CO 2 Simulation method, device and electronic equipment for phase change fracturing experiment

Abstract

The present invention discloses a simulation method, device and electronic device for a CO2 phase change fracturing experiment, and belongs to the technical field of drilling of soil layers or rocks. The method includes: obtaining the pressure of each stage of the CO2 phase change load in the CO2 phase change fracturing experiment, constructing the temperature-pressure relationship of the CO2 phase change load, calculating the temperature based on the temperature-pressure relationship, and using the calculated temperature as the simulated input temperature of CO2 to calculate the simulated initial viscosity of CO2, calculating the flow temperature of CO2 inside the matrix according to the simulated initial viscosity of CO2 and the mass conservation equation, using the flow temperature to update the flow viscosity of CO2 inside the matrix, and simulating the CO2 phase change fracturing experiment. The method can capture the influence of phase change that cannot be considered by traditional numerical models, and is more reliable, rapid and low-cost, and realizes the reproduction of the carbon dioxide phase change fracturing experiment, solving the problem of low efficiency and high cost of experimental research on CO2 phase change fracturing.

Description

Technical Field

[0001] The invention relates to the technical field of soil layer or rock drilling, and in particular to a simulation method, device and electronic equipment for a CO2 phase change fracturing experiment. Background Art

[0002] Compared with the traditional CO2 enhanced oil recovery technology, CO2 phase change fracturing technology is an emerging reservoir transformation technology. This technology injects CO2 into the reservoir at high pressure and high displacement during the fracturing stage, which can effectively improve the ability of CO2 to affect the nano-scale pore throats of shale. The artificial fractures caused by CO2 phase change can greatly increase the scope of CO2 action and enhance the effects of oil recovery and carbon sequestration.

[0003] However, CO2 phase change fracturing is still an emerging technology, and various experimental explorations are urgently needed, and its equipment and solutions must be optimized and improved in order to achieve field application as soon as possible. However, CO2 phase change fracturing experiments are difficult to conduct experimental explorations due to their high risks, strong uncontrollability, large volume, high experimental costs and long cycles, so researchers generally conduct simulations of CO2 phase change fracturing experiments first.

[0004] At present, in the simulation process of CO2 phase change fracturing experiment, CO2 phase change fracturing is achieved by applying an external load, but the influence of temperature and pressure on CO2 phase change fracturing is not considered in the whole process. However, the gas wedge effect of carbon dioxide cannot be ignored, especially the phase change that evolves with the temperature-pressure relationship in this process will greatly affect the fracturing results. Therefore, it is necessary to propose a numerical simulation method that can truly simulate the physical process of this phase change fracturing. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides the following technical solutions.

[0006] The first aspect of the present invention provides a method for simulating a CO2 phase change fracturing experiment, comprising:

[0007] Obtain the pressure at each stage of CO2 phase change load in CO2 phase change fracturing experiment;

[0008] The temperature-pressure relationship of the CO2 phase change load holding stage is constructed and expressed as:

[0009] ;

[0010] The temperature-pressure relationship of the CO2 phase change load reduction stage is constructed and expressed as:

[0011] ;

[0012] in, , and Calculated by the following formula:

[0013] ;

[0014] ;

[0015] ;

[0016] Calculated by the following formula:

[0017] ;

[0018] In the formula, is the boundary temperature of the CO2 phase change load holding stage; is the peak pressure of CO2 phase change load; is the boundary pressure during the CO2 phase change load decrease stage; T is the boundary temperature of the CO2 phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment; is about the second intermediate coefficient The function of is the boundary temperature at the beginning of the CO2 phase change load reduction stage; is the second control coefficient obtained through the BLEVE experiment;

[0019] Based on the temperature-pressure relationship of the CO2 phase change load maintenance stage and the temperature-pressure relationship of the CO2 phase change load reduction stage, the corresponding temperature is calculated and used as the simulation input temperature of CO2;

[0020] The simulated initial viscosity of CO2 is calculated using the simulated input temperature of CO2;

[0021] The flow temperature of CO2 inside the matrix is ​​calculated based on the simulated initial viscosity of CO2 and the mass conservation equation, and the flow viscosity of CO2 inside the matrix is ​​updated using the flow temperature;

[0022] The CO2 phase change fracturing experiment is simulated based on the flow viscosity of CO2 inside the matrix.

[0023] Preferably, the simulated initial viscosity of CO2 is calculated using the simulated input temperature of CO2 using the following formula:

[0024] ;

[0025] In the formula, To simulate the initial viscosity, is the zero density viscosity increment, is the gas viscosity increment, is the critical viscosity increment, is the gas compressibility factor ， is the critical density, is the critical temperature;

[0026] The calculation is done using the following formula:

[0027] ;

[0028] In the formula, About The function of , ;

[0029] The calculation is done using the following formula:

[0030] ;

[0031] In the formula, is a known coefficient;

[0032] The calculation is done using the following formula:

[0033] ;

[0034] In the formula, is a known coefficient, is the density of CO2, ;in is the real-time pressure at every point inside the sample, obtained by the fluid mass conservation equation, R is the gas constant, It is the real-time temperature of each point inside the sample, which is solved by the energy equation, and M is the molar constant of carbon dioxide;

[0035] The calculation is done using the following formula:

[0036] ;

[0037] In the formula, is a known coefficient.

[0038] Preferably, the simulation of the CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix includes: simulating the CO2 phase change fracturing experiment using a phase field method or a peri-field dynamics method.

[0039] The second aspect of the present invention provides a simulation device for a CO2 phase change fracturing experiment, comprising:

[0040] The pressure acquisition module is used to obtain the pressure of each stage of CO2 phase change load in the CO2 phase change fracturing experiment;

[0041] The temperature-pressure relationship building module is used to build the temperature-pressure relationship of the CO2 phase change load holding stage and express it as:

[0042] ;

[0043] The temperature-pressure relationship of the CO2 phase change load reduction stage is constructed and expressed as:

[0044] ;

[0045] in, , and Calculated by the following formula:

[0046] ;

[0047] ;

[0048] ;

[0049] Calculated by the following formula:

[0050] ;

[0051] In the formula, is the boundary temperature of the CO2 phase change load holding stage; is the peak pressure of CO2 phase change load; is the boundary pressure during the CO2 phase change load decrease stage; T is the boundary temperature of the CO2 phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment; is about the second intermediate coefficient The function of is the boundary temperature at the beginning of the CO2 phase change load reduction stage; is the second control coefficient obtained through the BLEVE experiment;

[0052] The analog input temperature calculation module is used to calculate the corresponding temperature based on the temperature-pressure relationship in the CO2 phase change load holding stage and the temperature-pressure relationship in the CO2 phase change load decreasing stage, and use the calculated temperature as the analog input temperature of CO2;

[0053] A simulated initial viscosity calculation module is used to calculate the simulated initial viscosity of CO2 using the simulated input temperature of CO2;

[0054] A flow temperature and flow viscosity calculation and updating module is used to calculate the flow temperature of CO2 inside the matrix according to the simulated initial viscosity of CO2 and the mass conservation equation, and to update the flow viscosity of CO2 inside the matrix using the flow temperature;

[0055] The experimental simulation module is used to simulate the CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix.

[0056] Preferably, the simulated initial viscosity of CO2 is calculated using the simulated input temperature of CO2 using the following formula:

[0057] ;

[0058] In the formula, To simulate the initial viscosity, is the zero density viscosity increment, is the gas viscosity increment, is the critical viscosity increment, is the gas compressibility factor ， is the critical density, is the critical temperature;

[0059] The calculation is done using the following formula:

[0060] ;

[0061] In the formula, About The function of , ;

[0062] The calculation is done using the following formula:

[0063] ;

[0064] In the formula, is a known coefficient;

[0065] The calculation is done using the following formula:

[0066] ;

[0067] In the formula, is a known coefficient, is the density of CO2, ;in is the real-time pressure at every point inside the sample, obtained by the fluid mass conservation equation, R is the gas constant, It is the real-time temperature of each point inside the sample, which is solved by the energy equation, and M is the molar constant of carbon dioxide;

[0068] The calculation is done using the following formula:

[0069] ;

[0070] In the formula, is a known coefficient.

[0071] Preferably, the simulation of the CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix includes: simulating the CO2 phase change fracturing experiment using a phase field method or a peri-field dynamics method.

[0072] A third aspect of the present invention provides a memory storing a plurality of instructions, wherein the instructions are used to implement the simulation method of the CO2 phase change fracturing experiment as described in the first aspect.

[0073] A fourth aspect of the present invention provides an electronic device, comprising a processor and a memory connected to the processor, wherein the memory stores a plurality of instructions, and the instructions can be loaded and executed by the processor so that the processor can execute the simulation method of the CO2 phase change fracturing experiment as described in the first aspect.

[0074] The beneficial effects of the present invention are as follows: the present invention proposes a solution to carry out numerical simulation to explore and optimize the problems of low efficiency and high cost in experimental research on CO2 phase change fracturing. The simulation method provided by the present invention can capture the influence of phase change that cannot be considered by traditional numerical models, and is more reliable, rapid, and low-cost, and can achieve the reproduction of carbon dioxide phase change fracturing experiments, and can simulate experiments under extreme conditions; if there are related experiments, they can also be updated in conjunction with the related experiments to meet the experimental requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is a schematic flow chart of the simulation method of the CO2 phase change fracturing experiment of the present invention;

[0076] Figure 2 This is a functional structure diagram of the simulation device for the CO2 phase change fracturing experiment of the present invention;

[0077] Figure 3 is a schematic diagram of a disk in a specific embodiment;

[0078] Figure 4 Schematic diagram of crack, temperature and pressure distribution in a specific embodiment;

[0079] Figure 5 It is a schematic diagram of the relationship between the temperature-pressure data of the load-holding stage of the real experiment and the temperature-pressure curve of the load-holding stage in the simulation process of the present invention;

[0080] Figure 6 It is a schematic diagram of the relationship between the temperature-pressure data of the load reduction stage in the real experiment and the temperature-pressure curve of the load reduction stage in the simulation process of the present invention. DETAILED DESCRIPTION

[0081] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0082] The method provided by the present invention can be implemented in the following terminal environment, and the terminal may include one or more of the following components: a processor, a memory, and a display screen. The memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the method described in the following embodiment.

[0083] The processor may include one or more processing cores. The processor uses various interfaces and lines to connect various parts of the entire terminal, and executes various functions of the terminal and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory, and calling data stored in the memory.

[0084] The memory may include random access memory (RAM) or read-only memory (ROM). The memory may be used to store instructions, programs, codes, code sets or instructions.

[0085] The display screen is used to display the user interface of each application.

[0086] In addition, those skilled in the art can understand that the structure of the above terminal does not constitute a limitation on the terminal, and the terminal may include more or fewer components, or combine certain components, or arrange the components differently. For example, the terminal also includes components such as a radio frequency circuit, an input unit, a sensor, an audio circuit, and a power supply, which will not be described in detail here.

[0087] Embodiment 1

[0088] like Figure 1 As shown, an embodiment of the present invention provides a simulation method for a CO2 phase change fracturing experiment, comprising:

[0089] S101, obtaining the pressure of each stage of CO2 phase change load in the CO2 phase change fracturing experiment;

[0090] S102, construct the temperature-pressure relationship of the CO2 phase change load holding stage and express it as:

[0091] ;

[0092] The temperature-pressure relationship of the CO2 phase change load reduction stage is constructed and expressed as:

[0093] ;

[0094] in, , and Calculated by the following formula:

[0095] ;

[0096] ;

[0097] ;

[0098] Calculated by the following formula:

[0099] ;

[0100] In the formula, is the boundary temperature of the CO2 phase change load holding stage; is the peak pressure of CO2 phase change load; is the boundary pressure during the CO2 phase change load decrease stage; T is the boundary temperature of the CO2 phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment (Boiling Liquid Expanding Vapor Explosion Experiment); is about the second intermediate coefficient The function of is the boundary temperature at the beginning of the CO2 phase change load reduction stage; is the second control coefficient obtained by the BLEVE experiment; in one embodiment of the present invention, The value of can be , , , , and can also be obtained from experiments for special conditions value. The value of can be: , , , and can also be obtained from experiments for special conditions value.

[0101] S103, calculating the corresponding temperature based on the temperature-pressure relationship of the CO2 phase change load maintenance stage and the temperature-pressure relationship of the CO2 phase change load reduction stage, and using the calculated temperature as the simulation input temperature of CO2;

[0102] S104, calculating the simulated initial viscosity of CO2 using the simulated input temperature of CO2;

[0103] S105, calculating the flow temperature of CO2 inside the matrix according to the simulated initial viscosity of CO2 and the mass conservation equation, and updating the flow viscosity of CO2 inside the matrix using the flow temperature;

[0104] S106, simulating a CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix.

[0105] The simulated initial viscosity of CO2 can be calculated by using the simulated input temperature of CO2 using the following formula:

[0106] ;

[0107] In the formula, To simulate the initial viscosity, is the zero density viscosity increment, is the gas viscosity increment, is the critical viscosity increment, is the gas compressibility factor ， is the critical density, is the critical temperature; in one embodiment of the present invention, =1, , .

[0108] The calculation is done using the following formula:

[0109] ;

[0110] In the formula, About The function of , ;

[0111] The calculation is done using the following formula:

[0112] ;

[0113] In the formula, is a known coefficient; in one embodiment of the present invention, The values ​​are: , , , , .

[0114] The calculation is done using the following formula:

[0115] ;

[0116] In the formula, is a known coefficient, is the density of CO2, :in is the real-time pressure at every point inside the sample, obtained by the mass conservation equation, R is the gas constant, is the real-time temperature of each point inside the sample, which is solved by the energy equation, and M is the molar constant of carbon dioxide; in one embodiment of the present invention, The values ​​are: , , , .

[0117] The energy equation is:

[0118] ;

[0119] is the latent heat of phase change, is the phase change mass source term, is the gradient operator, is the thermal conductivity coefficient, is the coefficient related to fracture, is the effective heat capacity of the porous medium, For time, is the bulk modulus of the solid, is the heat flux, is the volumetric strain.

[0120] The mass conservation equation is:

[0121] ;

[0122] Among them, the coefficient Determined using the following formula:

[0123] ;

[0124] in, is the porosity, is the heat transfer coefficient of CO2, is the heat transfer coefficient of the solid, is the effective density of CO2, is the phase change mass source term, is the CO2 flow rate, is the mass source term, is the Biot coefficient, is an interpolation function related to the fracture; the CO2 flow velocity is solved using the following formula:

[0125] ;

[0126] In the formula, is the effective permeability, To simulate the initial viscosity.

[0127] The calculation is done using the following formula:

[0128] ;

[0129] In the formula, is a known coefficient. In one embodiment of the present invention, The values ​​are: , , , , , , .

[0130] In a preferred embodiment of the present invention, the simulation of the CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix includes: the simulation of the CO2 phase change fracturing experiment can be performed using a phase field method or a peri-field dynamics method.

[0131] In one embodiment of the present invention, in step S101, the pressure of each stage of the CO2 phase change load in the CO2 phase change fracturing experiment is obtained, and the following expression of the carbon dioxide phase change load can be established according to the experimental results:

[0132] ;

[0133] in, Represents time, Indicates the duration of the holding phase. represents the load magnitude during the holding phase, represents the peak pressure, It represents the decay time (i.e. the time of the decline phase) during which the peak pressure becomes zero. It indicates the speed of load drop, which can be set to 400, or it can be fine-tuned according to specific experimental monitoring. The above parameters can be selected independently for exploration.

[0134] Since CO2 phase change fracturing experiments are high risk, uncontrollable and large in size, the cost of doing experiments is extremely high and the cycle is very long. Experimental research alone is inefficient and costly. The simulation method provided by the present invention can capture the effects of phase changes that traditional numerical models cannot consider, and is more reliable, rapid and low-cost, and can reproduce carbon dioxide phase change fracturing experiments and simulate experiments under extreme conditions; if there are related experiments, they can also be updated in conjunction with related experiments to meet experimental requirements.

[0135] Embodiment 2

[0136] like Figure 2 As shown, another aspect of the present invention also includes a functional module architecture that is completely consistent with the aforementioned method flow, that is, the embodiment of the present invention also provides a simulation device for a CO2 phase change fracturing experiment, including:

[0137] The pressure acquisition module 201 is used to obtain the pressure of each stage of the CO2 phase change load in the CO2 phase change fracturing experiment;

[0138] The temperature-pressure relationship building module 202 is used to build the temperature-pressure relationship of the CO2 phase change load holding stage and express it as:

[0139] ;

[0140] The temperature-pressure relationship of the CO2 phase change load reduction stage is constructed and expressed as:

[0141] ;

[0142] in, , and Calculated by the following formula:

[0143] ;

[0144] ;

[0145] ;

[0146] Calculated by the following formula:

[0147] ;

[0148] In the formula, is the boundary temperature of the CO2 phase change load holding stage; is the peak pressure of CO2 phase change load; is the boundary pressure during the CO2 phase change load decrease stage; T is the boundary temperature of the CO2 phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment; is about the second intermediate coefficient The function of is the boundary temperature at the beginning of the CO2 phase change load reduction stage; is the second control coefficient obtained through the BLEVE experiment;

[0149] The analog input temperature calculation module 203 is used to calculate the corresponding temperature based on the temperature-pressure relationship of the CO2 phase change load maintenance stage and the temperature-pressure relationship of the CO2 phase change load reduction stage, and use the calculated temperature as the analog input temperature of CO2;

[0150] A simulated initial viscosity calculation module 204 is used to calculate the simulated initial viscosity of CO2 using the simulated input temperature of CO2;

[0151] A flow temperature and flow viscosity calculation and updating module 205 is used to calculate the flow temperature of CO2 inside the matrix according to the simulated initial viscosity of CO2 and the mass conservation equation, and to update the flow viscosity of CO2 inside the matrix using the flow temperature;

[0152] The experimental simulation module 206 is used to simulate the CO2 phase change fracturing experiment based on the flow viscosity of CO2 inside the matrix.

[0153] The device can be implemented by the simulation method of the CO2 phase change fracturing experiment provided in the above-mentioned embodiment 1. The specific implementation method can be found in the description of embodiment 1, which will not be repeated here.

[0154] In a specific embodiment, for example, in an application scenario where a disk is broken, a disk with a diameter of 1 m, a thickness of 1 m, and a 20 mm prefabricated circular hole in the middle can be provided. Figure 3 As shown. The load is evenly distributed around the prefabricated circular hole. P and T The boundary relationship is updated using the method provided in the present invention (wherein, is the boundary pressure during the CO2 phase change load decrease stage; T is the boundary temperature of the CO2 phase change load reduction stage), the initial Set to 60MPa, Set to 0.5ms, The time interval is set to 10ms, and the CO2 phase change fracturing experiment is simulated according to the method provided by the present invention, and finally the cracks generated inside the disk under the carbon dioxide phase change condition are obtained, and the temperature and pressure of each point inside the disk are calculated. Finally, the simulated temperature field distribution, simulated fluid pressure distribution, simulated crack distribution and experimental crack distribution are obtained as shown in the figure. Figure 4 As shown. Figure 4 It can be seen that the simulation can well reproduce the experimental phenomenon, and successfully capture the temperature and pressure changes based on the reproduction experiment, proving the effectiveness of the present invention. The present invention uses the real evolution of the temperature and pressure relationship as the boundary condition, and successfully realizes the capture of the process of carbon dioxide phase change fracturing, including the evolution of temperature and pore pressure, which can clarify the fracturing effect of carbon dioxide in the matrix, and can capture the phase transition process of carbon dioxide based on relevant information, providing experimental ideas for the study of carbon dioxide phase change fracturing.

[0155] In order to further verify the effectiveness of the present invention, a series of real experiments of carbon dioxide phase change fracturing (including Experiment 1 to Experiment 4) were carried out in this embodiment and experimental data were obtained, including the temperature and pressure in carbon dioxide phase change fracturing. Figure 5 , using the temperature-pressure relationship of the CO2 phase change load holding stage in the present invention:

[0156]

[0157] Directly draw the expression curve, and draw the experimental scatter points (including the results of Experiment 1, Experiment 2, and Experiment 3) together with the expression curve to obtain Figure 5 , which can be used to observe whether the simulation curve is consistent with the experimental data.

[0158] for Figure 6 , part of the invention is compiled into code form, including the following formula:

[0159] The temperature-pressure relationship of the CO2 phase change load reduction stage is constructed and expressed as:

[0160] ;

[0161] in, , and Calculated by the following formula:

[0162] ;

[0163] ;

[0164] ;

[0165] Calculated by the following formula:

[0166] ;

[0167] set up The sizes correspond to four experiments, with specific values ​​of 33.8MPa, 43.1Mpa, 58.7MPa and 76.2MPa. Solve the above equations using the code and get Figure 6 Simulated temperature-pressure curve.

[0168] The simulated temperature and pressure curves of each experiment were obtained (such as Figure 5 and Figure 6 In the load holding stage, the simulated temperature and pressure curve obtained by the present invention (such as Figure 5 As shown in the figure, the data detected by the experiment can be well described; in the load reduction stage, for different experiments from Experiment 1 to Experiment 4, the simulated temperature and pressure curves obtained by the present invention (as shown in the figure) Figure 6 The curve shown in ) can also well describe the corresponding experimental data. Therefore, according to the experimental data obtained from the real experiment and the corresponding simulated temperature and pressure curve obtained by the method of the present invention (such as Figure 5 and 6 The relationship between the two (as shown) verifies the effectiveness and reliability of the scheme of the present invention. Among them, the implementation process of Experiments 1 to 4 is:

[0169] Carbon dioxide is filled into the phase change experimental device under high pressure, with a heating rod at the head and an energy release device at the tail. A pressure sensor and a temperature sensor are set at the energy release at the tail to detect temperature and pressure changes during the experiment. After carbon dioxide is filled, the heating rod works and the temperature rises by 700°C, causing the internal carbon dioxide to boil and rush out from the energy release. During this period, the pressure sensor and temperature sensor are used for monitoring to obtain the relationship between temperature and pressure changes over time.

[0170] The present invention also provides a memory storing a plurality of instructions, wherein the instructions are used to implement the simulation method of the CO2 phase change fracturing experiment as described in the first embodiment.

[0171] The present invention also provides an electronic device, comprising a processor and a memory connected to the processor, wherein the memory stores a plurality of instructions, and the instructions can be loaded and executed by the processor so that the processor can execute the simulation method of the CO2 phase change fracturing experiment as described in Example 1.

[0172] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. CO 2 Simulation method of phase change fracturing experiment, It is characterized in that include: Obtain CO 2 CO in phase change fracturing experiments 2 Pressure at each stage of phase change load; Building CO 2 The temperature-pressure relationship in the phase change load holding stage is expressed as: ； Building CO 2 The temperature-pressure relationship in the phase change load reduction stage is expressed as: ； in, , and Calculated by the following formula: ； ； ； Calculated by the following formula: ； In the formula, is a natural constant, For CO 2 Boundary temperature during the phase change load holding stage; For CO 2 Peak pressure of phase change load; For CO 2 Boundary pressure during the phase change load drop stage; T For CO 2 Boundary temperature during the phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment; is about the second intermediate coefficient The function of For CO 2 The boundary temperature at the beginning of the phase change load drop stage; is the second control coefficient obtained through the BLEVE experiment; Based on CO 2 Temperature-pressure relationship and CO in the phase change load holding stage 2 The corresponding temperature is calculated by the temperature-pressure relationship in the phase change load reduction stage, and the calculated temperature is used as the CO 2 The analog input temperature of Utilizing CO 2 The analog input temperature is used to calculate the CO 2 The simulated initial viscosity of According to CO 2 The simulated initial viscosity and mass conservation equations are used to calculate CO 2 The flow temperature inside the matrix is ​​used to update the CO 2 Flow viscosity within the matrix; Based on CO 2 The flow viscosity inside the matrix is ​​CO 2 Simulation of phase change fracturing experiment.

2. The CO according to claim 1 2 Simulation method of phase change fracturing experiment, It is characterized in that The use of CO 2 The analog input temperature is used to calculate the CO 2 The simulated initial viscosity is calculated using the following formula: ； In the formula, To simulate the initial viscosity, is the zero density viscosity increment, is the gas viscosity increment, is the critical viscosity increment, is the gas compressibility factor ， is the critical density, is the critical temperature; The calculation is done using the following formula: ； In the formula, About The function of , ; The calculation is done using the following formula: ； In the formula, is a known coefficient; The calculation is done using the following formula: ； In the formula, is a known coefficient, For CO 2 The density of ;in is the real-time pressure at every point inside the sample, obtained by the mass conservation equation, R is the gas constant, It is the real-time temperature of each point inside the sample, which is solved by the energy equation, and M is the molar constant of carbon dioxide; The calculation is done using the following formula: ； In the formula, is a known coefficient.

3. The CO according to claim 1 2 Simulation method of phase change fracturing experiment, It is characterized in that The CO-based 2 The flow viscosity inside the matrix is ​​CO 2 The simulation of phase change fracturing experiment includes: using phase field method or peridynamic method to simulate CO 2 Simulation of phase change fracturing experiment. 4.CO 2 Simulation device for phase change fracturing experiment, It is characterized in that include: Pressure acquisition module for obtaining CO 2 CO in phase change fracturing experiments 2 Pressure at each stage of phase change load; Temperature-pressure relationship building blocks for building CO 2 The temperature-pressure relationship in the phase change load holding stage is expressed as: ； Building CO 2 The temperature-pressure relationship in the phase change load reduction stage is expressed as: ； in, , and Calculated by the following formula: ； ； ； Calculated by the following formula: ； In the formula, is a natural constant, For CO 2 Boundary temperature during the phase change load holding stage; For CO 2 Peak pressure of phase change load; For CO 2 Boundary pressure during the phase change load drop stage; T For CO 2 Boundary temperature during the phase change load reduction stage; is the first intermediate coefficient, is the first control coefficient obtained through the BLEVE experiment; is about the second intermediate coefficient The function of For CO 2 The boundary temperature at the beginning of the phase change load drop stage; is the second control coefficient obtained through the BLEVE experiment; Analog input temperature calculation module for CO based 2 Temperature-pressure relationship and CO in the phase change load holding stage 2 The corresponding temperature is calculated by the temperature-pressure relationship in the phase change load reduction stage, and the calculated temperature is used as the CO 2 The analog input temperature of Simulation initial viscosity calculation module for using CO 2 The analog input temperature is used to calculate the CO 2 The simulated initial viscosity of Flow temperature and flow viscosity calculation update module for CO 2 The simulated initial viscosity and mass conservation equations are used to calculate CO 2 The flow temperature inside the matrix is ​​used to update the CO 2 Flow viscosity within the matrix; Experimental simulation module for CO 2 The flow viscosity inside the matrix is ​​CO 2 Simulation of phase change fracturing experiment.

5. The CO according to claim 4 2 Simulation device for phase change fracturing experiment, It is characterized in that The use of CO 2 The analog input temperature is used to calculate the CO 2 The simulated initial viscosity is calculated using the following formula: ； In the formula, To simulate the initial viscosity, is the zero density viscosity increment, is the gas viscosity increment, is the critical viscosity increment, is the gas compressibility factor ， is the critical density, is the critical temperature; The calculation is done using the following formula: ； In the formula, About The function of , ; The calculation is done using the following formula: ； In the formula, is a known coefficient; The calculation is done using the following formula: ； In the formula, is a known coefficient, For CO 2 The density of ;in is the real-time pressure at every point inside the sample, obtained by the fluid mass conservation equation, R is the gas constant, It is the real-time temperature of each point inside the sample, which is solved by the energy equation, and M is the molar constant of carbon dioxide; The calculation is done using the following formula: ； In the formula, is a known coefficient.

6. The CO according to claim 4 2 Simulation device for phase change fracturing experiment, It is characterized in that The CO-based 2 The flow viscosity inside the matrix is ​​CO 2 The simulation of phase change fracturing experiment includes: using phase field method or peridynamic method to simulate CO 2 Simulation of phase change fracturing experiment.

7. A memory, It is characterized in that A plurality of instructions are stored, and the instructions are used to implement the CO according to any one of claims 1 to 3. 2 Simulation method of phase change fracturing experiment.

8. An electronic device, It is characterized in that The invention comprises a processor and a memory connected to the processor, wherein the memory stores a plurality of instructions, and the instructions can be loaded and executed by the processor so that the processor can execute the CO according to any one of claims 1 to 3. 2 Simulation method of phase change fracturing experiment.

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