Spontaneous imbibition experiment device for imbibition agent

Abstract

The utility model discloses an imbibition agent spontaneous imbibition experiment device which comprises a constant-temperature box, an imbibition metering bottle is arranged in the constant-temperature box, the imbibition metering bottle is in an inverted funnel shape, a sealing base is arranged at a lower port of the imbibition metering bottle, a rock core holder is fixed on the sealing base, a rock core is clamped in the rock core holder, the circumference of the rock core is sealed, and two ends of the rock core are exposed. An imbibition agent is injected into the imbibition metering bottle, a metering vertical pipe extending upwards is arranged in the center of an upper port of the imbibition metering bottle, and volume scales of the imbibition metering bottle are arranged on the outer wall of the metering vertical pipe. An imbibition agent container bottle is further arranged in the constant-temperature box, a bottom inlet of the imbibition agent container bottle is connected with an outlet of the constant-flux pump, a top outlet of the imbibition agent container bottle is connected with an imbibition agent injection pipe, and an outlet of the imbibition agent injection pipe is inserted into an upper port of the metering vertical pipe and is higher than the top scale mark. The device overcomes the influence of gravity, buoyancy and the specific surface area of the rock core on the imbibition effect in the experiment process, and can accurately measure the imbibition rate.

Description

Technical Field

[0001] The utility model relates to an oil field experimental device, in particular to an imbibition agent spontaneous imbibition experimental device, belonging to the technical field of oil and gas development experimental equipment. Background Art

[0002] With the increase in energy demand and the development of oil and gas development technology, low-permeability and ultra-low-permeability reservoirs have become an important part of my country's oil and gas resources. This type of reservoir generally has the characteristics of low porosity, low permeability, low pressure coefficient, strong heterogeneity, etc. The recovery rate of elastic development is low, and it is difficult to form effective displacement of water injection development, resulting in poor development effect. Imbibition replacement is the process in which the wet phase spontaneously enters the capillary by capillary force to replace the non-wet phase. It is a common phenomenon in the development of low-permeability and ultra-low-permeability reservoirs. As one of the important means of efficient development of low-permeability and ultra-low-permeability reservoirs, imbibition oil production can reuse the heterogeneity of the reservoir, introduce the injected fluid into the reservoir, form a high-pressure zone, and undergo imbibition replacement with the surrounding high-saturation matrix during the well soaking process. It has become the main development method for this type of reservoir.

[0003] According to different external environments, imbibition can be divided into static spontaneous imbibition occurring in a static liquid environment and dynamic imbibition under a certain speed flow state of external liquid. For water-wet formations, crude oil is a non-wetting phase and formation water is a wetting phase. In the absence of external pressure, formation water can effectively displace part of the crude oil in the rock matrix mainly by capillary force, thus forming a spontaneous imbibition oil displacement process. The spontaneous imbibition experiment simulates the spontaneous imbibition oil displacement process when the external liquid of the matrix system is in a static state. Capillary force is the main driving force. The imbibition medium is sucked into the small pores under the action of capillary force and drives the crude oil into the large pores. The crude oil is finally discharged through the large pores.

[0004] The existing patents and documents involve the following devices and methods for spontaneous imbibition experiments of imbibition agents:

[0005] The Chinese invention patent with the announcement number CN103510933B discloses a quantitative evaluation method for the imbibition oil recovery effect of an imbibition agent. Based on the volumetric method, the oil-saturated core is placed in a self-imbibition cylinder, an appropriate amount of imbibition agent solution is added, and the volume of imbibition oil removed is read through the scale at the top to calculate the imbibition recovery rate of the imbibition agent. This quantitative evaluation method cannot control the contact area between the core and the imbibition agent solution, which has a great impact on the final imbibition recovery result.

[0006] The Chinese invention patent with the announcement number CN111855522B discloses a core holder, a high-temperature and high-pressure core imbibition agent spontaneous imbibition experimental device and method, wherein the target core is placed in the core holder, and the upper and lower ends of the holder are provided with covers, and the spiral structure is used inside to direct the flow of the seepage liquid. In the device and method, the upper and lower end faces of the core are in vertical contact with the imbibition agent, which is easily affected by gravity and buoyancy, and the solid-liquid contact surface cannot be controlled, which has a great impact on the experimental results.

[0007] The Chinese invention patent application with publication number CN111323834A discloses an imbibition device for online monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology. The core is placed in a non-magnetic imbibition chamber and immersed in an imbibition liquid. This method places the core vertically in the imbibition liquid. The imbibition effect of the upper and lower end faces is affected by gravity to a certain extent, and the contact area between the core and the imbibition agent has a greater influence on the imbibition recovery rate. The final result is affected by the specific surface area of ​​the core.

[0008] In the article "Study on Static Imbibition Law of Tight Reservoir Cores" in the Journal of Yangtze University (Natural Science Edition) 2023 Issue 03, Ma Chao et al. used a tight oil chamber imbibition experimental device based on the mass method, placed the aged core in the core chamber and added imbibition fluid, completely immersed the core, and used a computer to record the sampling time, core mass, temperature and pressure, and calculated the imbibition recovery rate through core quality analysis. In this method, the core is suspended vertically in the imbibition fluid, and the imbibition effect of the upper and lower end faces is affected by gravity to a certain extent; the contact surface between the core and the imbibition fluid is the entire core surface, and the calculation of the imbibition recovery rate is affected by the core length and specific surface area.

[0009] Summarizing the existing research methods, there are mainly the following problems:

[0010] 1. For low-permeability and ultra-low-permeability reservoirs, capillary force is the main driving force of spontaneous imbibition in the original state. The direction of imbibition will also determine the effect of gravity. For vertical cores, the effect of gravity on improving recovery is much greater than that of horizontal cores. Therefore, it is particularly important to control the placement of the core in the experiment and overcome the influence of gravity for accurate research on imbibition recovery;

[0011] 2. Most of the experiments are based on weighing method, volume method and nuclear magnetic resonance method. The experimental method is to immerse the core in the imbibition agent in its entirety or in part. The contact surface between the core and the imbibition agent is the entirety or in part, and the imbibition efficiency is greatly affected by the contact area between the core and the imbibition agent. Utility Model Content

[0012] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0013] The utility model provides a spontaneous imbibition experimental device of an imbibition agent, which mainly solves the following technical problems existing in the prior art:

[0014] 1. The direction of imbibition determines the magnitude of gravity’s influence. For vertical cores, gravity’s effect on improving oil recovery is much greater than that for horizontal cores. Existing experimental devices and methods generally ignore the influence of gravity.

[0015] 2. Most of the experiments are based on weighing method, volume method and nuclear magnetic resonance method. The experimental method is to immerse the entire core into the infiltrant. The contact surface between the core and the infiltrant is the entire core or part of it. The infiltration efficiency is greatly affected by the contact area between the core and the infiltrant.

[0016] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0017] In order to solve the above technical problems, the utility model provides a spontaneous imbibition experimental device of an imbibition agent, comprising a constant temperature box, in which an imbibition measuring bottle is provided, the imbibition measuring bottle is in the shape of an inverted funnel and a sealing base is provided at the lower end, a core holder is fixed on the sealing base, a core is clamped in the core holder, the circumference of the core is sealed and both ends are exposed, the imbibition measuring bottle is filled with imbibition agent, a measuring vertical tube extending upward is provided at the center of the upper end of the imbibition measuring bottle, and the outer wall of the measuring vertical tube is provided with a volume scale of the imbibition measuring bottle.

[0018] As an improvement of the utility model, the thermostatic box is also provided with an imbibition agent container bottle, the bottom inlet of the imbibition agent container bottle is connected to the outlet of the horizontal flow pump, the top outlet of the imbibition agent container bottle is connected to the imbibition agent injection tube, and the outlet of the imbibition agent injection tube is inserted into the upper port of the metering vertical tube and is higher than the top scale line.

[0019] As a further improvement of the utility model, the core holder is cylindrical and its axis is parallel to the sealing base.

[0020] As a further improvement of the utility model, the lower port of the absorption metering bottle is provided with an internal thread, and the outer periphery of the sealing base is provided with an external thread which is screwed into the internal thread of the lower port of the absorption metering bottle.

[0021] As a further improvement of the utility model, the outer periphery of the core is wrapped with a sealing rubber sleeve, the two ends of the sealing rubber sleeve extend beyond the two ends of the core, and the sealing rubber sleeve is placed in the core holder with clearance fit.

[0022] As a further improvement of the utility model, the core clamp is fixed on the upper end surface of the sealing base, and a downwardly extending annular pressure injection port is provided at the bottom of the middle section of the core clamp, the inner port of the annular pressure injection port is communicated with the outer peripheral annular gap of the sealing rubber sleeve, and the lower end of the annular pressure injection port passes through the central hole of the sealing base and is sealed with each other.

[0023] As a further improvement of the utility model, an annular groove is provided on the outer wall of the middle section of the annular pressure injection port, and an O-ring is embedded in the annular groove to achieve sealing with the central hole of the sealing base.

[0024] As a further improvement of the utility model, the outlet of the ring pressure monitoring pump is connected to the ring pressure injection port through a ring pressure pipeline and a ring pressure valve.

[0025] As a further improvement of the utility model, sealing inner sleeves are respectively inserted at both ends of the core clamp, and the circumferential wall of the sealing inner sleeve rests against the sealing rubber sleeve to press the two ends of the sealing rubber sleeve against the inner walls of the two ports of the core clamp, and the inner port of the sealing inner sleeve is pressed against the outer end face of the core.

[0026] As a further improvement of the utility model, the outer ports of the sealing inner sleeve are respectively provided with inner sleeve outer flanges, and the steps of the inner sleeve outer flanges respectively abut against the outer ports of the core holder.

[0027] As a further improvement of the utility model, the inner end of the sealing inner sleeve is provided with a circular arc chamfer.

[0028] As a further improvement of the utility model, the outer peripheries of both ends of the core clamp are respectively provided with external threads of the clamp, a pressure cap is screwed on the external threads of the clamp, an inner step in the middle of the pressure cap is pressed on the outer port of the core clamp, a pressure cap center hole which passes through the inner hole of the sealing inner sleeve is provided at the center of the outer end face of the pressure cap, and the outer inner step of the pressure cap is pressed on the outer side of the outer flange of the inner sleeve.

[0029] As a further improvement of the utility model, an inner sleeve sealing ring is embedded in the outer periphery of the outer flange of the inner sleeve to achieve sealing with the inner peripheral wall of the middle inner step of the gland.

[0030] As a further improvement of the utility model, the outer end surface or the outer peripheral wall of the gland is symmetrically provided with gland countersunk holes for disassembly and assembly.

[0031] As a further improvement of the utility model, both ends of the core holder are fixed to the upper end surface of the sealing base through clamps respectively.

[0032] Compared with the prior art, the utility model has achieved the following beneficial effects: the experimental device proposed by the present invention can effectively control the contact area between the core and the imbibition agent, and at the same time limit the contact surface to the vertical core end surface, so as to overcome the influence of gravity, buoyancy and the specific surface area of ​​the core on the imbibition effect during the experiment, which is particularly important for accurately studying the imbibition recovery rate. The device can be used to study and evaluate the spontaneous imbibition effect of the imbibition agent, providing a theoretical indoor theoretical basis for field application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0034] Figure 1 It is a structural schematic diagram of the spontaneous imbibition experimental device of the utility model;

[0035] Figure 2 This is a detailed structural diagram of the core holder in the utility model;

[0036] Figure 3 for Figure 2 Right view of;

[0037] Figure 4 for Figure 2 A magnified cross-sectional view of the middle sealing inner sleeve;

[0038] Figure 5 for Figure 2 A magnified cross-sectional view of the middle gland;

[0039] In the figure: 1. horizontal flow pump; 2. imbibition agent container bottle; 3. imbibition agent injection tube; 4. imbibition agent injection valve; 5. imbibition metering bottle; 5a. volume scale; 6. sealing base; 7. core holder; 7a. annular pressure injection port; 7b. O-ring; 8. sealing rubber sleeve; 9. core; 10. sealing inner sleeve; 10a. inner sleeve outer flange; 10b. inner sleeve sealing ring; 11. pressure cover; 11a. pressure cover center hole; 11b. pressure cover countersunk hole; 12. annular pressure monitoring pump; 13. annular pressure pipeline; 14. annular pressure valve; 15. constant temperature box. DETAILED DESCRIPTION

[0040] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0041] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0043] like Figures 1 to 5 As shown, the imbibition agent spontaneous imbibition experimental device of the utility model includes a reaction and metering part, a core part and an imbibition agent part.

[0044] Reaction and metering part: including an infiltration metering bottle 5 located in a constant temperature box 15. The infiltration metering bottle 5 is in the shape of an inverted funnel. The inner wall of the bottle is treated with oleophobicity to prevent crude oil from sticking to the wall and affecting the accuracy of the experimental results. The lower end of the infiltration metering bottle 5 is provided with an internal thread at the bell mouth, and the outer periphery of the sealing base 6 is provided with an external thread and is screwed into the internal thread of the lower end of the infiltration metering bottle 5.

[0045] A measuring vertical tube extending upward is provided at the center of the upper port of the imbibition metering bottle 5, and a precise volume scale 5a is provided on the outer wall of the measuring vertical tube; the measuring accuracy is set according to the experimental requirements, and the volume of the imbibition oil can be read by the volume method.

[0046] Core part: The core holder 7 is cylindrical and its axis is parallel to the sealing base 6 and fixed on the sealing base 6. For example, the two ends of the core holder 7 are fixed to the upper end surface of the sealing base 6 by clamps. The core 9 is clamped in the core holder 7, and the outer periphery of the core 9 is wrapped with a sealing rubber sleeve 8 to seal the circumference of the core 9. The two ends of the sealing rubber sleeve 8 exceed the two ends of the core 9. The sealing rubber sleeve 8 is placed in the core holder 7 with a clearance fit, which is convenient for taking and placing the sealing rubber sleeve 8 in the core holder 7, and distilled water can be injected to establish annular pressure. The imbibition metering bottle 5 is filled with an imbibition agent, and only the two ends of the core 9 are exposed to contact with the imbibition agent.

[0047] A downwardly extending annular pressure injection port 7a is provided at the bottom of the middle section of the core clamp 7, the inner port of the annular pressure injection port 7a is communicated with the peripheral annular gap of the sealing rubber sleeve 8, and the lower end of the annular pressure injection port 7a passes through the central hole of the sealing base 6; an annular groove is provided on the outer wall of the middle section of the annular pressure injection port 7a, and an O-ring 7b is embedded in the annular groove to achieve sealing with the central hole of the sealing base 6.

[0048] The outlet of the annular pressure monitoring pump 12 is connected to the annular pressure injection port 7a through the annular pressure pipeline 13 and the annular pressure valve 14, so as to inject distilled water and build up pressure, so that the sealing rubber sleeve 8 is tightly wrapped around the outer periphery of the core 9 to ensure that the circumference of the core 9 does not contact the imbibition agent.

[0049] The two ends of the core holder 7 are respectively connected with sealing inner sleeves 10, and the circumferential wall of the sealing inner sleeve 10 is inserted into the port of the sealing rubber sleeve 8. The two ends of the sealing rubber sleeve 8 are pressed tightly against the inner walls of the two ports of the core holder 7 to seal the two ends of the space where the distilled water establishes annular pressure.

[0050] The inner end of the sealing inner sleeve 10 is provided with a circular chamfer to facilitate smooth insertion into the port of the sealing rubber sleeve 8. The inner port of the sealing inner sleeve 10 is pressed against the outer end surface of the core 9 to enable the core 9 to obtain axial positioning.

[0051] The outer ends of the sealing inner sleeve 10 are respectively provided with inner sleeve outer flanges 10a. When the steps of the inner sleeve outer flanges 10a abut against the outer ends of the core holder 7, the core is inserted into place and positioned.

[0052] The outer periphery of both ends of the core clamp 7 is respectively provided with a clamp external thread, and a pressure cap 11 is screwed on the clamp external thread. The middle inner step of the pressure cap 11 is pressed on the outer port of the core clamp 7. The center of the outer end surface of the pressure cap 11 is provided with a pressure cap center hole 11a that passes through the inner hole of the sealing inner sleeve. The outer inner step of the pressure cap 11 is pressed on the outer side of the inner sleeve outer flange 10a to press the sealing inner sleeve 10 to position it.

[0053] An inner sleeve sealing ring 10b is embedded in the outer periphery of the inner sleeve outer flange 10a to achieve sealing with the inner peripheral wall of the middle inner step of the pressure cover 11, further ensuring the sealing of the two ends of the ring press.

[0054] The outer end surface or the outer peripheral wall of the gland 11 is symmetrically provided with gland countersunk holes 11 b to facilitate the insertion of tools to remove or install the gland 11 .

[0055] Imbibing agent part: An imbibing agent container bottle 2 is also provided in the thermostatic box 15, the bottom inlet of the imbibing agent container bottle 2 is connected to the outlet of the horizontal flow pump 1, the top outlet of the imbibing agent container bottle 2 is connected to the imbibing agent injection tube 3, and the outlet of the imbibing agent injection tube 3 is inserted into the upper port of the metering vertical tube and is higher than the top scale line.

[0056] The operating steps of the spontaneous imbibition experiment using this device are as follows:

[0057] Step 1: Select the natural core or artificial core of the required simulation block and cut it into a standard cylindrical core with a size of φ2.5×5cm. Vacuum the artificial core, saturate it with simulated crude oil and mature it for 12 hours before use. The natural core needs to be washed with oil, then vacuumized, saturated with simulated crude oil and matured for 12 hours before use.

[0058] Step 2: Place a core of standard size in a sealing rubber sleeve 8, which is pre-placed in a core holder 7, leaving a distance between the two ends of the core and the two ends of the sealing rubber sleeve 8, insert the sealing inner sleeve 10 into the port of the sealing rubber sleeve 8, so that the port of the sealing rubber sleeve 8 expands and presses against the inner wall of the port of the core holder 7. At the same time, the inner end of the sealing inner sleeve 10 presses the outer edge of the end face of the core to position the core axially.

[0059] The core holder 7 is fixed as a whole on the sealing base 6, and the annular pressure injection port 7a extends from the through hole of the sealing base 6. Ensure the seal and place it in a thermostatic box 15. Figure 1 Connect the equipment and set the ring pressure through the ring pressure monitoring pump 12 and maintain it at 2 MPa.

[0060] Step 3: Start the horizontal flow pump 1 to press the imbibition agent in the imbibition agent container bottle 2 out and inject it into the imbibition metering bottle 5 through the imbibition agent injection tube 3 and the imbibition agent injection valve 4. Stop adding when the imbibition agent liquid level in the imbibition metering bottle 5 is level with the top of the volume scale 5a on the outer periphery of the metering vertical tube.

[0061] Step 4: During the experiment, the core holder 7 controls the contact surface between the core and the imbibition agent to be the left and right end surfaces of the cylindrical core. The thermostatic box 15 simulates the oil layer temperature and is kept at a constant temperature at the oil layer temperature until the imbibition equilibrium is reached. The drop of the liquid level is observed, and the volume scale 5a after the imbibition equilibrium is read. The volume of imbibition oil V1 and the volume of oil saturated into the core V0 are recorded. The imbibition recovery rate η of the imbibition agent under this condition is calculated according to the following formula:

[0062] η=(V1 / V0)×100%.

[0063] Example 1

[0064] The artificial core of the required simulation block was selected and cut into a standard cylindrical core with a size of φ2.5×5cm and a permeability of 40×10 -3 μm 2 The core was vacuumed, saturated with simulated crude oil and aged for 12 hours; the core was placed in the core holder 7, the sealing base 6 was fixedly connected to the bottom of the permeation metering bottle 5, and the seal was ensured, and the core was placed in a thermostatic box 15. Figure 1The equipment is connected as shown, the ring pressure is set to 2MPa, and the temperature of the thermostat 15 is set to 70°C. The imbibition agent 1# is added to the imbibition metering bottle 5 through the imbibition agent container bottle 2 and the imbibition agent injection valve 4. When the imbibition agent liquid level is equal to the upper scale of the imbibition metering bottle 5, the addition is stopped; the temperature is kept constant until the imbibition equilibrium is reached, and the volume of imbibition oil is recorded as 0.45mL, and the volume of oil saturated into the core is 2.9mL. The imbibition recovery factor η of the imbibition agent #1 under this condition is calculated to be 15.5%.

[0065] Example 2

[0066] The natural core of the target area was selected and cut into standard cylindrical cores with a size of φ2.5×5cm and a permeability of 45×10 -3 μm 2 The core was washed with oil, vacuumed, saturated with simulated crude oil and aged for 12 hours; the core was placed in the core holder 7, the sealing base 6 was fixedly connected to the bottom of the permeation metering bottle 5, and the seal was ensured, and the core was placed in a thermostatic box 15. Figure 1 The equipment is connected as shown, the ring pressure is set to 2MPa, and the temperature of the thermostat 15 is set to 82°C. The imbibition agent 2# is added to the imbibition metering bottle 5 through the imbibition agent container bottle 2 and the imbibition agent injection valve 4. When the imbibition agent liquid level is equal to the upper scale of the imbibition metering bottle 5, the addition is stopped; the temperature is kept constant until the imbibition equilibrium is reached, and the volume of imbibition oil is recorded as 0.72mL, and the volume of oil saturated into the core is 3.34mL. The imbibition recovery factor η of the imbibition agent #2 under this condition is calculated to be 21.6%.

[0067] Example 3

[0068] The natural core of the target block was selected and cut into standard cylindrical cores with a size of φ2.5×5cm and a permeability of 7.5×10 -3 μm 2 The core was washed with oil, vacuumed, saturated with simulated crude oil and aged for 12 hours; the core was placed in the core holder 7, the sealing base 6 was fixedly connected to the bottom of the permeation metering bottle 5, and the seal was ensured, and the core was placed in a thermostatic box 15. Figure 1 The equipment is connected as shown, the ring pressure is set to 2MPa, and the temperature of the thermostat 15 is set to 65°C. The imbibition agent 3# is added to the imbibition metering bottle 5 through the imbibition agent container bottle 2 and the imbibition agent injection valve 4. When the imbibition agent liquid level is equal to the scale on the imbibition metering bottle 5, the addition is stopped; the temperature is kept constant until the imbibition equilibrium is reached, and the volume of imbibition oil removed is recorded as 0.14mL, and the volume of oil saturated into the core is 1.59mL. The imbibition recovery factor η of the imbibition agent #2 under this condition is calculated to be 8.8%.

[0069] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A spontaneous imbibition experimental device for an imbibition agent, comprising a constant temperature box, characterized in that: An infiltration metering bottle is provided in the thermostatic box. The infiltration metering bottle is in the shape of an inverted funnel and a sealing base is provided at the lower end. A core holder is fixed on the sealing base. A core is clamped in the core holder. The circumference of the core is sealed and both ends are exposed. An infiltration agent is injected into the infiltration metering bottle. A metering vertical tube extending upward is provided at the center of the upper end of the infiltration metering bottle, and the outer wall of the metering vertical tube is provided with a volume scale of the infiltration metering bottle.

2. The spontaneous imbibition experimental device of imbibition agent according to claim 1, characterized in that: The thermostatic box is also provided with an imbibition agent container bottle, the bottom inlet of the imbibition agent container bottle is connected to the outlet of the horizontal flow pump, the top outlet of the imbibition agent container bottle is connected to the imbibition agent injection tube, and the outlet of the imbibition agent injection tube is inserted into the upper port of the metering vertical tube and is higher than the top scale line.

3. The spontaneous imbibition experimental device of imbibition agent according to claim 1, characterized in that: The core holder is cylindrical and its axis is parallel to the sealing base.

4. The spontaneous imbibition experimental device of imbibition agent according to claim 1, characterized in that: The lower port of the absorption metering bottle is provided with an internal thread, and the outer periphery of the sealing base is provided with an external thread which is screwed into the internal thread of the lower port of the absorption metering bottle.

5. The spontaneous imbibition experimental device of imbibition agent according to claim 2, characterized in that: The outer circumference of the core is wrapped with a sealing rubber sleeve, two ends of the sealing rubber sleeve extend beyond two ends of the core, and the sealing rubber sleeve is placed in the core holder with clearance fit.

6. The spontaneous imbibition experimental device of imbibition agent according to claim 5, characterized in that: The core clamp is fixed on the upper end surface of the sealing base, and a downwardly extending annular pressure injection port is provided at the bottom of the middle section of the core clamp, the inner port of the annular pressure injection port is communicated with the peripheral annular gap of the sealing rubber sleeve, and the lower end of the annular pressure injection port passes through the central hole of the sealing base and is sealed with each other.

7. The spontaneous imbibition experimental device of imbibition agent according to claim 6, characterized in that: An annular groove is provided on the outer wall of the middle section of the annular pressure injection port, and an O-ring is embedded in the annular groove to achieve sealing with the central hole of the sealing base.

8. The spontaneous imbibition experimental device of imbibition agent according to claim 6, characterized in that: The outlet of the ring pressure monitoring pump is connected to the ring pressure injection port through a ring pressure pipeline and a ring pressure valve.

9. The spontaneous imbibition experimental device of imbibition agent according to claim 6, characterized in that: The two ends of the core holder are respectively plugged with sealing inner sleeves, the circumferential wall of the sealing inner sleeve abuts against the sealing rubber sleeve to press the two ends of the sealing rubber sleeve against the inner walls of the two ports of the core holder, and the inner port of the sealing inner sleeve presses the outer end surface of the core.

10. The spontaneous imbibition experimental device of imbibition agent according to claim 9, characterized in that: The outer ports of the sealing inner sleeve are respectively provided with inner sleeve outer flanges, and the steps of the inner sleeve outer flanges respectively abut against the outer ports of the core holder.

11. The spontaneous imbibition experimental device of imbibition agent according to claim 9, characterized in that: The inner end of the sealing inner sleeve is provided with a circular arc chamfer.

12. The spontaneous imbibition experimental device of imbibition agent according to claim 10, characterized in that: The outer periphery of both ends of the core clamp is respectively provided with a clamp external thread, and a pressure cap is screwed on the clamp external thread, and the middle inner step of the pressure cap is pressed on the outer port of the core clamp, and the center of the outer end surface of the pressure cap is provided with a pressure cap center hole that passes through the inner hole of the sealing inner sleeve, and the outer inner step of the pressure cap is pressed on the outer side of the outer flange of the inner sleeve.

13. The spontaneous imbibition experimental device of imbibition agent according to claim 12, characterized in that: An inner sleeve sealing ring is embedded in the outer periphery of the outer flange of the inner sleeve to achieve sealing with the inner peripheral wall of the middle inner step of the gland.

14. The spontaneous imbibition experimental device of imbibition agent according to claim 12, characterized in that: The outer end surface or the outer peripheral wall of the gland is symmetrically provided with gland countersunk holes for disassembly and assembly.

15. The spontaneous imbibition experimental device of any one of claims 1 to 14, characterized in that: The two ends of the core holder are respectively fixed to the upper end surface of the sealing base through clamps.

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