A rock electrical property measuring device, a rock electrical property measuring method and application

Abstract

The present application belongs to the technical field of rock electrical property measuring device, and particularly relates to a rock electrical property measuring device, a rock electrical property measuring method and application. The rock electrical property measuring device comprises a T-shaped fixed rod, a sliding rod, a first electrolytic tank and a second electrolytic tank. The T-shaped fixed rod comprises a horizontal rod and a vertical rod perpendicular to the horizontal rod. The sliding rod comprises a first sliding rod, a second sliding rod and a third sliding rod. The second sliding rod is located on the left side of the vertical rod, and the first sliding rod and the third sliding rod are sequentially located on the right side of the vertical rod. The sliding rod slides along the horizontal rod. The first electrolytic tank is arranged between the second sliding rod and the vertical rod, and the second electrolytic tank is arranged between the first sliding rod and the third sliding rod. The lower end of the first sliding rod and the vertical rod is respectively connected with the first flexible electrode and the second flexible electrode arranged oppositely. The present application adopts integrated design, which not only widens the frequency bandwidth of electrical property measurement, but also improves the measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rock electrical property measuring device, and particularly relates to a rock electrical property measuring device, a rock electrical property measuring method and application. BACKGROUND

[0002] As a natural medium, rock has certain electrical properties. Different types of rock have different electrical conductivity, magnetic conductivity, polarization performance and dielectric performance. Generally, the electrical conductivity of rock is poor, but when the rock gap contains fluid with high electrical conductivity, the electrical conductivity of the rock will increase; or when the rock contains minerals with high electrical conductivity, the electrical conductivity of the rock will also increase. Therefore, the electrical properties of rock are closely related to the type, structure, porosity and fluid type of rock. Studying the electrical properties of rock plays a crucial role in geophysical exploration.

[0003] The parameters representing the electrical properties of rock mainly include resistivity, conductivity, conductance, polarization rate and dielectric constant. The main method for measuring the electrical properties of rock at present is Ohm's law method, which measures the electrical properties of rock by applying voltage to the rock and measuring the current. It mainly includes two-phase electrode method and four-phase electrode method.

[0004] The two-phase electrode method has the advantages of low cost and simple operation. The electrodes used in the two-phase electrode method for measuring the electrical properties of rock include the following schemes: 1. Using a copper rod as an electrode and a copper sulfate cotton pad as a coupling agent to form a non-polarized electrode; 2. Using lead with weak polarization ability as an electrode; 3. Using stainless steel as an electrode. The first scheme can ensure good contact between the electrode and the sample and is very stable, and the polarization phenomenon of the electrode is not obvious, but the copper sulfate solution will penetrate into the sample during measurement, changing the electrical properties of the sample. The second and third schemes have poor contact with the sample and have certain polarization phenomenon, resulting in low measurement accuracy. At the same time, since the power supply electrode and the measurement electrode are the same electrode in the two-phase electrode method, there is a coupling interference phenomenon of the signal, and the electrode polarization phenomenon is serious during low-frequency measurement, resulting in inaccurate measurement results.

[0005] When measuring rock resistivity using the four-phase electrode method, the power supply electrode and the measurement electrode are separated, which helps to eliminate the mutual interference of signals, the interference of contact resistance and the polarization phenomenon of the measurement electrode, and has better measurement stability and accuracy. However, the four-phase electrode method is complex to operate and has high cost. In high-frequency measurement, there is also a problem of mutual interference of measurement line signals, and the potential electrode needs to be deeply inserted into the sample during measurement, which changes the nature of the sample and affects the accuracy of the measurement.

[0006] Therefore, it is of great significance to provide a measurement device that can accurately measure the electrical properties of rock. SUMMARY

[0007] The present application aims to solve one or more technical problems existing in the prior art described above, and at least provide a beneficial alternative or create conditions. Specifically, the present application provides a rock electrical property measuring device with good electrical property measuring accuracy.

[0008] The inventive concept of the present application: the rock electrical property measuring device comprises a T-shaped fixed rod, a sliding rod, a first electrolytic cell, a second electrolytic cell, a first flexible electrode and a second flexible electrode.

[0009] Therefore, the first aspect of the present application provides a rock electrical property measuring device.

[0010] Specifically, the rock electrical property measuring device comprises a T-shaped fixed rod, the T-shaped fixed rod comprising a horizontal rod and a vertical rod perpendicular to the horizontal rod;

[0011] The sliding rod comprises a first sliding rod, a second sliding rod and a third sliding rod; the second sliding rod is located on the left side of the vertical rod, and the first sliding rod and the third sliding rod are sequentially located on the right side of the vertical rod, and the sliding rod slides along the horizontal rod;

[0012] The first electrolytic cell is arranged between the second sliding rod and the vertical rod, and the second electrolytic cell is arranged between the first sliding rod and the third sliding rod;

[0013] The first flexible electrode and the second flexible electrode are respectively connected to the lower ends of the first sliding rod and the vertical rod.

[0014] Preferably, the T-shaped fixed rod is a metal rod.

[0015] Preferably, the sliding rod, vertical rod are hollow metal rods, the upper end of the sliding rod is provided with a through hole, the sliding rod is connected with the horizontal rod through the through hole.

[0016] Specifically, the sliding rod is connected with the horizontal rod of the T-shaped fixed rod through the through hole, so that the sliding rod can slide horizontally along the horizontal rod.

[0017] Preferably, the upper end of the sliding rod is fixedly connected with the horizontal rod through a fixing bolt.

[0018] Specifically, when the sliding rod needs to be fixed, the fixing bolt is tightened, and when the sliding rod needs to slide left and right along the horizontal rod, the fixing bolt is loosened.

[0019] Preferably, the upper end of the first sliding rod and the vertical rod is respectively provided with a first terminal and a second terminal, the first terminal is connected with the first flexible electrode through a wire in the first sliding rod, and the second terminal is connected with the second flexible electrode through a wire in the vertical rod.

[0020] Preferably, an electrode gasket is arranged between the first flexible electrode and the first sliding rod, and between the second flexible electrode and the vertical rod.

[0021] Preferably, the lower end of the first sliding rod is provided with a connecting column at a position corresponding to the electrode gasket, and the electrode gasket is connected with the first terminal through the connecting column and a wire; the lower end of the vertical rod is provided with a connecting column at a position corresponding to the electrode gasket, and the electrode gasket is connected with the second terminal through the connecting column and a wire.

[0022] Preferably, the upper end of the second sliding rod and the third sliding rod is respectively provided with a third terminal and a fourth terminal, the third terminal is connected with the first electrolytic cell through a wire in the second sliding rod, and the fourth terminal is connected with the second electrolytic cell through a wire in the third sliding rod.

[0023] Preferably, the first terminal, the second terminal, the third terminal and the fourth terminal are respectively located on the upper end surface of the first sliding rod, the vertical rod, the second sliding rod and the third sliding rod.

[0024] Preferably, the first electrolytic cell and the second electrolytic cell each include a steel tank and a rubber layer on the inner and outer surfaces of the steel tank; the inner and outer sides of the side walls of the first electrolytic cell and the second electrolytic cell are connected through metal gaskets.

[0025] Preferably, the metal gasket is an I-shaped gasket.

[0026] Preferably, electrode pads are arranged between the vertical rod and the side wall of the first electrolytic cell, between the second sliding rod and the side wall of the first electrolytic cell, between the first sliding rod and the side wall of the second electrolytic cell, and between the third sliding rod and the side wall of the second electrolytic cell.

[0027] Preferably, the side wall of the first electrolytic cell is connected to the wire in the second sliding rod and the wire in the vertical rod through the electrode pads, respectively; and the side wall of the second electrolytic cell is connected to the wire in the first sliding rod and the wire in the third sliding rod through the electrode pads, respectively.

[0028] Preferably, a connecting column is arranged at a position corresponding to the electrode pad inside the lower end of the second sliding rod, and the electrode pad is connected to the third terminal through the connecting column and the wire in the second sliding rod in sequence; and a connecting column is arranged at a position corresponding to the electrode pad inside the lower end of the vertical rod, and the second flexible electrode is connected to the second terminal through the electrode pad, the connecting column and the wire in the vertical rod in sequence.

[0029] Preferably, a connecting column is arranged at a position corresponding to the electrode pad inside the lower end of the first sliding rod, and the first flexible electrode is connected to the first terminal through the electrode pad, the connecting column and the wire in the first sliding rod in sequence; and a connecting column is arranged at a position corresponding to the electrode pad inside the lower end of the third sliding rod, and the electrode pad is connected to the fourth terminal through the connecting column and the wire in the third sliding rod in sequence.

[0030] Preferably, the first flexible electrode and the second flexible electrode are both patch electrodes.

[0031] Preferably, the first flexible electrode and the second flexible electrode are independently selected from any one of Ag / AgCl flexible electrodes and graphene-modified carbon fiber flexible electrodes.

[0032] The present application can select Ag / AgCl flexible electrodes or graphene-modified carbon fiber flexible electrodes as electrodes for rock electrical property measurement according to the actual situation of the rock sample, so that the rock electrical property measurement is more accurate.

[0033] Preferably, the Ag / AgCl flexible electrode comprises a substrate layer, a flexible conductive layer, a silver conductive film layer and an Ag / AgCl electrode layer which are stacked in sequence; and the composition of the flexible conductive layer comprises a polydimethylsiloxane matrix and silver powder.

[0034] Preferably, the substrate layer is a silver sheet, and the surface of the silver sheet has convex points; the convex points make the mechanical coupling between the substrate layer and the flexible conductive layer of the electrode more compact.

[0035] Preferably, the composition of the flexible conductive layer comprises a polydimethylsiloxane matrix and internally doped nano-silver powder.

[0036] Specifically, for the flexible conductive layer, polydimethylsiloxane (PDMS) has the following advantages: first, the Young's modulus is low, with good flexibility and stretchability; second, it has strong corrosion resistance, good transparency and stability in a wide range of use temperatures, and can be used as a substrate material for large-area transparent flexible electronic devices or thermal stability devices; third, it is easy to combine with electronic materials, allowing the electrode material to be fixed on its surface, and the PDMS can be prepared into a structure with a certain geometric shape as needed to improve its ductility and meet the coplanar structure requirements; fourth, the preparation process is simple and easy to operate. In addition, after doping nano-silver powder in the PDMS, the PDMS has good flexibility and conductivity.

[0037] Preferably, the silver conductive film layer is a silver foil.

[0038] Preferably, the Ag / AgCl electrode layer has a porous structure, and the composition of the Ag / AgCl electrode layer includes Ag particles and AgCl particles.

[0039] Preferably, the Ag / AgCl electrode in the Ag / AgCl electrode layer is a non-polarizable electrode.

[0040] Specifically, the porous structure allows the Ag / AgCl electrode layer to have a larger specific surface area, greatly increasing the contact area between the electrode and the rock sample; and the non-polarization characteristics of the Ag / AgCl electrode can greatly reduce the measurement error caused by electrode polarization during measurement, improving the accuracy of the test.

[0041] Preferably, the preparation method of the Ag / AgCl flexible electrode comprises the following steps:

[0042] (1) preparing a nano Ag / AgCl suspension;

[0043] (2) immersing a silver foil in the nano Ag / AgCl suspension obtained in step (1), drying to obtain an electrode embryo, and then sintering to form a porous Ag / AgCl electrode on the silver foil, thereby obtaining a silver conductive film with an Ag / AgCl electrode layer attached;

[0044] (3) placing the electrode substrate at the bottom of a mold, adding PDMS liquid prepolymer into the mold, then placing the silver conductive film with the Ag / AgCl electrode layer attached on the surface of the PDMS liquid prepolymer, curing, demolding, and obtaining an Ag / AgCl flexible electrode.

[0045] Preferably, in step (1), the preparation process of the nano Ag / AgCl suspension is as follows:

[0046] S1: adding AgNO3 into a polyvinylpyrrolidone (PVP) solution to obtain a PVP-AgNO3 solution;

[0047] S2: adding a saturated sodium chloride solution into the PVP-AgNO3 solution to obtain a PVP-AgCl dispersion system;

[0048] S3: adding nano silver powder into the PVP-AgCl dispersion system to obtain a PVP-Ag / AgCl dispersion system, thereby obtaining the nano Ag / AgCl suspension.

[0049] Preferably, in step (2), after drying, the obtained product is repeatedly immersed into the nano Ag / AgCl suspension until a uniform and dense PVP-Ag / AgCl is attached to the surface of the silver foil, thereby obtaining an electrode embryo.

[0050] Preferably, in step (2), after forming the porous Ag / AgCl electrode on the silver foil, the silver conductive film with the Ag / AgCl electrode layer attached thereto is obtained after washing and drying.

[0051] Preferably, in step (3), the silver powder, PDMS and curing agent are mixed to obtain a PDMS liquid prepolymer.

[0052] Preferably, the mass ratio of the silver powder, PDMS and curing agent is (4-6):(8-12):1; further preferably, the mass ratio of the silver powder, PDMS and curing agent is (4.5-5.5):(9-11):1; more preferably, the mass ratio of the silver powder, PDMS and curing agent is 5:10:1.

[0053] Preferably, in step (3), the curing temperature is 50-70℃ and the curing time is 0.8-1.2h; further preferably, in step (3), the curing temperature is 55-65℃ and the curing time is 0.9-1.1h; more preferably, in step (3), the curing temperature is 60℃ and the curing time is 1h.

[0054] Preferably, in step (3), the electrode substrate is prepared by using a stamping machine with protrusions to press protrusions on the surface of the silver sheet, thereby obtaining the electrode substrate.

[0055] Specifically, the protrusions are closely arranged.

[0056] Specifically, the application uses the infiltration pulling method to produce the Ag / AgCl flexible electrode as the rock electrical property measuring electrode, when preparing the flexible conductive layer, the PDMS material is used as the flexible substrate, and the nano silver powder is doped in the PDMS material as the conductive channel, the flexibility of the PDMS is reserved, and the conductivity of the substrate is enhanced; when preparing the Ag / AgCl electrode layer, the sol-gel method of the PVP system is used, the PVP is used as the dispersant to prevent the AgCl from agglomerating, the AgCl particle size generated in the reaction is small and uniformly dispersed, the PVP is used as the adhesive to make the nano Ag powder and the AgCl uniformly mixed, and the PVP is used as the pore-forming agent to make the Ag / AgCl electrode layer after sintering have small and dense small pores, so that the specific surface area of the electrode layer is increased. The Ag / AgCl electrode layer is attached to the silver conductive film by using the infiltration pulling method, the electrode layer is thick and dense, and the service life of the electrode can be improved. The material of the Ag / AgCl electrode layer is selected as Ag and AgCl, a non-polarized electrode is formed during the measurement, the measurement error caused by the electrode polarization is greatly reduced, and the measurement precision is improved.

[0057] Preferably, the graphene modified carbon fiber flexible electrode comprises a substrate layer, a flexible conductive layer, a carbon fiber conductive film and a graphene modified carbon fiber electrode layer which are sequentially stacked; and the flexible conductive layer comprises a polydimethylsiloxane matrix and silver powder.

[0058] Preferably, the substrate layer and the flexible conductive layer of the Ag / AgCl flexible electrode are the same as the substrate layer and the flexible conductive layer of the graphene modified carbon fiber flexible electrode.

[0059] Preferably, the flexible conductive layer comprises a polydimethylsiloxane matrix and internally doped nano silver powder.

[0060] Preferably, the preparation process of the graphene modified carbon fiber flexible electrode comprises the following steps:

[0061] (1) immersing carbon fiber sheets in an acetone solution, ultrasonic cleaning, drying, polishing the surface, and obtaining a carbon fiber conductive film;

[0062] (2) using the carbon fiber conductive film obtained in step (1) as a positive electrode, a stainless steel plate as a negative electrode, and then placing the whole in a graphene oxide dispersion solution to perform electrophoretic deposition, obtaining a graphene oxide modified carbon fiber electrode layer, and then reducing in a nitrogen environment to obtain a graphene modified carbon fiber electrode layer;

[0063] (3) placing the electrode substrate at the bottom of a mold, adding PDMS liquid prepolymer into the mold, then placing the graphene modified carbon fiber conductive film on the surface of the PDMS liquid prepolymer, curing, demolding, and obtaining a graphene modified carbon fiber flexible electrode.

[0064] Preferably, the method for preparing the carbon fiber conductive film comprises the following steps: immersing a carbon fiber sheet into an acetone solution, ultrasonic cleaning to obtain a desludged carbon fiber sheet, and then drying and polishing the surface of the carbon fiber sheet to make it rough, thereby obtaining the carbon fiber conductive film.

[0065] Preferably, in step (2), the electrophoretic deposition is performed under ultrasonic conditions.

[0066] Preferably, in step (2), the graphene-modified carbon fiber conductive film is first stabilized under an air pump and then reduced in a nitrogen environment.

[0067] Preferably, the stabilization temperature is 240-330℃, and the stabilization time is 1.5-2.5h; further preferably, the stabilization temperature is 260-300℃, and the stabilization time is 1.8-2.2h; more preferably, the stabilization temperature is 280℃, and the stabilization time is 2h.

[0068] Preferably, the reduction temperature is 600-800℃, and the reduction time is 4-6min; further preferably, the reduction temperature is 650-750℃, and the reduction time is 4.5-5.5min; more preferably, the reduction temperature is 700℃, and the reduction time is 5min.

[0069] Preferably, in step (3), the electrode substrate, the PDMS liquid prepolymer, and the preparation method are the same as the Ag / AgCl flexible electrode.

[0070] Specifically, carbon fiber has the characteristics of light weight, corrosion resistance, and high strength, and as an electrode material, carbon fiber has weak background current and rich surface activity, strong adaptability, wide detection range, and can be made into different types of fiber fabric according to different needs, greatly expanding the use range of carbon fiber as an electrode. The surface of the carbon fiber electrode prepared by the electrochemical modification method is attached with graphene, and the deposition of graphene on the surface of the carbon fiber can increase the specific surface area and surface roughness of the carbon fiber, so that the interface bonding area of the carbon fiber and the test sample can be more effectively increased, and the coupling resistance of the flexible electrode and the substrate (test sample) can be reduced. In addition, graphene can increase the active functional groups and chemical activity on the surface of carbon fiber, so that the carbon fiber and the substrate are connected in a chemical bonding manner, and the mechanical interlocking force of the electrode and the measured sample interface is enhanced. In summary, using the chemically modified carbon fiber electrode as a rock electrical property measuring electrode, while retaining the advantages of carbon fiber, such as good mechanical strength, strong heat resistance and corrosion resistance, as well as weak background current and rich surface activity as an electrode material, the graphene-modified carbon fiber also makes up for the shortcomings of poor conductivity and poor anti-interference ability of carbon fiber, making the rock electrical property measurement more accurate.

[0071] Specifically, the present application can select corresponding electrodes according to the actual situation of the rock sample. For the rock sample with small porosity, a graphene modified carbon fiber flexible electrode can be selected, which can increase the contact area and reduce the contact resistance. For the rock sample with large porosity or high surface roughness, an Ag / AgCl flexible electrode can be selected, which can reduce the polarization degree or contact resistance of the electrode and ensure the accuracy of the measurement.

[0072] The second aspect of the present application provides a rock electrical property measurement method.

[0073] Specifically, the rock electrical property measurement method adopts the rock electrical property measurement device of the first aspect of the present application to perform two-phase electrode measurement and / or four-phase electrode measurement.

[0074] The two-phase electrode measurement method comprises the following steps:

[0075] The two end faces of the rock sample are respectively attached to the first flexible electrode and the second flexible electrode, then the second terminal is connected to the voltage end of the measuring instrument, the first terminal is connected to the current end of the measuring instrument, and the measurement is performed.

[0076] The four-phase electrode measurement method comprises the following steps:

[0077] The two end faces of the rock sample are respectively attached to the first flexible electrode and the second flexible electrode, then the third terminal and the fourth terminal are connected to the voltage end of the measuring instrument, the first terminal and the second terminal are connected to the current end of the measuring instrument, and the measurement is performed.

[0078] Preferably, when the rock sample is installed, the fixing bolts are loosened, the two end faces of the rock sample are respectively attached to the first flexible electrode and the second flexible electrode, and after complete attachment, the fixing bolts are tightened, so that the first flexible electrode and the second flexible electrode clamp the rock sample.

[0079] Specifically, the two-phase electrode measurement method and the four-phase electrode measurement method both measure the contact resistance, resistivity, electrode polarization rate and impedance spectrum of the rock sample, and when the two-phase electrode measurement method is used to measure the impedance spectrum of the rock sample, the frequency range is 1Hz-10MHz, and when the four-phase electrode measurement method is used to measure the impedance spectrum of the rock sample, the frequency range is 1MHz-10kHz.

[0080] Preferably, when the two-phase electrode measurement method and the four-phase electrode measurement method are combined, the two-phase electrode measurement method is performed first, and then the four-phase electrode measurement method is performed.

[0081] Preferably, the measuring instrument comprises any one of a multimeter and an impedance analyzer.

[0082] Preferably, for large-scale rocks in the field, an array electrode measurement scheme can be used for multi-point measurement.

[0083] The third aspect of the present application provides a rock electrical property measurement device according to the first aspect of the present application in the field of rock measurement.

[0084] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0085] (1) The rock electrical property measurement device of the present application adopts an integrated design, i.e., the two-phase electrode method and the four-phase electrode method are combined in the same device for measuring the electrical properties of rocks. When measuring rock samples, the four-phase electrode method can be selected for low-frequency measurement, the two-phase electrode method can be selected for high-frequency measurement, and the two-phase electrode method and the four-phase electrode method can be combined for wideband measurement, which greatly widens the frequency band of rock electrical property measurement and improves the measurement accuracy.

[0086] (2) The measurement device of the present application adopts a full-metal shell design, and the metal shell, the measurement electrode, and the measurement instrument are commonly grounded during measurement, which reduces signal interference and improves measurement accuracy.

[0087] (3) The present application can select Ag / AgCl flexible electrode or graphene-modified carbon fiber flexible electrode as the electrode for rock electrical property measurement according to the actual situation of the rock sample, making the rock electrical property measurement more accurate and flexible. In addition, when using the four-electrode method, different materials of metal gaskets can be selected according to different electrolytes, for example, copper gaskets can be selected when the electrolyte solution is CuSO4, and silver gaskets can be selected when the electrolyte solution is KCl or NaCl. That is, the present application can provide different measurement electrodes and measurement schemes, which can be selected according to the actual measurement conditions and measurement requirements, making the measurement device have higher applicability.

[0088] (4) The present application adopts a flexible patch electrode design, which can still use flexible electrodes to attach to the surface of the rock sample for measurement in field environments or environments without conditions for preparing rock samples. For large-scale rocks in the field, an array electrode measurement scheme can be used for multi-point measurement, which can comprehensively understand the real-time electrical property characteristics of the rock, realize the internal imaging of the rock through subsequent data processing, and further grasp the overall characteristics of the rock electrical property. BRIEF DESCRIPTION OF DRAWINGS

[0089] Figure 1 Figure 1 is a schematic diagram of a rock electrical property measurement device according to an embodiment of the present application;

[0090] Figure 2 Figure 2 is a schematic diagram of an Ag / AgCl flexible electrode according to an embodiment of the present application;

[0091] Figure 3 Structure diagram of the first electrolytic cell and the second electrolytic cell in Example 1 of the present application;

[0092] Figure 4 Structure diagram of the rock electrical property measuring device in Example 1 of the present application when measured by the two-phase electrode method;

[0093] Figure 5 Structure diagram of the rock electrical property measuring device in Example 1 of the present application when measured by the four-phase electrode method;

[0094] Figure 6 Structure diagram of the graphene-modified carbon fiber flexible electrode in Example 2 of the present application;

[0095] Figure 7 Contact resistance results of rock samples with different water contents measured by the rock electrical property measuring device in Example 1 and Comparative Example 1 of the present application;

[0096] Figure 8 Actual resistivity and error of measured resistivity of rock samples with different water contents measured by the rock electrical property measuring device in Example 1 and Comparative Example 1 of the present application;

[0097] Figure 9 Results of the two-phase electrode method and the four-phase electrode method for measuring rock samples by the rock electrical property measuring device in Example 1 of the present application;

[0098] Figure 10 Array electrode measurement schematic diagram.

[0099] Wherein, 1 is a T-shaped fixed rod, 2 is a first sliding rod, 3 is a second sliding rod, 4 is a third sliding rod, 5 is a fixed bolt, 6 is a spring, 7 is a first wiring terminal, 8 is a second wiring terminal, 9 is a third wiring terminal, 10 is a fourth wiring terminal, 11 is an electrode gasket, 12 is a wire, 13 is a connecting column, 14 is an Ag / AgCl flexible electrode, 15 is a first electrolytic cell, 16 is a second electrolytic cell, 17 is an electrode substrate, 18 is a flexible conductive layer, 19 is a silver conductive film, 20 is a porous Ag / AgCl electrode layer, 21 is a nano Ag particle, 22 is an AgCl particle, 23 is a steel tank, 24 is a rubber shell, 25 is a metal gasket, 26 is a rock sample, 27 is an electrode substrate, 28 is a flexible conductive layer, 29 is a carbon fiber conductive film, and 30 is a graphene-modified carbon fiber electrode layer. DETAILED DESCRIPTION

[0100] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0101] The raw materials, reagents or devices used in the following examples, if not specifically stated, can be obtained from conventional commercial channels or can be obtained by known existing methods.

[0102] The schematic diagram of the rock electrical property measuring device in Example 1 of the present application is shown in Figure 1 The schematic diagram of the structure of the Ag / AgCl flexible electrode is shown in Figure 2 Figure 2 In Figure (a) of the above, the schematic diagram of the structure of the Ag / AgCl flexible electrode is shown, Figure 2 In Figure (b) of the above, the enlarged view of the Ag / AgCl electrode layer in Figure (a) is shown; and the schematic diagram of the structure of the first electrolytic cell and the second electrolytic cell is shown in Figure 3

[0103] Example 1

[0104] As shown in Figure 1 , 2 , 3, a rock electrical property measuring device comprises a T-shaped fixing rod 1 for fixing, a first sliding rod 2, a second sliding rod 3 and a third sliding rod 4 for clamping,

[0105] The T-shaped fixing rod 1 (stainless steel) comprises a horizontal rod and a vertical rod perpendicular to the horizontal rod; the first sliding rod 2, the second sliding rod 3 and the third sliding rod 4 are all hollow metal rods (stainless steel); the second sliding rod 3 is located on the left side of the vertical rod, and the first sliding rod 2 and the third sliding rod 4 are sequentially located on the right side of the vertical rod; the upper end of each of the first sliding rod 2, the second sliding rod 3 and the third sliding rod 4 is provided with a through hole, and the first sliding rod 2, the second sliding rod 3 and the third sliding rod 4 are sleeved on the horizontal rod through the through holes and can slide horizontally along the horizontal rod, and the first sliding rod 2, the second sliding rod 3, the third sliding rod 4 and the horizontal rod are fixed by fixed bolts 5 respectively;

[0106] A spring 6 is arranged between the first sliding rod 2 and the vertical rod, between the second sliding rod 3 and the vertical rod, and between the third sliding rod 4 and the first sliding rod 2 respectively;

[0107] The upper end surface of each of the first sliding rod 2, the second sliding rod 3, the third sliding rod 4 and the vertical rod is respectively provided with a first wiring terminal 7, a third wiring terminal 9, a fourth wiring terminal 10 and a second wiring terminal 8; the inner and outer surfaces of the lower end of the first sliding rod 2 and the vertical rod, and the inner surfaces of the lower ends of the second sliding rod 3 and the third sliding rod 4 are all provided with electrode pads 11; the interiors of the first sliding rod 2, the second sliding rod 3, the third sliding rod 4 and the vertical rod are all provided with wires 12, and the lower interiors corresponding to the electrode pads 11 are all respectively provided with connecting columns 13; the electrode pads 11 are connected with the first wiring terminal 7, the second wiring terminal 8, the third wiring terminal 9 and the fourth wiring terminal 10 through the corresponding connecting columns 13 and wires 12 respectively; ​​

[0108] The Ag / AgCl flexible electrode 14 is arranged on the electrode pad 11 of the first sliding rod 2 and the vertical rod respectively, and the two Ag / AgCl flexible electrodes are arranged oppositely; the Ag / AgCl flexible electrode 14 on the first sliding rod 2 is connected with the first wiring terminal 7 through the electrode pad 11, the connecting column 13 and the wire 12 in sequence; the Ag / AgCl flexible electrode 14 on the vertical rod is connected with the second wiring terminal 8 through the electrode pad 11, the connecting column 13 and the wire 12 in sequence;

[0109] The Ag / AgCl flexible electrode 14 on the first sliding rod 2 and the vertical rod is attached to the two ends of the rock sample, and the position of the first sliding rod 2 is adjusted left and right so that the two Ag / AgCl flexible electrodes 14 clamp the rock sample;

[0110] The first electrolytic tank 15 is arranged between the second sliding rod 3 and the vertical rod, and the second electrolytic tank 16 is arranged between the first sliding rod 2 and the third sliding rod 4;

[0111] The Ag / AgCl flexible electrode 14 comprises an electrode base 17, a flexible conductive layer 18, a silver conductive film 19 and a porous Ag / AgCl electrode layer 20 arranged in sequence; the electrode base 17 is a silver sheet with dense convex points on the surface, the flexible conductive layer 18 is polydimethylsiloxane doped with nano silver powder, the silver conductive film 19 is silver foil, and the Ag / AgCl electrode layer 20 is composed of nano Ag particles 21 and AgCl particles 22;

[0112] The first electrolytic tank 15 and the second electrolytic tank 16 are both made of steel material, and the base body is a steel tank 23; the inner and outer sides of the steel tank 23 are wrapped with a layer of rubber shell 24, and the inner and outer sides of the side wall of the first electrolytic tank 15 and the second electrolytic tank 16 are connected through an I-shaped metal gasket 25.

[0113] The preparation method of the Ag / AgCl flexible electrode 14 comprises the following steps:

[0114] (1) Preparation of nano Ag / AgCl suspension liquid:

[0115] S1: 10g of polyvinylpyrrolidone (PVP) is dissolved in 100mL of 75% ethanol solution, and the PVP is continuously stirred until it is completely dissolved, the molecular weight of the PVP is 1300000, and a mixed solution is obtained;

[0116] S2: 20g of silver nitrate (AgNO3) is added to the mixed solution of step S1, and the stirring is continued until the silver nitrate is completely dissolved, and a PVP-AgNO3 solution is obtained, which is slightly brown at this time;

[0117] S3: At room temperature, 8 g (excess) of sodium chloride was dissolved in 19 g of water under continuous stirring until the sodium chloride was completely dissolved, to obtain a saturated sodium chloride solution;

[0118] S4: The saturated sodium chloride solution obtained in step S3 was slowly added to the ultrasonically stirred PVP-AgNO3 solution, and after the addition was completed, ultrasonic stirring was continued for 4 hours to allow the sodium chloride to completely react with the silver nitrate to form silver chloride, to obtain a PVP-AgCl dispersion system, which was milky white at this time;

[0119] S5: Under ultrasonic stirring, 15 g of nano-silver powder (5 nm) was slowly added to the PVP-AgCl dispersion system to obtain a PVP-Ag / AgCl dispersion system, and the stirring was continued until the silver powder was uniformly dispersed to obtain a nano-Ag / AgCl suspension, which was blackish gray at this time;

[0120] (2) Preparation of electrode embryo by infiltration pulling method:

[0121] S6: A 0.1 mm thick silver foil was cut into a 5 cm diameter disc;

[0122] S7: Under ultrasonic conditions, the silver foil was completely immersed in the nano-Ag / AgCl suspension, and after 5 seconds, it was taken out and placed in a hot air oven at 60°C for drying for 30 min;

[0123] S8: The dried silver foil was again immersed in the nano-Ag / AgCl suspension, and step S7 was repeated for a total of 10 times until the silver foil surface was attached with uniform and dense dried PVP-Ag / AgCl, to obtain an electrode embryo;

[0124] (3) Preparation of silver conductive film with Ag / AgCl electrode layer attached:

[0125] S9: The electrode embryo was placed in a muffle furnace and heated to 400°C at a heating rate of 1.5°C / min, and sintered for 120 min to burn off the PVP and make the Ag / AgCl on the surface of the silver foil porous, to obtain a porous electrode;

[0126] S10: The porous electrode was placed in 20% mass fraction dilute hydrochloric acid for 180 min to remove the excess NaCl in step S3 and impurities introduced during the production process, to obtain an acid-washed electrode; the acid-washed electrode was washed in clean water for 10 min to obtain a washed electrode; the washed electrode was placed in a hot air oven at 60°C for drying for 30 min, to obtain a silver conductive film with Ag / AgCl electrode layer attached;

[0127] (4) Preparation of flexible conductive layer and Ag / AgCl flexible electrode:

[0128] S11: 20 grams of PDMS main agent (PDMS) was weighed in a beaker, 10 g of silver powder with a particle size of 50 nm was added, and magnetic stirring was performed for 24 h to make the silver powder fully dispersed in the PDMS main agent to obtain a dispersion system; 2 grams of PDMS curing agent (platinum gold catalyst) was added to the dispersion system, and stirring was performed for 1 hour to make the curing agent fully mixed with the main agent to obtain a PDMS liquid prepolymer;

[0129] S12: A 1mm thick silver plate was cut into a silver sheet with a diameter of 5cm, a stamping machine with convex points was used to press a large number of convex points on the surface of the silver sheet to obtain an electrode substrate; the electrode substrate was placed at the bottom of the mold, and then the PDMS liquid prepolymer was poured into the mold, and the mold was placed in a vacuum drying box for 1h to eliminate the bubbles in the PDMS liquid prepolymer; then the silver conductive film with Ag / AgCl electrode layer was placed on the surface of the PDMS liquid prepolymer, and the whole mold was placed in a drying box at 60°C for 1h to make the electrode solidify, and after complete solidification, the mold was removed to obtain an Ag / AgCl flexible electrode.

[0130] The following uses the rock electrical property measuring device of Example 1 to measure the electrical property of the rock, taking the marble with a relatively smooth surface as an example, first, the marble rock sample is cut into a cylindrical sample with a diameter of 5cm, and then the sample is soaked in water for 24h, and then the surface water is wiped dry, and the side is covered with waterproof tape to prevent water evaporation from causing changes in the parameters of the rock during measurement; after the rock sample is prepared, the Ag / AgCl flexible electrode 14 is taken out from the NaCl solution and is respectively attached to the electrode pads 11 on the vertical rod and the lower end of the first sliding rod 2.

[0131] For two-phase electrode method measurement, the fixing bolt 5 on the first sliding rod 2 is loosened, the first sliding rod 2 is slid away from the T-shaped fixed rod 1, the bottom surface of the rock sample 26 is completely attached to the flexible electrode 14 on the vertical rod, and then the fixing bolt 5 is tightened to completely clamp the rock sample 26 with the flexible electrode 14 at the lower end of the vertical rod and the flexible electrode 14 at the lower end of the first sliding rod 2; then the terminal 7 is connected to the current terminal of the measuring instrument (digital multimeter), and the terminal 8 is connected to the voltage terminal of the measuring instrument (digital multimeter), and the contact resistance, resistivity, electrode polarization rate and impedance spectrum of the rock sample 26 are measured, respectively; when the impedance spectrum is measured using this method, the frequency range is 1Hz-10MHz.

[0132] For the four-phase electrode method measurement, according to the electrolyte saturated potassium chloride solution, the appropriate metal pad 25 is selected as a copper sheet, and is installed on the first electrolytic cell 15 and the second electrolytic cell 16, on the basis of the two-phase method measurement, the fixing bolt 5 at the upper end of the second sliding rod 3 is loosened, and the second sliding rod 3 is slid to be away from the vertical rod of the T-shaped fixed rod 1, the first electrolytic cell 15 is installed between the second sliding rod 3 and the lower end of the vertical rod, and the electrode pad 11 at the lower end of the second sliding rod 3 and the vertical rod is completely attached to the metal pad 25 of the first electrolytic cell, and then the fixing bolt 5 at the upper end of the second sliding rod 3 is tightened; the installation of the second electrolytic cell 16 is the same as that of the first electrolytic cell 15; after the installation of the first electrolytic cell 15 and the second electrolytic cell 16, the electrolyte (saturated potassium chloride solution) is poured into the first electrolytic cell 15 and the second electrolytic cell 16 respectively, so that the electrolyte completely covers the metal pad 25; then the wires of the measuring instrument are connected with the terminal respectively, wherein the third terminal 9 and the fourth terminal 10 are connected with the voltage end of the measuring instrument (digital multimeter) respectively, the first terminal 7 and the second terminal 8 are connected with the current end of the measuring instrument (digital multimeter) respectively, and then the measurement is performed, and the contact resistance, the resistivity and the impedance spectrum of the rock sample 26 are measured respectively. When the impedance spectrum is measured by using the method, the frequency range is 1MHz-10kHz.

[0133] The schematic diagrams of the measuring devices in the two-phase electrode method and the four-phase electrode method are shown in Figure 4 、 5

[0134] For the four-phase electrode method measurement, after the measurement is completed, the first electrolytic cell 15 and the second electrolytic cell 16 need to be removed, and the electrolyte in the electrolytic cells is poured into a waste liquid pool, washed with clean water and dried, the metal pad 25 on the side wall is unscrewed, washed and dried, and the Ag / AgCl flexible electrode 14 is removed and placed in a NaCl solution to ensure the electrode activation.

[0135] Example 2

[0136] The difference between example 2 and example 1 is that the graphene modified carbon fiber flexible electrode in example 2 replaces the Ag / AgCl flexible electrode 14 in example 1, and the rock in example 2 is red sandstone, and the others are the same as in example 1.

[0137] The graphene modified carbon fiber flexible electrode in example 2 includes an electrode substrate 27, a flexible conductive layer 28, a carbon fiber conductive film 29 and a graphene modified carbon fiber electrode layer 30 arranged in sequence; the electrode substrate 27 and the flexible conductive layer 28 are the same as the electrode substrate and the flexible conductive layer in the Ag / AgCl flexible electrode in example 1.

[0138] The structure schematic diagram of the graphene modified carbon fiber flexible electrode in example 2 of the present application is shown in Figure 6 .​

[0139] The preparation method of the graphene modified carbon fiber flexible electrode comprises the following steps:

[0140] (1) Preparation of carbon fiber conductive film: cut the carbon fiber sheet with a thickness of 0.1 mm into a circular sheet with a diameter of 5 cm, ultrasonically clean the circular carbon fiber sheet in an acetone solution for 1 h to obtain a desized carbon fiber sheet; wash the carbon fiber sheet with deionized water and dry it in an oven at 85°C; then polish the surface of the carbon fiber sheet to make it rough to obtain a carbon fiber conductive film;

[0141] (2) Preparation of graphene oxide:

[0142] S1: Assemble a 250 mL reaction bottle in an ice water bath, add 115 mL of concentrated nitric acid and stir to obtain a reactant A (concentrated nitric acid); add 5 g of graphite powder, 2.5 g of sodium nitrate and 15 g of potassium permanganate in sequence in the reactant A and continuously stir, control the reaction temperature below 20°C, after the reaction is completed, warm up to 35°C, continue to stir for 30 min; then add an appropriate amount of deionized water, continue to stir for 20 min, then add hydrogen peroxide until the solution turns bright yellow, filter the reactant to obtain a precipitate B and a filtrate C;

[0143] S2: Add excess barium chloride solution to the filtrate C until no new precipitate is generated in the filtrate C; wash the precipitate B with a dilute nitric acid solution, wash the precipitate B with deionized water, and then dry to obtain graphene oxide;

[0144] (3) Preparation of graphene oxide dispersion: take 50 mg of graphene oxide and disperse it in 500 mL of isopropanol, ultrasonically treat at room temperature for 1 h to obtain a graphene oxide dispersion;

[0145] (4) Electrophoretic deposition of graphene oxide: use the carbon fiber conductive film as the positive electrode and a stainless steel plate as the negative electrode, then place them in the graphene oxide dispersion, apply an external voltage of 17 V, and electrophoretically deposit graphene oxide under ultrasonic condition to obtain a graphene oxide modified carbon fiber electrode layer;

[0146] (5) Reduction of graphene oxide: place the graphene oxide modified carbon fiber electrode layer under an air pump at 280°C for 2 h to stabilize the material, and then reduce the stabilized material under a nitrogen pump at a temperature of 700°C for 5 min to reduce the graphene oxide to graphene to obtain a graphene modified carbon fiber electrode layer;

[0147] (6) Preparation of flexible conductive layer and graphene modified carbon fiber flexible electrode: use the same method as step (4) in the preparation process of Ag / AgCl flexible electrode to obtain a graphene modified carbon fiber flexible electrode.

[0148] Comparative Example 1

[0149] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses a Cu electrode instead of the Ag / AgCl flexible electrode 14 in Example 1, while the rest is the same as in Example 1.

[0150] Measurement results

[0151] The impedance of rock samples with different moisture contents (0.83%, 1.01%, 2%, 2.94%, 4.36%) was measured by connecting a digital multimeter to terminals 7, 8, 9, and 10 of the rock electrical property measuring device of Example 1 and Comparative Example 1. The measurements were taken 100 times consecutively, and the arithmetic mean of the measurement data was used as the measurement result.

[0152] In the measurement, contact resistance is included in the results. Therefore, it is necessary to measure the contact resistance between the rock sample and the electrode to correct the measured resistance. Rock cores with the same dry density are prepared into rock samples with the same cross-sectional area and lengths of 2, 4, 6, 8, and 10 cm, respectively. In this case, the resistance of the rock sample is directly proportional to the length of the rock sample.

[0153] R = k·L (1);

[0154] In equation (1), R is the resistance of the rock sample, L is the length of the rock sample, and k is the proportionality coefficient. Due to the introduction of contact resistance, the measured resistance of the rock sample is linearly related to its length.

[0155] R m =k·L+R c (2);

[0156] In equation (2), R m and R c Let represent the measured resistance and the contact resistance, respectively. According to equation (2), a linear equation between the measured resistance and the length of the rock sample is fitted, and its intercept is the contact resistance.

[0157] The standard resistivity expression for a rock sample is:

[0158]

[0159] In equation (3), ρ 18 Let S be the resistivity of the sample at 18℃, S be the cross-sectional area of ​​the rock sample along the direction of current, and α be the experimental constant, typically 0.025℃. -1 T represents the experimental temperature, and R represents the measured resistance. m With contact resistance R c The difference between them represents the corrected resistance, while the original resistivity of the contact resistance is:

[0160]

[0161] In equation (4), ρ m This represents the resistivity before contact resistance correction.

[0162] Resistivity error is used to represent the error before and after resistivity correction:

[0163]

[0164] In equation (5), E ρ This represents resistivity error.

[0165] The contact resistance results of rock samples with different water contents measured by the measuring device in Example 1 and Comparative Example 1 are as follows: Figure 7 As shown, where, Figure 7 Figure (a) shows a schematic diagram of contact resistance measurement and calculation. Figure 7 Figure (b) shows the contact resistance diagram of a rock sample with a water content of 0.83% (w = 0.83%) measured by the measuring device of Example 1 and Comparative Example 1. Figure 7 Figure (c) shows the contact resistance diagram of a rock sample with a water content of 1.01% (w = 1.01%), measured by the measuring device of Example 1 and Comparative Example 1. Figure 7 Figure (d) shows the contact resistance diagram of a rock sample with a water content of 2% (w = 2%), measured by the measuring device of Example 1 and Comparative Example 1. Figure 7 Figure (e) shows the contact resistance diagram of a rock sample with a water content of 2.94% (w = 2.94%) measured by the measuring device of Example 1 and Comparative Example 1. Figure 7 Figure (f) shows the contact resistance diagram of a rock sample with a water content of 4.36% (w = 4.36%) measured by the measuring device of Example 1 and Comparative Example 1. The horizontal axis, Length, represents the length of the rock sample, and the vertical axis, Resistance, represents the contact resistance. cm and Ω represent the units of centimeters and ohms, respectively; k Cu k represents the proportionality coefficient used in copper electrode measurements. Ag / AgCl This represents the proportionality coefficient used in Ag / AgCl electrode measurements.

[0166] Depend on Figure 7It can be seen that the core resistivity decreases with the increase of water content, which is consistent with the theory. The fitting lines of the two electrodes do not pass through the origin, indicating that there is contact resistance in the measurement. When the water content is 0.83% and 1.01%, the contact resistance of the Cu electrode is about 3kΩ, and the contact resistance of the Ag / AgCl electrode is 652.6Ω and 650Ω respectively; when the water content is 2.00%, 2.94% and 4.36%, the contact resistance of the copper electrode is greater than 500Ω, and the contact resistance of the Ag / AgCl electrode is less than 100Ω at this time, and when the water content of the rock sample is 4.36%, the contact resistance is only 32.42Ω. The results show that for the same rock sample, the contact resistance measured by Ag / AgCl electrode is at least 74% lower than that measured by Cu electrode.

[0167] The measured resistance of the core sample with different water content and length of 2cm is substituted into formula (4) to obtain the resistivity before correction, and the measured resistance and contact resistance are substituted into formula (3) to obtain the standard resistivity. The resistivity error is calculated by formula (5). The actual resistivity and the error of the measured resistivity of the core sample with different water content and length of 2cm are shown in Figure 8 . Among them, the horizontal coordinate Moisture content represents the water content, Resistivity (kΩ·m) represents the resistivity, Corrected Resistivity represents the corrected resistivity, Ag / AgCl represents the error result of example 1, Cu represents the error result of comparative example 1, the actual resistivity is the standard resistivity, and the measured resistivity is the resistivity before correction.

[0168] Figure 8 The resistivity calculation results before and after correcting the contact resistance are compared. The resistivity error of the copper electrode of comparative example 1 is almost more than 30%, and the resistivity error of the Ag / AgCl electrode of example 1 is less than 10%. When the water content of the rock sample is 2.94%, the resistivity error is as low as 2.44%. Overall, the accuracy of the Ag / AgCl flexible electrode of example 1 in measuring the resistivity of the rock is at least 25% higher than that of the Cu electrode.

[0169] The electrical properties of the rock sample are measured by two-phase electrode method and four-phase electrode method using the measuring device of example 1, and the measurement results are shown in Figure 9 . It can be seen from Figure 9 that compared with the theoretically calculated rock impedance data, in the lower frequency range, the accuracy of the rock impedance data measured by the four-phase electrode method is high, and the accuracy of the rock impedance data measured by the two-phase electrode method is low; in the higher frequency range, the accuracy of the rock impedance data measured by the two-phase electrode method is high, and the accuracy of the rock impedance data measured by the four-phase electrode method is low; only by combining the two, accurate rock impedance test data can be obtained.

[0170] In addition, when measuring the rock electrical property, array electrode measurement can be used according to the shape of the rock, that is, a plurality of flexible electrodes are attached to the surface of the rock, the flexible electrodes are respectively connected to the measuring instrument, and the rock electrical property is comprehensively monitored and the electrical property inside the rock is imaged. Figure 10 As shown in the figure.

[0171] In summary, the rock electrical property measuring device of the present application adopts integrated design, that is, the two-phase electrode method and the four-phase electrode method are combined in the same device, for rock sample measurement, the four-phase electrode method can be selected for low-frequency measurement, the two-phase electrode method can be selected for high-frequency measurement, and the two-phase electrode method and the four-phase electrode method are combined for wideband measurement, which greatly widens the frequency band of rock electrical property measurement and improves the measurement accuracy. At the same time, by using specific Ag / AgCl flexible electrodes or graphene modified carbon fiber flexible electrodes, the rock electrical property measurement is more accurate. In addition, the present application can select Ag / AgCl flexible electrodes or graphene modified carbon fiber flexible electrodes according to the actual situation of the rock sample, and when using the four-electrode method, different materials of metal gaskets can be selected according to different electrolytes, that is, the measuring device of the present application has higher applicability.

[0172] The above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A rock electrical property measuring device, characterized in that, It includes a T-shaped fixing rod, wherein the T-shaped fixing rod comprises a horizontal rod and a vertical rod perpendicular to the horizontal rod; A sliding rod, comprising a first sliding rod, a second sliding rod, and a third sliding rod; the second sliding rod is located on the left side of the vertical rod, and the first and third sliding rods are located sequentially on the right side of the vertical rod, the sliding rod sliding along the horizontal rod; A first electrolytic cell and a second electrolytic cell are provided, with the first electrolytic cell located between the second sliding rod and the vertical rod, and the second electrolytic cell located between the first sliding rod and the third sliding rod; The first flexible electrode and the second flexible electrode are respectively connected to the lower ends of the first sliding rod and the vertical rod, and the first flexible electrode and the second flexible electrode are respectively arranged opposite to each other; The first flexible electrode and the second flexible electrode are each independently selected from either Ag / AgCl flexible electrode or graphene-modified carbon fiber flexible electrode. The Ag / AgCl flexible electrode is composed of a substrate layer, a flexible conductive layer, a silver conductive film layer and an Ag / AgCl electrode layer stacked sequentially; the flexible conductive layer is composed of polydimethylsiloxane and silver powder. The base layer is a silver sheet; The graphene-modified carbon fiber flexible electrode is composed of a substrate layer, a flexible conductive layer, a carbon fiber conductive film, and a graphene-modified carbon fiber electrode layer stacked sequentially; the flexible conductive layer is composed of polydimethylsiloxane and silver powder.

2. The rock electrical property measuring device according to claim 1, characterized in that, Both the sliding rod and the vertical rod are hollow metal rods; the upper end of the sliding rod is provided with a through hole, and the sliding rod is connected to the horizontal rod through the through hole.

3. The rock electrical property measuring device according to claim 1, characterized in that, The upper ends of the first sliding rod and the vertical rod are respectively provided with a first terminal and a second terminal. The first terminal is connected to the first flexible electrode through a wire in the first sliding rod; the second terminal is connected to the second flexible electrode through a wire in the vertical rod.

4. The rock electrical property measuring device according to claim 1, characterized in that, The upper ends of the second sliding rod and the third sliding rod are respectively provided with a third terminal and a fourth terminal. The third terminal is connected to the first electrolytic cell through a wire in the second sliding rod; the fourth terminal is connected to the second electrolytic cell through a wire in the third sliding rod.

5. The rock electrical property measuring device according to claim 1, characterized in that, The Ag / AgCl electrode layer has a porous structure, and the composition of the Ag / AgCl electrode layer includes Ag particles and AgCl particles.

6. A method for measuring the electrical properties of rocks, characterized in that, The rock electrical property measuring device according to any one of claims 1-5 is used to perform two-phase electrode measurement and / or four-phase electrode measurement. The two-phase electrode measurement method includes the following steps: The two ends of the rock sample are attached to the first flexible electrode and the second flexible electrode, respectively. Then, the second terminal is connected to the voltage terminal of the measuring instrument, and the first terminal is connected to the current terminal of the measuring instrument for measurement. The four-phase electrode measurement method includes the following steps: The two ends of the rock sample are attached to the first flexible electrode and the second flexible electrode, respectively. Then, the third and fourth terminals are connected to the voltage terminals of the measuring instrument, and the first and second terminals are connected to the current terminals of the measuring instrument for measurement.

7. The application of the rock electrical property measuring device according to any one of claims 1-5 in the field of rock measurement.

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