high temperature, high pressure, and gas-containing conditions. This invention can simultaneously simulate complex working conditions such as high temperature up to 200℃, high pressure of 80MPa, and adjustable gas content of 0-30%. The experimental conditions are closer to the real downhole environment, and the obtained data are more valuable for reference. It can meet the measurement needs of various drilling fluids from high conductivity to high insulation.

[0072] The above-mentioned methods for measuring the dielectric parameters of drilling fluids can be further optimized and / or improved according to actual needs:

[0073] Example 2: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, a frequency range is set, and calibration is performed before complex impedance measurements are conducted within this frequency range, including:

[0074] Add the standard medium into the same standard vessel 6 as reaction vessel 1;

[0075] Within a set frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to a standard medium to obtain the amplitude and phase of the response signal of the standard medium under the corresponding AC electric field conditions.

[0076] The baseline zero, gain, and phase data are obtained by averaging the amplitude and phase of multiple response signals.

[0077] Based on the baseline zero point, gain, and phase data, compensation parameters are calculated, including zero point offset, gain error, and phase error.

[0078] The standard medium is a vacuum, air, or a standard liquid with a known dielectric constant. The standard medium in the standard vessel 6 is first measured to calibrate the baseline zero point, phase, and gain. The calibration process can be performed before and after each measurement, automatically compensating for the effects of environmental temperature drift and device drift on the measurement results, ensuring the stability and accuracy of long-term measurements.

[0079] Before the formal measurement, the standard vessel 6 is calibrated. Zero bias and phase offset data at different frequency points of the standard medium are acquired and stored as calibration values. The gain and phase of the measurement are adjusted as needed to ensure that the system achieves the expected measurement accuracy under reference conditions. Calibration before performing complex impedance oscillation measurement within this frequency range can effectively eliminate system drift and ensure the long-term stability and comparability of the measurement results.

[0080] Example 3: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, a frequency range is set, and sinusoidal AC excitation voltage signals at different frequency points are applied to the drilling fluid under test. The amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions are obtained, including:

[0081] A 1Hz-100kHz sinusoidal AC excitation voltage signal is output through a wideband signal source;

[0082] A sinusoidal AC excitation voltage signal of 1Hz-100kHz is applied to the drilling fluid under test through the guard electrode assembly 3;

[0083] The voltage and current signals corresponding to each frequency point of the drilling fluid under test are collected, and the amplitude and phase of the complex impedance are calculated.

[0084] The amplitude and phase of the complex impedance of the drilling fluid under test are corrected based on the compensation parameters under the corresponding AC electric field conditions.

[0085] The compensation parameters are used to automatically correct the original measurement data when measuring the drilling fluid under test, realize real-time error correction, automatically compensate for the influence of environmental temperature drift and device drift on the measurement results, and ensure the stability and accuracy of long-term measurement.

[0086] Example 4: As attached Figure 1 As shown, the operating steps for measuring the dielectric properties of oil-based drilling fluids under high temperature and high pressure include:

[0087] 1. Inject the oil-based drilling fluid to be tested into reactor 1 and heat it to 150°C. Increase the pressure inside reactor 1 to 50MPa. During the heating and pressure stabilization process, intermittently stir the oil-based drilling fluid to be tested in reactor 1 to ensure that the temperature and pressure of the oil-based drilling fluid to be tested are uniform.

[0088] 2. After the operating conditions stabilize, add the standard medium into the standard vessel 6, which is the same as the reaction vessel 1. The operating parameters of the standard vessel 6 and the reaction vessel 1 are the same. In this embodiment, the standard medium is air. First, output a 1Hz-100kHz sinusoidal AC excitation voltage signal to the standard medium in the standard vessel 6, obtain the baseline error at the current temperature, and store it as calibration parameters.

[0089] 3. Then output a 1Hz-100kHz sinusoidal AC excitation voltage signal to the drilling fluid to be tested in the reactor 1 to obtain the current amplitude and phase of the oil-based drilling fluid to be tested.

[0090] 4. Collect raw data, first subtract the baseline error obtained during calibration, then calculate the complex dielectric constant of the oil-based drilling mud at 150℃ and 50MPa and plot the dielectric spectrum. The results show that, compared with normal temperature and pressure, the real part of the dielectric constant of the oil-based drilling mud under high temperature and high pressure is higher. There is a significant decrease, and the dielectric loss peak shifts to higher frequencies.

[0091] Example 5: When simulating the effect of gas intrusion on the dielectric properties of water-based drilling fluids, the operating steps include:

[0092] 1. Inject water-based drilling fluid into reactor 1 and heat and pressurize it to simulate downhole conditions of 80℃ and 20MPa. Slowly inject nitrogen into reactor 1 and control the injection amount to gradually increase the mud gas content from 0% to 15%. At each gas content point, stir the water-based drilling fluid for 30 seconds and then let it stand for 1 minute to make the bubbles evenly distributed.

[0093] 2. After each gas content (e.g., 0%, 5%, 10%, 15%) stabilizes, a calibration and measurement are performed. The process is the same as the calibration and measurement process in Example 4 (the standard medium is added to the standard vessel 6, which is the same as the reaction vessel 1. The operating parameters of the standard vessel 6 and the reaction vessel 1 are the same. First, the standard medium in the standard vessel 6 is measured in the frequency range of 1Hz-100kHz to obtain the baseline error at the current temperature and store it as calibration parameters. Then, the reaction vessel 1 is measured to obtain the current amplitude and phase of the oil-based drilling fluid to be tested).

[0094] 3. By comparing and analyzing the dielectric spectra corresponding to each gas content, the experimental results show that as the gas content increases, the real part of the equivalent dielectric constant of the drilling fluid increases. It decreases significantly, and relaxation phenomena caused by gas-liquid interface polarization appear in specific frequency bands.

[0095] Example 6: When measuring the dielectric parameters of mud under normal temperature and pressure, the operating steps include:

[0096] 1. Reactor 1 is used under normal pressure. Pour the prepared water-based / oil-based slurry into reactor 1, stir it pneumatically for 30-60 seconds to make it uniform, and let it stand for 1-2 minutes to remove large air bubbles.

[0097] 2. Add the standard medium into the same standard vessel 6 as the reaction vessel 1. The operating parameters of the standard vessel 6 and the reaction vessel 1 are the same. First, measure the standard medium in the standard vessel 6 in the frequency range of 1Hz-100kHz to obtain the baseline error at the current temperature and store it as calibration parameters for zero-point and amplitude-phase correction.

[0098] 3. Perform complex impedance measurements within the frequency range of 1Hz-100kHz and record the complex impedance. The amplitude and phase.

[0099] 4. Based on the measured complex impedance of the water-based / oil-based mud, the complex impedance is converted to obtain the complex permittivity of the water-based / oil-based mud under the corresponding AC electric field conditions. Furthermore, the dielectric loss tangent is calculated, and the complex permittivity (including the real part) is converted... and the virtual part The result of the dielectric loss tangent as a function of frequency is output as a dielectric spectrum and archived.

[0100] Example 7: When measuring the dielectric parameters of gas-bearing drilling fluid, the operating steps include:

[0101] 1. At room temperature or a set temperature, a certain amount of the gas to be tested (or foaming agent) is injected into the reactor 1 to form different gas content conditions; after stirring, the bubble size distribution and volume fraction can be repeated.

[0102] 2. Correct the zero point and amplitude / phase.

[0103] 3. Perform multiple complex impedance measurements on the gas (or foaming agent) under test within the frequency range of 1Hz-100kHz, following the cycle of "frequency sweep → short-time averaging → frequency sweep", to obtain the complex permittivity. The relationship with gas content and bubble size.

[0104] 4. By comparing the dielectric spectra of conventional mud and aerated mud, we provide an empirical fitting relationship between the peak position and amplitude variation of the dielectric loss tangent tanδ and the air content, which will facilitate subsequent on-site indication.

[0105] Example 8: When measuring dielectric parameters under temperature-pressure coupling conditions, the operating steps include:

[0106] 1. Heat reactor 1 to the target temperature (e.g., 120°C) at a ramp rate of 1–2°C / min, pressurize reactor 1 to the target pressure (e.g., 10–20 MPa), and monitor the pressure stability. After stabilizing under high temperature and high pressure, perform short-term pneumatic stirring to eliminate the temperature / concentration gradient.

[0107] 2. Similar to Example 4, perform calibration and measurement to obtain the real part of the complex permittivity. The imaginary part of the complex permittivity The response curves of the dielectric loss tangent tanδ as a function of temperature and pressure are displayed, and the mapping relationship between temperature, pressure and dielectric parameters is output.

[0108] Before injecting the drilling fluid to be tested into reactor 1, pretreatment is required to remove large particulate impurities and maintain fluid homogeneity. The drilling fluid sample is then injected into reactor 1 through a high-pressure, corrosion-resistant injection pipeline, ensuring that reactor 1 is leak-free.

[0109] Example 9: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, it also includes the identification of abnormal data, setting a data fluctuation threshold, comparing the dielectric parameters obtained after multiple measurements of the drilling fluid under different operating conditions with the set data fluctuation threshold, and marking the corresponding operating parameters when the dielectric parameters change abnormally.

[0110] Set a data fluctuation threshold. For example, a sudden increase in the dielectric constant at a certain frequency may correspond to a large amount of bubble precipitation. Automatically screen out abnormal points (such as instrument interference mutation points) and mark them. Output CSV, Excel and customized experimental report formats for easy subsequent analysis and archiving.

[0111] Example 10: As attached Figure 1 As shown, the device for measuring the dielectric parameters of the drilling fluid includes:

[0112] Reactor 1: The drilling fluid to be tested is added into reactor 1, and the operating conditions of reactor 1 are set.

[0113] The measurement and control unit includes a wideband impedance measurement module 2, a data processing module, and a guard electrode assembly 3, which is located on the inner right side of the reactor 1 and is capable of applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid to be measured.

[0114] The wideband impedance measurement module 2 sets the frequency range and applies sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test through the guard electrode assembly 3 to obtain the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions.

[0115] The data processing module, combining the geometric parameters of the guard electrode assembly 3 and the electrode equivalent model, converts all complex impedances to obtain the complex permittivity of the drilling fluid under the corresponding AC electric field conditions, and calculates the corresponding dielectric loss tangent to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and the virtual part Dielectric loss tangent ;

[0116] The plotting unit correlates the operating parameters with the dielectric parameters at each different frequency point to generate a dielectric spectrum showing the change of dielectric parameters with the operating parameters, including frequency, temperature, pressure, and gas content.

[0117] The reactor 1 serves as the main body for pressure bearing and electromagnetic shielding; the guard electrode assembly 3 is encapsulated with corrosion-resistant and high-insulation materials and is designed with guard electrodes to eliminate edge effects and leakage current; the measurement and control unit integrates a wideband impedance measurement module 2 and a data processing module to realize automated measurement.

[0118] In this embodiment, the reactor 1 is a high-temperature and high-pressure reactor used to contain the drilling fluid to be tested. It can withstand high pressure of 0-80MPa and high temperature environment of room temperature to 200℃. The reactor 1 is made of high-strength corrosion-resistant alloy steel. The internal pressure isolation can be achieved through high-temperature resistant seals, and the external metal grounding treatment is performed. All cavity connections (flanges, welding points) are electrically continuous to avoid electromagnetic leakage. The reactor 1 is equipped with a ceramic-encapsulated guard electrode assembly 3 as a dielectric sensing unit. The guard electrode assembly 3 adopts a coaxial electrode structure and includes a central emitting electrode, a ring measuring electrode, and a grounding electrode. The central emitting electrode, the ring measuring electrode, and the grounding electrode are encapsulated and isolated by a high dielectric strength PEEK insulation layer, which can provide electrical insulation and high-temperature corrosion protection, and also act as a dielectric barrier to reduce the influence of electrode polarization and leakage current, thus ensuring measurement accuracy.

[0119] The data processing module includes a high-speed ADC and an embedded processor (such as an STM32 microcontroller), which can calculate the complex permittivity (real part). and the virtual part Parameters such as dielectric loss tangent can be measured. As needed, the same sample can be repeatedly measured under different operating conditions. For example, transient changes in dielectric parameters can be continuously monitored at a fixed frequency, or measurements can be repeated after changing pressure / temperature. Abnormal changes are automatically identified based on set thresholds, and data under corresponding conditions is marked. The plotting unit is a host computer with pre-set graphics processing software.

[0120] This application can obtain the complex dielectric constant and loss angle data of drilling fluids over a wide frequency range, and output a complete dielectric spectrum by combining information such as temperature, pressure, and gas content. The experimental results can accurately reflect the electrical characteristics of different types of drilling fluids in simulated downhole environments, providing support for optimizing mud formulations and improving monitoring-while-drilling (MSWD) technology. This device can solve the technical problem that existing drilling fluid dielectric parameter measurement devices cannot meet the requirements for simulating complex downhole operating conditions.

[0121] The measuring device for the dielectric parameters of the drilling fluid can be further optimized and / or improved according to actual needs:

[0122] Example 11, as an optimization of the above examples, is as follows: Figure 1 As shown, the wideband impedance measurement module 2 includes an adjustable frequency signal source and a lock-in amplifier detector;

[0123] The adjustable frequency signal source outputs sinusoidal AC excitation voltage signals at different frequency points within a set frequency range;

[0124] The lock-in amplifier detector collects the current and phase difference of the drilling fluid under test at each frequency point, and obtains the amplitude and phase of the complex impedance of the drilling fluid under test at each frequency point.

[0125] The wideband impedance measurement module 2 employs AC impedance spectroscopy technology, incorporating an adjustable frequency signal source and a high-precision lock-in amplifier detector. The signal source outputs a sinusoidal AC excitation voltage signal within the range of 1Hz to 100kHz, which is applied between the ring measuring electrode and the grounding electrode of the guard electrode assembly 3, generating an AC electric field in the drilling fluid under test. The lock-in amplifier detector simultaneously measures the current and phase difference passing through the drilling fluid under test, acquiring the complex impedance value (amplitude and phase) of the drilling fluid under test at each frequency point. By employing wideband complex impedance measurement and lock-in amplifier detection technology, a complete mapping of the dielectric spectrum of the drilling fluid under test as environmental parameters change can be obtained.

[0126] To accommodate the diverse dielectric properties of different drilling fluids under test, the wideband impedance measurement module 2 is designed with multiple measurement ranges and adjustable excitation amplitude. By switching the reference resistance and adjusting the excitation voltage, it achieves accurate impedance measurement from a few ohms to hundreds of megohms, ensuring no distortion or saturation even with highly conductive and highly insulating drilling fluids. The data processing module filters and averages the data output from the phase-locked loop detection, and converts it into physical quantities such as the dielectric constant based on the calibration model.

[0127] Example 12: As an optimization of the above embodiments, as shown in the appendix Figure 1 As shown, it also includes a switching module, a reference error analysis module, a correction error analysis module, and a standard vessel 6 with the same structure as the reaction vessel 1 and storing standard media;

[0128] The switching module controls the switching of wideband impedance measurement module 2 to either standard vessel 6 or reaction vessel 1.

[0129] The reference error analysis module obtains baseline zero, gain, and phase data based on the average amplitude and phase of multiple response signals. Based on the baseline zero, gain, and phase data, it calculates compensation parameters, including zero offset, gain error, and phase error.

[0130] The error correction analysis module corrects the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions based on the compensation parameters.

[0131] To further ensure measurement accuracy, this device includes a switching module, a reference error analysis module, a correction error analysis module, and a standard vessel 6. The standard vessel 6 is structurally identical to the reaction vessel 1. It is filled with a standard medium with known dielectric properties (e.g., vacuum / air or a standard liquid with a known dielectric constant). The switching module allows the standard vessel 6 to be connected to the broadband impedance measurement module 2 for calibration. The switching module can be a relay or a solid-state switch.

[0132] During measurement, the standard vessel 6 is first measured under no-load conditions to calibrate the zero point, phase, and gain of the measuring device. Specifically: the air-filled standard vessel 6 measurement is used to correct for the stray capacitance effects of cables and electrodes, using the baseline capacitance as the zero-point offset calibration value; the built-in standard resistor and capacitor modules are used for phase and gain calibration (e.g., to match the measured loss angle of a known capacitor with the theoretical value, thereby correcting the phase error and amplitude ratio of the lock-in amplifier). The above closed-loop calibration process can be performed before and after each measurement, automatically compensating for the effects of ambient temperature drift and device drift on the measurement results, ensuring the stability and accuracy of long-term measurements.

[0133] Example 13: As an optimization of the above embodiments, as shown in the appendix Figure 1As shown, both the lower right side of reactor 1 and the lower right side of standard reactor 6 are provided with a first mounting hole that connects the inside and outside. A guard electrode assembly 3 is installed in the first mounting hole. Both the lower left end of reactor 1 and the lower left end of standard reactor 6 are provided with a second mounting hole that connects vertically. A filter through-chamber connector 4 is installed in the second mounting hole. A three-coaxial guard measurement cable 5 is installed in the filter through-chamber connector 4. An adjustable frequency signal source is connected to a switching module. The switching module is connected to the guard electrode assembly 3 on the inner right side of reactor 1 and the guard electrode assembly 3 on the inner right side of standard reactor 6. The guard electrode assembly 3 on the inner right side of reactor 1 is connected to the three-coaxial guard measurement cable 5 on the inner left side of reactor 1. The guard electrode assembly 3 on the inner right side of standard reactor 6 is connected to the three-coaxial guard measurement cable 5 on the inner left side of standard reactor 6. The three-coaxial guard measurement cable 5 on the inner left side of reactor 1 and the three-coaxial guard measurement cable 5 on the inner left side of standard reactor 6 are both connected to a lock-in amplifier detector.

[0134] The guard electrode assembly 3 is ceramic-encapsulated and includes a central emitting electrode, a ring measuring electrode, and a grounding electrode. The ring measuring electrode and grounding electrode are arranged around the central emitting electrode to form a coaxial structure, which can reduce edge effects. The filter penetration connector 4 contains a three-coaxial guard measuring cable 5. The filter penetration connector 4 and the three-coaxial guard measuring cable 5 form a signal extraction and shielding unit to build an anti-interference signal transmission channel. That is, the ring measuring electrode is connected to the three-coaxial guard measuring cable 5, so that the ring measuring electrode, the three-coaxial guard measuring cable 5, and the phase-locked amplifier detector are connected in sequence to collect the current and phase difference of the drilling fluid passing through each frequency point.

[0135] This device is designed with an electromagnetic interference-resistant signal connection scheme. The dielectric sensor leads use a triaxial shielded cable, i.e., a triaxial shielded cable with a shielding layer. The inner conductor is connected to the ring-shaped measuring electrode, and the inner shielding layer acts as the shielding electrode, maintaining the same potential as the ring-shaped measuring electrode. The outer shielding layer is grounded. This three-layer coaxial structure greatly reduces cable distributed capacitance leakage and environmental noise pickup, ensuring the transmission quality of high-impedance weak signals. In addition, the triaxial shielded measuring cable 5, which serves as the signal lead, passes through the vessel wall and connects to the phase-locked amplifier detector via a filter penetration connector 4, which acts as a shield. The filter penetration connector 4 has a built-in multi-stage low-pass filter network to filter and shield all wires entering the vessel, allowing only low-frequency measurement signals to pass through and cutting off high-frequency electromagnetic noise paths. All metal vessels, shielding layers, and grounding wires adopt a system-level star grounding strategy to converge to a single-point grounding point to avoid ground loop current interference. The entire reactor 1 and signal conditioning circuit are encapsulated in a Faraday cage shielding structure, physically isolating external electromagnetic fields and minimizing the impact of environmental electromagnetic interference on the measurement.

[0136] This device has strong EMI suppression capabilities and high sensitivity. Even when the gas content is low (<5%), it can clearly capture minute changes in the dielectric constant, providing reliable experimental evidence for early warning of minute gas intrusion based on dielectric parameters.

[0137] Example 14: Based on the drilling fluid dielectric parameter measuring device described in Examples 10 to 13, the specific method for measuring the drilling fluid dielectric parameter includes:

[0138] 1. Excitation signal generation and application: A sinusoidal AC excitation voltage signal (typical amplitude range 100mV~1V) is output through a broadband signal source; the sinusoidal AC excitation voltage signal is applied through the center transmitting electrode in the guard electrode assembly 3.

[0139] 2. Signal Transmission Path Design: The filter-through connector 4 is equipped with a three-coaxial guard measurement cable 5. The adjustable frequency signal source is connected to the switching module. The switching module is connected to the guard electrode assembly 3 on the inner right side of reactor 1 and the guard electrode assembly 3 on the inner right side of standard reactor 6. The guard electrode assembly 3 on the inner right side of reactor 1 is connected to the three-coaxial guard measurement cable 5 on the inner left side of reactor 1. The guard electrode assembly 3 on the inner right side of standard reactor 6 is connected to the three-coaxial guard measurement cable 5 on the inner left side of standard reactor 6. The left side of reactor 1... The inner three-coaxial protective measuring cable 5 and the inner left side of the standard vessel 6 are both connected to the phase-locked loop amplifier detector. The sinusoidal AC excitation voltage signal and the response current signal are transmitted through the three-coaxial protective cable. The inner conductor is connected to the measuring electrode, the middle protective layer is connected to the equipotential, and the outer shielding layer is grounded. The protective shielding cable shields common-mode noise, which can avoid the coupling of environmental electromagnetic signals. The through-chamber connector has a built-in multi-stage low-pass filter (cutoff frequency of about 1MHz or less) to block high-frequency interference signals from entering the measurement circuit.

[0140] 3. Response signal detection: The AC response current signal passing through the drilling fluid under test is synchronously detected using a lock-in amplifier; the signal amplitude and phase angle are collected to ensure that the data covers more than 85% of the frequency points and avoids blind spots; for high impedance samples (oil-based mud, gas-containing mud), low-noise current amplification and high-precision sampling technology are adopted to improve sensitivity, and the detection current range can reach the pA level.

[0141] 4. Data Processing and Storage: The acquired amplitude and phase data are processed using digital filtering and multiple sampling averaging methods to reduce the impact of random noise; environmental sensor measurements such as temperature, pressure, and gas content are mapped one-to-one with the dielectric parameters at each frequency point and stored; a multidimensional dataset is formed to facilitate the plotting of two-dimensional frequency-dielectric parameter relationships, or three-dimensional frequency-temperature-dielectric parameter relationships; the processed data is sent to the repository in real time for subsequent analysis.

[0142] 5. Dielectric spectrum plotting: Use graphics processing software to generate curves showing the changes in frequency versus the real and imaginary parts of the dielectric constant as a function of frequency; generate comparison charts of multiple curves under controlled variables such as temperature or pressure; analyze the characteristics of gas content changes and dielectric behavior in the tracer mud through spectrum analysis.

[0143] Example 15: As an optimization of the above embodiments, as shown in the appendix. Figure 1 As shown, the reactor 1 also includes a pressure pump 7, a constant temperature heating mechanism 8, a stirring shaft 10, stirring blades 11, a first pneumatic drive mechanism 12, and a working condition control module 13. A pressure port is provided on the inner side of the upper part of the reactor 1. A gas injection pipeline is fixedly connected between the pressure port and the outlet of the pressure pump 7. A control valve is installed on the gas injection pipeline. A heating shell 9 is provided on the outer side of the reactor 1. A closed heating chamber is formed between the inner side of the heating shell 9 and the outer side of the reactor 1. An inlet and outlet with internal and external communication are provided at intervals on the outer side of the heating shell 9. The inlet and outlet are fixedly connected to the inlet and outlet of the constant temperature heating mechanism 8, respectively. A stirring shaft 10 is provided on the inner side of the lower part of the reactor 1. Several stirring blades 11 are evenly distributed along the circumference on the outer side of the upper part of the stirring shaft 10. The lower end of the stirring shaft 10 is sealed and passes through the lower side of the reactor 1. A first pneumatic drive mechanism 12 is installed at the lower end of the reactor 1. The upper end of the output shaft of the first pneumatic drive mechanism 12 is connected to the lower end of the stirring shaft 10. The working condition control module 13 is connected to the pressure pump 7, the constant temperature heating mechanism 8 and the first pneumatic drive mechanism 12, respectively.

[0144] The first pneumatic drive mechanism 12 is a known technology, such as a pneumatic motor. Alternatively, it can be replaced by a known hydraulic motor. When the first pneumatic drive mechanism 12 is working, it can drive the stirring shaft 10 and the stirring blade 11 to rotate. The stirring blade 11 is made of corrosion-resistant materials (such as stainless steel or coated materials), thereby achieving fluid homogenization and state simulation of the drilling fluid sample to be tested within the reactor 1. Furthermore, it avoids electromagnetic interference generated by electrically driven equipment. The stirring speed and interval are set by the operating condition control module 13 to prevent uneven flow caused by continuous high-speed rotation. Periodic stirring is also implemented. The mixing scheme (e.g., 30 seconds of stirring + 90 seconds of static circulation); the constant temperature heating mechanism 8 is a known technology, such as an oil bath constant temperature heater, which serves as an external heat source and can provide a stable and interference-free heating environment. The medium filled inside the heating shell 9 is highly insulating and thermally conductive silicone oil or thermal oil, which indirectly heats the drilling fluid sample to be tested in the reactor 1, avoiding the installation of strong interference sources such as electric heating elements inside the reactor 1; the pressure pump 7 is a known hydraulic pressure pump. The pressure pump 7 can control the injected gas in the reactor 1 through a gas injection pipeline equipped with a mass flow meter, which is used to accurately set the pressure and gas content.

[0145] In this embodiment, the first pneumatic drive mechanism 12 is located at the bottom of the high-temperature and high-pressure reactor 1. During operation, it is used to stir the drilling fluid to be tested. The stirring blade 11 is made of corrosion-resistant material. The first pneumatic drive mechanism 12 is driven by compressed air to achieve sufficient stirring of the high-viscosity drilling fluid sample (high-viscosity mud) and the gas-containing drilling fluid sample (gas-containing mud). The first pneumatic drive mechanism 12 does not generate electromagnetic radiation during operation, thus avoiding the interference problems caused by traditional motor stirring. After the stirring blade 11 rotates, it can ensure that the components of the sample are uniformly mixed, prevent solid phase sedimentation or gas phase aggregation, thereby obtaining representative dielectric parameter measurement results.

[0146] The constant-temperature heating mechanism 8 is used to control the temperature of the reactor 1. Preferably, a constant-temperature oil bath is used, immersing the reactor 1 in a heating shell 9 filled with thermally conductive silicone oil. The oil bath heater uniformly heats the outer wall of the reactor 1, achieving stable heating and constant temperature control of the mud sample from room temperature to the target temperature. Oil bath heating offers advantages such as high heat capacity and temperature stability, avoiding the direct use of electric heating elements inside the reactor, thus eliminating the influence of internal heating resistance wires on dielectric measurements. An insulation layer is added to the outside of the heating shell 9 to ensure safe operation at high temperatures. Temperature fluctuations can be controlled within ±0.5℃ using sensors and a PID temperature controller. A temperature sensor (thermocouple or PT100) monitors the internal temperature of the reactor 1 online and feeds it back to the operating condition control module 13.

[0147] The pressurizing pump 7 is connected to the reactor 1 and is used to apply static pressure to the drilling fluid to be tested to simulate the downhole depth pressure environment. A high-pressure gas cylinder, pressure reducing valve, and mass flow controller are connected to the inlet of the pressurizing pump 7 to precisely inject a certain volume ratio of gas (such as nitrogen or air) into the drilling fluid sample to form foam mud with the required gas content. The injection volume is monitored in real time using a mass flow meter and a gas pressure sensor to precisely control the required gas content (0%–30%). By coordinating liquid pressurization and gas injection, a multiphase drilling fluid sample system ranging from single-phase liquid to multiphase drilling fluid with a gas content of up to 30% can be simulated. A safety relief valve and pressure sensor are installed on the injection pipeline, which can shut off the gas source and stabilize the pressure after the set pressure is reached. At this time, the electrical connection part with the reactor 1 is relatively stationary to avoid mechanical vibration and flow disturbance to the measurement during the pressurization process. After the pressure stabilizes, the measurement is started to obtain accurate dielectric parameter data.

[0148] The operating condition control module 13 connects to a temperature sensor, a pressure sensor, and a gas flow meter (all of which can be installed on the reactor 1 or on the pipeline) to realize real-time monitoring and closed-loop control of experimental temperature, pressure, and gas content. All measurement data and environmental parameters are transmitted to the host computer for real-time display and recording via a wired interface (such as an RS485 differential link).

[0149] The aforementioned components work together to form a complete high-temperature, high-pressure multiphase drilling fluid dielectric constant measurement system. In use, the drilling fluid to be tested is placed in the reaction vessel 1, and the constant-temperature heating mechanism 8 heats the fluid to the target temperature and stabilizes it. The pressure is then increased to the required pressure and gas content by the pressurization pump 7, followed by measurement and data acquisition. The entire system effectively suppresses internal and external electromagnetic interference through shielding and grounding design, ensuring that the measured dielectric parameters accurately reflect the intrinsic characteristics of the drilling mud under downhole conditions.

[0150] Example 15: As an optimization of the above embodiments, as shown in the appendix. Figure 1 As shown, it also includes a fixed frame 14 and a second pneumatic drive mechanism 16. A tilting shaft 15 is rotatably mounted on the upper part of the fixed frame 14. The outer side of the middle part of the tilting shaft 15 is fixedly mounted together with the lower end of the reactor 1. The second pneumatic drive mechanism 16 is mounted on the side of the fixed frame 14. The output shaft of the second pneumatic drive mechanism 16 is connected to the end of the tilting shaft 15. The second pneumatic drive mechanism 16 is connected to the working condition control module 13.

[0151] The second pneumatic drive mechanism 16 has the same structure as the first pneumatic drive mechanism 12. In order for the reactor 1 to rotate normally, slip rings are provided on the pipelines and lines. The second pneumatic drive mechanism 16 rotates the reactor 1 in a pneumatic manner to rotate the entire reactor 1 by a certain angle (such as 15-45°), simulating the floating of bubbles and the homogenization of multiphase distribution. The rotation action is slow and stable, avoiding mechanical vibration to induce electromagnetic interference, and realizing the homogenization of the drilling fluid sample to be tested in the reactor 1. The pneumatic drive mechanism can avoid generating electromagnetic interference from the motor. All metal parts are grounded to a single point through a star grounding strategy to avoid ground loop interference.

[0152] The fixed frame 14 and the second pneumatic drive mechanism 16 are used to support and manipulate the tilting of the reactor 1. The second pneumatic drive mechanism 16 uses pneumatic power instead of a motor (or hydraulic power) to achieve tilting or tilting of the reactor 1 without the use of electricity. On the one hand, the reactor 1 can be tilted at a certain angle to simulate the influence of downhole multiphase flow on the dielectric properties of the drilling fluid sample under test (such as the tendency of bubbles to rise); on the other hand, it facilitates sample removal or refilling during experimental preparation and completion. Because pneumatic drive is used, the noise source of the motor is avoided, reducing electromagnetic interference coupling at the source.

[0153] Specific steps for measuring the dielectric parameters of drilling fluids:

[0154] 1. Sample preparation and working condition setting: The drilling fluid to be tested (which can be water-based mud, oil-based mud, or foam mud with added gas) is injected into reactor 1. The reactor 1 is pressurized to the target pressure (0-80MPa). The drilling fluid to be tested is heated to the set temperature and kept constant. At the same time, gas is injected into the drilling fluid to be tested as needed to achieve the predetermined gas content. During the entire preparation process, the drilling fluid to be tested is stirred or reactor 1 is inverted to ensure that the temperature and pressure of the drilling fluid to be tested are uniform and stable, and the gas-liquid distribution is uniform.

[0155] 2. System Calibration: Before the formal measurement, switch the module and control the wideband impedance measurement module 2 to the standard vessel 6 to perform a measurement, obtain the zero bias and phase offset data of each frequency point under the cavity reference, and store them as calibration values. Adjust the gain and phase of the wideband impedance measurement module 2 as needed to make the measurement device achieve the expected measurement accuracy under the reference conditions.

[0156] 3. Measurement: The switching module controls the switching of the wideband impedance measurement module 2 to the reactor 1 containing the drilling fluid to be tested. The wideband impedance measurement module 2 sequentially outputs multiple different sinusoidal AC excitation voltage signals according to the set frequency range, i.e., performing point frequency scanning within the range of 1Hz to 100kHz. For each frequency point, the lock-in amplifier detector collects the current and phase difference passing through the drilling fluid to be tested at each frequency point, and calculates the complex impedance. The amplitude and phase of the measured drilling fluid are then used to further calculate the complex permittivity. Actually, the department and the virtual part The dielectric loss angle is calculated from the known electrode constant by converting the amplitude and phase. After stabilizing and measuring several cycles at each frequency point, the average value is recorded, and the zero bias and phase error obtained from the previous calibration are automatically subtracted to obtain the corrected and accurate data.

[0157] 4. Data Processing and Spectrum Generation: The dielectric parameters of the drilling fluid under test obtained at different frequencies are associated and stored with the corresponding environmental parameters (temperature, pressure, gas content). The measurement results are plotted into dielectric spectrum mapping curves through the plotting unit. For example, with frequency as the abscissa and dielectric constant or loss factor as the ordinate, the curve of the dielectric spectrum of the drilling fluid under test changing with frequency is obtained; or the change of dielectric constant with frequency under a certain temperature and pressure condition is represented by color or contour lines on a three-dimensional graph.

[0158] By comparing spectra under different temperatures, pressures, or gas-bearing conditions, the influence of environmental factors on the dielectric behavior of the drilling fluid under test can be analyzed intuitively. For example, the complex permittivity of the drilling fluid under test at low gas content can be determined. real part The complex permittivity of the drilling fluid changes gradually with frequency, but increases with increasing gas content. real part The overall decrease, with a more pronounced decrease at high frequencies, indicates that the addition of gas reduces dielectric polarization and introduces relaxation behavior. The dielectric spectrum obtained through this method can be used not only for detecting the composition of the drilling fluid but also for establishing a model relating the electrical properties of drilling mud to downhole operating conditions.

[0159] This invention can obtain the complex dielectric constant and loss angle data of the drilling fluid under test over a wide frequency range, and output a complete dielectric spectrum by combining information such as temperature, pressure, and gas content. The experimental results can accurately reflect the electrical characteristics of different types of drilling fluid samples in a simulated downhole environment, providing support for optimizing mud formulation and improving monitoring while drilling technology.

[0160] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for measuring the dielectric parameters of drilling fluids, characterized in that, The steps include the following: The drilling fluid to be tested is added into the reactor, and the reactor is set to the operating conditions. By setting a frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to the drilling fluid under test, and the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions are obtained. By converting the complex impedance at different frequency points, the complex permittivity of the drilling fluid under the corresponding AC electric field condition is obtained, and the corresponding dielectric loss tangent is calculated to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and the virtual part Dielectric loss tangent ; The operating parameters are correlated with the dielectric parameters at each different frequency point to generate a dielectric spectrum of dielectric parameters as the operating parameters change, where the operating parameters include temperature, pressure, and gas content. Before setting the frequency range and applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test, calibration is performed, including: Add the standard medium into a standard vessel identical to the reaction vessel; Within a set frequency range, sinusoidal AC excitation voltage signals at different frequency points are applied to a standard medium to obtain the amplitude and phase of the response signal of the standard medium under the corresponding AC electric field conditions. The baseline zero, gain, and phase data are obtained by averaging the amplitude and phase of multiple response signals. Based on the baseline zero, gain, and phase data, the compensation parameters are calculated, including zero offset, gain error, and phase error. By setting a frequency range and applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test, the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions are obtained, including: A 1Hz-100kHz sinusoidal AC excitation voltage signal is output through a wideband signal source; A sinusoidal AC excitation voltage signal of 1Hz-100kHz is applied to the drilling fluid under test by the guard electrode assembly; The voltage and current signals corresponding to each frequency point of the drilling fluid under test are collected, and the amplitude and phase of the complex impedance are calculated. The amplitude and phase of the complex impedance of the drilling fluid under test are corrected based on the compensation parameters under the corresponding AC electric field conditions.

2. The method of measuring the dielectric properties of a drilling fluid of claim 1, wherein, It also includes the identification of abnormal data, setting a data fluctuation threshold, comparing the dielectric parameters obtained by measuring the drilling fluid under different operating conditions multiple times with the set data fluctuation threshold, and marking the corresponding operating parameters when the dielectric parameters change abnormally.

3. A measuring device for measuring the method of measuring the dielectric parameter of a drilling fluid according to any one of claims 1 to 2, characterized in that, include: The reactor is used to add the drilling fluid to be tested and to set the operating conditions of the reactor. The measurement and control unit includes a wideband impedance measurement module, a data processing module, and a guard electrode assembly located on the inner right side of the reactor and capable of applying sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid to be measured. The wideband impedance measurement module sets the frequency range and applies sinusoidal AC excitation voltage signals at different frequency points to the drilling fluid under test through the guard electrode assembly to obtain the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions. The data processing module, combining the geometric parameters of the guard electrode assembly and the electrode equivalent model, converts all complex impedances to obtain the complex permittivity of the drilling fluid under the corresponding AC electric field conditions, and calculates the corresponding dielectric loss tangent to form the dielectric parameters at different frequency points. The complex permittivity includes the real part. and the virtual part Dielectric loss tangent ; The plotting unit correlates the operating parameters with the dielectric parameters at each different frequency point to generate a dielectric spectrum showing the change of dielectric parameters with the operating parameters, including frequency, temperature, pressure, and gas content.

4. The measuring device for the dielectric parameters of drilling fluid according to claim 3, characterized in that, The wideband impedance measurement module includes an adjustable frequency signal source and a lock-in amplifier detector; The adjustable frequency signal source outputs sinusoidal AC excitation voltage signals at different frequency points within a set frequency range; The lock-in amplifier detector collects the current and phase difference of the drilling fluid under test at each frequency point, and obtains the amplitude and phase of the complex impedance of the drilling fluid under test at each frequency point.

5. The apparatus of claim 4, wherein, It also includes a switching module, a baseline error analysis module, a correction error analysis module, and a standard vessel with the same structure as the reaction vessel that stores standard media. The switching module controls the switching of the wideband impedance measurement module to either a standard vessel or a reaction vessel. The reference error analysis module obtains baseline zero, gain, and phase data based on the average amplitude and phase of multiple response signals. Based on the baseline zero, gain, and phase data, it calculates compensation parameters, including zero offset, gain error, and phase error. The error correction analysis module corrects the amplitude and phase of the complex impedance of the drilling fluid under test under the corresponding AC electric field conditions based on the compensation parameters.

6. The apparatus of claim 5, wherein, Both the lower right side of the reactor and the lower right side of the standard reactor have a first mounting hole that connects internally and externally. A guard electrode assembly is installed in each of the first mounting holes. Both the lower left end of the reactor and the lower left end of the standard reactor have a second mounting hole that connects vertically. A filter through-chamber connector is installed in each of the second mounting holes. A three-coaxial guard measurement cable is installed in the filter through-chamber connector. An adjustable frequency signal source is connected to a switching module. The switching module is connected to the guard electrode assembly on the inner right side of the reactor and the guard electrode assembly on the inner right side of the standard reactor, respectively. The guard electrode assembly on the inner right side of the reactor is connected to the three-coaxial guard measurement cable on the inner left side of the reactor. The guard electrode assembly on the inner right side of the standard reactor is connected to the three-coaxial guard measurement cable on the inner left side of the standard reactor. Both the three-coaxial guard measurement cable on the inner left side of the reactor and the three-coaxial guard measurement cable on the inner left side of the standard reactor are connected to a lock-in amplifier detector.

7. The apparatus of claim 6, wherein, The reactor also includes a pressure pump, a constant temperature heating mechanism, a stirring shaft, stirring blades, a first pneumatic drive mechanism, and a working condition control module. A pressure port is located on the inner side of the upper part of the reactor. A gas injection pipeline is fixedly connected between the pressure port and the outlet of the pressure pump. A control valve is installed on the gas injection pipeline. A heating shell is located on the outer side of the reactor. A closed heating chamber is formed between the inner side of the heating shell and the outer side of the reactor. An inlet and outlet, which are connected internally and externally, are spaced apart on the outer side of the heating shell. The inlet and outlet of the heating shell are fixedly connected to the inlet and outlet of the constant temperature heating mechanism, respectively. A stirring shaft is located on the inner side of the lower part of the reactor. Several stirring blades are evenly distributed around the circumference on the outer side of the upper part of the stirring shaft. The lower end of the stirring shaft passes through the lower side of the reactor in a sealed manner. A first pneumatic drive mechanism is installed at the lower end of the reactor. The upper end of the output shaft of the first pneumatic drive mechanism is connected to the lower end of the stirring shaft. The working condition control module is connected to the pressure pump, the constant temperature heating mechanism, and the first pneumatic drive mechanism, respectively.

8. The apparatus of claim 7, wherein, It also includes a fixed frame and a second pneumatic drive mechanism. A tilting shaft is rotatably mounted on the upper part of the fixed frame. The outer side of the middle part of the tilting shaft is fixedly mounted to the lower end of the reactor. The second pneumatic drive mechanism is mounted on the side of the fixed frame. The output shaft of the second pneumatic drive mechanism is connected to the end of the tilting shaft. The second pneumatic drive mechanism is connected to the working condition control module.

Images