A CO2 dynamic dissolution testing device

Abstract

This invention provides a CO2 dynamic dissolution testing device. The device includes: a core holder, a vacuum system, a confining pressure system, a back pressure system, a fluid supply system, a nuclear magnetic resonance (NMR) testing system, a sensor system, and a temperature control system. The fluid supply system includes a CO2 gas supply component, a formation water supply component, a saturated carbon dioxide formation water supply component, and a helium supply component. The helium supply component includes a helium cylinder and a standard gas chamber, with the gas outlet of the helium cylinder connected to the inlet of the standard gas chamber. The CO2 gas supply component, formation water supply component, saturated carbon dioxide formation water supply component, and standard gas chamber are each connected to the fluid inlet of the core holder. The sensor system includes a pressure sensor group, comprising a pressure sensor for acquiring the pressure at the fluid inlet of the core holder, a pressure sensor for acquiring the pressure at the fluid outlet of the core holder, and a pressure sensor for acquiring the pressure of the standard gas chamber.

Description

Technical Field

[0001] This invention belongs to the field of unconventional oil and gas development technology and relates to a CO2 dynamic dissolution testing device. Background Technology

[0002] CO2 huff and puff technology can effectively replenish formation energy, thereby extending the depletion recovery period after fracturing in tight oil reservoirs and improving oil recovery. However, tight reservoirs have high water saturation. When CO2 is injected into the formation, it reacts with formation water to produce carbonic acid. This carbonic acid interacts with the reservoir matrix minerals in a physicochemical manner: on the one hand, it dissolves the minerals on the pore throat walls, increasing pore space and having a certain microscopic reservoir modification effect, thus improving fluid permeability; on the other hand, clay minerals are prone to swelling, dispersion, and migration when exposed to water, resulting in severe reservoir water sensitivity, and clay particles can further clog small pore throats. The mineral dissolution and redeposition caused by CO2 dissolution affect the pore throat characteristics of porous media and further affect multiphase flow in tight reservoirs.

[0003] Currently, characterizing the physical properties of dissolved core samples requires a rather cumbersome testing process, and uncertainties along the way often lead to test failures or excessively large errors in the test results. Traditional CO2 dissolution testing of core samples usually requires the use of multiple instruments to test the porosity, permeability, and pore size distribution of the dissolved core separately. It is impossible to achieve integrated testing of porosity, permeability, and pore size distribution, and it is impossible to detect changes in the physical properties of the dissolved core in real time. Furthermore, the data testing cycle is long, and the test data is easily affected by environmental and human factors, and the test data cannot reflect the real-time changes of the dissolved core well. In summary, the existing CO2 dissolution testing technology for core samples has many problems: (1) It requires testing different physical properties of core samples individually, which is cumbersome and has a long testing cycle; (2) It requires a lot of manual operation and intervention, resulting in large errors and uncertainties, and unreliable results; (3) It requires multiple devices to complete different measurements, dispersing the data of different parameters in different devices and files, lacking integration, increasing the complexity of data integration and analysis, and increasing experimental costs.

[0004] In summary, the small pore throats and poor multiphase flow capacity of tight reservoir matrix increase the difficulty of multiphase flow experiments in tight cores. Currently, research on CO2 dissolution characteristics and multiphase flow in tight reservoirs is scarce. Advanced technologies such as X-ray CT scanning and nuclear magnetic resonance still have limitations in the application of tight oil, failing to accurately characterize the physical properties of tight reservoirs. Their equipment parameters cannot meet the conditions of tight oil reservoirs, experimental costs are high, and the testing of various physical properties of tight cores is relatively fragmented.

[0005] Therefore, there is still a need to study new CO2 dissolution testing technologies for tight reservoirs that can simply and accurately monitor the porosity, gas permeability, and pore size distribution of dissolved cores under target temperature and pressure conditions in an integrated manner, so as to reduce the impact of human error and uncertainties caused by frequent core movement. Summary of the Invention

[0006] The purpose of this invention is to provide a technical solution that can effectively determine the dynamic dissolution porosity, permeability, and pore size distribution characteristics of tight reservoirs under target temperature and pressure conditions.

[0007] To achieve the above objectives, the present invention provides a CO2 dynamic dissolution testing device, wherein the device includes: a core holder, a vacuum system, a confining pressure system, a back pressure system, a fluid supply system, a nuclear magnetic resonance testing system, a sensor system, and a temperature control system;

[0008] The fluid supply system includes a CO2 gas supply component, a formation water supply component, a saturated carbon dioxide formation water supply component, and a helium supply component. The helium supply component includes a helium cylinder and a standard gas chamber, with the gas outlet of the helium cylinder connected to the gas inlet of the standard gas chamber. The CO2 gas supply component, formation water supply component, saturated carbon dioxide formation water supply component, and standard gas chamber are respectively connected to the fluid inlet of the core holder to inject CO2 gas, formation water, saturated carbon dioxide formation water, and helium into the core sample placed in the core holder.

[0009] The nuclear magnetic resonance (NMR) testing system is used to perform NMR testing on core samples placed in a core holder. The sensor system includes a pressure sensor group, comprising a pressure sensor for acquiring the pressure at the fluid inlet of the core holder, a pressure sensor for acquiring the pressure at the fluid outlet of the core holder, and a pressure sensor for acquiring the pressure in the standard gas chamber. A confining pressure system is connected to the confining pressure port of the core holder to provide confining pressure. A back pressure system is connected to the fluid outlet of the core holder to provide back pressure. A vacuum system is connected to the vent port of the core holder to achieve vacuuming of the core sample placed in the core holder. A temperature control system is used to provide a suitable temperature for the core holder.

[0010] According to the specific implementation of the CO2 dynamic dissolution test equipment, preferably, the CO2 gas supply component includes a CO2 gas cylinder, the formation water supply component includes a formation water storage container, and the saturated carbon dioxide formation water supply component includes a saturated carbon dioxide formation water storage container.

[0011] More preferably, the formation water storage container is a piston-type intermediate container, and the saturated carbon dioxide formation water storage container is a piston-type intermediate container; the formation water supply assembly also includes a first ISCO pump and a first pumping medium storage tank, the saturated carbon dioxide formation water supply assembly also includes a second ISCO pump and a second pumping medium storage tank, and the CO2 gas supply assembly also includes a booster pump; the fluid outlet of the first pumping medium storage tank is connected to the inlet of the first ISCO pump, the outlet of the first ISCO pump is connected to the bottom fluid port of the formation water storage container, the fluid outlet of the second pumping medium storage tank is connected to the inlet of the second ISCO pump, the outlet of the second ISCO pump is connected to the bottom fluid port of the saturated carbon dioxide formation water storage container, the booster pump is located at the outlet of the CO2 gas cylinder, the top fluid port of the formation water storage container is connected to the fluid inlet of the core holder, and the top fluid port of the saturated carbon dioxide formation water storage container is connected to the fluid inlet of the core holder;

[0012] More preferably, the CO2 cylinder is also connected to a saturated carbon dioxide formation water storage container to provide CO2 gas to the saturated carbon dioxide formation water storage container for the preparation of saturated carbon dioxide formation water.

[0013] More preferably, the formation water storage container is also connected to a saturated carbon dioxide formation water storage container to provide formation water to the saturated carbon dioxide formation water storage container for the preparation of saturated carbon dioxide formation water.

[0014] According to the specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the confining pressure system includes a confining pressure pump, which is connected to the confining pressure port of the core holder to realize the connection between the confining pressure system and the confining pressure port of the core holder.

[0015] The confining pressure system can maintain high pressure conditions to simulate underground reservoir conditions.

[0016] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the back pressure system includes a back pressure pump and a back pressure valve connected in sequence, and the outlet of the back pressure valve is connected to the fluid outlet of the core holder, thereby realizing the connection between the back pressure system and the fluid outlet of the core holder.

[0017] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the sensor system further includes a temperature sensor to obtain the temperature of the core sample set in the core holder.

[0018] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the pressure sensor group further includes a pressure sensor for obtaining the confining pressure of the core holder and a pressure sensor for obtaining the back pressure of the core holder.

[0019] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the CO2 dynamic dissolution testing equipment also includes a gas-liquid separator, which is connected to the fluid outlet of the core holder and is used to separate the fluid and liquid extracted from the core holder so as to collect and analyze data in the experiment.

[0020] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the nuclear magnetic resonance testing system includes a nuclear magnetic resonance (NMR) probe located near the core sample, which includes a magnetic field and a transceiver antenna for exciting nuclear magnetic resonance signals and receiving feedback signals.

[0021] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the CO2 dynamic dissolution testing equipment further includes a fluid control system. The fluid control system includes a CO2 gas control valve installed on the connecting pipeline between the CO2 gas cylinder and the fluid inlet of the core holder to control the flow rate of CO2 gas injected into the core holder; a formation water control valve installed on the connecting pipeline between the formation water storage container and the fluid inlet of the core holder to control the flow rate of formation water injected into the core holder; and a saturated carbon dioxide formation water storage container... The following valves are included: a saturated carbon dioxide formation water control valve on the connecting pipeline between the storage container and the fluid inlet of the core holder to control the flow rate of saturated carbon dioxide formation water injected into the core holder; a helium control valve on the connecting pipeline between the standard gas chamber and the fluid inlet of the core holder to control the flow rate of helium injected into the core holder; a core holder inlet control valve at the fluid inlet of the core holder; a core holder outlet control valve at the fluid outlet of the core holder; and a venting control valve at the venting port of the core holder.

[0022] In this preferred technical solution, the fluid control system can precisely control the flow rate, pressure, and supply speed of the fluid to ensure the accuracy and repeatability of experimental parameters. The fluid control system has adjustment capabilities and can simulate different fluid media. By using the fluid control system in conjunction with the sensor system, fluid properties such as temperature, pressure, and flow rate can be monitored and adjusted in real time to ensure the controllability of the experiment, provide a high-quality fluid supply, and ensure the reliability and accuracy of experimental data.

[0023] According to a specific implementation of the CO2 dynamic dissolution testing equipment, preferably, the CO2 dynamic dissolution testing equipment also includes an experimental control and data processing system; the experimental control and data processing system is connected to the power unit and each control valve in the CO2 dynamic dissolution testing equipment, and is used to regulate the operation of the power unit and each control valve according to the set program, complete the CO2 dynamic dissolution testing experiment, and determine the porosity, carbon dioxide-water two-phase flow phase permeation curve and pore size distribution of the core sample during the CO2 dynamic dissolution process;

[0024] In this preferred technical solution, the experimental control and data processing system can be connected to a computer;

[0025] More preferably, the experimental control and data processing system is capable of executing the first porosity test procedure:

[0026] 1) Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to subsequent steps 2)-5) under the applied confining pressure conditions;

[0027] 2) Open the venting control valve, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder;

[0028] 3) After the vacuuming is completed, open the helium control valve, close the other control valves, and start the helium cylinder to inject a certain amount of helium into the standard gas chamber;

[0029] 4) After helium injection is complete, wait for the standard gas chamber pressure to stabilize and record the initial pressure P1 of the standard gas chamber;

[0030] 5) Open the inlet control valve and helium control valve of the core holder, and close the other control valves. The helium in the standard gas chamber enters the core sample set in the core holder. After the pressure in the standard gas chamber stabilizes, record the equilibrium pressure P2 of the standard gas chamber.

[0031] 6) Determine the porosity of the core sample based on its length and diameter, and the standard gas chamber pressures P1 and P2;

[0032] More preferably, the porosity of the core sample is determined by the following formula:

[0033]

[0034] Where V0 is the volume of the standard air chamber, in cm³. 3 P1 is the initial pressure of the standard gas chamber, in kPa; P2 is the equilibrium pressure of the standard gas chamber, in kPa; D is the diameter of the core sample, in cm; L is the length of the core sample, in cm. Porosity of the core sample, unit is dimensionless.

[0035] More preferably, in steps 2)-5), the difference between the confining pressure and the pressure at the fluid inlet of the core holder remains constant;

[0036] More preferably, the experimental control and data processing system is capable of executing saturated formation water procedures:

[0037] I. Start the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to subsequent steps II-III under the applied confining pressure conditions;

[0038] II. Open the venting control valve, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder.

[0039] III. After vacuuming is completed, open the core holder inlet control valve, core holder outlet control valve and formation water control valve, close the other control valves, and start the formation water supply assembly to saturate the core sample in the core holder with formation water.

[0040] More preferably, the experimental control and data processing system is capable of executing the carbon dioxide-water two-phase flow phase permeation curve test procedure:

[0041] A. Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to the subsequent step B under the applied confining pressure condition;

[0042] B. Open the core holder inlet control valve, core holder outlet control valve, saturated carbon dioxide formation water control valve and CO2 gas control valve, close the remaining control valves, start the back pressure system to apply back pressure to the core holder, start the saturated carbon dioxide formation water supply component and CO2 gas supply component to inject different types of fluids into the core sample at a constant rate, and obtain the pressure at the fluid inlet of the core holder and the pressure at the fluid outlet of the core holder, the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate after the injection pressure stabilizes during the injection process of each type of fluid. Then, dry the core sample with CO2.

[0043] Among them, different types of fluids refer to fluids composed of saturated carbon dioxide formation water and gaseous carbon dioxide with different flow ratios, and different types of fluids include pure saturated carbon dioxide formation water fluid and pure CO2 fluid; during the constant-rate injection of different types of fluids, the fluid with a high flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide is injected first, followed by the fluid with a low flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide, and the next type of fluid is injected only after the injection pressure of the first type of fluid has stabilized.

[0044] E. Based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilizes during the injection of various types of fluids, as well as the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the relative permeability of the water phase and the relative permeability of the gas phase in the core samples during the injection of various types of fluids are determined respectively. Based on the bound water saturation of the core samples and the saturated carbon dioxide formation water flow rate and gas phase carbon dioxide flow rate of various types of fluids, the water saturation during the injection of various types of fluids is determined respectively. Based on the relative permeability of the water phase and the relative permeability of the gas phase in the core samples during the injection of various types of fluids, combined with the water saturation during the injection of various types of fluids, the carbon dioxide-water two-phase permeability curve of the core samples is determined.

[0045] More preferably, based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilizes during the injection of various types of fluids, the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the relative permeability of the water phase and the relative permeability of the gas phase of the core sample during the injection of various types of fluids are determined, including:

[0046] Based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilizes during the injection of various types of fluids, as well as the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the effective water phase permeability and gas phase permeability of the core samples during the injection of various types of fluids are determined respectively.

[0047] Based on the effective water phase permeability and effective gas phase permeability of core samples when various types of fluids are injected, and taking the effective water phase permeability of core samples when injected with pure carbon dioxide formation water as the absolute permeability, the relative water phase permeability and relative gas phase permeability of core samples when various types of fluids are injected are determined respectively.

[0048] The effective permeability of the aqueous phase and the effective permeability of the gas phase in the core sample are determined by the following formula:

[0049]

[0050] In the formula, K gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q gi Let be the flow rate of gaseous carbon dioxide when the i-th type of fluid is injected, in cm. 3 ·s -1 μ g L is the viscosity of gaseous carbon dioxide, mPa·s; L is the core length, cm; A is the cross-sectional area of ​​the core perpendicular to the fluid flow direction, cm². 2 ΔP is the difference between the pressure at the fluid inlet of the core holder and the pressure at the fluid outlet of the core holder, 10 -1 MPa; K wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q wi Let be the flow rate of saturated carbon dioxide formation water during the injection of the i-th type of fluid, in cm. 3 ·s -1 μ w The viscosity of formation water saturated with carbon dioxide is mPa·s;

[0051] The absolute permeability of the water phase and the absolute permeability of the gas phase in the core sample are determined by the following formula:

[0052]

[0053]

[0054] In the formula, K rgi K represents the relative gas-phase permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K rwi K represents the liquid phase relative permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K w1 The effective water phase permeability of the core sample when injected with pure carbon dioxide-saturated formation water fluid, in μm. 2 ;

[0055] More preferably, based on the bound water saturation of the core sample and the saturated carbon dioxide formation water flow rate and gas phase carbon dioxide flow rate of various types of fluids, the water saturation at the time of injection of various types of fluids is determined, including:

[0056] Based on the bound water saturation, and combined with the flow ratio of saturated carbon dioxide formation water and gas phase carbon dioxide for various types of fluids, the water saturation at the time of injection of various types of fluids is determined by the following formulas; where the water saturation at the time of injection of pure saturated carbon dioxide formation water is 1.

[0057]

[0058] In the formula, S wi S represents the water saturation level when the i-th type of fluid is injected, which is dimensionless; wf7 Q represents the bound water saturation, which is dimensionless. i Let be the ratio of saturated carbon dioxide in formation water to gaseous carbon dioxide in the i-th type of fluid, dimensionless;

[0059] More preferably, the carbon dioxide-water two-phase flow phase permeation curve test procedure includes:

[0060] Based on the volume of bound water and pore volume in the core sample after CO2 drying, the bound water saturation of the core sample is determined using the following formula:

[0061]

[0062] In the formula, S wf7 V1 represents the bound water saturation, which is dimensionless; V2 represents the volume of bound water in the core sample after CO2 drying; V3 represents the volume of pores in the core sample after CO2 drying.

[0063] In one specific embodiment, the volume of bound water and the volume of pores in the CO2-dried core sample are determined by the following method:

[0064] Based on the data of the CO2-dried core samples obtained by the nuclear magnetic resonance testing system, the volume of bound water and the porosity of the CO2-dried core samples were determined.

[0065] More preferably, in steps B-D, the difference between the confining pressure and the pressure at the fluid inlet of the core holder remains constant;

[0066] More preferably, the experimental control and data processing system is capable of executing the aperture distribution test procedure:

[0067] Based on data obtained from the nuclear magnetic resonance testing system, the pore size distribution curve of the core sample was determined;

[0068] More preferably, the experimental control and data processing system is capable of executing a second porosity testing procedure:

[0069] Based on the porosity obtained by the first porosity test program, the pore size distribution curve of the core sample obtained for the first time by the pore size distribution test program (i.e., the pore size distribution curve of the core sample before CO2 dissolution of the core sample), and the pore size distribution curve of the core sample after CO2 dissolution for n hours obtained by the pore size distribution test program, the porosity of the core sample after CO2 dissolution for n hours is determined.

[0070] More preferably, the experimental control and data processing system is capable of executing CO2 dissolution procedures for core samples:

[0071] a. Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to the subsequent step b under the applied confining pressure condition;

[0072] b. Open the core holder inlet control valve, core holder outlet control valve and saturated carbon dioxide formation water control valve, close the other control valves, start the back pressure system to apply back pressure to the core holder, start the saturated carbon dioxide formation water supply component to inject saturated carbon dioxide formation water into the core sample for a period of time to CO2 dissolve the core sample.

[0073] More preferably, in step b, the difference between the confining pressure and the pressure at the fluid inlet of the core holder is constant;

[0074] More preferably, the experimental control and data processing system is capable of executing the CO2 dynamic dissolution test procedure:

[0075] (1) Perform the first porosity test procedure;

[0076] (2) Perform the saturated formation water procedure;

[0077] (3) Perform the pore size distribution test procedure and the carbon dioxide-water two-phase flow phase permeation curve test procedure;

[0078] (4) Perform the CO2 dissolution procedure on the core samples;

[0079] (5) Perform the pore size distribution test procedure, the carbon dioxide-water two-phase flow phase permeation curve test procedure, and the second porosity test procedure.

[0080] (6) Repeat steps (4) and (5) until the CO2 dissolution time of the core sample meets the target time.

[0081] The CO2 dynamic dissolution testing equipment provided by this invention consists of several key components that work together to achieve a comprehensive assessment of underground reservoir characteristics. Compared with existing technologies, the technical solution provided by this invention has the following advantages:

[0082] 1. The CO2 dynamic dissolution testing equipment provided by this invention takes into account nuclear magnetic resonance, ultra-low permeability gas phase permeation measurement and real-time data collection of core porosity, while also taking into account the limitations of X-ray CT scanning and other technologies in the application of tight oil. It can simply and accurately measure the changes in porosity, permeability and pore size distribution of CO2 dynamic dissolution in tight reservoirs, and realize the testing of the entire process in the same chamber.

[0083] 2. The CO2 dynamic dissolution testing equipment provided by this invention comprehensively considers the influence of changes in pore throat characteristics under the action of CO2 dynamic dissolution on the relative permeability of the supercritical CO2-water two-phase system, realizing integrated real-time monitoring and greatly reducing the loss of physical property testing of dissolution cores on different instruments.

[0084] 3. The CO2 dynamic dissolution testing equipment provided by this invention can maintain the same high temperature and high pressure, increase the injection CO2 flow rate, and collect real-time data on the pore size distribution of dissolved rock cores. Compared with previous technologies, it can accurately measure and continuously record the relative permeability of the CO2-water two-phase system during the dissolution process, reducing the influence of human error and uncertainties, and saving time.

[0085] 4. The CO2 dynamic dissolution testing equipment provided by this invention can meet the requirements of testing core properties under different temperatures and pressures, and realize the requirements of physical property detection within different temperature and pressure ranges. Compared with other single compact core testing instruments, it can obtain higher and more accurate precision and achieve a wider range of experimental conditions.

[0086] 5. The CO2 dynamic dissolution testing equipment provided by this invention can solve the problem of difficulty in simply and accurately measuring the dynamic dissolution characteristics of CO2 and the relative permeability of the CO2-water two-phase system during CO2 huff and puff in tight reservoirs due to the small matrix pore throats and poor multiphase flow capacity. Real-time monitoring of the changes in the pore size structure and two-phase flow rate of the core under continuous carbonic acid dissolution better reflects the two-phase flow law under the action of dynamic CO2 dissolution. Attached Figure Description

[0087] Figure 1 This is a schematic diagram of the CO2 dynamic dissolution testing equipment provided in Embodiment 1 of the present invention.

[0088] Figure 2 This is a graph showing the change in porosity of the dense core measured in Example 1 of the present invention. Detailed Implementation

[0089] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0090] Example 1

[0091] This embodiment provides a CO2 dynamic dissolution testing device, the structure of which is as follows: Figure 1 As shown.

[0092] The CO2 dynamic dissolution testing equipment includes a core holder 19 and a vacuum system. Figure 1 (Not shown), confining pressure system 22, back pressure system, fluid supply system, nuclear magnetic resonance testing system 17, sensor system, temperature control system, gas-liquid separator 23, fluid control system, experimental control and data processing system ( Figure 1 (Not shown).

[0093] The fluid supply system includes a CO2 gas supply component, a formation water supply component, a saturated carbon dioxide formation water supply component, and a helium supply component. The CO2 gas supply component includes a CO2 cylinder 3 and a booster pump 5, with the booster pump 5 located at the outlet of the CO2 cylinder 3. The formation water supply component includes a formation water storage container 7, a first ISCO pump 1, and a first pumping medium storage tank 2. The formation water storage container 7 is a piston-type intermediate container. The fluid outlet of the first pumping medium storage tank 2 is connected to the inlet of the first ISCO pump 1, and the outlet of the first ISCO pump 1 is connected to the bottom fluid port of the formation water storage container 7. The saturated carbon dioxide formation water supply component includes a saturated carbon dioxide formation water storage container 8, a second ISCO pump 24, and a second pumping medium storage tank 25. The fluid outlet of the second pumping medium storage tank 25 is connected to the inlet of the second ISCO pump 24, and the outlet of the second ISCO pump 24 is connected to the bottom fluid port of the saturated carbon dioxide formation water storage container 8. The helium supply assembly includes a helium cylinder 18 and a standard gas chamber 4. The gas outlet of the helium cylinder 18 is connected to the gas inlet of the standard gas chamber 4. The top fluid inlet of the formation water storage container 7, the top fluid inlet of the saturated carbon dioxide formation water storage container 8, the pump outlet of the booster pump 5, and the fluid outlet of the standard gas chamber 4 are connected in parallel to the main line connected to the fluid inlet of the core holder 19. This enables the top fluid inlet of the formation water storage container 7, the top fluid inlet of the saturated carbon dioxide formation water storage container 8, the pump outlet of the booster pump 5, and the fluid outlet of the standard gas chamber 4 to be connected to the fluid inlet of the core holder 19, respectively. The booster pump 5 is connected to the saturated carbon dioxide formation water storage container 8 (to provide CO2 gas to the saturated carbon dioxide formation water storage container 8 for the preparation of saturated carbon dioxide formation water), and the formation water storage container 7 is connected to the saturated carbon dioxide formation water storage container 8 (to provide formation water to the saturated carbon dioxide formation water storage container 8 for the preparation of saturated carbon dioxide formation water).

[0094] The nuclear magnetic resonance (NMR) testing system 17 is used to perform NMR testing on a core sample placed in the core holder 19. The NMR testing system 17 includes a nuclear magnetic resonance (NMR) probe located near the core sample, and includes a magnetic field and a transceiver antenna for exciting NMR signals and receiving feedback signals.

[0095] The sensor system includes a pressure sensor group, a temperature sensor 16, and a gas flow meter 12; the pressure sensor group includes a pressure sensor 9 for acquiring the pressure at the fluid inlet of the core holder 19 and a pressure sensor ( ) for acquiring the pressure at the fluid outlet of the core holder 19. Figure 1 (Not shown in the image) A pressure sensor used to obtain the pressure of the standard air chamber 4 (not shown in the image) Figure 1 (Not shown in the image) A pressure sensor used to obtain the confining pressure of the core holder 19 (not shown in the image) Figure 1(not shown in the image) and a pressure sensor for obtaining the back pressure of the core holder 19 (not shown in the image) Figure 1 (Not shown in the image); Temperature sensor 16 is used to obtain the temperature of the core sample set in core holder 19; Gas flow meter 12 is used to obtain the gas flow rate at the fluid inlet of core holder 19.

[0096] The confining pressure system 22 includes a confining pressure pump, which is connected to the confining pressure port of the core holder 19 to provide confining pressure for the core holder 19.

[0097] The back pressure system includes a back pressure valve 20 and a back pressure pump 21. The back pressure pump 21 is connected to the back pressure valve 20. The outlet of the back pressure valve 20 is connected to the fluid outlet of the core holder 19 to provide back pressure to the core holder 19.

[0098] The vacuum system is connected to the vent of the core holder 19 to achieve vacuuming of the core sample set in the core holder 19.

[0099] The temperature control system is used to provide a suitable temperature for the core holder 19.

[0100] The gas-liquid separator 23 is connected to the fluid outlet of the core holder 19 to separate the fluid and liquid extracted by the core holder 19 so as to collect and analyze data in the experiment.

[0101] A dryer 13 is installed at the fluid inlet of the core holder 19.

[0102] The fluid control system includes a CO2 gas control valve 6, located on the connecting pipeline between the CO2 cylinder 3 and the fluid inlet of the core holder 19, for controlling the flow rate of CO2 gas injected into the core holder 19; a formation water control valve 15, located on the connecting pipeline between the formation water storage container 7 and the fluid inlet of the core holder 19, for controlling the flow rate of formation water injected into the core holder 19; and a saturated carbon dioxide formation water storage container 8, located on the connecting pipeline between the fluid inlet of the core holder 19, for controlling the flow rate of CO2 gas injected into the core holder 19. The system includes: a saturated carbon dioxide formation water control valve 26 for controlling the flow rate of saturated carbon dioxide formation water; a helium control valve (including a pressure regulating valve 10 and a gas supply valve 11) installed on the connecting pipeline between the standard gas chamber 4 and the fluid inlet of the core holder 19 to control the flow rate of helium injected into the core holder 19; a core holder inlet control valve 27 installed at the fluid inlet of the core holder 19; a core holder outlet control valve 28 installed at the fluid outlet of the core holder 19; and a vent control valve 14 installed at the vent port of the core holder 19.

[0103] The experimental control and data processing system is connected to the power unit and control valves in the CO2 dynamic dissolution testing equipment. It regulates the operation of the power unit and control valves according to a set program to complete the CO2 dynamic dissolution test and determine the porosity, carbon dioxide-water two-phase flow phase permeability curve, and pore size distribution of the core sample during the CO2 dynamic dissolution process. The experimental control and data processing system is capable of executing the CO2 dynamic dissolution test procedure.

[0104] (1) Perform the first porosity test procedure;

[0105] (2) Perform the saturated formation water procedure;

[0106] (3) Perform the pore size distribution test procedure and the carbon dioxide-water two-phase flow phase permeation curve test procedure;

[0107] (4) Perform the CO2 dissolution procedure on the core samples;

[0108] (5) Perform the pore size distribution test procedure, the carbon dioxide-water two-phase flow phase permeation curve test procedure, and the second porosity test procedure.

[0109] (6) Repeat steps (4) and (5) until the CO2 dissolution time of the core sample meets the target time.

[0110] The first porosity test procedure is as follows:

[0111] 1) Activate the confining pressure system 22 to apply confining pressure to the core sample set in the core holder 19, and proceed with subsequent steps 2)-5) under the applied confining pressure conditions;

[0112] 2) Open the venting control valve 14, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder 29;

[0113] 3) After the vacuuming is completed, open the helium control valve, close the other control valves, and start the helium cylinder 18 to inject a certain amount of helium into the standard gas chamber 4.

[0114] 4) After helium injection is complete, wait for the pressure in standard gas chamber 4 to stabilize and record the pressure P1 in standard gas chamber 4.

[0115] 5) Open the inlet control valve 27 and the helium control valve of the core holder, and close the other control valves. The helium in the standard gas chamber 4 enters the core sample set in the core holder 19. After the pressure in the standard gas chamber 4 stabilizes, record the pressure P2 of the standard gas chamber.

[0116] 6) Determine the porosity of the core sample based on its length and diameter, and the pressures P1 and P2 in the standard gas chamber 4;

[0117] In steps 2) to 5), the difference between the confining pressure and the pressure at the fluid inlet of the core holder 19 remains constant.

[0118] Saturated formation water process:

[0119] I. Start the confining pressure system 22 to apply confining pressure to the core sample set in the core holder 19, and proceed to subsequent steps II-III under the applied confining pressure conditions;

[0120] II. Open the venting control valve 14, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder 19.

[0121] III. After vacuuming is completed, open the core holder inlet control valve 27, the core holder outlet control valve 28 and the formation water control valve 15, close the remaining control valves, and start the formation water supply assembly to saturate the core sample set in the core holder 19 with formation water.

[0122] The procedure for testing the relative permeability curve of carbon dioxide-water two-phase flow is as follows:

[0123] A. Start the confining pressure system 22 to apply confining pressure to the core sample set in the core holder 19, and proceed to the subsequent step B under the confining pressure condition;

[0124] B. Open the core holder inlet control valve 27, core holder outlet control valve 28, saturated carbon dioxide formation water control valve 26 and CO2 gas control valve 6, close the remaining control valves, start the back pressure system to apply back pressure to the core holder 19, start the saturated carbon dioxide formation water supply component and CO2 gas supply component to inject different types of fluids into the core sample at a constant rate, and obtain the pressure at the fluid inlet of the core holder 19 and the pressure at the fluid outlet of the core holder 19, the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate after the injection pressure stabilizes during the injection process of each type of fluid. Then dry the core sample with CO2.

[0125] Among them, different types of fluids refer to fluids composed of saturated carbon dioxide formation water and gaseous carbon dioxide with different flow ratios, and different types of fluids include pure saturated carbon dioxide formation water fluid and pure CO2 fluid; during the constant-rate injection of different types of fluids, the fluid with a high flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide is injected first, followed by the fluid with a low flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide, and the next type of fluid is injected only after the injection pressure of the first type of fluid has stabilized.

[0126] E. Based on the pressure at the fluid inlet and outlet of the core holder 19 after the injection pressure stabilizes during the injection of various types of fluids, the gas phase carbon dioxide flow rate, and the saturated carbon dioxide formation water flow rate, the effective permeability of the aqueous phase and the effective permeability of the gas phase of the core samples during the injection of various types of fluids are determined respectively. Based on the effective permeability of the aqueous phase and the effective permeability of the gas phase of the core samples during the injection of various types of fluids, and taking the effective permeability of the aqueous phase of the core samples when injecting pure saturated carbon dioxide formation water as the absolute permeability, the relative permeability of the aqueous phase and the relative permeability of the gas phase of the core samples during the injection of various types of fluids are determined respectively.

[0127] Based on the bound water saturation, and combined with the flow ratio of saturated carbon dioxide formation water and gas phase carbon dioxide for various types of fluids, the water saturation at the time of injection of various types of fluids is determined by the following formulas; where the water saturation at the time of injection of pure saturated carbon dioxide formation water is 1.

[0128] Based on the relative permeability of water and gas phases of core samples during the injection of various types of fluids, and combined with the water saturation during the injection of various types of fluids, the carbon dioxide-water two-phase flow phase permeability curves of core samples were determined.

[0129] The effective permeability of the aqueous phase and the effective permeability of the gas phase in the core sample are determined by the following formula:

[0130]

[0131] In the formula, K gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q gi Let be the flow rate of gaseous carbon dioxide when the i-th type of fluid is injected, in cm. 3 ·s -1 μ g L is the viscosity of gaseous carbon dioxide, mPa·s; L is the core length, cm; A is the cross-sectional area of ​​the core perpendicular to the fluid flow direction, cm². 2 ΔP is the difference between the pressure at the fluid inlet of the core holder and the pressure at the fluid outlet of the core holder, 10 -1 MPa; K wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q wi Let be the flow rate of saturated carbon dioxide formation water during the injection of the i-th type of fluid, in cm. 3 ·s -1 μ w The viscosity of formation water saturated with carbon dioxide is mPa·s;

[0132] The absolute permeability of the water phase and the absolute permeability of the gas phase in the core sample are determined by the following formula:

[0133]

[0134]

[0135] In the formula, K rgi K represents the relative gas-phase permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K rwi K represents the liquid phase relative permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K w1 The effective water phase permeability of the core sample when injected with pure carbon dioxide-saturated formation water fluid, in μm. 2 ;

[0136] The water saturation level during the injection of various types of fluids is determined by the following formula:

[0137]

[0138] In the formula, S wi S represents the water saturation level when the i-th type of fluid is injected, which is dimensionless; wf7 Q represents the bound water saturation, which is dimensionless. i Let be the ratio of saturated carbon dioxide in formation water to gaseous carbon dioxide in the i-th type of fluid, dimensionless;

[0139] The bound water saturation of the core sample is determined by the following formula:

[0140]

[0141] In the formula, S wf7 V1 represents the bound water saturation, which is dimensionless; V2 represents the volume of bound water in the CO2-dried core sample; V3 represents the volume of pores in the CO2-dried core sample. The volumes of bound water (V1) and pores (V2) in the CO2-dried core sample were determined based on data from the CO2-dried core sample obtained by the nuclear magnetic resonance testing system.

[0142] In steps B-D, the difference between the confining pressure and the pressure at the fluid inlet of the core holder 19 remains constant.

[0143] The pore size distribution test procedure is as follows:

[0144] Based on data obtained from the nuclear magnetic resonance testing system, the pore size distribution curve of the core sample was determined.

[0145] The second porosity test procedure is as follows:

[0146] Based on the porosity determined by the first porosity test program, the pore size distribution curve of the core sample obtained for the first time by the pore size distribution test program (i.e., the pore size distribution curve of the core sample before CO2 dissolution of the core sample), and the pore size distribution curve of the core sample after CO2 dissolution for n hours obtained by the pore size distribution test program, the porosity of the core sample after CO2 dissolution for n hours is determined.

[0147] The procedure for CO2 dissolution of core samples is as follows:

[0148] a. Start the confining pressure system 22 to apply confining pressure to the core sample set in the core holder 19, and proceed to the subsequent step b under the confining pressure condition;

[0149] b. Open the core holder inlet control valve 27, the core holder outlet control valve 28 and the saturated carbon dioxide formation water control valve 26, close the remaining control valves, start the back pressure system to apply back pressure to the core holder 19, start the saturated carbon dioxide formation water supply component to inject saturated carbon dioxide formation water into the core sample for a period of time to CO2 dissolve the core sample.

[0150] In step b, the difference between the confining pressure and the pressure at the fluid inlet of the core holder 19 is constant.

[0151] The CO2 dynamic dissolution test conducted using the CO2 dynamic dissolution testing equipment provided by the present invention is as follows: The dried core sample is placed in the core holder 19, the CO2 dynamic dissolution testing equipment is connected, and the experimental control and data processing system is started to execute the CO2 dynamic dissolution testing procedure to perform the CO2 dynamic dissolution test on the core sample. Specifically, in the CO2 dissolution core sample procedure, the saturated carbon dioxide formation water supply component is activated to inject saturated carbon dioxide formation water into the core sample for 2 hours to perform CO2 dissolution of the core sample. The CO2 dissolution time of the core sample finally reaches the target duration of 72 hours, and the CO2 dynamic dissolution test procedure ends. The porosity test results are as follows: Figure 2 As shown.

[0152] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A CO2 dynamic dissolution testing device, wherein, The equipment includes: core holder, vacuum system, confining pressure system, back pressure system, fluid supply system, nuclear magnetic resonance testing system, sensor system, and temperature control system; The fluid supply system includes a CO2 gas supply component, a formation water supply component, a saturated carbon dioxide formation water supply component, and a helium supply component. The helium supply component includes a helium cylinder and a standard gas chamber. The gas outlet of the helium cylinder is connected to the gas inlet of the standard gas chamber. The CO2 gas supply component, the formation water supply component, the saturated carbon dioxide formation water supply component, and the standard gas chamber are respectively connected to the fluid inlet of the core holder. The nuclear magnetic resonance (NMR) testing system is used to perform NMR testing on core samples placed in a core holder. The sensor system includes a pressure sensor group, which includes a pressure sensor for acquiring the pressure at the fluid inlet of the core holder, a pressure sensor for acquiring the pressure at the fluid outlet of the core holder, and a pressure sensor for acquiring the pressure of the standard gas chamber. The confining pressure system is connected to the confining pressure port of the core holder. The back pressure system is connected to the fluid outlet of the core holder. The vacuum system is connected to the vent port of the core holder. The temperature control system is used to provide a suitable temperature for the core holder.

2. The device according to claim 1, wherein, The CO2 gas supply assembly includes a CO2 gas cylinder, the formation water supply assembly includes a formation water storage container, and the saturated carbon dioxide formation water supply assembly includes a saturated carbon dioxide formation water storage container. Preferably, the formation water storage container is a piston-type intermediate container, and the saturated carbon dioxide formation water storage container is a piston-type intermediate container; the formation water supply assembly also includes a first ISCO pump and a first pumping medium storage tank, the saturated carbon dioxide formation water supply assembly also includes a second ISCO pump and a second pumping medium storage tank, and the CO2 gas supply assembly also includes a booster pump; the fluid outlet of the first pumping medium storage tank is connected to the inlet of the first ISCO pump, the outlet of the first ISCO pump is connected to the bottom fluid port of the formation water storage container, the fluid outlet of the second pumping medium storage tank is connected to the inlet of the second ISCO pump, the outlet of the second ISCO pump is connected to the bottom fluid port of the saturated carbon dioxide formation water storage container, the booster pump is located at the outlet of the CO2 gas cylinder, the top fluid port of the formation water storage container is connected to the fluid inlet of the core holder, and the top fluid port of the saturated carbon dioxide formation water storage container is connected to the fluid inlet of the core holder.

3. The device according to claim 2, wherein, The CO2 cylinder is also connected to a saturated carbon dioxide formation water storage container to supply CO2 gas to the saturated carbon dioxide formation water storage container for the preparation of saturated carbon dioxide formation water. The formation water storage container is also connected to a saturated carbon dioxide formation water storage container to supply formation water to the saturated carbon dioxide formation water storage container for the preparation of saturated carbon dioxide formation water.

4. The device according to claim 1, wherein, The sensor system also includes a temperature sensor to acquire the temperature of the core sample placed in the core holder; The pressure sensor group also includes a pressure sensor for acquiring the confining pressure of the core holder and a pressure sensor for acquiring the back pressure of the core holder.

5. The device according to claim 1, wherein, The CO2 dynamic dissolution testing equipment also includes a fluid control system, which includes a CO2 gas control valve installed on the connecting pipeline between the CO2 gas cylinder and the fluid inlet of the core holder to control the flow rate of CO2 gas injected into the core holder; a formation water control valve installed on the connecting pipeline between the formation water storage container and the fluid inlet of the core holder to control the flow rate of formation water injected into the core holder; a saturated carbon dioxide formation water control valve installed on the connecting pipeline between the saturated carbon dioxide formation water storage container and the fluid inlet of the core holder to control the flow rate of saturated carbon dioxide formation water injected into the core holder; a helium control valve installed on the connecting pipeline between the standard gas chamber and the fluid inlet of the core holder to control the flow rate of helium gas injected into the core holder; a core holder inlet control valve installed at the fluid inlet of the core holder; a core holder outlet control valve installed at the fluid outlet of the core holder; and a vent control valve installed at the vent port of the core holder.

6. The device according to claim 5, wherein, The CO2 dynamic dissolution testing equipment also includes an experimental control and data processing system. The experimental control and data processing system is connected to the power unit and various control valves in the CO2 dynamic dissolution testing equipment to regulate the operation of the power unit and various control valves according to the set program, complete the CO2 dynamic dissolution testing experiment, and determine the porosity, carbon dioxide-water two-phase flow phase permeation curve, and pore size distribution of the core sample during the CO2 dynamic dissolution process.

7. The device according to claim 6, wherein, The experimental control and data processing system is capable of executing the first porosity test procedure: 1) Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to subsequent steps 2)-5) under the applied confining pressure conditions; 2) Open the venting control valve, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder; 3) After the vacuuming is completed, open the helium control valve, close the other control valves, and start the helium cylinder to inject a certain amount of helium into the standard gas chamber; 4) After helium injection is complete, wait for the standard gas chamber pressure to stabilize and record the standard gas chamber pressure P1; 5) Open the inlet control valve and helium control valve of the core holder, and close the other control valves. The helium in the standard gas chamber enters the core sample set in the core holder. After the pressure in the standard gas chamber stabilizes, record the pressure P2 of the standard gas chamber. 6) Determine the porosity of the core sample based on its length and diameter, and the standard gas chamber pressures P1 and P2; Preferably, in steps 2)-5), the difference between the confining pressure and the pressure at the fluid inlet of the core holder remains constant.

8. The device according to claim 7, wherein, The experimental control and data processing system is capable of executing saturated formation water procedures: I. Start the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to subsequent steps II-III under the applied confining pressure conditions; II. Open the venting control valve, close the other control valves, and start the vacuum system to evacuate the core sample set in the core holder. III. After vacuuming is completed, open the core holder inlet control valve, the core holder outlet control valve, and the formation water control valve, close the remaining control valves, and start the formation water supply assembly to saturate the core sample in the core holder with formation water.

9. The device according to claim 8, wherein, The experimental control and data processing system is capable of executing the carbon dioxide-water two-phase flow phase permeation curve test procedure: A. Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to the subsequent step B under the applied confining pressure condition; B. Open the core holder inlet control valve, core holder outlet control valve, saturated carbon dioxide formation water control valve and CO2 gas control valve, close the remaining control valves, start the back pressure system to apply back pressure to the core holder, start the saturated carbon dioxide formation water supply component and CO2 gas supply component to inject different types of fluids into the core sample at a constant rate, and obtain the pressure at the fluid inlet of the core holder and the pressure at the fluid outlet of the core holder, the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate after the injection pressure stabilizes during the injection process of each type of fluid. Then, dry the core sample with CO2. Among them, different types of fluids refer to fluids composed of saturated carbon dioxide formation water and gaseous carbon dioxide with different flow ratios, and different types of fluids include pure saturated carbon dioxide formation water fluid and pure CO2 fluid; during the constant-rate injection of different types of fluids, the fluid with a high flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide is injected first, followed by the fluid with a low flow ratio of saturated carbon dioxide formation water and gaseous carbon dioxide, and the next type of fluid is injected only after the injection pressure of the first type of fluid has stabilized. E. Based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilizes during the injection of various types of fluids, as well as the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the relative permeability of the water phase and the relative permeability of the gas phase in the core samples during the injection of various types of fluids are determined respectively. Based on the bound water saturation of the core samples and the saturated carbon dioxide formation water flow rate and gas phase carbon dioxide flow rate of various types of fluids, the water saturation during the injection of various types of fluids is determined respectively. Based on the relative permeability of the water phase and the relative permeability of the gas phase in the core samples during the injection of various types of fluids, combined with the water saturation during the injection of various types of fluids, the carbon dioxide-water two-phase permeability curve of the core samples is determined. Preferably, in steps B-D, the difference between the confining pressure and the pressure at the fluid inlet of the core holder remains constant.

10. The device according to claim 9, wherein, Based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilized during the injection of various types of fluids, as well as the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the relative permeability of the water phase and the relative permeability of the gas phase in the core samples during the injection of various types of fluids were determined, including: Based on the pressure at the fluid inlet and outlet of the core holder after the injection pressure stabilizes during the injection of various types of fluids, as well as the gas phase carbon dioxide flow rate and the saturated carbon dioxide formation water flow rate, the effective water phase permeability and gas phase permeability of the core samples during the injection of various types of fluids are determined respectively. Based on the effective water phase permeability and effective gas phase permeability of core samples when various types of fluids are injected, and taking the effective water phase permeability of core samples when injected with pure carbon dioxide formation water as the absolute permeability, the relative water phase permeability and relative gas phase permeability of core samples when various types of fluids are injected are determined respectively. The effective permeability of the aqueous phase and the effective permeability of the gas phase in the core sample are determined by the following formula: In the formula, K gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q gi Let be the flow rate of gaseous carbon dioxide when the i-th type of fluid is injected, in cm. 3 ·s -1 μ g L is the viscosity of gaseous carbon dioxide, mPa·s; L is the core length, cm; A is the cross-sectional area of ​​the core perpendicular to the fluid flow direction, cm². 2 ΔP is the difference between the pressure at the fluid inlet of the core holder and the pressure at the fluid outlet of the core holder, 10 -1 MPa; K wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 Q wi Let be the flow rate of saturated carbon dioxide formation water during the injection of the i-th type of fluid, in cm. 3 ·s -1 μ w The viscosity of formation water saturated with carbon dioxide is mPa·s; The absolute permeability of the water phase and the absolute permeability of the gas phase in the core sample are determined by the following formula: In the formula, K rgi K represents the relative gas-phase permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. gi Let be the effective gas-phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K rwi K represents the liquid phase relative permeability of the core sample when the i-th type of fluid is injected; it is dimensionless. wi Let be the effective liquid phase permeability of the core sample when the i-th type of fluid is injected, in μm. 2 ;K w1 The effective water phase permeability of the core sample when injected with pure carbon dioxide-saturated formation water fluid, in μm. 2 .

11. The device according to claim 9, wherein, Based on the bound water saturation of core samples and the saturated carbon dioxide formation water flow rate and gas phase carbon dioxide flow rate of various types of fluids, the water saturation at the time of injection of various types of fluids was determined, including: Based on the bound water saturation, and combined with the flow ratio of saturated carbon dioxide formation water and gas phase carbon dioxide for various types of fluids, the water saturation at the time of injection of various types of fluids is determined by the following formulas; where the water saturation at the time of injection of pure saturated carbon dioxide formation water is 1. In the formula, S wi S represents the water saturation level when the i-th type of fluid is injected, which is dimensionless; wf7 Q represents the bound water saturation, which is dimensionless. i Let be the ratio of saturated carbon dioxide in formation water to gaseous carbon dioxide in the i-th type of fluid, dimensionless.

12. The device according to claim 9, wherein, The procedure for testing the relative permeability curve of carbon dioxide-water two-phase flow includes: Based on the volume of bound water and pore volume in the core sample after CO2 drying, the bound water saturation of the core sample is determined using the following formula: In the formula, S wf7 V1 represents the bound water saturation, which is dimensionless; V2 represents the volume of bound water in the core sample after CO2 drying; V3 represents the volume of pores in the core sample after CO2 drying. The volume of bound water and the volume of pores in the CO2-dried core sample were determined as follows: Based on data from CO2-dried core samples obtained using a nuclear magnetic resonance (NMR) testing system, the volume of bound water and porosity in the CO2-dried core samples were determined.

13. The device according to claim 9, wherein, The experimental control and data processing system is capable of executing aperture distribution test procedures: Based on data obtained from the nuclear magnetic resonance testing system, the pore size distribution curve of the core sample was determined.

14. The device according to claim 13, wherein, The experimental control and data processing system is capable of executing CO2 dissolution procedures for core samples: a. Activate the confining pressure system to apply confining pressure to the core sample placed in the core holder, and proceed to the subsequent step b under the applied confining pressure condition; b. Open the core holder inlet control valve, core holder outlet control valve and saturated carbon dioxide formation water control valve, close the other control valves, start the back pressure system to apply back pressure to the core holder, start the saturated carbon dioxide formation water supply component to inject saturated carbon dioxide formation water into the core sample for a period of time to CO2 dissolve the core sample. Preferably, in step b, the difference between the confining pressure and the pressure at the fluid inlet of the core holder is constant.

15. The device according to claim 14, wherein, The experimental control and data processing system is capable of executing the second porosity test procedure: Based on the porosity determined by the first porosity test program, the pore size distribution curve of the core sample obtained for the first time by the pore size distribution test program (i.e., the pore size distribution curve of the core sample before CO2 dissolution of the core sample), and the pore size distribution curve of the core sample after CO2 dissolution for n hours obtained by the pore size distribution test program, the porosity of the core sample after CO2 dissolution for n hours is determined.

16. The device according to claim 15, wherein, The experimental control and data processing system is capable of executing the CO2 dynamic dissolution test procedure: (1) Perform the first porosity test procedure; (2) Perform the saturated formation water procedure; (3) Perform the pore size distribution test procedure and the carbon dioxide-water two-phase flow phase permeation curve test procedure; (4) Perform the CO2 dissolution procedure on the core samples; (5) Perform the pore size distribution test procedure, the carbon dioxide-water two-phase flow phase permeation curve test procedure, and the second porosity test procedure. (6) Repeat steps (4) and (5) until the CO2 dissolution time of the core sample meets the target time.

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