Microscopic visualization of two-phase flow displacement experiment system and method for underground reservoir

Abstract

This invention relates to a microscopic visualization experimental system and method for two-phase flow displacement in underground reservoirs. The system includes: a microscopic flow chip and, sequentially connected, an injection module, a microscopic clamp, a pressure and temperature acquisition and control module, a gas metering module, and a data and image acquisition module. The microscopic flow chip is held within the microscopic clamp. The injection module includes an N2 gas cylinder, a hydrogen generator, a piston container, an injection pump, and a pressure regulating valve. The pressure and temperature acquisition and control module includes an annular pressure tracking pump, a back pressure unit, a temperature sensor, and a heating unit. The back pressure unit includes a back pressure valve, a back pressure container, and a back pressure pump. Compared with existing technologies, this invention allows for direct observation of the two-phase flow in the model and the distribution of the residual gas phase after gas-driven water, water-driven gas, polymer-driven, and other chemical-driven displacement processes, while ensuring the accuracy of experimental data.

Description

Technical Field

[0001] This invention relates to the technical field of multiphase flow simulation experimental devices for underground reservoirs, and in particular to a microscopic visualization experimental system and method for two-phase flow displacement in underground reservoirs. Background Technology

[0002] For underground hydrogen storage in porous reservoirs, its feasibility largely depends on the flow and transport behavior of hydrogen. The injection and extraction cycles within the reservoir are controlled by complex pore-scale processes. Researchers have observed that when attempting to simulate hydrogen storage in sandstone reservoirs, hydrogen primarily occupies macropores, while micropores, pore throats, and corners are occupied by brine due to hydrogen's high water wettability. Pore-level observations have provided strong preliminary evidence that saline aquifers in sandstone reservoirs are favorable for hydrogen storage. However, research in my country on the factors influencing the two-phase displacement process of hydrogen and brine, and which changes would improve hydrogen storage efficiency, remains limited. Therefore, designing a microscopically visualized experimental device for two-phase flow displacement in underground reservoirs to directly observe the entire seepage process of brine and hydrogen displacement under different conditions is crucial for studying the quantitative relationship between hydrogen storage capacity and pore network structural parameters, multiphase flow field parameters, and establishing predictive models for hydrogen storage efficiency under complex reservoir conditions.

[0003] Chinese patent CN112630407 discloses a microscopic visualization simulation experimental device and method for sand production in hydrate reservoirs. This device can simulate sand production during natural gas hydrate extraction, allowing direct observation of the entire microscopic migration process of fine particles driven by a gas-liquid mixed multiphase fluid, thus analyzing sand production patterns and studying the sand production mechanism of hydrate reservoirs. However, this design cannot observe and quantify the seepage of the gas-liquid two-phase flow in the model at a more microscopic level, nor can it reveal the residual gas phase distribution after gas-driven water, water-driven gas, polymer flooding, or other chemical flooding. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the existing technology and provide a microscopic visualization experimental system and method for two-phase flow displacement of underground reservoirs. The device of this invention can intuitively observe the seepage of two-phase flow in the model and the distribution of residual gas phase after gas-driven water, water-driven gas, polymer-driven and other chemical-driven displacement.

[0005] This invention provides a microscopic visualization experimental system for two-phase flow displacement of underground reservoirs, comprising: a microscopic seepage chip and sequentially connected injection module, microscopic holder, pressure and temperature acquisition and control module, gas metering module, and data and image acquisition module;

[0006] The micro-permeation chip is held within the micro-gripper;

[0007] The injection module includes an N2 gas cylinder, a hydrogen generator, a piston container, an injection pump, and a pressure regulating valve. The N2 gas cylinder and the hydrogen generator are both connected to the pressure regulating valve. The piston container can hold two different liquids. The piston container is connected to the injection pump to inject the two different liquids into the micro-percolation chip respectively. A first gas flow meter and a one-way valve are installed between the pressure regulating valve and the piston container.

[0008] The pressure and temperature acquisition and control module includes: a ring pressure tracking pump, a back pressure unit, a temperature sensor, and a heating unit. The back pressure unit includes: a back pressure valve, a back pressure container, and a back pressure pump. The vacuum pump, back pressure valve, back pressure container, and back pressure pump are connected in sequence through pipelines. Pressure sensors and valves are installed between each pair of the vacuum pump, back pressure valve, back pressure container, and back pressure pump. The heating device includes a semi-open insulation jacket and an electric heating jacket, which are built into a micro-clamp.

[0009] The gas metering module includes a flow meter group consisting of a second gas flow meter, a desiccant, and a gas-liquid separator connected in sequence.

[0010] The data and image acquisition module includes: pressure sensors, digital display instruments, data acquisition cards, oil displacement light sources, stereo microscopes, and computers, with the stereo microscope lens aligned with the pore channels of the micro-clamp.

[0011] Furthermore, the micro gripper includes:

[0012] The shell forms the lateral outer wall structure;

[0013] Pressure-bearing glass covers the top and bottom of the housing, forming the outer wall structure on the upper and lower sides, and together with the housing, forming a sealed cavity;

[0014] Pressure caps are located above and below the pressure-bearing glass;

[0015] An etching model is placed in the sealed cavity, on which multiple regular cylinders are engraved to simulate the pore channel structure with different throat sizes.

[0016] Furthermore, the housing has the following openings:

[0017] Connecting screws are used to secure the pressure cap, pressure-bearing glass, and housing;

[0018] The lead-out connector is connected to the outlet of the piston container or pressure regulating valve;

[0019] The inlet and outlet sealing rings are located at the outlet of the lead-out connector.

[0020] Furthermore, a sealing ring is provided between the pressure-bearing glass and the shell;

[0021] The micro gripper also includes a window sealing unit, a sample pressure pad, and a rubber plate;

[0022] The upper and lower viewing window sealing units are respectively located on the upper and lower sample pressure pads and rubber plates above and below.

[0023] Furthermore, the hydrogen generator employs a highly sensitive fuzzy logic system and an automatic tracking system, and is equipped with a reflux device to ensure that the instrument does not experience liquid backflow.

[0024] Furthermore, the pressure regulating valve is a high-pressure type pressure regulating valve, and its valve module is detachable and has a standard vent.

[0025] Furthermore, the first gas flow meter and the second gas flow meter are automatically switched between different flow ranges using a pneumatic valve via a computer, and a manual valve is also installed for manual switching. The flow meters can display instantaneous flow rate and cumulative flow rate.

[0026] Furthermore, the injection pump is a dual-cylinder constant-speed and constant-pressure pump, which is a horizontal flow pump, and uses a dual-plunger reciprocating type for fluid delivery.

[0027] Furthermore, the piston container adopts a ring-type combined sealing structure to eliminate the "pulse" phenomenon during low-speed pressure operation; the ring pressure tracking pump has manual and automatic functions to ensure that the ring pressure and internal pressure maintain a fixed difference.

[0028] The back pressure valve is a high-precision back pressure valve with a thin-plate structure, mainly composed of a stainless steel sheet, valve needle, valve seat, upper and lower valve bodies, and sealing ring.

[0029] The stereomicroscope and computer together constitute a high-definition image acquisition device, which can combine "microscopic simulation technology" and "image analysis" for the quantitative analysis of dynamic images of microscopic simulation displacement experiments.

[0030] This invention also provides a microscopic visualization method for two-phase flow displacement experiments in subsurface reservoirs, comprising the following steps:

[0031] S1: Install the micro-percolation chip on the micro-gripper and connect the injection module, pressure and temperature acquisition and control module, gas metering module, and data and image acquisition module to the micro-gripper;

[0032] S2: Clean the micro-permeation chip, open the corresponding valve, first turn on the vacuum pump to remove air and other impurities from the entire device, then fill the piston container with deionized water, and use the injection pump to inject the filled deionized water into the micro-permeation chip to fill the chip with deionized water. Finally, use the pressure regulating valve to continuously inject N2 into the micro model to dry the model.

[0033] S3: Contact angle measurements were performed to verify the hydrophilicity of the micromodel under experimental conditions. In this study, the drainage process was conducted at 25°C and ambient pressure. The H2 injection rate ranged from 0.005 ml / min to 0.1 ml / min, and the corresponding volumetric velocity was calculated.

[0034] S4: The stained saline solution is injected into the micro-permeation chip at a certain injection rate to remove N2 and completely saturate the pores; during this process, a stereomicroscope is used to observe whether saturation has been achieved; when there are no air bubbles in the entire pore region of the micro-model, it is considered that saturation has been achieved; then, a constant flow rate is set, and H2 is injected into the saline-saturated micro-model using a pressure regulating valve and a first gas flow meter. Once the hydrogen phase reaches the field of view, images of the saline phase are continuously recorded until no saturation occurs in the entire micro-model. When the quasi-stable condition is reached, a series of photographs are taken by slowly moving the stereomicroscope stage to compile the entire network.

[0035] S5: Use image processing software to quantify the residual brine saturation, separate the colors, and retain the red channel; obtain the percentage of residual brine by calculating the black or white pixels in the binary image; determine the saturation of the H2 phase based on the total area and pore area of ​​the micro-model.

[0036] S6: Repeat the experiment with chips of different porosities and pore sizes, record the data, and make comparisons.

[0037] The high-resolution image acquisition device, composed of the stereomicroscope and a computer, is used to observe and record the flow state of single-phase flow and gas-liquid two-phase flow in the pore network at the micrometer scale.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] (1) This invention utilizes a micro-gripper, a micro-flow chip, and a data and image acquisition module to solve the problem that traditional underground reservoir two-phase flow displacement experiments can only be conducted through numerical simulation or macroscopic experiments. It realizes microscopic visualization of the underground reservoir two-phase flow displacement process, making the experimental process intuitive and visible, and enabling observation of the entire flow process of brine and hydrogen two-phase displacement under different conditions.

[0040] (2) By fabricating a micro-permeation chip and extracting the micro-structural characteristics of real rocks using electron microscopy and X-ray microcomputed tomography images, this invention can accurately characterize pore space and extract statistical information, establishing quantitative relationships between parameters such as porosity, pore size, particle size distribution and anisotropy, providing a theoretical basis for studying hydrogen storage capacity and pore network structural characteristics.

[0041] (3) The injection module, pressure and temperature acquisition and control module and gas metering module provided by the present invention have high precision and stability, and can accurately control and monitor parameters such as pressure, temperature and flow rate in real time during the experiment, so as to ensure the accuracy of experimental data.

[0042] (4) The data and image acquisition system used in this invention can collect data such as pressure and flow rate in real time during the experiment, and combine with image processing software to analyze and process the experimental images, so as to realize the quantitative analysis of the two-phase flow displacement process and provide a theoretical reference for establishing hydrogen storage efficiency and prediction model under complex reservoir conditions. Attached Figure Description

[0043] Figure 1 A schematic diagram of the structure of a microscopically visualized two-phase flow displacement experimental system for underground reservoirs;

[0044] Figure 2 A schematic diagram of the micro-gripper structure for a microscopic visualization experimental system of two-phase flow displacement in underground reservoirs.

[0045] Reference numerals: 1. N2 gas cylinder; 2. Hydrogen generator; 3. Pressure regulating valve; 4-1. First gas flow meter; 4-2. Second gas flow meter; 5. Check valve; 6. Dual-cylinder constant speed and constant pressure pump; 7. Piston container; 8. Microscopic clamp; 9. Ring pressure tracking pump; 10. Vacuum pump; 11. Back pressure pump; 12. Desiccant; 13. Back pressure valve; 14. Gas-liquid separator; 15. Back pressure container; 16. Stereo microscope; 17. Computer; 18. Lead-out connector; 19. Semi-open insulation jacket; 20. Heating jacket; 21. Connecting screw; 22. Sealing ring; 23. Pressure cap; 24. Viewing window sealing unit; 25. Pressure-bearing glass; 26. Sample pressure pad and rubber plate; 27. Shell; 28. Inlet and outlet sealing rings. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0047] Example 1

[0048] This embodiment provides a microscopic visualization experimental system for two-phase flow displacement in underground reservoirs, such as... Figure 1 , 2 As shown, it includes: a micro-percolation chip and an injection module, a micro-gripper 8, a pressure and temperature acquisition and control module, a gas metering module, and a data and image acquisition module connected in sequence.

[0049] The micro-permeation chip is held in the micro-clamp 8;

[0050] The injection module includes an N2 gas cylinder 1, a hydrogen generator 2, a piston container 7, an injection pump, and a pressure regulating valve 3. The N2 gas cylinder 1 and the hydrogen generator 2 are both connected to the pressure regulating valve 3. The piston container 7 can hold two different liquids. The piston container 7 is connected to the injection pump to inject the two different liquids into the micro-percolation chip respectively. A first gas flow meter 4-1 and a one-way valve 5 are installed between the pressure regulating valve 3 and the piston container 7.

[0051] The pressure and temperature acquisition and control module includes: a ring pressure tracking pump 9, a back pressure unit, a temperature sensor, and a heating unit. The back pressure unit includes: a back pressure valve 13, a back pressure container 15, and a back pressure pump 11. The vacuum pump 10, the back pressure valve 13, the back pressure container 15, and the back pressure pump 11 are connected in sequence through pipelines. Pressure sensors and valves are installed between each pair of the vacuum pump 10, the back pressure valve 13, the back pressure container 15, and the back pressure pump 11. The heating device includes a semi-open insulation jacket 19 and an electric heating jacket 20. The semi-open insulation jacket 19 and the electric heating jacket 20 are built into the micro clamp 8.

[0052] The gas metering module includes a flow meter group consisting of a second gas flow meter 4-2, a desiccant 12, and a gas-liquid separator 14 connected in sequence.

[0053] The data and image acquisition module includes: pressure sensors at multiple points on the pipeline, digital display instruments, data acquisition cards, oil displacement light sources, stereo microscopes 16 and computers 17, with the lens of the stereo microscope 16 aligned with the pore channel of the micro-clamping device 8.

[0054] In a specific embodiment, the micro gripper 8 includes:

[0055] Shell 27 forms the lateral outer wall structure;

[0056] Pressure-bearing glass 25 covers the top and bottom of the housing 27, forming the outer wall structure on the upper and lower sides, and together with the housing 27, forms a sealed cavity;

[0057] Pressure cap 23 is located above and below pressure-bearing glass 25;

[0058] An etching model is placed in the sealed cavity, on which multiple regular cylinders are engraved to simulate the pore channel structure with different throat sizes.

[0059] In a specific embodiment, the housing 27 has the following openings:

[0060] Connecting screw 21 is used to fix the pressure cap 23, the pressure-bearing glass 25 and the housing 27;

[0061] Lead-out connector 18 is connected to the outlet of the piston container 7 or the pressure regulating valve 3;

[0062] The inlet and outlet sealing ring 28 is located at the outlet of the lead-out connector 18.

[0063] In a specific embodiment, a sealing ring 22 is provided between the pressure-bearing glass 25 and the housing 27;

[0064] The micro gripper 8 also includes a window sealing unit 24 and a sample pressure pad and rubber plate 26;

[0065] The upper and lower viewing window sealing units 24 are respectively located above and below the upper and lower sample pressure pads and rubber plate 26.

[0066] In a specific implementation, the hydrogen generator 2 adopts a highly sensitive fuzzy system and an automatic tracking system, and is equipped with a reflux device to ensure that the instrument does not experience liquid backflow.

[0067] In a specific implementation, the pressure regulating valve 3 is a high-pressure type pressure regulating valve, whose valve module is detachable and has a standard vent.

[0068] In a specific implementation, the first gas flow meter 4-1 and the second gas flow meter 4-2 are automatically switched between different ranges using a pneumatic valve via a computer. At the same time, a manual valve is installed to enable manual switching, and the instantaneous flow rate and cumulative flow rate can be displayed.

[0069] In a specific implementation, the injection pump is a dual-cylinder constant speed and constant pressure pump 6, which is a horizontal flow pump, and uses a dual-plunger reciprocating type for infusion.

[0070] In a specific embodiment, the piston container 7 adopts a ring-type combined sealing structure to eliminate the "pulse" phenomenon during low-speed pressure operation; the ring pressure tracking pump 9 has manual and automatic functions to ensure that the ring pressure and internal pressure maintain a fixed difference.

[0071] The back pressure valve 13 is a high-precision back pressure valve with a thin-plate structure, mainly composed of a stainless steel sheet, valve needle, valve seat, upper and lower valve bodies, and sealing ring.

[0072] The stereomicroscope 16 and computer 17 together constitute a high-definition image acquisition device, which can combine "microscopic simulation technology" and "image analysis" for quantitative analysis of dynamic images of microscopic simulation displacement experiments.

[0073] This embodiment also provides a microscopic visualization method for two-phase flow displacement experiments in subsurface reservoirs, including the following steps:

[0074] S1: Fabrication of a micro-flow chip: Electron microscopy and X-ray computed tomography images are used to extract the microstructural characteristics of real rocks and characterize their pore space. Statistical information is then extracted, including porosity, pore size distribution, and anisotropy. Next, the QSGS algorithm is used to generate an equivalent geometry. The statistical information of the generated porous medium is analyzed to determine if it sufficiently approximates a real porous medium. When all statistical information closely approximates a real porous medium, a file suitable for the printing system is output, thus producing the micro-flow chip. The micro-flow chip is then mounted on a micro-gripper 8, and the injection module, pressure and temperature acquisition and control module, gas metering module, and data and image acquisition module are connected to the micro-gripper.

[0075] S2: Clean the micro-permeation chip, open the corresponding valve, first turn on the vacuum pump 10 to remove air and other impurities in the entire device, then fill the piston container 7 with deionized water, use the injection pump to inject the filled deionized water into the micro-permeation chip, so that the chip is filled with deionized water, and finally use the pressure regulating valve 3 to continuously inject N2 into the micro model to dry the model.

[0076] S3: Contact angle measurements were performed to verify the hydrophilicity of the micromodel under experimental conditions. In this study, the drainage process was conducted at 25°C and ambient pressure. The H2 injection rate ranged from 0.005 ml / min to 0.1 ml / min, and the corresponding volumetric velocity was calculated.

[0077] S4: The stained saline solution is injected into the micro-permeation chip at a certain injection rate to remove N2 and completely saturate the pores; during this process, the stereomicroscope 16 is used to observe whether saturation has been achieved; when there are no bubbles in the entire pore region of the micro-model, it is considered that saturation has been achieved; then, a constant flow rate is set, and H2 is injected into the saline-saturated micro-model using the pressure regulating valve 3 and the first gas flow meter 4-1. Once the hydrogen phase reaches the field of view, the image of the saline phase is continuously recorded until no saturation occurs in the entire micro-model. When the quasi-stable condition is reached, a series of photographs are taken by slowly moving the stage of the stereomicroscope 16 to edit the entire network;

[0078] S5: Use image processing software to quantify the residual brine saturation, separate the colors, and retain the red channel; obtain the percentage of residual brine by calculating the black or white pixels in the binary image; determine the saturation of the H2 phase based on the total area and pore area of ​​the micro-model.

[0079] S6: Repeat the experiment with chips of different porosities and pore sizes, record the data, and make comparisons.

[0080] The high-resolution image acquisition device, which is composed of the stereomicroscope 16 and the computer 17, is used to observe and record the flow state of single-phase flow and gas-liquid two-phase flow in the pore network at the micrometer scale.

[0081] This embodiment simulates the two-phase flow displacement process of underground reservoirs under different pore structures or environmental conditions. Different types of gases are injected sequentially into a micro-flow chip, followed by the injection of displacement fluids such as water and chemicals. Using a high-magnification microscope and a visual model, the flow of oil and water within the model and the distribution of residual oil after oil-water flooding, water-oil flooding, polymer flooding, and other chemical flooding processes can be directly observed. Simultaneously, a microscope with a sampling port captures the flow of fluid at each step of the displacement process in real time, quantitatively describing the distribution and magnitude of oil-water saturation during the displacement process in the micro-pore structure. This provides a theoretical reference for studying the quantitative relationship between hydrogen storage capacity and pore network structure characteristic parameters and multiphase flow field parameters, and for establishing hydrogen storage efficiency and prediction models under complex reservoir conditions.

[0082] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0083] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A microscopic visualization experimental system for two-phase flow displacement in underground reservoirs, characterized in that, include: The micro-percolation chip is connected in sequence with an injection module, a micro-clamp (8), a pressure and temperature acquisition and control module, a gas metering module, and a data and image acquisition module; The micro-permeation chip is held in the micro-clamp (8); The injection module includes an N2 gas cylinder (1), a hydrogen generator (2), a piston container (7), an injection pump, and a pressure regulating valve (3). The N2 gas cylinder (1) and the hydrogen generator (2) are both connected to the pressure regulating valve (3). The piston container (7) can hold two different liquids. The piston container (7) is connected to the injection pump to inject the two different liquids into the micro-percolation chip respectively. A first gas flow meter (4-1) and a one-way valve (5) are installed between the pressure regulating valve (3) and the piston container (7). The pressure and temperature acquisition and control module includes: a ring pressure tracking pump (9), a back pressure unit, a temperature sensor and a heating unit. The back pressure unit includes: a back pressure valve (13), a back pressure container (15) and a back pressure pump (11). The vacuum pump (10), the back pressure valve (13), the back pressure container (15) and the back pressure pump (11) are connected in sequence through pipelines. Pressure sensors and valves are installed between each pair of the vacuum pump (10), the back pressure valve (13), the back pressure container (15) and the back pressure pump (11). The gas metering module includes a flow meter group consisting of a second gas flow meter (4-2), a desiccant (12), and a gas-liquid separator (14) connected in sequence. The data and image acquisition module includes: pressure sensors, digital display instruments, data acquisition cards, oil displacement light sources, stereo microscopes (16) and computers (17) located at multiple points on the pipeline. The lens of the stereo microscope (16) is aligned with the pore channel of the micro-clamp (8). The experimental method for a microscopic visualization experimental system for two-phase flow displacement in subsurface reservoirs includes the following steps: S1: Install the micro-percolation chip on the micro-gripper (8), and connect the injection module, pressure and temperature acquisition and control module, gas metering module, data and image acquisition module to the micro-gripper; S2: Clean the micro-percolation chip, open the corresponding valve, first turn on the vacuum pump (10) to remove impurities in the whole device, then fill the piston container (7) with deionized water, use the injection pump to inject the filled deionized water into the micro-percolation chip, so that the chip is filled with deionized water, and finally use the pressure regulating valve (3) to continuously inject N2 into the micro model to dry the model. S3: Perform contact angle measurements to verify whether the micro-model is hydrophilic under experimental conditions; S4: The dyed saline solution is injected into the micro-permeation chip at a certain injection rate to remove N2 and completely saturate the pores; during this process, a stereomicroscope (16) is used to observe whether saturation has been achieved; when there are no bubbles in the entire pore area of ​​the micro-model, it is considered that saturation has been achieved; then, a constant flow rate is set, and H2 is injected into the saline-saturated micro-model using a pressure regulating valve (3) and a first gas flow meter (4-1). Once the hydrogen phase reaches the field of view, the image of the saline phase is continuously recorded until no saturation occurs in the entire micro-model. When the quasi-stable condition is reached, a series of photographs are taken by slowly moving the stage of the stereomicroscope (16) to edit the entire network. S5: Use image processing software to quantify the residual brine saturation, separate the colors, and retain the red channel; obtain the percentage of residual brine by calculating the black or white pixels in the binary image; determine the saturation of the H2 phase based on the total area and pore area of ​​the micro-model. S6: Repeat the experiment with chips of different porosities and pore sizes, record the data, and make comparisons.

2. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The micro gripper (8) includes: The shell (27) forms a lateral outer wall structure; Pressure-bearing glass (25) covers the top and bottom of the housing (27) to form the outer wall structure on the upper and lower sides, and together with the housing (27) forms a sealed cavity; A pressure cap (23) is provided above and below the pressure-bearing glass (25); An etching model is placed in the sealed cavity, on which multiple regular cylinders are engraved to simulate the pore channel structure with different throat sizes.

3. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 2, characterized in that, The housing (27) has the following openings: Connecting screws (21) are used to fix the pressure cap (23), the pressure glass (25) and the housing (27); Lead-out connector (18) is connected to the outlet of the piston container (7) or pressure regulating valve (3); The inlet and outlet sealing ring (28) is located at the outlet of the lead-out connector (18).

4. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 2, characterized in that, A sealing ring (22) is provided between the pressure-bearing glass (25) and the shell (27); The micro gripper (8) also includes a window sealing unit (24) and a sample pressure pad and rubber plate (26). The upper and lower window sealing units (24) are respectively located above and below the upper and lower sample pressure pads and rubber plates (26).

5. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The hydrogen generator (2) adopts a highly sensitive fuzzy system and an automatic tracking system, and is equipped with a reflux device to ensure that the instrument does not have a liquid return phenomenon.

6. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The pressure regulating valve (3) is a high-pressure type pressure regulating valve. Its valve module is detachable and has a standard vent.

7. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The first gas flow meter (4-1) and the second gas flow meter (4-2) are automatically switched between different ranges by a pneumatic valve via a computer. At the same time, a manual valve is installed to enable manual switching. They can display instantaneous flow and cumulative flow.

8. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The injection pump is a dual-cylinder constant speed and constant pressure pump (6), which is a horizontal flow pump and uses a double plunger reciprocating type for infusion.

9. The microscopic visualization experimental system for two-phase flow displacement of underground reservoirs according to claim 1, characterized in that, The piston container (7) adopts a ring-type combined sealing structure to eliminate the "pulse" phenomenon when running at low speed and pressure; the ring pressure tracking pump (9) has manual and automatic functions to ensure that the ring pressure and internal pressure maintain a fixed difference.

Images