A simulation method and system for heat transfer performance in a near well region considering THMC coupling

Abstract

This application belongs to the field of heat transfer simulation and calculation technology, and discloses a method and system for simulating near-wellbore heat transfer performance considering THMC coupling. The method includes: generalizing an ultra-long gravity heat pipe into multiple independent heat pipe segments to construct a gravity heat pipe unit model; establishing a multi-field coupling model of temperature field, seepage field, mechanical field, and chemical field (THMC) and a dynamic calculation model of fracture aperture; setting initial conditions or boundary conditions for each physical field; meshing and solving the gravity heat pipe unit model; updating the fracture aperture in real time during the heat extraction process to obtain the distribution of multi-physics fields and the temporal change of heat extraction power in the near-wellbore area. This application can accurately simulate the dynamic evolution of fracture aperture under multi-field coupling, improving the accuracy of heat extraction effect evaluation and heat transfer enhancement scheme prediction.

Description

Technical Field

[0001] This application relates to the field of heat transfer simulation and calculation technology, and in particular to a method and system for simulating near-wellbore heat transfer performance considering THMC coupling. Background Technology

[0002] Global climate change and other issues have made people increasingly aware of the importance of sustainable development. Currently, humanity faces the challenge of striking a balance between economic and social development and ecological environmental protection. Geothermal energy, as a new energy source, is attracting increasing attention due to its zero-carbon emissions, wide distribution, stability, and high efficiency. Currently, the main methods for developing and utilizing deep geothermal energy include well-circulation heat extraction technology, single-well closed-loop heat extraction technology, and gravity heat pipe circulation heat extraction technology.

[0003] Ultra-long gravity heat pipes are an emerging deep geothermal extraction technology. Their core principle involves establishing a closed working fluid circulation system within a borehole. Utilizing the phase change process of the working fluid absorbing heat and evaporating at the bottom, and condensing and releasing heat at the top, this achieves efficient "pump-free" extraction of deep geothermal energy. This technology avoids the high energy consumption and maintenance difficulties associated with traditional geothermal extraction methods that rely on mechanical pumps for fluid transport, providing a highly promising new approach for developing deep and dry hot rock geothermal resources. Gravity heat pipe circulation heat extraction technology transfers heat energy from the reservoir to the surface through phase change processes (evaporation and condensation). However, due to challenges such as evaporation inhibition and low heat transfer efficiency in deep geothermal development, reservoir modification and heat transfer enhancement are necessary to improve thermal extraction efficiency. In 2022, the Institute of Hydrogeology and Environmental Geology of the Chinese Academy of Geological Sciences, in collaboration with the Guangzhou Institute of Energy Research of the Chinese Academy of Sciences, conducted a field geothermal energy extraction test at borehole D34 in Xiong'an New Area. A 4200-meter gravity heat pipe experimental device was constructed, and for the first time, ammonia was used as the working fluid for circulating heat extraction, enabling long-distance transmission of geothermal energy from the well bottom to the surface. The test lasted three months, with a short-term single-well heat extraction power reaching 1.3 MW and an average heat extraction power of 800 kW. Long-term stable operation can support a heating area of ​​over 20,000 square meters.

[0004] During gravity heat pipe heat extraction, the interaction between the temperature field, seepage field, mechanical field, and chemical field within the reservoir affects the heat extraction efficiency. Natural convection processes in geothermal reservoirs can enhance the heat extraction effect of the heat pipe. Changes in the reservoir's mechanical and chemical fields during geothermal development can alter the fracture opening and change the reservoir's seepage characteristics. Taron et al. established a dual-medium THMC coupled model to simulate an enhanced geothermal system composed of injection wells and production wells. Gan et al. controlled porosity and reservoir permeability by simulating the dissolution and precipitation of reservoir minerals, and thereby explored the potential feasibility of supercritical carbon dioxide as a working fluid in geothermal reservoirs. Previous heat transfer enhancement technologies for near-wellbore areas mainly include hydraulic fracturing, high thermal conductivity material filling, and fracturing and fracture filling technologies, which can be broadly classified into conduction-based enhancement schemes and convection-based enhancement schemes in principle.

[0005] Previous studies on multi-field coupled numerical simulations of geothermal reservoirs have mainly focused on hydrothermal extraction processes and enhanced geothermal system extraction models, with relatively little research on near-wellbore multi-field coupled processes in gravity heat pipe heat extraction. For heat pipe heat extraction models with extremely high aspect ratios, existing solutions primarily involve using sparse grids in the vertical direction. This generalized approach cannot accurately characterize the fractures within the reservoir, thus reducing computational accuracy. Furthermore, there is a lack of systematic research on the impact of multi-field coupled processes, such as fracture aperture changes caused by temperature variations during heat pipe heat extraction, on heat extraction efficiency. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a near-wellbore heat transfer performance simulation method and system that considers THMC coupling. This method addresses the technical problem in existing gravity heat pipe heat extraction simulations that fail to adequately consider the influence of fracture geometry parameters and heat transfer enhancement schemes on heat extraction efficiency. Taking a single gravity heat pipe unit as the research object, a THMC multi-field coupling model is established to explore the influence of fracture inclination angle and opening. The effects of conduction-type and convection-type near-wellbore heat transfer enhancement schemes are compared and analyzed, thereby providing a theoretical basis for improving the heat extraction efficiency of a single gravity heat pipe.

[0007] According to the first aspect of this application, a method for simulating near-wellbore heat transfer coupling in gravity heat pipe heat recovery is provided, the method comprising: The ultra-long gravity heat pipe is generalized into multiple independent heat pipe segments, and a gravity heat pipe unit model is constructed for each heat pipe segment and the surrounding rock near the well within a predetermined radial range. A multi-field coupled THMC model including multiple physical fields is constructed, considering the coupling effect between the physical fields, and a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture is established; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field; Based on the actual geological parameters and heat recovery conditions of the target reservoir, the initial or boundary conditions of the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model are set respectively. The gravity heat pipe unit model is meshed, and the THMC multi-field coupling model is solved based on the initial and boundary conditions. The fracture opening is updated in real time during the heat extraction process through the fracture opening dynamic calculation model, so as to obtain the multi-physics field distribution and time-series change of heat extraction power in the near-wellbore area during the heat extraction process.

[0008] Furthermore, in the seepage field of the THMC multi-field coupling model, the seepage process in the matrix is ​​represented as follows: in, For fluid density; Reservoir porosity; For time; The fluid velocity; For gradient operators; fluid velocity The calculation formula is: in, Reservoir permeability; The fluid dynamic viscosity coefficient; For fluid pressure; It is a gravity term; For fluid density; It is the acceleration due to gravity; z Vertical depth; The mass conservation equation for the fluid in the fracture is as follows: in, The crack opening; For fluid density; The fluid velocity in the crack; For time; The porosity is the fracture porosity. The gradient operator for the tangential plane of the crack; The mass flow rate through the crack; In the temperature field within the reservoir, the heat balance within the reservoir can be expressed as: in, and These are the equivalent heat capacity and equivalent thermal conductivity; Rock temperature; For time; For gradient operators; Represents the heat convection term. Represents the heat conduction term; For the heat transferred; Equivalent heat capacity and equivalent thermal conductivity are defined as follows: in, and Density of solids and fluids; and For the heat capacity of solids and fluids (J / (kg·K)); and It is the thermal conductivity of solids and fluids.

[0009] In a mechanical field, a linear elastic model is used to describe the elastic deformation of the fracture surface: in, Effective stress; and These are the tangential and normal stresses; and Stiffness in the tangential and normal directions; and For tangential and normal displacements; In a chemical field, the transport process of dilute substances is described by the following convection-dispersion equation: in, The concentration of the solute in the fluid; The fluid diffusion coefficient; This represents the fluid velocity.

[0010] Furthermore, considering the coupling effects between various physical fields, the influence of temperature changes on fluid properties can be described as follows: in, The density of water is affected by temperature; The viscosity of water is affected by temperature; The thermal conductivity of water under the influence of temperature; The heat capacity of water under the influence of temperature.

[0011] Furthermore, considering the coupling effect between various physical fields, the change in crack aperture caused by the mechanical field is expressed as: in, The change in crack aperture caused by the mechanical field; The stress is in the normal direction; Stiffness in the normal direction; f This refers to fluid pressure.

[0012] Furthermore, considering the coupling effects between various physical fields, the crack aperture caused by chemical dissolution or precipitation... Determined by the following formula: in, Density of solid; This indicates the number of moles of silica per unit mass of rock. The reaction rate is determined by the following formula: in, The reaction rate; It is the reaction rate constant; To balance the concentration; This refers to the density of the solute. The equilibrium concentration is determined by the following formula: in, The temperature of the rock.

[0013] Furthermore, the dynamic calculation model for the fracture aperture is expressed as follows: in, The initial aperture of the fracture. The change in crack aperture caused by the mechanical field. The crack opening caused by chemical dissolution or precipitation.

[0014] Furthermore, based on the actual geological parameters and thermal recovery conditions of the target reservoir, initial or boundary conditions are set for the temperature field, seepage field, mechanical field, and chemical field within the reservoir in the gravity heat pipe unit model, including: The initial conditions of the temperature field are set according to the measured temperature at the current depth of the reservoir. The boundary conditions of the temperature field are: the periphery of the gravity heat pipe unit model is set as a constant temperature boundary, and the heat pipe is set as the boiling point temperature of the circulating working fluid. The boundary condition for the seepage field is: the periphery of the gravity heat pipe unit model is set as a flow-free boundary; The boundary conditions of the mechanical field are: the four sides of the gravity heat pipe unit model are set as fixed constraints; The initial conditions of the chemical field are set as follows: the dissolution-precipitation equilibrium state at the current temperature.

[0015] According to the second technical solution of this application, a near-wellbore heat transfer coupling simulation system for gravity heat pipe heat recovery is provided, the system comprising: The heat pipe unit creation module is configured to generalize ultra-long gravity heat pipes into multiple independent heat pipe segments, and to construct gravity heat pipe unit models for a single heat pipe segment and the surrounding rock near the well within a predetermined radial range. The coupling calculation module is configured to construct a THMC multi-field coupling model that includes multiple physical fields, consider the coupling effect between the physical fields, and establish a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field; The condition setting module is configured to set the initial and boundary conditions of the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model according to the actual geological parameters and heat recovery conditions of the target reservoir. The model solving module is configured to mesh the gravity heat pipe unit model, solve the THMC multi-field coupling model based on the initial and boundary conditions, and update the fracture opening in real time during the heat extraction process through the fracture opening dynamic calculation model to obtain the multi-physics field distribution and time-series changes of heat extraction power in the near-wellbore area.

[0016] According to the third technical solution of this application, an electronic device is provided, the electronic device comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the method described above.

[0017] According to the fourth technical solution of this application, a non-transitory computer-readable storage medium storing instructions is provided, which, when executed by a processor, performs the method described above.

[0018] Based on the above-mentioned technical solution provided in this application, it has at least the following technical effects: This application generalizes ultra-long gravity heat pipes into multiple independent heat pipe segments and constructs a unit model of a fractured system. It establishes a four-field coupled model of temperature, seepage, mechanical, and chemical fields, and introduces a dynamic calculation model for fracture aperture by superimposing mechanical and chemical aperture. This model can update the changes in fracture aperture during heat extraction in real time and feed them back to the seepage and heat transfer fields. By fully considering the influence of multi-field coupling on fracture aperture, it avoids the error in heat transfer effect assessment caused by ignoring dynamic changes in fractures, significantly improving the accuracy of heat extraction power prediction. Based on this coupled model, it can quantitatively analyze the impact of fracture dip angle and initial aperture on heat extraction effect, and accurately predict the full-cycle heat extraction power changes of two near-wellbore heat transfer enhancement schemes (conduction and convection). This provides a reliable theoretical basis and technical support for improving the heat extraction efficiency of a single gravity heat pipe, and has important engineering guiding significance for the efficient development of deep geothermal resources.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 A flowchart illustrating a near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery, provided in this application embodiment; Figure 2 This is a schematic diagram of a gravity heat pipe heat extraction simulation unit provided in an embodiment of this application; Figure 3 This is a structural diagram of the gravity heat pipe unit model provided in the embodiments of this application; Figure 4 This is a schematic diagram of the mesh generation of a heat pipe unit model provided in an embodiment of this application; Figure 5 This is a schematic diagram of the near-well temperature field changes during heat pipe heat extraction, provided in an embodiment of this application. Figure 6 A schematic diagram illustrating the time-series variation of the heat pipe section's heat extraction power provided in an embodiment of this application; Figure 7 This is a schematic diagram of the fracture opening after 40 days of heat harvesting, provided in an embodiment of this application. Figure 8 A schematic diagram illustrating the effect of fissure opening variation on heat pipe section heat extraction power variation provided in an embodiment of this application; Figure 9 This is a schematic diagram illustrating the near-wellbore temperature field variation for different fracture dip angle models provided in this application embodiment; Figure 10Schematic diagram of heat extraction power variation curves under different fracture dip angles provided in the embodiments of this application; Figure 11 Schematic diagram of near-wellbore temperature field for different initial fracture aperture models provided in the embodiments of this application; Figure 12 A schematic diagram of the heat extraction power variation curves under different fracture opening conditions provided in the embodiments of this application; Figure 13 A schematic diagram of the heat collection power of a heat pipe section under different thermal conductivity of reinforcing materials provided in the embodiments of this application; Figure 14 A schematic diagram of the heat collection power of heat pipe sections under different enhanced radius ranges provided in the embodiments of this application; Figure 15 A schematic diagram of the heat collection power of a heat pipe section under different thermal conductivity of reinforcing materials provided in the embodiments of this application; Figure 16 A schematic diagram of the heat collection power of heat pipe sections under different enhanced radius ranges provided in the embodiments of this application; Figure 17 This is a structural diagram of a gravity heat pipe heat extraction near-wellbore heat transfer coupling simulation system provided in an embodiment of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solution of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: Ultra-long gravity heat pipes are an emerging deep geothermal extraction technology that enables "pump-free" extraction of deep geothermal resources. During heat extraction, the interaction between the temperature field, seepage field, mechanical field, and chemical field within the reservoir significantly impacts extraction efficiency. Therefore, this application provides a near-wellbore heat transfer coupling simulation method for gravity heat pipe extraction, used to achieve precise characterization of the near-wellbore fracture structure. By leveraging the dynamic changes in fracture aperture, the multi-field coupling process during gravity heat pipe extraction is accurately simulated. Two near-wellbore heat transfer enhancement schemes, conductive and convective, are designed to predict the heat extraction effect of the heat pipe. Results show that ignoring the changes in fracture aperture under multi-field coupling leads to significant errors in heat transfer effect assessment (relative error approximately 10.72~19.16% under operating conditions). The conductive enhancement scheme's heat transfer enhancement effect is evident throughout the entire extraction cycle, while the convective enhancement scheme's increased permeability mitigates the attenuation of extraction power by enhancing natural convection within the reservoir. The method described in this application provides theoretical support and technical approach for the efficient development and accurate prediction of geothermal resources.

[0023] Please see Figure 1This is a flowchart of a near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery provided in an embodiment of this application. The method includes the following steps S10-S40.

[0024] S10: The ultra-long gravity heat pipe is generalized into multiple independent heat pipe segments, and a gravity heat pipe unit model is constructed for each heat pipe segment and the surrounding rock near the well within a predetermined radial range.

[0025] Please see Figure 2 This is a schematic diagram of a gravity heat pipe heat extraction simulation unit provided in an embodiment of this application. Ultra-long gravity heat pipes used for geothermal extraction typically reach lengths of several kilometers. Studies have shown that the heat extraction effect of gravity heat pipes is mainly controlled by the near-wellbore rock strata, and its influence range usually does not exceed 10 m radially from the heat pipe. For such structures with extremely large aspect ratios, directly performing detailed geometric characterization and mesh generation in a full-size model will inevitably reduce the simulation accuracy perpendicular to the heat pipe direction, and may even lead to computational divergence. Existing studies often use the method of refining the horizontal mesh to alleviate this problem; however, this method still cannot fully consider the influence of heterogeneous geological features such as fractures developed in the near-wellbore area on the heat transfer process. To overcome the above limitations, this embodiment generalizes the ultra-long gravity heat pipe into multiple independent heat pipe segments.

[0026] In practical engineering, ultra-long gravity heat pipes are typically assembled from multiple heat pipe segments connected in series. In actual heat pipe mining projects, these segments are interconnected via steam, and their working pressures can be approximated as equal, resulting in a relatively consistent saturation temperature of the internal working fluid. However, due to significant differences in surrounding rock temperature at different depths, the heat extraction power of each heat pipe segment varies. Furthermore, methods such as fracturing and perforation to enhance reservoir heat transfer typically only modify a specific segment. This embodiment independently generalizes and models a single heat pipe segment and its near-wellbore surrounding rock (including fracture systems), defining the temperature boundary conditions as a function of depth. This approach effectively improves the model's ability to characterize geometric features and enhances computational accuracy. Specifically, it has the following two advantages: Reduced geometric generalization error: By decomposing the maximum aspect ratio problem into multiple sub-problems of conventional scale, it effectively avoids the numerical distortion problem caused by the excessive aspect ratio of the grid in the full-size model, and significantly improves the calculation accuracy and numerical stability; Achieves fine characterization of the near-wellbore area: The method can fully consider the geological characteristics of the near-wellbore surrounding rock of each heat pipe section, including the occurrence and aperture of fractures, and realize the accurate calculation of the multi-field coupling effect of thermo-hydraulic-mechanical-chemical (THMC) during thermal recovery.

[0027] Please see Figure 3This is a structural diagram of the gravity heat pipe unit model provided in the embodiments of this application. The structure of a single heat pipe model is based on a homogeneous rock matrix model, and the overall structure is a cylinder with a radius of 10m, with the heat extraction boundary of the gravity heat pipe at the center; and a fracture surface passing through the heat pipe well section is added, and the fracture structure is characterized by controlling the fracture dip angle.

[0028] S20: Construct a THMC multi-field coupling model that includes multiple physical fields, couple the interactions of each physical field, and establish a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field.

[0029] Gravity heat pipes do not directly extract groundwater; instead, they extract heat through evaporation and condensation processes within the pipe. In the evaporation section, heat within the rock is absorbed by the heat pipe to evaporate the working fluid. This process lowers the reservoir temperature, and the resulting temperature change causes natural convection due to density differences, altering the reservoir pressure. Simultaneously, temperature changes also affect the mechanical and chemical states of the reservoir. Therefore, the THMC four-field coupling effect is considered in the THMC multi-field coupling model. In the seepage field, the seepage process in the matrix is ​​controlled by Darcy's law, which can be expressed by the mass conservation equation as: in, Fluid density (kg / m³) 3 ); Reservoir porosity; Time (s); The fluid velocity is (m / s). This is the gradient operator.

[0030] According to Darcy's law, It can be described as: in, Reservoir permeability (m 2 ); is the hydrodynamic viscosity coefficient (Pa·s); Fluid pressure (Pa); It is the gravity term. Fluid density (kg / m³) 3 ), Acceleration due to gravity (m / s²) 2 ), z is the vertical depth (m).

[0031] The mass conservation equation for the fluid in the fracture is as follows: in, Crack aperture (mm); Fluid density (kg / m³) 3 ); The fluid velocity in the crack is (m / s). Time (s); The porosity is the fracture porosity. The gradient operator for the tangential plane of the crack; The mass flow rate (kg / s) through the crack.

[0032] In the temperature field within the reservoir, the heat balance can be described as follows: in, and Equivalent heat capacity (J / (m³)) 3 ·K) and equivalent thermal conductivity (W / (m·K)); Rock temperature (K); Time (s); For gradient operators; Represents the heat convection term. Represents the heat conduction term; The amount of heat transferred (W).

[0033] The equivalent specific heat capacity and equivalent thermal conductivity can be defined as follows: in, and Density of solids and fluids (kg / m³) 3 ); and For the heat capacity of solids and fluids (J / (kg·K)); and It is the thermal conductivity of solids and fluids (W / (m·K)).

[0034] The mechanical field considers the elastic deformation of the fracture under effective stress. A linear elastic model is used to describe the elastic deformation of the fracture surface: in, Effective stress (Pa); and The stresses (Pa) are in the tangential and normal directions. and Stiffness in the tangential and normal directions (Pa / m); and The displacements (m) are in the tangential and normal directions.

[0035] In a chemical field, the transport process of dilute substances can be described by the following convection-dispersion equation: in, The concentration of solute in the fluid (mol / m³) 3 ); The fluid diffusion coefficient (m) 2 / s); The fluid velocity is denoted as m / s.

[0036] The various physical fields are coupled and influence each other; temperature changes cause changes in properties such as fluid density, which in turn leads to convection processes within the reservoir, enhancing heat transfer; at the same time, temperature changes and convection processes alter the effective stress, causing elastic deformation and thermal strain in the rock mass, which in turn changes the fracture aperture and affects the convection process; in addition, temperature changes can also disrupt the mineral dissolution and precipitation equilibrium, thereby generating chemical aperture.

[0037] The effect of temperature changes on fluid properties can be described as follows: in, Density of water under the influence of temperature (kg / m³) 3 ); Viscosity of water under temperature influence (Pa·s); The thermal conductivity of water under the influence of temperature (W / (m·K)); The heat capacity of water under the influence of temperature (J / (kg·K)).

[0038] The change in fracture aperture caused by a mechanical field can be defined as: in, The change in crack aperture caused by the mechanical field; The stress is in the normal direction (Pa); Stiffness in the normal direction (Pa / m); f The fluid pressure is expressed in Pa.

[0039] Minerals in reservoirs exist in a natural dissolution-precipitation equilibrium. The reaction rate and equilibrium are affected by temperature, and the chemical reaction rate is defined as follows: in, Solid density (kg / m³) 3 ); This indicates the number of moles of silica per unit mass of rock. For the reaction rate, The reaction rate constant can be calculated using the Arrhenius equation; in, It is the Arrhenius constant; It is the activation energy of the reaction; is the molar gas constant.

[0040] To achieve equilibrium concentration, it can be considered a function of temperature: in, The temperature of the rock is K.

[0041] Chemical reaction processes also affect fracture aperture, which is related to the dissolution and precipitation of the main minerals in the reservoir. Therefore, chemical aperture is defined. Differential equations: in, The crack opening caused by chemical dissolution or precipitation; This indicates the number of moles of silicon dioxide per unit mass of rock.

[0042] Finally, considering the multi-field coupling, the change in fracture aperture (i.e., fracture aperture) can be expressed as: in, The initial aperture of the fracture. The change in crack aperture caused by the mechanical field. The crack opening caused by chemical dissolution or precipitation.

[0043] S30: Based on the actual geological parameters and heat recovery conditions of the target reservoir, set the initial or boundary conditions for the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model.

[0044] In this embodiment, the primary physical field of interest in the gravity heat pipe unit model is the temperature field. The initial conditions are set based on the measured temperature at the current reservoir depth. For boundary conditions, the boundaries around the model are set as constant temperature boundaries; the temperature at the heat pipe is set using the boiling point of the circulating working fluid. Regarding the flow field, the perimeter is set as a non-flow boundary, and the natural convection process caused by temperature changes is calculated within the reservoir. For the mechanical field, the perimeter is set as a fixed constraint, and stress changes and their impact on fracture aperture are calculated within the reservoir due to temperature changes and flow processes. The initial condition for the chemical field is set as the dissolution-precipitation equilibrium state at the current temperature, and the process of temperature changes affecting the chemical equilibrium and the impact of the chemical equilibrium on fracture aperture are calculated within the reservoir.

[0045] S40: Mesh the gravity heat pipe unit model, solve the THMC multi-field coupling model based on initial and boundary conditions, and update the fracture opening in real time during the heat extraction process through the fracture opening dynamic calculation model to obtain the multi-physics field distribution and time-series change of heat extraction power in the near-wellbore area during the heat extraction process.

[0046] In this embodiment, the main parameters used in the gravity heat pipe unit model are shown in Table 1.

[0047] Table 1. Gravity heat pipe unit model parameters

[0048] Using the free tetrahedral meshing method, the solution domain is divided into 268,291 elements, such as... Figure 4 As shown. For each divided unit, the fracture aperture during the heat extraction process can be updated in real time through a dynamic calculation model of fracture aperture. The updated fracture aperture is then coupled to the seepage field and heat transfer field to calculate the distribution of temperature field, seepage field, mechanical field and chemical field in the near-wellbore area during the heat extraction process, as well as the temporal change of heat extraction power of the heat pipe unit.

[0049] Example 2: This embodiment simulates and predicts the heat extraction effect of the heat pipe unit based on the method described in Embodiment 1, and analyzes the influencing factors of the heat extraction effect of the heat pipe unit and predicts the heat transfer enhancement effect of the gravity heat pipe near the well.

[0050] The analysis of factors affecting the heat extraction effect of heat pipe units includes the influence of changes in fissure opening on the heat extraction process, the influence of fissure inclination angle on the heat extraction process, and the influence of fissure opening on the heat extraction process.

[0051] Specifically, regarding the impact of fracture aperture variation on the geothermal extraction process of the heat pipe, the aforementioned model was used to simulate the multi-field coupling process within a single heat pipe unit during geothermal extraction via gravity heat pipes. Taking the gravity heat pipe extraction test of well D34 in Xiong'an New Area as a background, the temperature conditions of a heat pipe section at a depth of 3000 m were selected, with a formation temperature of approximately 110℃ at this depth. The fracture dip angle was set to 40°, the fracture aperture to 1 mm, and the simulation period to 40 days. Figure 5 The calculation results of the model temperature field show that the temperature in the near-well region gradually decreases as the heat pipe extracts heat.

[0052] like Figure 6 The temporal variation of the heat extraction power of the heat pipe section shows that in the early stage of heat pipe heat extraction, the heat extraction power decreased rapidly due to the decrease in the temperature of the rock near the heat pipe wall. Within 2 days, the heat extraction power decreased from more than 15 kW to 8.27 kW. After that, the decreasing trend of heat extraction power slowed down, and after 40 days of heat extraction, the heat extraction power of the heat pipe section was about 5.69 kW.

[0053] During heat extraction via heat pipes, the rock undergoes multi-physics interactions. Simultaneously with temperature changes, the fracture aperture changes under the control of thermodynamics and chemical reactions. On one hand, temperature changes cause rock expansion / contraction under thermal stress; on the other hand, the decrease in temperature disrupts the mineral dissolution and precipitation equilibrium, leading to chemical aperture. The figure below shows that, under the influence of rock contraction and mineral precipitation, the initial fracture aperture of 1 mm increased to approximately 1.35 mm after 40 days of heat extraction.

[0054] like Figure 7 and Figure 8 As shown, an increase in fracture aperture enhances natural convection driven by temperature difference, thus affecting the heat extraction process. Under the multi-field coupled interaction of THMC, changes in fracture aperture significantly affect the predicted heat extraction power. Without considering changes in fracture aperture, the heat extraction power during model operation decreased from 8.28 kW on day 1 to 4.60 kW on day 40; while considering changes in fracture aperture, the heat extraction power decreased from 9.27 kW on day 1 to 5.69 kW on day 40. The relative errors between the two methods range from 10.72% to 19.16%.

[0055] The influence of fracture dip angle on the heat transfer process is discussed, and the near-wellbore heat transfer process under fracture dip angles of 40°, 60° and 80° is calculated respectively. Figure 9The temperature field variations calculated by different fracture dip angle models are shown. It can be seen that as the fracture dip angle increases, the natural convection enhancement effect caused by the temperature difference in the reservoir becomes increasingly significant. Under the condition of an 80° fracture dip angle, a significant low-temperature region appears in the fracture surface temperature field after 40 days of heat extraction, indicating that more heat is carried away through the heat pipe heat exchange process. Long-term stable heat extraction power analysis shows that, under the same fracture aperture (1 mm), the heat extraction power at a 40° dip angle drops to approximately 5.72 kW on day 40, while the heat extraction power at an 80° dip angle is approximately 6.78 kW during the same period. The difference is 1.06 kW, approximately 20% of the heat extraction power under the 40° dip angle condition.

[0056] To investigate the impact of fracture aperture on the heat pipe extraction process, the near-wellbore heat transfer process under different fracture aperture conditions was further simulated, with the fracture inclination angle fixed at 40°. For example... Figure 11 The results show that increasing the slit opening can significantly accelerate the natural convection process caused by the temperature difference, thereby enhancing the heat extraction effect of the heat pipe.

[0057] like Figure 12 The heat extraction power variation curves under different fissure opening conditions show that when the fissure opening increases from 0.5 mm to 1 mm, the stable heat extraction power of the heat pipe section (on day 40) increases from 3.40 kW to 5.72 kW, an increase of approximately 68.24%. When the fissure opening further increases to 2 mm, the heat extraction power on day 40 reaches 19.84 kW, which is approximately 5.83 times that under the 0.5 mm opening condition.

[0058] This embodiment further predicts the heat transfer enhancement effect of gravity heat pipes in the near-wellbore area. In geothermal systems, the heat extraction process of ultra-long gravity heat pipes does not involve direct convective heat exchange with reservoir fluids; instead, it obtains heat from the formation through thermal conduction. During this process, the natural convection process within the reservoir caused by temperature changes within the formation also affects the heat extraction process of the gravity heat pipes. Therefore, both conduction-type and convection-type enhancement schemes are set in the model.

[0059] The conductive reinforcement scheme requires filling the area around the heat pipe with a high thermal conductivity material as a reinforcing material. The variables to be considered in this scheme are the thermal conductivity of the high thermal conductivity material and the filling range of the reinforcing material.

[0060] Convection-type enhancement schemes improve the permeability of near-wellbore reservoirs through artificial fracturing, microwave stimulation, and other means. Variables to consider in this scheme include the permeability after stimulation and the range of permeability enhancement.

[0061] For the prediction of the conductive reinforcement scheme, the model achieves the effect of conductive enhancement by adding a high thermal conductivity material domain in the near-wellbore region of the heat pipe. Existing techniques have evaluated the impact of near-wellbore thermal conductivity enhancement on the heat extraction efficiency of the heat pipe, finding that enhancing the thermal conductivity of the rock within 5m of the heat pipe has a significant effect on the heat extraction effect, while the effect of conductive enhancement outside this range is unclear. Therefore, in this embodiment, the fracture extension length is also controlled within 5m. Considering some common high thermal conductivity materials (silicon carbide has a thermal conductivity of 50-490 W / m·K, graphene can reach 2000 W / m·K, and the thermal conductivity of traditional thermally conductive cement is usually in the range of 2.0~10 W / (m·K)), the thermal conductivity of the high thermal conductivity range is set to 2, 4, 6, 8, 10 W / (m·K) in the model; the reinforcement range is set to 1, 2, 3, 4, 5m.

[0062] First, with a fixed reinforcement radius of 5m, the heat transfer effect under different thermal conductivity conditions of the reinforcement materials is discussed. For example... Figure 13 Calculation results show that the conductive enhancement scheme can effectively enhance the heat extraction power of gravity heat pipes. After 40 days of heat extraction, the heat extraction power (14.98 kW) using the 10 W / m·K enhancement material scheme is approximately 2.33 times that of the 2 W / m·K enhancement material scheme (6.43 kW).

[0063] like Figure 14 Calculation results under different enhancement range conditions show that increasing the radius of the enhancement area has a significant impact on the heat extraction power enhancement effect in the early stage of heat extraction; and the impact on heat extraction power is most significant when the enhancement range changes within a small range; when the enhancement range increases from 0m to 2m, the heat extraction power increases from 5.72 kW to 12.07 kW after 40 days; when the radius of the enhancement range increases to 3m, the enhancement effect on heat extraction power begins to decrease, and the heat extraction power after 40 days is about 14.98 kW under the condition of enhancement range of 5m.

[0064] Predicted results of the convection-based enhancement scheme: Using the convection-based enhancement scheme, the permeability of the reservoir within a certain range near the wellbore (the enhancement range is defined as a cylindrical area with a radius of 5m) is set to 5e-13, 1e-12, 5e-12, and 1e-11 m, respectively. 2 .like Figure 15 Calculations show that when the permeability increases to 5×10 -12 m 2 Subsequently, it has a significant impact on thermal power. When the permeability increases to 1×10 -11 m 2 After 40 days, the heat extraction power increased from 5.72 kW to 7.08 kW.

[0065] like Figure 16Calculation results under different enhancement ranges show that increasing the permeability of the near-wellbore thermal reservoir can slow down the decline in heat pipe extraction power and improve the long-term heat extraction power of gravity heat pipes. For every 1m increase in the enhancement radius, the heat extraction power increases by approximately 0.27 kW after 40 days.

[0066] Comparing the prediction results of conduction-based and convection-based enhancement schemes, it can be found that the conduction-based enhancement scheme improves heat transfer throughout the entire heat extraction cycle, meaning it increases the overall heat extraction power from the start to the end of the heat extraction test. In contrast, the heat extraction power remains essentially the same at the beginning under different enhancement conditions in the convection-conduction enhancement scheme; the increased permeability mitigates the decay of heat extraction power by enhancing natural convection within the reservoir. In practical heat extraction projects, the enhancement scheme should be rationally selected based on reservoir geological conditions and temperature characteristics.

[0067] Based on the above-described effect tests of the method proposed in Example 1, it can be concluded that the method of this application considers the dynamic change process of fracture aperture under the influence of temperature and its impact on the heat extraction effect of the heat pipe. Furthermore, the effects of two near-wellbore heat transfer enhancement schemes, namely conductive and convective types, are discussed. Therefore, the advancement of the method of this application is reflected in: (1) Under the multi-field coupling interaction of THMC, the change in fracture aperture significantly affects the predicted results of thermal power. Without considering the change in fracture aperture, the thermal power during the model operation decreased from 8.28 kW on day 1 to 4.60 kW on day 40; while considering the change in fracture aperture, the thermal power decreased from 9.27 kW on day 1 to 5.69 kW on day 40. The relative error between the two is 10.72~19.16%.

[0068] (2) Both the dip angle and the opening of the fissure have a significant impact on the heat extraction effect. A larger fissure dip angle and opening enhance the natural convection driven by the temperature difference, thereby increasing the heat extraction power. When the fissure opening is 1 mm, the heat extraction power on the 40th day under the 80° dip angle condition (6.78 kW) is about 20% higher than that under the 40° dip angle condition (5.72 kW). When the fissure opening increases from 0.5 mm to 2.0 mm, the heat extraction power on the 40th day increases significantly from 3.40 kW to 19.84 kW, an increase of 5.83 times.

[0069] (3) The conduction-type enhancement scheme increases the overall thermal power throughout the entire heating cycle by improving the thermal conductivity in the near-wellbore area. Using a high thermal conductivity material of 10 W / (m·K), the thermal power on day 40 (14.98 kW) is approximately 2.33 times that of the scheme using 2 W / (m·K) material (6.43 kW). The convection-type enhancement scheme, on the other hand, enhances natural convection by increasing permeability. Its main function is to slow down the decay of thermal power, with a relatively small impact on the initial thermal power. When the permeability increases to 1×10...-11 m 2 At that time, the heating power increased from 5.72 kW to 7.08 kW on the 40th day.

[0070] Example 3: Another aspect of this application provides a near-wellbore heat transfer coupling simulation system for gravity heat pipe heat harvesting, such as... Figure 17 The diagram shown is a structural diagram of a gravity heat pipe near-wellbore heat transfer coupling simulation system provided in an embodiment of this application. The gravity heat pipe near-wellbore heat transfer coupling simulation system includes: The heat pipe unit creation module 1701 is configured to generalize an ultra-long gravity heat pipe into multiple independent heat pipe segments, and to construct a gravity heat pipe unit model for a single heat pipe segment and the surrounding rock near the wellbore within a predetermined radial range. The coupling calculation module 1702 is configured to construct a THMC multi-field coupling model that includes multiple physical fields, couple the interactions of each physical field, and establish a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field; The condition setting module 1703 is configured to set the initial or boundary conditions of the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model according to the actual geological parameters and heat recovery conditions of the target reservoir. The model solving module 1704 is configured to mesh the gravity heat pipe unit model, solve the THMC multi-field coupling model based on the initial conditions and boundary conditions, and update the fracture opening in real time during the heat extraction process through the fracture opening dynamic calculation model to obtain the multi-physics field distribution and time-series change of heat extraction power in the near-wellbore area during the heat extraction process.

[0071] It should be noted that the gravity heat pipe heat recovery near-wellbore heat transfer coupling simulation device provided in the above embodiments and the gravity heat pipe heat recovery near-wellbore heat transfer coupling simulation method provided in the aforementioned embodiments belong to the same concept. The specific operation methods of each module and unit have been described in detail in the method embodiments, and will not be repeated here.

[0072] Another aspect of this application provides an electronic device, including: a controller; and a memory for storing one or more programs, which, when executed by the controller, perform the methods described in the various embodiments above.

[0073] Another aspect of this application provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method as described above. This computer-readable storage medium may be included in the electronic device described in the above embodiments, or it may exist independently and not assembled into the electronic device.

[0074] Another aspect of this application provides a computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the methods provided in the various embodiments described above.

[0075] According to one aspect of the embodiments of this application, a computer system is also provided, including a central processing unit (CPU), which can perform various appropriate actions and processes based on a program stored in read-only memory (ROM) or a program loaded from storage into random access memory (RAM), such as performing the methods described above. Various programs and data required for system operation are also stored in the RAM. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0076] For example, a computer system includes a Central Processing Unit (CPU), which can perform various appropriate actions and processes based on a program stored in read-only memory (ROM) or loaded from storage into random access memory (RAM), such as executing the methods described in the above embodiments. The RAM also stores various programs and data required for system operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0077] The following components are connected to the I / O interface: input sections including keyboards, mice, etc.; output sections including cathode ray tubes (CRTs), liquid crystal displays (LCDs), and speakers; storage sections including hard drives; and communication sections including network interface cards such as LAN (Local Area Network) cards and modems. The communication sections perform communication processing via networks such as the Internet. Drives are also connected to the I / O interface as needed. Removable media, such as disks, optical discs, magneto-optical discs, semiconductor memories, etc., are installed on the drive as needed so that computer programs read from them can be installed into the storage section as required.

[0078] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including a computer program for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), it performs various functions defined in the system of this application.

[0079] It should be noted that the computer-readable medium shown in the embodiments of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying a computer-readable computer program. The transmitted data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0080] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0081] The module units described in the embodiments of this application can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0082] The above embodiments are only used to illustrate this application and are not intended to limit this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application. Therefore, all equivalent technical solutions also fall within the scope of this application, and the patent protection scope of this application should be defined by the claims.

Claims

1. A method for simulating near-wellbore heat transfer performance considering THMC coupling, characterized in that, The method includes: The ultra-long gravity heat pipe is generalized into multiple independent heat pipe segments, and a gravity heat pipe unit model is constructed for each heat pipe segment and the surrounding rock near the well within a predetermined radial range. A multi-field coupled THMC model including multiple physical fields is constructed, considering the coupling effect between the physical fields, and a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture is established; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field; Based on the actual geological parameters and heat recovery conditions of the target reservoir, the initial or boundary conditions of the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model are set respectively. The gravity heat pipe unit model is meshed, and the THMC multi-field coupling model is solved based on the initial and boundary conditions. The fracture opening is updated in real time during the heat extraction process through the fracture opening dynamic calculation model, so as to obtain the multi-physics field distribution and time-series change of heat extraction power in the near-wellbore area during the heat extraction process.

2. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to claim 1, characterized in that, In the seepage field of the THMC multi-field coupling model, the seepage process in the matrix is ​​represented as follows: in, For fluid density; Reservoir porosity; For time; The fluid velocity; For gradient operators; fluid velocity The calculation formula is: in, Reservoir permeability; The fluid dynamic viscosity coefficient; For fluid pressure; It is a gravity term; For fluid density; It is the acceleration due to gravity; z Vertical depth; The mass conservation equation for the fluid in the fracture is as follows: in, The crack opening; For fluid density; The fluid velocity in the crack; For time; The porosity is the fracture porosity. The gradient operator for the tangential plane of the crack; The mass flow rate through the crack; In the temperature field within the reservoir, the heat balance within the reservoir can be expressed as: in, and These are the equivalent heat capacity and equivalent thermal conductivity; Rock temperature; For time; For gradient operators; Represents the heat convection term. Represents the heat conduction term; For the heat transferred; Equivalent heat capacity and equivalent thermal conductivity are defined as follows: in, and Density of solids and fluids; and For the heat capacity of solids and fluids (J / (kg·K)); and It is the thermal conductivity of solids and fluids. In a mechanical field, a linear elastic model is used to describe the elastic deformation of the fracture surface: in, Effective stress; and These are the tangential and normal stresses; and Stiffness in the tangential and normal directions; and For tangential and normal displacements; In a chemical field, the transport process of dilute substances is described by the following convection-dispersion equation: in, The concentration of the solute in the fluid; The fluid diffusion coefficient; This represents the fluid velocity.

3. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to claim 2, characterized in that, Considering the coupling effects between various physical fields, the influence of temperature changes on fluid properties can be described as follows: in, The density of water is affected by temperature; The viscosity of water is affected by temperature; The thermal conductivity of water under the influence of temperature; The heat capacity of water under the influence of temperature.

4. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to claim 2, characterized in that, Considering the coupling effect between various physical fields, the change in crack aperture caused by the mechanical field is expressed as: in, The change in crack aperture caused by the mechanical field; The stress is in the normal direction; Stiffness in the normal direction; f This refers to fluid pressure.

5. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to claim 2, characterized in that, Considering the coupling effects between various physical fields, the crack aperture caused by chemical dissolution or precipitation. Determined by the following formula: in, Density of solid; This indicates the number of moles of silica per unit mass of rock. The reaction rate is determined by the following formula: in, The reaction rate; The reaction rate constant; To balance the concentration; This refers to the density of the solute. The equilibrium concentration is determined by the following formula: in, The temperature of the rock.

6. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to any one of claims 1 to 5, characterized in that, The dynamic calculation model for the fracture aperture is expressed as follows: in, The initial aperture of the fracture. The change in crack aperture caused by the mechanical field. The crack opening caused by chemical dissolution or precipitation.

7. The near-wellbore heat transfer coupling simulation method for gravity heat pipe heat recovery according to claim 1, characterized in that, Based on the actual geological parameters and thermal recovery conditions of the target reservoir, initial or boundary conditions are set for the temperature field, seepage field, mechanical field, and chemical field within the reservoir in the gravity heat pipe unit model, including: The initial conditions of the temperature field are set according to the measured temperature at the current depth of the reservoir. The boundary conditions of the temperature field are: the periphery of the gravity heat pipe unit model is set as a constant temperature boundary, and the heat pipe is set as the boiling point temperature of the circulating working fluid. The boundary condition for the seepage field is: the periphery of the gravity heat pipe unit model is set as a flow-free boundary; The boundary conditions of the mechanical field are: the four sides of the gravity heat pipe unit model are set as fixed constraints; The initial conditions of the chemical field are set as follows: the dissolution-precipitation equilibrium state at the current temperature.

8. A near-wellbore heat transfer performance simulation system considering THMC coupling, characterized in that, The system includes: The heat pipe unit creation module is configured to generalize ultra-long gravity heat pipes into multiple independent heat pipe segments, and to construct gravity heat pipe unit models for a single heat pipe segment and the surrounding rock near the well within a predetermined radial range. The coupling calculation module is configured to construct a THMC multi-field coupling model that includes multiple physical fields, consider the coupling effect between the physical fields, and establish a dynamic calculation model for fracture aperture that simultaneously considers mechanical aperture and chemical aperture; the multiple physical fields include the reservoir temperature field, seepage field, mechanical field and chemical field; The condition setting module is configured to set the initial and boundary conditions of the temperature field, seepage field, mechanical field and chemical field in the gravity heat pipe unit model according to the actual geological parameters and heat recovery conditions of the target reservoir. The model solving module is configured to mesh the gravity heat pipe unit model, solve the THMC multi-field coupling model based on the initial and boundary conditions, and update the fracture opening in real time during the heat extraction process through the fracture opening dynamic calculation model to obtain the multi-physics field distribution and time-series changes of heat extraction power in the near-wellbore area.

9. An electronic device, characterized in that, The electronic device includes: Memory, used to store computer programs; A processor for executing the computer program to implement the method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing instructions, characterized in that, When the instructions are executed by the processor, the method according to any one of claims 1 to 7 is performed.

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