CCUS experimental device and method for carbon dioxide flooding and storage

Abstract

The invention discloses a CCUS experimental device and method for carbon dioxide flooding and storage, and relates to the technical field of petroleum engineering. The device comprises a three-dimensional oil reservoir physical model, a fluid injection system, a fluid collecting and metering system, a resistivity monitoring system and a fluid migration observation system. The three-dimensional oil reservoir physical model is used for constructing a simulated stratum, and a development well pattern system is installed on the simulated stratum; the fluid injection system is connected with the injection well; the fluid collecting and metering system is connected with the production well; the resistivity monitoring system is provided with a plurality of monitoring points on the simulated stratum; the fluid migration observation system is used for observing a migration path of supercritical carbon dioxide in the three-dimensional oil reservoir physical model; and the distributed optical fiber monitoring system is arranged in the simulated stratum. According to the device and the method, oil reservoir water injection exploitation and CO2 injection oil displacement and CO2 storage stability simulation experiments in the later development period can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum engineering, and in particular to a CCUS experimental device and method for carbon dioxide oil recovery and storage. Background Art

[0002] In the oil industry, carbon dioxide utilization and storage (CCUS) refers to the injection of CO2 into oil and gas reservoirs to displace oil or natural gas, increasing oil and gas recovery. Simultaneously, a significant portion of the CO2 is retained underground and permanently sealed in formation pores, achieving carbon sequestration. Complex phase changes and fluid mass transfer processes occur during and after CO2 injection into oil and gas reservoirs. Accurately characterizing the fluid migration behavior and seepage mechanisms after CO2 injection is crucial for accurately evaluating CO2 displacement efficiency, understanding the characteristics of the CO2 plume in the reservoir, and analyzing CO2 storage patterns and long-term storage processes.

[0003] CCUS technology is a win-win initiative for achieving enhanced oil and gas recovery and carbon emission reduction. Currently, there are two main approaches to studying the CCUS mechanisms in oil and gas reservoirs. The first is numerical simulation, which can reconstruct the reservoir structure and fluid distribution, and simulate the fluid migration and pressure distribution during CO2 injection. However, numerical simulations do not adequately account for complex phase changes, interfacial behavior, and mass transfer and migration, and cannot accurately describe the CCUS process in oil and gas reservoirs. The second is physical simulation technology, which accurately describes the CCUS process and mechanism by replicating formation conditions and fluid injection processes.

[0004] Visualizing the CO2 displacement process, oil and gas migration patterns, and post-storage fluid migration is crucial for understanding the CCUS mechanisms of oil and gas reservoirs. However, existing CCUS physical simulation technology experimental devices are limited in functionality, typically demonstrating the CO2 enhanced oil recovery effect through simple displacement experiments. They lack real-time monitoring and quantitative analysis of multiple physical fields (such as saturation changes, CO2 migration pathways, formation strain, and CO2 storage volume calculations), making it difficult to intuitively study complex subsurface fluid interactions, migration, and storage mechanisms. Therefore, developing an innovative CCUS experimental device system is of great practical significance. Summary of the Invention

[0005] The purpose of the present invention is to provide a CCUS experimental device and method for carbon dioxide recovery and storage, aiming to solve or improve at least one of the above-mentioned technical problems.

[0006] To achieve the above object, the present invention provides the following solutions: A CCUS experimental device for CO2 flooding and storage, comprising: A three-dimensional reservoir physical model, wherein the three-dimensional reservoir physical model is used to construct a simulated formation, and a development well pattern system is installed on the simulated formation; the development well pattern system includes an injection well (16) and a production well (23); A fluid injection system connected to the injection well (16) for injecting a salt solution simulating formation water of a specified concentration of a target oil reservoir and a 1,8-naphthaleneimide-based fluorescent dye fully dissolved in supercritical carbon dioxide into the simulated formation; A fluid collection and metering system, connected to the production well (23), for collecting and calculating the volume of produced oil; a resistivity monitoring system, wherein the resistivity monitoring system is provided with a plurality of monitoring points on the simulated formation for monitoring the distribution of fluid saturation in the simulated formation; a fluid migration observation system, the fluid migration observation system being used to observe the migration path of supercritical carbon dioxide in the three-dimensional reservoir physical model; A distributed optical fiber monitoring system is provided in the simulated stratum, and is used to transmit the emitted optical signals to each stratum, and calculate the strain using the received optical signals to draw a strain field map of the sealing stratum.

[0007] Optionally, the three-dimensional reservoir physical model specifically includes: a pressure patrol meter, a three-dimensional reservoir model, a constant temperature box and a temperature gauge; the three-dimensional reservoir model is arranged inside the constant temperature box to construct a simulated formation; the constant temperature box is used to maintain the formation temperature; the temperature gauge is arranged on the constant temperature box to adjust the temperature of the constant temperature box; the pressure patrol meter is arranged at the pressure test point of the simulated formation to monitor the formation pressure.

[0008] Optionally, the fluid injection system specifically includes: a formation water bottle, a simulated oil bottle, a formation water intermediate container, a simulated oil intermediate container, a double-rod constant pressure pump, a 1,8-naphthaleneimide-based fluorescent dye bottle, a first valve, a supercritical carbon dioxide bottle, a supercritical carbon dioxide intermediate container, a six-way valve, a first gas flow meter, a bracket and a third pressure gauge; The output end of the formation water bottle is connected to the formation water intermediate container and the input end of the double-rod constant pressure pump respectively; the output end of the simulated oil bottle is connected to the simulated oil intermediate container and the input end of the double-rod constant pressure pump respectively; The 1,8-naphthaleneimide fluorescent dye bottle, the supercritical carbon dioxide bottle arranged on the bracket and the supercritical carbon dioxide intermediate container are connected in sequence, and the first valve is also provided on the connecting pipeline between the 1,8-naphthaleneimide fluorescent dye bottle and the supercritical carbon dioxide bottle; the output end of the double-rod constant pressure pump is also connected to the input end of the supercritical carbon dioxide intermediate container; the output end of the supercritical carbon dioxide intermediate container is connected to the input end of the first gas flowmeter; the output ends of the formation water intermediate container, the simulated oil intermediate container and the first gas flowmeter are all connected to the six-way valve; the six-way valve is also connected to the injection well, and the third pressure gauge is also provided on the connecting pipeline between the six-way valve and the injection well.

[0009] Optionally, the fluid collection and metering system specifically includes: a second valve, a back pressure pump, a first pressure gauge, a fluid collection device, a third valve, a second gas flow meter, a second pressure gauge, a vacuum pump, a gas collection device and a back pressure valve; The production well is connected to the second valve through a first branch, and the production well is connected to the third valve through a second branch; the second valve is also connected to the first pressure gauge; the first pressure gauge is connected to the back pressure pump through a first connecting pipeline, and the back pressure valve is also installed on the first connecting pipeline; the first pressure gauge is connected to the fluid collection device through a second connecting pipeline; the fluid collection device is also connected to the second gas flow meter and the gas collection device in sequence; the third valve is also connected to the vacuum pump, and the second pressure gauge is also provided on the connecting pipeline between the third valve and the vacuum pump.

[0010] Optionally, the resistivity monitoring system specifically comprises: a saturation data processing system, a resistivity sensor and a plurality of resistivity probes; Each of the resistivity probes is arranged in a set arrangement in the simulated formation, and each of the resistivity probes is connected to the resistivity sensor; the resistivity sensor is also connected to the saturation data processing system.

[0011] Optionally, the fluid migration observation system specifically comprises: a high-resolution camera, a visual observation window, an optically transparent window, an image processing and analysis system, and a slidable bracket; The optically transparent window is arranged on one side of the three-dimensional reservoir physical model, and the high-resolution camera is installed on the slidable bracket and is arranged on the other side of the three-dimensional reservoir physical model relative to the optically transparent window; the high-resolution camera is also connected to the image processing and analysis system; the visual observation window is opened on at least one side of the three-dimensional reservoir physical model.

[0012] Optionally, the distributed optical fiber monitoring system specifically comprises: a first optical fiber coupler, an optical signal transmitter, a distributed optical fiber, an optical signal receiver, an optical signal processing and analysis system, and a second optical fiber coupler; The optical signal transmitter, the first optical fiber coupler and one end of the distributed optical fiber are connected in sequence, and the other end of the distributed optical fiber is also connected in sequence to the second optical fiber coupler, the optical signal receiver and the optical signal processing and analysis system.

[0013] The present invention also provides a CCUS experimental method for carbon dioxide flooding and storage, which is applied to the above-mentioned device and comprises: Based on the CCUS experimental device, a simulated formation is constructed according to the physical parameters and reservoir characteristic parameters of the target oil reservoir, and the simulated formation is used to carry out reservoir depletion recovery, water injection and CO2 injection to monitor the stability of CO2 storage. The reservoir depletion recovery process includes: opening a production well in the three-dimensional reservoir physical model until no more oil is produced in the fluid collection and metering system, and then calculating the produced oil volume.

[0014] Optionally, both the water flooding and CO2 flooding processes include monitoring of fluid saturation and formation pressure; The water injection oil displacement process specifically includes: 0.1 Inject formation water through the injection well, open the production well, and calculate the volume of produced oil when no more oil is produced in the fluid collection and metering system; During the water injection process, resistivity probe data is collected every ten minutes. The fluid saturation is measured based on the resistivity and a fluid saturation map is drawn to monitor the distribution of fluid saturation in the formation. The pressure patrol meter is also used to monitor the changes in formation pressure during the water injection process in real time. The CO2 injection flooding process specifically includes: 0.1 Inject supercritical carbon dioxide through the injection well, open the production well, and calculate the volume of produced oil when no more oil is produced in the fluid collection and metering system; During the supercritical carbon dioxide injection process, the fluid migration observation system is used to observe and photograph the supercritical carbon dioxide injection front and the migration path of carbon dioxide in complex pores. Resistivity probe data is collected every ten minutes, and the fluid saturation is measured based on the resistivity and a fluid saturation map is drawn to monitor the fluid saturation distribution in the formation. The pressure patrol meter is used to monitor the changes in formation pressure during the water injection process in real time.

[0015] Optionally, the process of monitoring the CO2 storage stability includes: The distributed optical fiber monitoring system is used to calculate the formation strain and draw a strain field map of the storage layer. The calculation formula of the formation strain is: , in, is the average wavelength, is the wavelength shift, is the average optical frequency, is the optical frequency shift, is the strain sensitivity coefficient, is the optical fiber strain, is the temperature sensitivity coefficient, is temperature change; Calculate the amount of CO2 stored: , in, is the CO2 injection amount, ; is the CO2 output, ; is the CO2 storage capacity, ; A high-resolution camera is used to continuously capture the fluorescence of supercritical CO2, recording time-series images. The image processing and analysis system converts the fluorescence intensity into a pseudo-color image of CO2 concentration, identifying the retention characteristics of CO2 in low-permeability areas and the rapid migration of CO2 in high-permeability channels, enabling visual monitoring of CO2 diffusion and migration during oil recovery. The formation pressure is monitored by a pressure patrol instrument. Real-time monitoring of the formation pressure prevents formation rupture or carbon dioxide leakage caused by pressure accumulation, and prevents the sealed gas from escaping through faults or cracks.

[0016] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention discloses a CCUS experimental device and method for carbon dioxide flooding and storage. The device comprises: a three-dimensional reservoir physical model, a fluid injection system, a resistivity monitoring system, a distributed optical fiber monitoring system, a fluid collection and metering system, a development well pattern system, and a fluid migration observation system. The three-dimensional reservoir physical model is used to construct a simulated formation, and a development well pattern system is installed on the simulated formation; the development well system includes injection wells and production wells; a fluid injection system is connected to the injection well and is used to inject a salt solution of a specified concentration of the target reservoir into the simulated formation to simulate formation water, as well as a 1,8-naphthalene imide-based fluorescent dye fully dissolved in supercritical carbon dioxide; a fluid collection and metering system is connected to the production well and is used to collect and calculate the volume of produced oil; a resistivity monitoring system is set at multiple monitoring points on the simulated formation to monitor the fluid saturation distribution in the simulated formation; a fluid migration observation system is used to observe the migration path of supercritical carbon dioxide in the three-dimensional reservoir physical model; and a distributed optical fiber monitoring system is set in the simulated formation to transmit the emitted optical signal to each formation, and use the received optical signal to calculate the strain and draw a strain field map of the storage layer. The present invention can realize water injection production of the reservoir, as well as CO2 injection oil recovery and CO2 storage stability simulation experiments in the later stage of development. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the CCUS experimental device structure of the present invention; Figure 2 It is a side view of the device in this embodiment.

[0019] Reference numerals: 1. Formation water bottle; 2. Simulated oil bottle; 3. Formation water intermediate container; 4. Simulated oil intermediate container; 5. Double-rod constant pressure pump; 6. 1,8-naphthalimide fluorescent dye bottle; 7. First valve; 8. Supercritical carbon dioxide bottle; 9. Supercritical carbon dioxide intermediate container; 10. Six-way valve; 11. First gas flow meter; 12. Pressure patrol meter; 13. First fiber optic coupler; 14. Optical signal transmitter; 15. Saturation data processing system; 16. Injection well; 17. High-resolution camera; 18. Visual observation window; 19. Resistivity sensor; 20. Optical transparent window; 21. 3D reservoir model; 22. Constant temperature box; 23. Production Well; 24. Distributed optical fiber; 25. Image processing and analysis system; 26. Optical signal receiver; 27. Second valve; 28. Back pressure pump; 29. First pressure gauge; 30. Fluid collection device; 31. Third valve; 32. Second gas flow meter; 33. Second pressure gauge; 34. Vacuum pump; 35. Gas collection device; 36. Optical signal processing and analysis system; 37. Temperature gauge; 38. Second optical fiber coupler; 39. Bracket; 40. Resistivity probe; 41. Slidable bracket; 42. Back pressure valve; 43. Third pressure gauge; 44. Pressure test point; 45. Confining pressure pump; 46. Fluid migration front; 47. Fracture; 48. Cave. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The purpose of the present invention is to provide a CCUS experimental device and method for carbon dioxide recovery and storage, aiming to solve or improve at least one of the above-mentioned technical problems.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-Figure 2 As shown, the present invention provides a CCUS experimental device for carbon dioxide recovery and storage, including: a three-dimensional reservoir physical model, a fluid injection system, a resistivity monitoring system, a distributed optical fiber monitoring system, a fluid collection and metering system, a development well pattern system and a fluid migration observation system.

[0024] A three-dimensional reservoir physical model is used to construct a simulated formation, and a development well pattern system is installed on the simulated formation; the development well pattern system includes an injection well 16 and a production well 23.

[0025] A fluid injection system is connected to the injection well 16 and is used to inject a salt solution simulating formation water of a specified concentration of a target oil reservoir and a 1,8-naphthaleneimide-based fluorescent dye fully dissolved in supercritical carbon dioxide into the simulated formation.

[0026] A fluid collection and metering system is connected to the production well 23 and is used to collect and calculate the volume of produced oil.

[0027] A resistivity monitoring system is provided with a plurality of monitoring points on the simulated formation for monitoring the distribution of fluid saturation in the simulated formation.

[0028] A fluid migration observation system is used to observe the migration path of supercritical carbon dioxide in the three-dimensional reservoir physical model.

[0029] A distributed optical fiber monitoring system is provided in the simulated stratum, and is used to transmit the emitted optical signals to each stratum, and calculate the strain using the received optical signals to draw a strain field map of the sealing stratum.

[0030] As a specific implementation method, the three-dimensional reservoir physical model specifically includes: a pressure patrol meter 12, a three-dimensional reservoir model 21, a constant temperature box 22 and a temperature meter 37; the three-dimensional reservoir model 21 is arranged inside the constant temperature box 22 for constructing a simulated formation; the constant temperature box 22 is used to maintain the formation temperature; the temperature meter 37 is arranged on the constant temperature box 22 for adjusting the temperature of the constant temperature box 22; the pressure patrol meter 12 is arranged at the pressure test point 44 of the simulated formation for monitoring the formation pressure.

[0031] As a specific embodiment, the fluid injection system specifically includes: a formation water bottle 1, a simulated oil bottle 2, a formation water intermediate container 3, a simulated oil intermediate container 4, a double-rod constant pressure pump 5, a 1,8-naphthaleneimide fluorescent dye bottle 6, a first valve 7, a supercritical carbon dioxide bottle 8, a supercritical carbon dioxide intermediate container 9, a six-way valve 10, a first gas flow meter 11, a bracket 39 and a third pressure gauge 43.

[0032] The output end of the formation water bottle 1 is connected to the input end of the formation water intermediate container 3 and the double-rod constant pressure pump 5 respectively; the output end of the simulated oil bottle 2 is connected to the simulated oil intermediate container 4 and the input end of the double-rod constant pressure pump 5 respectively; the 1,8-naphthaleneimide fluorescent dye bottle 6, the supercritical carbon dioxide bottle 8 set on the bracket 39 and the supercritical carbon dioxide intermediate container 9 are connected in sequence, and the connecting pipeline between the 1,8-naphthaleneimide fluorescent dye bottle 6 and the supercritical carbon dioxide bottle 8 is also provided with a The first valve 7; the output end of the double-rod constant pressure pump 5 is also connected to the input end of the supercritical carbon dioxide intermediate container 9; the output end of the supercritical carbon dioxide intermediate container 9 is connected to the input end of the first gas flowmeter 11; the output ends of the formation water intermediate container 3, the simulated oil intermediate container 4 and the first gas flowmeter 11 are all connected to the six-way valve 10; the six-way valve 10 is also connected to the injection well 16, and the third pressure gauge 43 is also provided on the connecting pipeline between the six-way valve 10 and the injection well 16.

[0033] As a specific embodiment, the fluid collection and metering system specifically includes: a second valve 27, a back pressure pump 28, a first pressure gauge 29, a fluid collection device 30, a third valve 31, a second gas flow meter 32, a second pressure gauge 33, a vacuum pump 34, a gas collection device 35 and a back pressure valve 42.

[0034] The production well 23 is connected to the second valve 27 through a first branch, and the production well 23 is connected to the third valve 31 through a second branch; the second valve 27 is also connected to the first pressure gauge 29; the first pressure gauge 29 is connected to the back pressure pump 28 through a first connecting pipeline, and the back pressure valve 42 is also installed on the first connecting pipeline; the first pressure gauge 29 is connected to the fluid collection device 30 through a second connecting pipeline; the fluid collection device 30 is also connected to the second gas flow meter 32 and the gas collection device 35 in sequence; the third valve 31 is also connected to the vacuum pump 34, and the second pressure gauge 33 is also provided on the connecting pipeline between the third valve 31 and the vacuum pump 34.

[0035] As a specific implementation, the resistivity monitoring system specifically includes: a saturation data processing system 15 , a resistivity sensor 19 and a plurality of resistivity probes 40 .

[0036] Each of the resistivity probes 40 is disposed in a predetermined arrangement within the simulated formation, and each of the resistivity probes 40 is connected to the resistivity sensor 19 ; the resistivity sensor 19 is also connected to the saturation data processing system 15 .

[0037] As a specific embodiment, the fluid migration observation system specifically includes: a high-resolution camera 17 , a visualization observation window 18 , an optically transparent window 20 , an image processing and analysis system 25 , and a slidable bracket 41 .

[0038] The optically transparent window 20 is arranged on one side of the three-dimensional reservoir physical model, and the high-resolution camera 17 is installed on the slidable bracket 41 and is arranged on the other side of the three-dimensional reservoir physical model relative to the optically transparent window 20; the high-resolution camera 17 is also connected to the image processing and analysis system 25; the visual observation window 18 is opened on at least one side of the three-dimensional reservoir physical model.

[0039] As a specific implementation, the distributed optical fiber monitoring system specifically includes: a first optical fiber coupler 13, an optical signal transmitter 14, a distributed optical fiber 24, an optical signal receiver 26, an optical signal processing and analysis system 36 and a second optical fiber coupler 38.

[0040] The optical signal transmitter 14, the first optical fiber coupler 13 and one end of the distributed optical fiber 24 are connected in sequence, and the other end of the distributed optical fiber 24 is also connected in sequence to the second optical fiber coupler 38, the optical signal receiver 26 and the optical signal processing and analysis system 36.

[0041] The device provided in this example is designed to enable water injection recovery of oil reservoirs, as well as simulation experiments of CO2 injection for oil recovery and CO2 storage stability in later stages of development. This device can directly observe the diffusion and oil recovery process of CO2 in the reservoir, monitor the resistivity of various points in the reservoir, and calculate and analyze changes in fluid saturation through resistivity changes. It can also monitor formation strain caused by CO2 injection in real time, quantify CO2 storage volume, and calculate recovery factors for different extraction methods. Adjusting parameters such as injection pressure, temperature, and flow rate facilitates the study of CO2-EOR effects under different conditions, comprehensively demonstrating the physical phenomena and technical details of the CCUS process, and is of great significance to scientific research.

[0042] To achieve the above objectives, the present invention provides a CO2 injection flooding and storage simulation experimental device, comprising a three-dimensional reservoir physical model, a fluid injection system, a resistivity monitoring system, a distributed fiber optic monitoring system, a fluid collection and metering system, a development well pattern system, and a fluid migration observation system. Using a molecularly modified 1,8-naphthalimide-based fluorescent dye labeled with supercritical carbon dioxide, an observation window and a high-resolution camera 17 allow for real-time visualization of fluid distribution and the oil and gas migration front. The high-resolution camera 17 captures and records the migration path of the CO2 front, analyzing the CO2 front's advance velocity and remaining oil distribution characteristics through sequential images. A resistivity probe 40, installed within the three-dimensional reservoir physical model, monitors the resistivity of each reservoir point in real time. The data is transmitted to a computer via a resistivity sensor 19 for analysis and calculation of fluid saturation. The calculated water saturation data is combined with other formation parameters (such as depth and porosity) to create a fluid saturation map, which clearly displays the fluid saturation distribution within different formations. By deploying distributed optical fibers 24 within the reservoir physical model, the real-time optical signals transmitted to each formation are then transmitted to a computer. This allows calculation of formation strain caused by CO2 injection, mapping the strain field in the storage layer, and verifying the geological stability of long-term CO2 storage. The storage volume is calculated by the difference in CO2 gas flowmeter readings during injection and production. A comparative analysis of the recovery rate improvements achieved under three development methods—depletion recovery, water flooding, and CO2 flooding—demonstrates the unique advantages of supercritical CO2 miscible flooding in the development of unconventional oil and gas reservoirs.

[0043] In addition, the present invention also provides a CCUS experimental method for carbon dioxide flooding and storage, which is applied to the above-mentioned device, comprising: Based on the CCUS experimental device, a simulated formation is constructed according to the physical parameters and reservoir characteristic parameters of the target oil reservoir, and the simulated formation is used to carry out reservoir depletion recovery, water injection and CO2 injection to monitor the stability of CO2 storage. The reservoir depletion recovery process includes: opening a production well 23 in the three-dimensional reservoir physical model until no more oil is produced in the fluid collection and metering system, and then calculating the produced oil volume.

[0044] As a specific implementation method, based on the above CCUS experimental device, the following implementation process is provided.

[0045] 1. Constructing a 3D reservoir physical model 1.1 Sand Filling the 3D Reservoir Physical Model. Based on the physical parameters of the target reservoir and the reservoir characteristics, simulated formation sand bodies are added to the interior of the rectangular box. During the sand filling process, distributed optical fibers 24 are embedded in each simulated formation layer. Visual observation windows 18 are installed on the sidewalls of the reservoir model. The development well pattern system and resistivity probes 40 are laid at designated locations. A confining pressure pump 45 is also installed outside the simulated formation.

[0046] 1.2 Solution Preparation. Prepare a saline solution of the specified concentration for the target reservoir to simulate formation water. Inject the molecularly designed 1,8-naphthalimide-based fluorescent dye into the supercritical CO2 bottle 8. Shake the supercritical CO2 container for 2 hours while injecting to ensure full dissolution of the fluorescent dye in the supercritical CO2.

[0047] 1.3 Installing High-Resolution Camera 17 and Optically Transparent Window 20. Mount high-resolution camera 17 on slidable bracket 41 and adjust the position of optically transparent window 20 so that it faces high-resolution camera 17. Placing optically transparent window 20 directly opposite high-resolution camera 17 improves the optical system's light transmittance, ensures optical path symmetry and arch axis alignment, and thus reduces imaging errors.

[0048] 1.4 Adjust the temperature of the 3D reservoir physical model. Open the thermostat 22, observe the reading on the temperature gauge 37, and adjust it to the target experimental temperature.

[0049] 2. Construct the irreducible water state of the reservoir.

[0050] 2.1 Saturating the 3D Reservoir Model 21 with Formation Water. Vacuum the 3D reservoir model 21 with vacuum pump 34, then close the vacuum pump. Open the switches of the formation water bottle 1, the formation water intermediate container 3, and the corresponding six-way valve 10. Start the double-rod constant pressure pump 5 and inject formation water through the injection well 16. When the pressure probe 12 reading stabilizes at 15 MPa, indicating that the 3D reservoir physical model is saturated with formation water, close the corresponding six-way valve 10, the formation water bottle 1, the formation water intermediate container 3, and the double-rod constant pressure pump 5.

[0051] 2.2 Turn on the switches of simulated oil bottle 2, simulated oil intermediate container 4, and the corresponding six-way valve 10. Start the double-rod constant pressure pump 5 and inject simulated oil through injection well 16. Open production well 23 until no formation water is produced from the fluid collection device 30. Close production well 23 and record the volume of produced water. When the pressure inspection instrument 12 reading stabilizes at 15 MPa, close the switches of injection well 16, simulated oil bottle 2, and simulated oil intermediate container 4.

[0052] 3. Simulate reservoir depletion production.

[0053] 3.1 Open the production well 23 until the fluid collection device 30 stops producing oil and the first pressure gauge 29 reads 7 MPa and stabilizes. Then close the production well 23 and record the produced oil volume. .

[0054] 4 Water injection to increase oil recovery.

[0055] 4.1 Open the switches of the formation water bottle 1, the formation water intermediate container 3 and the corresponding six-way valve 10, start the double-rod constant pressure pump 5, and Inject formation water through injection well 16. Open production well 23 until no more oil is produced at the outlet. Close the corresponding injection six-way valve 10, formation water bottle 1, formation water intermediate container 3, and double-rod constant pressure pump 5, and record the produced oil volume. .

[0056] 4.2 Fluid Saturation Monitoring. During the waterflooding process, resistivity probe 40 data is collected every ten minutes. Fluid saturation is measured based on resistivity and a fluid saturation map is drawn to monitor the distribution of fluid saturation in the formation.

[0057] 4.3 Formation Pressure Monitoring. Using a pressure patrol meter 12, changes in formation pressure during water injection are monitored in real time. This allows for accurate assessment of the dynamic balance between injection and production volumes, preventing formation energy deficits caused by crude oil extraction, identifying water injection anomalies, and preventing formation damage, providing basic parameters for CO2 flooding implementation.

[0058] 5. Inject CO2 to increase oil recovery.

[0059] 5.1 Open the switch of supercritical carbon dioxide bottle 8, the switch of supercritical carbon dioxide intermediate container 9 and the corresponding pipeline valve. Open the double-rod constant pressure pump 5 at 0.1 Inject supercritical carbon dioxide through the injection well 16, open the production well 23, and close the production well 23 until there is no more oil production from the fluid collection device 30, and record the volume of produced oil. Close the switches of the supercritical carbon dioxide bottle 8, the supercritical carbon dioxide intermediate container 9, the corresponding pipeline valves, and the double-rod constant pressure pump 5, and record the volume of CO2 injected and the volume of CO2 produced .

[0060] 5.2 Observing the Supercritical Carbon Dioxide Flooding Front. During supercritical carbon dioxide flooding, a high-resolution camera was used to capture the CO2 flooding fluid migration front in real time46. The displacement process was captured with millisecond exposure times to capture the CO2 front migration path. The CO2 front advancement velocity and remaining oil distribution characteristics were analyzed using sequential images. The image processing and analysis system25 converted the grayscale images into pseudo-color concentration distribution maps to quantify the CO2 sweep efficiency and verify the microscopic seepage patterns. The migration path of CO2 in complex pores was directly observed through the visual observation window18, allowing real-time monitoring of the displacement front. The high-resolution camera can be any commercially available camera that meets the high-resolution threshold requirements.

[0061] 5.3 Monitoring Fluid Saturation. During supercritical CO2 flooding, resistivity probe 40 data is collected every ten minutes. Fluid saturation is measured based on resistivity and a fluid saturation map is drawn to monitor the distribution of fluid saturation in the formation.

[0062] 5.4 Formation Pressure Monitoring: Real-time monitoring of formation pressure using a pressure patrol instrument 12 maintains miscible displacement pressure conditions to ensure storage safety and oil recovery efficiency.

[0063] 5.5 Calculate crude oil recovery.

[0064] Based on the above recovery simulation processes of reservoir depletion production, water flooding and CO2 flooding, the recovery factors for each stage are calculated as shown below.

[0065] Depletion mining recovery rate: , Water flooding oil recovery rate: , CO2 flooding recovery rate: , in, The recovery rate is depletion mining; The recovery factor is water flooding; is the CO2 recovery rate, is the recoverable oil volume, ; is the oil production volume of depletion recovery, ; is the water flooding oil production volume, ; is the oil production volume of CO2 flooding, .

[0066] 6. Monitor CO2 storage stability.

[0067] 6.1 Monitoring formation strain using distributed optical fiber 24. During supercritical CO2 injection, the optical fiber optical signal transmitter 14 is simultaneously activated to transmit optical signals to each formation. The optical signal is received by the optical signal receiver 26 and transmitted to the optical signal processing and analysis system 36. Strain is calculated using the following formula, and a strain field map of the storage layer is drawn. This allows for real-time monitoring and control of gas crossover risks and verification of the geological stability of the CO2 storage: , in, is the average wavelength, is the wavelength shift, is the average optical frequency, is the optical frequency shift, is the strain sensitivity coefficient, is the optical fiber strain, is the temperature sensitivity coefficient, For temperature changes.

[0068] 6.2 Calculate the amount of carbon dioxide stored.

[0069] , in, is the CO2 injection amount, ; is the CO2 output, ; is the CO2 storage capacity, .

[0070] 6.3 Observing the migration and distribution of supercritical CO2. A high-resolution camera 17 continuously captures the fluorescence of supercritical CO2, recording time-series images. The image processing and analysis system 25 converts the fluorescence intensity into a pseudo-color image of CO2 concentration, identifying CO2 retention characteristics in low-permeability areas and rapid migration in high-permeability channels. The migration and diffusion paths of CO2 are directly observed through the visualization observation window 18. By combining fluorescent labeling with high-resolution imaging and visualization windows, visual monitoring of CO2 diffusion and migration during oil recovery is achieved, providing accurate data support for carbon sequestration.

[0071] 6.4 Formation Pressure Monitoring. Formation pressure is monitored using a pressure patrol instrument 12. Real-time monitoring of formation pressure prevents formation rupture or CO2 leakage caused by pressure buildup, preventing the escape of stored gas through faults or cracks 47, thereby ensuring the safety of the storage environment. The simulated bottom layer also contains caves 48.

[0072] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A CCUS experimental device for carbon dioxide flooding and storage, characterized in that: include: A three-dimensional reservoir physical model, wherein the three-dimensional reservoir physical model is used to construct a simulated formation, and a development well pattern system is installed on the simulated formation; the development well pattern system includes an injection well (16) and a production well (23); A fluid injection system connected to the injection well (16) for injecting a salt solution simulating formation water of a specified concentration of a target oil reservoir and a 1,8-naphthaleneimide-based fluorescent dye fully dissolved in supercritical carbon dioxide into the simulated formation; A fluid collection and metering system, connected to the production well (23), for collecting and calculating the volume of produced oil; a resistivity monitoring system, wherein the resistivity monitoring system is provided with a plurality of monitoring points on the simulated formation for monitoring the distribution of fluid saturation in the simulated formation; a fluid migration observation system, the fluid migration observation system being used to observe the migration path of supercritical carbon dioxide in the three-dimensional reservoir physical model; A distributed optical fiber monitoring system is provided in the simulated stratum, and is used to transmit the emitted optical signals to each stratum, and calculate the strain using the received optical signals to draw a strain field map of the sealing stratum.

2. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The three-dimensional reservoir physical model specifically includes: a pressure patrol meter (12), a three-dimensional reservoir model (21), a constant temperature box (22) and a temperature meter (37); the three-dimensional reservoir model (21) is arranged inside the constant temperature box (22) for constructing a simulated formation; the constant temperature box (22) is used to maintain the formation temperature; the temperature meter (37) is arranged on the constant temperature box (22) for adjusting the temperature of the constant temperature box (22); the pressure patrol meter (12) is arranged at a pressure test point (44) of the simulated formation for monitoring the formation pressure.

3. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The fluid injection system specifically comprises: a formation water bottle (1), a simulated oil bottle (2), a formation water intermediate container (3), a simulated oil intermediate container (4), a double-rod constant pressure pump (5), a 1,8-naphthaleneimide fluorescent dye bottle, a first valve (7), a supercritical carbon dioxide bottle (8), a supercritical carbon dioxide intermediate container (9), a six-way valve (10), a first gas flow meter (11), a bracket (39) and a third pressure gauge (43); The output end of the formation water bottle (1) is connected to the input end of the formation water intermediate container (3) and the double-rod constant pressure pump (5) respectively; the output end of the simulated oil bottle (2) is connected to the input end of the simulated oil intermediate container (4) and the double-rod constant pressure pump (5) respectively; The 1,8-naphthaleneimide fluorescent dye bottle (6), the supercritical carbon dioxide bottle (8) arranged on the bracket (39), and the supercritical carbon dioxide intermediate container (9) are connected in sequence, and the first valve (7) is also provided on the connecting pipeline between the 1,8-naphthaleneimide fluorescent dye bottle (6) and the supercritical carbon dioxide bottle (8); the output end of the double-rod constant pressure pump (5) is also connected to the input end of the supercritical carbon dioxide intermediate container (9); the output end of the supercritical carbon dioxide intermediate container (9) is connected to the input end of the first gas flow meter (11); the output ends of the formation water intermediate container (3), the simulated oil intermediate container (4), and the first gas flow meter (11) are all connected to the six-way valve (10); the six-way valve (10) is also connected to the injection well (16), and the third pressure gauge (43) is also provided on the connecting pipeline between the six-way valve (10) and the injection well (16).

4. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The fluid collection and metering system specifically comprises: a second valve (27), a back pressure pump (28), a first pressure gauge (29), a fluid collection device (30), a third valve (31), a second gas flow meter (32), a second pressure gauge (33), a vacuum pump (34), a gas collection device (35) and a back pressure valve (42); The production well (23) is connected to the second valve (27) through a first branch, and the production well (23) is connected to the third valve (31) through a second branch; the second valve (27) is also connected to the first pressure gauge (29); the first pressure gauge (29) is connected to the back pressure pump (28) through a first connecting pipeline, and the back pressure valve (42) is also installed on the first connecting pipeline; the first pressure gauge (29) is connected to the fluid collecting device (30) through a second connecting pipeline; the fluid collecting device (30) is also connected to the second gas flow meter (32) and the gas collecting device (35) in sequence; the third valve (31) is also connected to the vacuum pump (34), and the second pressure gauge (33) is also provided on the connecting pipeline between the third valve (31) and the vacuum pump (34).

5. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The resistivity monitoring system specifically comprises: a saturation data processing system (15), a resistivity sensor (19) and a plurality of resistivity probes (40); Each of the resistivity probes (40) is arranged in a set arrangement within the simulated formation, and each of the resistivity probes (40) is connected to the resistivity sensor (19); the resistivity sensor (19) is also connected to the saturation data processing system (15).

6. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The fluid migration observation system specifically comprises: a high-resolution camera (17), a visual observation window (18), an optically transparent window (20), an image processing and analysis system (25), and a slidable bracket (41); The optically transparent window (20) is arranged on one side of the three-dimensional reservoir physical model, and the high-resolution camera (17) is installed on the slidable bracket (41) and is arranged on the other side of the three-dimensional reservoir physical model relative to the optically transparent window (20); the high-resolution camera (17) is also connected to the image processing and analysis system (25); and the visual observation window (18) is opened on at least one side of the three-dimensional reservoir physical model.

7. The CCUS experimental device for carbon dioxide flooding and storage according to claim 1, characterized in that: The distributed optical fiber monitoring system specifically comprises: a first optical fiber coupler (13), an optical signal transmitter (14), a distributed optical fiber (24), an optical signal receiver (26), an optical signal processing and analysis system (36), and a second optical fiber coupler (38); The optical signal transmitter (14), the first optical fiber coupler (13), and one end of the distributed optical fiber (24) are connected in sequence, and the other end of the distributed optical fiber (24) is also connected in sequence to the second optical fiber coupler (38), the optical signal receiver (26), and the optical signal processing and analysis system (36).

8. A CCUS experimental method for carbon dioxide flooding and storage, applied to the apparatus according to any one of claims 1 to 7, characterized in that: include: Based on the CCUS experimental device, a simulated formation is constructed according to the physical parameters and reservoir characteristic parameters of the target oil reservoir, and the simulated formation is used to carry out oil reservoir depletion production, water injection and CO2 injection to monitor the stability of CO2 storage; wherein, the process of oil reservoir depletion production includes: opening a production well (23) in the three-dimensional oil reservoir physical model until no more oil is produced in the fluid collection and metering system, and calculating the produced oil volume.

9. The CCUS experimental method for carbon dioxide flooding and storage according to claim 8, characterized in that: The processes of water flooding and CO2 flooding both include monitoring of fluid saturation and formation pressure; The water injection oil displacement process specifically includes: 0.1 Inject formation water through the injection well (16), open the production well (23), and calculate the volume of produced oil when no more oil is produced in the fluid collection and metering system; During the water injection process, data from the resistivity probe (40) is collected every ten minutes, the fluid saturation is measured based on the resistivity and a fluid saturation map is drawn to monitor the distribution of fluid saturation in the formation, and the pressure patrol meter (12) is used to monitor the formation pressure changes in real time during the water injection process; The CO2 injection flooding process specifically includes: 0.1 Injecting supercritical carbon dioxide through the injection well (16), opening the production well (23), and calculating the volume of produced oil when no more oil is produced in the fluid collection and metering system; During the supercritical carbon dioxide flooding process, the fluid migration observation system is used to observe and photograph the supercritical carbon dioxide flooding front and the migration path of carbon dioxide in complex pores, and resistivity probe (40) data is collected every ten minutes. The fluid saturation is measured based on the resistivity and a fluid saturation map is drawn to monitor the fluid saturation distribution in the formation, and the pressure patrol meter (12) is used to monitor the formation pressure changes in real time during the water injection process.

10. The CCUS experimental method for carbon dioxide flooding and storage according to claim 8, characterized in that: The process of CO2 storage stability monitoring includes: The distributed optical fiber monitoring system is used to calculate the formation strain and draw a strain field map of the storage layer. The calculation formula of the formation strain is: ， in, is the average wavelength, is the wavelength shift, is the average optical frequency, is the optical frequency shift, is the strain sensitivity coefficient, is the optical fiber strain, is the temperature sensitivity coefficient, is temperature change; Calculate the amount of CO2 stored: ， in, is the CO2 injection amount, ; is the CO2 output, ; is the CO2 storage capacity, ; A high-resolution camera (17) is used to continuously photograph the fluorescence of supercritical CO2 and record time series images. The fluorescence intensity is converted into a pseudo-color image of CO2 concentration through an image processing and analysis system (25). The retention characteristics of CO2 in low-permeability areas and the rapid migration phenomenon in high-permeability channels are identified, thus realizing the visual monitoring of CO2 diffusion and migration during the CO2 flooding process. The formation pressure is monitored by a pressure patrol meter (12). Real-time monitoring of the formation pressure prevents formation rupture or carbon dioxide leakage caused by pressure accumulation, and prevents the sealed gas from escaping through faults or cracks (47).

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