Non-continuous phase seepage experiment device of gel-containing particles and critical pressure determination method

Abstract

The present application relates to a non-continuous phase seepage experiment device containing gel particles and a critical pressure determination method, comprising a micro-liquid injection system, a pressure collection and transmission system, a microscopic observation system, a particle screening and migration system in a micro-channel; by building a non-continuous phase seepage experiment device, the particle size of the gel particles is accurately screened by using a customized microfluidic chip, the migration form, existing state and pressure fluctuation of the gel particles under different particle sizes, different elastic moduli and different quantities in the single-channel microfluidic chip are monitored in real time by using a high-precision pressure sensing system and a microscopic observation system. According to the variation law of the critical pressure of the gel particles passing through a single throat under different conditions, the migration variation characteristics of the gel particles in the pore throat can be quantitatively analyzed, a gel particle deformation and migration characterization model is established, which has important guiding significance for studying the seepage mechanism of the gel particles in the porous medium and the optimal matching relationship between the particle size and the pore throat size.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development engineering, in particular to a non-continuous phase seepage experiment device containing gel particles and a critical pressure determination method. BACKGROUND

[0002] After long-term water injection development or polymer flooding development, the reservoir heterogeneity is very serious. The non-homogeneous composite flooding containing gel particles is an effective method to further improve the oil recovery. The gel particles can temporarily block the high permeability channel, causing the liquid flow to divert from the high permeability area to the low permeability area to promote balanced displacement of the oil reservoir. After the gel particles block the high permeability channel, the local pressure gradually rises, and the deformed particles pass through the channel after reaching the critical passing pressure. The characteristics of the non-continuous phase seepage of blocking-deformation migration-reblocking can effectively displace the remaining crude oil in the reservoir formation. However, the current research on the micro seepage of gel particles mainly focuses on the migration form of gel particles in microchannels, and few quantitative analyses of the relationship between the critical passing pressure of gel particles and the throat radius under different elastic moduli, different concentrations, and different particle sizes are conducted. Therefore, a micro experimental device for non-continuous phase seepage containing gel particles and a critical pressure determination method are needed to quantitatively study the seepage mechanism of gel particles in microchannels under different conditions and to quantitatively analyze various factors, so as to provide input parameters and basic theoretical knowledge for macro seepage experiments and simulation. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a non-continuous phase seepage experiment device containing gel particles.

[0004] In order to analyze various factors, the present application needs to establish a microfluidic experimental device to monitor the pressure fluctuations generated by different types and quantities of gel particles in a single channel, establish a certain relationship between each factor and the pressure fluctuations, and obtain a critical passing pressure and a limiting ratio (the ratio of the gel particles to the throat radius) relationship chart of the gel particles passing through the throat under different elastic moduli and different quantities, and determine the limit of the gel particle rupture.

[0005] The present application also provides a method for determining the critical pressure by using the above-mentioned non-continuous phase seepage experiment device containing gel particles.

[0006] The technical scheme of the present application is as follows:

[0007] A non-continuous phase seepage experiment device containing gel particles, comprising a micro-liquid injection system, a pressure collection and transmission system, a microscopic observation system, a particle screening and migration system in a microchannel.

[0008] The micro-liquid injection system is used for injecting different types of gel particle solutions; the pressure acquisition and transmission system is used for monitoring pressure fluctuation characteristics of gel particles in the process of migration and plugging in the micro-channel; the microscopic observation system is used for visualizing research on migration state and plugging mode of the gel particles in the micro-channel; and the micro-channel particle screening and migration system is used for accurately screening target gel particles.

[0009] According to the application, the micro-liquid injection system comprises a micro-injection pump, a micro-injector and a pipeline.

[0010] The micro-injector is matched with the micro-injection pump, and the micro-injector is fixed on the micro-injection pump, so that the liquid in the micro-injector is pumped into the micro-channel particle screening and migration system through the pipeline by the micro-injection pump.

[0011] According to the application, the pressure acquisition and transmission system comprises a T-shaped pipeline connector, a pressure sensor, a controller, a communication module and a computer, and the T-shaped pipeline connector, the controller, the communication module and the computer are sequentially connected.

[0012] The T-shaped pipeline connector is connected to the pipeline, and when the fluid passes through the T-shaped pipeline connector, the internal pressure of the pipeline is sensed by the pressure sensor through the T-shaped pipeline connector, then data acquisition and control are performed by the controller, and finally data transmission is performed by the communication module and the computer.

[0013] According to the application, the microscopic observation system comprises a high-speed camera and a microscope.

[0014] The target gel particles are captured by the microscope, and then the plugging and migration mode of the target gel particles in the micro-channel are observed by the high-speed camera.

[0015] According to the application, the micro-channel particle migration system comprises single-channel microfluidic chips with different structures.

[0016] According to the application, the single-channel microfluidic chip comprises a gel particle injection port, a gel particle screening port, a waste liquid discharge port, an adjustable valve, a continuous phase injection port, a main migration micro-channel, an S-shaped channel, a convergent channel, a narrow throat and a gel particle discharge port.

[0017] The gel particle injection port and the waste liquid discharge port are located on the same straight line, the channel where the gel particle screening port is located is perpendicular to the communication channel of the gel particle injection port and the waste liquid discharge port; the main migration micro-channel and the communication channel of the gel particle injection port and the waste liquid discharge port form an angle of 125°-150°, the continuous phase injection port is vertically communicated with the main channel, and the main migration micro-channel, the S-shaped channel, the converging channel, the narrow throat and the gel particle discharge port are sequentially communicated.

[0018] The adjustable valve is located at the leftmost end of the main migration micro-channel, and controls the communication of the screening channel and the migration channel.

[0019] According to the application, the micro-injection pump comprises a constant flow micro-injection pump and a constant pressure micro-injection pump, which are respectively used for setting specific flow and specific injection pressure.

[0020] According to the application, the material of the pipeline is polytetrafluoroethylene, fluorinated ethylene propylene copolymer or Tygon silica gel, and the inner diameter of the pipeline is 0.039mm-2.54mm.

[0021] According to the application, the material of the single-channel micro-fluidic chip is polymethyl methacrylate (PMMA) or polydimethylsiloxane, and the thickness of the single-channel micro-fluidic chip is 0.5cm-1.5cm.

[0022] According to the application, the micro-liquid injection system further comprises a filter connected to the micro-injector, which is used for filtering large-particle impurities in the solution.

[0023] A method for determining the critical pressure by using the above-mentioned non-continuous phase seepage experiment device containing gel particles, comprising the following steps:

[0024] The pressure fluctuation generated by different types and quantities of gel particles in the single channel is monitored;

[0025] The relationship between the critical pressure generated when gel particles with different elastic moduli and different concentrations pass through the throat and the restriction ratio is established, and the limit of gel particle rupture is determined;

[0026] Considering the factors such as elastic modulus, gel particle radius and throat radius when the gel particles deform and pass through, a quantitative characterization model for the gel particles deforming and passing through the throat is established.

[0027] A method for determining the critical pressure by using the above-mentioned non-continuous phase seepage experiment device containing gel particles, comprising the following steps:

[0028] (1) through the third micro-injection pump, the continuous phase fluid in the micro-injector of screening gel particles is injected into the single-channel microfluidic chip through the gel particle screening port, the whole single-channel microfluidic chip is saturated with continuous phase fluid, and the adjustable valve is closed;

[0029] (2) through the first micro-injection pump, the spherical gel particles in the micro-injector of storing gel particles are injected through the gel particle injection port at an injection flow rate of 0.1-2 μl / min;

[0030] (3) when the target gel particles are observed, the adjustable valve is slowly opened, the target gel particles are quickly driven into the main migration microchannel by adjusting the flow rate of the third micro-injection pump, and the adjustable valve is closed, so that the target gel particles migrate along the main migration microchannel;

[0031] (4) through the second micro-injection pump, the injection displacement phase fluid in the micro-injector of injecting displacement phase fluid is injected through the continuous phase injection port at an injection flow rate of 0.1-10 μl / min, and the target gel particles are continuously pushed through the S-shaped channel to the converging channel;

[0032] (5) the high-speed camera and the microscope are used to collect the particle migration form in real time, the pressure sensor is used to monitor the pressure change of the spherical gel particles during the process of passing through the narrow throat, and the critical pressure is determined, the critical pressure is the maximum pressure at which the spherical gel particles can deform and pass through the narrow throat.

[0033] The beneficial effects of the present application are:

[0034] 1、the single-channel microfluidic chip designed in the present application can realize screening of target gel particles in the microchannel.

[0035] 2、the present application can obtain the critical passing pressure and the limiting ratio relationship diagram of the gel particles passing through the throat under different particle sizes through microfluidic experiments, and establish a quantitative characterization model for the deformation of the gel particles.

[0036] 3、the present application is carried out under visual conditions, the seepage form of the gel particles in the microchannel can be observed in real time, the chip used in the experiment can be repeatedly used, and the experimental cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 it is a schematic diagram of the non-continuous phase seepage experimental device of the present application containing gel particles;

[0038] Figure 2 it is a schematic diagram of the internal structure of the single-channel microfluidic chip of the present application;

[0039] Figure 3 it is a schematic diagram of the adjustable valve of the present application;

[0040] Figure 4 Schematic diagram for screening target gel particles;

[0041] Figure 5 Schematic diagram for morphological change process of single gel particle when passing through throat;

[0042] Figure 6 Schematic diagram for critical passing pressure p of single gel particle when passing through throat c Schematic diagram for relationship with restriction ratio;

[0043] Figure 7 Schematic diagram for critical passing pressure p of gel particles with different elastic modulus when passing through throat c Schematic diagram for relationship with restriction ratio;

[0044] Wherein, 1, microsyringe for storing gel particles, 2, microsyringe for injecting displacement phase fluid, 3, microsyringe for screening gel particles, 4, first microsyringe pump, 5, second microsyringe pump, 6, third microsyringe pump, 7, pipeline, 8, single-channel microfluidic chip, 9, tail liquid collector, 10, T-shaped pipeline connector, 11, controller, 12, high-speed camera, 13, microscope, 14, computer, 15, filter, 16, gel particle injection port, 17, gel particle screening port, 18, waste liquid discharge port, 19, adjustable valve, 20, continuous phase injection port, 21, S-shaped channel, 22, converging channel, 23, narrow throat, 24, gel particle discharge port, 25, main migration microchannel. DETAILED DESCRIPTION

[0045] The application will be further limited by the following description and examples, but not limited thereto.

[0046] Example 1

[0047] A non-continuous phase seepage experiment device containing gel particles, comprising a micro-liquid injection system, a pressure acquisition and transmission system, a microscopic observation system, a particle screening and migration system in a microchannel;

[0048] The micro-liquid injection system is used for injecting different types of gel particle solutions; the pressure acquisition and transmission system is used for monitoring pressure fluctuation characteristics of gel particles in the process of migration and plugging in the microchannel; the microscopic observation system is used for visualized research on migration state and plugging mode of gel particles in the microchannel; and the particle screening and migration system in the microchannel is used for accurately screening target gel particles.

[0049] The present application builds a non-continuous phase seepage experiment device, adopts a customized microfluidic chip to accurately screen the particle size of gel particles, adopts a high-precision pressure sensing system and a microscopic observation system, and monitors the migration form, existence state and pressure fluctuation of the gel particles under different particle sizes, different elastic moduli and different quantities in the single-channel microfluidic chip 8 in real time. According to the change rule of the critical pressure of the gel particles passing through a single throat under different conditions, the migration change characteristics of the gel particles in the pore throat can be quantitatively analyzed, and a gel particle deformation migration characterization model is established. The gel particle deformation migration characterization model has important guiding significance for studying the seepage mechanism of the gel particles in the porous medium and the optimal matching relationship between the particle size and the pore throat size.

[0050] Example 2

[0051] A non-continuous phase seepage experiment device containing gel particles according to example 1, as shown in Figure 1 The difference lies in that:

[0052] The micro-liquid injection system includes a micro-injection pump, a micro-injector, pipeline valves and a pipeline 7 (a PTFE pipe with an outer diameter of 1 / 8 in and an inner diameter of 1 / 16 in);

[0053] The micro-injector is matched with the micro-injection pump, and the micro-injector is fixed on the micro-injection pump. The liquid in the micro-injector is pumped into the particle screening and migration system in the microchannel through the pipeline 7 by the micro-injection pump.

[0054] The pressure collection and transmission system includes a T-shaped pipeline connector 10, a pressure sensor, a controller 11, a communication module and a computer 14; the T-shaped pipeline connector 10, the controller 11, the communication module and the computer 14 are connected in sequence.

[0055] The T-shaped pipeline connector 10 is connected to the pipeline 7. When the fluid passes through the T-shaped pipeline connector 10, the internal pressure of the pipeline is sensed by the pressure sensor through the T-shaped pipeline connector 10, and then data collection and control are performed by the controller 11 (up to 4 sensors can be controlled), and finally data transmission is performed by the communication module and the computer 14.

[0056] The microscopic observation system includes a high-speed camera 12 and a microscope 13.

[0057] First, the target gel particles are captured by the microscope 13, and then the high-speed camera 12 is used to observe the clogging and migration of the target gel particles in the microchannel in detail.

[0058] The particle migration system in the microchannel includes single-channel microfluidic chips 8 with different structures and a tail liquid collector 9.

[0059] The present application establishes a quantitative characterization model for gel particle deformation passing according to critical pressure and elastic modulus of gel particle deformation passing under different conditions, ratio of particle size and throat, interfacial tension and other factors.

[0060] As shown in Figure 2 The single-channel microfluidic chip 8 includes a gel particle injection port 16, a gel particle screening port 17, a waste liquid discharge port 18, an adjustable valve 19, a continuous phase injection port 20, a main transport microchannel 25, an S-shaped channel 21, a converging channel 22, a narrow throat 23, and a gel particle discharge port 24; wherein, Figure 3 It is a three-dimensional schematic view of the adjustable valve 19 position.

[0061] The gel particle injection port 16 and the waste liquid discharge port 18 are located on the same straight line, the channel where the gel particle screening port 17 is located is perpendicular to the communication channel of the gel particle injection port 16 and the waste liquid discharge port 18; the main transport microchannel 25 and the communication channel of the gel particle injection port 16 and the waste liquid discharge port 18 form an angle of 125°-150° (135°), the channel where the continuous phase injection port 20 is located is perpendicular to the main channel, and the main transport microchannel 25, the S-shaped channel 21, the converging channel 22, the narrow throat 23, and the gel particle discharge port are sequentially connected;

[0062] The adjustable valve 19 is located at the leftmost end of the main transport microchannel 25, which controls the communication of the screening channel and the transport channel. The S-shaped channel 21 reduces the interference caused by the opening and closing of the adjustable valve 19 on the pressure fluctuation in the channel.

[0063] The gel particle injection port 16 injects a gel particle solution, the gel particle screening port 17 drives target gel particles into the main transport microchannel 25 by injecting a continuous phase fluid, the waste liquid discharge port 18 is used to discharge non-target gel particles, the continuous phase injection port 20 is used to inject a continuous phase fluid, the main transport microchannel 25 is used for gel particle transport, the converging channel 22 is used to simulate the transition part of the actual pore throat connection, the narrow throat 23 is used to simulate the actual throat, and the gel particle discharge port 24 is used to discharge the fluid inside the microchannel.

[0064] The microsyringe pump includes a constant flow microsyringe pump and a constant pressure microsyringe pump, which are respectively used to set a specific flow and a specific injection pressure. The flow of the constant flow microsyringe pump can be adjusted in the range of 1 μl / h-1800 ml / h, and the constant pressure of the constant pressure microsyringe pump can be up to 300 kPa with an accuracy of ±2%.

[0065] The microsyringe is matched with the microsyringe pump, and the microsyringe is fixed on the microsyringe pump, and the range of the microsyringe can be 10 ml, 25 ml, 50 ml.

[0066] The material of the pipeline 7 is polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP) or Tygon silica gel, and the inner diameter of the pipeline 7 is 0.039mm-2.54mm.

[0067] The pressure sensor has three ranges of 0-250kPa, 0-800kPa and 0-1800kPa, and the accuracy is 1%.

[0068] The high-speed camera 12 has a maximum frame rate of 224,000fps, and the microscope 13 has a magnification of 1.25 times, 5 times, 20 times or 50 times, and the highest resolution is 0.1μm.

[0069] The material of the single-channel microfluidic chip 8 is polymethyl methacrylate (PMMA) or polydimethylsiloxane (PDMS); the minimum width and depth of the etched microchannel of the PMMA single-channel microfluidic chip 8 are both 50μm, the PMMA single-channel microfluidic chip 8 can be disassembled and cleaned, and when the particle size of the gel particles is higher than 50μm, it is recommended to use the PMMA single-channel microfluidic chip 8; the minimum width and depth of the etched microchannel of the PDMS single-channel microfluidic chip 8 are both 5μm. The service life of the PDMS single-channel microfluidic chip 8 is shorter, and the PDMS single-channel microfluidic chip 8 is an integrated chip that cannot be disassembled, and it is recommended to use the PDMS single-channel microfluidic chip 8 when the particle size of the gel particles is in the range of 1-50μm. The thickness of the single-channel microfluidic chip 8 is 0.5cm-1.5cm.

[0070] The micro-liquid injection system further comprises a filter 15 connected to the microsyringe for filtering large-particle impurities in the solution to prevent the single-channel microfluidic chip 8 from being blocked.

[0071] Example 3

[0072] A method for determining the critical pressure by using the non-continuous phase seepage experimental device containing gel particles described in Example 2, comprising the following steps:

[0073] Monitoring the pressure fluctuation generated by different types and quantities of gel particles in the single channel;

[0074] Establishing the relationship between the critical pressure and the restriction ratio when gel particles with different elastic moduli and different concentrations pass through the throat, and determining the limit of gel particle rupture;

[0075] Considering the factors such as elastic modulus, gel particle size radius and throat radius when the gel particles deform and pass through the throat, a quantitative characterization model for the gel particles deforming and passing through the throat is established.

[0076] Specifically, the method comprises the following steps:

[0077] (1) Through the third micro-syringe pump 6, the continuous phase fluid in the micro-syringe 3 for screening gel particles is injected into the single-channel microfluidic chip 8 through the gel particle screening port 17, and the whole single-channel microfluidic chip 8 is saturated with the continuous phase fluid, and the adjustable valve 19 is closed;

[0078] (2) Through the first micro-syringe pump 4, the spherical gel particles in the micro-syringe 1 for storing gel particles are injected at a low flow rate of 0.1-2 μl / min, and the gel particles have been diluted to a very dilute state.

[0079] (3) When the target gel particles are observed, the adjustable valve 19 is slowly opened only to a certain height, and the target gel particles are quickly driven into the main migration micro-channel 25 by adjusting the flow rate of the third micro-syringe pump 6, and the adjustable valve 19 is closed to make the target gel particles migrate along the main migration micro-channel 25;

[0080] (4) Through the second micro-syringe pump 5, the injection displacement phase fluid in the micro-syringe 2 for injecting displacement phase fluid is injected at an injection flow rate of B 0.1-10 μl / min through the continuous phase injection port 20, and the target gel particles are continuously pushed through the S-shaped channel 21 to the convergent channel 22;

[0081] (5) The high-speed camera 12 and the microscope 13 are used to collect the particle migration form in real time, and the pressure sensor is used to monitor the pressure change of the spherical gel particles passing through the narrow throat 23 to determine the critical pressure. The critical pressure refers to the maximum pressure at which the spherical gel particles can deform to pass through the narrow throat 23. When the particle size of the gel particles is larger than the diameter of the narrow throat 23, the gel particles migrate to the position of the convergent channel 22, and as the gel particles continue to migrate forward, the particles will be deformed by extrusion, and a blockage will occur at the narrow throat 23. At this time, the injection pressure will continue to rise, and when the injection pressure rises to a certain value, the gel particles will continue to migrate forward, and finally the channel will be unblocked. At this time, the maximum pressure at which the particles can deform to pass through the narrow throat 23 is defined as the critical passing pressure. Wherein, Figure 4 It is a schematic diagram for screening target gel particles; Figure 5 It is a schematic diagram of the shape change process of a single gel particle passing through a throat; Figure 6 It is a schematic diagram of the relationship between the critical passing pressure p c and the restriction ratio, wherein the throat radius is 100 μm, and the elastic modulus of the gel particles is 12 Pa; Figure 7 It is a schematic diagram of the relationship between the critical passing pressure p cThe relationship between the restriction ratio and the pressure, the throat diameter ratio and the elastic modulus can be obtained from the relationship diagram, and a quantitative characterization model of the critical passing pressure of the gel particles passing through the throat at a certain flow rate and the restriction ratio (the ratio of the gel particle to the throat radius) and the elastic modulus can be established, and the change relationship of the gel particle rupture limit with the restriction ratio and the elastic modulus can be established.

[0082] All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the protection scope of the present application.

Claims

1. A non-continuous phase flow experiment device containing gel particles, characterized in that, The micro-liquid injection system, the pressure collection and transmission system, the microscopic observation system, and the particle screening and migration system in the micro-channel are included. The micro-liquid injection system is used for injecting different types of gel particle solutions. The pressure collection and transmission system is used for monitoring the pressure fluctuation characteristics of gel particles during migration and plugging in the micro-channel. The microscopic observation system is used for visualizing the migration state and plugging mode of gel particles in the micro-channel. The micro-liquid injection system includes a micro-injection pump, a micro-injector, and a pipeline. The micro-injector is matched with the micro-injection pump, and the micro-injector is fixed on the micro-injection pump. The micro-injection pump is used for pumping the liquid in the micro-injector into the particle screening and migration system in the micro-channel through the pipeline. The pressure collection and transmission system includes a T-shaped pipeline connector, a pressure sensor, a controller, a communication module, and a computer. The T-shaped pipeline connector, the controller, the communication module, and the computer are sequentially connected. The T-shaped pipeline connector is connected to the pipeline. When the fluid passes through the T-shaped pipeline connector, the internal pressure of the pipeline is sensed by the pressure sensor through the T-shaped connector. Subsequently, data collection and control are performed by the controller.

2. The non-continuous phase flow experiment device containing gel particles according to claim 1, characterized in that, Finally, data transmission is performed by the communication module and the computer.

3. The non-continuous phase flow experiment device containing gel particles according to claim 1, characterized in that, The microscopic observation system includes a high-speed camera and a microscope.

4. The non-continuous phase flow experiment device containing gel particles according to claim 1, characterized in that, First, the microscope is used to capture the observed target gel particles. Subsequently, the high-speed camera is used to observe the plugging and migration mode of the target gel particles in the micro-channel. The particle migration system in the micro-channel includes single-channel microfluidic chips with different structures. The single-channel microfluidic chip includes a gel particle injection port, a gel particle screening port, a waste liquid discharge port, an adjustable valve, a continuous phase injection port, a main migration micro-channel, an S-shaped channel, a convergent channel, a narrow throat, and a gel particle discharge port. The gel particle injection port and the waste liquid discharge port are located on the same straight line. The channel where the gel particle screening port is located is perpendicular to the communication channel of the gel particle injection port and the waste liquid discharge port. The main migration micro-channel and the communication channel of the gel particle injection port and the waste liquid discharge port form an included angle of 125°-150°. The channel where the continuous phase injection port is located is perpendicular to the main channel. The main migration micro-channel, the S-shaped channel, the convergent channel, the narrow throat, and the gel particle discharge port are sequentially connected. The adjustable valve is located at the leftmost end of the main migration micro-channel. The micro-injection pump includes a constant flow micro-injection pump and a constant pressure micro-injection pump, which are respectively used for setting specific flow and specific injection pressure. The material of the pipeline is polytetrafluoroethylene, fluorinated ethylene propylene copolymer, or Tygon silicone. The inner diameter of the pipeline is 0.039mm-2.54mm. The material of the single-channel microfluidic chip is polymethyl methacrylate or polydimethylsiloxane. The thickness of the single-channel microfluidic chip is 0.5cm-1.5cm.

5. The non-continuous phase flow experiment device containing gel particles according to claim 1, characterized in that, The micro-liquid injection system further comprises a filter connected to the micro-syringe for filtering large-particle impurities in the solution.

6. A method for determining the critical pressure by using the non-continuous phase flow experiment device of the gel-containing particle according to claim 2, characterized in that, The method comprises the following steps: (1) The continuous phase fluid in the micro-syringe for screening gel particles is injected into the single-channel microfluidic chip through the gel particle screening port by the third micro-syringe pump, and the whole single-channel microfluidic chip is saturated with the continuous phase fluid, and the adjustable valve is closed; (2) The spherical gel particles in the micro-syringe for storing gel particles are injected through the gel particle injection port at an injection flow rate of 0.1-2 μl / min by the first micro-syringe pump; (3) When the target gel particles are observed, the adjustable valve is slowly opened, the target gel particles are quickly driven into the main migration micro-channel by adjusting the flow rate of the third micro-syringe pump, and the adjustable valve is closed to make the target gel particles migrate along the main migration micro-channel; (4) The injection displacement phase fluid in the micro-syringe for injecting displacement phase fluid is injected through the continuous phase injection port at an injection flow rate of 0.1-10 μl / min by the second micro-syringe pump, and the target gel particles are continuously pushed through the S-shaped channel to the convergent channel; (5) The high-speed camera and the microscope are used to collect the particle migration form in real time, the pressure sensor is used to monitor the pressure change of the spherical gel particles during the process of passing through the narrow throat, and the critical pressure is determined, wherein the critical pressure refers to the maximum pressure under which the spherical gel particles can deform to pass through the narrow throat.

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