Experimental method and system for microcosmically improving recovery ratio through nano mixed bubble water drive

Abstract

The embodiment of the invention provides an experimental method and system for microcosmically improving the recovery ratio through nanometer mixed bubble water drive. The experimental method comprises the steps that reservoir basic physical property parameters of a target reservoir block are determined; obtaining a target reservoir core and manufacturing a casting body sheet; identifying the pore structure of the casting body sheet so as to manufacture the micro-fluidic chip; saturating the experimental oil into the micro-fluidic chip by using a micro pump and a micro-fluidic pipeline; injecting the generated direct-current electric field modified nano mixed bubble water into a micro pump; and starting the camera and the image recognition system, opening the micro pump and setting the injection speed of the micro pump so as to start a direct-current electric field modified nano mixed bubble water displacement experiment. By means of the technical scheme, the direct-current electric field modified nano mixed bubble water, the microscopic direct-current electric field modified nano mixed bubble water drive system and the recovery efficiency improving effect and the remaining oil type conversion condition of the microscopic direct-current electric field modified nano mixed bubble water drive system are obtained, and a new technical path and a new solution are provided for quantitative evaluation of recovery efficiency improving of a nano bubble system.

Description

TECHNICAL FIELD

[0001] The application relates to an experimental method and system for microcosmic enhanced oil recovery of nano-mixed bubble water flooding. BACKGROUND

[0002] At present, the main oilfields in China have generally entered the middle and late stages of high water cut and high recovery degree. Long-term water flooding has further amplified the heterogeneity of the reservoir, and the interlayer / intra-layer contrast is strong, the permeability distribution is logarithmic normal, multi-stage pore throat and fractures form "advantageous flow", the connectivity between injection and production wells is strong, but the swept volume continues to decline; the remaining oil forms are gradually evolved from continuous phase to micro-heterogeneous remaining oil (clustered oil and porous flow oil), pore throat remaining oil (columnar oil), water dynamics remaining oil (blind-end oil), oil film (membrane oil) and oil droplet (droplet oil and island oil) types. A large amount of ineffective and inefficient circulating water and sewage treatment costs are high, therefore, the demand for systematic development of "controlling water and stabilizing oil, balanced production" is increasingly urgent. Conventional gas flooding, water alternating gas (WAG) and foam flooding can improve the mobility ratio, inhibit gravity displacement and gas channeling to some extent, but still face key bottlenecks in strong heterogeneous media. The low density and small viscosity of gas cause early breakthrough and fingering; foam is prone to instability and coarsening in high salinity and oil-containing environments, and shear / temperature / mineralization fluctuation causes foam strength attenuation; the interfacial active agent is easy to adsorb and lose, and the poor matching of the slug and the formation causes the problems of insufficient foam volume coefficient and effective action distance.

[0003] Micro / nano bubble water system has the dual characteristics of "simultaneously improving sweep efficiency and oil displacement efficiency" due to its controllable size, large specific surface area, surface charge, slow upward velocity, and long lifetime in water phase. Its mechanism in unconventional tight and strong heterogeneous reservoirs mainly includes: (1) Micro / nano scale units generate Jamin effect and selective temporary plugging at pore throat, preferentially inhibit invalid circulation in high permeability channels and fracture channels, force displacement front to divert to unproduced zones, and achieve "small disturbance to large, weak to strong" flow field redistribution; (2) After compounding with surfactants, it can significantly improve oil-water interface contact area and reduce interfacial tension, promote oil droplet deaggregation and migration, and induce weak water-wetness on rock surface, reducing the threshold of irreducible oil desorption; (3) Charged bubbles interact with the surface electrical properties of porous media, forming a stable micro-scale force field of repulsion / attraction, enhancing the film repulsion pressure and boundary slip effect, which helps to peel off the attached oil film and release the remaining oil in blind end pore channels; (4) By adjusting the bubble size distribution and volume fraction, the "deep profile control-near well water control" partitioning effect is realized, improving the sustainability and economy of deep sweep. Although micro / nano bubbles have longer lifetime than macro bubbles, they are still prone to coalesce, overflow and rupture in high temperature and high salinity reservoir environments, resulting in rapid decline of effective concentration. In the presence of oil phase and interfacial active agent, the bubble interface is more easily disturbed, showing coarsening and disappearance. Although the negative charge on the bubble surface can provide a certain electrostatic repulsion, it will be quickly shielded in high salinity or high ionic strength formation water, and the surface potential will decrease due to the compression of the double electric layer, weakening the interaction with rock and oil droplets. Therefore, an innovative technology is needed to optimize nano bubble water to improve oil recovery and determine its influence on the type of remaining oil.

[0004] Professor Hossameldeen Elnaggar of the University of Wyoming and others published an article entitled "Oil Recovery Enhancement by N Nanobubbles" in the journal Energy & Fuels in January 2025, which discloses that nanobubble water (mainly nitrogen nanobubbles) is used to displace cores represented by sandstone and carbonate rock. The experimental conditions are water-wet and oil-wet two wetting conditions, normal temperature and pressure to high temperature (about 120 DEG C) and high pressure range. The experimental results show that: compared with distilled water, nanobubble water shows higher recovery rate and more uniform front interface under different lithology and wetting conditions. Microscopic mechanism analysis: the synergistic effect is mainly derived from the regulation of nanobubbles on the interface / wettability. This achievement provides experimental basis and mechanism explanation for economic enhanced oil recovery in high water cut and strong heterogeneous reservoirs. This study only involves nitrogen nanobubble water, and does not consider the influence of multiple gas composite bubble systems on recovery rate. The mechanism study only considers the influence of nanobubbles on the interface / wettability, and does not consider the influence of surface charge and bubble stability on the recovery rate. The study considers the "invisible" enhanced oil recovery experiment at the core scale, and cannot identify the type of remaining oil and its type conversion law.

[0005] An experimental method for improving oil recovery by using carbon dioxide microbubbles is disclosed in CN114113550B. The method establishes an experimental system that can generate CO microbubbles (about 10-100 μm in diameter) in situ in a reaction kettle and carry out micro-displacement in porous media: by periodically switching the gas and liquid channels through a gas-liquid three-way valve / microfluidic structure to form stable microbubbles, the temperature and pressure are controlled, and then the microbubbles are injected into the core model together with the oil displacement solution. The migration of microbubbles in pore throats, the selective temporary plugging of the Jiamin effect, and the change in oil phase volume fraction are observed in real time. Compared with ordinary bubbles, the microbubble system exhibits better injection performance and micro-enhanced oil recovery effect in low-permeability / ultra-low-permeability media, with an oil recovery enhancement of about 16.1%. It also has CO storage potential, providing a reproducible experimental path and quantitative evaluation index for the oil-increasing mechanism and formulation optimization of nanobubble / water flooding in strong heterogeneous conditions. Although this scheme improves oil and gas recovery in low-permeability / ultra-low-permeability media, the bubbles are single carbon dioxide bubbles, and the synergistic effect is mainly derived from the physical properties of carbon dioxide gas and the physical properties of nanobubbles, which are weakly related. The size, distribution, charge density, and matching with reservoir rocks are not optimized. At the same time, the core displacement experiment is invisible, and it is difficult to effectively identify the conversion law of different types of remaining oil, and further optimization is not possible. SUMMARY

[0006] The purpose of the embodiments of the present application is to provide an experimental method and system for micro-enhanced oil recovery by nanobubble water flooding.

[0007] To achieve the above object, the first aspect of the present application provides an experimental method for microcosmic enhanced oil recovery by nanometer mixed bubble water flooding, which comprises a generating device for generating direct current field modified nanometer mixed bubble water, a micro pump, a microfluidic chip, a camera and an image recognition system. The generating device comprises an electrolytic cell, a direct current power supply and a proton exchange membrane, the proton exchange membrane comprises a positive electrode, a negative electrode and a cation exchange membrane between the positive electrode and the negative electrode, the micro pump is connected with the microfluidic chip through a microfluidic pipeline, the camera is used to take images of the microfluidic chip, and the image recognition system is used to recognize the images. The experimental method comprises the following steps:

[0008] determining basic reservoir physical property parameters of a target reservoir block;

[0009] obtaining a target reservoir core and making a cast thin section;

[0010] identifying the pore structure of the cast thin section by using an image recognition technology to make a microfluidic chip;

[0011] saturating experimental oil into the microfluidic chip by using a micro pump and a microfluidic pipeline;

[0012] generating direct current field modified nanometer mixed bubble water by using the generating device;

[0013] injecting the generated direct current field modified nanometer mixed bubble water into the micro pump;

[0014] starting the camera and the image recognition system, turning on the micro pump and setting the injection speed of the micro pump to start the direct current field modified nanometer mixed bubble water flooding experiment.

[0015] In the embodiment of the present application, after starting the direct current field modified nanometer mixed bubble water flooding experiment, the image recognition system performs image recognition according to the images of the microfluidic chip obtained from the camera to obtain a remaining oil distribution map and the amount and conversion of different types of remaining oil;

[0016] When the image recognition system identifies that the remaining oil saturation degree does not change within a time period according to the image recognition, the flooding experiment ends.

[0017] In the embodiment of the present application, the experimental method further comprises:

[0018] analyzing the images obtained by the image recognition system and the obtained data.

[0019] In the embodiment of the present application, the step of generating direct current field modified nanometer mixed bubble water by using the generating device comprises:

[0020] Nitrogen, carbon dioxide, or deoxygenated air nanobubbles obtained through mechanical stirring are loaded into the electrolytic cell, and a DC power supply is used to electrolyze the nanobubbles to generate DC electric field modified nano-mixed bubble water at the negative electrode.

[0021] In this embodiment of the application, the step of saturating the experimental oil into the microfluidic chip using a micropump and microfluidic pipeline includes:

[0022] Experimental oil is injected into the microfluidic chip via the micro-pump and the microfluidic pipeline.

[0023] The image recognition system acquires images of the microfluidic chip captured by the camera;

[0024] When the image recognition system identifies that the color of the acquired image is uniform and the color of the image does not change after the micro-pump continues to input experimental oil at a set flow rate for a period of time, the injection of experimental oil into the microfluidic chip is stopped.

[0025] In this embodiment of the application, the basic physical property parameters include at least one of the following:

[0026] Reservoir temperature, reservoir porosity, reservoir permeability, and reservoir structure.

[0027] In this embodiment, the microfluidic chip includes a PDMS chip or a glass chip.

[0028] The second aspect of this application provides an experimental system for microscopically enhancing oil recovery through nano-mixed bubble water flooding, comprising:

[0029] A generating device for generating DC electric field modified nano-mixed bubble water, the generating device including an electrolytic cell, a DC power supply and a proton exchange membrane, the proton exchange membrane including a positive electrode, a negative electrode and a cation exchange membrane located between the positive electrode and the negative electrode, the DC power supply including a DC power supply, the positive electrode and the negative electrode of the DC power supply being electrically connected to the positive electrode and the negative electrode respectively;

[0030] The microfluidic chip is configured to receive experimental oil during displacement experiments;

[0031] A micropump is connected to the microfluidic chip via a microfluidic pipeline. The micropump is used to inject the DC electric field modified nano-mixed bubble water into the microfluidic chip, which is saturated with experimental oil.

[0032] A camera, disposed on top of the microfluidic chip, is configured to capture images of the microfluidic chip;

[0033] The processor is configured to acquire images transmitted by the camera and invoke an image recognition system to recognize the images.

[0034] In this embodiment of the application, after the DC electric field modified nano-mixed bubble water displacement experiment is started, the image recognition system performs image recognition based on the image of the microfluidic chip obtained from the camera to obtain the remaining oil distribution map and the amount of different types of remaining oil and their conversion status.

[0035] When the image recognition system identifies that the remaining oil saturation has not changed within a certain time period based on the image, it indicates that the displacement experiment has ended.

[0036] In this embodiment of the application, the experimental system further includes:

[0037] A light-emitting plate, positioned at the bottom of the microfluidic chip, is used to provide uniform background light.

[0038] Through the above technical solutions, we obtained DC electric field modified nano-mixed bubble water, micro DC electric field modified nano-mixed bubble water drive system, and its enhanced oil recovery effect and residual oil type conversion, providing a new technical path and solution for quantitative evaluation of enhanced oil recovery of nano-bubble system.

[0039] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0040] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 and Figure 2 A block diagram of a nano-hybrid bubble water drive test system according to an embodiment of this application is shown schematically.

[0042] Figure 3 This is a use according to the embodiments of this application. Figure 1 and Figure 2 The flowchart shows the experimental method for using a DC electric field modified nano-mixed bubble water drive to achieve microscopic enhanced oil recovery and residual oil type conversion.

[0043] Figure 4 The results of improved recovery rate shown in the embodiments of this application are illustrated;

[0044] Figure 5 The results of residual oil type conversion in an embodiment of this application are shown.

[0045] Explanation of reference numerals in the attached figures

[0046] 1 Electrolyzer 2 DC-modified positive electrode mixed with nano-bubble water

[0047] 3 Nitrogen nanobubbles 4 Oxygen nanobubbles

[0048] 5 Positive electrode 6 Cation exchange membrane

[0049] 7. Cation exchange membrane interlayer 8. Negative electrode

[0050] 9. Hydrogen nanobubbles 10. DC-modified negative electrode mixed with nanobubble water

[0051] 11 Electrode wire 12 DC power supply

[0052] 13 Oil phase intermediate container 14 Oil syringe

[0053] 15 DC-modified positive electrode mixed with nanobubbles in an aqueous phase intermediate container

[0054] 16 DC-modified positive electrode mixed with nanobubble aqueous phase injector

[0055] 17 Computer 18 Image Recognition System

[0056] 19 Micro-infusion pump 20 Camera

[0057] 21 PDMS chip or glass chip 22 Light-emitting board Detailed Implementation

[0058] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0059] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0060] The following terms may be used in this application:

[0061] Nanobubble water: A large number of nano-sized bubbles exist stably in the aqueous phase.

[0062] DC electric field modification: Through the electrolysis effect of DC electric field, hydrogen ions in water are converted into hydrogen gas, forming a liquid rich in hydroxide anions, which accumulate in large quantities on the surface of nanobubbles.

[0063] Micron-sized bubble water: A large number of micron-sized bubbles exist stably in the aqueous phase.

[0064] Oil recovery rate: The percentage of total crude oil extracted from an oil field relative to its original geological reserves.

[0065] Microscopic residual oil types: The types of crude oil that has not been extracted and is found in microscopic pores and throats, including: microscopic heterogeneous residual oil (cluster oil and porous flow oil), pore throat residual oil (columnar oil), hydrodynamically stagnant oil (blind end oil), oil film (film oil) and oil droplets (droplet oil and island oil).

[0066] The Jamin effect: The capillary pressure difference generated by bubbles in the pore throat increases the flow resistance of the fluid, hinders the flow of hypertonic channels, and improves the fluid sweep area.

[0067] Sweep efficiency: refers to the percentage of the total reservoir volume swept by the injected displaced phase.

[0068] Washing efficiency: refers to the percentage of crude oil volume displaced within the reservoir area affected by injected water, relative to the original oil storage volume in that area.

[0069] Existing technologies involve various approaches such as surface preparation or wellbore injection of micro / nano bubbles, synergistic injection and production in single and multi-well systems, and composite formulations with surfactants / polymers / foams. However, they generally do not study the effects of microscale enhanced oil recovery and residual oil type conversion from the perspective of electrochemical modification coupled with electric bilayer regulation.

[0070] Compared to existing technologies, this application proposes a solution for microscopic enhanced oil recovery and residual oil type conversion using DC electric field-modified nano-mixed bubble water to address the limitations of conventional nano-bubble water in enhancing oil recovery and residual oil type conversion. This solution utilizes DC electrolysis of nano-bubble water to prepare multi-component gas nano-mixed bubbles in situ, and the large number of hydroxide ions generated during electrolysis are adsorbed at the bubble interface, significantly increasing the absolute value of the bubble surface zeta potential, thereby enhancing bubble stability and displacement effectiveness. Simultaneously, a visual integrated experimental system is constructed, consisting of a PDMS microfluidic chip, micropump, optical plate, camera, computer, microfluidic pipeline, and residual oil type image recognition module, for conducting microscopic displacement experiments using DC electric field-modified nano-mixed bubble water. Compared to existing invisible nano-bubble water experiments, this system can identify different residual oil types and their conversion processes in real time, achieving integrated "preparation-displacement-identification-analysis," providing a new technical path and solution for quantitative evaluation of enhanced oil recovery using nano-bubble systems.

[0071] Figure 1 and Figure 2A block diagram of a nano-hybrid bubble water-drive experimental system according to an embodiment of this application is shown schematically. (Reference) Figure 1 and Figure 2 In this embodiment of the application, the nano-mixed bubble water drive test system (hereinafter referred to as the test system) may include:

[0072] A device for generating nano-mixed bubble water modified by a DC electric field is disclosed. The device may include an electrolyzer 1 and a DC power supply 12. A proton exchange membrane is disposed in the electrolyzer 1. The proton exchange membrane may include a positive electrode 5 and a negative electrode 8, and a cation exchange membrane 6 located between the positive electrode 5 and the negative electrode 8. The DC power supply 12 may include a DC generator, whose positive and negative terminals may be connected (e.g., via wires or other electrodes) to the positive electrode 5 and the negative electrode 8, respectively. When it is necessary to prepare DC electric field modified nano-mixed bubble water, the DC power supply 12 can be turned on, and nitrogen (or carbon dioxide or deoxygenated air) nano-bubble water obtained by (mechanical) stirring can be loaded into the electrolysis cell 1. After the DC power supply 12 electrolyzes the nano-bubble water for a period of time (e.g., electrolysis time of 1 to 3 hours), the DC electric field modified nano-mixed bubble water in the negative electrode after electrolysis can be loaded into the micro-pump 19. The end of the micro-pump 19 is connected to a microfluidic pipeline, which is connected to the injection end and the outlet end of the microfluidic chip 21 (e.g., PDMS chip or glass chip). Specifically, the oil phase intermediate container 13 is used to store the experimental oil, and the micro-pump 19 may include an oil injector 14, which is connected to the microfluidic chip 21 through the microfluidic pipeline. The injection speed of the micro-pump 19 can be set, and the micro-pump 19 drives the oil injector 14 to move to inject the loaded experimental oil into the microfluidic chip 21. The intermediate container 15 for the DC-modified cathode mixed nanobubble aqueous phase is used to store the DC-modified cathode mixed nanobubble water. The micropump 19 may also include a DC-modified cathode mixed nanobubble aqueous phase injector 16, which is connected to the microfluidic chip 21 via a microfluidic pipeline. The injection rate of the micropump 19 can be set, and the micropump 19 drives the injector 16 to inject the DC-modified cathode mixed nanobubble water into the microfluidic chip 21. A light-emitting plate 22 is placed at the bottom of the PDMS chip 21 to ensure consistent light intensity during the experiment. The light-emitting plate 22 may include a light source (e.g., an LED strip or light array) that provides uniform background light. Micropump 19 is activated for micro-displacement. Camera 20 is placed above PDMS chip 21. Camera 20 can capture images of PDMS chip 21 at regular intervals (e.g., 10 seconds). The images can be transmitted to processor (e.g., computer) 17. Processor 17 can call residual oil type image recognition system 18 to perform real-time image recognition, obtain residual oil distribution map and quantitative data, and realize the integration of "preparation-displacement-recognition-analysis". In the embodiments of this application, the number of PDMS chips can include one or more, and can be dual-chip parallel or multi-chip parallel. In one example, the placement direction of PDMS chips is not limited to horizontal placement relative to the light-reflecting plate 22, but can also be vertical placement or tilted placement (with an angle of tilt relative to the horizontal plane). PDMS chip, also known as PDMS microfluidic chip, PDMS stands for polydimethylsiloxane, which is a common organic polymer used in the prototype manufacturing of microfluidic chips. It is elastic, transparent, breathable, and chemically inert.Suitable for chip manufacturing related to cell culture, drug screening, and cell capture, the material itself is hydrophobic and can be surface modified by chemical or physical means.

[0073] Another embodiment of this application provides a usage reference. Figure 1 and Figure 2 This embodiment describes an experimental method for achieving microscopic enhanced oil recovery and residual oil type conversion through a DC electric field-modified nano-mixed bubble water flooding test system. (Reference) Figure 3 In the embodiments of this application, the experimental method may include the following steps.

[0074] In step S110, the basic reservoir physical properties of the target reservoir block are determined. In one example, the basic physical properties may include reservoir temperature, reservoir porosity, reservoir permeability, reservoir structure, etc.

[0075] In step S120, the target reservoir core is obtained and a cast thin section is fabricated. Specifically, the target reservoir core can be selected based on the basic physical properties of the reservoir and geological exploration data, and a cast thin section can be fabricated based on this core.

[0076] In step S130, image recognition technology is used to identify the pore structure of the cast thin film, thereby fabricating a microfluidic chip. Taking a PDMS chip as an example, specifically, after identifying the pore structure, a PDMS chip design of a certain size can be designed using software such as AutoCAD, and the PDMS chip can be fabricated according to the design. The fabrication process of PDMS chips is well known in the art and will not be described in detail here.

[0077] In step S140, the experimental oil is saturated into the microfluidic chip using a micropump and microfluidic tubing. Specifically, while injecting the experimental oil into the microfluidic chip using the micropump and microfluidic tubing, a camera can capture images of the microfluidic chip in real time and transmit the captured images to a processor. The processor calls an image recognition system to recognize the images. When the image recognition system recognizes that the color of the image is uniform and that the color of the image does not change after continuing to inject the experimental oil at a set flow rate (e.g., 5 μl / min) for a period of time (e.g., 1 hour), it can be considered that saturation is complete, and the injection of experimental oil into the microfluidic chip can be stopped.

[0078] In step S150, a DC electric field modified nano-mixed bubble water is generated using a generating device.

[0079] In step S160, the generated DC electric field modified nano-mixed bubble water is injected into a micro-pump, which is connected to a microfluidic chip through a microfluidic pipeline.

[0080] In step S170, the illumination plate at the bottom of the microfluidic chip, the camera at the top of the microfluidic chip, and the residual oil type image recognition system are turned on. The micropump is then turned on and its injection rate is set to begin the DC electric field modified nano-mixed bubble water displacement experiment. Specifically, during the micro-displacement, the image recognition system simultaneously performs image recognition to obtain a residual oil distribution map and the amount and conversion status of different types of residual oil. The experiment ends when the image recognition system identifies no significant change in the residual oil saturation over a time period (e.g., 1 hour).

[0081] In step S180, after the experiment, the images and data acquired by the image recognition system can be analyzed. Specifically, the image recognition system can extract relevant data from the images after recognition, such as the distribution of remaining oil, the amount of different types of remaining oil, and their conversion status.

[0082] Example

[0083] The experimental method for improving oil recovery and converting residual oil type through DC electric field modification of nano-mixed bubble water flooding includes the following steps.

[0084] (1) Select target reservoir cores based on reservoir physical parameters and geological exploration data, and prepare cast thin sections;

[0085] (2) Using image recognition technology and AutoCAD 2026 software, draw the microscopic pore structure diagram of the cast thin sheet and fabricate a PDMS chip;

[0086] (3) Saturated reservoir crude oil was injected into the PDMS chip using a micro-pump at a flow rate of 5 μl / min, and image recognition was used until the color of the crude oil in the chip did not change significantly within 1 hour.

[0087] (4) Connect the DC motor to the nanobubble water obtained with mechanical stirring, adjust the voltage to 8V, and electrolyze for 1.5 hours. Then, load the negative electrode liquid into a micro-pump to prepare for the microscopic displacement experiment. Figure 2 As shown;

[0088] (5) A DC electric field modified nano-mixed bubble water drive test system is formed by interconnecting a micro-pump, PDMS microfluidic chip, optical plate, camera, computer, microfluidic pipeline, and residual oil type image recognition module. Figure 3 As shown;

[0089] (6) Set the injection rate to 5 μl / min, set the light plate to constant brightness, turn on the computer and the residual oil type image recognition module, and start the micro displacement experiment.

[0090] (7) During the micro-displacement process, image recognition is performed simultaneously to obtain the remaining oil distribution map and the amount and conversion status of different types of remaining oil.

[0091] (8) The experiment ends when there is no significant change in the remaining oil saturation within 1 hour.

[0092] (9) Detailed analysis of the residual oil distribution transformation map and data obtained by the residual oil type image recognition module.

[0093] Results of improved recovery rate Figure 4 As shown, the image and data results of the remaining oil type conversion are as follows: Figure 5 As shown. Indoor physical simulation experiments of the DC electric field modified nano-mixed bubble water flooding method of this embodiment for microscopic enhanced oil recovery and residual oil type conversion revealed that the enhanced oil recovery effect of the DC electric field modified nano-mixed bubble water proposed in this embodiment is 4 percentage points higher than that of conventional nano-bubble water. Furthermore, the visualized microscopic displacement experiment, combined with the residual oil type image recognition module, can visualize and quantify the distribution and conversion patterns of different types of residual oil.

[0094] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0095] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An experimental method for microscopically enhancing oil recovery through nano-mixed bubble water flooding, characterized in that, The nano-mixed bubble water-driven experimental system includes a generating device for generating DC electric field-modified nano-mixed bubble water, a micropump, a microfluidic chip, a camera, and an image recognition system. The generating device includes an electrolyzer, a DC power supply, and a proton exchange membrane. The proton exchange membrane includes a positive electrode, a negative electrode, and a cation exchange membrane located between the positive and negative electrodes. The micropump is connected to the microfluidic chip via a microfluidic pipeline. The camera is used to capture images of the microfluidic chip, and the image recognition system is used to recognize the images. The experimental method includes: Determine the basic reservoir physical properties of the target reservoir block; Obtain core samples from the target reservoir and fabricate thin sections; Image recognition technology is used to identify the pore structure of cast thin films, thereby fabricating microfluidic chips; The experimental oil was saturated into the microfluidic chip using a micropump and microfluidic pipeline. The aforementioned generating device is used to generate DC electric field modified nano-mixed bubble water; The generated DC electric field modified nano-mixed bubble water is injected into the micro-pump; Start the camera and the image recognition system, turn on the micro-pump and set the injection speed of the micro-pump to begin the DC electric field modified nano-mixed bubble water displacement experiment.

2. The experimental method according to claim 1, characterized in that, After the DC electric field modified nano-mixed bubble water displacement experiment is started, the image recognition system performs image recognition based on the image of the microfluidic chip obtained from the camera to obtain the remaining oil distribution map and the amount of different types of remaining oil and their conversion status. The displacement experiment ends when the image recognition system determines that the remaining oil saturation has not changed over a period of time.

3. The experimental method according to claim 1, characterized in that, Also includes: The images and data acquired by the image recognition system are analyzed.

4. The experimental method according to claim 1, characterized in that, The process of generating DC electric field modified nano-mixed bubble water using the generating device includes: Nitrogen, carbon dioxide, or deoxygenated air nanobubbles obtained through mechanical stirring are loaded into the electrolytic cell, and a DC power supply is used to electrolyze the nanobubbles to generate DC electric field modified nano-mixed bubble water at the negative electrode.

5. The experimental method according to claim 1, characterized in that, The process of saturating the experimental oil into the microfluidic chip using a micropump and microfluidic pipeline includes: Experimental oil is injected into the microfluidic chip via the micro-pump and the microfluidic pipeline. The image recognition system acquires images of the microfluidic chip captured by the camera; When the image recognition system identifies that the color of the acquired image is uniform and the color of the image does not change after the micro-pump continues to input experimental oil at a set flow rate for a period of time, the injection of experimental oil into the microfluidic chip is stopped.

6. The experimental method according to claim 1, characterized in that, The basic physical property parameters include at least one of the following: Reservoir temperature, reservoir porosity, reservoir permeability, and reservoir structure.

7. The experimental method according to claim 1, characterized in that, The microfluidic chip includes a PDMS chip or a glass chip.

8. An experimental system for microscopically enhancing oil recovery through nano-mixed bubble water flooding, characterized in that, include: A generating device for generating DC electric field modified nano-mixed bubble water, the generating device including an electrolytic cell, a DC power supply and a proton exchange membrane, the proton exchange membrane including a positive electrode, a negative electrode and a cation exchange membrane located between the positive electrode and the negative electrode, the DC power supply including a DC power supply, the positive electrode and the negative electrode of the DC power supply being electrically connected to the positive electrode and the negative electrode respectively; The microfluidic chip is configured to receive experimental oil during displacement experiments; A micropump is connected to the microfluidic chip via a microfluidic pipeline. The micropump is used to inject the DC electric field modified nano-mixed bubble water into the microfluidic chip, which is saturated with experimental oil. A camera, disposed on top of the microfluidic chip, is configured to capture images of the microfluidic chip; The processor is configured to acquire images transmitted by the camera and invoke an image recognition system to recognize the images.

9. The experimental system according to claim 8, characterized in that, After the DC electric field modified nano-mixed bubble water displacement experiment is started, the image recognition system performs image recognition based on the image of the microfluidic chip obtained from the camera to obtain the remaining oil distribution map and the amount of different types of remaining oil and their conversion status. When the image recognition system identifies that the remaining oil saturation has not changed within a certain time period based on the image, it indicates that the displacement experiment has ended.

10. The experimental system according to claim 8, characterized in that, Also includes: A light-emitting plate, positioned at the bottom of the microfluidic chip, is used to provide uniform background light.

Images