Device and method for measuring critical speed of carbon dioxide foam generation and propagation

Abstract

The present application discloses a critical speed measuring device for the generation and propagation of carbon dioxide foam, which relates to the field of oil and natural gas exploitation. The critical speed measuring device includes a carbon dioxide gas cylinder, a surfactant solution device, an air mass flow meter, a displacement pump, a core clamp, a pressure sensor and a data acquisition device; the data acquisition device acquires in real time the first injection speed of carbon dioxide injected into the core clamp, the second injection speed of the surfactant solution injected into the core clamp, and the inlet pressure and outlet pressure of the core in the core clamp; the critical speed of generation and propagation of carbon dioxide foam in the core are determined according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure. By determining the critical speed of generation and propagation of carbon dioxide foam, a theoretical basis can be provided for the development of oil and gas reservoir foam injection, and then the optimal injection amount of carbon dioxide foam can be determined to maximize production benefits.

Description

Technical Field

[0001] The present application relates to the field of oil and gas exploitation, and in particular to a critical velocity measurement device and method for carbon dioxide foam generation and propagation. Background Art

[0002] Carbon dioxide flooding is one of the important methods to improve the recovery rate of oil and gas reservoirs. The injected carbon dioxide mainly improves the flow characteristics of formation crude oil in the form of miscible or immiscible phases. However, the actual reservoirs are often highly heterogeneous. At the same time, due to the gravity effect and fluid mobility differences, the displacement efficiency in the later stage of gas injection development is low, resulting in a large amount of residual oil that cannot be recovered. The injection of foam can greatly reduce the flow capacity of the gas, effectively improve the displacement profile, and expand the swept volume of the gas. The surfactant in the foam system can also reduce the oil-water interfacial tension to a certain extent and improve the oil washing efficiency.

[0003] At present, carbon dioxide foam flooding has been widely used in field experiments. Carbon dioxide foam is usually injected at a high rate during oil production, which has poor economic benefits, and the high injection rate of carbon dioxide foam has high requirements for equipment. The generation and propagation of foam in porous media requires maintaining a minimum pressure drop, and the shear effect during movement triggers the generation of more bubbles. The process of stable seepage of foam mainly depends on the minimum pressure gradient (minimum apparent velocity) and the physical properties of rock fluids (such as permeability, surface tension and volume fraction of injected liquid). There is no relevant research report analyzing how to determine the critical velocity of carbon dioxide foam generation and propagation in the formation.

[0004] Therefore, how to measure the critical speed of carbon dioxide foam generation and propagation is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The purpose of the present application is to provide a device and method for measuring the critical speed of carbon dioxide foam generation and propagation, which are used to measure the critical speed of carbon dioxide foam generation and propagation.

[0006] In order to solve the above technical problems, the present application provides a critical velocity measurement device for carbon dioxide foam generation and propagation, comprising a carbon dioxide gas cylinder, a surfactant solution device, an air mass flow meter, a displacement pump, a core holder, a pressure sensor and a data acquisition device;

[0007] The carbon dioxide gas cylinder is connected to the inlet end of the core holder through a first pipeline, and the first pipeline is provided with the air mass flow meter, and the air mass flow meter is used to adjust a first injection speed of carbon dioxide injected into the core holder;

[0008] The surfactant solution device is connected to the inlet end of the core holder through a second pipeline, and the second pipeline is provided with the displacement pump, and the displacement pump is used to adjust a second injection speed of the surfactant solution injected into the core holder;

[0009] A core is arranged inside the core holder, and the pressure sensors are respectively arranged at both ends of the core, and the pressure sensors are used to monitor the inlet pressure and the outlet pressure of the core in real time when the carbon dioxide and the surfactant solution are injected into the core holder at the same time;

[0010] The air mass flow meter, the displacement pump and the pressure sensor are respectively connected to the data acquisition device, and the data acquisition device is used to obtain in real time the first injection rate, the second injection rate, and the inlet pressure and the outlet pressure corresponding to the first injection rate and the second injection rate, so as to determine the critical speed of generation and propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure and the outlet pressure.

[0011] Preferably, the core holder comprises a plurality of sub-core holders of different diameters, and along the inlet end to the outlet end of the core holder, the diameter of the latter sub-core holder is greater than the diameter of the former sub-core holder;

[0012] Correspondingly, the core disposed inside the core holder includes a plurality of sub-cores with different diameters, and the pressure sensors are respectively disposed at both ends of each sub-core.

[0013] Preferably, it further comprises a constant temperature box and a temperature sensor, wherein the core holder is placed in the constant temperature box, the temperature sensor is connected to the data acquisition device, and the temperature sensor is used to detect the temperature in the constant temperature box.

[0014] Preferably, a back pressure controller is further included, and the back pressure controller is arranged at the outlet end of the core holder, and the back pressure controller is used to ensure that the pressure at the outlet end is constant.

[0015] Preferably, it further comprises a fluid extraction device, wherein the fluid extraction device is used to collect liquid flowing out from the outlet end of the core holder.

[0016] The present application also provides a critical speed measurement method for carbon dioxide foam generation and propagation, which is applied to the critical speed measurement device for carbon dioxide foam generation and propagation, and comprises:

[0017] Real-time acquisition of a first injection rate of carbon dioxide into a core holder, a second injection rate of a surfactant solution into the core holder, and an inlet pressure and an outlet pressure of a core in the core holder corresponding to the first injection rate and the second injection rate;

[0018] The critical speed of generation and the critical speed of propagation of carbon dioxide foam in the core are determined according to the first injection speed, the second injection speed, the pressure at the inlet and the pressure at the outlet.

[0019] Preferably, determining the critical speed of carbon dioxide foam generation in the core according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure comprises:

[0020] Calculating the superficial flow rate of carbon dioxide foam in the core according to the first injection rate, the second injection rate and the diameter of the core;

[0021] Calculate the pressure difference according to the inlet pressure and the outlet pressure;

[0022] The pressure difference change rate is determined according to the current pressure difference and the historical pressure difference. When the pressure difference change rate reaches a preset value, the target apparent flow rate corresponding to the current pressure difference is determined, and the target apparent flow rate is used as the critical speed for generating the carbon dioxide foam.

[0023] Preferably, determining the critical speed of generation and critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure and the outlet pressure includes:

[0024] Calculating the superficial flow rate of carbon dioxide in the core according to the first injection rate, the second injection rate and the diameter of the core;

[0025] Calculating a pressure difference according to the inlet pressure and the outlet pressure, and determining a pressure gradient according to the pressure difference and the diameter of the core;

[0026] Obtaining a corresponding relationship diagram between a control apparent flow velocity and a control pressure gradient;

[0027] Determining whether the apparent flow velocity and the pressure gradient corresponding to the apparent flow velocity conform to the corresponding relationship diagram;

[0028] If so, the critical generation speed and the critical propagation speed of the carbon dioxide foam are determined according to the corresponding relationship diagram.

[0029] Preferably, after determining the critical speed of generation and critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure and the outlet pressure, the method further comprises:

[0030] The critical bursting speed of the carbon dioxide foam is determined according to the corresponding relationship diagram.

[0031] The present application provides a critical speed measuring device for the generation and propagation of carbon dioxide foam, including a carbon dioxide gas cylinder, a surfactant solution device, an air mass flow meter, a displacement pump, a core clamp, a pressure sensor and a data acquisition device; the data acquisition device acquires in real time the first injection speed of carbon dioxide injected into the core clamp, the second injection speed of the surfactant solution injected into the core clamp, and the inlet pressure and outlet pressure of the core in the core clamp corresponding to the first injection speed and the second injection speed; the critical speed of generation and propagation of carbon dioxide foam in the core are determined according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure. By determining the critical speed of generation and propagation of carbon dioxide foam, a theoretical basis can be provided for the development of oil and gas reservoir foam injection, and then the optimal injection amount of carbon dioxide foam can be determined to maximize production benefits.

[0032] The present application provides a method and device for measuring the critical speed of carbon dioxide foam generation and propagation, and the effects are as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A structural diagram of a critical speed measurement device for carbon dioxide foam generation and propagation provided in an embodiment of the present application;

[0035] Figure 2 A structural diagram of a variable diameter core holder provided in an embodiment of the present application;

[0036] Figure 3 A flow chart of a critical speed measurement method for carbon dioxide foam generation and propagation provided in an embodiment of the present application;

[0037] Figure 4 A graph showing changes in pressure difference over time provided in an embodiment of the present application;

[0038] Figure 5A correspondence diagram between apparent flow velocity and pressure gradient provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] The core of this application is to provide a critical speed measurement device and method for the generation and propagation of carbon dioxide foam.

[0041] At present, the two most widely used foam models are the population conservation model and the implicit foam model. The population conservation model introduces pressure gradient to describe the dynamic generation process of foam, while the implicit foam model indirectly expresses the effect of pressure gradient on foam generation through capillary bundles. Both foam models can accurately predict the propagation distance of nitrogen foam in the formation. However, for different formations, the difference in permeability will lead to different minimum pressure gradients required for foam propagation, which in turn affects the propagation distance of foam in the formation. At the same time, the type of gas used will also affect the generation and propagation of foam.

[0042] Therefore, the present application proposes a device and method for measuring the critical velocity of carbon dioxide foam generation and propagation in porous media, which can more accurately measure the critical velocity required for carbon dioxide foam generation and propagation in formations.

[0043] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0044] Figure 1 A structural diagram of a critical speed measurement device for carbon dioxide foam generation and propagation provided in an embodiment of the present application, such as Figure 1As shown, the critical velocity measuring device includes: 1 is a carbon dioxide gas cylinder, 2 is a surfactant solution device, 3 is an air mass flow meter, 4 is a displacement pump, 5 is a core holder, 6 is a pressure sensor, 7 is a data acquisition device, 8 is a constant temperature box, 9 is a temperature sensor, 10 is a back pressure controller and 11 is a fluid production device. The carbon dioxide cylinder 1 is connected to the inlet end of the core holder 5 through a first pipeline, and the first pipeline is provided with an air mass flowmeter 3, and the air mass flowmeter 3 is used to adjust the first injection speed of carbon dioxide injected into the core holder 5; the surfactant solution device 2 is connected to the inlet end of the core holder 5 through a second pipeline, and the second pipeline is provided with a displacement pump 4, and the displacement pump 4 is used to adjust the second injection speed of the surfactant solution injected into the core holder 5; a core is arranged inside the core holder 5, and pressure sensors 6 are respectively arranged at both ends of the core, and the pressure sensor 6 is used to monitor the inlet pressure and outlet pressure of the core in real time when carbon dioxide and surfactant solution are injected into the core holder 5 at the same time; the air mass flowmeter 3, the displacement pump 4 and the pressure sensor 6 are respectively connected to the data acquisition device 7, and the data acquisition device 7 is used to monitor the first injection speed, the second injection speed, and the inlet pressure and outlet pressure corresponding to the first injection speed and the second injection speed in real time, so as to determine the critical speed of generation and propagation of carbon dioxide foam in the core according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure.

[0045] The embodiment of the present application does not specifically limit the core clamp 5. In order to better simulate the formation, it can be a variable diameter metal core clamp, that is, the core clamp 5 includes multiple sections of sub-core clamps with different diameters. Along the inlet end to the outlet end of the core clamp 5, the diameter of the latter section of the sub-core clamp is larger than the diameter of the former section of the sub-core clamp. Figure 2 A structural diagram of a variable diameter core holder is provided for an embodiment of the present application, such as Figure 2As shown, the total length is 40.0cm, and it is divided into 3 sections along the way. Section A is 6.0cm long and has an inner diameter of 1.5cm; Section B is 8.0cm long and has an inner diameter of 3.0cm; Section C is 26.0cm long and has an inner diameter of 4.5cm. Correspondingly, the core provided inside the core holder 5 includes multiple sections of sub-cores with different diameters, and pressure sensors 6 are provided at both ends of each section of the sub-core; of course, one or more pressure sensors 6 can be provided between the two ends of each section of the sub-core; it can be that three pressure sensors 6 are provided in each section to monitor the pressure changes along the way, and at the same time, the two pressure sensors 6 at the variable cross-section can detect the pressure changes caused by the carbon dioxide foam flowing through different interfaces. The data acquisition device 7 is not specifically limited in the embodiment of the present application, and it can be a computer, etc. In order to reduce the influence of temperature, a thermostat 8 and a temperature sensor 9 can also be provided, the core holder 5 is placed in the thermostat 8, the temperature sensor 9 is connected to the data acquisition device 7, and the temperature sensor 9 is used to detect the temperature in the thermostat 8. In order to ensure a constant pressure at the outlet, a back pressure controller 10 is also included. The back pressure controller 10 is arranged at the outlet of the core holder 5. The back pressure controller 10 is used to ensure a constant pressure at the outlet. Furthermore, a fluid extraction device 11 is also included. The fluid extraction device 11 is used to collect liquid flowing out of the outlet of the core holder 5.

[0046] In order to better understand the present application, the following is an application scenario of the critical velocity measurement device for the generation and propagation of carbon dioxide foam: (1) Determine the permeability distribution state of the core: According to actual needs, configure cores with different permeability characteristics, and then combine them into the core holder to simulate different formation types. (2) Determine the critical velocity (minimum apparent velocity) required for foam generation in section A: Configure a surfactant solution of a certain concentration, inject the surfactant solution and carbon dioxide gas at a certain rate at the same time, and observe the changes in the pressure gauge of section A (with the smallest inner diameter); when the pressure gauge pressure of section A increases sharply, record the first injection rate of carbon dioxide injection and the second injection rate of surfactant solution injection at this time. (3) Determine the critical speed (minimum apparent velocity) of foam propagation in section B: When carbon dioxide foam has been generated in section A, appropriately increase the injection speed so that the pressure difference in section B (the pressure difference between the two ends of section B) is between 4 and 5 bar, and observe the pressure change in section B; if a sharp increase in pressure has been observed in section B at this time, reduce the injection speed; if the pressure continues to increase, it is impossible to determine the critical speed of foam propagation in section B, and it is necessary to measure the critical speed of foam propagation in section C; if foam is not generated in section B, continue to increase the injection speed and keep injecting for a period of time, observe the changes in the pressure gauge until a sharp increase in pressure occurs, and record the first injection speed and the second injection speed at this time. (4) Determine the critical speed (minimum apparent velocity) of foam propagation in section C: If the foam has been stably generated in section B, and the foam strength has not changed significantly after reducing the injection speed, it is necessary to determine the critical speed of foam propagation in section C. The specific steps are similar to step (3). Observe the moment when the pressure increases sharply and record the first injection speed and the second injection speed at this time. (5) Determine the critical speed of foam rupture: When the foam can stably exist in all three sections, gradually reduce the injection rate and observe the pressure changes in each section. When the pressure difference in a certain section is reduced by 5-10 times, it proves that the injection rate at this time is difficult to maintain stable foam. Foam rupture first occurs in section C. As the injection rate decreases, the pressure decreases gradually in section B, and finally in section A. (6) After completion, the cleaning device: first inject a certain chemical reagent into the core holder, then inject clean water to clean the surfactant, then use carbon dioxide gas to further remove the residual liquid, and finally use a vacuum pump to evacuate. Of course, the injection gas-liquid ratio or surfactant concentration can be changed to repeat steps (2) to (5) to determine the flow law characteristics of carbon dioxide foam under different injection conditions. The core permeability distribution can also be changed, and steps (2)-(6) can be repeated to determine the flow law characteristics of carbon dioxide foam under different reservoir parameters. In this way, the seepage law of carbon dioxide foam in porous media under different permeability reservoirs and different injection conditions can be mapped, and the theoretical limit of foam propagation can be determined, providing theoretical guidance for foam flooding to enhance oil recovery.

[0047] A critical speed measuring device for the generation and propagation of carbon dioxide foam provided in an embodiment of the present application includes a carbon dioxide gas cylinder, a surfactant solution device, an air mass flow meter, a displacement pump, a core clamp, a pressure sensor and a data acquisition device; the data acquisition device acquires in real time the first injection speed of carbon dioxide injected into the core clamp, the second injection speed of the surfactant solution injected into the core clamp, and the inlet pressure and outlet pressure of the core in the core clamp corresponding to the first injection speed and the second injection speed; the critical speed of generation and propagation of carbon dioxide foam in the core is determined according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure. By determining the critical speed of generation and propagation of carbon dioxide foam, a theoretical basis can be provided for the development of oil and gas reservoir foam injection, and then the optimal injection amount of carbon dioxide foam can be determined to maximize production benefits.

[0048] Based on the above embodiments, Figure 3 A flowchart of a critical speed measurement method for carbon dioxide foam generation and propagation provided in an embodiment of the present application, Figure 3 As shown, the critical speed measurement method includes:

[0049] S10: acquiring in real time a first injection rate of carbon dioxide into the core holder, a second injection rate of the surfactant solution into the core holder, and an inlet pressure and an outlet pressure of the core in the core holder corresponding to the first injection rate and the second injection rate.

[0050] S11: determining a critical speed of generation and a critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure and the outlet pressure.

[0051] In step S10, usually, as the first injection rate and the second injection rate change, the pressure at both ends of the core will change. The foam is generated in the core holder by gas-water co-injection, and the dryness of the foam is determined by the water-gas injection rate ratio:

[0052]

[0053] Among them, f g Q is the foam dryness; g is the first injection rate of carbon dioxide; Q w is the second injection rate of the surfactant solution.

[0054] In step S11, how to determine the critical generation speed and propagation speed of carbon dioxide foam in the core is as follows.

[0055] The first method is:

[0056] (1) calculating the superficial flow rate of carbon dioxide foam in the core according to the first injection rate, the second injection rate and the diameter of the core;

[0057]

[0058] Among them, u t is the superficial velocity; Q g is the first injection rate of carbon dioxide; Q w is the second injection rate of the surfactant solution; A is the diameter of the core.

[0059] (2) Calculate the pressure difference ΔP based on the inlet pressure and the outlet pressure; Figure 4 A graph showing the change of pressure difference over time provided in an embodiment of the present application.

[0060] (3) Determine the pressure difference change rate based on the current pressure difference and the historical pressure difference. When the pressure difference change rate reaches a preset value, determine the target apparent flow rate corresponding to the current pressure difference, and use the target apparent flow rate as the critical speed for the generation of carbon dioxide foam.

[0061] The second method is:

[0062] (1) The apparent flow rate of carbon dioxide in the core is calculated based on the first injection rate, the second injection rate and the diameter of the core; the specific method is the same as above.

[0063] (2) The pressure difference is calculated based on the inlet pressure and the outlet pressure, and the pressure gradient is determined based on the pressure difference and the diameter of the core; that is, the pressure gradient is the pressure difference divided by the diameter of the core.

[0064] (3) Obtaining a corresponding relationship diagram between the control apparent flow velocity and the control pressure gradient; determining whether the apparent flow velocity and the pressure gradient corresponding to the apparent flow velocity conform to the corresponding relationship diagram; if so, determining the critical speed of formation, critical speed of propagation and critical speed of rupture of carbon dioxide foam according to the corresponding relationship diagram. Figure 5 A corresponding relationship diagram of the apparent flow rate and the pressure gradient provided in the embodiment of the present application is as follows: Figure 5 As shown in FIG. 1 , the corresponding relationship between the apparent flow rate and the pressure gradient is similar to an S-shaped curve. The pressure gradient of the carbon dioxide foam calculated above and its corresponding apparent flow rate are distributed in the corresponding relationship diagram to determine whether it is close to the S-shaped curve. If so, the two inflection points of the S-shaped curve are the critical speed of carbon dioxide foam generation and the critical speed of rupture, and the critical speed of propagation is generally between the critical speed of generation and the critical speed of rupture. Figure 4 As shown, the apparent flow velocity corresponding to point D is the critical velocity for the generation of carbon oxide foam, the apparent flow velocity corresponding to point E is the critical velocity for the rupture of carbon oxide foam, and the apparent flow velocity corresponding to point F is the critical velocity for the propagation of carbon oxide foam.

[0065] The above is a detailed introduction to the critical velocity measurement device and method for the generation and propagation of carbon dioxide foam provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0066] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A device for measuring the critical velocity of carbon dioxide foam generation and propagation, characterized in that: Includes a carbon dioxide gas cylinder, a surfactant solution device, an air mass flow meter, a displacement pump, a core holder, a pressure sensor, and a data acquisition device; The carbon dioxide gas cylinder is connected to the inlet end of the core holder through a first pipeline, and the first pipeline is provided with the air mass flow meter, and the air mass flow meter is used to adjust a first injection speed of carbon dioxide injected into the core holder; The surfactant solution device is connected to the inlet end of the core holder through a second pipeline, and the second pipeline is provided with the displacement pump, and the displacement pump is used to adjust a second injection speed of the surfactant solution injected into the core holder; A core is arranged inside the core holder, and the pressure sensors are respectively arranged at both ends of the core, and the pressure sensors are used to monitor the inlet pressure and the outlet pressure of the core in real time when the carbon dioxide and the surfactant solution are injected into the core holder at the same time; The air mass flow meter, the displacement pump and the pressure sensor are respectively connected to the data acquisition device, and the data acquisition device is used to obtain the first injection rate, the second injection rate, and the inlet pressure and the outlet pressure corresponding to the first injection rate and the second injection rate in real time, so as to determine the critical speed of generation and the critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure and the outlet pressure; The core holder comprises a plurality of sub-core holders of different diameters, and along the inlet end to the outlet end of the core holder, the diameter of the latter sub-core holder is greater than the diameter of the former sub-core holder; Correspondingly, the core disposed inside the core holder includes a plurality of sub-cores with different diameters, and the pressure sensors are respectively disposed at both ends of each sub-core; It also includes a thermostatic box and a temperature sensor, wherein the core holder is placed in the thermostatic box, the temperature sensor is connected to the data acquisition device, and the temperature sensor is used to detect the temperature in the thermostatic box; It also includes a back pressure controller, which is arranged at the outlet end of the core holder and is used to ensure that the pressure at the outlet end is constant.

2. The critical speed measuring device for carbon dioxide foam generation and propagation according to claim 1, characterized in that: Also included is a fluid extraction device, which is used to collect liquid flowing out from the outlet end of the core holder.

3. A method for measuring the critical speed of carbon dioxide foam generation and propagation, using the critical speed measuring device for carbon dioxide foam generation and propagation according to claim 1 or 2, characterized in that: include: Real-time acquisition of a first injection rate of carbon dioxide into a core holder, a second injection rate of a surfactant solution into the core holder, and an inlet pressure and an outlet pressure of a core in the core holder corresponding to the first injection rate and the second injection rate; Determine a critical speed of generation and a critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure, and the outlet pressure; The step of determining the critical speed of carbon dioxide foam generation in the core according to the first injection speed, the second injection speed, the inlet pressure, and the outlet pressure includes: Calculating the superficial flow rate of carbon dioxide foam in the core according to the first injection rate, the second injection rate and the diameter of the core; The superficial flow rate of the carbon dioxide foam in the core is calculated according to the first injection rate, the second injection rate and the diameter of the core, and includes: ； in, is the apparent flow velocity; is the first injection rate of carbon dioxide; is a second injection rate of the surfactant solution; is the diameter of the core; Calculate the pressure difference according to the inlet pressure and the outlet pressure; Determine a pressure difference change rate according to a current pressure difference and a historical pressure difference, and when the pressure difference change rate reaches a preset value, determine a target apparent flow rate corresponding to the current pressure difference, and use the target apparent flow rate as the critical speed for generating the carbon dioxide foam; Or, determining the critical speed of generation and critical speed of propagation of carbon dioxide foam in the core according to the first injection rate, the second injection rate, the inlet pressure, and the outlet pressure includes: Calculating the superficial flow rate of carbon dioxide in the core according to the first injection rate, the second injection rate and the diameter of the core; Calculating a pressure difference according to the inlet pressure and the outlet pressure, and determining a pressure gradient according to the pressure difference and the diameter of the core; Obtaining a corresponding relationship diagram between a control apparent flow velocity and a control pressure gradient; Determining whether the apparent flow velocity and the pressure gradient corresponding to the apparent flow velocity conform to the corresponding relationship diagram; If so, the critical generation speed and the critical propagation speed of the carbon dioxide foam are determined according to the corresponding relationship diagram.

4. The critical speed measurement method for carbon dioxide foam generation and propagation according to claim 3, characterized in that: After determining the critical speed of generation and critical speed of propagation of carbon dioxide foam in the core according to the first injection speed, the second injection speed, the inlet pressure and the outlet pressure, the method further includes: The critical bursting speed of the carbon dioxide foam is determined according to the corresponding relationship diagram.

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