A core dielectric characteristic detection probe, detection method and detection device

Abstract

This application provides a core dielectric characteristic detection probe, detection method, and detection device, belonging to the field of core electrical testing and dielectric spectrum measurement technology. The core dielectric characteristic detection probe includes a probe structure. When performing a displacement experiment on the core, the working end face of the probe structure is adapted to clamp the core and continuously emit electromagnetic waves toward the core and receive the reflection coefficient to obtain the real-time electromagnetic parameters of the core. In the displacement experiment, the liquid can be discharged through the drainage groove on the working end face, enabling the probe structure to complete the clamping action of the core in the displacement experiment. It can also simultaneously perform dielectric spectrum acquisition in the displacement experiment, thereby realizing real-time and continuous dielectric spectrum acquisition in the displacement experiment through the probe structure.

Description

Technical Field

[0001] This application relates to the field of core electrical testing and dielectric spectrum measurement technology, and in particular to a core dielectric characteristic detection probe, detection method and detection device. Background Technology

[0002] In the field of core electrical property research, dielectric logging, as a type of electromagnetic logging method that is highly sensitive to fluid type, pore structure and saturation state, requires the establishment of a quantitative relationship between dielectric logging response and factors such as rock pore structure, oil-water distribution state and saturation. This necessitates conducting simulated displacement experiments in the laboratory. By controlling variables such as core saturation, pore pressure and displacement fluid type, the dynamic changes in the complex dielectric constant throughout the displacement process can be obtained, thus forming a rock-fluid coupled dielectric spectrum database.

[0003] Currently, widely used dielectric measurement methods (such as the resonant perturbation method and the parallel plate capacitance method) are used as measurement means.

[0004] However, the current dielectric measurement method using the resonant cavity method relies on removing the sample from the displacement experimental system and placing it into the resonant cavity to complete the measurement; the dielectric measurement method using the parallel plate method requires repeated loading and unloading of the core with a clamp. Neither method can meet the requirement of real-time continuous acquisition of dielectric spectra of the core during the displacement process. Summary of the Invention

[0005] This application provides a core dielectric characteristic detection probe, detection method, and detection device to solve the problem of not being able to meet the requirement of real-time continuous acquisition of dielectric spectra of cores during displacement.

[0006] In a first aspect, this application provides a core dielectric characteristic detection probe, comprising:

[0007] The probe structure is adapted to be placed on one side of the rock core; the end of the probe structure near the rock core is a working end face; the working end face is adapted to clamp the rock core; a drainage groove is provided on the working end face; the probe structure continuously emits electromagnetic waves toward the rock core through the working end face and receives the reflection coefficient to obtain the real-time complex dielectric constant of the rock core.

[0008] In one possible implementation, the drainage channel includes:

[0009] Several first slots;

[0010] Several second slots, each of which is connected to two adjacent first slots.

[0011] In one possible implementation, the frequency range of the complex permittivity is 10MHz-3GHz.

[0012] In one possible implementation, the probe structure includes:

[0013] A sealing part, the sealing part being adapted to be disposed at the second end of the rock core, and an installation hole being provided at the axial center of the sealing part;

[0014] The detection unit is disposed within the mounting hole; the end face of the detection unit near the core is the working end face; the detection unit is adapted to emit electromagnetic waves and receive reflected electromagnetic waves.

[0015] A spacer is disposed between the sealing part and the detection part; the spacer is made of insulating material.

[0016] In one possible implementation, the probe structure further includes:

[0017] An interface component is disposed on the side of the detection unit away from the core sample, and the interface component is electrically connected to the sealing unit;

[0018] An impedance analyzer is connected to the interface component, and the impedance analyzer calculates the electromagnetic parameters of the core by receiving the reflection coefficient through the sealing part.

[0019] A drainage hole penetrates the probe structure; one end of the drainage hole is connected to the drainage channel.

[0020] A drain pipe, the drain pipe being adapted to communicate with the drain hole.

[0021] Secondly, this application provides a detection method, comprising: during a core displacement experiment, placing the core dielectric characteristic detection probe described in any of the first aspects on one side of the core, with the working end face of the probe structure in close contact with the core, the probe structure emitting electromagnetic waves toward the core, and receiving the reflection coefficient as an electromagnetic parameter for inverting the complex dielectric constant of the rock; compensating the reflection coefficient using a three-load de-embedding technique to eliminate the phase shift and amplitude attenuation introduced by the transmission line, thereby extracting the equivalent reflection coefficient of the working end face of the probe structure;

[0022] After obtaining the accurate reflection coefficient through de-embedding technology, in order to obtain the complex permittivity using the reflection coefficient, an electromagnetic model of the coaxial probe can be established based on quasi-static theory, thereby obtaining the complex permittivity using the reflection coefficient.

[0023] Simulation results show that the probe structure can utilize the reflection coefficient to obtain the complex permittivity.

[0024] Thirdly, this application provides a detection device, comprising:

[0025] The main structure includes a receiving cavity; the receiving cavity is suitable for accommodating the rock core.

[0026] A displacement structure, the displacement structure being adapted to be disposed at a first end of the core; the displacement structure being adapted to displace the core using fluid;

[0027] A probe structure as described in any one of the first aspects is provided at the second end of the core; the probe structure continuously emits electromagnetic waves toward the core through the working end face and receives the reflection coefficient to obtain the real-time electromagnetic parameters of the core.

[0028] In one possible implementation, the cross-sectional shape of the probe structure in the direction of the working end face is the same as the cross-sectional shape of the receiving cavity in the direction of the working end face;

[0029] Also includes:

[0030] A sealing plug is disposed at the first end of the core within the receiving cavity;

[0031] The main structure includes:

[0032] The outer casing has an internal cavity for receiving the contents.

[0033] A rubber sleeve is disposed between the outer shell and the core.

[0034] In one possible implementation, the displacement structure includes:

[0035] Displacement pipeline, wherein the displacement pipeline passes through the sealing plug and is connected to the second end of the core;

[0036] A displacement pump, the displacement pump being adapted to be in communication with the displacement line, the displacement pump being adapted to provide driving force to the fluid.

[0037] In one possible implementation, it also includes:

[0038] A pressurization line, wherein the pressurization line is connected to the receiving cavity;

[0039] A pressure relief pipeline, which is connected to the pressurization pipeline;

[0040] A pressure pump, connected to a pressure pipeline, is provided in this application to increase the pressure within the containment cavity. The pressure pump is adapted to increase the pressure within the containment cavity. This application provides a core dielectric characteristic detection probe, detection method, and detection device. The core dielectric characteristic detection probe includes a probe structure. During a displacement experiment on the core, the working end face of the probe structure is adapted to clamp the core and continuously emit electromagnetic waves towards it, receiving the reflection coefficient to obtain the real-time electromagnetic parameters of the core. In the displacement experiment, liquid can be discharged through a drainage groove on the working end face, enabling the probe structure to clamp the core during the displacement experiment and simultaneously acquire dielectric spectrum data. Thus, the probe structure enables real-time and continuous dielectric spectrum acquisition during the displacement experiment. Attached Figure Description

[0041] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0042] Figure 1 This application provides a schematic diagram of the structure of a core dielectric characteristic detection probe.

[0043] Figure 2 This is a schematic diagram of the overall structure of a detection device provided in this application.

[0044] Figure Labels

[0045] 100. Main structure; 110. Outer shell; 120. Rubber sleeve; 130. Sealing plug;

[0046] 200. Displacement structure; 210. Displacement pipeline; 220. Displacement pump;

[0047] 300. Probe structure; 301. Working end face; 302. Drainage groove; 3021. First groove; 3022. Second groove; 303. Drainage hole; 304. Drainage pipe; 310. Sealing part; 320. Detection part; 330. Spacer; 340. Interface part; 350. Impedance analyzer;

[0048] 400, pressurization pump; 410, pressurization pipeline; 420, pressure relief pipeline.

[0049] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0050] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0051] First, let me explain the terms used in this application:

[0052] Simulated displacement experiments: Simulated displacement experiments are commonly used experimental methods in petroleum engineering, geological science, and environmental engineering. They are mainly used to study the flow patterns, displacement efficiency, and residual fluid distribution of fluids in porous media (such as rocks and soils). This experiment evaluates the impact of different displacement methods (such as water drive, gas drive, and chemical drive) on oil recovery by simulating fluid flow under reservoir conditions.

[0053] Resonance perturbation method: The resonance perturbation method is a perturbation analysis technique based on the resonance principle. It is mainly used to measure the electromagnetic parameters of materials (such as dielectric constant and magnetic permeability), study the field distribution in resonant cavities or waveguides, and analyze the influence of small physical changes on resonant systems.

[0054] In the existing technology, the dielectric measurement method relies on removing the sample from the displacement experimental system and placing it into the resonant cavity to complete the measurement; the dielectric measurement method using the parallel plate method requires repeated loading and unloading of the core with a holder. Neither method can meet the requirement of real-time continuous acquisition of dielectric spectra of the core during the displacement process.

[0055] To address the aforementioned problems, this application provides a core dielectric characteristic detection probe, detection method, and detection device. The core dielectric characteristic detection probe includes a probe structure. During a core displacement experiment, the working end face of the probe structure is adapted to clamp the core and continuously emit electromagnetic waves toward the core while receiving the reflection coefficient to obtain the real-time electromagnetic parameters of the core. During the displacement experiment, liquid can be discharged through a drainage groove on the working end face, enabling the probe structure to clamp the core during the displacement experiment and simultaneously acquire dielectric spectrum data. Thus, the probe structure achieves real-time and continuous dielectric spectrum acquisition during the displacement experiment.

[0056] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0057] Firstly, such as Figure 1As shown, this embodiment provides a core dielectric characteristic detection probe, including a probe structure 300, which is adapted to be placed on one side of the core; the end of the probe structure 300 near the core is a working end face 301; the working end face 301 is adapted to clamp the core; a drainage groove 302 is provided on the working end face 301; the probe structure 300 continuously emits electromagnetic waves toward the core through the working end face 301 and receives the reflection coefficient to obtain the real-time complex dielectric constant of the core.

[0058] It should be noted that the core is usually cylindrical, and the shape of the receiving cavity is the same as that of the core. In order to ensure the normal operation of the displacement experiment, the size of the working end face 301 of the probe structure 300 is the same as the size of the receiving cavity, so as to ensure that the receiving cavity is sealed during the displacement experiment. During the displacement experiment, the working end face 301 abuts against the core, thereby achieving the clamping effect on the core during the displacement experiment.

[0059] By setting a drainage channel 302 on the working end face 301, the liquid generated during the core displacement experiment can flow out along the drainage channel 302, ensuring the normal progress of the displacement experiment.

[0060] In this embodiment, by controlling the probe structure 300 to emit electromagnetic waves and receiving the reflection coefficient as an electromagnetic parameter for inverting the complex dielectric constant of the rock, continuous and real-time monitoring of the entire core displacement experiment process is achieved. This allows for the capture and measurement of the complete complex dielectric constant spectrum of the core over a wide frequency range at any time, according to experimental requirements. This avoids repeated core disassembly and assembly and interruptions to the displacement experiment. While significantly improving measurement efficiency and data accuracy, it also greatly increases the density of the dielectric spectrum measurement dataset during the displacement process, providing high-resolution experimental data support for accurately revealing the dynamic evolution of the dielectric spectrum during displacement.

[0061] Furthermore, such as Figure 2 As shown, the drainage trough 302 includes a plurality of first troughs 3021 and a plurality of second troughs 3022; wherein the plurality of first troughs 3021 are arranged at intervals from each other; wherein each second trough 3022 is connected to a first trough 3021.

[0062] It should be noted that the drainage trough 302 is composed of several first troughs 3021 and several second troughs 3022, which can increase the contact area between the drainage trough 302 and the core, ensuring that no water accumulation occurs after the liquid is displaced during the displacement experiment, thus affecting the displacement experiment.

[0063] Specifically, several first slots 3021 are concentric circles with equal spacing.

[0064] In this embodiment, the first groove 3021 consists of three concentric circles with equal spacing; the second groove 3022 consists of four straight grooves that pass through and connect the first groove 3021.

[0065] It should be noted that the first groove 3021 is designed as concentric circles with equal spacing, which provides the best coverage and ensures that no water accumulation occurs after the liquid is displaced during the displacement experiment. The second groove 3022 allows multiple first grooves 3021 to be interconnected, thus ensuring that the liquid can move between the first grooves 3021.

[0066] As an alternative implementation, the shape of the first groove 3021 can also be a straight groove, and a square mesh structure is formed by the cooperation of the first groove 3021 and the second groove 3022.

[0067] In this embodiment, the probe structure 300 includes a blocking part 310, a detection part 320, and a spacer 330. The blocking part 310 is adapted to be disposed at the second end of the core sample, and the end face of the blocking part 310 near the core sample is the working end face 301. A mounting hole is provided at the axial center of the blocking part 310. The detection part 320 is disposed within the mounting hole and is adapted to emit electromagnetic waves and receive reflected electromagnetic waves. The spacer 330 is disposed between the blocking part 310 and the detection part 320, and the spacer 330 is made of insulating material. The blocking part 310 and the detection part 320 are coaxial probes; the spacer 330 is specifically a glass insulator.

[0068] It should be noted that the detection unit 320, as the excitation and signal channel, transmits high-frequency electromagnetic waves to the probe end face. The excitation electric field radiates outward from the detection unit 320 and generates an impedance change upon contact with the measured medium, receiving and transmitting the reflected signal. The blocking unit 310 defines the electric field distribution between the blocking unit 310 and the detection unit 320, preventing external electromagnetic interference from affecting the measurement and preventing internal signals from radiating outward, ensuring the stability and controllability of signal transmission. The blocking unit 310 can also serve as a return path. The spacer 330 mechanically supports the detection unit 320 and fills the space between the blocking unit 310 and the detection unit 320, ensuring that the blocking unit 310 and the detection unit 320 are concentric. Electrically, the spacer 330 acts as a dielectric filler, determining the effective capacitance and characteristic impedance between the inner and outer conductors.

[0069] This embodiment provides a core dielectric characteristic detection probe, wherein the probe structure 300 further includes an interface 340 and an impedance analyzer 350; wherein the interface 340 is disposed on the side of the detection unit 320 away from the core, and the interface 340 is electrically connected to the detection unit 320; wherein the impedance analyzer 350 is connected to the interface 340, and the impedance analyzer 350 receives the reflection coefficient through the sealing part 310 to calculate the electromagnetic parameters of the core.

[0070] It should be noted that the interface component 340 has an internal thread at the interface, and the interface component 340 is connected to the connection line of the impedance analyzer 350 through a threaded connection.

[0071] Among them, the Impedance Analyzer 350 is an electronic testing instrument that evaluates the performance of an object by measuring complex impedance parameters. It uses phase-sensitive detection technology to simultaneously measure voltage and current, calculates parameters such as resistance, capacitance, and inductance based on an equivalent circuit model, and supports frequency scanning and graphical result display.

[0072] Furthermore, the probe structure 300 also includes a drain hole 303 and a drain pipe 304; wherein the drain hole 303 penetrates the probe structure 300; one end of the drain hole 303 is connected to the drain groove 302; and the drain pipe 304 is adapted to be connected to the drain hole 303.

[0073] Specifically, during the displacement experiment, the liquid first flows into the drainage tank 302, and then is discharged through the drainage hole 303 and the drainage pipe 304. The degree of displacement is assessed by monitoring the volume of the discharged liquid.

[0074] Secondly, embodiments of this application provide a detection method, which includes, during a core displacement experiment, placing a core dielectric characteristic detection probe as described in any of the first aspects on one side of the core, with the working end face of the probe structure 300 in close contact with the core, the probe structure 300 emitting electromagnetic waves toward the core, and receiving the reflection coefficient as an electromagnetic parameter for inverting the complex dielectric constant of the rock; and compensating for the reflection coefficient using a three-load de-embedding technique to eliminate the phase shift and amplitude attenuation introduced by the transmission line, thereby extracting the equivalent reflection coefficient of the working end face 301 of the probe structure 300.

[0075] After obtaining the accurate reflection coefficient through de-embedding technology, in order to obtain the complex permittivity using the reflection coefficient, an electromagnetic model of the coaxial probe can be established based on quasi-static theory, thereby obtaining the complex permittivity using the reflection coefficient.

[0076] Simulation results show that probe structure 300 can obtain the complex permittivity using the reflection coefficient.

[0077] It should be noted that during dielectric measurement, the impedance analyzer 350 controls the probe structure 300 to emit electromagnetic waves and receives the reflection coefficient as an electromagnetic parameter for inverting the complex dielectric constant of the rock. The reflection coefficient obtained by the instrument corresponds to the value at the working end face 301 of the detection unit 320. However, the reflection coefficient actually required for inversion is located on the working end face 301 of the sealing unit 310. To achieve this goal, the reflection coefficient is first compensated using a three-load de-embedding technique to eliminate the phase shift and amplitude attenuation introduced by the transmission line, thereby accurately extracting the equivalent reflection coefficient at the probe end face. The specific implementation steps are as follows: three media with known reflection coefficients are selected as calibration materials, and the reflection coefficients of the three media are measured using the probe, and the results are substituted into the following formula: (1)

[0078] In the formula, represents the finite directional error. Indicates frequency tracking error. This represents the equivalent source mismatch error. The reflection coefficient obtained by the instrument is [value], and the compensated reflection coefficient is [value]. By solving the three unknown parameters in Equation 1 through three calibrations, the relationship between the equivalent reflection coefficient of the probe end face and the instrument-measured reflection coefficient is obtained, thus achieving de-embedding compensation.

[0079] After obtaining the accurate reflection coefficient through de-embedding technology, an electromagnetic model of the coaxial probe can be established based on quasi-static theory to obtain the complex permittivity using the reflection coefficient. First, the radius of the detection part 320 in the probe structure 300 is defined as 'a', the radius of the sealing part 310 as 'b', and the complex permittivity of the spacer 330 as 'a'. The complex permittivity of the analyte is Assuming we only consider the single-mode propagation of the transverse electromagnetic wave (TEM) mode, then its composite electric field... Composite magnetic field It can be represented as:

[0080] (2)

[0081] (3)

[0082] In the formula:

[0083] (4)

[0084] (5)

[0085] in, Represents angular frequency and , The speed of light in a vacuum is represented by A, and the amplitude of the electric field of the positive wave at the end of the coaxial probe is represented by A. Represents the vacuum dielectric constant. Represents the permeability of free space. Indicates the permeability of the filling medium. Represents the reflection coefficient. The electric field applied to the sample. ,magnetic field It can be viewed as the integral superposition of all plane waves (including various higher-order modes of TE / TM) in the spectral domain, that is:

[0086] (6)

[0087] (7)

[0088] in, Represents the field amplitude in spectral domain form. This represents the magnetic permeability of the object being measured. This represents a first-order Bessel function of the first kind. It is derived from the following formula:

[0089] (8)

[0090] In the plane at z = 0, the transverse components of the electric and magnetic fields have continuous boundary conditions, from which we can deduce:

[0091] (9)

[0092] (10)

[0093] From the Fourier-Bessel integral formula, we know that:

[0094] (11)

[0095] in Let represent the nth-order Bessel function of the first kind. Multiply both sides of the above equation and then integrate, and then apply the orthogonality of the Bessel function and... The sieving property of the function yields:

[0096] (12)

[0097] Combining the above equation with the formula for the transverse component of the electric field (Equation 10), and assuming the transverse component of the electric field is 0, we can obtain:

[0098] (13)

[0099] By solving Equation 13, the complex permittivity of the rock can be obtained from the reflection coefficient φ. This equation is the relationship between the reflection coefficient and the permittivity of the analyte derived from the quasi-static model of the flat, holeless probe. Equation 13 contains the Bessel function with oscillatory characteristics. Since this equation does not have an analytical form, the Nelder-Mead simplex method is used for iterative inversion of the complex permittivity. The evaluation function defined for the inversion is:

[0100] (14)

[0101] in, This represents the true reflectance of the object being measured. This represents the reflection coefficient of the object under test, obtained through simulation and after de-embedding compensation. This represents the difference between the real parts of the two values. This represents the difference between the imaginary parts of the two. Then, the Nelder-Mead simplex method is used to search for the optimal complex permittivity that makes Equation 14 true, which is the complex permittivity of the core.

[0102] It should be noted that Equation 13 was derived based on the premise that the outer conductor surface of the probe is flat and free of pores. In this invention, to enable the probe structure 300 to meet the requirements of the displacement experiment, the probe structure 300 was modified by grooving and drilling to allow it to make good contact with the core and allow fluid to flow out. Simulation verification shows that the modified probe structure 300 can still use Equation 13 to invert the complex dielectric constant, and the modified probe structure 300 meets the sensitivity and accuracy requirements of dielectric spectrum measurement.

[0103] like Figure 2 As shown, in a third aspect, embodiments of this application provide a detection device, including a main structure 100 and a displacement structure 200. The main structure 100 has a receiving cavity; the receiving cavity is suitable for receiving a rock core; the displacement structure 200 is suitable for being disposed at the first end of the rock core; the displacement structure 200 is suitable for displacing the rock core using fluid.

[0104] A probe structure 300 of any one of the first aspects is provided at the second end of the core; the probe structure 300 continuously emits electromagnetic waves toward the core through the working end face 301 and receives the reflection coefficient to obtain the real-time electromagnetic parameters of the core.

[0105] Furthermore, the cross-sectional shape of the probe structure 300 in the direction of the working end face 301 is the same as the cross-sectional shape of the receiving cavity in the direction of the working end face 301; it also includes a sealing plug 130, which is disposed at the first end of the core inside the receiving cavity.

[0106] It should be noted that the probe structure 300 and the sealing plug 130 together constitute the sealed environment of the internal cavity.

[0107] Furthermore, the main structure 100 includes an outer shell 110 and a rubber sleeve 120. The outer shell 110 has an internal cavity, and the rubber sleeve 120 is disposed between the outer shell 110 and the core. By setting the rubber sleeve 120, it can be ensured that the core will not be displaced within the cavity.

[0108] Specifically, the displacement structure 200 includes a displacement pipe 210 and a displacement pump 220, wherein the displacement pipe 210 passes through the sealing plug 130 and is connected to the second end of the core, and the displacement pump 220 is connected to the displacement pipe 210 and provides driving force to the fluid.

[0109] The core displacement detection device provided in this embodiment also includes a pressurization pipeline 410, a pressure relief pipeline 420, and a pressurization pump 400. The pressurization pipeline 410 is connected to the receiving cavity; the pressure relief pipeline 420 is connected to the pressurization pipeline 410; the pressurization pump 400 is connected to the pressurization pipeline 410; and the pressurization pump 400 is adapted to increase the pressure in the receiving cavity.

[0110] It should be noted that a pressure relief valve is also installed on the pressure relief pipeline 420. After ensuring a tight seal, the pressure relief valve is closed, and the set confining pressure is applied via the pressurization pump 400. Then, the displacement pump 220 is started to displace the core sample using the required fluid. After the displacement experiment is completed, the displacement pump 220 is turned off, and the pressure relief valve is opened to release the pressure.

[0111] Specifically, the detection part 320 of the probe structure 300 has a stainless steel metal core, glass as the insulating material, and the outermost sealing part 310 is a chromium-nickel-iron alloy flange. However, any material that meets similar electrical characteristics (conductivity) can be used as a substitute. The parameters of the probe structure 300 in the embodiment are as follows:

[0112] Simulations were performed on the probe of the aforementioned dimensions, and the reflection coefficient of the PTFE calibration material obtained from the probe simulation was compared with the theoretical value to confirm that the dielectric constant calculation could still be performed using the smooth, holeless probe quasi-static model after the probe was modified. As shown in the figure below, the reflection coefficient calculated by forward modeling from the quasi-static model is consistent with the reflection coefficient of the modified coaxial probe after de-embedding compensation, with an average real part RE value of approximately 1.0% and an average RE value of approximately 0.2%. Both of the above error evaluation indicators are within a reasonable range, indicating that the detection accuracy and performance of the modified coaxial probe are in good agreement with the smooth, holeless probe quasi-static model, and the complex dielectric constant can be inverted using Equation 13.

[0113] After verifying the performance of the probe structure 300 through simulation, the measurement process in the implementation case is as follows:

[0114] Step 1: The core is processed into a cylinder with a diameter of 25.4 mm (1 in) and a length of 50 mm to fit the dimensions of the internal cavity of the outer shell 110, and is first pressurized and saturated with deionized water.

[0115] Step 2: Connect probe structure 300 to E4991B impedance analyzer 350, and use air, water and brass as calibration materials to perform de-embedding compensation.

[0116] Step 3: Connect the 2PB-00C horizontal flow pump to the inlet of the displacement pipeline 210. The horizontal flow pump is connected to the storage bottle, which contains displacement oil.

[0117] Step four: Place the core into the receiving cavity and assemble the sealing plug 130 and probe structure 300 into the receiving cavity.

[0118] Step 5: Connect pressurization line 410 to pressurization pump 400, close the pressure relief valve, and apply a confining pressure of 10MPa.

[0119] Step 6: Start the advection pump to begin displacement, and simultaneously manipulate the impedance analyzer 350 to obtain the reflection coefficient of the probe structure 300.

[0120] Step 7: Based on the measured reflection coefficient after de-embedding compensation, calculate the complex permittivity of the sample using the Nelder-Mead simplex method.

[0121] During the displacement process, steps six and seven are repeated multiple times to achieve online measurement of the dielectric spectrum during the displacement process.

[0122] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0123] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A core dielectric characteristic detection probe, characterized in that, include: The probe structure (300) is adapted to be placed on one side of the core; the end of the probe structure (300) near the core is a working end face (301); the working end face (301) is adapted to clamp the core; a drainage groove (302) is provided on the working end face (301); the probe structure (300) continuously emits electromagnetic waves toward the core through the working end face (301) and receives the reflection coefficient to obtain the real-time complex dielectric constant of the core; The probe structure (300) includes: A sealing part (310) is adapted to be disposed at the second end of the core, and an installation hole is provided at the axial center of the sealing part (310); The detection unit (320) is disposed in the mounting hole; the end face of the detection unit (320) near the core is the working end face (301); the detection unit (320) is adapted to emit electromagnetic waves and receive reflected electromagnetic waves. Spacer (330) is disposed between the sealing part (310) and the detection part (320); the spacer (330) is made of insulating material.

2. The core dielectric characteristic detection probe according to claim 1, characterized in that, The drainage channel (302) includes: Several first slots (3021); A plurality of second slots (3022), each second slot (3022) being connected to two adjacent first slots (3021).

3. The core dielectric characteristic detection probe according to claim 1, characterized in that, The frequency range of the complex permittivity is 10MHz-3GHz.

4. The core dielectric characteristic detection probe according to any one of claims 1-3, characterized in that, The probe structure (300) also includes: An interface component (340) is disposed on the side away from the core from the detection unit (320), and the interface component (340) is electrically connected to the sealing unit (310); Impedance analyzer (350), the impedance analyzer (350) is connected to the interface (340), the impedance analyzer (350) receives the reflection coefficient through the sealing part (310) to calculate the electromagnetic parameters of the core; A drain hole (303) is provided, which penetrates the probe structure (300); one end of the drain hole (303) is connected to the drain groove (302); A drain pipe (304) is adapted to communicate with the drain hole (303).

5. A detection method, characterized in that, include: During the core displacement experiment, the core dielectric characteristic detection probe according to any one of claims 1-4 is placed on one side of the core, and the working end face of the probe structure (300) is close to the core. The probe structure (300) emits electromagnetic waves toward the core and receives the reflection coefficient as an electromagnetic parameter for inverting the complex dielectric constant of the rock. The reflection coefficient is compensated by the three-load de-embedding technique to eliminate the phase shift and amplitude attenuation introduced by the transmission line, thereby extracting the equivalent reflection coefficient of the working end face (301) of the probe structure (300). After obtaining the accurate reflection coefficient through de-embedding technology, in order to obtain the complex permittivity using the reflection coefficient, an electromagnetic model of the coaxial probe can be established based on quasi-static theory, thereby obtaining the complex permittivity using the reflection coefficient. Simulation results show that the probe structure (300) can obtain the complex permittivity using the reflection coefficient.

6. A detection device, characterized in that, include: The main structure (100) has a receiving cavity inside; the receiving cavity is suitable for receiving rock cores. Displacement structure (200), the displacement structure (200) is adapted to be disposed at the first end of the core; the displacement structure (200) is adapted to displace the core using fluid; A core dielectric characteristic detection probe according to any one of claims 1-4 is provided at the second end of the core; the probe structure (300) continuously emits electromagnetic waves toward the core through the working end face (301) and receives the reflection coefficient to obtain the real-time electromagnetic parameters of the core.

7. The detection device according to claim 6, characterized in that, The cross-sectional shape of the probe structure (300) in the direction of the working end face (301) is the same as the cross-sectional shape of the receiving cavity in the direction of the working end face (301); Also includes: A sealing plug (130) is disposed at the first end of the core within the receiving cavity; The main structure (100) includes: The outer casing (110) has an internal cavity; A rubber sleeve (120) is disposed between the outer shell (110) and the core.

8. The detection device according to claim 7, characterized in that, The displacement structure (200) includes: Displacement conduit (210), the displacement conduit (210) passing through the sealing plug (130) and communicating with the second end of the core; Displacement pump (220), the displacement pump (220) being adapted to be in communication with the displacement line (210), the displacement pump (220) being adapted to provide driving force to the fluid.

9. The detection device according to claim 6, characterized in that, Also includes: A pressurized pipeline (410) is connected to the receiving cavity; A pressure relief line (420) is connected to the pressurization line (410); A pressure pump (400) is connected to the pressure line (410); the pressure pump (400) is adapted to increase the pressure in the receiving cavity.

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