Drilling fluid hydration inhibition evaluation device and test method

Abstract

The invention belongs to the technical field of oil drilling, and particularly relates to a drilling fluid hydration inhibition evaluation device and a testing method.The drilling fluid hydration inhibition evaluation device comprises a core holder used for clamping a core; the four-electrode structure is used for applying current and voltage to the rock core; the pressurizing structure is used for applying pressure to the rock core; the heating structure is arranged between the rock core holder and the rock core, and the heating structure is used for heating the rock core. The device can simulate the high-temperature and high-pressure environment of a real shale formation, and detect the microcrack propagation condition of the shale when the shale is in contact with the drilling fluid in real time, so as to evaluate the hydration inhibition effect of the drilling fluid.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum drilling, and in particular relates to a drilling fluid hydration inhibition evaluation device and a testing method. Background Art

[0002] There are many natural microcracks in shale formations, and their interaction with water-based drilling fluid is an important cause of wellbore instability. When drilling into shale formations with water-based drilling fluid, the shale will undergo strong hydration after absorbing water, which promotes the generation of secondary cracks. The cracks intersect and connect to form a more complex network structure, which reduces the strength of the shale and ultimately causes wellbore instability. Therefore, adding hydration inhibitors to water-based drilling fluids can weaken the expansion of microcracks, effectively slow down the hydration effect of shale, and thus improve wellbore stability.

[0003] At present, there are many methods to evaluate the hydration inhibition of drilling fluids, such as shale expansion test, rolling recovery rate test, bentonite immersion test, etc., which are the most intuitive experiments to evaluate the hydration inhibition effect of drilling fluids, but they are unable to judge and analyze the expansion of microcracks inside shale. Yan Xinxin et al. used a laser particle size analyzer to measure the particle size distribution of clay in "Study on the Method of Evaluating Polyol Inhibitors by Particle Size Distribution" to evaluate the effect of drilling fluid hydration inhibition, but the experimental results were greatly affected by the stirring time and stirring rate, and the instrument was expensive and could not be popularized. Luo Xingshu et al. used the CST determination method to evaluate the hydration inhibition of drilling fluids in "Experimental Study on the Specific Surface Area Determination Method of Shale". This method is a simple, time-saving and highly accurate method, but the experimental results have poor repeatability. Liu Zhendong et al. used the acoustic wave velocity measurement method to evaluate the inhibitory effect of shale fracture expansion in the "Study on the Evaluation Method of Nano-Plugging Effect". This method uses the difference in the transmission rate of acoustic waves in the core after the action of nanomaterials to compare and analyze the changes in the strength of the core blocks, but the data repetition rate is low and the reliability is poor, so it can only be used to qualitatively analyze the shale inhibition effect. The patent with publication number CN109342187A obtains the changes in mechanical strength parameters through triaxial tests to evaluate the inhibitory performance of shale drilling fluid. The patent with publication number CN104569149A measures the relative rock strength of core slices through an acoustic wave velocimeter to evaluate the inhibitory property of shale drilling fluid. However, neither of the above two methods can realize real-time detection of the expansion of microcracks in shale when it comes into contact with drilling fluid.

[0004] The shortcomings of the existing technical solutions are summarized as follows: ① The instruments required for the evaluation method are expensive and heavy, and cannot be extended to laboratory and field applications; ② The evaluation method has limitations, the test results are greatly affected by the rock samples, the data accuracy is low, and the repeatability is poor; ③ The current evaluation methods rarely consider the expansion of microcracks in shale when it comes into contact with drilling fluid in a high temperature and high pressure environment. Summary of the invention

[0005] The purpose of the present invention is to provide a drilling fluid hydration inhibition evaluation device and a testing method to solve the above-mentioned problems, so as to simulate the high temperature and high pressure environment of real shale formations, and detect the expansion of microcracks in shale when it contacts with drilling fluid in real time, so as to evaluate the hydration inhibition effect of drilling fluid.

[0006] To achieve the above object, the present invention provides the following solution: a drilling fluid hydration inhibition evaluation device, comprising

[0007] A core holder, wherein the core holder is used to hold the core;

[0008] a four-electrode structure, the four-electrode structure being used to apply current and voltage to the core;

[0009] A pressurizing structure, the pressurizing structure is used to apply pressure to the core;

[0010] A heating structure is disposed between the core holder and the core, and is used to heat the core.

[0011] Preferably, the four-electrode structure includes a power supply electrode A, a power supply electrode B, a measuring electrode M, and a measuring electrode N. The power supply electrode A and the power supply electrode B are symmetrically arranged at both ends of the core and in contact with the core. The measuring electrode M and the measuring electrode N are arranged in the middle of the core and are symmetrical about the vertical center plane of the core. The measuring electrode M and the measuring electrode N are in contact with the core. The distance between the power supply electrode A and the measuring electrode M, and the distance between the power supply electrode B and the measuring electrode N are equal. The power supply electrode A, the power supply electrode B, and the core are electrically connected to a power source.

[0012] Preferably, the power supply electrode A and the power supply electrode B are electrically connected to the switch X of the power supply, the switch Y of the power supply is electrically connected to the core, an ammeter is provided between the power supply electrode A and the switch X of the power supply, the measuring electrode M and the measuring electrode N are electrically connected to a voltmeter, and the voltmeter is electrically connected to a data collector.

[0013] Preferably, a second resistor is provided between the power supply electrode A and the ammeter, and a first resistor is provided between the measuring electrode M and the voltmeter.

[0014] Preferably, the pressurizing structure includes a drilling fluid adding tank and a simulated formation water adding tank, the drilling fluid adding tank is connected to the upstream of the core clamp, the simulated formation water adding tank is connected to the downstream of the core clamp, and a confining pressure pump is connected to the middle of the core clamp.

[0015] Preferably, an upstream high-pressure pump is arranged between the drilling fluid adding tank and the upstream of the core clamp, a downstream high-pressure pump is arranged between the simulated formation water adding tank and the downstream of the core clamp, and pressure sensors are arranged between the upstream high-pressure pump and the upstream of the core clamp, and between the downstream high-pressure pump and the downstream of the core clamp.

[0016] Preferably, the core clamp includes a shell, the side wall of the shell is covered with an insulation layer, the core is arranged inside the shell, the heating structure is arranged between the shell and the core, end covers are respectively provided at both ends of the shell, and clamping members are provided on the end covers, one of the clamping members is connected to the drilling fluid filling tank through an upstream inlet, and the other clamping member is connected to the simulated formation water filling tank through a downstream inlet.

[0017] Preferably, an upstream control valve is provided between the upstream inlet and the drilling fluid adding tank, and a downstream control valve is provided between the downstream inlet and the simulated formation water adding tank.

[0018] Preferably, the heating structure comprises a heating layer, wherein the heating layer is arranged between the shell and the core, an electric heating tube is arranged inside the heating layer, the electric heating tube is electrically connected to a thermocouple, and the thermocouple is electrically connected to a temperature controller.

[0019] A method for testing a drilling fluid hydration inhibition evaluation device comprises the following steps:

[0020] S1. Make a core, measure the cross-sectional area S of the core, install the core in a core holder, and connect the four-electrode structure to the core;

[0021] S2, heating the core by means of a heating structure;

[0022] S3, pressurizing the core through a pressurizing structure;

[0023] S4. Power the core through the four-electrode structure and measure the current I and potential difference ΔU of the core. MN , the core resistivity ρ is calculated by the following formula;

[0024]

[0025] Where: ρ is the core resistivity;

[0026] ΔU MN is the potential difference between the measuring electrode M and the measuring electrode N;

[0027] I is the current passing through the core;

[0028] S is the cross-sectional area through the core;

[0029] L is the length between the measuring electrode M and the measuring electrode N.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] 1. The present invention is simple to operate, easy to carry, and can be used for laboratory and field measurements. The method for measuring shale resistivity is the four-electrode method, in which two electrodes are placed at both ends of the rock sample and current excitation is applied, and then the voltage between two points between the two electrodes is measured. The resistivity can be calculated based on the relationship between current and voltage, and the resistivity change of shale before and after being treated with different drilling fluids is used to evaluate its hydration inhibition.

[0032] 2. The present invention has the characteristics of high precision and repeatability. The four-electrode method has low requirements for rock samples, is not affected by the type of rock samples, and has a reasonable structural design, which can effectively separate the current injection and voltage measurement processes, thereby reducing the influence of contact resistance and polarization effect on the measurement results, extending the service life of the equipment, and is suitable for long-term field measurements, ensuring high measurement accuracy and repeatability.

[0033] 3. The present invention can simulate the high temperature and high pressure environment of real shale formations. The heating structure and the pressurizing structure simulate the high temperature and high pressure environment of shale formations, and more accurately evaluate the shale hydration inhibition effect of the drilling fluid in the real formation environment.

[0034] 4. The present invention can detect the expansion of microcracks in shale when it contacts drilling fluid in real time. Drilling fluid and simulated formation water are injected into the upstream and downstream through a pressurized structure, and a stable pressure difference is set, so that the drilling fluid can stably penetrate into the core, and the resistivity of the shale is measured in real time, thereby achieving the purpose of real-time detection of the expansion of microcracks in shale when it contacts drilling fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0036] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of the core holder of the present invention.

[0038] Among them, 1. core holder; 2. first resistor; 3. second resistor; 4. ammeter; 5. voltmeter; 6. data acquisition device; 7. temperature controller; 8. power supply; 9. drilling fluid adding tank; 10. simulated formation water adding tank; 11. pressure sensor; 12. upstream high-pressure pump; 13. downstream high-pressure pump; 14. confining pressure pump; 15. upstream inlet; 16. downstream inlet; 17. power supply electrode A; 18. power supply electrode B; 19. measuring electrode M; 20. measuring electrode N; 21. core; 22. heating layer; 23. electric heating pipe; 24. thermocouple; 25. confining pressure; 26. end cover; 27. clamp; 28. upstream control valve; 29. ​​downstream control valve; 30. insulation layer; 31. shell. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Reference Figure 1 to Figure 2 As shown, the present invention provides a drilling fluid hydration inhibition evaluation device, comprising a core clamp 1, the core clamp 1 is used to clamp a core 21;

[0042] A four-electrode structure, the four-electrode structure is used to apply current and voltage to the core 21;

[0043] A pressurizing structure, which is used to apply pressure to the core 21;

[0044] A heating structure is provided between the core holder 1 and the core 21 , and is used to heat the core 21 .

[0045] A further optimized solution is provided, in which the four-electrode structure includes a power supply electrode A17, a power supply electrode B18, a measuring electrode M19, and a measuring electrode N20. The power supply electrode A17 and the power supply electrode B18 are symmetrically arranged at both ends of the core 21 and in contact with the core 21. The measuring electrode M19 and the measuring electrode N20 are arranged in the middle of the core 21 and are symmetrical about the vertical center plane of the core 21. The measuring electrode M19 and the measuring electrode N20 are in contact with the core 21. The distance between the power supply electrode A17 and the measuring electrode M19, and the distance between the power supply electrode B18 and the measuring electrode N20 are equal. The power supply electrode A17, the power supply electrode B18, and the core 21 are electrically connected to a power supply 8.

[0046] The power supply electrodes A17 and B18 should maintain good contact with the core 21, and the power supply electrodes A17 and B18 should maintain a uniform and symmetrical spacing with the measuring electrodes M19 and N20 to ensure the accuracy of the measurement.

[0047] Further optimizing the scheme, the power supply electrode A17 and the power supply electrode B18 are electrically connected to the switch X of the power supply 8, the switch Y of the power supply 8 is electrically connected to the core 21, an ammeter 4 is arranged between the power supply electrode A17 and the switch X of the power supply 8, the measuring electrode M19 and the measuring electrode N20 are electrically connected to the voltmeter 5, and the voltmeter 5 is electrically connected to the data collector 6.

[0048] According to a further optimized solution, a second resistor 3 is provided between the power supply electrode A17 and the ammeter 4 , and a first resistor 2 is provided between the measuring electrode M19 and the voltmeter 5 .

[0049] To further optimize the solution, the pressurizing structure includes a drilling fluid adding tank 9 and a simulated formation water adding tank 10. The drilling fluid adding tank 9 is connected to the upstream of the core holder 1, the simulated formation water adding tank 10 is connected to the downstream of the core holder 1, and a confining pressure pump 14 is connected to the middle of the core holder 1.

[0050] To further optimize the solution, an upstream high-pressure pump 12 is arranged between the drilling fluid adding tank 9 and the upstream of the core clamp 1, a downstream high-pressure pump 13 is arranged between the simulated formation water adding tank 10 and the downstream of the core clamp 1, and pressure sensors 11 are arranged between the upstream high-pressure pump 12 and the upstream of the core clamp 1, and between the downstream high-pressure pump 13 and the downstream of the core clamp 1.

[0051] A further optimized solution is that the core clamp 1 includes a shell 31, the side wall of the shell 31 is coated with an insulation layer 30, the core 21 is arranged inside the shell 31, the heating structure is arranged between the shell 31 and the core 21, and end covers 26 are respectively provided at both ends of the shell 31. A clamping member 27 is provided on the end cover 26, one clamping member 27 is connected to the drilling fluid filling tank 9 through the upstream inlet 15, and the other clamping member 27 is connected to the simulated formation water filling tank 10 through the downstream inlet 16.

[0052] According to a further optimized solution, an upstream control valve 28 is provided between the upstream inlet 15 and the drilling fluid adding tank 9 , and a downstream control valve 29 is provided between the downstream inlet 16 and the simulated formation water adding tank 10 .

[0053] According to a further optimization scheme, the heating structure includes a heating layer 22 , which is arranged between the shell 31 and the core 21 , and an electric heating tube 23 is arranged inside the heating layer 22 , the electric heating tube 23 is electrically connected to a thermocouple 24 , and the thermocouple 24 is electrically connected to a temperature controller 7 .

[0054] The heating layer 22 can be made of copper material that is resistant to high temperature and high pressure and has good heat transfer performance, and the insulation layer 30 can be made of polyurethane foam insulation material that is resistant to high temperature and has good heat preservation performance.

[0055] The electric heating tube 23 heats the core holder 1 barrel through the heating layer 22, and the temperature controller 7 sets and controls the temperature through the thermocouple 24. When the preset temperature is reached, the temperature controller 7 automatically cuts off the power supply 8 switch Y and maintains a constant temperature. The confining pressure pump 14 applies pressure to the core holder 1 barrel, and the upstream high-pressure pump 12 and the downstream high-pressure pump 13 are used to set a stable pressure difference between the upstream and downstream of the core holder 1, so as to continuously add hydraulic pressure to the core holder 1 barrel to achieve the purpose of pressurization.

[0056] The first resistor 2 and the second resistor 3 are used to protect the voltmeter 5 and the ammeter 4 respectively to prevent the instruments from being damaged by excessive current; the voltmeter 5 is connected in parallel to the measuring electrode M19 and the measuring electrode N20 to measure the potential difference, and the ammeter 4 is connected in series in the circuit to determine the current intensity.

[0057] A method for testing a drilling fluid hydration inhibition evaluation device comprises the following steps:

[0058] S1, making a core 21, measuring the cross-sectional area S of the core 21, installing the core 21 in the core holder 1, and connecting the four-electrode structure to the core 21;

[0059] The shale is ground into a cylindrical core 21 with a regular shape, and the cross-sectional area of ​​the core 21 is measured to be S. The processed core 21 is placed in the core holder 1, and the power supply electrodes A17 and B18 are connected to the two ends of the core 21, and the ring-shaped measuring electrodes M19 and N20 are connected to the middle part of the core 21. The length L between the measuring electrodes M19 and N20 is set to 1 / 3 of the length of the core 21, and the core 21 is connected to the circuit;

[0060] S2, heating the core 21 by means of a heating structure;

[0061] Turn on the switch Y of the power supply 8, use the electric heating tube 23 to heat the core holder 1, use the thermocouple 24 to measure the temperature inside the core holder 1, and set the preset temperature through the temperature controller 7 and control it;

[0062] S3, pressurizing the core 21 through the pressurizing structure;

[0063] Confining pressure 25 is injected into the barrel by confining pressure pump 14, drilling fluid is injected from upstream inlet 15, and the pressure of upstream inlet 15 is adjusted by upstream high-pressure pump 12. Similarly, simulated formation water is injected from downstream inlet 16, and the pressure of downstream inlet 16 is adjusted by downstream high-pressure pump 13 to form a stable pressure difference. Drilling fluid adding tank 9 and simulated formation water adding tank 10 continuously inject stable drilling fluid and simulated formation water into core holder 1;

[0064] S4. Power the core 21 through the four-electrode structure and measure the current I and potential difference ΔU of the core 21. MN , the resistivity ρ of core 21 is calculated by the following formula;

[0065]

[0066] Where: ρ is the core 21 resistivity;

[0067] ΔU MN is the potential difference between the measuring electrode M19 and the measuring electrode N20;

[0068] I is the current passing through the core 21;

[0069] S is the cross-sectional area through the core 21;

[0070] L is the length between the measuring electrode M19 and the measuring electrode N20.

[0071] Turn on the power supply 8 switch X, power the core 21 through the electrode power supply electrode A17 and the power supply electrode B18, determine the current intensity I by the ammeter 4, connect the measuring electrode M19 and the measuring electrode N20 by the voltmeter 5, measure the value of the potential difference ΔUMN between the measuring electrode M19 and the measuring electrode N20, connect the voltmeter 5 to the data acquisition device 6, and detect the expansion of the hydration cracks in the core 21 in real time through the dynamic change of the resistivity data.

[0072] By replacing the drilling fluid in the drilling fluid adding tank 9, the resistivity of the core 21 when different drilling fluids act on it is measured by the data acquisition device 6, and the hydration inhibition of the drilling fluid is evaluated according to the change of the resistivity.

[0073] The specific operation steps of the present invention are as follows:

[0074] ① First, prepare the test sample: grind the shale into a regular cylindrical shape, specify its diameter and length to determine the cross-sectional area S, and put the processed rock sample into the core holder 1;

[0075] ②According to Figure 2Install the core holder 1: connect power supply electrodes A17 and B18 at both ends of the core 21 in the barrel, connect annular measuring electrodes M19 and N20 to the middle part of the core 21, set the spacing between the measuring electrodes M19 and N20 to 1 / 3 of the length of the core 21, fix the electric heating tube 23 and the thermocouple 24 in the barrel, the heating layer 22 can be made of copper material that is resistant to high temperature and high pressure and has good heat transfer performance, and the insulation layer 30 can be made of polyurethane foam insulation material that is resistant to high temperature and has good heat preservation.

[0076] ③According to Figure 1 Install the circuit: the measuring electrode M19 and the measuring electrode N20 are connected in parallel with the first resistor 2 and the voltmeter 5 respectively, the voltmeter 5 is connected to the data acquisition device 6, the power supply electrode A17 and the power supply electrode B18 are connected in series with the second resistor 3, the ammeter 4 and the power supply 8 respectively, and the core 21 is connected to the circuit;

[0077] ④According to Figure 1 Install the heating structure and the pressurizing structure: the electric heating pipe 23 is heated by the heating layer 22 in the core holder 1 and connected to the thermocouple 24. The thermocouple 24 measures the temperature in the core holder 1 and is connected to the temperature controller 7 to control the temperature, forming a heating system; the confining pressure pump 14 injects confining pressure 25 into the core holder 1, the drilling fluid adding tank 9, the upstream high-pressure pump 12 and the pressure sensor 11 are connected upstream of the core holder 1, the simulated formation water adding tank 10, the downstream high-pressure pump 13 and another pressure sensor 11 are connected downstream of the core holder 1, and hydraulic pressure is injected into the core holder 1 to form a pressurizing structure;

[0078] ⑤ After the experimental device is connected, heat the core holder 1 to reach the specified temperature. Turn on the switch Y of the power supply 8, use the electric heating tube 23 to heat the core holder 1, use the thermocouple 24 to measure the temperature inside the core holder 1, and set the specified temperature through the temperature controller 7;

[0079] ⑥ Inject the specified confining pressure 25 into the core holder 1 through the confining pressure pump 14, adjust the pressure of the upstream high-pressure pump 12, open the upstream control valve 28 to inject drilling fluid A, and similarly, open the downstream control valve 29 to inject simulated formation water, adjust the downstream high-pressure pump 13, increase the pressure of the upstream high-pressure pump 12, and make the pressure of the upstream high-pressure pump 12 higher than that of the downstream high-pressure pump 13, so as to achieve the stability of the upstream and downstream pressure difference and the stable infiltration of the drilling fluid during the experimental test;

[0080] ⑦ After the drilling fluid and simulated formation water are injected into the core holder 1, they are in full contact with the core 21, and the pressure difference is used to make the drilling fluid fully interact with the core 21 in the barrel;

[0081] ⑧ After the action is over, turn on the switch X of the power supply 8, and power the core 21 through the power supply electrode A17 and the power supply electrode B18. The ammeter 4 determines that the current intensity reaches the specified value. The voltmeter 5 is connected to the data acquisition device 6 to detect the resistivity of the core 21 and extract data, and detect the expansion of the hydration cracks in the core 21 under the action of the drilling fluid in real time;

[0082] ⑨ Adjust the type of drilling fluid to be injected, inject drilling fluid B from the upstream of core holder 1, and repeat steps ⑥-⑧;

[0083] After the drilling fluid inhibition evaluation experiment is completed, first turn off the switch X and switch Y of the power supply 8 to stop the power supply, then drain the liquid in the core holder 1, turn off the upstream high-pressure pump 12 and the confining pressure pump 14, adjust the downstream high-pressure pump 13, unload the pressure and temperature in the core holder 1, and after the temperature drops to room temperature, take out the core 21 from the core holder 1 and store it;

[0084] The resistivity data of the core 21 in the above-mentioned experiment is extracted and sorted by the data acquisition device 6, so as to determine the expansion of hydration fractures in the core 21 under different drilling fluid conditions and evaluate the hydration inhibition of the drilling fluid.

[0085] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0086] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope of the present invention.

Claims

1. A drilling fluid hydration inhibition evaluation device, characterized in that: include A core holder (1), the core holder (1) being used to hold a core (21); A four-electrode structure, the four-electrode structure is used to apply current and voltage to the core (21); A pressurizing structure, the pressurizing structure is used to apply pressure to the core (21); A heating structure is provided between the core holder (1) and the core (21), and is used to heat the core (21).

2. A drilling fluid hydration inhibition evaluation device according to claim 1, characterized in that: The four-electrode structure comprises a power supply electrode A (17), a power supply electrode B (18), a measuring electrode M (19), and a measuring electrode N (20). The power supply electrode A (17) and the power supply electrode B (18) are symmetrically arranged at two ends of the core (21) and in contact with the core (21). The measuring electrode M (19) and the measuring electrode N (20) are arranged in the middle of the core (21) and are symmetrical about the vertical center plane of the core (21). The measuring electrode M (19) and the measuring electrode N (20) are in contact with the core (21). The distance between the power supply electrode A (17) and the measuring electrode M (19) and the distance between the power supply electrode B (18) and the measuring electrode N (20) are equal. The power supply electrode A (17), the power supply electrode B (18), and the core (21) are electrically connected to a power source (8).

3. A drilling fluid hydration inhibition evaluation device according to claim 2, characterized in that: The power supply electrode A (17) and the power supply electrode B (18) are electrically connected to the switch X of the power supply (8), the switch Y of the power supply (8) is electrically connected to the core (21), an ammeter (4) is arranged between the power supply electrode A (17) and the switch X of the power supply (8), the measuring electrode M (19) and the measuring electrode N (20) are electrically connected to a voltmeter (5), and the voltmeter (5) is electrically connected to a data acquisition device (6).

4. A drilling fluid hydration inhibition evaluation device according to claim 3, characterized in that: A second resistor (3) is provided between the power supply electrode A (17) and the ammeter (4), and a first resistor (2) is provided between the measuring electrode M (19) and the voltmeter (5).

5. The drilling fluid hydration inhibition evaluation device according to claim 1, characterized in that: The pressurizing structure comprises a drilling fluid charging tank (9) and a simulated formation water charging tank (10); the drilling fluid charging tank (9) is connected to the upstream of the core holder (1); the simulated formation water charging tank (10) is connected to the downstream of the core holder (1); and a confining pressure pump (14) is connected to the middle of the core holder (1).

6. A drilling fluid hydration inhibition evaluation device according to claim 5, characterized in that: An upstream high-pressure pump (12) is arranged between the drilling fluid filling tank (9) and the upstream of the core clamp (1), a downstream high-pressure pump (13) is arranged between the simulated formation water filling tank (10) and the downstream of the core clamp (1), and pressure sensors (11) are arranged between the upstream high-pressure pump (12) and the upstream of the core clamp (1), and between the downstream high-pressure pump (13) and the downstream of the core clamp (1).

7. A drilling fluid hydration inhibition evaluation device according to claim 5, characterized in that: The core holder (1) comprises a shell (31), the side wall of which is coated with a heat-insulating layer (30), the core (21) is arranged inside the shell (31), the heating structure is arranged between the shell (31) and the core (21), and end covers (26) are respectively arranged at both ends of the shell (31), and clamping members (27) are arranged on the end covers (26), one of the clamping members (27) is connected to the drilling fluid filling tank (9) through an upstream inlet (15), and the other of the clamping members (27) is connected to the simulated formation water filling tank (10) through a downstream inlet (16).

8. A drilling fluid hydration inhibition evaluation device according to claim 7, characterized in that: An upstream control valve (28) is provided between the upstream inlet (15) and the drilling fluid filling tank (9), and a downstream control valve (29) is provided between the downstream inlet (16) and the simulated formation water filling tank (10).

9. The drilling fluid hydration inhibition evaluation device according to claim 7, characterized in that: The heating structure comprises a heating layer (22), wherein the heating layer (22) is arranged between the shell (31) and the core (21), an electric heating pipe (23) is arranged inside the heating layer (22), the electric heating pipe (23) is electrically connected to a thermocouple (24), and the thermocouple (24) is electrically connected to a temperature controller (7).

10. A method for testing the drilling fluid hydration inhibition evaluation device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, making a core (21), measuring the cross-sectional area S of the core (21), installing the core (21) in a core holder (1), and connecting a four-electrode structure to the core (21); S2, heating the core (21) by means of a heating structure; S3, pressurizing the core (21) by a pressurizing structure; S4. The core (21) is electrified through the four-electrode structure, and the current I and the potential difference ΔU of the core (21) are measured. MN , the core resistivity ρ (21) is calculated by the following formula; Where: ρ is the resistivity of the core (21); ΔU MN is the potential difference between the measuring electrode M (19) and the measuring electrode N (20); I is the current passing through the core (21); S is the cross-sectional area through the core (21); L is the length between the measuring electrode M (19) and the measuring electrode N (20).

Images