A sub-micron microfluidic experimental device and its usage method under high temperature and high pressure conditions

Abstract

This application relates to the field of microscopic observation technology, and discloses a sub-micron microfluidic experimental device and a usage method under high temperature and high pressure conditions. The device includes a heating and heat preservation jacket; the heating and heat preservation jacket wraps the chamber body of the observation device; the upper cover of the chamber body is arranged above the chamber body of the observation device; the water circulation cavity is hermetically arranged above the upper cover of the chamber body; the microscopic observation port is arranged above the water circulation cavity; the rotary bearing is arranged on the outer wall surface of the microscopic observation port and is located inside the water circulation cavity; the microchip is arranged inside the microchip holder; the microchip holder is arranged on the side of the chamber body of the observation device; the water circulation temperature detection and flow rate controller is connected to the water-cooled circulation outlet and the rotary bearing of the water circulation cavity through pipelines and wires respectively; the water-cooling device is connected to the water circulation temperature detection and flow rate controller and the water-cooled circulation inlet through pipelines respectively. This application can realize high-precision microfluidic visualization experiments under high temperature and high pressure conditions.

Description

Technical Field

[0001] This application relates to the field of microscopic observation technology, and particularly relates to a sub-micron level microfluidic experimental device and a usage method under high temperature and high pressure conditions. Background Art

[0002] Studying the laws of fluid flow in microscopic porous media is an important research method in multiple basic fields, and its application scope covers fluid mechanics, energy development, environmental governance, materials science, biomedicine, etc. Taking the oil and gas field as an example, understanding the flow laws of oil, gas, and water in porous media is crucial for improving oil and gas recovery, optimizing exploitation plans, and predicting production capacity. The combination of microfluidic chip technology and optical microscopes creates conditions for intuitively studying the fluid occurrence state and migration mechanism at the pore scale. For deep high-temperature and high-pressure oil and gas reservoirs, a microfluidic chip holder is usually used to load microchips to conduct multiphase seepage experiment simulations under high temperature and high pressure conditions. Under the existing technical conditions, the channel size of microfluidic chips fabricated by conventional wet etching is usually between several micrometers and several hundred micrometers. High-end manufacturing processes (such as lithography) can achieve the fabrication of channels with a size of 1 micrometer or even sub-micron level. Channels of this level can reflect the pores of low-permeability oil and gas reservoirs. As the channel size of microfluidic chips continues to decrease, if precise observation of fluid migration is to be achieved through microfluidic experiments under high temperature and high pressure conditions, higher requirements are imposed on microscopes and microfluidic model holders.

[0003] The prior art CN 118130756 A discloses a composite device and experimental method for tight sandstone rock electricity experiments and teaching. This experimental device uses a microscope combined with image processing technology to observe the seepage process and distribution state of multiphase fluids in a microscopic model chip, but it cannot simulate the real formation environment of high temperature and high pressure. The prior art CN118010587 A discloses a high temperature and high pressure microscopic visualization microscopic displacement model clamping device and a usage method. This experimental device uses a vacuum layer to ensure stable formation temperature conditions during the microscopic visualization displacement experiment, and at the same time, continuous observation in different directions of the microscopic model can be achieved. However, this clamping device is large in size and is only suitable for a stereomicroscope.

[0004] The necessary experimental conditions for carrying out high-temperature and high-pressure microfluidics are a microfluidic chip holder that can withstand high-temperature and high-pressure conditions. Currently, the observation method for microfluidic experiments under high-temperature and high-pressure conditions is a stereomicroscope. The advantages of a stereomicroscope are its long focal length and large observation field of view. However, its magnification is limited, and the effective observation size is usually dozens of micrometers or more. For the corresponding optical microscope or metallurgical microscope, the fluid situation in the channel within a range of 10 micrometers can be clearly observed. However, the problem is that the focal length is too short. Taking a 100x objective lens as an example, the focal length is about 4 mm. In the currently disclosed technologies, the thickness of the observation window of the high-temperature and high-pressure microfluidic holder generally exceeds 2 cm, far beyond the focal length range of high-power objective lenses, and cannot effectively support the research on the flow law of high-temperature and high-pressure fluids in sub-10-micrometer channels. Summary of the Invention

[0005] The purpose of this application is to provide a sub-micron microfluidic experimental device under high-temperature and high-pressure conditions, so as to fully consider the problems of small focal length and high-temperature intolerance of high-power objective lenses of conventional optical microscopes when observing high-precision microscopic models under different pressure conditions, and realize high-precision microfluidic visualization experiments under high-temperature and high-pressure conditions.

[0006] In order to achieve the above purpose, the following technical solutions are adopted:

[0007] In the first aspect, this application provides a sub-micron microfluidic experimental device under high-temperature and high-pressure conditions, including a heating and insulation jacket, an observation device chamber main body, an upper cover of the chamber main body, a water circulation cavity, a microscopic observation port, a rotary bearing, a microscopic chip, a microscopic chip holder, a water circulation temperature detection and flow rate controller, a water cooling device, a heating controller, and a microscope;

[0008] The heating and insulation jacket wraps the observation device chamber main body; the upper cover of the chamber main body is arranged above the observation device chamber main body; the water circulation cavity is hermetically arranged above the upper cover of the chamber main body; the microscopic observation port is arranged above the water circulation cavity; the rotary bearing is arranged on the outer wall surface of the microscopic observation port and is located inside the water circulation cavity; the microscopic chip is arranged inside the microscopic chip holder; the microscopic chip holder is hermetically arranged on the side of the observation device chamber main body; the water circulation temperature detection and flow rate controller is connected to the water-cooled circulation outlet of the water circulation cavity and the rotary bearing through pipelines and wires respectively; the water cooling device is connected to the water circulation temperature detection and flow rate controller and the water-cooled circulation inlet of the water circulation cavity through pipelines respectively; the microscope is arranged above the microscopic observation port.

[0009] Furthermore, it further includes a glass observation window and a glass observation window fixing plate, and the glass observation window is hermetically arranged at the bottom of the water circulation cavity through the glass observation window fixing plate.

[0010] Further, the distance between the glass observation window and the microchip does not exceed 0.1 mm.

[0011] Further, a water circulation rotating blade is provided on the outer wall surface of the rotating bearing. When the rotating bearing operates, the water circulation rotating blade rotates around the central axis of the microscopic observation port to accelerate the water circulation flow rate.

[0012] Further, the microchip holder includes a microchip fixing plate, a microchip clamping plate and a connecting component. The microchip is placed on the microchip fixing plate. The microchip fixing plate is fixedly connected to the microchip clamping plate. The connecting component is fixedly connected to the microchip clamping plate. The connecting component is used to sealably assemble the microchip holder on the side of the observation device chamber body. A displacement inlet and a displacement outlet are provided on the connecting component. The displacement inlet and the displacement outlet are connected to the microchip provided on the microchip clamping plate through pipelines.

[0013] Further, it further includes a first intermediate container, a second intermediate container, a double-cylinder displacement pump and a fluid metering container. The first intermediate container and the second intermediate container are respectively assembled on the double-cylinder displacement pump. The first intermediate container and the second intermediate container are respectively connected to the displacement inlet through pipelines. The fluid metering container is connected to the displacement outlet through a pipeline.

[0014] Further, a hydraulic oil through hole is provided on the microchip clamping plate. A confining pressure inlet and a confining pressure outlet are provided on the pressure cover of the chamber body. A confining pressure pump is further included. The confining pressure pump is connected to the confining pressure inlet through a pipeline.

[0015] In a second aspect, the present application provides a method for using a sub-micron microfluidic experimental device under high temperature and high pressure conditions as described above. The method includes:

[0016] Assembling a sub-micron microfluidic experimental device under high temperature and high pressure conditions;

[0017] Inlaying an objective lens waterproof sheet on the inner lens of the objective lens of the microscope; placing the objective lens into the microscopic observation port, turning on the heating controller, and setting it to the constant temperature mode, heating the observation device chamber body to the target temperature T; after reaching the target temperature T, turning on the water circulation temperature detection and flow rate controller and the water cooling device, controlling the rotation speed of the water circulation rotating blade and monitoring the water temperature at the water cooling circulation outlet in real time to ensure that the water temperature is maintained under the temperature that the objective lens of the microscope can withstand;

[0018] Turn on the confining pressure pump and slowly inject hydraulic oil into the interior of the observation device chamber body until no bubbles appear at the confining pressure outlet. Then plug the confining pressure outlet and turn on the constant pressure mode of the confining pressure pump so that the hydraulic oil fills the space between the microchip and the glass observation window through the hydraulic oil port, keeping a constant confining pressure of the first pressure P1 on both the upper and lower sides of the microchip.

[0019] Adjust the height of the objective lens for focusing until the microscopic structure inside the microchip is clearly observed.

[0020] Open the switch of the first intermediate container filled with water, turn on the double-cylinder displacement pump, saturate the microchip with water, observe the migration of the water phase in the microchip, maintain the internal pressure of the micro-model at the second pressure P2, and after saturation with water is completed, close the displacement inlet.

[0021] Open the switch of the second intermediate container filled with gas, turn on the double-cylinder displacement pump, increase the pressure of the gas to the third pressure P3, where P3 > P2; open the displacement inlet, inject gas into the microchip, and at the same time open the displacement outlet, and observe and record the seepage process of gas and water in the microchip through the microscope.

[0022] Further, assemble the sub-micron microfluidic experimental device under high temperature and high pressure conditions in the following manner:

[0023] Place the microchip on the microchip fixing plate and fix it on the microchip clamping plate with fixing bolts to obtain a microchip fixture; hermetically assemble the microchip fixture into the inlet on the side wall of the observation device chamber body.

[0024] Fix the upper cover of the chamber body on the observation device chamber body with bolts; place the glass observation window on the sapphire glass observation window fixing plate and fix it at the bottom of the water circulation cavity with bolts; screw the water circulation cavity into the hole in the middle of the upper cover of the chamber body through threads and rubber sealing rings; screw the microscopic observation port into the interior of the water circulation cavity through threads.

[0025] After wrapping the heating and insulation jacket around the observation device chamber body, connect it to the heating controller through wires; connect the confining pressure pump to the confining pressure inlet on the upper cover of the chamber body through pipelines; connect the water circulation temperature detection and flow rate controller to the water-cooled circulation outlet and the water-cooling device on the water circulation cavity through pipelines respectively; connect the water-cooling device to the water-cooled circulation inlet on the water circulation cavity through pipelines; connect the double-cylinder displacement pump to the first intermediate container filled with water and the second intermediate container filled with gas through pipelines respectively; connect the first intermediate container and the second intermediate container to the displacement inlet 16 on the microchip fixture.

[0026] Connect the vacuum pump to the displacement outlet on the microchip fixture, turn on the vacuum pump, extract the air in the microchip, then close the outlet switch and connect the fluid metering container.

[0027] Further, after observing and recording the seepage process of gas and water in the microchip through a microscope, the usage method further includes a step of ending the experiment, and the step of ending the experiment includes:

[0028] Turn off the double-cylinder displacement pump and stop heating. After the temperature reaches room temperature, turn off the confining pressure pump. After unloading the confining pressure, turn off the water circulation temperature detection and flow rate controller and the water cooling device, and then clean.

[0029] The beneficial effects of this application are as follows:

[0030] The focal length of the high-power objective lens of a conventional optical microscope is usually within 1 cm and it cannot withstand high temperatures. However, the device proposed in this application can use a high-power optical microscope objective lens to closely observe a high-precision microchip under high-temperature and high-pressure conditions to conduct microfluidic visualization experiments. Description of the Drawings

[0031] Figure 1 Shows a schematic cross-sectional view of the structure of a sub-micron microfluidic experimental device under high-temperature and high-pressure conditions according to an embodiment of the present application.

[0032] Figure 2 Shows a three-dimensional schematic diagram of the microchip holder of a sub-micron microfluidic experimental device under high-temperature and high-pressure conditions according to an embodiment of the present application.

[0033] Figure 3 Shows a schematic diagram of the overall layout of a sub-micron microfluidic experimental device under high-temperature and high-pressure conditions according to an embodiment of the present application.

[0034] Figure 4 Shows a microchip physical observation diagram under a 100-fold metallographic microscope objective lens according to an embodiment of the present application.

[0035] Reference Numerals:

[0036] 1 - Heating and heat preservation sleeve; 2 - Observation device chamber body; 3 - Upper gland of the chamber body; 4 - Fixing bolt; 5 - Confining pressure inlet; 6 - Water-cooling circulation inlet; 7 - Microscopic observation port; 8 - Water-cooling circulation outlet; 9 - Rotating bearing; 10 - Rubber sealing ring I; 11 - Confining pressure outlet; 12 - Water circulation cavity; 13 - Water circulation rotating blade; 14 - Objective lens waterproof sheet; 15 - Glass observation window; 16 - Displacement inlet; 17 - Displacement outlet; 18 - Rubber sealing ring II; 19 - Microscopic chip; 20 - Glass observation window fixing plate; 21 - Microscopic chip fixing plate; 22 - Microscopic chip clamping plate; 23 - Confining pressure pump; 24 - Microscope; 25 - Water circulation temperature detection and flow rate controller; 26 - Water-cooling device; 27 - Microscopic observation device; 28 - First intermediate container; 29 - Second intermediate container; 30 - Double-cylinder displacement pump; 31 - Heating controller; 32 - Fluid metering container; 33 - Hydraulic oil port; 34 - Connection assembly. Detailed implementation manners

[0037] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0038] The following combines the drawings and embodiments to further describe in detail the specific implementation manners of the present application.

[0039] Embodiment 1:

[0040] The embodiment of the present application provides a sub-micron microfluidic experimental device under high temperature and high pressure conditions, as Figures 1 to 3As shown in the figure, the sub-micron microfluidic experimental device under high temperature and high pressure conditions includes a heating and insulation jacket 1, an observation device chamber main body 2, an upper cover 3 of the chamber main body, a water circulation cavity 12, a microscopic observation port 7, a rotary bearing 9, a microscopic chip 19, a microscopic chip holder, a water circulation temperature detection and flow rate controller 25, a water cooling device 26, a heating controller 31, and a microscope 24; the heating and insulation jacket 1 wraps the observation device chamber main body 2; the upper cover 3 of the chamber main body is arranged above the observation device chamber main body 2 through fixing bolts 4; the water circulation cavity 12 is hermetically arranged above the upper cover 3 of the chamber main body; the microscopic observation port 7 is arranged above the water circulation cavity 12; the rotary bearing 9 is arranged on the outer wall surface of the microscopic observation port 7 and is located inside the water circulation cavity 12; the microscopic chip 19 is arranged inside the microscopic chip holder; the microscopic chip holder is hermetically arranged on the side surface of the observation device chamber main body 2; the water circulation temperature detection and flow rate controller is connected to the water cooling circulation outlet 8 of the water circulation cavity 12 and the rotary bearing 9 through pipelines and wires respectively; the water cooling device 26 is connected to the water circulation temperature detection and flow rate controller and the water cooling circulation inlet 6 of the water circulation cavity 12 through pipelines respectively; the microscope 24 is arranged above the microscopic observation port 7.

[0041] The heating and insulation jacket 1 is a structure with a built-in constant temperature heating and insulation function. For example, the heating and insulation jacket 1 can be composed of a heating component, a temperature sensing component, and a heat insulation layer connected together. Among them, the heating component is attached to the observation device chamber main body 2, the temperature sensing component can be arranged in the heat insulation layer, and both the heating component and the temperature sensing component are connected to the heating controller 31. The heating controller 31 controls the heating component to work, and according to the set target temperature, combined with the temperature signal collected by the temperature sensing component, after the temperature signal reaches the target temperature, it controls the heating component to stop working. Of course, the temperature sensing component can also be arranged outside the heating component, and it contacts the outer side of the observation device chamber main body 2, so that the collected temperature signal can better reflect the temperature of the observation device chamber main body 2.

[0042] The observation device chamber main body 2 is used to assemble and fix the microscopic chip holder with the microscopic chip 19. The upper cover 3 of the chamber main body fixed at the upper end of the observation device chamber main body 2 facilitates the installation of the water circulation cavity 12. For example, the water circulation cavity 12 can be screwed into the hole provided in the middle of the upper cover 3 of the chamber main body through threads and a rubber sealing ring I 10; at the same time, the microscopic observation port 7 can be screwed into the inside of the water circulation cavity 12 through threads, which is conducive to the installation of the microscope 24. The microscope 24 can be selected as a metallurgical microscope.

[0043] Cooling water or heat-conducting oil flows inside the water circulation cavity 12, and the temperature is regulated by the water cooling device 26 and the water circulation temperature detection and flow rate controller 25 to prevent local overheating and ensure the cooling effect of the objective lens of the microscope 24. The function of the water circulation temperature detection and flow rate controller 25 is to detect the circulating water temperature and flow rate of the water circulation cavity 12 and regulate the rotation speed of the rotary bearing 9 according to the detected circulating water temperature. The specific structure of the water circulation temperature detection and flow rate controller 25 can be, for example, a structure composed of a temperature sensor and a control chip. The temperature sensor can be assembled on the pipeline corresponding to the temperature to be detected, and the control chip can be integrated with the temperature sensor. The control chip is electrically connected to the temperature sensor and is used to obtain the circulating water temperature collected by the temperature sensor. The rotary bearing 9 is an electric rotary shaft, specifically a structure that realizes rotation by driving the shaft with a motor. Among them, a water circulation rotary blade 13 is provided on the outer wall surface of the rotary bearing 9. When the rotary bearing 9 operates, the water circulation rotary blade 13 rotates around the central axis of the microscopic observation port to accelerate the water circulation flow rate. The control chip can adjust the flow rate by controlling the rotation speed of the rotary bearing 9. For example, when the circulating water temperature is too high, the rotation speed can be appropriately increased to generate centrifugal force to accelerate the water circulation flow rate. The water cooling device 26 is a device that can achieve cooling. For example, the water cooling device 26 can be a refrigerator, and the circulating water is cooled by the refrigerator and then circulated.

[0044] In some embodiments, as Figure 1 shown, the sub-micron microfluidic experimental device under high temperature and high pressure conditions further includes a glass observation window 15 and a glass observation window fixing plate 20. The glass observation window 15 is hermetically arranged at the bottom of the water circulation cavity 12 through the glass observation window fixing plate 20.

[0045] Exemplarily, the glass observation window 15 can be placed on the glass observation window fixing plate 20 and fixed to the bottom of the water circulation cavity 12 by bolts. The glass observation window 15 can be made of sapphire glass.

[0046] In some embodiments, as Figure 1 shown, the distance between the glass observation window 15 and the microchip 19 does not exceed 0.1 mm. The thickness of the glass observation window 15 can be set to 3.9 mm. During observation, the objective lens of the microscope 24 can be closely attached to the glass observation window 15, and the minimum distance from the microchip 19 can be controlled within 4 mm.

[0047] In some embodiments, as Figure 2As shown, the microchip holder includes a microchip fixing plate 21, a microchip clamping plate 22, and a connection component 34. The microchip 19 is placed on the microchip fixing plate 21. The microchip fixing plate 21 is fixedly connected to the microchip clamping plate 22. The connection component 34 is fixedly connected to the microchip clamping plate 22. The connection component 34 is used to sealably assemble the microchip holder on the side of the observation device chamber body 2. The connection component 34 is provided with a displacement inlet 16, a displacement outlet 17, and a rubber seal ring II. The displacement inlet 16 and the displacement outlet 17 are connected to the microchip 19 provided on the microchip clamping plate 21 through pipelines. The connection component 34 can be assembled on the microchip clamping plate 22 by bolts in cooperation with the screw holes provided on the microchip clamping plate 22. The pipelines connected to the displacement inlet 16 and the displacement outlet 17 can communicate with the space where the microchip 19 is located through the pipe holes provided on the microchip clamping plate 22.

[0048] In some embodiments, as Figure 2 and Figure 3 shown, the submicron-scale microfluidic experimental device under high temperature and high pressure conditions further includes a first intermediate container 28, a second intermediate container 29, a double-cylinder displacement pump 30, and a fluid metering container 32. The first intermediate container 28 and the second intermediate container 29 are respectively assembled on the double-cylinder displacement pump 30. The first intermediate container 28 and the second intermediate container 29 are respectively connected to the displacement inlet 16 through pipelines. The fluid metering container 32 is connected to the displacement outlet 17 through a pipeline.

[0049] The functions of the first intermediate container 28 and the second intermediate container 29 are to load different displacement media. For example, the first intermediate container 28 can be filled with a liquid medium, and the second intermediate container 29 can be filled with a gas medium. Control valves are respectively provided on the pipelines connecting the first intermediate container 28 and the second intermediate container 29 to the displacement inlet 16. These two corresponding control valves respectively serve as the switches of the first intermediate container 28 and the second intermediate container 29. The double-cylinder displacement pump 30 is used to provide displacement power for the first intermediate container 28 or the second intermediate container 29. After the displacement is completed, the displacement media loaded in the first intermediate container 28 and the second intermediate container 29 will enter the fluid metering container 32 through the displacement outlet 17. The fluid metering container 32 can be configured with metering components, such as a mass sensor, a flow sensor, etc., for measuring data such as the mass and flow rate of the displacement medium according to experimental needs.

[0050] In some embodiments, as Figures 1 to 3 shown, a hydraulic oil port 33 is provided on the microchip clamping plate 22. A confining pressure inlet 5 and a confining pressure outlet 11 are provided on the gland 3 of the chamber body. A confining pressure pump 23 is further included. The confining pressure pump 23 is connected to the confining pressure inlet 5 through a pipeline.

[0051] The function of the confining pressure pump 23 is to pressurize the microchip 19 through the confining pressure inlet 5 and the hydraulic oil through-hole 33 to achieve a constant confining pressure when the confining pressure outlet 11 is blocked. When depressurizing, just turn off the confining pressure pump 23 and open the confining pressure outlet 11.

[0052] In some embodiments, as Figure 1 shown, an objective lens waterproof sheet 14 is inlaid on the inner lens of the objective lens of the microscope 24 to play a waterproof role.

[0053] Embodiment 2:

[0054] The embodiment of the present application provides a usage method of a sub-micron microfluidic experimental device under high temperature and high pressure conditions as described in Embodiment 1. The usage method includes the following steps:

[0055] Step 1, prepare the experimental equipment and tools, place the microchip 19 on the microchip fixing plate 21, and fix it on the microchip clamping plate 22 through fixing bolts; then place the entire microchip fixture into the inlet on the side wall of the observation device chamber body 2, and fix and seal it through fixing bolts and the sealing rubber ring II 18.

[0056] Step 2, fix the upper cover 3 of the chamber body on the observation device chamber body 2 through bolts; place the glass observation window 15 on the sapphire glass observation window fixing plate 20, and fix it on the bottom of the water circulation cavity 12 through bolts; screw the water circulation cavity 12 into the hole in the middle of the upper cover of the chamber body through threads and the rubber sealing ring I 10; screw the microscopic observation port 7 into the inside of the water circulation cavity 12 through threads.

[0057] Step 3, wrap the entire microscopic observation device 27 with the heating and insulation sleeve 1, and connect it to the heating controller 31 through wires; connect the confining pressure pump 23 to the confining pressure inlet 5 on the upper cover 3 of the chamber body through pipelines; connect the water circulation temperature detection and flow rate controller 25 to the water cooling circulation outlet 6 and the water cooling device 26 on the water circulation cavity 12 respectively through pipelines; connect the water cooling device 26 to the water cooling circulation inlet 8 on the water circulation cavity 12 through pipelines; connect the double-cylinder displacement pump 30 to the first intermediate container 28 filled with water and the second intermediate container 29 filled with gas respectively through pipelines; then connect the first intermediate container 28 and the second intermediate container 29 to the displacement inlet 16 on the microchip fixture.

[0058] Step 4, connect the vacuum pump to the displacement outlet 17 on the microchip fixture, then turn on the vacuum pump, extract the air in the microchip, then close the outlet switch, and connect the fluid metering container 32.

[0059] Step 5: Embed the objective lens waterproof sheet 14 on the internal lens of the metallurgical microscope objective lens to play a waterproof role; then place the objective lens into the microscopic observation port 7, turn on the heating controller 31, and set it to the constant temperature mode to heat the microscopic device to the target temperature T. At the same time, when the temperature rises to a certain level, turn on the water circulation temperature detection and flow rate controller 25 and the water cooling device 26, control the rotation speed of the water circulation rotating blade 13, and monitor the water temperature at the water cooling circulation outlet 8 in real time to ensure that the water temperature is maintained below the temperature that the objective lens of the metallurgical microscope can withstand.

[0060] Step 6: Turn on the confining pressure pump 23, slowly inject hydraulic oil into the main body of the observation device chamber 2 until there are no bubbles at the confining pressure outlet 11, then plug the confining pressure outlet 11 with a dead plug, and turn on the constant pressure mode of the confining pressure pump. The hydraulic oil will fill the space between the microscopic chip and the sapphire observation window through the hydraulic oil port 33, so that the upper and lower sides of the microscopic chip maintain a constant confining pressure of the first pressure P1.

[0061] Step 7: Subsequently, adjust the height of the objective lens for focusing until the microscopic structure inside the clear microscopic chip 19 can be observed.

[0062] Step 8: Open the switch of the first intermediate container 28 filled with water, turn on the double-cylinder displacement pump 30, saturate the microscopic chip 19 with water, observe the migration of the water phase in the microscopic chip, and then maintain the internal pressure of the microscopic model at the second pressure P2. After the water saturation is completed, close the inlet switch.

[0063] Step 9: Open the switch of the second intermediate container 29 filled with gas, turn on the double-cylinder displacement pump 30, first increase the pressure of the gas to the third pressure P3 (P3 > P2), then open the inlet switch, inject gas into the microscopic model, and at the same time open the outlet switch, and observe and record the seepage process of gas and water in the microscopic chip through the metallurgical microscope.

[0064] Step 10: After the experiment, turn off the double-cylinder displacement pump 30 and stop heating. After the temperature reaches room temperature, turn off the confining pressure pump 23, unload the confining pressure, then turn off the water circulation temperature detection and flow rate controller 25 and the water cooling device 26, and clean the device.

[0065] Finally, through the above steps, the physical observation diagram of the microscopic chip under the 100-fold metallurgical microscope objective lens is as Figure 4 shown, and it can be seen from Figure 4 that the device proposed in this application can use a high-power optical microscope objective lens to closely observe a high-precision microscopic chip under high-temperature and high-pressure conditions for microfluidic visualization experiments.

[0066] The above embodiments are only used to illustrate the present application and are not intended to limit the present application. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions also belong to the scope of the present application. The patent protection scope of the present application shall be defined by the claims.

Claims

1. A sub-micron scale microfluidic experimental device under high temperature and high pressure conditions, characterized in that, It includes a heating and heat preservation jacket, an observation device chamber body, an upper cover of the chamber body, a water circulation cavity, a microscopic observation port, a rotating bearing, a microscopic chip, a microscopic chip holder, a water circulation temperature detection and flow rate controller, a water cooling device, a heating controller, and a microscope; The heating and heat preservation jacket wraps the observation device chamber body; the upper cover of the chamber body is arranged above the observation device chamber body; the water circulation cavity is hermetically arranged above the upper cover of the chamber body; the microscopic observation port is arranged above the water circulation cavity; the rotating bearing is arranged on the outer wall surface of the microscopic observation port and inside the water circulation cavity; the microscopic chip is arranged inside the microscopic chip holder; the microscopic chip holder is hermetically arranged on the side of the observation device chamber body; the water circulation temperature detection and flow rate controller is connected to the water cooling circulation outlet of the water circulation cavity and the rotating bearing through pipelines and wires respectively; the water cooling device is connected to the water circulation temperature detection and flow rate controller and the water cooling circulation inlet of the water circulation cavity through pipelines respectively; the microscope is arranged above the microscopic observation port; The microscopic chip holder includes a microscopic chip fixing plate, a microscopic chip clamping plate, and a connecting component. The microscopic chip is placed on the microscopic chip fixing plate. The microscopic chip fixing plate is fixedly connected to the microscopic chip clamping plate. The connecting component is fixedly connected to the microscopic chip clamping plate. The connecting component is used to hermetically assemble the microscopic chip holder on the side of the observation device chamber body. A displacement inlet and a displacement outlet are arranged on the connecting component. The displacement inlet and the displacement outlet are connected to the microscopic chip arranged on the microscopic chip clamping plate through pipelines; Hydraulic oil through holes are arranged on the microscopic chip clamping plate. A confining pressure inlet and a confining pressure outlet are arranged on the upper cover of the chamber body. A confining pressure pump is also included. The confining pressure pump is connected to the confining pressure inlet through a pipeline.

2. The sub-micron level microfluidic experimental device under high temperature and high pressure conditions according to claim 1, characterized in that, It also includes a glass observation window and a glass observation window fixing plate. The glass observation window is hermetically arranged at the bottom of the water circulation cavity through the glass observation window fixing plate.

3. The sub-micron microfluidic experimental device under high temperature and high pressure conditions according to claim 2, wherein The distance between the glass observation window and the microscopic chip does not exceed 0.1 mm.

4. The sub-micron microfluidic experimental device under high temperature and high pressure conditions according to claim 1, wherein Water circulation rotating blades are arranged on the outer wall surface of the rotating bearing. When the rotating bearing operates, the water circulation rotating blades rotate around the central axis of the microscopic observation port to accelerate the water circulation flow rate.

5. The sub-micron microfluidic experimental device under high temperature and high pressure conditions according to claim 1, characterized in that, It also includes a first intermediate container, a second intermediate container, a double-cylinder displacement pump, and a fluid metering container. The first intermediate container and the second intermediate container are respectively assembled on the double-cylinder displacement pump. The first intermediate container and the second intermediate container are respectively connected to the displacement inlet through pipelines. The fluid metering container is connected to the displacement outlet through a pipeline.

6. A method for using a sub-micron microfluidic experimental device under high temperature and high pressure conditions as described in claim 5, characterized in that, The usage method includes: Assembling a sub-micron scale microfluidic experimental device under high temperature and high pressure conditions; Embed the objective lens waterproof thin sheet on the inner lens of the objective lens of the microscope; place the objective lens into the microscopic observation port, turn on the heating controller, and set it to the constant temperature mode to heat the chamber body of the observation device to the target temperature T; after reaching the target temperature T, turn on the water circulation temperature detection and flow rate controller and the water cooling device, control the rotation speed of the water circulation rotating blade and monitor the water temperature at the outlet of the water cooling cycle in real time to ensure that the water temperature is maintained under the temperature that the objective lens of the microscope can withstand; Turn on the confining pressure pump and slowly inject hydraulic oil into the chamber body of the observation device until there are no bubbles at the confining pressure outlet, then plug the confining pressure outlet and turn on the constant pressure mode of the confining pressure pump to make the hydraulic oil fill the space between the microchip and the glass observation window through the hydraulic oil port, so that the upper and lower sides of the microchip maintain a constant confining pressure of the first pressure P1; Adjust the height of the objective lens for focusing until the microscopic structure inside the microchip is clearly observed; Open the switch of the first intermediate container filled with water, turn on the double-cylinder displacement pump, saturate the microchip with water, observe the migration of the water phase in the microchip, maintain the internal pressure of the microscopic model at the second pressure P2, and after saturation with water is completed, close the displacement inlet; Open the switch of the second intermediate container filled with gas, turn on the double-cylinder displacement pump, increase the pressure of the gas to the third pressure P3, P3 > P2; open the displacement inlet, inject gas into the microchip, and at the same time open the displacement outlet, and observe and record the seepage process of gas and water in the microchip through the microscope.

7. The usage method according to claim 6, characterized in that, Assemble the sub-micron microfluidic experimental device under high temperature and high pressure conditions in the following way: Place the microchip on the microchip fixing plate and fix it on the microchip clamping plate with fixing bolts to obtain the microchip fixture; hermetically assemble the microchip fixture into the inlet on the side wall of the chamber body of the observation device; Fix the upper cover of the chamber body on the chamber body of the observation device with bolts; place the glass observation window on the sapphire glass observation window fixing plate and fix it at the bottom of the water circulation cavity with bolts; screw the water circulation cavity into the hole in the middle of the upper cover of the chamber body through threads and rubber sealing rings; screw the microscopic observation port into the inside of the water circulation cavity through threads; After wrapping the heating and insulation sleeve around the chamber body of the observation device, connect it to the heating controller through wires; connect the confining pressure pump to the confining pressure inlet on the upper cover of the chamber body through pipelines; connect the water circulation temperature detection and flow rate controller to the water cooling cycle outlet and the water cooling device on the water circulation cavity through pipelines respectively; connect the water cooling device to the water cooling cycle inlet on the water circulation cavity through pipelines; connect the double-cylinder displacement pump to the first intermediate container filled with water and the second intermediate container filled with gas through pipelines respectively; connect the first intermediate container and the second intermediate container to the displacement inlet on the microchip fixture; Connect the vacuum pump to the displacement outlet on the microchip fixture, turn on the vacuum pump, extract the air in the microchip, then close the outlet switch and connect the fluid metering container.

8. The method of use according to claim 7, characterized in that After observing and recording the seepage process of gas and water in the microchip through the microscope, the usage method further includes the step of ending the experiment, and the step of ending the experiment includes: Turn off the double-cylinder displacement pump and stop heating. After the temperature reaches room temperature, turn off the confining pressure pump. After unloading the confining pressure, turn off the water circulation temperature detection and flow rate controller and the water cooling device, and then clean.

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