Visual fractured low-permeability reservoir foam flooding experimental device and method

Abstract

The invention discloses a visual fractured low-permeability reservoir foam flooding experimental device and method. One end of the intermediate container is connected with the kettle body through a pipeline; the gas meter is connected with the gas-liquid separator; one end of the nitrogen container is connected with the kettle body; the visual window is arranged on the kettle body; a rock core placing device is arranged in the kettle body, and the intermediate container comprises a formation water container, a simulated oil sample container, an experimental gas sample container and a foaming agent water sample container which are connected in parallel; a high-definition camera is arranged on the outer side of the visual window, and an X-ray emitter is arranged beside the kettle body. According to the invention, production optimization can be carried out when foam flooding is carried out on the fractured low-permeability reservoir, and the method can be used for carrying out related physical simulation experiments of the fractured low-permeability reservoir indoors. The foaming condition of in-situ foam generated after a foaming agent is injected into a rock core and passes through reservoirs with different permeability can be observed, and the profile control and water plugging condition of foam flooding can be evaluated by analyzing the distribution of remaining oil in the reservoirs.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and natural gas exploration and development, and in particular relates to a visualized fractured low-permeability reservoir foam flooding experimental device and method. Background Art

[0002] Fractured low-permeability reservoirs are widely distributed around the world and are an important part of oil and gas resources. This type of reservoir has extremely strong heterogeneity, and the connections within and between reservoirs are complex. Currently, foam flooding has become an effective way to improve the recovery of such reservoirs. When foam seeps in the medium, due to its unique fluid properties, it can increase the swept volume of the injected fluid and improve the oil washing efficiency while selectively plugging the high-permeability layer, which is of great significance for the prevention and control of crossflow during the displacement process and the efficiency of oil field development.

[0003] At present, there are related methods for indoor foam flooding, with the patent publication number CN109707352A, and the patent name is Patent application for experimental device and experimental method for determining nitrogen and nitrogen foam assisted gravity flooding efficiency. An experimental device for determining nitrogen and nitrogen foam assisted gravity flooding has a simulated core, including an injection system, a temperature control system, a back pressure control system and a data acquisition system, and an experimental method is designed based on the above experimental device, which can effectively determine the difference in crude oil recovery between nitrogen assisted gravity drive and nitrogen and nitrogen foam assisted gravity drive, and provide guidance for methods to increase recovery through gas drive and chemical drive. However, the model design of the device is too simplified, and there is no test to compare the oil recovery effect under the influence of different permeabilities.

[0004] The patent application with the patent publication number CN110761759A and the patent name of "An experimental device for foam flooding effect in fracture-cavity bottom water reservoir" disclosed that the theoretical calculation of the foam flooding process under different fracture width conditions was carried out under the condition of realizing fracture and matrix diversion, but the experimental results failed to well reflect the distribution of residual oil in the core. The patent application with the patent publication number CN110714756A and the patent name of "A high-temperature and high-pressure X-CT scanning fracture-cavity physical model" disclosed that the fracture-cavity model can observe and record the flow status of the fluid and the distribution of oil, gas and water in the model in real time during the displacement process, but failed to truly and effectively observe the generation of in-situ foam in the reservoir when applied to the foam flooding production method. Summary of the invention

[0005] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a visualized fractured low-permeability oil reservoir foam flooding experimental device and method, so that production optimization can be carried out when foam flooding is carried out for fractured low-permeability oil reservoirs, and the foaming of in-situ foam generated after the foaming agent is injected into the core and passes through reservoirs with different permeabilities can be truly observed, and the profile adjustment and water plugging of foam flooding can be evaluated by analyzing the distribution of residual oil in the reservoir.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A visualized high-temperature and high-pressure in-situ foam generating device, comprising:

[0008] A kettle body, wherein the kettle body is provided with a fluid injection port, a fluid extraction port and a confining pressure injection port;

[0009] An intermediate container, one end of which is connected to the fluid injection port of the kettle body through a pipeline, and the other end of which is connected to a displacement pump;

[0010] A back-pressure valve, the back-pressure valve being connected to the fluid extraction port of the kettle body through a pipeline;

[0011] A gas-liquid separator, the gas-liquid separator is connected to the back-pressure valve through a pipeline;

[0012] A gas meter connected to the gas-liquid separator via a pipeline;

[0013] A nitrogen container, one end of which is connected to the confining pressure injection port of the kettle body, and the other end of which is connected to a confining pressure pump;

[0014] A visualization window, wherein the visualization window is arranged on the kettle body;

[0015] Among them, a core placing device is arranged inside the kettle body, and the intermediate container includes a formation water container, a simulated oil sample container, an experimental gas sample container and a foaming agent water sample container which are connected in parallel with each other; a high-definition camera is placed outside the visualization window, and an X-ray transmitter is placed next to the kettle body.

[0016] Optionally, the high-definition camera and the X-ray transmitter are both connected to a computer.

[0017] Optionally, the core placement device includes two steel frames and a plurality of arched steel bars, the two steel frames are symmetrically arranged about the central axis of the kettle body, both ends of the steel frames are connected to the end of the kettle body, and both ends of the arched steel bars are respectively connected to the two steel frames.

[0018] Optionally, the plurality of arched steel bars are parallel to each other, and the distance between the arched steel bars matches the diameter of the core.

[0019] Optionally, a heating belt is wrapped around the kettle body.

[0020] Optionally, there are two visualization windows, which are respectively arranged at the top and the bottom of the kettle body, and the two visualization windows are symmetrically arranged about the central axis of the kettle body.

[0021] Optionally, a light source is provided below the visualization window at the bottom of the kettle body.

[0022] Optionally, the high-definition camera is arranged above the visualization window on the top of the kettle body.

[0023] Optionally, pressure gauges are provided on the pipeline connecting the kettle body and the intermediate container and the pipeline connecting the kettle body and the nitrogen container.

[0024] A method for using a visualized high-temperature and high-pressure in-situ foam generating device comprises the following steps:

[0025] S1: placing a number of cores in the core placing device of the kettle;

[0026] S2: Use a displacement pump to inject the simulated oil sample in the simulated oil sample container into the core, close the valve connected to the intermediate container, use an X-ray emitter to scan the core, and record the initial oil saturation image in the core;

[0027] S3: Open the valve connected to the formation water container, use the displacement pump to inject the formation water in the formation water container into the core, displace the simulated oil in the core, observe through the gas-liquid separator until no oil can be displaced, close the valve connected to the formation water container, use the X-ray emitter to scan the core, and record the oil phase distribution image in the core after water flooding;

[0028] S4: Open the valves connected to the experimental gas sample container and the foaming agent water sample container, use a displacement pump to inject the experimental gas in the experimental gas sample container and the water sample containing the foaming agent in the foaming agent water sample container into the core, observe and record the generation of in-situ foam after passing through the core through a visualization window and a high-definition camera, then close the valves connected to the experimental gas sample container and the valves connected to the foaming agent water sample container, use an X-ray emitter to scan the core, and record the oil phase distribution image in the core after the foam is injected;

[0029] S5: Open the valve connected to the formation water container, and use the displacement pump to inject the formation water in the formation water container into the core for oil displacement. During the process, an X-ray emitter is used to scan the core every time a certain amount of formation water is injected to record the oil phase distribution image in the core. The displacement is terminated when no oil is produced by observing through the gas-liquid separator.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention discloses a visualized fractured low-permeability oil reservoir foam flooding experimental device. By arranging a formation water container, a simulated oil sample container, an experimental gas sample container and a foaming agent water sample container, the device can optimize production when foam flooding is carried out for fractured low-permeability oil reservoirs. The device can be used to carry out relevant physical simulation experiments of fractured low-permeability oil reservoirs indoors and guide the development of fractured low-permeability oil reservoirs by foam flooding.

[0032] Another object of the present invention is to provide an experimental method for visualizing the occurrence of in-situ foam and dynamically monitoring the oil recovery effect using the above-mentioned device, which can not only truly observe the foaming of in-situ foam generated after the foaming agent is injected into the core and passes through reservoirs with different permeabilities, but also evaluate the profile adjustment and water plugging of foam oil recovery by analyzing the distribution of residual oil in the reservoir. This method makes up for the invisible and non-in-situ characteristics of the foam injection process and the deficiencies and defects in the description of the distribution of residual oil in the core during the oil recovery process.

[0033] Furthermore, the present invention provides a steel frame and a bow-shaped steel bar for fixing the core inside the kettle body, so that the core can be fixed more stably during the experiment.

[0034] Furthermore, a heating belt is wound around the kettle body of the present invention, so as to facilitate heating of the kettle body. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are for explanation purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

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

[0037] Figure 2 It is a cross-sectional view of the interior of the kettle body of the present invention;

[0038] Figure 3 This is a front view of the bow-shaped steel bar of the present invention;

[0039] Figure 4 It is a left view of the bow-shaped steel bar of the present invention;

[0040] Among them, 1-displacement pump, 2-confining pressure pump, 3-formation water container, 4-simulated oil sample container, 5-experimental gas sample container, 6-foaming agent water sample container, 7-nitrogen container, 8-kettle body, 9-warming zone, 10-visualization window, 11-electric pulley, 12-X-ray transmitter, 13-computer, 14-high-definition camera, 15-light source, 16-back pressure valve, 17-gas-liquid separator, 18-gas meter, 19-steel frame, 20-core, 21-bow steel bar, 211-connecting plate, 212-arc plate, 22-threaded perforation. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0042] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only embodiment.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein 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. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0044] The present invention is described in detail below with reference to the accompanying drawings.

[0045] like Figure 1 and Figure 2 As shown, a visualized fractured low-permeability oil reservoir foam flooding experimental device of the present invention comprises: a displacement pump 1, a confining pressure pump 2, an intermediate container, a nitrogen container 7, a kettle body 8, a heating belt 9, an X-CT scanning system, a high-definition camera 14, a light source 15, a back pressure valve 16, a gas-liquid separator 17 and a gas meter 18.

[0046] The kettle body 8 includes a kettle body, and a kettle cover is arranged at the end of the kettle body. A plurality of mounting holes are arranged at the connection between the kettle cover and the kettle body, and bolts are installed in the mounting holes for connecting and sealing the kettle body 8. An annular groove is arranged at the connection between the kettle cover and the kettle body, and a sealing ring is arranged in the annular groove for further sealing the entire kettle body 8.

[0047] Optionally, the kettle body 8 is a hollow cylinder.

[0048] Optionally, an electric pulley 11 is installed at the bottom of the kettle body 8 to control the movement of the kettle body 8.

[0049] Specifically, the kettle cover end of the kettle body 8 is provided with a fluid injection port, a fluid extraction port and a confining pressure injection port.

[0050] The fluid injection port is connected to the intermediate container through a pipeline, and the intermediate container includes a formation water container 3, a simulated oil sample container 4, an experimental gas sample container 5 and a foaming agent water sample container 6, and the formation water container 3, the simulated oil sample container 4, the experimental gas sample container 5 and the foaming agent water sample container 6 are connected in parallel. The other end of the intermediate container is connected to the displacement pump 1. The gas in the experimental gas sample container 5 can be injected into the core 20 together with the foaming agent in the foaming agent water sample container 6 during the experiment to mix and generate foam, which plays a role in blocking part of the flow channels in the core 20.

[0051] Confining pressure injection ports are correspondingly arranged on the inner and outer sides of the kettle cover, and the confining pressure injection ports can be used for pressure relief.

[0052] The fluid extraction port is connected to the back pressure valve 16 through a pipeline, the other end of the back pressure valve 16 is connected to the gas-liquid separator 17 through a pipeline, and the gas meter 18 is connected to the gas-liquid separator 17 through a pipeline. The gas-liquid separator 17 is used to collect and separate gas and liquid after the experiment.

[0053] Optionally, pressure gauges are provided on both the pipeline connected to the fluid injection port and the pipeline connected to the fluid extraction port.

[0054] The confining pressure injection port is connected to the nitrogen container 7 through a pipeline, and the other end of the nitrogen container 7 is connected to the confining pressure pump 2. The nitrogen container 7 is used to apply confining pressure to the kettle body 8.

[0055] The top and bottom of the kettle body are both provided with visualization windows 10, and the visualization windows 10 are inlaid with thickened organic glass matching the visualization windows 10, and the two visualization windows 10 are arranged opposite to each other. Optionally, the visualization windows 10 are square.

[0056] A steel frame 19 is provided inside the kettle cover, one end of the steel frame 19 is in contact with the inner wall of the kettle body, and a circular steel plate is provided at the other end, the diameter of the circular steel plate is equal to the diameter of the kettle cover. A fluid extraction end interface is provided on the circular steel plate. The fluid extraction end interface is connected to the fluid extraction port through a steel pipeline.

[0057] Optionally, the steel frame 19 is rectangular, wherein the short side of the steel frame 19 is connected to the kettle body 8 .

[0058] A heating belt 9 is wound around the outside of the kettle body 8 to control the experimental temperature inside the kettle body 8 .

[0059] Specifically, the steel frame 19 is welded on the inner wall of the kettle body. There are two steel frames 19, and the two steel frames 19 are symmetrically arranged about the central axis of the kettle body. The length of the steel frame 19 is L, and the thickness is H.

[0060] The steel frame 19 is evenly distributed with threaded holes, and the steel frame 19 is connected with a bow-shaped steel bar 21 through the holes. The bow-shaped steel bar 21 is arc-shaped, and one end of the bow-shaped steel bar 21 is connected to the steel frame 19 at the top of the kettle body, and the other end is connected to the steel frame 19 at the bottom of the kettle body. A plurality of cores 20 are arranged in the steel frame 19, and the two sides of the core 20 are fixed by two of the bow-shaped steel bars 21.

[0061] Preferably, the shape of the arched steel bar 21 matches the inner wall of the kettle body.

[0062] Optionally, the number of the bow-shaped steel bars 21 is 12, and every two bow-shaped steel bars 21 form a group, wherein one group of the bow-shaped steel bars 21 is arranged at the end of the kettle body away from the kettle cover, and the distance between each group of the other 5 groups of bow-shaped steel bars 21 matches the length of the core 20, and the intervals between each group are the same.

[0063] Specifically, the arched steel bar 21 includes an arc plate 212, and the two ends of the arc plate 212 are connected to connecting plates 211. The arc plate 212 is a semi-circular plate, and a 90° chamfer is provided in the middle of the arc plate 212 for fixing the cores 20 with different permeabilities. The connecting plates 211 at both ends of the arched steel bar 21 are provided with threaded through holes 22, and the threaded through holes 22 are fixed to the threaded through holes on both sides of the steel frame 19 by screws and nuts.

[0064] Specifically, three micro-fracture cores 20 with permeabilities k1, k2, and k3 are placed in sequence in the steel frame 19 and fixed with chamfered bow-shaped steel bars 21. The cavity between the cores 20 is used to observe the foam generation process.

[0065] Optionally, the core 20 is a cylinder. The core 20 is synthesized by an artificial synthesis method, and the grinding parameters of the core 20 are set to L / 4 according to the length L of the steel frame 19. The core 20 is cut and split along the axial direction, and the cracks are formed by embedding the symmetrically split core 20 through an impermeable, high-temperature and oil-resistant polytetrafluoroethylene liner, and the embedding surface is symmetrically etched with micro cracks of different sizes by a laser etcher.

[0066] The X-CT scanning system includes a computer 13 and an X-ray transmitter 12. The computer 13 controls the movement of the electric pulley 11 to send the entire kettle body 8 into the X-ray transmitter 12 to complete the scanning of the fluid in the kettle body 8, and the fluid distribution in the core 20 is displayed on the computer 13. Among them, a high-definition camera 14 is arranged above the visualization window 10 at the top of the kettle body, and a light source 15 is arranged below the visualization window 10 at the bottom of the kettle body for emitting and receiving light sources. The high-definition camera 14 is connected to the computer 13 to observe and record the flow conditions of the fluid in the kettle body 8. Preferably, the pixel requirement of the high-definition camera 14 is not less than 1.3 million, and the maximum resolution requirement is not less than 1920*1080.

[0067] Compared with the prior art, the present invention has certain feasibility and operability. It can not only observe in real time the foaming effect of the foaming agent through the core 20 with different permeabilities after being injected into the rock plate, but also can timely observe and analyze the distribution of the oil phase in the core 20, thereby reflecting the profile adjustment and water plugging effect of foam oil recovery, and providing technical support for the adjustment of subsequent development measures.

[0068] The visual fractured low-permeability oil reservoir foam flooding experimental device of the present invention comprises the following steps when in use:

[0069] After the prepared core 20 is placed in the steel frame 19 and sealed, the devices are connected in sequence, and the simulated oil sample in the simulated oil sample container 4 is injected into the core 20 at a certain flow rate using the displacement pump 1. At the same time, the nitrogen in the intermediate container is injected into the kettle body 8 through the confining pressure injection port on the kettle body 8 using the displacement pump 1 to apply confining pressure to the core 20. During the injection process, the confining pressure is always kept higher than the pressure at the production outlet of the kettle body 8 by 2 MPa until the pressure at the production outlet is equal to the pressure P required for the experiment.

[0070] The valve connecting the intermediate container is closed, and the core 20 is scanned using an X-CT scanning system to record an initial oil saturation image in the core 20 .

[0071] Then, the valve connected to the formation water container 3 is opened, and the displacement pump 1 is used to inject the formation water in the formation water container 3 into the core 20 at a certain flow rate to displace the simulated oil in the core 20. The simulated oil in the core 20 is displaced by observing through the gas-liquid separator 17 until no oil can be displaced. The valve connected to the formation water container 3 is closed, and the core 20 is scanned using an X-CT scanning system. The oil phase distribution image in the core 20 after water flooding is recorded in the computer 13.

[0072] At the same time, the valve connecting the experimental gas sample container 5 and the foaming agent water sample container 6 is opened, and the experimental gas and the water sample containing the foaming agent in the experimental gas sample container 5 and the foaming agent water sample container 6 are injected into the core 20 at a certain flow rate by using the displacement pump 1. The water sample containing the foaming agent and the experimental gas are mixed in the core 20 to produce in-situ foam to block part of the flow channels in the core 20. The generation of in-situ foam after passing through the fractured core 20 with different permeabilities is observed and recorded through the visualization window 10 and the high-definition camera 14. Then, the valve connecting the experimental gas sample container 5 and the foaming agent water sample container 6 is closed, and the core 20 is scanned by using the X-CT scanning system to record the oil phase distribution image in the core 20 after the foam is injected.

[0073] Finally, the valve connected to the formation water container 3 is opened, and the formation water in the formation water container 3 is injected into the core 20 at a certain flow rate using the displacement pump 1 for oil displacement. During the process, the entire core 20 is scanned using the X-CT scanning system for each 0.5 ml of formation water injected, and the oil phase distribution image in the core 20 is recorded. The displacement is terminated by observing through the gas-liquid separator 17 until no oil is produced, and the experiment is terminated. The obtained saturation images are compared and analyzed to select the permeability range with the best in-situ foaming effect, and the plugging ability of the foam on the high permeability layer is evaluated, providing a reference for actual production of foam injection oil displacement.

[0074] Example

[0075] Combine the following Figure 1 and Figure 2 The specific implementation modes of the present invention are further described.

[0076] In this embodiment, quartz sand with mesh sizes of 30-40, 50-70, and 70-140 are respectively mixed with AB glue whose main components are acrylic acid, epoxy, and polyurethane according to the equal volume compression method, and after being air-dried, three groups of cores 20 with different permeabilities are made by grinding.

[0077] First, the core 20 is placed in an intermediate container, and the core 20 and the intermediate container are evacuated. Then, formation water is injected into the intermediate container and pressurized for 48 hours to make the core 20 completely saturated with formation water.

[0078] After the core 20 is saturated with water, three groups of cores 20 with microcracks are assembled in the cavity of the kettle cover with the steel frame 19, and the core 20 is fixed with a chamfered arched steel bar 21, and a 5mm thick PVC transparent soft glass (mainly composed of polyvinyl chloride) is pasted on the surface of the arched steel bar 21 and the core 20 for sealing, and then silicone rubber is applied around the steel frame 19 for further sealing, and finally the entire kettle body 8 is assembled and sealed with bolts;

[0079] The entire kettle 8 is evacuated by a vacuum pump, and the temperature is raised to the desired experimental temperature by the heating belt 9 on the surface of the kettle 8, and then the light source 15 is turned on, and the high-definition camera 14 is used to start recording. The vacuum pump here refers to a device or equipment that uses mechanical, physical, chemical or physicochemical methods to evacuate the container to obtain a vacuum.

[0080] Use the displacement pump 1 to add confining pressure to a certain pressure through the confining pressure injection port of the kettle body 8, open the container 4 containing the simulated oil sample, use silicone oil and iodinated n-butane in a 3:1 mixture, and use the displacement pump 1 to inject the fluid into the core 20 through the fluid injection port of the kettle body 8 at a certain speed until the pressure at the production outlet is equal to the pressure P required for the experiment, thereby completing the pressure establishment of the entire system. During the pressure building process, the confining pressure is always kept greater than the production outlet pressure by 2MPa, and the back pressure is gradually increased to equal to P through the back pressure valve 16. After the pressure building is completed, the entire kettle body 8 is scanned using an X-CT scanning system, and the distribution of the oil phase in the core 20 is recorded in the computer 13.

[0081] Open the formation water container 3, use the displacement pump 1 to inject the formation water sample into the kettle 8 at a certain speed to displace the simulated oil in the core 20 until no oil can be produced, then use the X-CT scanning system to scan the entire kettle 8, and the computer 13 records the distribution of the oil phase in the core 20.

[0082] At the same time, the experimental gas sample container 5 and the foaming agent water sample container 6 are opened, and the foaming agent is injected into the kettle body 8 at a certain speed using the displacement pump 1. The generation of in-situ foam produced by the foaming agent after passing through the core 20 with different permeabilities is recorded using the high-definition camera 14 through the visualization window 10 on the surface of the kettle body 8.

[0083] The formation water container 3 is opened, and the displacement pump 1 is used to inject the formation water sample into the kettle 8 at a certain speed to displace the simulated oil in the core 20. During the entire displacement process, the entire kettle 8 is scanned by the X-CT scanning system every time 0.5 ml of formation water is injected, and the distribution of the oil phase in the core 20 is recorded by the computer 13 until no oil can be produced. Finally, the distribution characteristics of the oil phase in the core 20 during the displacement process are comprehensively analyzed based on the recorded results to reflect the sealing effect of foam injection on fractures and high permeability layers.

[0084] Unless otherwise specified, the device elements involved in the above embodiments are all conventional device elements, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A visualized high-temperature and high-pressure in-situ foam generating device, characterized in that: include: A kettle body (8), wherein the kettle body (8) is provided with a fluid injection port, a fluid extraction port and a confining pressure injection port; an intermediate container, one end of which is connected to the fluid injection port of the kettle (8) through a pipeline, and the other end of which is connected to a displacement pump (1); A back-pressure valve (16), the back-pressure valve (16) being connected to the fluid extraction port of the kettle body (8) via a pipeline; A gas-liquid separator (17), wherein the gas-liquid separator (17) is connected to the back-pressure valve (16) via a pipeline; A gas meter (18), the gas meter (18) being connected to the gas-liquid separator (17) via a pipeline; A nitrogen container (7), one end of the nitrogen container (7) is connected to the confining pressure injection port of the kettle body (8), and the other end is connected to the confining pressure pump (2); A visualization window (10), wherein the visualization window (10) is arranged on the kettle body (8); A core placing device is arranged inside the kettle body (8), and the intermediate container comprises a formation water container (3), a simulated oil sample container (4), an experimental gas sample container (5) and a foaming agent water sample container (6) which are connected in parallel with each other; a high-definition camera (14) is placed outside the visualization window (10), and an X-ray transmitter (12) is placed next to the kettle body (8).

2. A visualized high-temperature and high-pressure in-situ foam generating device according to claim 1, characterized in that: The high-definition camera (14) and the X-ray transmitter (12) are both connected to a computer (13).

3. A visualized high-temperature and high-pressure in-situ foam generating device according to claim 1, characterized in that: The core placement device comprises two steel frames (19) and a plurality of arched steel bars (21), wherein the two steel frames (19) are symmetrically arranged about the central axis of the kettle body (8), both ends of the steel frames (19) are connected to the ends of the kettle body (8), and both ends of the arched steel bars (21) are respectively connected to the two steel frames (19).

4. A visualized high-temperature and high-pressure in-situ foam generating device according to claim 3, characterized in that: The plurality of arched steel bars (21) are parallel to each other, and the distance between the arched steel bars (21) matches the diameter of the core (20).

5. The visualized high-temperature and high-pressure in-situ foam generating device according to claim 1, characterized in that: A heating belt (9) is wound around the kettle body (8).

6. The visualized high-temperature and high-pressure in-situ foam generating device according to claim 1, characterized in that: The number of the visualization windows (10) is two, and they are respectively arranged at the top and the bottom of the kettle body (8), and the two visualization windows (10) are symmetrically arranged about the central axis of the kettle body (8).

7. A visualized high-temperature and high-pressure in-situ foam generating device according to claim 6, characterized in that: A light source instrument (15) is arranged below the visualization window (10) at the bottom of the kettle body (8).

8. The visualized high-temperature and high-pressure in-situ foam generating device according to claim 6, characterized in that: The high-definition camera (14) is arranged above the visualization window (10) on the top of the kettle body (8).

9. The visualized high-temperature and high-pressure in-situ foam generating device according to claim 1, characterized in that: Pressure gauges are provided on the pipeline connecting the kettle body (8) and the intermediate container and on the pipeline connecting the kettle body (8) and the nitrogen container (7).

10. A method for using a visualized high-temperature and high-pressure in-situ foam generating device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: placing a plurality of cores (20) in a core placing device of a kettle body (8); S2: using a displacement pump (1) to inject the simulated oil sample in the simulated oil sample container (4) into the core (20), closing the valve connected to the intermediate container, using an X-ray emitter (12) to scan the core (20), and recording an initial oil saturation image in the core (20); S3: opening the valve connected to the formation water container (3), using the displacement pump (1) to inject the formation water in the formation water container (3) into the core (20), displacing the simulated oil in the core (20), observing through the gas-liquid separator (17) until no oil can be driven out, closing the valve connected to the formation water container (3), using the X-ray emitter (12) to scan the core (20), and recording the oil phase distribution image in the core after water flooding; S4: Open the valve connected to the experimental gas sample container (5) and the valve connected to the foaming agent water sample container (6), use the displacement pump (1) to inject the experimental gas in the experimental gas sample container (5) and the water sample containing the foaming agent in the foaming agent water sample container (6) into the core (20), observe and record the generation of in-situ foam after passing through the core (20) through the visualization window (10) and the high-definition camera (14), then close the valve connected to the experimental gas sample container (5) and the valve connected to the foaming agent water sample container (6), use the X-ray emitter (12) to scan the core (20), and record the oil phase distribution image in the core (20) after the foam is injected; S5: Open the valve connected to the formation water container (3), use the displacement pump (1) to inject the formation water in the formation water container (3) into the core (20) for oil displacement. During the process, every time a certain amount of formation water is injected, the core (20) is scanned using an X-ray emitter (12) to record the oil phase distribution image in the core (20). The displacement is terminated when the oil is no longer discharged after observation through the gas-liquid separator (17).

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