A real carbonate rock microfluidic chip and its fabrication method

Abstract

This invention belongs to the field of microfluidic chip technology, disclosing a realistic carbonate rock microfluidic chip and its preparation method. The method involves pouring an adhesive into grooves on a transparent substrate, placing a core sheet on the uncured adhesive surface within the grooves, and grinding the core sheet surface after the adhesive has cured. Then, a laser is used to pattern the core sheet surface, etching out realistic pore channel images, liquid injection channels, and liquid outflow channels. A PDMS film is then coated onto the surface of the semi-finished carbonate rock microfluidic chip. A transparent cover is placed over the PDMS film, and the transparent substrate, PDMS film, and cover are fixedly connected. Both the cover and the PDMS film have liquid inlets and outlets at positions corresponding to the liquid injection and outflow channels. This invention can reproduce the realistic pore channel structure in the microfluidic chip while simultaneously reproducing the mineral characteristics of the real strata, ensuring that its visibility is not affected.

Description

Technical Field

[0001] This invention belongs to the field of microfluidic chip technology, and in particular to a real carbonate rock microfluidic chip and its preparation method. Background Technology

[0002] Microfluidics, as an emerging experimental method, has been widely applied in fields such as chemistry, biology, and materials science. Its main advantages lie in its ability to control and observe fluid behavior at the microscale, offering high resolution, high precision, and high flexibility. However, applying microfluidics to geological and petroleum engineering, especially to simulate the pore structure of real rocks, such as carbonate rocks, still faces many challenges. Currently, existing microfluidic chip materials cannot fully simulate the complex pore structures and fluid behaviors in real geological environments, limiting the accuracy and reliability of experimental results. Therefore, a key issue is how to reproduce the real pore channel structure and mineral characteristics of real strata in a microfluidic chip while ensuring its visibility remains unaffected. Summary of the Invention

[0003] To address the current limitations of microfluidic chips in realistically simulating the mineral characteristics of geological formations, this invention aims to provide a realistic carbonate rock microfluidic chip and its preparation method. This invention can reproduce the real pore channel structure in the microfluidic chip while simultaneously reproducing the mineral characteristics of the real geological formation, ensuring that its visibility remains unaffected.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for fabricating a real carbonate rock microfluidic chip includes the following steps:

[0006] Adhesive is poured into the grooves on the prepared transparent substrate, and then a core sheet is placed on the uncured adhesive surface in the groove. After the adhesive cures, the surface of the core sheet is ground, and then patterned on the surface of the core sheet using a laser to etch out real pore channel images, liquid injection channels, and liquid outflow channels, obtaining a semi-finished carbonate rock microfluidic chip. A PDMS film is then covered on the surface of the semi-finished carbonate rock microfluidic chip. A prepared transparent cover is then placed on the surface of the PDMS film, and the transparent substrate, PDMS film, and transparent cover are fixedly connected to obtain the real carbonate rock microfluidic chip. Liquid inlets and liquid outlets are opened on both the transparent cover and the PDMS film at positions corresponding to the liquid injection channels and liquid outflow channels.

[0007] Preferably, the radial dimension of the core slice is smaller than the radial dimension of the groove, and the thickness of the core slice is greater than or equal to the depth of the groove, with a depth difference of 0~0.5mm.

[0008] Preferably, the core slice is rectangular in shape, and the groove is rectangular in shape; the length of the core slice is 0.5-1 mm shorter than the length of the groove, and the width of the core slice is 0.5-1 mm shorter than the width of the groove; the thickness of the core slice is 200-500 µm, and the depth of the groove is 200-500 µm.

[0009] Preferably, when pouring the adhesive into the groove on the transparent substrate, the adhesive completely fills the groove.

[0010] Preferably, the adhesive is epoxy glue or UV glue.

[0011] Preferably, after grinding the surface of the core sheet, the surface of the core sheet is flush with the surface of the transparent substrate and the surface is flat and smooth.

[0012] Preferably, the real pore channel image is obtained by digital image processing after CT scanning of the real rock core.

[0013] Preferably, the thickness of the PDMS film is 0.5-1.0 mm.

[0014] Preferably, the carbonate rock is selected from dolomite or marble.

[0015] Preferably, the transparent substrate, PDMS film and transparent cover are fixedly connected at the four corners to form an integrated structure by screws.

[0016] The present invention also provides a real carbonate rock microfluidic chip, which is prepared by the above-described preparation method of the present invention.

[0017] The present invention has the following beneficial effects:

[0018] The significant advantage of this invention lies in etching real pore channels onto the rock core, which both simulates real pore channels and preserves the real geological environment, while ensuring the visualization of the experimental process. By etching real pore channels onto thin sections of real rock cores to simulate the real geological environment, and combining this with the use of transparent materials, real-time observation and precise control of the fluid flow process are achieved. This not only improves the accuracy and reliability of the experiment, but also simplifies the fabrication process, reduces experimental costs, and demonstrates a simple and ingenious principle. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a real carbonate rock microfluidic chip base (i.e., a transparent substrate) in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a semi-finished carbonate rock microfluidic chip in an embodiment of the present invention;

[0021] Figure 3This is a schematic diagram of the overall structure of the microfluidic chip based on real carbonate rock in an embodiment of the present invention;

[0022] Figure 4 This is a physical image of the actual carbonate rock microfluidic chip obtained in Example 2 of the present invention.

[0023] In the figure, 1-transparent substrate, 2-groove, 3-core sheet, 4-bolt, 5-transparent cover, 6-PDMS film, 7-threaded hole. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified or conflicting, the preferred embodiments can be combined arbitrarily.

[0025] See Figures 1-4 The microfluidic chip based on real carbonate rock provided by this invention includes two rectangular flat molds (including a transparent substrate 1 and a transparent cover 5), a carbonate rock core sheet, an adhesive, a PDMS film, and bolts. The rectangular flat molds can be made of transparent materials such as PMMA, PC, or glass, with a thickness of 2-4 mm. The carbonate rock is dolomite or marble. The core sheet 3 has a thickness of 200-500 µm, and its length and width are 0.5-1 mm smaller than the size of the groove 2. The thickness must be greater than or equal to the depth of the groove 2. The surface of the core sheet 3 is polished smooth with a grinder. The adhesive can be epoxy glue or UV glue. The PDMS film 6 has a thickness of 0.5-1 mm.

[0026] The principle of this invention is as follows: This invention etches a realistic pore structure onto a carbonate rock core thin section, simulating not only the pore structure of the actual strata in the pore channels but also the real geological environment of the strata, making the experimental results closer to reality. Furthermore, utilizing the viscoelasticity of the PDMS film 6, it can perfectly adhere to the upper surface of the etched core thin section 3. The viscoelasticity of the PDMS film 6 also acts as a gasket between the two transparent rectangular flat molds sealing the chip, and the light transmittance of the PDMS film 6 ensures the chip's visibility. This invention can reproduce realistic geological environments and pore structures on a microfluidic chip and maintain good visualization during experiments.

[0027] The specific steps of the fabrication method of the microfluidic chip based on real carbonate rock in this invention are as follows:

[0028] Drill a threaded hole at each of the four corners of two identical rectangular flat molds. One mold serves as the transparent substrate 1, and the other as the transparent cover 5. The thickness of the rectangular flat molds (i.e., transparent substrate 1 and transparent cover 5) is 2-4 mm, and the material can be transparent materials such as PMMA, PC, or glass. The positions of the threaded holes on the two rectangular flat molds must be exactly the same. Then, use a laser marking machine to mark one side of the transparent substrate 1 (e.g., ...). Figure 1 A groove 2 is cut into the upper surface (as shown), located in the middle of the transparent substrate 1, with a depth of 200-500 µm, to obtain a real carbonate rock microfluidic chip base. A carbonate rock core is selected and sliced ​​to form a carbonate rock core slice 3. The carbonate rock is selected from dolomite or calcite. The core slice 3 has a thickness of 200-500 µm, and its length and width are 0.5-1 mm smaller than the corresponding dimensions of the groove 2. The thickness of the core slice 3 must be greater than or equal to the depth of the groove 2. The surface of the core slice 3 is polished smooth using a grinder. Adhesive is poured into the groove 2 of the real carbonate rock microfluidic chip base, completely filling the groove 2. The adhesive can be epoxy or UV adhesive. The core slice 3 is placed into the groove 2 of the core microfluidic chip base. After the adhesive cures, the surface of the core slice 3 is finely surface-treated using a grinder to obtain a real carbonate rock microfluidic chip substrate. The adhesive must be free of air bubbles after curing. A laser marking machine is used on the real carbonate rock microfluidic chip base. Real pore channels and liquid injection / outflow channels are etched onto a core slice 3 on a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image is obtained by digital image processing after CT scanning of a real core. A PDMS film 6 of the same size as a rectangular flat mold is taken, and holes are drilled on the PDMS film 6 at the same locations as the rectangular flat mold. Inlet and outlet ports are also drilled on the PDMS film 6 for liquid entry and exit. The thickness of the PDMS film 6 is 0.5-1 mm. mm, the inlet and outlet positions on the PDMS film 6 must correspond to the liquid injection and outflow channels on the core thin film 3; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring that the holes are aligned, and ensure that there are no air bubbles after covering with the PDMS film 6; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring that the holes are aligned; use a laser marking machine to make holes again on the transparent cover sheet 5 for liquid injection and outflow, and the hole positions of the transparent cover sheet 5 when making holes again must be consistent with the inlet and outlet positions of the PDMS film 6; use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, and finally obtain the real carbonate rock microfluidic chip.

[0029] Compared with existing technologies, the significant advantage of this invention lies in etching real geological pore channels onto thin sections of real carbonate rock cores, which not only ensures the authenticity of the geological environment and pore structure but also preserves the visualization of the experimental process. Furthermore, because the chip uses real geological core material, the experimental results will be more realistic and reliable.

[0030] Example 1

[0031] In this embodiment, a threaded hole is drilled at each of the four corners of two rectangular glass plates, each 60×15mm in length and width. One plate serves as a transparent substrate 1, and the other as a transparent cover plate 5. The thickness of the glass plates is 2mm, and the threaded holes on both glass plates are positioned identically. Then, a rectangular groove 2 is laser-marked on one side of the transparent substrate 1. The groove 2 is located in the center of the transparent substrate 1, and its length and width are parallel to those of the transparent substrate 1. The groove 2 has a length and width of 30×10mm and a depth of 200µm, resulting in a real carbonate rock microfluidic chip base. Dolomite is selected and sliced ​​to form rectangular dolomite core sections 3 with a thickness of 200µm. The core slice 3 has dimensions of 29.5 × 9.5 mm. The surface of the core slice 3 is polished smooth using a grinder. Adhesive (epoxy resin) is poured into the groove 2 of the real carbonate rock microfluidic chip base, ensuring the groove is completely filled. The core slice 3 is then placed into the groove 2 of the microfluidic chip base. After the adhesive cures, the surface of the core slice 3 is finely surface-treated using a grinder to obtain the real carbonate rock microfluidic chip substrate. No air bubbles are present after the adhesive cures. Laser marking is then applied. The machine etches real pore channels and liquid injection and outflow channels on a core slice 3 of a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image is obtained by digital image processing after CT scanning of the real rock core. A PDMS film 6 with a size of 60×15mm is taken, and holes are drilled on the PDMS film 6 at the same drilling positions as the rectangular flat plate mold. Inlet and outlet ports are also drilled on the PDMS film 6 for liquid inflow and outflow. The thickness of the PDMS film 6 is 0.5 mm. mm, the inlet and outlet positions on the PDMS film 6 correspond to the liquid injection and outflow channels on the core thin section; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring the hole positions are aligned, and there should be no air bubbles after the PDMS film 6 is covered; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring the hole positions are aligned; use a laser marking machine to make holes again on the transparent cover sheet 5 for liquid injection and outflow, the hole positions of the transparent cover sheet 5 when making holes again are consistent with the inlet and outlet positions on the PDMS film 6, and then use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, finally obtaining the real carbonate rock microfluidic chip.

[0032] Figure 1This is a schematic diagram of the actual carbonate rock microfluidic chip base in this embodiment. It can be seen that a threaded hole 7 is drilled at each of the four corners of the glass substrate, which is combined with the transparent cover 5 for chip encapsulation. A groove 2 is opened in the middle of the transparent substrate 1, and the groove 2 is used to place the core slice 3. Figure 2 This is a schematic diagram of the semi-finished carbonate rock microfluidic chip in this embodiment. It can be seen that the core sheet 3 has been fixed in the groove 2 of the glass substrate, and real stratum pore channels and liquid inlet / outlet channels have been etched on the core sheet 3. The carbonate rock microfluidic chip has been initially formed.

[0033] Example 2

[0034] In this embodiment, a threaded hole is drilled at each of the four corners of two rectangular PMMA plates, each 70×15mm in length and width. One plate serves as the transparent substrate 1, and the other as the transparent cover plate 5. The PMMA plates are 4mm thick, and the threaded holes on both plates are aligned. Then, a rectangular groove 2 is laser-marked on one side of the transparent substrate 1, positioned in the center. The length and width of the groove 2 are parallel to those of the transparent substrate 1. The groove 2 is 40×10mm in length and width and 500µm deep, resulting in a real carbonate rock microfluidic chip base. Calcite is then sliced ​​to form rectangular calcite core sections 3, each 500µm thick. The core slice 3 has dimensions of 29×9mm. The core slice 3 is polished smooth using a grinder. Adhesive is poured into the groove 2 of the real carbonate rock microfluidic chip base, ensuring the groove is completely filled. The adhesive is a UV adhesive. The core slice 3 is placed in the groove 2 of the microfluidic chip base and irradiated with a UV lamp. After the adhesive cures, the surface of the core slice 3 is finely surface-treated using a grinder to obtain the real carbonate rock microfluidic chip substrate. No air bubbles are present after the adhesive cures. Laser processing is then used to... A standard etching machine etched real pore channels and liquid injection and outflow channels on a core slice 3 of a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image was obtained by digital image processing after CT scanning of the real core. A PDMS film 6 with a size of 70×15mm was taken, and holes were drilled on the PDMS film 6 at the same drilling positions as the rectangular flat plate mold. Inlet and outlet ports were also drilled on the PDMS film 6 for liquid inflow and outflow. The thickness of the PDMS film 6 was 1. mm, the inlet and outlet positions on the PDMS film 6 correspond to the liquid injection and outflow channels on the core thin section 3; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring that the holes are aligned and that there are no air bubbles after the PDMS film 6 is covered; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring that the holes are aligned; use a laser marking machine to make holes again on the transparent cover sheet 5 for liquid injection and outflow, and when the transparent cover sheet 5 is made again, the hole positions are consistent with the inlet and outlet positions on the PDMS film 6; use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, and finally obtain the real carbonate rock microfluidic chip.

[0035] Figure 3 This is a schematic diagram of the overall structure of the microfluidic chip based on real carbonate rock in this embodiment. It can be seen that the transparent substrate 1 is at the bottom. After the real rock core (i.e., the rock core sheet 3) is bonded to the groove 2 on the transparent substrate 1, the real rock core pore channels are etched on the surface of the rock core sheet 3 with a laser. Then, the PDMS film 6 is covered, and finally the transparent cover 5 is covered and the transparent substrate 1 and the transparent cover 5 are fixed with bolts to obtain the real carbonate rock microfluidic chip.

[0036] Example 3

[0037] In this embodiment, a threaded hole is drilled at each of the four corners of two rectangular PMMA plates with dimensions of 80×15mm. One plate serves as a transparent substrate, and the other as a transparent cover plate 5. The PMMA plates are 3mm thick, and the threaded holes on both PMMA plates are positioned identically. Then, a groove 2 is laser-marked on one side of the transparent substrate 1, located in the center of the substrate 1. The length and width of the groove 2 are parallel to the length and width of the transparent substrate 1. The groove 2 has dimensions of 40×10mm and a depth of 400µm, resulting in a real carbonate rock microfluidic chip base. A rock core is selected and sliced ​​to form a rectangular core slice 3 with a thickness of 500µm. The core slice 3, with dimensions of µm and length and width of 29×9mm, was polished smooth using a grinder. Adhesive, specifically UV adhesive, was poured into the groove of the real carbonate rock microfluidic chip base, ensuring complete coverage of the groove. The core slice 3 was then placed into the groove of the microfluidic chip base and irradiated with a UV lamp. After the adhesive cured, the surface of the core slice 3 was finely surface-treated using a grinder to obtain the real carbonate rock microfluidic chip substrate. No air bubbles were observed after the adhesive cured. Laser marking was then applied to the real carbonate rock microfluidic chip substrate. Real pore channels and liquid injection and outflow channels were etched onto a core slice 3 on a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image was obtained by digital image processing after CT scanning of the real core. A PDMS film 6 with a size of 80×15mm was taken, and holes were drilled on the PDMS film 6 at the same drilling positions as the rectangular flat plate mold. Inlet and outlet ports were also drilled on the PDMS film 6 for liquid entry and exit. The thickness of the PDMS film 6 was 0.8 mm. mm, the inlet and outlet positions on the PDMS film 6 correspond to the liquid injection and outflow channels on the core thin section 3; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring the hole positions are aligned, and ensure there are no air bubbles after covering with the PDMS film 6; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring the hole positions are aligned; use a laser marking machine to make holes again on the transparent cover sheet for liquid injection and outflow, the hole positions of the transparent cover sheet 5 when making holes again are consistent with the inlet and outlet positions of the PDMS film 6, use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, and finally obtain the real carbonate rock microfluidic chip.

[0038] Example 4

[0039] In this embodiment, a threaded hole is drilled at each of the four corners of two rectangular PMMA plates, each 60×15mm in length and width. One plate serves as a transparent substrate, and the other as a transparent cover plate 5. The PMMA plates are 3mm thick, and the threaded holes on both plates are aligned. Then, a groove 2 is laser-marked on one side of the transparent substrate 1, located in the center of the substrate 1. The length and width of the groove 2 are parallel to those of the transparent substrate 1. The groove 2 is 30×10mm in length and width and 300µm deep, thus obtaining a real carbonate rock microfluidic chip base. A rock core is selected and sliced ​​to form a rectangular core slice 3, with a thickness of 400µm. The core slice 3, measuring 29.2 × 9.2 mm in length and width, was polished smooth using a grinder. Adhesive (UV adhesive) was poured into the groove of the real carbonate rock microfluidic chip base, ensuring the groove was completely filled. The core slice 3 was then placed into the groove of the microfluidic chip base and irradiated with UV light. After the adhesive cured, the surface of the core slice 3 was finely surface-treated using a grinder to obtain the real carbonate rock microfluidic chip substrate. No air bubbles were observed after the adhesive cured. A laser marking machine was then used. Real pore channels and liquid injection and outflow channels were etched onto a core slice 3 on a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image was obtained by digital image processing after CT scanning of the real core. A PDMS film 6 with a size of 60×15mm was taken, and holes were drilled on the PDMS film 6 at the same drilling positions as the rectangular flat plate mold. Inlet and outlet ports were also drilled on the PDMS film 6 for liquid inflow and outflow. The thickness of the PDMS film 6 was 0.6 mm. mm, the inlet and outlet positions on the PDMS film 6 correspond to the liquid injection and outflow channels on the core thin section 3; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring the hole positions are aligned, and ensure there are no air bubbles after covering with the PDMS film 6; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring the hole positions are aligned; use a laser marking machine to make holes again on the transparent cover sheet for liquid injection and outflow, the hole positions of the transparent cover sheet 5 when making holes again are consistent with the inlet and outlet positions of the PDMS film 6, use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, and finally obtain the real carbonate rock microfluidic chip.

[0040] Example 5

[0041] In this embodiment, a threaded hole is drilled at each of the four corners of two rectangular PMMA plates, each 60×15mm in length and width. One plate serves as a transparent substrate, and the other as a transparent cover plate 5. The PMMA plates are 3mm thick, and the threaded holes on both plates are aligned. Then, a groove 2 is laser-marked on one side of the transparent substrate 1, positioned in the center. The length and width of the groove 2 are parallel to those of the transparent substrate 1. The groove 2 is 30×10mm in length and width and 200µm deep, resulting in a real carbonate rock microfluidic chip base. A rock core is selected and sliced ​​to form a rectangular core slice 3, with a thickness of 350µm. The core slice 3, measuring 29.1 × 9.1 mm in length and width, was polished smooth using a grinder. Adhesive (UV adhesive) was poured into the groove of the real carbonate rock microfluidic chip base, ensuring the groove was completely filled. The core slice 3 was then placed into the groove of the microfluidic chip base and irradiated with UV light. After the adhesive cured, the surface of the core slice 3 was finely surface-treated using a grinder to obtain the real carbonate rock microfluidic chip substrate. No air bubbles were observed after the adhesive cured. A laser marking machine was then used. Real pore channels and liquid injection and outflow channels were etched onto a core slice 3 on a real carbonate rock microfluidic chip substrate to obtain a semi-finished carbonate rock microfluidic chip. The real pore channel image was obtained by digital image processing after CT scanning of the real core. A PDMS film 6 with a size of 60×15mm was taken, and holes were drilled on the PDMS film 6 at the same drilling positions as the rectangular flat plate mold. Inlet and outlet ports were also drilled on the PDMS film 6 for liquid entry and exit. The thickness of the PDMS film 6 was 0.5 mm. mm, the inlet and outlet positions on the PDMS film 6 correspond to the liquid injection and outflow channels on the core thin section 3; cover the obtained semi-finished carbonate rock microfluidic chip with the perforated PDMS film 6, ensuring the hole positions are aligned, and ensure there are no air bubbles after covering with the PDMS film 6; then cover the PDMS film 6 with the transparent cover sheet 5, ensuring the hole positions are aligned; use a laser marking machine to make holes again on the transparent cover sheet for liquid injection and outflow, the hole positions of the transparent cover sheet 5 when making holes again are consistent with the inlet and outlet positions of the PDMS film 6, use bolts to fix the four corners of the transparent substrate 1 and the transparent cover sheet 5, and finally obtain the real carbonate rock microfluidic chip.

[0042] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A method for fabricating a real carbonate rock microfluidic chip, characterized in that, The process includes the following: Adhesive is poured into the groove (2) on the prepared transparent substrate (1), and then the core sheet (3) is placed on the uncured adhesive surface in the groove (2). After the adhesive is cured, the surface of the core sheet (3) is ground, and then patterned on the surface of the core sheet (3) using a laser to etch out the real pore channel image, liquid injection channel and liquid outflow channel, and obtain a semi-finished carbonate rock microfluidic chip. A PDMS film (6) is then covered on the surface of the semi-finished carbonate rock microfluidic chip. The prepared transparent cover (5) is then covered on the surface of the PDMS film (6), and the transparent substrate (1), PDMS film (6) and transparent cover (5) are fixedly connected to obtain the real carbonate rock microfluidic chip. The transparent cover (5) and PDMS film (6) are provided with liquid inlet and liquid outlet at positions corresponding to the liquid injection channel and liquid outflow channel, respectively.

2. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, The radial dimension of the core section (3) is smaller than the radial dimension of the groove (2), and the thickness of the core section (3) is greater than or equal to the depth of the groove (2), with a depth difference of 0~0.5mm.

3. The method for preparing a real carbonate rock microfluidic chip according to claim 2, characterized in that, The core section (3) is rectangular in shape, and the groove (2) is rectangular in shape; the length of the core section (3) is 0.5-1 mm shorter than the length of the groove (2), and the width of the core section (3) is 0.5-1 mm shorter than the width of the groove (2); the thickness of the core section (3) is 200-500 µm, and the depth of the groove (2) is 200-500 µm.

4. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, When pouring adhesive into the groove (2) on the transparent substrate (1), the adhesive should completely fill the groove (2); the adhesive is epoxy glue or UV glue.

5. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, After grinding the surface of the core sheet (3), the surfaces of the core sheet (3) and the transparent substrate (1) are flush and smooth.

6. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, The real pore channel image is obtained by digital image processing after CT scanning of the real rock core.

7. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, The thickness of the PDMS film (6) is 0.5-1.0 mm.

8. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, Carbonate rocks are selected from dolomite or marble.

9. The method for preparing a real carbonate rock microfluidic chip according to claim 1, characterized in that, The four corners of the transparent substrate (1), PDMS film (6) and transparent cover (5) are fixed together as a whole by screws.

10. A real carbonate rock microfluidic chip, characterized in that, The real carbonate rock microfluidic chip is prepared by any one of the preparation methods of claims 1 to 9.

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