Method and device for predicting underground heat exchange effect of geothermal well transformed from idle well and storage medium

Abstract

The invention relates to an underground heat exchange effect prediction method and device for transforming an idle well into a geothermal well and a storage medium. The method comprises the steps that shaft data and reservoir data are obtained; establishing a shaft-reservoir coupling dynamic heat transfer model according to the shaft data and the reservoir data; acquiring simulation parameters; and outputting a prediction result according to the shaft-reservoir coupling dynamic heat transfer model and the simulation parameters. According to the underground heat exchange effect prediction method and device for transforming the idle well into the geothermal well and the storage medium, the heat exchange effect after transformation can be integrally evaluated according to the geological conditions and the underground heat exchange parameters before the project of transforming the idle well into the geothermal well on site is implemented, so that a theoretical basis and a data support are provided for the development of actual engineering.

Description

Technical Field

[0001] The present application relates to the field of oil production engineering, and particularly to a method, device, and storage medium for predicting the downhole heat exchange effect of a geothermal well reconstructed from an idle well. Background Art

[0002] At present, there are a large number of old wells in Huabei Oilfield. The downhole heat exchange process has the advantage of heat extraction without water extraction, does not involve the problems of groundwater recharge and treatment, and can realize the effective utilization of idle assets, so it has received extensive attention and research. However, in the field application of this technology, affected by factors such as geological environment, wellbore, and fluid, there are significant differences in the heat exchange effect. There is still a lack of scientific and effective technical support for the evaluation, design, and prediction of geothermal wells reconstructed from old wells, which is not conducive to large-scale popularization and application, and cannot fully tap the potential of geothermal resources. Therefore, improvement is needed. Summary of the Invention

[0003] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides a method, device, and storage medium for predicting the downhole heat exchange effect of a geothermal well reconstructed from an idle well.

[0004] In a first aspect, the present application provides a method for predicting the downhole heat exchange effect of a geothermal well reconstructed from an idle well, the method comprising the steps of:

[0005] Obtain wellbore data and reservoir data;

[0006] Establish a wellbore-reservoir coupled dynamic heat transfer model based on the wellbore data and the reservoir data;

[0007] Obtain simulation parameters;

[0008] Output a prediction result based on the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters.

[0009] Preferably, the obtaining of the wellbore data and the reservoir data comprises the steps of:

[0010] Obtain the wellbore parameters of the reconstructed well;

[0011] Obtain the simulated reservoir parameters;

[0012] Obtain the downhole heat exchange string parameters.

[0013] Preferably, the establishing of the wellbore-reservoir coupled dynamic heat transfer model based on the wellbore data and the reservoir data comprises the steps of:

[0014] Construct a mass conservation equation for the downhole heat exchange effect of a single well;

[0015] Construct a momentum conservation equation for the downhole heat exchange effect of a single well;

[0016] Construct an energy conservation equation for the downhole heat exchange effect of a single well;

[0017] According to each equation, a wellbore-reservoir coupled dynamic heat transfer model is constructed using the local thermal equilibrium theory.

[0018] Preferably, the expression of the mass conservation equation is:

[0019]

[0020] where Ac represents the cross-sectional area of the pipe, ρ f represents the fluid density, t represents time, and u f represents the flow velocity in the pipe.

[0021] Preferably, the expression of the momentum conservation equation is:

[0022]

[0023] where ρ f represents the fluid density, t represents time, u f represents the flow velocity in the pipe, f D represents the Darcy friction factor, dp represents the hydraulic diameter, and p represents the pressure along the pipe.

[0024] Preferably, the expression of the energy conservation equation is:

[0025]

[0026] where ρ f represents the fluid density, A c represents the cross-sectional area of the pipe, c f represents the fluid heat capacity, T f1 represents the fluid temperature inside the inner pipe, t represents time, u f represents the flow velocity in the pipe, λ f represents the fluid thermal conductivity, f D represents the Darcy friction factor, dp represents the hydraulic diameter, and Q 1 represents the heat transfer amount between the fluid in the annulus and the middle inner pipe.

[0027] Preferably, the prediction results output according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters include:

[0028] Predicting the optimal operating parameters of the downhole heat exchange system;

[0029] Predicting the output power and heat transfer amount of the downhole heat exchange system;

[0030] Predicting the energy consumption and economic evaluation data of the downhole heat exchange system.

[0031] In a second aspect, the present application provides a prediction device for the downhole heat exchange effect of a geothermal well after transforming an idle well, including:

[0032] A data acquisition module for acquiring wellbore data and reservoir data;

[0033] A model establishment module for establishing a wellbore-reservoir coupled dynamic heat transfer model based on the wellbore data and the reservoir data;

[0034] A parameter acquisition module for acquiring simulation parameters;

[0035] A result output module for outputting a prediction result based on the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters.

[0036] In a third aspect, an air conditioner control device is provided, including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus;

[0037] The memory is used for storing computer programs;

[0038] The processor, when executing the program stored on the memory, implements the steps of the method for predicting the downhole heat exchange effect of a geothermal well after idle well transformation according to any one of the embodiments in the first aspect.

[0039] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for predicting the downhole heat exchange effect of a geothermal well after idle well transformation according to any one of the embodiments in the first aspect are implemented.

[0040] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0041] A method, device, and storage medium for predicting the downhole heat exchange effect of a geothermal well after idle well transformation provided by the present application can help evaluate the overall heat exchange effect after transformation according to geological conditions and downhole heat exchange parameters before the implementation of the geothermal well project for idle well transformation on site, so as to provide a theoretical basis and data support for the development of actual projects. Description of the Drawings

[0042] The drawings here are incorporated into the description and form a part of this description, showing the embodiments consistent with the present invention, and are used together with the description to explain the principles of the present invention.

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0044] Figure 1It is a schematic flowchart of a method for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well provided by an embodiment of the present invention;

[0045] Figure 2 It is a schematic structural diagram of a device for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well provided by an embodiment of the present invention;

[0046] Figure 3 It is a schematic structural diagram of an electronic device provided by the present invention;

[0047] Figure 4 It is a schematic structural diagram of a non-transitory computer-readable storage medium provided by the present invention;

[0048] Figure 5 It is a schematic diagram of a finite difference discretization grid in a method for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well provided by an embodiment of the present invention;

[0049] Figure 6 It is a numerical calculation flowchart in a method for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well provided by an embodiment of the present invention. Detailed implementation manners

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0051] Figure 1 It is a schematic flowchart of a method for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well provided by an embodiment of the present application.

[0052] The present application provides a method for predicting the downhole heat exchange effect of a geothermal well after transforming an idle well, and the method includes the steps of:

[0053] S1: Obtain wellbore data and reservoir data;

[0054] In the embodiment of the present application, the obtaining of the wellbore data and the reservoir data includes the steps of:

[0055] Obtain the wellbore parameters of the reformed well;

[0056] Obtain the simulated reservoir parameters;

[0057] Obtain the downhole heat exchange string parameters.

[0058] Specifically, the wellbore data includes: the wellbore parameters of the reformed well and the downhole heat exchange string parameters, and the reservoir data includes the simulated geothermal reservoir parameters.

[0059] S2: Establish a wellbore-reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data;

[0060] In the embodiment of the present application, the establishment of the wellbore-reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data includes the steps of:

[0061] Construct the mass conservation equation of the downhole heat exchange effect of a single well;

[0062] Construct the momentum conservation equation of the downhole heat exchange effect of a single well;

[0063] Construct the energy conservation equation of the downhole heat exchange effect of a single well;

[0064] Construct a wellbore-reservoir coupled dynamic heat transfer model according to each equation by using the local thermal equilibrium theory.

[0065] Specifically, the prediction model is constructed based on the heat extraction principle using the local thermal equilibrium theory. According to the mathematical equations of mass conservation, momentum conservation and energy conservation, a wellbore-reservoir coupled dynamic heat transfer model is established. The downhole heat exchange effect of a single well is simulated. The model forms a double-tube coaxial casing space by the original oil well casing and the central tube. The low-temperature circulating medium is injected into the upper casing annulus, and after completing the downhole heat exchange with the casing wall along the way, it flows out through the central tube. The central tube string is divided into two parts: a heat conduction section and a heat insulation section. The upper heat insulation section of the inner tube is made of heat-insulating fiber-reinforced polyethylene material, and the lower part is designed with heat-conducting material.

[0066] In the embodiment of the present application, the expression of the mass conservation equation is:

[0067]

[0068] Among them, A c represents the cross-sectional area of the pipeline, ρ f represents the fluid density, t represents time, and u f represents the flow velocity in the pipeline.

[0069] In the embodiment of the present application, the expression of the momentum conservation equation is:

[0070]

[0071] Among them, ρ f represents the fluid density, t represents time, u f represents the flow velocity in the pipeline, f D represents the Darcy friction factor, dp represents the hydraulic diameter, and p represents the pressure along the pipeline.

[0072] In the embodiment of the present application, the expression of the energy conservation equation is:

[0073]

[0074] where ρ f represents the fluid density, Ac represents the cross-sectional area of the pipeline, c f represents the fluid heat capacity, T f1 represents the temperature of the fluid inside the inner pipe, t represents time, u f represents the flow velocity in the pipeline, λ f represents the fluid thermal conductivity, f D represents the Darcy friction factor, d p represents the hydraulic diameter, Q 1 represents the heat exchange amount between the fluid in the annulus and the middle inner pipe.

[0075] S3: Obtain simulation parameters;

[0076] In the embodiment of the present application, the obtaining of the simulation parameters includes the steps of:

[0077] Obtain the geological environment;

[0078] Obtain the wellbore environmental conditions.

[0079] Specifically, the simulation parameters include: the geological environment and the wellbore environmental conditions.

[0080] S4: Output a prediction result according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters.

[0081] In the embodiment of the present application, outputting a prediction result according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters includes:

[0082] Predict the optimal operating parameters of the downhole heat exchange system;

[0083] Predict the output power and heat exchange amount of the downhole heat exchange system;

[0084] Predict the energy consumption and economic evaluation data of the downhole heat exchange system.

[0085] Specifically, through structured grid division, the influence of different geological environments and wellbore conditions on the heat exchange effect is simulated, the outlet water temperature of the downhole heat exchange, the evolution of the reservoir temperature field, etc. are predicted, and the downhole heat exchange effect of the actual scenario or field test is predicted and fitted, and the model prediction accuracy reaches more than 85%.

[0086] The specific steps of a method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well provided by this application are as follows: It is constructed based on its heat extraction principle. For the heat exchange processes in the formation, cement sheath, and casing, it is a heat transfer process without mass transfer. The model adopts the local thermal equilibrium theory, that is, it is considered that there is no temperature difference between the rock and fluid in the reservoir. Water is selected as the working fluid, and due to the relatively small influence of phase change, only its single-phase flow is considered. The properties of water change with temperature, and the relevant calculation formulas are as follows:

[0087]

[0088] Among them, ρ f (kg / m 3 ) represents the fluid density, T c (℃) represents Celsius temperature, and T(K) represents Kelvin temperature.

[0089]

[0090] Among them, μ f (Pa·s) represents the fluid viscosity.

[0091] The heat extraction process in the well is described using a non-isothermal pipe flow model, where the mass conservation and momentum equations can be expressed as:

[0092]

[0093]

[0094] Among them, A c (m 2 ) represents the cross-sectional area of the pipe. u f (m / s) represents the flow velocity in the pipe. p(Pa) represents the pressure along the pipe. d p (m) represents the hydraulic diameter. It should be particularly noted that the second term on the right side of expression (4) represents the pressure loss caused by viscous friction. Among them, the parameter fD is the Darcy friction factor, which can be calculated by the following formula:

[0095]

[0096]

[0097]

[0098] Among them, Re represents the Reynolds number. e(m) represents the surface roughness of the pipe. According to the inner pipe heat exchange process, the energy equation can be:

[0099]

[0100] Based on the established mathematical model, the discrete equations of the mathematical model are established using the finite difference method. The convective heat transfer coefficient and Darcy friction factor are updated based on fluid properties, etc., and parameters such as temperature, pressure, velocity, and physical properties under different conditions are calculated.

[0101] In Equation (8), T f1 (K) represents the temperature of the fluid inside the inner pipe. c f (J / (kg·K)) represents the specific heat capacity of the fluid. The second and third terms on the left side of Equation (8) correspond to heat convection and heat conduction, respectively. The first term on the right side of Equation (8) characterizes the viscous friction between the fluid and the wellbore wall. Q 1 (W) is the heat source term, representing the heat exchange between the fluid in the annulus and the inner and middle pipes. Its calculation formula is:

[0102]

[0103] Among them, T f2 (K) represents the temperature of the fluid in the annulus. The parameter R 1 ((m·K) / W) is the thermal resistance describing the heat transfer of the inner pipe and is calculated by the following formula:

[0104]

[0105] Among them, r (m) represents the radius. λ m (W / (m·K)) is the thermal conductivity of the inner pipe. The variables h 1 and h 2 (W / m 2 ·K) represent the convective heat transfer coefficients in the inner pipe and the annulus, respectively, and are related to fluid properties and flow velocity, etc. Their calculation formulas are as follows:

[0106]

[0107] Among them, Nu is the Nusselt number, representing the convective heat transfer intensity between the fluid and the wellbore wall, and can be determined by the Gnielinski equation:

[0108]

[0109] Among them, Pr is the Prandtl number. Considering the dynamic heat transfer process in the coaxial heat exchange well annulus, the heat transfer equation can be:

[0110] (13)

[0112] Among them, Q 2 (W) represents the heat exchange between the fluid in the annulus and the surrounding formation, and its calculation formula can be expressed as:

[0113]

[0114] Among them, T s (K) represents the formation temperature around the well. R ((m·K) / W) represents the thermal resistance, and its expression is:

[0115]

[0116] Among them, λ w and λ c (W / (m·K)) represent the thermal conductivities of the casing and the cement sheath respectively. In addition, the formation energy equation is:

[0117]

[0118] Among them, (ρc) eff and λ eff represent the effective volume heat capacity and the thermal conductivity of the formation respectively, and are determined by the volume averaging method:

[0119]

[0120]

[0121] Among them, φ represents the formation porosity. ρ s (kg / m 3 ), c s (J / (kg·K)) and λ s (W / (m·K)) represent the density, heat capacity and thermal conductivity of the rock in the formation respectively. In addition, the heat extraction power is calculated by the following equation to evaluate the heat generation rate:

[0122] P = 10 -6 ·(q out ρ f,out c f,out T out - q in ρ f,in c f,in T in ) (19)

[0123] Among them, P (MW) represents the heat extraction power. q (m 3 / s) is the volume flow rate. The subscripts in and out represent the parameters at the inlet and outlet respectively.

[0124] Such as Figure 5The discrete grid of the partitioned finite difference method is shown, and each grid cell is numbered in the axial and radial directions. According to the symmetry of the simulation calculation domain, the fluid domain, casing, and cement sheath are represented by one-dimensional elements, while a two-dimensional grid is introduced to characterize the surrounding formation. Considering numerical stability, the fully implicit finite difference method is used to discretize the energy conservation equation of cylinder heat transfer at each grid node. All nodes are assumed to be at the current time node, and only the temperature at the previous time step in the time partial derivative is set as known. Finally, the partial differential equation is transformed into a difference equation for solution. Finally, by combining like terms and transposing, the heat transfer coefficient matrix is formed.

[0125] Taking the heat transfer equation as an example, its discrete form will be shown below. The discrete equation for heat transfer of the inner tube fluid is:

[0126]

[0127] Where A 1 = -B 1 -C 1 +D 1 ,

[0128]

[0129] The discrete equation for heat transfer of the fluid in the annulus is:

[0130]

[0131] Where A 2 = -B 2 -C 2 -D 2 +E 2 ,

[0132] D 2 = 2r 5 h 3 ,

[0133] The discrete equation for heat transfer of the casing is:

[0134]

[0135] Where A 3 = -B 3 -C 3 -D 3 -E 3 +F 3 , D 3 = 2r 5 h 3 ,

[0136] The discrete equation for heat transfer in the cement sheath is:

[0137]

[0138] Where A 4 =-B 4 -C 4 -D 4 -E 4 +F 4 ,

[0139]

[0140] The discrete equation for heat transfer in the formation is:

[0141]

[0142] Where A i =-B i -C i -D i -E i +F i ,

[0143]

[0144]

[0145]

[0146] As Figure 6 shown is the solution process of the Gauss-Seidel iteration method for the heat transfer coefficient matrix model. The specific steps are as follows:

[0147] (1) Based on the constructed mathematical model, apply temperature and pressure to the boundary, initialize each physical field, and set the simulation time and convergence residual.

[0148] (2) Discretely solve the mathematical model, judge the convergence according to the residual condition, and update the fluid physical properties based on the converged temperature and pressure.

[0149] (3) Update the convective heat transfer coefficient and Darcy friction factor based on the fluid physical properties, etc., output the temperature, pressure, velocity, and physical properties and other parameters at this time step, calculate the temperature error error. If it is less than the set error, jump out of the loop, and the calculation at this moment ends. If not, update the temperature and repeat steps 2 and 3, and output the temperature, pressure, velocity, and physical properties and other parameters of all nodes at this moment.

[0150] Subsequently, repeat steps 2 - 3 to perform numerical iterative calculations for the next time step until the set simulation time is reached.

[0151] The formula for the Gauss - Seidel iteration method is as follows:

[0152]

[0153] In the formula, a represents any one of ABCDE.

[0154] As Figure 2 , this application provides a prediction device for the down - hole heat exchange effect of a geothermal well reconstructed from an idle well, including:

[0155] A data acquisition module 10, configured to acquire wellbore data and reservoir data;

[0156] A model establishment module 20, configured to establish a wellbore - reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data;

[0157] A parameter acquisition module 30, configured to acquire simulation parameters;

[0158] A result output module 40, configured to output a prediction result according to the wellbore - reservoir coupled dynamic heat transfer model and the simulation parameters.

[0159] The prediction device for the down - hole heat exchange effect of a geothermal well reconstructed from an idle well provided by this application can execute the prediction method for the down - hole heat exchange effect of a geothermal well reconstructed from an idle well provided in the above steps.

[0160] It should be understood that the above - mentioned specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modification examples falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

[0161] Next, refer to Figure 3 , which shows a schematic structural diagram of an electronic device 100 suitable for implementing the embodiments of the present disclosure. The electronic device in the embodiments of the present disclosure may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), PMPs (Portable Multimedia Players), vehicle terminals (such as vehicle navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 3 The shown electronic device is only an example and should not bring any limitation to the functions and usage scope of the embodiments of the present disclosure.

[0162] As shown Figure 3 in the figure, the electronic device 100 may include a processing device (such as a central processing unit, a graphics processing unit, etc.) 101, which may perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 102 or the program loaded from the storage device 108 into the random access memory (RAM) 103. In the RAM 103, various programs and data required for the operation of the electronic device 100 are also stored. The processing device 101, the ROM 102, and the RAM 103 are connected to each other through a bus 104. The input / output (I / O) interface 105 is also connected to the bus 104.

[0163] Generally, the following devices may be connected to the I / O interface 105: an input device 106 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 107 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 108 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 109. The communication device 109 may allow the electronic device 100 to communicate with other devices wirelessly or wiredly to exchange data. Although the figure shows the electronic device 100 having various devices, it should be understood that it is not required to implement or have all the shown devices. More or fewer devices may be implemented or had alternatively.

[0164] Specifically, according to an embodiment of the present disclosure, the process described above with reference to the flowchart may be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes program codes for performing the method shown in the flowchart. In such an embodiment, the computer program may be downloaded and installed from the network through the communication device 109, or installed from the storage device 108, or installed from the ROM 102. When the computer program is executed by the processing device 101, the above functions defined in the method of the embodiment of the present disclosure are executed.

[0165] Next, refer to Figure 4 , which shows a schematic structural diagram of a computer-readable storage medium suitable for implementing the embodiment of the present disclosure. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it can implement the prediction method for the heat exchange effect in the geothermal well after the transformation of the idle well as described in any one of the above.

[0166] A method, device, and storage medium for predicting the heat exchange effect in the geothermal well after the transformation of the idle well provided by the present application can help to comprehensively evaluate the heat exchange effect after the transformation according to the geological conditions and downhole heat exchange parameters before the implementation of the geothermal well project for the transformation of the idle well on site, so as to provide a theoretical basis and data support for the development of the actual project.

[0167] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0168] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well, characterized in that, the method comprises the steps of: obtaining wellbore data and reservoir data; establishing a wellbore-reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data; obtaining simulation parameters; outputting a prediction result according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters.

2. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 1, characterized in that, the obtaining of the wellbore data and the reservoir data comprises the steps of: obtaining the wellbore parameters of the reformed well; obtaining the simulated reservoir parameters; obtaining the parameters of the downhole heat exchange pipe string.

3. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 1, characterized in that, the establishing of the wellbore-reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data comprises the steps of: constructing a mass conservation equation for the downhole heat exchange effect of a single well; constructing a momentum conservation equation for the downhole heat exchange effect of a single well; constructing an energy conservation equation for the downhole heat exchange effect of a single well; establishing a wellbore-reservoir coupled dynamic heat transfer model according to each equation by using the local thermal equilibrium theory.

4. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 3, characterized in that, the expression of the mass conservation equation is: Among them, A c represents the cross-sectional area of the pipeline, ρ f represents the fluid density, t represents time, and u f represents the flow velocity in the pipeline.

5. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 3, characterized in that, the expression of the momentum conservation equation is: where ρ f represents the fluid density, t represents time, u f represents the flow velocity in the pipeline, f D represents the Darcy friction factor, dp represents the hydraulic diameter, and p represents the pressure along the pipeline.

6. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 3, characterized in that, the expression of the energy conservation equation is: Among them, ρ f represents the fluid density, Ac represents the cross-sectional area of the pipe, c f represents the fluid heat capacity, T f1 represents the fluid temperature inside the inner pipe, t represents time, u f represents the flow velocity in the pipe, λ f represents the fluid thermal conductivity, f D represents the Darcy friction factor, d p represents the hydraulic diameter, Q 1 represents the heat transfer quantity between the fluid in the annulus and the middle inner pipe.

7. The method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to claim 1, characterized in that, the outputting of the prediction result according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters includes: predicting the optimal operation parameters of the downhole heat exchange system; predicting the output power and heat exchange amount of the downhole heat exchange system; predicting the energy consumption and economic evaluation data of the downhole heat exchange system.

8. A device for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well, characterized in that, it includes: a data acquisition module for obtaining wellbore data and reservoir data; a model establishment module for establishing a wellbore-reservoir coupled dynamic heat transfer model according to the wellbore data and the reservoir data; a parameter acquisition module for obtaining simulation parameters; a result output module for outputting a prediction result according to the wellbore-reservoir coupled dynamic heat transfer model and the simulation parameters.

9. An electronic device, characterized in that, it includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; the memory is used for storing a computer program; the processor is used for implementing the steps of the method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to any one of claims 1-7 when executing the program stored on the memory.

10. A computer-readable storage medium, on which a computer program is stored, characterized in that, When the computer program is executed by a processor, it implements the steps of the method for predicting the downhole heat exchange effect of transforming an idle well into a geothermal well according to any one of claims 1-7.

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