Method for predicting mechanical parameters of rock containing hydrate sediments based on broadband electrical parameters

Abstract

The invention discloses a hydrate-containing sediment rock mechanical parameter prediction method based on broadband electrical parameters, which comprises the following steps of: firstly, determining an electrical parameter measurement method and a mechanical test combined measurement method, and obtaining the impedance of a hydrate-containing porous medium by applying excitation signals with different frequencies to an electrode; corresponding complex resistivity is calculated according to the size and distance of the electrical sensor and the impedance of the hydrate-containing porous medium, and meanwhile, mechanical parameters of the hydrate-containing porous medium are measured through a mechanical test. According to complex resistivity and mechanical parameters obtained through experiments, a mechanical parameter prediction model is established through linear fitting, polynomial fitting, a neural network and other methods. According to the method, combined measurement is carried out through multiple electrical measurement methods and multiple mechanical tests, so that an accurate mechanical parameter prediction model is established, and the method can be widely applied to the technical field of data processing.

Description

Technical Field

[0001] The invention relates to the technical field of data processing, and in particular to a method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters. Background Art

[0002] Rock mechanical parameters are key data in geological exploration and engineering development, especially when it comes to hydrate-containing reservoirs, where mechanical parameters directly affect reservoir stability and mining safety. Natural gas hydrates, as an unconventional energy source with huge resource potential, are mainly found in high-pressure, low-temperature marine continental margins and permafrost areas. Since hydrates decompose during the mining process, resulting in unstable formations and increased mining risks, accurate prediction of rock mechanical parameters is crucial to the development of hydrate resources.

[0003] In traditional rock mechanics research, in-situ measurement of rock mechanics parameters is difficult, and they are often measured using laboratory mechanical experiments, such as triaxial tests, unconfined compression tests, etc. Although these methods are accurate, they are usually time-consuming and costly, especially in large-scale geological exploration or deep underground engineering, where the testing difficulty and cost are more significant. Summary of the invention

[0004] The present invention aims to solve the problem of related technical limitations at least to a certain extent. To this end, the present invention proposes a method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters, which can conveniently realize the prediction of rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters.

[0005] On the one hand, an embodiment of the present invention provides a method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters, comprising the following steps:

[0006] Acquire a sample set; the sample set includes samples of a plurality of hydrate-containing sediment rocks with different saturations;

[0007] Based on the first mechanical test, the shear strength of each sample in the sample set under different axial stresses is measured in sequence, and based on the first electrical measurement method, the impedance corresponding to each sample under different states is measured synchronously and jointly to obtain first correlation data of the impedance and shear strength of each sample;

[0008] The compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence based on the second mechanical test, and the impedance corresponding to each sample is measured synchronously and jointly based on the second electrical measurement method to obtain second correlation data of the impedance and the compressive strength of each sample; the compressive strength is determined based on the axial stress applied by the second mechanical test;

[0009] Based on the geometric parameters of the electrical sensor used in the electrical measurement method combined with the impedance, the resistivity corresponding to the sample in different states is obtained; the electrical measurement method includes a first electrical measurement method and a second electrical measurement method;

[0010] Based on the resistivity corresponding to the sample in different states, the first correlation data is converted into third correlation data of the resistivity and shear strength of the sample, and the second correlation data is converted into fourth correlation data of the resistivity and compressive strength;

[0011] Based on the test results of the first mechanical test, a first correlation curve of shear strength and axial stress is constructed, and then according to the Coulomb shear strength theory, the internal friction angle and cohesion corresponding to the shear strength of the sample under different axial stresses are obtained; and then according to the third correlation data, the fifth correlation data of the resistivity and internal friction angle of the sample and the sixth correlation data of the resistivity and cohesion are obtained;

[0012] Based on the test results of the second mechanical test, a second correlation curve of axial strain and axial stress is constructed, and the compression modulus corresponding to the axial strain of the sample under different axial stresses is obtained according to the slope of the second correlation curve; and then the seventh correlation data of the resistivity and compression modulus of the sample is obtained according to the fourth correlation data;

[0013] Performing data fitting on the third associated data, the fourth associated data, the fifth associated data, the sixth associated data and the seventh associated data to obtain a mechanical parameter prediction model; the mechanical parameter prediction model includes a shear strength prediction model, a compressive strength prediction model, an internal friction angle prediction model, a cohesion prediction model and a compression modulus prediction model;

[0014] Among them, the mechanical parameter prediction model is used to obtain the mechanical parameters of the rock to be predicted based on the resistivity of the rock to be predicted.

[0015] On the other hand, an embodiment of the present invention provides an electronic device, including: a processor and a memory; the memory is used to store programs; the processor executes the program to implement the above-mentioned method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters.

[0016] On the other hand, an embodiment of the present invention provides a computer storage medium, which stores a program executable by a processor. When the program executable by the processor is executed by the processor, it is used to implement the above-mentioned method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters.

[0017] The embodiment of the present invention obtains a sample set; the sample set includes samples of hydrate-containing sediment rocks with multiple different saturations; based on a first mechanical test, the shear strength of each sample in the sample set under different axial stresses is measured in sequence, and based on a first electrical measurement method, the impedance corresponding to each sample in different states is measured synchronously and jointly, and first correlation data of the impedance and shear strength of each sample is obtained; based on a second mechanical test, the compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence, and based on a second electrical measurement method, the impedance corresponding to each sample is measured synchronously and jointly, and second correlation data of the impedance and compressive strength of each sample is obtained; the compressive strength is determined based on the axial stress applied by the second mechanical test; based on the geometric parameters of the electrical sensor applied by the electrical measurement method combined with the impedance, the resistivity corresponding to the sample in different states is obtained; the electrical measurement method includes a first electrical measurement method and a second electrical measurement method; based on the resistivity corresponding to the sample in different states, the first correlation data is converted into third correlation data of the resistivity and shear strength of the sample, and the second correlation data is converted into third correlation data of the resistivity and compressive strength Four associated data; based on the test results of the first mechanical test, a first associated curve of shear strength and axial stress is constructed, and then according to the Coulomb shear strength theory, the internal friction angle and cohesion corresponding to the shear strength of the sample under different axial stresses are obtained; then according to the third associated data, the fifth associated data of the resistivity and internal friction angle of the sample and the sixth associated data of the resistivity and cohesion are obtained; based on the test results of the second mechanical test, a second associated curve of axial strain and axial stress is constructed, and according to the slope of the second associated curve, the compression modulus corresponding to the axial strain of the sample under different axial stresses is obtained; then according to the fourth associated data, the seventh associated data of the resistivity and compression modulus of the sample is obtained; the third associated data, the fourth associated data, the fifth associated data, the sixth associated data and the seventh associated data are fitted to obtain a mechanical parameter prediction model; the mechanical parameter prediction model includes a shear strength prediction model, a compressive strength prediction model, an internal friction angle prediction model, a cohesion prediction model and a compression modulus prediction model; wherein, the mechanical parameter prediction model is used to obtain the mechanical parameters of the rock to be predicted based on the resistivity prediction of the rock to be predicted. The present invention uses an electrical parameter measurement method and a mechanical test combined measurement method to measure various mechanical parameters of hydrate-containing porous media through mechanical tests, and simultaneously obtains the impedance of hydrate-containing porous media through electrical measurement methods, and then calculates the corresponding resistivity according to the size and distance of the electrical sensor and the impedance of the hydrate-containing porous media, and obtains the electrical and mechanical correlation data. Finally, based on the resistivity and mechanical parameters obtained in the experiment, a mechanical parameter prediction model is established by data fitting.The present invention constructs a prediction model by fitting the data association of electrical parameters and mechanical parameters, and then in the subsequent rock mechanical parameter prediction based on the mechanical parameter prediction model, it is possible to conveniently predict the mechanical parameters based on the wide-band electrical parameters of the rock and realize recycling, thus avoiding the tediousness of the traditional method of relying purely on mechanical measurements and having to re-perform mechanical tests every time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0019] Figure 1 A schematic flow chart of a method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a combined measurement of a contact-type two-electrode method and a direct shear test provided in an embodiment of the present invention;

[0021] Figure 3a A side view schematic diagram of a combined measurement of a contact-type two-electrode method and a ring shear test provided in an embodiment of the present invention;

[0022] Figure 3b A schematic top view of a combined measurement of a contact-type two-electrode method and a ring shear test provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a non-contact two-electrode method and a direct shear test combined measurement provided by an embodiment of the present invention;

[0024] Figure 5a A side view schematic diagram of a non-contact two-electrode method and a ring shear test combined measurement provided by an embodiment of the present invention;

[0025] Figure 5b A schematic top view of a non-contact two-electrode method and a ring shear test combined measurement provided by an embodiment of the present invention;

[0026] Figure 6a A side view schematic diagram of a non-contact Van der Pauw method and a ring shear test combined measurement provided by an embodiment of the present invention;

[0027] Figure 6b A schematic top view of a non-contact Van der Pauw method and a ring shear test combined measurement provided by an embodiment of the present invention;

[0028] Figure 7 A schematic diagram of a combined measurement of a contact-type two-electrode method and a triaxial test provided in an embodiment of the present invention;

[0029] Figure 8 A schematic diagram of a non-contact two-electrode method and a triaxial test combined measurement provided by an embodiment of the present invention;

[0030] Figure 9a A side view schematic diagram of a joint measurement of a contact-type three-electrode method and an unconfined compression test provided in an embodiment of the present invention;

[0031] Figure 9b A schematic top view of a combined measurement of a contact-type three-electrode method and an unconfined compression test provided in an embodiment of the present invention;

[0032] Fig.10a A side view schematic diagram of a combined measurement of the contact-type Van der Pauw method and the unconfined compression test provided by an embodiment of the present invention;

[0033] Fig.10b A schematic top view of a combined measurement of the contact-type Van der Pauw method and the unconfined compression test provided in an embodiment of the present invention;

[0034] Fig.11 A schematic diagram of a combined measurement of a contact-type four-probe method and a triaxial test provided in an embodiment of the present invention;

[0035] Fig.12 A schematic diagram of a process for establishing a mechanical parameter prediction model provided by an embodiment of the present invention;

[0036] Fig.13 A schematic diagram of the relationship between the real part of complex resistivity and shear strength under different axial pressures provided by an embodiment of the present invention;

[0037] Fig.14 A schematic diagram of the relationship between the imaginary part of complex resistivity and shear strength under different axial pressures provided by an embodiment of the present invention;

[0038] Fig.15 A schematic diagram of the relationship between the real part of complex resistivity and the internal friction angle provided in an embodiment of the present invention;

[0039] Fig.16 A schematic diagram of the relationship between the internal friction angle and the imaginary part of the complex resistivity provided by an embodiment of the present invention;

[0040] Fig.17 A schematic diagram of the relationship between the real part of complex resistivity and cohesion provided by an embodiment of the present invention;

[0041] Fig.18 A schematic diagram of the relationship between the imaginary part of complex resistivity and cohesion provided by an embodiment of the present invention;

[0042] Fig.19 A schematic diagram of the relationship between the real part of complex resistivity and compressive strength provided by an embodiment of the present invention;

[0043] Fig. 20 A schematic diagram of the relationship between the imaginary part of complex resistivity and compressive strength provided by an embodiment of the present invention;

[0044] Fig.21 A schematic diagram of the relationship between the real part of complex resistivity and the compression modulus provided by an embodiment of the present invention;

[0045] Fig. 22 A schematic diagram of the relationship between the imaginary part of complex resistivity and the compression modulus provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first / S100", "second / S200", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] To facilitate the understanding of the technical solution of the present invention, the meanings of the parameters that may be cited in the embodiments of the present invention and their technical principles are first explained:

[0050] Electrical parameter measurement method and mechanical test:

[0051] 1) Electrical measurement method:

[0052] As shown in Table 1, the electrical measurement methods involved in the present invention are divided into two categories: contact and non-contact. The contact electrical measurement methods include a two-electrode method, a three-electrode method, a Van der Pauw method and a four-probe method. The non-contact electrical measurement methods include a two-electrode method and a Van der Pauw method.

[0053] Table 1

[0054]

[0055] 2) Mechanical test:

[0056] As shown in Table 2, the mechanical tests involved in the present invention include direct shear test, ring shear test, triaxial test and unconfined compression test.

[0057] Table 2

[0058]

[0059] Reference Figure 1 , Figure 1 The flowchart of the method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters applied to a server provided in an embodiment of the present invention, the execution subject of the method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters can be any of the aforementioned computer devices (including servers or terminals). Figure 1 , the method comprises the following steps:

[0060] S100, obtaining a sample set; the sample set includes a plurality of samples of hydrate-containing sediment rocks with different saturations;

[0061] S200, based on the first mechanical test, sequentially measure the shear strength of each sample in the sample set under different axial stresses, and based on the first electrical measurement method, synchronously and jointly measure the impedance of each sample under different states, to obtain first correlation data of the impedance and shear strength of each sample;

[0062] It should be noted that, in some embodiments, step S200 may include the following steps: measuring the shear strength of each sample in the sample set under different axial stresses in turn through a direct shear test, and obtaining the impedance corresponding to each sample in different states through a synchronous joint measurement based on a contact two-electrode method through an impedance analyzer, so as to obtain the first correlation data of the impedance and shear strength of each sample; wherein, a single direct shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a first preset condition during the shear treatment, determines the shear strength according to the shear stress, and performs synchronous joint measurement based on the contact two-electrode method through an impedance analyzer.

[0063] For example, in some embodiments, the contacting two-electrode method is combined with the direct shear test to measure the resistivity of the sample in relation to the shear strength, cohesion and internal friction angle. Figure 2 As shown ( Figure 2 The corresponding meanings of the reference numerals are: 1—upper electrode plate; 2—insulating sleeve; 3—piston; 4—platform; 5—sample; 6—lower electrode plate). The application principle of the contact two-electrode method and the direct shear test combined measurement is as follows:

[0064] By applying current to the upper and lower electrode plates and measuring the voltage drop, the resistance R of the sample is measured according to Ohm's law:

[0065]

[0066] Where: U is the voltage and I is the current through the sample.

[0067] The resistivity of the sample can be calculated according to the following formula:

[0068]

[0069] Where: A 1 is the equivalent contact area of ​​the electrodes, and L is the distance between the electrodes (equivalent to the sample thickness).

[0070] At the same time, a vertical load is applied to the sample, and a lateral stress is applied to the upper part of the sample through the piston, while the platform fixes the lower part of the sample, forcing the sample to produce shear failure on a specific plane, thereby measuring the shear strength of the sample. According to Coulomb shear strength theory, the shear strength τ of the sample can be expressed as:

[0071]

[0072] Where: τ is the shear strength of the sample, c is the cohesion of the sample, and σ is the normal stress; is the internal friction angle of the sample, representing the effect of friction between soil particles.

[0073] The specific experimental steps can be implemented as follows:

[0074] ① The lower electrode plate, insulating sleeve and platform are integrated. The hydrate sediment is added to the insulating sleeve while being compacted. After the sample fills the insulating sleeve, the upper electrode plate is placed on the sample and pressed repeatedly to ensure full contact between the electrode and the sample.

[0075] ② Apply AC excitation signals of different frequencies to the two electrodes through the impedance analyzer, and measure the output signals of the two electrodes at the same time to obtain the sample impedance. Apply 50kPa axial stress to the sample and keep it constant, let the piston shear at a rate of 1mm / min. When the shear stress reading reaches stability or retreats significantly, it means that the sample has been sheared. It is advisable to shear until the shear deformation reaches 4mm. When the shear stress reading continues to increase, the shear deformation should reach 6mm. The shear stress at this time is the shear strength, and the sample impedance at this time is measured at the same time.

[0076] ③ Change the axial stress applied to the sample to 100 kPa, 150 kPa, and 200 kPa, repeat experimental steps ① and ② in sequence, and record the measured impedance and shear strength.

[0077] ④Change the saturation of the sample, repeat steps ①, ② and ③, and record the measured sample impedance and shear strength.

[0078] It should be noted that, in some embodiments, step S200 may also include the following steps: measuring the shear strength of each sample in the sample set under different axial stresses in turn through a ring shear test, and obtaining the impedance corresponding to each sample in different states through a synchronous joint measurement based on a contact two-electrode method through an impedance analyzer, so as to obtain the first correlation data of the impedance and shear strength of each sample; wherein, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a second preset condition during the shear treatment, determines the shear strength according to the shear stress, and performs synchronous joint measurement based on the contact two-electrode method through an impedance analyzer.

[0079] For example, in some embodiments, the contacting two-electrode method is combined with the ring shear test to measure the resistivity of the sample in relation to the shear strength, cohesion and internal friction angle. Figure 3a (side view) and Figure 3b (Top view) Figure 3a and Figure 3b The corresponding meanings of the reference numerals are: 1—upper electrode plate; 2—sample box; 3—sample; 4—lower electrode plate). The application principle of the contact two-electrode method and the ring shear test combined measurement is as follows:

[0080] The upper and lower sample boxes are fixed to the upper and lower electrodes respectively. By applying current to the upper and lower electrodes and measuring the voltage drop, the resistivity of the ring sample can be obtained according to equations (1) and (2).

[0081] A vertical load is applied to the sample, and the sample box is rotated to apply hoop stress to the sample, causing shear deformation of the sample, thereby measuring the shear strength of the sample. Similar to the direct shear test, the ring shear test results are explained by formula (3).

[0082] The specific experimental steps can be implemented as follows:

[0083] ① The upper and lower electrodes are integrated with the upper and lower sample boxes respectively. The sample is made into a ring-shaped sample according to the size of the sample box, placed in the lower sample box, and the upper sample box is covered. Press repeatedly to ensure that the electrode is in full contact with the sample.

[0084] ② Apply AC excitation signals of different frequencies to the two electrodes through the impedance analyzer, and measure the output signals of the two electrodes at the same time to obtain the impedance of the sample. Apply 50kPa axial stress to the sample and keep it constant, let the lower sample box shear at a rate of 1° / min. When the shear stress reading decreases, it means that the sample has been sheared. The shear stress at this time is the shear strength, and the sample impedance at this time is measured and calculated.

[0085] ③ Change the axial stress applied to the sample to 100 kPa, 150 kPa, and 200 kPa, repeat experimental steps ① and ② in sequence, and record the measured sample impedance and shear strength.

[0086] ④Change the saturation of the sample, repeat steps ①, ② and ③, and record the measured sample impedance and shear strength.

[0087] It should be noted that, in some embodiments, step S200 may also include the following steps: measuring the shear strength of each sample in the sample set under different axial stresses in turn through a direct shear test, and obtaining the impedance corresponding to each sample in different states through a synchronous joint measurement based on a non-contact two-electrode method through an impedance analyzer, so as to obtain the first correlation data of the impedance and shear strength of each sample; wherein, a single direct shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a third preset condition during the shear treatment, determines the shear strength according to the shear stress, and performs synchronous joint measurement based on the non-contact two-electrode method through an impedance analyzer.

[0088] For example, in some embodiments, the non-contact two-electrode method is combined with the direct shear test to measure the resistivity of the sample in relation to the shear strength, cohesion and internal friction angle. Figure 4 As shown ( Figure 4 The corresponding meanings of the reference numerals are: 1—insulating sleeve; 2—platform; 3—piston; 4—sample; 5—electrode). The application principle of the non-contact two-electrode method and the direct shear test combined measurement is as follows:

[0089] The two electrodes are the excitation electrode and the detection electrode. When the sensor is working, an AC excitation signal u is applied to the excitation electrode. i At this time, the excitation electrode, the sample container wall and the sample to be tested will form a coupling capacitor C 1 Similarly, the detection electrode, the sample container wall and the sample to be tested will form a coupling capacitor C 2 The two coupling capacitors C 1 and C 2 And the equivalent conductivity R of the sample to be tested x An AC measurement path will be formed, and the output current i O It can be expressed as:

[0090]

[0091] Where f is the AC excitation signal u i The excitation frequency is Figure 4As shown, connecting an inductor in series in the circuit can eliminate the influence of the coupling capacitor. The impedance of the sample can be obtained by an impedance analyzer, and then the resistivity of the sample can be calculated.

[0092] The transverse stress is applied to the sample by the piston. Similarly, the shear strength is measured when the sample is destroyed. The cohesion and internal friction angle of the sample are calculated according to formula (3).

[0093] The specific experimental steps can be implemented as follows:

[0094] ① Add the sample to the insulating sleeve and compact it while adding. The two electrodes are conductive silver paint, which is applied on the outside of the insulating sleeve, does not contact the sample and will change with the shape of the insulating sleeve.

[0095] ②Through impedance analysis, apply AC excitation signals of different frequencies to the upper electrode, and obtain the sample impedance by detecting the output signal of the lower electrode. Apply 50kPa axial stress to the sample and keep it constant, and let the piston shear at a rate of 1mm / min. When the shear stress reading reaches a stable state or retreats significantly, it means that the sample has been sheared. It is advisable to shear until the shear deformation reaches 4mm. When the shear stress reading continues to increase, the shear deformation should reach 6mm. The shear stress at this time is the shear strength, and the sample impedance at this time is measured at the same time.

[0096] ③ Change the axial stress applied to the sample to 100 kPa, 150 kPa, and 200 kPa, repeat experimental steps ① and ② in sequence, and record the measured sample impedance and shear strength.

[0097] ④Change the saturation of the sample, repeat steps ①, ② and ③, and record the measured sample impedance and shear strength.

[0098] It should be noted that, in some embodiments, step S200 may also include the following steps: measuring the shear strength of each sample in the sample set under different axial stresses in turn through a ring shear test, and obtaining the impedance corresponding to each sample in different states through a synchronous joint measurement based on a non-contact two-electrode method through an impedance analyzer, so as to obtain the first correlation data of the impedance and shear strength of each sample; wherein, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a fourth preset condition during the shear treatment, determines the shear strength according to the shear stress, and performs synchronous joint measurement based on the non-contact two-electrode method through an impedance analyzer.

[0099] For example, in some embodiments, the non-contact two-electrode method is combined with the ring shear test to measure the resistivity of the sample in conjunction with the shear strength, cohesion and internal friction angle. Figure 5a and Figure 5b As shown ( Figure 5a and Figure 5b The corresponding meanings of the reference numerals are: 1—load plate; 2—sample box; 3—electrode; 4—sample). The application principle of the non-contact two-electrode method combined with the ring shear test is as follows:

[0100] As 5a and Figure 5b As shown, the upper electrode is used as an excitation electrode to apply an excitation signal, the lower electrode is used as an output electrode, and the series inductor eliminates the influence of the coupling capacitor. Similarly, the impedance of the sample is finally obtained by the impedance analyzer, and then the resistivity of the sample is calculated.

[0101] The hoop stress is applied to the sample through the load plate. Similarly, the shear strength is measured when the sample is destroyed. The cohesion and internal friction angle of the sample are calculated according to formula (3).

[0102] The specific experimental steps can be implemented as follows:

[0103] ① Add the sample to the insulating sleeve and compact it while adding.

[0104] ② Apply AC excitation signals of different frequencies to the upper electrode through the impedance analyzer, measure the sample impedance by detecting the output signal of the lower electrode, and then calculate the sample impedance. Apply 50kPa axial stress to the sample and keep it constant, let the load plate shear at a rate of 1° / min. When the shear stress reading decreases, it means that the sample has been sheared. The shear stress at this time is the shear strength, and the sample impedance at this time is measured at the same time.

[0105] ③ Change the axial stress applied to the sample to 100 kPa, 150 kPa, and 200 kPa, repeat experimental steps ① and ② in sequence, and record the measured sample impedance and shear strength.

[0106] ④Change the saturation of the sample, repeat steps ①, ② and ③, and record the measured sample impedance and shear strength.

[0107] It should be noted that, in some embodiments, step S200 may also include the following steps: measuring the shear strength of each sample in the sample set under different axial stresses in turn through a ring shear test, and obtaining the impedance corresponding to each sample in different states through a synchronous joint measurement based on a non-contact Van der Pauw method through an impedance analyzer, so as to obtain the first correlation data of the impedance and shear strength of each sample; wherein, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a fifth preset condition during the shear treatment, determines the shear strength according to the shear stress, and performs synchronous joint measurement based on the non-contact Van der Pauw method through an impedance analyzer.

[0108] For example, in some embodiments, the non-contact Van der Pauw method is combined with the ring shear test to measure the resistivity of the sample in relation to the shear strength, cohesion and internal friction angle. Figure 6a and Figure 6b As shown ( Figure 6a and Figure 6b The corresponding meanings of the reference numerals are: 1—load plate; 2—sample; 3—sample box; 4—electrode sheet). The application principle of the non-contact two-electrode method combined with the ring shear test is as follows:

[0109] As 6a and Figure 6b As shown, four metal electrodes are placed outside the insulating sample box, named 1, 2, 3 and 4 respectively. The adjacent metal electrodes 1 and 2 are used as excitation electrodes and connected to the excitation source. The metal electrodes 3 and 4 are used as detection electrodes and connected to the signal processing and acquisition module. By applying AC voltage excitation to the two excitation electrodes, AC voltage output signals can be obtained on the two detection electrodes. The amplitude of the signal changes with the change of resistivity. Finally, the sample impedance is obtained by the impedance analyzer, and then the resistivity of the sample is calculated.

[0110] The hoop stress is applied to the sample through the loading plate. Similarly, the shear strength is measured when the sample is damaged. The cohesion and internal friction angle of the sample are calculated according to formula (3).

[0111] The specific experimental steps can be implemented as follows:

[0112] ① Add the sample into the sample box and compact it while adding.

[0113] ② Apply AC excitation signals of different frequencies to two adjacent electrodes through an impedance analyzer, measure the sample impedance by detecting the output signals of the other two electrodes, and then calculate the sample impedance. Apply 50kPa axial stress to the sample and keep it constant, let the load plate shear at a rate of 1° / min. When the shear stress reading decreases, it means that the sample has been sheared. The shear stress at this time is the shear strength, and the sample impedance at this time is measured at the same time.

[0114] ③ Change the axial stress applied to the sample to 100 kPa, 150 kPa, and 200 kPa, repeat experimental steps ① and ② in sequence, and record the measured sample impedance and shear strength.

[0115] ④Change the saturation of the sample, repeat steps ①, ② and ③, and record the measured sample impedance and shear strength.

[0116] S300, based on the second mechanical test, sequentially measure the compressive strength and the corresponding axial strain of each sample in the sample set, and based on the second electrical measurement method, synchronously and jointly measure the impedance corresponding to each sample to obtain second correlation data of the impedance and compressive strength of each sample;

[0117] Wherein, the compressive strength is determined based on the axial stress applied by the second mechanical test;

[0118] It should be noted that, in some embodiments, step S300 may include the following steps: measuring the compressive strength and the corresponding axial strain of each sample in the sample set in turn through a triaxial test, and obtaining the impedance corresponding to each sample through a two-electrode method through a synchronous joint measurement using an impedance analyzer, to obtain second related data of the impedance and compressive strength of each sample; wherein the triaxial test applies axial stress to the sample at a preset downward speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the two-electrode method, the impedance of the sample at the corresponding moment is synchronously and jointly measured through an impedance analyzer.

[0119] It should also be noted that the two-electrode method includes a contact two-electrode method and a non-contact two-electrode method.

[0120] For example, in some embodiments, the contact two-electrode method is combined with the triaxial test to measure the resistivity of the sample in relation to the compressive strength and the compression modulus. Figure 7 As shown, ( Figure 7 The corresponding meanings of the reference numerals are: 1-piston; 2-exhaust hole; 3-electrode plate; 4-pressure chamber; 5-sample; 6-insulating sleeve; 7-inlet hole). The application principle of the contact two-electrode method and the triaxial test combined measurement is as follows:

[0121] like Figure 7 As shown, current is applied to the upper and lower electrodes and the voltage drop is measured. Similarly, the resistivity of the ring sample can be obtained according to equations (1) and (2).

[0122] The axial stress applied to the sample can be adjusted by controlling the piston, and the confining pressure applied to the sample can be adjusted by controlling the exhaust and air inlet holes of the pressure chamber. The compressive strength refers to the maximum stress that the sample can withstand before failure. This parameter can be obtained by a dynamometer. The compression modulus is the elastic modulus of the material, which represents the ratio of the stress to the strain of the material. The compression modulus E is calculated by the linear part of the axial stress and axial strain in the triaxial test:

[0123]

[0124] Where: Δσ is the change in axial stress, and Δε is the change in axial strain.

[0125] The specific experimental steps can be implemented as follows:

[0126] ① The electrode plate and the insulating sleeve form a sample box. Add the sample to the sample box and compact it while adding. After the sample fills the insulating sleeve, place the upper electrode plate on the sample and press repeatedly to ensure that the electrode is in full contact with the sample.

[0127] ② Apply AC excitation signals of different frequencies to the two electrodes through an impedance analyzer, and measure the output signals of the two electrodes at the same time to obtain the impedance of the sample. The piston applies axial stress to the sample at a downward pressure speed of 1mm / min, adjusts the air inlet and outlet to ensure constant confining pressure, and monitors the axial strain, confining pressure and applied axial stress of the sample in real time until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance at this time is measured and calculated.

[0128] ③ Change the saturation of the sample, repeat the above steps, and record the measured sample impedance, compressive strength, axial stress and axial strain.

[0129] For example, in some embodiments, the non-contact two-electrode method is combined with the triaxial test to measure the resistivity of the sample in relation to the compressive strength and compression modulus. Figure 8 As shown, ( Figure 8 The corresponding meanings of the reference numerals are: 1-piston; 2-exhaust hole; 3-pressure chamber; 4-electrode; 5-sample; 6-insulating sleeve; 7-inlet hole). The application principle of the non-contact two-electrode method and the triaxial test combined measurement is as follows:

[0130] The upper electrode is used as an excitation electrode to apply an excitation signal to it, and the lower electrode is used as an output electrode. The series inductor eliminates the influence of the coupling capacitor. Similarly, the sample impedance is finally obtained by the impedance analyzer, and then the sample impedance is calculated.

[0131] Axial pressure is applied to the sample through the piston, and confining pressure is applied to the sample through the pressure chamber. Similarly, the compressive strength of the sample is obtained according to the dynamometer, and the compression modulus of the sample is obtained according to formula (5).

[0132] The specific experimental steps can be implemented as follows:

[0133] ① Add the sample to the insulating sleeve and compact it while adding.

[0134] ② Apply AC excitation signals of different frequencies to the upper electrode through an impedance analyzer, measure the sample impedance by detecting the output signal of the lower electrode, and then calculate the sample impedance. The piston applies axial stress to the sample at a downward pressure speed of 1mm / min, adjusts the air inlet and outlet to ensure constant confining pressure, and monitors the axial strain, confining pressure and applied axial stress of the sample in real time until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance is measured at this time.

[0135] ③ Change the saturation of the sample, repeat the above steps, and record the measured sample impedance, compressive strength, axial stress and axial strain.

[0136] It should be noted that, in some embodiments, step S300 may also include the following steps: measuring the compressive strength and the corresponding axial strain of each sample in the sample set in sequence through an unconfined compression test, and obtaining the impedance corresponding to each sample through an impedance analyzer based on a contact three-electrode method, so as to obtain second related data of the impedance and compressive strength of each sample; wherein, the unconfined compression test applies axial stress to the sample at a preset upper pressure speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; and synchronously and jointly measures the impedance of the sample at the corresponding moment through an impedance analyzer based on the contact three-electrode method.

[0137] For example, in some embodiments, the contact three-electrode method is combined with the unconfined compression test to measure the resistivity of the sample and the compressive strength. Figure 9a and Figure 9b As shown, ( Figure 9a and Figure 9b The corresponding meanings of the reference numerals are: 1—low-voltage electrode; 2—shielding electrode; 3—sample; 4—insulating sleeve; 5—high-voltage electrode; 6—piston). The application principle of the contact three-electrode method and the unconfined compression test combined measurement is as follows:

[0138] The three electrodes include high-voltage and low-voltage electrodes and a shielding electrode. The shielding electrode is used as the third electrode to directly introduce the surface current of the sample into the ground to eliminate its influence on the volume current measurement. The high-voltage and low-voltage electrodes apply voltage to both ends of the sample to measure the current flowing through the sample. The volume resistance of the sample is calculated by formula (1), and the equivalent area of ​​the sample is calculated according to the following formula:

[0139]

[0140] Where: D E is the diameter of the low-voltage electrode; g is the distance between the low-voltage electrode and the shielding electrode.

[0141] Finally, the resistivity ρ is solved according to the following formula:

[0142]

[0143] Where: R is the resistance, A 2 is the electrode equivalent contact area, and h is the sample thickness.

[0144] The piston can apply axial stress to the sample, and the compressive strength of the sample can be measured by the dynamometer, that is, the maximum stress that the sample can withstand before failure.

[0145] The specific experimental steps can be implemented as follows:

[0146] ① Three electrodes and an insulating sleeve constitute a sample box. Add the sample to the sample box and compact it while adding. The low-voltage electrode and the shielding electrode are connected through the insulating sleeve. After the sample fills the insulating sleeve, press the three electrodes repeatedly to ensure that the electrodes are in full contact with the sample.

[0147] ② Apply AC excitation signals of different frequencies to the high-voltage electrode and the low-voltage electrode through an impedance analyzer, and measure the output signals of the two electrodes at the same time to obtain the impedance of the sample. The piston applies axial stress to the sample at an upward pressure speed of 1mm / min until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance at this time is measured at the same time.

[0148] ③Change the saturation of the sample, repeat the above steps, and record the measured sample impedance and compressive strength.

[0149] It should be noted that, in some embodiments, step S300 may also include the following steps: measuring the compressive strength and the corresponding axial strain of each sample in the sample set in sequence through an unconfined compression test, and obtaining the impedance corresponding to each sample through an impedance analyzer based on the contact Van der Pauw method, so as to obtain second related data of the impedance and compressive strength of each sample; wherein, the unconfined compression test applies axial stress to the sample at a preset upper pressure speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the contact Van der Pauw method, the impedance of the sample at the corresponding moment is synchronously and jointly measured through an impedance analyzer.

[0150] For example, in some embodiments, the contact Van der Pauw method is combined with the unconfined compression test to measure the resistivity of the sample and the compressive strength. Fig.10a and Fig.10b As shown, ( Fig.10a and Fig.10b The corresponding meanings of the reference numerals are: 1-piston; 2-sample; 3-sample box; 4-electrode sheet). The application principle of the combined measurement of the contact Van der Pauw method and the unconfined compression test is as follows:

[0151] The Van der Pauw test principle includes measuring two voltage values ​​and two current values. Four electrodes are arranged on the surface of the sample with equal thickness. The four electrodes are named 1, 2, 3 and 4 respectively. The current value between 1 and 2 and the voltage value between 3 and 4 are measured respectively, and the resistance value R is obtained. 12,34 , the resistance value R is obtained in the same way 14,23 The relationship between the voltage and current can be expressed by the Vanderbilt formula:

[0152]

[0153] Where: d is the sample thickness, ρ is the sample resistivity.

[0154] When the sample is symmetrical and the electrodes are arranged symmetrically on the sample surface, R 12,34 =R 14,23 , the above formula can be simplified to:

[0155]

[0156] The piston applies axial stress to the sample. When the sample is damaged, the compressive strength of the sample is obtained by a dynamometer.

[0157] The specific experimental steps can be implemented as follows:

[0158] ① Four equally spaced electrodes and an insulating tube form a sample box. Add the sample into the sample box and compact it while adding.

[0159] ②Number the electrodes as 1, 2, 3 and 4, apply AC excitation signals of different frequencies to adjacent electrodes 1 and 2 through an impedance analyzer, measure the output signals of electrodes 3 and 4, then apply AC excitation signals of different frequencies to adjacent electrodes 1 and 4 pistons, measure the output signals of electrodes 2 and 3, and thus measure the impedance of the sample. Apply axial stress to the sample at a downward pressure speed of 1mm / min until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance at this time is measured and calculated.

[0160] ③Change the saturation of the sample, repeat the above steps, and record the measured sample impedance and compressive strength.

[0161] It should be noted that, in some embodiments, step S300 may also include the following steps: measuring the compressive strength and the corresponding axial strain of each sample in the sample set in turn through a triaxial test, and obtaining the impedance corresponding to each sample through an impedance analyzer based on a contact four-probe method by synchronously and jointly measuring, so as to obtain second related data of the impedance and compressive strength of each sample; wherein, the triaxial test applies axial stress to the sample at a preset downward speed, and monitors the axial strain of the sample in real time until the sample is destroyed, and obtains the axial stress and axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; and synchronously and jointly measuring the impedance of the sample at the corresponding moment through an impedance analyzer based on the contact four-probe method.

[0162] For example, in some embodiments, the contact four-probe method is combined with the triaxial test to measure the resistivity of the sample in relation to the compressive strength and compression modulus. Fig.11 As shown, ( Fig.11The corresponding meanings of the reference numerals are: 1-piston; 2-exhaust hole; 3-pressure chamber; 4-insulating sleeve; 5-sample; 6-detection probe; 7-inlet hole). The application principle of the contact two-electrode method and the triaxial test combined measurement is as follows:

[0163] In the four-probe method, four probes are arranged in a straight line and evenly spaced on the sample surface, usually equidistantly distributed. The two outer probes are used to apply a known current I, and the two inner probes are used to measure the voltage drop U generated when the current passes through the sample. Since the voltage is measured by the two inner probes, this configuration can avoid the influence of electrode contact resistance and wire resistance on the measurement results, ensuring more accurate measurements. The resistivity calculation formula is:

[0164]

[0165] Where: ρ is the resistivity of the sample, s is the spacing between adjacent probes, U is the voltage drop measured by the inner probe, and I is the current applied by the outer probe.

[0166] The compressive strength refers to the maximum stress that a sample can withstand before failure. This parameter can be obtained by a dynamometer. The compression modulus is the elastic modulus of the material and can be solved according to formula (5).

[0167] The specific experimental steps can be implemented as follows:

[0168] ① Add the sample to the insulating sleeve and compact it while adding. After the sample fills the insulating sleeve, insert four probes into the sample at equal intervals.

[0169] ② Apply AC excitation signals of different frequencies to the two outer probes through an impedance analyzer, measure the output signals of the two inner probes, and obtain the impedance of the sample. Apply axial stress to the sample at a downward pressure speed of 1 mm / min, adjust the air inlet and outlet holes to ensure constant confining pressure, monitor the axial strain, confining pressure and applied axial stress of the sample in real time until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance is measured at this time.

[0170] ③ Change the saturation of the sample, repeat the above steps, and record the measured sample impedance, compressive strength, axial stress and axial strain.

[0171] S400, based on the geometric parameters of the electrical sensor applied by the electrical measurement method combined with the impedance, obtain the resistivity corresponding to the sample in different states; the electrical measurement method includes a first electrical measurement method and a second electrical measurement method;

[0172] It should be noted that, in the embodiment of the present invention, the impedance is characterized by a resistor R.

[0173] For example, in some specific embodiments, referring to formulas (2), (7), (9) and (10) in the aforementioned specific embodiments, the geometric parameters of the electrical sensor include the electrode equivalent contact area and the spacing between adjacent probes. In some specific application scenarios, the resistivity is further calculated in combination with the sample thickness, wherein the impedance in formula (10) corresponds to U / I.

[0174] S500, based on the resistivity corresponding to the sample in different states, convert the first associated data into third associated data of the resistivity and shear strength of the sample, and convert the second associated data into fourth associated data of the resistivity and compressive strength;

[0175] S600, constructing a first correlation curve between shear strength and axial stress based on the test results of the first mechanical test, and then obtaining the internal friction angle and cohesion corresponding to the shear strength of the sample under different axial stresses according to the Coulomb shear strength theory; and then obtaining fifth correlation data of the resistivity and internal friction angle of the sample and sixth correlation data of the resistivity and cohesion according to the third correlation data;

[0176] For example, in some specific embodiments, according to Coulomb shear strength theory, the shear strength τ of the sample can be expressed as:

[0177]

[0178] Where: τ is the shear strength of the sample, c is the cohesion of the sample, and σ is the normal stress; is the internal friction angle of the sample.

[0179] S700, constructing a second correlation curve of axial strain and axial stress based on the test results of the second mechanical test, and obtaining the compression modulus corresponding to the axial strain of the sample under different axial stresses according to the slope of the second correlation curve; and then obtaining seventh correlation data of the resistivity and compression modulus of the sample according to the fourth correlation data;

[0180] For example, in some embodiments, the compression modulus is the elastic modulus of the material, which represents the ratio of the stress to the strain of the material. The compression modulus E is calculated by the linear part of the axial stress and the axial strain in the triaxial test:

[0181] Where: Δσ is the change in axial stress, and Δε is the change in axial strain.

[0182] S800, performing data fitting on the third correlation data, the fourth correlation data, the fifth correlation data, the sixth correlation data and the seventh correlation data to obtain a mechanical parameter prediction model.

[0183] Among them, the mechanical parameter prediction models include shear strength prediction model, compressive strength prediction model, internal friction angle prediction model, cohesion prediction model and compression modulus prediction model;

[0184] Among them, the mechanical parameter prediction model is used to obtain the mechanical parameters of the rock to be predicted based on the resistivity of the rock to be predicted.

[0185] For example, in some specific implementations, a mechanical parameter prediction model may be established based on the complex resistivity and mechanical parameters obtained from experiments using methods such as linear fitting, polynomial fitting, and neural network.

[0186] In order to explain the principle of the technical solution of the present invention in detail, the overall process of the present invention is described below in combination with some specific embodiments. It is easy to understand that the following is an explanation of the technical principle of the present invention and cannot be regarded as a limitation of the present invention.

[0187] First of all, it should be noted that in traditional rock mechanics research, in-situ measurement of rock mechanical parameters is difficult, and they are often measured by laboratory mechanical experiments, such as triaxial tests and unconfined compression tests. Although these methods are accurate, they are usually time-consuming and costly, especially in large-scale geological exploration or deep underground engineering, where the testing difficulty and cost are more significant. The measurement of electrical parameters of rocks is a non-invasive detection method that can quickly and economically obtain the electrical properties of rocks. The electrical parameters of rocks are affected by many factors such as mineral composition, porosity, and water content, which are also indirectly related to the mechanical properties of rocks. Therefore, the mechanical parameters of rocks can be predicted by measuring electrical parameters to reduce the cost and time of traditional experimental methods.

[0188] At present, in the research of joint electrical and mechanical measurements, there is a lack of broadband measurement methods, which limits the comprehensive understanding of the electrical properties of rocks. Broadband measurement can provide richer frequency information, thereby better reflecting the electrical response of rocks at different frequencies. However, existing studies generally do not incorporate this technology into the analysis framework. In addition, the application of non-contact measurement methods is relatively scarce, which makes the process of obtaining rock electrical parameters more cumbersome and time-consuming. Non-contact measurement has the advantages of being fast and non-destructive, and can improve the efficiency and accuracy of data acquisition. Due to the lack of application of these advanced measurement technologies, the practical application of existing research results under complex geological conditions is limited, and it is difficult to meet the needs of modern geological exploration and engineering development.

[0189] In view of the problem that current electrical and mechanical joint measurements lack broadband measurement and non-contact measurement, the present invention proposes a rock mechanical parameter prediction method based on broadband electrical parameter measurement, and establishes an accurate mechanical parameter prediction model by performing joint measurement with multiple electrical measurement methods and multiple mechanical tests.

[0190] The present invention proposes a rock mechanical parameter prediction method based on electrical parameter measurement, which comprises the following steps:

[0191] Firstly, the electrical parameter measurement method and the mechanical test combined measurement method are determined. The impedance of the hydrate-containing porous medium is obtained by applying excitation signals of different frequencies to the electrodes. The corresponding complex resistivity is calculated based on the size and distance of the electrical sensor and the impedance of the hydrate-containing porous medium. At the same time, the mechanical parameters of the hydrate-containing porous medium are measured through mechanical tests.

[0192] According to the complex resistivity and mechanical parameters obtained from the experiment, a mechanical parameter prediction model was established using linear fitting, polynomial fitting and neural network methods.

[0193] In some specific application scenarios, the establishment of a mechanical parameter prediction model can be achieved as follows:

[0194] The impedance analyzer can obtain the impedance values ​​at a series of frequency points in each state, within a certain frequency range, and calculate the corresponding complex resistivity based on the geometric size and distance of the electrical sensor and the impedance of the sample.

[0195] The shear strength and compressive strength of the sample can be directly obtained through mechanical testing, but the internal friction angle, cohesion and compression modulus cannot be directly obtained through mechanical testing.

[0196] Based on the shear strength and axial stress obtained from the ring shear test and direct shear test, the shear strength-axial stress curve is drawn. According to the Coulomb shear strength theory, the internal friction angle and cohesion can be obtained.

[0197]

[0198] Where: τ is the shear strength of the sample, c is the cohesion of the sample, σ is the normal stress, is the internal friction angle of the sample.

[0199] Based on the axial stress change and axial strain measured by the triaxial test, a stress-strain curve is drawn, and the compression modulus can be obtained according to its slope.

[0200] The complex resistivity obtained above and the mechanical parameters obtained are used to establish a mechanical parameter prediction model through linear fitting, polynomial fitting and neural network methods. The mechanical parameter prediction model specifically includes five models: internal friction angle prediction model, shear strength prediction model, cohesion prediction model, compression modulus prediction model and compressive strength prediction model. The process of establishing the mechanical parameter prediction model is as follows: Fig.12 shown.

[0201] The following uses the application scenarios of the two-electrode method (contact type) and the direct shear test combined measurement method, and the four-probe method and the compression test (triaxial test) combined measurement method as examples to specifically illustrate the logical flow of the technical solution of the present invention: 1. Specific embodiment 1:

[0203] The shear strength prediction model, internal friction angle prediction model and cohesion prediction model are established by using the two-electrode method (contact type) and direct shear test combined measurement method. The specific method is as follows:

[0204] Experimental setup:

[0205] like Figure 2 As shown, the two-electrode method (contact type) and direct shear test combined measurement system of the present invention mainly includes an impedance analyzer, upper and lower electrode plates, an insulating sleeve, a platform and a piston.

[0206] The impedance analyzer connects the upper and lower electrodes and can apply excitation signals of different frequencies to the electrodes. It can also receive the output signals of the two electrodes to obtain the impedance of the sample being tested.

[0207] The insulating sleeve is made of an insulating and elastically deformable rubber material, and together with the upper and lower electrode sheets, forms a cylindrical sample container.

[0208] The piston part is connected to the dynamometer and displacement meter, and its length should be greater than or equal to the exposed part of the sample on the platform to ensure that the exposed sample is evenly stressed and obtain accurate data.

[0209] The platform is made of a material with high hardness, insulation and smooth surface, and is mainly used to fix the sample.

[0210] The experimental operation process is:

[0211] Remove the upper electrode sheet, add hydrate-containing sediment with a saturation of 10% into the insulating sleeve, and compact it while adding. After the sample fills the insulating sleeve, cover the upper electrode sheet and press it repeatedly to ensure that the sample is in full contact with the electrode sheet.

[0212] The impedance analyzer was used to apply 1Hz-10 5 Hz excitation signal, and simultaneously detect the output signals of the two electrodes to obtain the impedance of the sample.

[0213] Place weights on the upper electrode plate and apply axial stress to the sample. The initial axial stress is 50kPa. Let the piston shear at a rate of 1mm / min. When the shear stress reading reaches a stable state or retreats significantly, it means that the sample has been sheared. It is advisable to shear until the shear deformation reaches 4mm. When the shear stress reading continues to increase, the shear deformation should reach 6mm. The shear stress at this time is the shear strength. At the same time, the sample impedance at this time is recorded by the impedance analyzer.

[0214] The saturation of the sample remains unchanged, and the weight of the weight is changed so that the axial stress applied is 100 kPa, 150 kPa and 200 kPa respectively. The above steps are repeated and the obtained shear strength and corresponding impedance are recorded.

[0215] Change the saturation of the sample, repeat the above steps, and record the measured shear strength and impedance.

[0216] Data processing and model building:

[0217] The complex resistivity of the sample is calculated based on the impedance obtained by the impedance analyzer, the size of the two electrode sheets and the spacing. 5 The value is between Hz.

[0218]

[0219] Where: |ρ| is the magnitude of complex resistivity, |Z| is the magnitude of impedance, A 1 is the effective contact area, and L is the distance between the two electrodes. The real and imaginary parts of the complex resistivity can be obtained according to the amplitude and phase angle of the complex resistivity:

[0220] ρ'=|ρ|cosθ

[0221] ρ'=|ρ|sinθ

[0222] Where: ρ' is the real part of complex resistivity, ρ" is the imaginary part of complex resistivity, and θ is the phase angle of complex resistivity.

[0223] The real and imaginary parts of the complex resistivity are fitted to the shear strength by linear fitting, polynomial fitting, neural network and other methods to obtain the best fitting equation. The results are as follows: Fig.13 , Fig.14 As shown. Fig.13 and Fig.14 It can be seen that the compressive strength increases with the increase of axial stress, and the shear strength decreases with the increase of complex resistivity under the same axial stress.

[0224] The shear strength-axial pressure curve can be drawn based on the measured shear strength and the corresponding axial pressure, and the internal friction angle and cohesion can be obtained through Coulomb shear strength theory.

[0225]

[0226] The real and imaginary parts of the complex resistivity are fitted with the internal friction angle and cohesion respectively by linear fitting, polynomial fitting, neural network and other methods to obtain the best fitting equation. The results are shown in Fig.15 , Fig.16 , Fig.17and Fig.18 shown. 2. Specific embodiment 2:

[0228] The compression modulus prediction model and compressive strength prediction model are established by using the four-probe method and compression test combined measurement method. The specific method is as follows.

[0229] Experimental setup:

[0230] like Fig.11 As shown, the four-probe method and compression test combined measurement system of the present invention mainly includes an impedance analyzer, four detection probes, an insulating sleeve, a pressure chamber and a piston.

[0231] The signal output end of the impedance analyzer is connected to the upper and lower outer probes, and excitation signals of different frequencies can be applied to the probes. Its signal receiving end is connected to the two inner test probes.

[0232] The insulating sleeve is made of insulating and elastically deformable rubber material, is cylindrical in shape, and has a lower opening which is inverted on a fixing platform.

[0233] Four detection probes are fixed on the lower platform at equal intervals.

[0234] The piston part is connected to the dynamometer and displacement meter, and its area should be greater than or equal to the cross-sectional area of ​​the insulating sleeve to ensure that the sample is evenly stressed and obtain accurate data.

[0235] The gas in the pressure chamber is controlled through the inlet and outlet holes, thereby controlling the confining pressure applied to the sample.

[0236] The experimental operation process is:

[0237] Add hydrate-containing sediments with a saturation of 10% into the insulating sleeve and compact it while adding. After the sample fills the insulating sleeve, place it on a platform with detection probes, while ensuring that the sample contacts each probe.

[0238] The impedance analyzer applied 1Hz-10 5 Hz excitation signal, and simultaneously detect the output signals of the two inner detection electrodes to obtain the impedance of the sample.

[0239] The air inlet and outlet holes are adjusted to ensure constant confining pressure. The piston applies axial stress to the sample at a downward speed of 1 mm / min. The axial strain of the sample and the applied axial stress are monitored in real time by the displacement meter and the dynamometer until the sample is destroyed. The axial stress measured at this time is the compressive strength of the sample, and the sample impedance at this time is recorded at the same time.

[0240] Change the saturation of the sample, repeat the above steps, and record the changes in compressive strength, impedance, axial strain and axial stress at each saturation.

[0241] Data processing and model building:

[0242] The complex resistivity of the sample is calculated based on the impedance obtained by the impedance analyzer, the size of the two electrode sheets and the spacing. 5 The value is between Hz.

[0243] |ρ|=2πs×|Z|

[0244] Where: |ρ| is the magnitude of complex resistivity, |Z| is the magnitude of impedance, and s is the distance between adjacent probes.

[0245] The real and imaginary parts of the complex resistivity can be obtained according to the amplitude and phase angle of the complex resistivity:

[0246] ρ'=|ρ|cosθ

[0247] ρ'=|ρ|sinθ

[0248] Where: ρ' is the real part of complex resistivity, ρ" is the imaginary part of complex resistivity, and θ is the phase angle of complex resistivity.

[0249] The real and imaginary parts of the complex resistivity are fitted to the compressive strength by linear fitting, polynomial fitting, neural network and other methods to obtain the best fitting equation. The results are as follows: Fig.19 , Fig. 20 As shown. Fig.19 and Fig. 20 It can be seen that the compressive strength increases with the increase of axial stress, and the shear strength decreases with the increase of complex resistivity under the same axial stress.

[0250] The strain-stress curve is plotted based on the measured axial strain and axial stress, and the compression modulus can be obtained by calculating the slope of the curve.

[0251] The real and imaginary parts of the complex resistivity are fitted with the compression modulus by linear fitting, polynomial fitting, neural network and other methods to obtain the best fitting equation. The results are shown in Fig.21 , Fig. 22 shown.

[0252] On the other hand, an embodiment of the present invention further provides an electronic device, the electronic device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the above-mentioned rock mechanical parameter prediction method for hydrate-containing sediments based on broadband electrical parameters when executing the computer program. The electronic device can be any intelligent terminal including a tablet computer, a car computer, etc.

[0253] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0254] The contents of the method embodiments of the present invention are all applicable to the electronic device embodiments. The functions specifically implemented by the electronic device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0255] Another aspect of an embodiment of the present invention further provides a computer-readable storage medium, wherein the storage medium stores a program, and the program is executed by a processor to implement the above method.

[0256] It should be noted that the computer-readable medium shown in the embodiment of the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (Compact Disc Read to Only Memory, CD to ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, device or device. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than computer readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0257] The contents of the method embodiments of the present invention are all applicable to the computer-readable storage medium embodiments. The functions specifically implemented by the computer-readable storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0258] The embodiment of the present invention also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of a computer device can read the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the above method.

[0259] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0260] It should be noted that, although several modules of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0261] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD to ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation of the present invention.

[0262] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0263] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features can be integrated into a single physical device and / or software module, or one or more functions and / or features can be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0264] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0265] The logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by an instruction execution device, apparatus or device (such as a computer-based device, a device including a processor, or other device that can fetch instructions from an instruction execution device, apparatus or device and execute the instructions), or in conjunction with such instruction execution device, apparatus or device. For purposes of this specification, "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution device, apparatus or device, or in conjunction with such instruction execution device, apparatus or device.

[0266] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0267] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution device. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0268] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0269] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0270] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters, characterized in that: The following steps are involved: Acquire a sample set; the sample set includes samples of hydrate-containing sediment rocks of multiple different saturations; Based on the first mechanical test, the shear strength of each sample in the sample set under different axial stresses is measured in sequence, and based on the first electrical measurement method, the impedance corresponding to each sample in different states is measured synchronously and jointly to obtain first correlation data of the impedance and the shear strength of each sample; Based on the second mechanical test, the compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence, and based on the second electrical measurement method, the impedance corresponding to each sample is simultaneously measured and obtained, so as to obtain second correlation data of the impedance and compressive strength of each sample; the compressive strength is determined based on the axial stress applied by the second mechanical test; Based on the geometric parameters of the electrical sensor applied by the electrical measurement method and the impedance, the resistivity corresponding to the sample in different states is obtained; the electrical measurement method includes the first electrical measurement method and the second electrical measurement method; Based on the resistivity corresponding to the sample in different states, converting the first associated data into third associated data of the resistivity and the shear strength of the sample, and converting the second associated data into fourth associated data of the resistivity and the compressive strength; Based on the test results of the first mechanical test, a first correlation curve between the shear strength and the axial stress is constructed, and then according to the Coulomb shear strength theory, the internal friction angle and cohesion corresponding to the shear strength of the sample under different axial stresses are obtained; and then according to the third correlation data, fifth correlation data between the resistivity and the internal friction angle of the sample and sixth correlation data between the resistivity and the cohesion are obtained; A second correlation curve of the axial strain and the axial stress is constructed based on the test result of the second mechanical test, and the compression modulus corresponding to the axial strain of the sample under different axial stresses is obtained according to the slope of the second correlation curve; and seventh correlation data of the resistivity and the compression modulus of the sample is obtained according to the fourth correlation data; Performing data fitting on the third associated data, the fourth associated data, the fifth associated data, the sixth associated data and the seventh associated data to obtain a mechanical parameter prediction model; the mechanical parameter prediction model includes a shear strength prediction model, a compressive strength prediction model, an internal friction angle prediction model, a cohesion prediction model and a compression modulus prediction model; The mechanical parameter prediction model is used to predict the mechanical parameters of the rock to be predicted based on the resistivity of the rock to be predicted.

2. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of measuring the shear strength of each sample in the sample set under different axial stresses in sequence based on the first mechanical test, and synchronously and jointly measuring the impedance of each sample under different states based on the first electrical measurement method, and obtaining first correlation data of the impedance and the shear strength of each sample, comprises the following steps: The shear strength of each sample in the sample set under different axial stresses is measured in sequence by a direct shear test, and the impedance corresponding to each sample in different states is obtained by synchronous joint measurement using an impedance analyzer based on a contact two-electrode method, so as to obtain first correlation data of the impedance and the shear strength of each sample; Among them, a single direct shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a first preset condition during the shear treatment, and the shear strength is determined based on the shear stress, and is synchronously measured by an impedance analyzer based on a contact two-electrode method.

3. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of measuring the shear strength of each sample in the sample set under different axial stresses in sequence based on the first mechanical test, and synchronously and jointly measuring the impedance of each sample under different states based on the first electrical measurement method, and obtaining first correlation data of the impedance and the shear strength of each sample, comprises the following steps: The shear strength of each sample in the sample set under different axial stresses is measured in sequence by a ring shear test, and the impedance corresponding to each sample in different states is obtained by synchronous joint measurement by an impedance analyzer based on a contact two-electrode method, so as to obtain first correlation data of the impedance and the shear strength of each sample; Among them, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a second preset condition during the shear treatment, and the shear strength is determined based on the shear stress, and is synchronously measured by an impedance analyzer based on a contact two-electrode method.

4. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of measuring the shear strength of each sample in the sample set under different axial stresses in sequence based on the first mechanical test, and synchronously and jointly measuring the impedance of each sample under different states based on the first electrical measurement method, and obtaining first correlation data of the impedance and the shear strength of each sample, comprises the following steps: The shear strength of each sample in the sample set under different axial stresses is measured in sequence by a direct shear test, and the impedance corresponding to each sample in different states is obtained by synchronous joint measurement using an impedance analyzer based on a non-contact two-electrode method, so as to obtain first correlation data of the impedance and the shear strength of each sample; Among them, a single direct shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a third preset condition during the shear treatment, and the shear strength is determined based on the shear stress, and is synchronously measured by an impedance analyzer based on a non-contact two-electrode method.

5. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of measuring the shear strength of each sample in the sample set under different axial stresses in sequence based on the first mechanical test, and synchronously and jointly measuring the impedance of each sample under different states based on the first electrical measurement method, and obtaining first correlation data of the impedance and the shear strength of each sample, comprises the following steps: The shear strength of each sample in the sample set under different axial stresses is measured in sequence by a ring shear test, and the impedance corresponding to each sample in different states is obtained by synchronous joint measurement using an impedance analyzer based on a non-contact two-electrode method, so as to obtain first correlation data of the impedance and the shear strength of each sample; Among them, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a fourth preset condition during the shear treatment, and the shear strength is determined based on the shear stress, and synchronously measured by an impedance analyzer based on a non-contact two-electrode method.

6. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of measuring the shear strength of each sample in the sample set under different axial stresses in sequence based on the first mechanical test, and synchronously and jointly measuring the impedance of each sample under different states based on the first electrical measurement method, and obtaining first correlation data of the impedance and the shear strength of each sample, comprises the following steps: The shear strength of each sample in the sample set under different axial stresses is measured in sequence by a ring shear test, and the impedance corresponding to each sample in different states is obtained by synchronous joint measurement using an impedance analyzer based on a non-contact Van der Pauw method, so as to obtain first correlation data of the impedance and the shear strength of each sample; Among them, a single ring shear test applies a fixed axial stress to the sample, and continuously shears the sample at a preset shear rate until the shear stress reaches a fifth preset condition during the shear treatment, and the shear strength is determined based on the shear stress, and a synchronous joint measurement is performed using an impedance analyzer based on the non-contact Van der Pauw method.

7. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of sequentially measuring the compressive strength and the corresponding axial strain of each sample in the sample set based on the second mechanical test, and synchronously and jointly measuring the impedance corresponding to each sample based on the second electrical measurement method, to obtain the second correlation data of the impedance and the compressive strength of each sample, comprises the following steps: The compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence through a triaxial test, and the impedance corresponding to each sample is obtained by synchronously and jointly measuring through an impedance analyzer based on a two-electrode method, so as to obtain second correlation data of the impedance and the compressive strength of each sample; Among them, the triaxial test applies axial stress to the sample at a preset downward speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and the axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the two-electrode method, the impedance of the sample at the corresponding moment is synchronously and jointly measured by an impedance analyzer.

8. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of sequentially measuring the compressive strength and the corresponding axial strain of each sample in the sample set based on the second mechanical test, and synchronously and jointly measuring the impedance corresponding to each sample based on the second electrical measurement method, to obtain the second correlation data of the impedance and the compressive strength of each sample, comprises the following steps: The compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence through an unconfined compression test, and the impedance corresponding to each sample is obtained by synchronously and jointly measuring through an impedance analyzer based on a contact three-electrode method, so as to obtain second correlation data of the impedance and the compressive strength of each sample; Among them, the unconfined compression test applies axial stress to the sample at a preset upper pressure speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and the axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the contact three-electrode method, the impedance of the sample at the corresponding moment is synchronously and jointly measured by an impedance analyzer.

9. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of sequentially measuring the compressive strength and the corresponding axial strain of each sample in the sample set based on the second mechanical test, and synchronously and jointly measuring the impedance corresponding to each sample based on the second electrical measurement method, to obtain the second correlation data of the impedance and the compressive strength of each sample, comprises the following steps: The compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence through an unconfined compression test, and the impedance corresponding to each sample is obtained by synchronously and jointly measuring through an impedance analyzer based on a contact-type Van der Pauw method, so as to obtain second correlation data of the impedance and the compressive strength of each sample; Among them, the unconfined compression test applies axial stress to the sample at a preset upper pressure speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and the axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the contact Van der Pauw method, the impedance of the sample at the corresponding moment is synchronously and jointly measured by an impedance analyzer.

10. The method for predicting rock mechanical parameters of hydrate-containing sediments based on broadband electrical parameters according to claim 1, characterized in that: The method of sequentially measuring the compressive strength and the corresponding axial strain of each sample in the sample set based on the second mechanical test, and synchronously and jointly measuring the impedance corresponding to each sample based on the second electrical measurement method, to obtain the second correlation data of the impedance and the compressive strength of each sample, comprises the following steps: The compressive strength and the corresponding axial strain of each sample in the sample set are measured in sequence by a triaxial test, and the impedance corresponding to each sample is obtained by synchronously and jointly measuring the impedance by an impedance analyzer based on a contact four-probe method, so as to obtain second correlation data of the impedance and the compressive strength of each sample; Among them, the triaxial test applies axial stress to the sample at a preset downward speed, and monitors the axial strain of the sample in real time until the sample is destroyed, obtains the axial stress and the axial strain at the corresponding moment, and uses the axial stress at the corresponding moment as the compressive strength; based on the contact four-probe method, the impedance of the sample at the corresponding moment is synchronously and jointly measured by an impedance analyzer.

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