Microscopic oil displacement wave and coefficient determination method

Abstract

The invention discloses a microscopic oil displacement wave and coefficient determination method which comprises the following steps: by taking a pore throat identification result of a rock sample casting body slice picture as a reference, manufacturing a chip by utilizing a micro-fluidic material; carrying out an oil displacement experiment on the chip through an oil displacement medium by utilizing a micro-fluidic experimental device to obtain microscopic images before and after oil displacement; performing segmentation processing on the microscopic images before and after oil displacement to obtain a pore throat distribution area and a displacement area of an oil displacement medium in the pore throat distribution area; dividing the pore throat distribution area into a plurality of circular areas according to the principle of maximum quantity and maximum area; and determining the displaced circular area at the circle center as a swept circular area, and determining swept coefficients according to the area of the swept circular area. According to the method, on the basis of defining the judgment standard of the affected area, the residual oil utilization characteristics are quantitatively represented through the sweep coefficient by utilizing the microfluidic technology, and the method has important significance on the research of improving the recovery ratio in the high water cut period; in addition, the method can realize fine calculation of sweep coefficients under different pore throat radiuses.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation, and particularly relates to a method for determining the microscopic oil displacement sweep efficiency. Background Art

[0002] At present, the major domestic oilfields have basically entered the high water cut development stage, and it is becoming increasingly difficult to mobilize the remaining oil and improve the recovery efficiency. The oil recovery factor is equal to the sweep efficiency multiplied by the oil displacement efficiency. There are two ways to improve the recovery efficiency. One is to increase the sweep efficiency, and the other is to increase the oil displacement efficiency. Therefore, accurately calculating the sweep efficiency and oil displacement efficiency of a certain displacement medium plays an important role in the research of improving the recovery efficiency.

[0003] There are many calculation methods for the sweep efficiency in the research of macroscopic remaining oil. For example, using numerical simulation methods, by calculating the grid volume swept by the displacement medium divided by the total grid volume of the reservoir, the sweep efficiency can be calculated; the planar sweep efficiency can be calculated through saturation point monitoring in core flooding experiments. In the research of microscopic remaining oil, the calculation methods for the sweep efficiency mainly calculate the sweep efficiency through the number of pixels occupied by crude oil, the number of pixels occupied by the rock skeleton and the pores not swept, and the porosity (Liu Xiaoling), and calculate the sweep efficiency according to the difference in the chromaticity of oil and water during the displacement process (Yang Zhenya, etc.). Summary of the Invention

[0004] The inventors found that the existing calculation methods for the sweep efficiency in the research of microscopic remaining oil have not achieved fine calculation of the sweep efficiency under different pore throat radii. In order to enrich the process route and increase the selection space, the embodiments of the present invention provide a method for determining the microscopic oil displacement sweep efficiency. On the basis of defining the judgment standard for the swept pore throats, using microfluidic technology, the characteristics of remaining oil mobilization are evaluated by quantitatively characterizing the sweep efficiency; in addition, this method can achieve fine calculation of the sweep efficiency under different pore throat radii.

[0005] The embodiments of the present invention provide a method for determining the microscopic oil displacement sweep efficiency, including:

[0006] Taking the pore throat identification result of the thin section of the rock sample casting as a reference, making a chip using microfluidic materials;

[0007] Using a microfluidic experimental device, performing an oil displacement experiment on the chip with a displacement medium to obtain microscopic images before and after oil displacement;

[0008] Performing segmentation processing on the microscopic images before and after oil displacement respectively to obtain the pore throat distribution area and the displacement area of the displacement medium therein;

[0009] Dividing the pore throat distribution area into multiple circular areas according to the principles of the largest number and the largest area;

[0010] Determine the circular area displaced at the center of the circle as the affected circular area, and determine the sweep coefficient according to the area of the affected circular area.

[0011] The beneficial effects of the above technical solutions provided by the embodiments of the present invention at least include:

[0012] (1) The microscopic oil displacement sweep coefficient determination method provided by the embodiments of the present invention pre-defines the judgment criterion for the affected area as the displacement of crude oil at the center of the circle; on this basis, microscopic images before and after oil displacement are obtained using microfluidic technology, and the pore-throat distribution area and the displacement area of the displacement medium therein are obtained through segmentation processing, thereby realizing the characterization of the sweep characteristics at the level of the segmented circle in the pore throat microscopically; quantitatively characterizing the remaining oil production characteristics through the sweep coefficient is of great significance for the study of improving oil recovery in the high water cut period; in addition, this method can realize the fine calculation of the sweep coefficient at different pore throat radii.

[0013] (2) The microscopic oil displacement sweep coefficient determination method provided by the embodiments of the present invention uses microfluidic materials to make a chip and uses a microfluidic experimental device to perform an oil displacement experiment on the chip. Since the microfluidic material is a transparent material, the displacement process and displacement effect can be directly observed through a microscope during the experiment.

[0014] (3) The microscopic oil displacement sweep coefficient determination method provided by the embodiments of the present invention draws a bar chart of the sweep degree. The abscissa in the bar chart is the radius interval, and the ordinate is the sweep frequency and the sweep coefficient. The sweep frequency is used to characterize the total number of circular areas and the number of affected circular areas in each radius interval, and the sweep coefficient is used to characterize the sweep coefficient in each radius interval. The remaining oil production situation in each radius interval can be intuitively displayed through the columnar body.

[0015] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the written specification, claims, and drawings.

[0016] The technical solutions of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0017] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0018] Figure 1 It is the flowchart of the microscopic oil displacement sweep coefficient determination method in Embodiment 1 of the present invention;

[0019] Figure 2It is the microscopic image of a casting thin slice in the first embodiment of the present invention;

[0020] Figure 3 It is for Figure 1 the microfluidic chip fabricated from the casting thin slice in

[0021] Figure 4 It is the pore-throat wave propagation discrimination method in the first embodiment of the present invention;

[0022] Figure 5 It is the pore-throat skeleton recognition diagram in the first embodiment of the present invention;

[0023] Figure 6 It is the column chart of water flooding pore-throat wave propagation degree in the first embodiment of the present invention;

[0024] Figure 7 It is the pore-throat utilization distribution diagram in the first embodiment of the present invention;

[0025] Figure 8 It is the microfluidic experimental device diagram in the second embodiment of the present invention;

[0026] Figure 9 It is the column chart of polymer flooding pore-throat wave propagation degree in the second embodiment of the present invention;

[0027] Figure 10 It is the column chart of polymer / surfactant binary flooding pore-throat wave propagation degree in the second embodiment of the present invention;

[0028] Figure 11 It is the column chart of polymer / surfactant / alkali ternary composite flooding pore-throat wave propagation degree in the second embodiment of the present invention. Detailed implementation manners

[0029] Hereinafter, the exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0030] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Although the present invention only describes the preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0031] In the description of the present invention, it should be noted that terms such as "comprising", "including", "having", "containing", etc. are all open-ended terms, meaning including but not limited to.

[0032] Microfluidics is a multidisciplinary research field that has developed rapidly since the 1990s. The precise control of fluids at the microscale makes it very suitable for studying the mechanisms of enhanced oil recovery with different displacement media. The present invention uses a microfluidic model to simulate oil displacement experiments, and studies the microscopic remaining oil distribution state during the dynamic displacement process, as well as the initiation and mobilization laws of the microscopic remaining oil by the displacement system by calculating the microscopic oil displacement sweep coefficient.

[0033] The embodiment of the present invention provides a method for determining the microscopic oil displacement sweep coefficient. Based on the definition of the judgment standard for the swept area, using microfluidic technology, the remaining oil mobilization characteristics are quantitatively characterized by the sweep coefficient, which is of great significance for the study of enhanced oil recovery in the high water cut period; in addition, this method can achieve the precise calculation of the sweep coefficient under different pore throat radii.

[0034] Embodiment 1

[0035] Embodiment 1 of the present invention provides a method for determining the microscopic oil displacement sweep coefficient. Referring to Figure 1 shown, the method includes the following steps:

[0036] Step S11: Based on the pore throat recognition result of the thin section of the rock sample cast, a chip is made using microfluidic materials.

[0037] Perform image recognition and analysis on the pore structure in the thin section of the rock sample cast, select the classic pore throat characteristics among them, scale them according to the same size, and after appropriate adjustment, select a suitable microfluidic material to make a chip. Refer to Figure 2 and Figure 3 shown, which are respectively the microscopic image of the thin section of the cast and the chip made of microfluidic materials according to the pore throat recognition result of the image.

[0038] Step S12: Using a microfluidic experimental device, perform an oil displacement experiment on the chip with the displacement medium to obtain the microscopic images before and after oil displacement.

[0039] Connect the chip to the microfluidic experimental device to simulate microscopic oil displacement. Take the global map of the microfluidic chip under the microscope (at the same magnification) at the beginning and end of the displacement respectively, record the crude oil distribution, and complete the acquisition of the microscopic images before and after oil displacement.

[0040] Step S13: Perform segmentation processing on the microscopic images before and after oil displacement respectively to obtain the pore throat distribution area and the displacement area of the displacement medium therein.

[0041] Use professional image - processing software to perform image enhancement processing on the microscopic images taken in the experiment, then set specific parameter values for color - block division, and further segment the image to obtain the pore - throat distribution area and the displacement area of the displacement medium therein.

[0042] Specifically, segment the microscopic image before oil displacement to obtain the pore - throat distribution area and the crude - oil distribution area therein; segment the microscopic image after oil displacement to obtain the remaining - oil distribution area, and through the comparison between the remaining - oil distribution area and the crude - oil distribution area, obtain the displacement area of the displacement medium.

[0043] Step S14: Segment the pore - throat distribution area into multiple circular areas according to the principles of the largest number and the largest area.

[0044] The largest area means that the segmented circles are tangent to the boundary of the pore - throat as much as possible; the largest number means that the segmented circles are arranged tangent to each other as much as possible, that is, the number of arranged circles is the largest.

[0045] The segmentation of the pore - throat realizes a more fine - grained characterization of displacement characteristics.

[0046] Step S15: Determine the circular area displaced at the center of the circle as the affected circular area, and determine the sweep efficiency according to the area of the affected circular area.

[0047] The degree of pore - throat sweep is closely related to the pore - throat radius. When the oil in the central axis area of the pore - throat is displaced, it can be determined that the "pore - throat is swept", as shown in Figure 4 shown. That is, determine the circular area where the crude oil at the center of the circle is displaced by the displacement medium as the affected circular area.

[0048] According to the judgment standard of area sweep, extract the central - axis skeleton. Specifically, segment the pore - throat distribution area into multiple circular areas according to the principles of the largest number and the largest area, as shown in Figure 5 shown.

[0049] On the basis of pore - throat identification and segmentation and the determination of the affected circular area, determine the sweep efficiency according to the area of the affected circular area. The sweep efficiency can reflect the utilization situation of the remaining oil in the pore - throat.

[0050] Specifically, the determination of the sweep efficiency includes performing at least one of the following:

[0051] Determine the ratio of the sum of the areas of all affected circular areas to the total area of all circular areas as the total sweep efficiency;

[0052] Determine the ratio of the area of the affected circular areas in the circular areas within the set radius range to the total area of all circular areas within the radius range as the sweep efficiency within the radius range.

[0053] Further, on the basis of determining the sweep coefficients in each radius interval, it may also include plotting a bar chart of the sweep degree, where the abscissa in the bar chart is the radius interval, and the ordinate is the sweep frequency and the sweep coefficient. The sweep frequency is used to characterize the total number of circular regions and the number of affected circular regions in each radius interval, and the sweep coefficient is used to characterize the sweep coefficient in each radius interval.

[0054] See Figure 6 As shown, it is a bar chart of the sweep degree of water drive pore throats. The abscissa in the figure is the pore throat radius interval; the left ordinate is the frequency, which is used to show the total number of circular regions in each radius interval and the number of affected circular regions in that interval; the right ordinate is the sweep efficiency (sweep coefficient), which is used to show the sweep coefficient in each radius interval.

[0055] The remaining oil production situation in each radius interval can be visually shown through the columns.

[0056] The method for determining the microscopic oil displacement sweep coefficient provided in the first embodiment of the present invention predefines the standard for the affected area as the crude oil at the center being displaced by the oil displacement medium; on this basis, microscopic images before and after oil displacement are obtained using microfluidic technology, and the pore throat distribution area and the displacement area of the oil displacement medium therein are obtained through segmentation processing, thereby microscopically realizing the characterization of the sweep characteristics at the level of the segmented circles in the pore throats; quantitatively characterizing the remaining oil production characteristics through the sweep coefficient is of great significance for the study of improving oil recovery in the high water cut stage; in addition, this method can achieve the fine calculation of the sweep coefficient at different pore throat radii.

[0057] A chip is made using microfluidic materials, and an oil displacement experiment is carried out on the chip using a microfluidic experimental device. Since the microfluidic materials are transparent, the displacement process and displacement effect can be directly observed through a microscope during the experiment.

[0058] In some embodiments, using a microfluidic experimental device, an oil displacement experiment is carried out on the chip with an oil displacement medium, including saturating the chip with simulated formation water using the microfluidic experimental device, and then saturating it with simulated crude oil until there is no water at the outlet end, and collecting the microscopic image before oil displacement at a set magnification; performing water flooding with simulated formation water until the oil-water distribution in the pore throats no longer changes, and collecting the microscopic image after oil displacement at the same magnification.

[0059] In some embodiments, it may also include performing enhanced oil recovery displacement with an enhanced oil recovery displacement medium on the basis of water flooding. Specifically, the remaining oil in the chip is continuously displaced with the enhanced oil recovery displacement medium until the volume of the injected enhanced oil recovery displacement medium reaches a set volume, and the microscopic image after displacing the remaining oil with the set volume of the enhanced oil recovery displacement medium is collected at a set magnification.

[0060] The enhanced oil recovery displacement medium can be any of the following media:

[0061] Polymers, binary composite systems of polymers and surfactants, and ternary composite systems of polymers, surfactants and alkaline agents.

[0062] In some embodiments, after the displacement medium for tertiary oil recovery displaces oil, it may further include segmenting the microscopic image of the set volume of the displacement medium for tertiary oil recovery after oil displacement to obtain the remaining oil distribution area after chemical flooding. By comparing the remaining oil distribution area after water flooding (obtained by segmenting the microscopic images before and after water flooding respectively) with the remaining oil distribution area after chemical flooding, the enlarged displacement area of the displacement medium for tertiary oil recovery is obtained.

[0063] See Figure 7 As shown, it is the pore-throat utilization distribution map of water flooding and polymer flooding (10PV) and polymer flooding (30PV) recorded on the basis of water flooding.

[0064] Example Two

[0065] Example Two of the present invention provides a specific implementation of a method for determining the microscopic oil displacement sweep efficiency.

[0066] 1. Experimental conditions

[0067] The experimental oil is a simulated oil prepared by mixing crude oil from a certain oilfield with kerosene, with a viscosity of 140 mPa·s (63 °C). The injected water during the water flooding stage is simulated formation water with a salinity of 7064 ppm. The concentration of the chemical flooding agent system is 1500 mg / L for the polymer concentration, 0.3% for the surfactant concentration, and 0.3% for the Na 2 CO 3 concentration. The viscosity of the polymer flooding system is 34 mPa·s, the viscosity of the polymer / surfactant binary composite flooding system is 34 mPa·s, and the viscosity of the polymer / surfactant / alkaline agent ternary composite flooding system is 31 mPa·s.

[0068] 2. Experimental apparatus

[0069] The microfluidic experimental apparatus includes an injection pump, a micro-flow pressure sensor, an intermediate container, a microscope, and a camera.

[0070] See Figure 8 As shown, it is a microfluidic experimental apparatus. The injection pump is a Harvard injection pump, specifically a Harvard Pump 11ELITE injection pump; the microscope is a ZEISS microscope, specifically a ZEISS V12 stereomicroscope; the camera is a SONY single-lens reflex camera.

[0071] 3. Experimental steps

[0072] (1) Connect the chip and each device of the microfluidic experimental apparatus using pipelines and check its sealing performance;

[0073] (2) After the chip is saturated with simulated formation water, saturate it with simulated crude oil until there is no water at the outlet end, judge that the chip is completely saturated, take a global picture of the microfluidic chip under the microscope, obtain the microscopic image before oil displacement collected at the set magnification, and record the original crude oil distribution.

[0074] (3) Start the Harvard constant-speed pump, then connect the injection liquid pipeline to the inlet end of the chip to simulate the water flooding process; use a microscopic pressure sensor to record the pressure change at the inlet end in real time, and observe the remaining oil distribution in the chip through a ZEISS microscope in real time.

[0075] (4) When the oil-water distribution in the chip no longer changes, end this displacement process, take a global picture at this stage, change the injection system, perform displacement again, and take a global picture at this stage; complete the polymer flooding, polymer / surfactant binary flooding, and polymer / surfactant / alkali ternary flooding experiments in sequence.

[0076] (5) After the experiment, clean the pipeline with anhydrous ethanol, and take the global pictures of each stage for observation and comparison.

[0077] 4. Calculation of sweep efficiency

[0078] Use professional image processing software to enhance the microscopic pictures taken in the experiment, then set specific parameter values for color block division, and then segment the image to complete the identification of remaining oil. According to the discrimination criteria of pore-throat sweep, extract the central axis skeleton ( Figure 5 ), obtain the distribution map of swept pores ( Figure 7 ), determine the pore area and the swept pore area, and then calculate the sweep efficiency.

[0079] Furthermore, it can be to use image algorithms such as distance transformation, central axis skeleton, and central axis dilation to determine the pore area and the swept pore area.

[0080] 5. Experimental results

[0081] The pore-throat sweep efficiency in the water flooding stage is generally lower than 20% ( Figure 6 ), while the pore-throat sweep efficiency of polymer flooding is significantly improved, from less than 20% to around 45% on average ( Figure 9 ); the addition of surfactant and alkali not only reduces the interfacial tension, but also reduces the flow difficulty of crude oil in the pore throat. On the basis of the mobility control of polymer flooding, it further improves the pore-throat sweep efficiency. The sweep degree of polymer / surfactant binary flooding is increased to around 68.81% on average ( Figure 10 ); the sweep degree of polymer / surfactant / alkali ternary composite flooding is increased to around 70.56% on average ( Figure 11 ). In summary, the pore-throat sweep efficiency: polymer flooding < polymer / surfactant binary flooding < polymer / surfactant / alkali ternary composite flooding.

[0082] It should be understood that the specific order or hierarchy of steps in the disclosed processes are examples of exemplary methods. Based on design preferences, it should be understood that the specific order or hierarchy of steps in a process may be rearranged without departing from the scope of the present disclosure. The appended method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy recited.

[0083] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are expressly recited in each claim. Rather, as reflected by the appended claims, the invention lies in less than all of the features of a single disclosed embodiment. Thus, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0084] The above description includes one or more examples of embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but one of ordinary skill in the art should recognize that the various embodiments may be further combined and arranged. Accordingly, the embodiments described herein are intended to embrace all such changes, modifications, and variations that fall within the scope of the appended claims. Further, with respect to the terms "comprising" used in the specification or claims, the manner in which this term is encompassed is similar to the term "including," as that term is interpreted when used as a transitional word in a claim. Additionally, any use of the term "or" in the claims or specification is to mean "non-exclusive or."

Claims

1. A method for determining the microscopic oil displacement sweep efficiency, characterized in that, it includes: Based on the pore-throat identification results of the thin-section pictures of rock samples, a chip is made using microfluidic materials; Using a microfluidic experimental device, an oil displacement experiment is carried out on the chip with an oil displacement medium to obtain microscopic images before and after oil displacement; The microscopic images before and after oil displacement are respectively subjected to segmentation processing to obtain the pore-throat distribution area and the displacement area of the oil displacement medium therein; According to the principle of the largest quantity and the largest area, the pore-throat distribution area is segmented into multiple circular areas; The circular area where displacement occurs at the center of the circle is determined as the swept circular area, and the sweep efficiency is determined according to the area of the swept circular area.

2. The method according to claim 1, characterized in that, the determining the sweep efficiency according to the area of the swept circular area includes performing at least one of the following: Taking the ratio of the areas of all swept circular areas to the total area of all circular areas as the total sweep efficiency; Taking the ratio of the area of the swept circular area in the circular areas within a set radius range to the total area of all circular areas within this radius range as the sweep efficiency within this radius range.

3. The method according to claim 2, characterized in that, after taking the ratio of the area of the swept circular area in the circular areas within a set radius range to the total area of all circular areas within this radius range as the sweep efficiency within this radius range, it further includes: Drawing a bar chart of the sweep degree, where the abscissa in the bar chart is the radius range, and the ordinate is the sweep frequency and the sweep efficiency. The sweep frequency is used to represent the total number of circular areas and the number of swept circular areas within each radius range, and the sweep efficiency is used to represent the sweep efficiency within each radius range.

4. The method according to claim 1, characterized in that, the respectively performing segmentation processing on the microscopic images before and after oil displacement to obtain the pore-throat distribution area and the displacement area of the oil displacement medium therein includes: Performing segmentation processing on the microscopic image before oil displacement to obtain the pore-throat distribution area and the crude oil distribution area therein; Performing segmentation processing on the microscopic image after oil displacement to obtain the remaining oil distribution area, and obtaining the displacement area of the oil displacement medium through the comparison between the remaining oil distribution area and the crude oil distribution area.

5. The method according to claim 4, characterized in that, the segmentation processing includes: First performing enhancement processing, setting specific parameter values for color block division, and then segmenting the image.

6. The method according to claim 1, characterized in that, the using a microfluidic experimental device to carry out an oil displacement experiment on the chip with an oil displacement medium includes: Using a microfluidic experimental device to saturate the chip with simulated crude oil until there is no water at the outlet end, and collecting the microscopic image before oil displacement at a set magnification; Performing water flooding by simulating formation water until the oil-water distribution in the pore throats no longer changes, and collecting the microscopic image after oil displacement at the set magnification.

7. The method according to claim 6, characterized in that, after collecting the microscopic image after oil displacement at the set magnification, it further includes: Use the displacement medium for enhanced oil recovery to continue displacing the remaining oil in the chip until the volume of the displacement medium for enhanced oil recovery injected is the set volume, and collect the microscopic image after displacing oil with the set volume of the displacement medium for enhanced oil recovery at the set magnification.

8. The method according to claim 7, wherein, the displacement medium for enhanced oil recovery is any one of the following media: polymer, binary composite system of polymer and surfactant, ternary composite system of polymer, surfactant and alkaline agent.

9. The method according to claim 7, wherein, obtaining the pore-throat distribution area and the displacement area of the displacement medium therein further includes: obtaining the remaining oil distribution area after water flooding in the pore-throat; correspondingly, after collecting the microscopic image after displacing oil with the set volume of the displacement medium for enhanced oil recovery at the set magnification, it further includes: Performing segmentation processing on the microscopic image after displacing oil with the set volume of the displacement medium for enhanced oil recovery to obtain the remaining oil distribution area after chemical flooding, and obtaining the enhanced displacement area of the displacement medium for enhanced oil recovery through the comparison between the remaining oil distribution area after water flooding and the remaining oil distribution area after chemical flooding.

10. The method according to any one of claims 1 to 9, wherein, the microfluidic experimental device includes an injection pump, a micro-flow pressure sensor, an intermediate container, a microscope and a camera.

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