A multiphase displacement test system considering gravity effect

Abstract

The utility model discloses a kind of multi-phase displacement test system considering gravity influence, it is related to test equipment technical field. Including support, the side vertical surface parallel of support is rotationally connected disc, track is equipped on the surface of disc, track is set along the diameter of disc, track is slidably connected electron microscope, test table, plane light source in turn, microfluidic chip and annular lamp are all installed on test table, injection pump is communicated with the injection inlet of microfluidic chip by microfluidic pipeline, the outlet of microfluidic chip is communicated with collecting bottle by microfluidic pipeline. The present application introduces gravity influence, to in-depth understanding of the migration and displacement law of multiphase fluid in complex porous media, and further provides reliable theoretical basis and technical support for the field of environmental protection, energy development and geological engineering, has important scientific significance and application value.

Description

Technical Field

[0001] This utility model belongs to the field of experimental equipment technology, and more specifically, it relates to a multiphase displacement test system that takes into account the influence of gravity. Background Technology

[0002] Multiphase fluid displacement in porous media is widespread in various research and application fields such as environmental science, petroleum engineering, and geology. It is a typical scientific problem in engineering practices such as groundwater pollution remediation, oil and gas extraction efficiency enhancement, and carbon dioxide geological sequestration. In these scenarios, crude oil, pollutants, or other target fluids often remain trapped in porous media with extremely small pore sizes and complex morphologies. Injecting displacing fluids into the media, allowing them to interact with the displaced fluids and form two-phase or multiphase flows, is a key means to achieve pollutant migration control or enhance oil recovery.

[0003] However, the internal structure of porous media is highly complex and heterogeneous. Pore spaces vary significantly in scale, morphology, and connectivity, and the surface roughness, wettability, and mineral composition of the pore walls also significantly influence fluid behavior. Differences in the fluid's viscosity, density, and interfacial tension, coupled with environmental factors such as temperature, pressure, and gravity, result in highly nonlinear and unpredictable transport patterns of multiphase fluids in porous media. Traditional multiphase flow theory based on Darcy's law offers some macroscopic guidance but struggles to reveal the dynamic evolution of multiphase interfaces at the microscopic pore scale. While numerical simulations based on the Navier-Stokes equations can describe mesoscopic mechanisms, their computational complexity is extremely high due to the equations' high nonlinearity, and even with high-performance numerical solvers, problems such as massive computational demands and insufficient interface capture accuracy persist.

[0004] One of the key reasons for this challenge is that current experimental studies on multiphase displacement phenomena primarily focus on natural rock cores or soil masses. These materials are inherently opaque and uncontrollable, making it impossible to directly, continuously, and at high resolution observe the transport process of multiphase fluids during experiments. Instead, inferences can only be made based on macroscopic outputs or indirect signals, making it difficult to fully reveal their mechanisms of action and evolutionary patterns.

[0005] Therefore, to study the displacement behavior of multiphase fluids in porous media, it is necessary to develop more intuitive, controllable and repeatable experimental methods to make up for the shortcomings of traditional methods. Utility Model Content

[0006] The technical problem to be solved by this invention is to provide a multiphase displacement test system that considers the influence of gravity. It utilizes transparent materials to construct a representative porous medium model, combines high-resolution observation technology to record the fluid transport process in real time, simulates different porosities, permeabilities and heterogeneous characteristics through structural design, and introduces the influence of gravity into the test system. This has important scientific significance and application value for a deeper understanding of the transport and displacement laws of multiphase fluids in complex porous media, and provides a reliable theoretical basis and technical support for fields such as environmental protection, energy development and geological engineering.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a multiphase displacement test system considering the influence of gravity, including a support, the side of the support being parallel to and rotatably connected to a disk, a track being provided on the surface of the disk, the track being arranged along the diameter of the disk, and the track being sequentially slidably connected to an electron microscope, a test platform, and a planar light source, a microfluidic chip and a ring lamp being mounted on the test platform, an injection pump being connected to the injection port of the microfluidic chip through a microfluidic pipeline, and the outlet port of the microfluidic chip being connected to a collection bottle through a microfluidic pipeline.

[0008] Preferably, the microfluidic chip uses a transparent glass substrate as the main material, and the surface has a porous network structure.

[0009] Preferably, the pore network structure is composed of interconnected polygonal micropore structures, and the pore shape is square, hexagonal or other irregular shape.

[0010] Preferably, the microfluidic chip is a single-layer chip structure or a multi-layer chip structure. The multi-layer chip is formed by bonding at least two substrates with different pore network structures together.

[0011] Preferably, the pore network structure of the single-layer chip structure is unfolded on a single plane, and the overall pore distribution is uniform; the pore network structure of each layer in the multi-layer chip structure has different pore size distribution, different geometric shape or different permeation characteristics, or is a multi-level pore size gradually changing stacked structure.

[0012] Preferably, both the outlet and injection port of the microfluidic chip are sealed with polydimethylsiloxane.

[0013] The beneficial effects of adopting the above technical solution are as follows:

[0014] 1. By rotating a disk at different angles, the flow behavior of fluids within a microfluidic chip can be observed and analyzed, and the influence of gravity or its components on the flow characteristics of multiphase fluids can be examined. Gravity plays a crucial role in practical applications, especially in inclined geological structures or non-horizontal reservoirs, where fluid movement is significantly affected. By setting different angles for the disk in experiments, actual working conditions can be more realistically reflected, revealing in depth the mechanism and extent of gravity's influence on fluid flow. This is of great significance for understanding the flow laws of fluids in real environments, providing important experimental data and theoretical support for the design, optimization, and implementation of environmental geotechnical engineering and reservoir engineering. This not only helps scientists and engineers gain a more comprehensive understanding of the flow characteristics of multiphase fluids but also provides more scientific and accurate basis and technical support for practical engineering applications.

[0015] 2. A rotating support bracket is used to connect the disc. A track is installed on the disc, and the electron microscope, test platform, and planar light source are slidably connected to the track. This allows for flexible adjustment of the spacing and position of each test component on the track, and also enables the entire system to be tilted at multiple angles by manually rotating the disc. This allows the microfluidic chip and test platform to be tilted at different angles during the test, effectively simulating tilted structures or non-horizontal reservoir conditions in actual geological environments, and more realistically reproducing the flow and displacement laws of fluids in porous media.

[0016] 3. The microfluidic chip uses a transparent glass substrate as its main material. The glass substrate not only possesses excellent transparency but also exhibits corrosion resistance and mechanical stability, enabling it to withstand multiple injection and discharge processes of the displacing fluid without deformation or damage, thus ensuring the stability and repeatability of the experimental results. Both the injection and outlet ports of the microfluidic chip are sealed with polydimethylsiloxane (PDMS). This material is highly flexible and has good hydrophilicity, ensuring the airtightness of fluid transport during the experiment and facilitating reliable connection with external pipelines, thereby improving the controllability and flexibility of the experimental operation.

[0017] 4. The pore network of a microfluidic chip consists of a series of interconnected polygonal micropores. The pore size and geometry can be designed and controlled according to experimental requirements. The pore shape can be square, hexagonal, or other irregular shapes to closely resemble the pore characteristics of natural rocks or soils. By rationally designing the pore size, shape, and connectivity, porous media structures with different porosities, permeabilities, and degrees of heterogeneity can be simulated, providing a controllable experimental platform for studying the migration behavior of fluids in different types of reservoirs or soil media.

[0018] 5. Microfluidic chips can be single-layer or multi-layer structures. In a single-layer chip, the pore network unfolds on a single plane, resulting in a uniform overall pore distribution, capable of simulating an idealized homogeneous porous media environment. These chips are suitable for conducting conventional multiphase displacement experiments such as water-driven and gas-driven oil recovery, facilitating the analysis of fluid transport patterns, displacement front advancement characteristics, and displacement efficiency under homogeneous media conditions. Multi-layer chip structures can simulate more complex heterogeneous formation conditions, reproducing the preferential flow paths, breakthrough channels, and residual saturation distribution of fluids in heterogeneous media, more closely approximating the complex conditions in actual oil reservoirs and soil masses. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the test system;

[0020] Figure 2 This is a schematic diagram of the main structure of the disk;

[0021] Figure 3 This is a schematic diagram of a single-layer chip structure.

[0022] Figure 4 This is a schematic diagram of a multi-layer chip structure;

[0023] In the diagram: 1. Support, 2. Disk, 3. Planar light source, 4. Collection bottle, 5. Experimental stage, 6. Microfluidic chip, 7. Ring lamp, 8. Electron microscope, 9. Syringe pump, 10. Track. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] like Figure 1-2 As shown, the multiphase displacement experimental system includes a support 1, a disc 2, a planar light source 3, a collection bottle 4, an experimental platform 5, a microfluidic chip 6, a ring lamp 7, an electron microscope 8, a syringe pump 9, and a track 10. The support 1 is the main supporting part of the entire system, on which a rotating disc 2 is fixed. The rotating disc 2 can rotate around its central axis, used to adjust the overall angle of each component on the disc 2, thereby realizing the consideration and simulation of gravity or its components.

[0026] A track 10 is provided on the disk 2, and the track 10 is set along the diameter of the disk 2. The electron microscope 8, the test stage 5, and the planar light source 3 are sequentially mounted on the track 10 and can slide along the track 10 to adjust the relative distance between the three to optimize the image clarity and illumination effect. The microfluidic chip 6 and the ring lamp 7 are both mounted on the test stage 5. Among them, the electron microscope 8 is a high-definition industrial electron microscope. The syringe pump 9 is connected to the injection port of the microfluidic chip 6 through a microfluidic pipeline, and the outlet port of the microfluidic chip 6 is connected to the collection bottle 4 through a microfluidic pipeline. The syringe pump 9 is a thermostatic and constant-pressure syringe pump, used to precisely control the flow rate of fluid entering the microfluidic chip 6 to ensure that the fluid passes through the microchannel at a stable rate during the experiment. The collection bottle 4 collects the fluid discharged by the system. The disk 2 can not only rotate around its own center to realize the displacement experiment of the microfluidic chip 6 at different angles, but also adjust the distance between the electron microscope 8, the microfluidic chip 6, and the planar light source 3 up and down through the track 10, thereby ensuring clear imaging and ensuring the best effect for shooting and recording. Electron microscope 8 records the fluid transport process in microfluidic chip 6 in real time, clearly showing the flow behavior and interaction mechanism of fluid in porous media.

[0027] To further improve imaging quality, when the microfluidic chip 6 has a large thickness or small internal pores, a ring lamp 7 can be added as a supplementary lighting device to the planar light source 3. The ring lamp 7 provides uniform and soft multi-angle illumination, effectively eliminating shadows caused by chip thickness or structure, reducing reflections and glare, thereby significantly enhancing image contrast and clarity, and allowing for a more intuitive presentation of the fine pore structure and fluid dynamics. This lighting design is particularly important for experiments requiring high-precision imaging, providing reliable data support for revealing the displacement mechanism of multiphase fluids in porous media.

[0028] The microfluidic chip 6 uses a transparent glass substrate as the main material, with a porous network structure on its surface. This porous network structure consists of interconnected polygonal micropores, with pore shapes that are square, hexagonal, or other irregular forms. For example... Figure 3-4As shown, the microfluidic chip 6 has a single-layer or multi-layer chip structure. A multi-layer chip is formed by bonding at least two substrates with different pore network structures together. The pore network structure of a single-layer chip unfolds on a single plane, with a uniform overall pore distribution, making it suitable for conducting conventional multiphase displacement experiments such as water-driven and gas-driven oil displacement. This facilitates the analysis of fluid transport patterns, displacement front advancement characteristics, and displacement efficiency under homogeneous media conditions. In a multi-layer chip structure, each layer has a different pore size distribution, different geometry, or different permeability characteristics to simulate more complex heterogeneous reservoir conditions. For example, a "high-permeability layer—low-permeability layer" superimposed system can be constructed, or a multi-level pore size gradually changing stacked structure can be designed to reproduce the preferential flow path, breakthrough channels, and residual saturation distribution of fluids in heterogeneous media, more closely resembling the complex conditions in actual oil reservoirs and soil masses. Furthermore, because the microfluidic chip 6 is entirely transparent, it can be used in conjunction with an electron microscope 8 and a planar light source 3 during experiments to achieve real-time and intuitive observation of the multiphase fluid transport process. During the experiment, dyes or fluorescent tracers can be added to the injected fluid to create distinct color or brightness contrasts between different fluids under a microscope, thus clearly revealing the distribution pattern and interface evolution of the fluids. Compared with traditional core physics experiments, this chip not only has advantages such as low processing cost, strong controllability of structural parameters, and good reusability, but also significantly improves the visualization and precision of the experiment, greatly enhancing the flexibility and scientific rigor of the experimental research.

[0029] The microfluidic chip 6 has injection and outlet ports on both sides for fluid injection and extraction, respectively. These designs are crucial for fluid manipulation during experiments. However, due to the high rigidity of the glass chip material, directly connecting the metal injection needles at both ends of the microfluidic tubing to the microfluidic chip 6 often results in an unsatisfactory seal. This connection method, under the action of the syringe pump 9, easily leads to fluid leakage at the connection point. Fluid leakage not only affects the accuracy of experimental results but may also damage the experimental equipment. To avoid this and ensure the accuracy of the experiment and the airtightness of the fluid system, polydimethylsiloxane (PDMS) is used to seal the injection and outlet ports. PDMS is a flexible material with good elasticity and sealing properties, effectively compensating for the rigidity difference between the glass chip and the metal injection needles. These sealing points are connected to the syringe pump 9 and the collection bottle 4 via the microfluidic tubing. The syringe pump 9 is used to precisely regulate the fluid rate entering the microfluidic chip 6, ensuring the experiment can proceed according to predetermined parameters. The collection bottle 4 is used to collect and treat any leaked fluid that may occur during the experiment, further improving the safety and reliability of the system. This design allows fluid to smoothly enter the microfluidic chip 6 at a set rate and be effectively discharged, maintaining a high degree of sealing and operational precision throughout the system. This not only improves the reliability of experimental data but also extends the lifespan of the equipment, ensuring the smooth conduct of experiments and the repeatability of results.

[0030] The microfluidic chip 6 is a crucial component of this system, fabricated using an etching process. Based on the designed microfluidic channel planar pattern, microfluidic channels are etched to simulate the pores between real rock or soil particles. These microfluidic channels precisely reproduce the internal structure of the rock or soil, allowing for detailed studies of fluid flow within it. For different fluids (such as water and oil), targeted chemical modifications or coatings are required on the chip. These treatments can adjust the chip surface's affinity for fluids, for example, by increasing hydrophilicity or oleophilicity, to more accurately simulate the response of real rock or soil to fluids.

[0031] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A multiphase displacement test system considering the influence of gravity, characterized in that, The device includes a support (1), the side of which is parallel to and rotatably connected to a disk (2). A track (10) is provided on the surface of the disk (2), the track (10) is set along the diameter of the disk (2), and the track (10) is slidably connected to an electron microscope (8), a test platform (5), and a plane light source (3) in sequence. The microfluidic chip (6) and the ring lamp (7) are both installed on the test platform (5). The injection pump (9) is connected to the injection port of the microfluidic chip (6) through a microfluidic pipeline, and the outlet of the microfluidic chip (6) is connected to the collection bottle (4) through a microfluidic pipeline.

2. The multiphase displacement test system considering the influence of gravity according to claim 1, characterized in that, The microfluidic chip (6) uses a transparent glass substrate as the main material and has a porous network structure on its surface.

3. The multiphase displacement test system considering the influence of gravity according to claim 2, characterized in that, The pore network structure is composed of interconnected polygonal micropore structures, with pore shapes that are square, hexagonal, or irregular.

4. The multiphase displacement test system considering the influence of gravity according to claim 2, characterized in that, The microfluidic chip (6) has a single-layer chip structure or a multi-layer chip structure. The multi-layer chip is formed by bonding at least two substrates with different pore network structures together.

5. A multiphase displacement test system considering the influence of gravity according to claim 4, characterized in that, In a single-layer chip structure, the pore network structure unfolds on a single plane, and the overall pore distribution is uniform. In a multi-layer chip structure, the pore network structure of each layer has different pore size distribution, different geometric shape or different permeation characteristics, or it is a multi-level pore size gradually changing stacked structure.

6. The multiphase displacement test system considering the influence of gravity according to claim 1, characterized in that, The outlet and injection port of the microfluidic chip (6) are sealed with polydimethylsiloxane.

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