Downhole Dynamic Thermal Field Control Method and Device

Abstract

The downhole dynamic thermal field control method and apparatus provided in this application include: acquiring initial temperature field data of the target downhole wellbore and a pre-constructed formation fluid coupling model, and calculating the first total energy supply power of each heating section of the target downhole based on these data; segmenting and heating each heating section of the target downhole according to the first total energy supply power, and acquiring the first real-time temperature data of each heating section of the target downhole; determining the corresponding first downhole thermal field uniformity based on the first real-time temperature data, and determining the thermal field control state based on the uniformity and the first real-time temperature data; if the thermal field control state is a stable and compliant state, maintaining the first total energy supply power of each heating section of the target downhole; if the thermal field control state is a state to be adjusted, adjusting the first total energy supply power to obtain the adjusted second total energy supply power; thereby improving the accuracy of downhole dynamic thermal field control and enhancing the real-time matching capability between energy supply and formation heat demand.

Description

Technical Field

[0001] This application relates to the field of oil and gas development and in-situ exploitation of unconventional oil and gas resources, and in particular to a method and apparatus for downhole dynamic thermal field control. Background Technology

[0002] As oil and gas development extends to deeper and unconventional areas, in downhole operations such as thermal recovery of heavy oil reservoirs and in-situ conversion of oil shale, where the uniformity of the thermal field is extremely important, how to achieve dynamic uniform control of the thermal field through precise energy replenishment has become a core issue for improving recovery rate, reducing development costs, and ensuring operational safety. Therefore, developing a downhole dynamic thermal field control method has become a challenging and significant topic.

[0003] Existing downhole heating methods mainly employ fixed-power heaters or simple segmented heating structures to heat the downhole area in segments using constant or preset power, supplemented by manual periodic temperature measurement and parameter adjustment. Some improved solutions use distributed temperature sensors (DTS) to monitor downhole temperature and perform simple control based on single-point temperature thresholds. Other technologies attempt to use self-limiting materials such as ferromagnetic materials to achieve passive temperature regulation.

[0004] However, existing technologies lack dynamic matching of formation thermal properties and quantitative analysis of heat loss and formation heat storage, resulting in uneven thermal field distribution and low energy utilization. At the same time, relying on manual control or single-point threshold control leads to sluggish response and lacks a quantitative evaluation system, making it impossible to achieve real-time optimization of the overall uniformity of the thermal field. Thus, existing technologies suffer from technical problems such as insufficient dynamic and precise control of downhole thermal fields and lack of real-time matching ability between energy supply and formation thermal demand. Summary of the Invention

[0005] The downhole dynamic thermal field control method and device provided in this application achieve the technical effect of improving the accuracy of downhole dynamic thermal field control and enhancing the ability to match energy supply with formation heat demand in real time.

[0006] In a first aspect, this application provides a method for controlling the dynamic thermal field in a downhole well, comprising:

[0007] Acquire the initial temperature field data of the target wellbore;

[0008] Obtain a pre-constructed formation fluid coupling model;

[0009] Based on the initial temperature field data and the formation fluid coupling model, the total first energy supply power of each heating section in the target well is calculated.

[0010] The target downhole heating section is heated in segments according to the total power of the first energy supply, so as to obtain the first real-time temperature data of each heating section of the target downhole.

[0011] Based on the first real-time temperature data, determine the corresponding first downhole thermal field uniformity;

[0012] Based on the first downhole thermal field uniformity and the first real-time temperature data, the corresponding thermal field control state is determined;

[0013] If the thermal field control state is stable and meets the standard, then maintain the first total energy supply power of each heating section in the target well.

[0014] If the thermal field control state is in an unadjustable state, then the total power of the first energy supply is adjusted to obtain the adjusted total power of the second energy supply.

[0015] Secondly, this application provides a downhole dynamic thermal field control device, comprising:

[0016] The first acquisition module is used to acquire the initial temperature field data of the target downhole wellbore;

[0017] The second acquisition module is used to acquire a pre-constructed formation fluid coupling model;

[0018] The calculation module is used to calculate the total first energy supply power of each heating section in the target well based on the initial temperature field data and the formation fluid coupling model;

[0019] The first processing module is used to perform segmented heating of each heating section of the target well based on the first total energy supply power, so as to obtain the first real-time temperature data of each heating section of the target well.

[0020] The first determining module is used to determine the corresponding first downhole thermal field uniformity based on the first real-time temperature data.

[0021] The second determining module is used to determine the corresponding thermal field control state based on the first downhole thermal field uniformity and the first real-time temperature data.

[0022] The second processing module is used to maintain the total first energy supply power of each heating section in the target well if the thermal field control state is stable and meets the standard.

[0023] The third processing module is used to adjust the total power of the first energy supply if the thermal field control state is in an unadjustable state, so as to obtain the adjusted total power of the second energy supply.

[0024] Thirdly, this application provides a downhole dynamic thermal field control device, including: a memory and a processor;

[0025] The memory stores instructions that the computer executes;

[0026] The processor executes computer execution instructions stored in memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0027] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible embodiments of the first aspect.

[0028] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0029] This application provides a method and apparatus for downhole dynamic thermal field control. It acquires initial temperature field data to provide fundamental data support for thermal field control, improving the accuracy of the initial control basis; acquires a pre-constructed formation fluid coupling model to provide a reliable technical carrier for power calculation, enhancing the rationality of the calculation logic; calculates the total power of the first energy supply to achieve precise preset energy supply, improving the accuracy of initial power configuration; performs segmented heating and acquires the first real-time temperature data to provide real-time basis for judging the thermal field state, improving the flexibility of control response; determines the uniformity of the first downhole thermal field to achieve quantitative judgment of the thermal field state, improving the accuracy of state judgment; determines the thermal field control state to clarify the subsequent control direction, enhancing the pertinence of control decisions; and maintains or adjusts power according to the state, ensuring dynamic adaptation of energy supply, improving the flexibility and accuracy of thermal field control. Overall, it achieves the technical effect of improving the accuracy of downhole dynamic thermal field control and enhancing the real-time matching capability between energy supply and formation heat demand. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] Figure 1 This application provides a schematic diagram of an application data processing system architecture.

[0032] Figure 2 A downhole dynamic thermal field control system is provided as an embodiment of this application;

[0033] Figure 3 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 1 ;

[0034] Figure 4 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 2 ;

[0035] Figure 5 A schematic diagram of a radial profile of wellbore-formation heat exchange provided in an embodiment of this application;

[0036] Figure 6 A graph of radial heat flux density versus radial distance is provided for embodiments of this application;

[0037] Figure 7 A graph showing the relationship between energy supply power and well depth, provided for an embodiment of this application;

[0038] Figure 8 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 3 ;

[0039] Figure 9 A graph showing the thermal field uniformity versus control time provided in the embodiments of this application;

[0040] Figure 10 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 4 ;

[0041] Figure 11 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 5 ;

[0042] Figure 12 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 6 ;

[0043] Figure 13 A temperature versus time graph provided for an embodiment of this application;

[0044] Figure 14 A schematic diagram of the downhole dynamic thermal field control device provided in an embodiment of this application;

[0045] Figure 15 This is a schematic diagram of the structure of the downhole dynamic thermal field control device provided in the embodiments of this application.

[0046] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0048] Due to the limitations of existing technologies in terms of physical constraint embedding methods, it is difficult to dynamically balance the diversity of generation and physical compliance. Furthermore, the lack of a unified multi-scale correlation modeling framework makes it difficult to guarantee the physical consistency of the generated results across different scales. Consequently, there is a technical problem that makes it difficult to achieve physically reasonable and cross-scale collaborative downhole dynamic thermal field control.

[0049] To address the aforementioned issues, this application provides a method and apparatus for downhole dynamic thermal field control. It acquires initial temperature field data to provide fundamental data support for thermal field control, improving the accuracy of the initial control basis; acquires a pre-constructed formation fluid coupling model to provide a reliable technical carrier for power calculation, enhancing the rationality of the calculation logic; calculates the total power of the first energy supply to achieve precise preset energy supply, improving the accuracy of initial power configuration; performs segmented heating and acquires first real-time temperature data to provide real-time basis for judging the thermal field state, improving the flexibility of control response; determines the uniformity of the first downhole thermal field to achieve quantitative judgment of the thermal field state, improving the accuracy of state judgment; determines the thermal field control state to clarify the subsequent control direction, enhancing the pertinence of control decisions; and maintains or adjusts power according to the state, ensuring dynamic adaptation of energy supply, improving the flexibility and accuracy of thermal field control. Overall, it achieves the technical effect of improving the accuracy of downhole dynamic thermal field control and enhancing the real-time matching capability between energy supply and formation heat demand.

[0050] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0051] Figure 1 This is a schematic diagram of an application data processing system architecture provided in an embodiment of this application. The application data processing system is a computer device. Figure 1 As shown, the above architecture includes at least one of a data acquisition device 101, a processing device 102, and a display device 103.

[0052] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the architecture of the application data processing system. In other feasible embodiments of this application, the above architecture may include more or fewer components than illustrated, or combine some components, or split some components, or arrange different components, which can be determined according to the actual application scenario and is not limited here. Figure 1 The components shown can be implemented in hardware, software, or a combination of both.

[0053] In the specific implementation process, the data acquisition device 101 may include an input / output interface or a communication interface, and the data acquisition device 101 can be connected to the processing device through the input / output interface or the communication interface.

[0054] The processing device 102 can accurately calculate the total power of the first energy supply for each heating section and heat it in segments by acquiring the initial temperature field data of the target downhole and the pre-constructed formation fluid coupling model. It can also collect real-time temperature data to determine the uniformity and control status of the thermal field, and maintain or adjust the power according to the status to achieve dynamic and precise control of the downhole thermal field.

[0055] The display device 103 can also be a touch screen or the screen of a terminal device, used to receive user commands while displaying the above-mentioned content, so as to realize interaction with the user.

[0056] It should be understood that the aforementioned processing device can be implemented by a processor reading instructions from memory and executing those instructions, or it can be implemented by a chip circuit.

[0057] Furthermore, the network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0058] Figure 2 A downhole dynamic thermal field control system provided in this application embodiment, such as Figure 2 As shown, the downhole dynamic thermal field control system 200 provided in this embodiment includes a surface intelligent control unit 201, a power supply device 202, a data acquisition center 203, a downhole segmented heater group 204, and distributed temperature sensors 205.

[0059] The ground intelligent control unit 201 is used to receive downhole temperature data, execute thermal field control algorithms and output power control commands for each heating section. It has a built-in proportional-integral-derivative (PID) adjustment module and a thermal field uniformity calculation module. The ground intelligent control unit 201 is equipped with an over-temperature protection function, which automatically cuts off the power supply to the corresponding heating section when the temperature at any measuring point exceeds the safety threshold.

[0060] The power supply device 202 is connected to the ground intelligent control unit 201 and is used to provide independently adjustable electrical power to each heating section downhole according to power control commands.

[0061] Data acquisition center 203 is used to receive, store and process real-time temperature data uploaded by distributed temperature sensors 205;

[0062] The downhole segmented heater group 204 consists of multiple electric heaters distributed along the shaft axis. Each electric heater corresponds to a heating section and is connected to the surface power supply device 202 via a cable. The power of each heater is independently controllable.

[0063] Distributed temperature sensors 205 are deployed along the axial and radial directions of the wellbore to collect the temperature of each measuring point in real time and transmit it to the data acquisition center 203 via optical fiber or cable.

[0064] In combination with the above Figure 2 , Figure 3 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 1 ,like Figure 3 As shown, this embodiment, based on the above embodiments, provides a method for controlling the dynamic thermal field in a downhole well, including:

[0065] S301. Obtain the initial temperature field data of the target wellbore.

[0066] To obtain the initial temperature field data of the target wellbore, distributed temperature sensors are deployed along the axial and radial directions of the wellbore. These sensors collect the initial temperature data of each measuring point in the wellbore, thereby establishing the initial temperature field distribution of the target wellbore and providing basic temperature data support for subsequent thermal field control calculations.

[0067] S302. Obtain the pre-constructed formation fluid coupling model.

[0068] Obtain a pre-built formation fluid coupling model, which can be used to predict the downhole temperature field distribution at any time.

[0069] In one possible implementation, the process of constructing the formation fluid coupling model includes:

[0070] Obtain the geological and fluid parameters of the target well, including the overall formation density, overall specific heat capacity, and overall thermal conductivity of the target well, as well as the fluid density, specific heat capacity, and axial velocity parameters of the wellbore fluid.

[0071] Based on geological and fluid parameters, determine the corresponding unsteady-state heat conduction control equations;

[0072] Based on the unsteady heat conduction control equation, a formation fluid coupling model in cylindrical coordinates is constructed.

[0073] For example, obtaining the geological and fluid parameters of the target well involves collecting the actual formation density, formation specific heat capacity, and formation thermal conductivity of the target well, as well as the fluid density, fluid specific heat capacity, and fluid axial velocity of the wellbore fluid, providing actual physical parameter support for model construction.

[0074] Based on geological and fluid parameters, the corresponding unsteady-state heat conduction control equations are determined. These equations, constructed by combining various collected geological and fluid parameters, consider the coupling effects of formation heat conduction, fluid convection heat transfer, and the heat source of the downhole heater. These equations reflect the relationship between temperature changes over time and heat conduction and the heat source. The specific unsteady-state heat conduction control equations are as follows:

[0075]

[0076] in, For the overall density of the strata, For the overall specific heat capacity of the formation, For temperature, For time, The overall thermal conductivity of the strata, For the Laplace operator, in cylindrical coordinates, , The heat source intensity per unit volume (heating by the heater);

[0077] Based on the unsteady-state heat conduction control equations, a formation fluid coupling model in cylindrical coordinates is constructed. This involves expanding the determined unsteady-state heat conduction control equations into their complete form in cylindrical coordinates, incorporating radial and axial heat conduction terms and fluid convection heat-carrying terms, thus forming a formation fluid coupling model capable of predicting the target downhole temperature field distribution at any given time. The specific unsteady-state heat conduction control equations in cylindrical coordinates are as follows:

[0078]

[0079] in, Radial distance, For axial coordinates, For the wellbore fluid density, Specific heat capacity of the fluid The axial velocity of the fluid.

[0080] S303. Based on the initial temperature field data and the formation fluid coupling model, calculate the total first energy supply power of each heating section in the target well.

[0081] First, the radial heat flux density is calculated based on the radial heat transfer characteristics between the wellbore and the formation. Then, the wellbore is divided into multiple heating sections along the axial direction. Based on the thermal balance relationship, the total power is decomposed into heat dissipation loss, regulation and maintenance, and formation heat storage power. The total power of the first energy supply required for each heating section is then calculated.

[0082] S304. Based on the total power of the first energy supply, the heating sections of the target well are heated in segments to obtain the first real-time temperature data of each heating section of the target well.

[0083] The power supply device is controlled by the ground intelligent control unit, which provides corresponding power to each heating section according to the calculated power. At the same time, the distributed temperature sensors collect the temperature data of each heating section according to the set sampling period to obtain the first real-time temperature data.

[0084] S305. Determine the corresponding first downhole thermal field uniformity based on the first real-time temperature data.

[0085] The average temperature of all heating sections is calculated based on the first real-time temperature data of each heating section. Then, by using the thermal field uniformity evaluation function and combining the deviation between the measured temperature and the average temperature of each heating section, the first downhole thermal field uniformity, which characterizes the degree of thermal field uniformity, is calculated. The value ranges from 0 to 1.

[0086] S306. Determine the corresponding thermal field control state based on the first downhole thermal field uniformity and the first real-time temperature data.

[0087] In one possible implementation, determining the corresponding thermal field control state based on the first downhole thermal field uniformity includes:

[0088] Obtain the preset thermal field uniformity threshold and allowable temperature deviation value;

[0089] If the uniformity of the first downhole thermal field and the first real-time temperature data satisfy multiple of the following judgment conditions, then the thermal field control state is determined to be a stable and compliant state. If any judgment condition is not satisfied, then the thermal field control state is determined to be a state requiring adjustment. The multiple judgment conditions include:

[0090] Based on the thermal field uniformity threshold and the first downhole thermal field uniformity, it is determined that the first downhole thermal field uniformity is greater than or equal to the uniformity threshold.

[0091] Based on the first real-time temperature data and the allowable temperature deviation value, it is determined that the first real-time temperature data is within the numerical range formed by the temperature control target value and the allowable temperature deviation value.

[0092] For example, obtaining the preset thermal uniformity threshold and temperature deviation allowable value is to retrieve the pre-set thermal uniformity threshold and temperature deviation allowable value. The thermal uniformity threshold is the standard value that the thermal uniformity needs to reach, and the temperature deviation allowable value is the maximum range that the heating section temperature can deviate from the temperature control target value, providing a judgment standard for judging the thermal control status.

[0093] If the uniformity of the first downhole thermal field and the first real-time temperature data meet the following multiple judgment conditions, the thermal field control state is determined to be a stable and qualified state. If any judgment condition is not met, the thermal field control state is determined to be a state to be adjusted. The first downhole thermal field uniformity and the first real-time temperature data are compared with the judgment criteria. If multiple conditions are met, it means that the thermal field control has achieved the target. If any condition is not met, it means that the thermal field control has not achieved the target and further adjustment is required.

[0094] Based on the thermal field uniformity threshold and the first downhole thermal field uniformity, it is determined that the first downhole thermal field uniformity is greater than or equal to the uniformity threshold. This involves comparing the actual calculated first downhole thermal field uniformity with the preset thermal field uniformity threshold to determine whether the actual thermal field uniformity meets the set standard requirements.

[0095] Based on the first real-time temperature data and the allowable temperature deviation value, it is determined that the first real-time temperature data is within the numerical range formed by the temperature control target value and the allowable temperature deviation value. The qualified temperature range is determined based on the temperature control target value and the allowable temperature deviation value. Then, the first real-time temperature data of each heating section is checked one by one to see if they all fall within the range, and it is determined whether the actual temperature of each heating section meets the control requirements.

[0096] S307. If the thermal field control state is stable and meets the standard, then maintain the first total energy supply power of each heating section in the target well.

[0097] As provided in S306 above, when the uniformity of the first downhole thermal field is greater than or equal to the uniformity threshold, and the first real-time temperature data of all heating sections are within the numerical range formed by the temperature control target value and the temperature deviation allowable value, it is determined that the thermal field control has reached a stable and compliant state, and the current total power of the first energy supply of each heating section continues to operate.

[0098] S308. If the thermal field control state is to be adjusted, the total power of the first energy supply is adjusted to obtain the adjusted total power of the second energy supply.

[0099] If any of the above judgment conditions provided in S306 are not met, the thermal field control state is determined to be in an adjustment state. Based on the deviation between the real-time temperature of each heating section and the target set temperature, the power adjustment amount is calculated through the PID control algorithm to correct the first total energy supply power and obtain the second total energy supply power.

[0100] This application provides a method for downhole dynamic thermal field control. It acquires initial temperature field data to provide fundamental data support for thermal field control, improving the accuracy of the initial control basis; acquires a pre-constructed formation fluid coupling model to provide a reliable technical carrier for power calculation, enhancing the rationality of the calculation logic; calculates the total power of the first energy supply to achieve precise preset energy supply, improving the accuracy of initial power configuration; performs segmented heating and acquires the first real-time temperature data to provide real-time basis for judging the thermal field state, improving the flexibility of control response; determines the uniformity of the first downhole thermal field to achieve quantitative judgment of the thermal field state, improving the accuracy of state judgment; determines the thermal field control state to clarify the subsequent control direction, enhancing the pertinence of control decisions; and maintains or adjusts power according to the state to ensure dynamic adaptation of energy supply, improving the flexibility and accuracy of thermal field control. Overall, it achieves the technical effect of improving the accuracy of downhole dynamic thermal field control and enhancing the real-time matching capability between energy supply and formation heat demand.

[0101] Figure 4 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 2 ,like Figure 4 As shown, this embodiment, based on the above embodiments, provides a detailed explanation of the calculation process for the total power of the first energy supply, including:

[0102] S401. Based on the initial temperature field data and the formation fluid coupling model, determine the radial heat flux density from the target wellbore to the formation.

[0103] By combining initial temperature field data from the target well with a formation fluid coupling model showing predictable temperature field distribution, and based on the steady-state radial heat conduction principle, the radial heat flux density per unit length lost from the wellbore to the formation is obtained using the radial heat flux density calculation formula. This provides data for calculating heat dissipation loss power. Parameters such as wellbore temperature and far-end formation temperature can be substituted into the formula, combined with the overall formation thermal conductivity, wellbore radius, and thermal influence radius, to accurately calculate the radial heat flux density at the corresponding location. Differences in parameters at different well depths will correspond to different calculation results. The formula for calculating radial heat flux density is as follows:

[0104]

[0105] in, The radial heat flux density per unit length of the wellbore. The wellbore temperature; The formation temperature (far-end temperature) at the thermally affected boundary. Where is the wellbore radius; The radius of thermal influence; This represents the overall thermal conductivity of the formation.

[0106] Optionally, Figure 5 A schematic diagram of a radial cross-section of wellbore-formation heat exchange is provided for an embodiment of this application, as shown below. Figure 5 As shown, the above S401 step can be understood in conjunction with the schematic diagram of the radial profile of the wellbore-formation heat exchange. Heat is transferred from the heater in the center of the wellbore outward through the tubing, casing, and cement sheath to the near-wellbore formation and the far-wellbore formation. The radial temperature decreases exponentially along the radial distance coordinate direction. This profile feature provides an intuitive physical model support for the calculation of radial heat flux density.

[0107] Optionally, Figure 6 A graph of radial heat flux density versus radial distance is provided for embodiments of this application. The calculated radial heat flux density can be obtained through... Figure 6 The curves showing radial heat flux density versus radial distance are presented, with the horizontal axis representing the radial distance from the wellbore and the vertical axis representing the radial heat flux density. The curves clearly demonstrate the decay law of radial heat flux density with radial distance under different heating times. It can be intuitively seen that the radial heat flux density decays exponentially with distance, and the thermal influence range expands with the extension of heating time, but the decay rate decreases.

[0108] S402. Obtain the length parameters of each heating section in the target well. Based on the radial heat flux density and the length parameters of each heating section in the target well, determine the heat dissipation loss power of each heating section in the target well.

[0109] First, collect the length parameters of each heating segment after dividing the target well along the axial direction. Then, multiply the radial heat flux density per unit length with the corresponding heating segment length parameter to obtain the heat power lost by each heating segment through the wellbore to the surrounding formation. The length parameters of each segment can be determined according to the segment division criteria. Multiplying the radial heat flux density of different heating segments by their corresponding length parameters yields the specific heat loss power value for each heating segment, ensuring the accuracy of the calculation. The formula for calculating the heat loss power is as follows:

[0110]

[0111] in, This refers to the power loss due to heat dissipation, that is, the power of heat lost from the heating section to the surrounding formation through the well wall. The radial heat flux density per unit length of the wellbore. Let be the length parameter of the i-th heating section in the target well.

[0112] S403. Obtain the preset target temperature control values ​​for each heating section in the downhole well.

[0113] The system retrieves the pre-set temperature control target values ​​for each heating section of the target well. These values ​​represent the temperature standards that the thermal field control needs to achieve, providing a core reference for subsequent calculations of formation thermal storage power and control maintenance power. Adaptive temperature control target values ​​can be set for different heating sections based on varying downhole application conditions, or uniform temperature control target values ​​can be set for each heating section according to the operating conditions to match actual heating requirements.

[0114] S404. Obtain the difference between the thermally affected radius and the wellbore radius of the target well, and the time-varying rate of the average temperature of the heating section.

[0115] The difference between the thermally affected radius and the wellbore radius calculated from the target wellbore is collected. Simultaneously, the rate of change of the average temperature over time in each heating section of the target well is obtained. These two values ​​are key fundamental parameters for calculating formation thermal storage power. The thermally affected radius can be determined through a combination of measurements and calculations. The difference is calculated using the wellbore radius, and the rate of change of the average temperature over time in the heating section is calculated using real-time temperature data, ensuring parameter accuracy.

[0116] S405. Based on the initial temperature field data, the target temperature control value, and the formation fluid coupling model, combined with the formation comprehensive density, comprehensive specific heat capacity, the difference between the thermal influence radius and the wellbore radius, the length parameters of each heating section downhole, and the time change rate of the average temperature of the heating section, determine the formation thermal storage power.

[0117] By integrating initial temperature field data, target temperature control values, formation fluid coupling models, and various fundamental parameters, the power required to raise the formation temperature from its initial value to the target temperature control value is obtained through the formation thermal storage power calculation formula. Various parameters can be substituted sequentially into the thermal storage power formula to first calculate the volume of the heat-affected zone, and then, by combining the formation's overall density, overall specific heat capacity, and the time-varying rate of change of the average temperature in the heating section, the formation thermal storage power for each heating section can be calculated, closely aligning with actual thermal storage requirements. The specific calculation formula for formation thermal storage power is as follows:

[0118]

[0119] in, For the thermal storage capacity of the formation, Where is the wellbore radius; For the heat-affected radius, The average temperature change over time in the heating section is denoted as . Let be the length parameter of the i-th heating section in the target well. For the overall density of the strata, This represents the overall specific heat capacity of the formation.

[0120] S406. Substitute the initial temperature field data and the target temperature control value into the formation fluid coupling model to obtain the radial heat flux density from the target wellbore to the formation, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient. Based on the radial heat flux density, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient, determine the radial heat transfer characteristics from the target wellbore to the formation.

[0121] By substituting the initial temperature field data and the target temperature control value into the formation fluid coupling model, key heat transfer parameters such as radial heat flux density are calculated. Then, parameter analysis clarifies the laws and characteristics of heat transfer between the wellbore and the formation. Various heat transfer parameters can be obtained through numerical solution of the model, and the correlation and variation laws between parameters can be analyzed to determine the radial heat transfer characteristics at different well depths and different heating stages, reflecting the actual heat transfer state.

[0122] S407. Determine the control and maintenance power based on the initial temperature field data, the temperature control target value, the formation fluid coupling model, and the radial heat transfer characteristics.

[0123] By combining initial temperature field data and target temperature control values, and relying on the formation fluid coupling model and well-defined radial heat transfer characteristics, the power required to maintain the temperature of each heating section near the target temperature control value can be calculated. Based on the heat transfer patterns within the radial heat transfer characteristics and the temperature changes predicted by the model, the power required to offset heat transfer losses and maintain the target temperature control value can be calculated. Different heat transfer characteristics correspond to different control and maintenance power values.

[0124] S408. The heat loss power, regulation and maintenance power and formation heat storage power are summed to obtain the first total energy supply power of each heating section in the target well.

[0125] The total energy supply power required for thermal field control in each heating section of the target well is obtained by summing the three power values: heat dissipation loss power, regulation and maintenance power, and formation heat storage power. The calculated power values ​​for each heating section can be added together to obtain the first total energy supply power specific to each heating section of the target well. This provides a precise power control basis for segmented heating, adapting to the energy requirements of each section. The specific formula for summing the first total energy supply power is as follows:

[0126]

[0127] in, This is the total input power (i.e., the total power of the first energy supply). To dissipate heat and reduce power loss, The power required to regulate the heating process, i.e., to maintain the temperature of the heating section near the target value. This refers to the thermal storage capacity of the formation.

[0128] Figure 7 This application provides an embodiment of an energy supply power versus well depth curve, from which the calculated total energy supply power for each heating section can be obtained. Figure 7 The curves showing the relationship between energy supply power and well depth, with the horizontal axis representing well depth and the vertical axis representing supply power, clearly demonstrate the distribution pattern of the total first energy supply power corresponding to different well depth heating sections, and intuitively reflect the influence of well depth and temperature on energy supply power.

[0129] It is important to note that Figures 5 to 7 This is merely an illustrative demonstration and is not intended as an improvement, nor does it affect the scope of protection of this application.

[0130] The downhole dynamic thermal field control method provided in this application determines the radial heat flux density by combining initial temperature field data with a formation fluid coupling model, providing accurate data for calculating heat dissipation loss power; it calculates heat dissipation loss power by using radial heat flux density and heating section length parameters, accurately quantifying the formation heat loss in each heating section; it obtains the temperature control target value, clarifying the core temperature standard for subsequent power calculations; it obtains the thermal influence radius correlation difference and the time change rate of the average temperature of the heating section, providing necessary key parameters for calculating formation heat storage power; it integrates multiple types of data and parameters to determine formation heat storage power, accurately matching the actual energy demand for formation heating; it substitutes into the model to determine radial heat transfer characteristics, clearly understanding the heat transfer law between the wellbore and the formation; it determines the control and maintenance power based on multiple factors, providing a power basis for stably maintaining the temperature control target value; and it sums the three types of power to obtain the first energy supply total power, achieving accurate quantification of the energy demand of each heating section and providing a scientific power configuration basis for segmented heating.

[0131] Figure 8 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 3 ,like Figure 8 As shown, this embodiment, based on the above embodiments, provides a detailed explanation of the process for determining the uniformity of the first downhole thermal field, including:

[0132] S801. Based on the first real-time temperature data, determine the average temperature data of all heating sections in the target well.

[0133] Collect the first real-time temperature data of each heating section in the target well, determine the total number of heating sections, sum the first real-time temperature data of all heating sections, and then divide the sum by the total number of heating sections to obtain the average temperature data of all heating sections in the target well, providing a basic value for calculating the thermal field uniformity.

[0134] Specifically, the first real-time temperature data of each heating section can be summarized and the data integrity can be verified. Then, the average value can be calculated by the arithmetic mean method to ensure the accuracy of the average temperature data calculation.

[0135] S802. Based on the first real-time temperature data and the average temperature data, determine the corresponding first downhole thermal field uniformity using a preset uniformity calculation formula.

[0136] The difference between the first real-time temperature data of each heating section and the average temperature data is calculated and squared. The sum of all squared results is then divided by the total number of heating sections, and the square root is taken. The average temperature data is used as the denominator and divided by the above result. Finally, the calculated value is subtracted from 1 to obtain the dimensionless first downhole thermal field uniformity. This can be calculated step-by-step by substituting the first real-time temperature data and average temperature data of each heating section into the formula. The result takes a value between 0 and 1; the closer the value is to 1, the better the thermal field uniformity, thus accurately quantifying the uniformity of the downhole thermal field. The functional expression for the downhole thermal field uniformity is:

[0137]

[0138] Where E is the thermal field uniformity, and its value ranges from [value range missing]. , This is the first real-time temperature data for the i-th heating segment. This represents the average temperature data for all heating sections, where n is the total number of heating sections.

[0139] Figure 9 The curve of thermal field uniformity versus control time provided in the embodiments of this application shows that the calculated first downhole thermal field uniformity can be obtained through... Figure 9 The curves showing thermal field uniformity versus control time are presented, with the horizontal axis representing control time and the vertical axis representing thermal field uniformity. This allows for a direct comparison of the differences in thermal field uniformity under dynamic control and no control modes, clearly reflecting the process of increasing thermal field uniformity in the first well with control time.

[0140] It is important to note that Figure 9 This is merely an illustrative demonstration and is not intended as an improvement, nor does it affect the scope of protection of this application.

[0141] The downhole dynamic thermal field control method provided in this application calculates the average temperature data of all heating sections using first real-time temperature data, providing a unified reference benchmark for the quantitative calculation of thermal field uniformity and ensuring clear comparative values ​​for subsequent calculations. Combining the first real-time temperature data and the average temperature data, the first downhole thermal field uniformity is calculated using a preset formula, realizing a quantitative evaluation of the downhole thermal field uniformity. This method can intuitively reflect the temperature dispersion of each heating section and provides core numerical basis for determining the thermal field control state.

[0142] Figure 10 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 4 ,like Figure 10 As shown, this embodiment, based on the above embodiments, provides a detailed explanation of the process for obtaining the total power of the second energy supply, including:

[0143] S1001. If the thermal field control state is to be adjusted, then determine the temperature deviation data between the first real-time temperature data of each heating section in the target well and the temperature control target value.

[0144] When it is determined that the thermal field control has not reached a stable and qualified state, the first real-time temperature data of each heating section in the target well is calculated by subtracting the corresponding temperature control target value to obtain independent temperature deviation data for each heating section, providing a direct deviation basis for power adjustment.

[0145] Specifically, the temperature deviation data can be calculated for each heating segment one by one. The first real-time temperature data of the corresponding heating segment is subtracted from the temperature control target value to accurately obtain the specific value of the temperature deviation from the target value for each segment. Different heating segments will yield different temperature deviation data results.

[0146] S1002, Obtain the preset proportional-integral-derivative controller.

[0147] In this embodiment, the proportional-integral-derivative (PID) controller is a multi-segment independent PID controller.

[0148] The pre-configured proportional-integral-derivative (PID) controller is retrieved. This controller has a separate control module for each heating section of the target well. Each module operates independently and its parameters can be set individually, enabling differentiated adjustment of the power of each heating section.

[0149] Specifically, a corresponding number of independent control modules can be matched according to the number of downhole heating sections. Each module is preset with appropriate proportional, integral, and derivative adjustment coefficients. Each module only controls the temperature deviation of the corresponding heating section and does not interfere with each other.

[0150] S1003. Taking the uniformity of the first downhole thermal field as the global optimization target, the power adjustment amount of each heating section of the target downhole is determined based on the proportional-integral-derivative controller and temperature deviation data.

[0151] The goal of overall control is to improve the uniformity of the downhole thermal field in the first well. The temperature deviation data of each heating section is input into the corresponding proportional-integral-derivative controller module. Through the proportional, integral and derivative operations of the controller, the power value that needs to be adjusted for each heating section is obtained, so as to realize the differentiated allocation of power.

[0152] S1004. Adjust the total power of the first energy supply according to the power adjustment amount to obtain the total power of the second energy supply.

[0153] The calculated power adjustment amount for each heating section is calculated and then compared with the total first energy supply power of the corresponding heating section. The original power is then increased or decreased to obtain the adjusted total second energy supply power for each heating section, providing a new power basis for subsequent reheating.

[0154] Specifically, the direction of power adjustment can be determined based on the sign of the temperature deviation. If the temperature is too low, the power is increased; if the temperature is too high, the power is decreased. The power adjustment amount is directly added to the total power of the first energy supply to obtain the total power of the second energy supply, thus ensuring the accuracy of power adjustment.

[0155] The downhole dynamic thermal field control method provided in this application accurately quantifies the degree of deviation between the temperature of each heating segment and the target value by calculating the temperature deviation data of each heating segment, providing an intuitive numerical basis for power adjustment; it calls up multiple independent proportional-integral-derivative controllers to realize independent power control of each heating segment, adapting to the differentiated needs of different heating segments downhole; it uses thermal field uniformity as the global target and combines the controller to calculate the power adjustment amount, so that the power adjustment takes into account both local temperature deviation and overall thermal field uniformity, realizing coordinated optimization of control; it corrects the original power according to the adjustment amount to obtain a new total replenishment power, providing a precise power configuration for reheating, and can quickly bring the thermal field closer to a stable and compliant state.

[0156] Figure 11 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 5 ,like Figure 11 As shown, this embodiment, based on the above embodiments, provides a detailed explanation of the specific process for determining the power adjustment amount, including:

[0157] S1101. Based on the temperature deviation data of each heating section in the target well, determine the corresponding real-time value, integral value, differential value and absolute value respectively.

[0158] Real-time values ​​of temperature deviation data for each heating section are extracted. The integral value is obtained by integrating the temperature deviation data over time, and the differential value is obtained by performing differentiation. At the same time, the absolute value of the temperature deviation data is calculated to provide multi-dimensional deviation parameters for power adjustment calculation.

[0159] Specifically, temperature deviation data can be continuously collected according to the control cycle, and the time integral and differential results of the real-time values ​​can be calculated segment by segment. The non-negative result of the deviation value is directly taken as the absolute value to ensure that each parameter corresponds one-to-one with the heating segment and that the data is accurate.

[0160] S1102. Based on the proportional-integral-derivative controller, determine the first adjustment coefficient corresponding to the real-time value, the second adjustment coefficient corresponding to the integral value, and the third adjustment coefficient corresponding to the derivative value.

[0161] From multiple independent proportional-integral-derivative (PID) controllers, the first adjustment coefficient matching the real-time temperature deviation value, the second adjustment coefficient matching the integral value, and the third adjustment coefficient matching the derivative value are retrieved. These three types of coefficients are the proportional, integral, and derivative adjustment coefficients, which are the core weighting parameters for power calculation.

[0162] Specifically, three types of adjustment coefficients can be independently set for each controller according to the downhole heating conditions. The coefficient values ​​can be dynamically adjusted according to the control requirements. The coefficients for different heating sections can be configured separately to adapt to different deviations.

[0163] S1103. Sort each heating section of the target well from largest to smallest according to its absolute value to obtain the corresponding sorting result.

[0164] The absolute values ​​of the temperature deviation data of each heating section are compared, and all heating sections are arranged in descending order to obtain the order of the heating sections, which determines the priority for the segment-by-segment calculation of power adjustment.

[0165] Specifically, the absolute values ​​of each heating segment can be summarized and sorted in descending order. The heating segment number corresponding to each value can be recorded to form a clear sorting result. The heating segment with the larger absolute value will be ranked higher in the sorting and will be given priority for power adjustment calculation.

[0166] S1104. Based on the real-time value, integral value, differential value, first adjustment coefficient, second adjustment coefficient, and third adjustment coefficient, and combined with the sorting results, determine the power adjustment amount of each heating section in the target well in sequence.

[0167] Based on real-time values, integral values, differential values, the first adjustment coefficient, the second adjustment coefficient, and the third adjustment coefficient, and combined with the ranking results, the power adjustment amount for each heating section in the target well is determined sequentially. This is done by multiplying the real-time value of each heating section by the first adjustment coefficient, the integral value by the second adjustment coefficient, and the differential value by the third adjustment coefficient, according to the order of the ranking results. The three calculation results are then summed to obtain the power adjustment amount for each heating section, achieving differentiated power adjustment calculations. The specific formula for the power adjustment amount is as follows:

[0168]

[0169] in, For power adjustment amount, This is temperature deviation data. The target value for temperature control, The first real-time temperature data for the i-th heating section in the target well. , , These are the first adjustment coefficient, second adjustment coefficient, and third adjustment coefficient corresponding to proportional, integral, and derivative operations, respectively.

[0170] Specifically, the corresponding parameters can be substituted into each segment according to the sorting results for calculation. The heating segment with the largest absolute deviation value is calculated first. The positive or negative result corresponds to the direction of power increase or decrease, ensuring that the adjustment amount matches the actual deviation of each segment.

[0171] S1105. Based on the power adjustment amount, the total first energy supply power of each heating section in the target well is adjusted segment by segment to obtain the total second energy supply power of each heating section.

[0172] According to the sorting results, the power adjustment amount of each heating segment is sequentially algebraically calculated with the total first energy supply power of the corresponding heating segment to correct the original power and obtain the adjusted total second energy supply power segment by segment, providing a new power basis for segmented heating.

[0173] Specifically, the calculation method can be determined based on the sign of the power adjustment amount: positive values ​​are added and negative values ​​are subtracted. Power correction is completed segment by segment, and the adjustments of each segment do not interfere with each other, ensuring that the adjusted power accurately matches the thermal field control requirements of each segment.

[0174] The downhole dynamic thermal field control method provided in this application extracts multi-dimensional parameters from temperature deviation data, providing a comprehensive basis for accurate calculation of power adjustment, ensuring that the adjustment calculation closely matches the real-time change characteristics of the deviation; it retrieves three types of adjustment coefficients from the controller, assigning appropriate control weights to the deviation parameters to ensure that the calculation results match the actual control requirements; it sorts the heating sections according to the absolute value of the deviation, clarifying the priority of power adjustment, allowing heating sections with large deviations to be controlled first; it calculates the power adjustment amount by combining multiple parameters and the sorting results, realizing differentiated and accurate adjustment calculations for each heating section, balancing control efficiency and effectiveness; it corrects the total power of the first energy supply segment by segment to obtain new power, providing accurate segmented power configuration for reheating, and can quickly promote the thermal field to converge towards a stable and compliant state.

[0175] Figure 12 A flowchart illustrating the downhole dynamic thermal field control method provided in this application embodiment. Figure 6 ,like Figure 12 As shown, this embodiment, based on the above embodiment, provides supplementary explanations of the subsequent process for obtaining the adjusted total power of the second energy supply, including:

[0176] S1201. According to the preset control cycle, continuously acquire the second real-time temperature data of each heating section of the target well.

[0177] According to the pre-set thermal field control cycle, the temperature of each heating section in the target well is collected by distributed temperature sensors, and the second real-time temperature data of each heating section is continuously acquired to provide the latest temperature basis for subsequent thermal field evaluation.

[0178] Specifically, the control cycle of the ground intelligent control unit can be set to 1~10 minutes. Distributed temperature sensors continuously collect the temperature of each heating section measurement point according to this cycle, transmit and store the data in real time, ensure the continuity and timeliness of the data, and adapt to the control rhythm of different heating conditions.

[0179] Figure 13 This application provides a temperature versus time graph, and the specific process of S801 described above can be achieved through... Figure 13 The temperature versus time curves shown have the horizontal axis representing the control time and the vertical axis representing the temperature at the downhole measuring point. The curves clearly demonstrate the temperature variation of each heating section with the control time, and allow for a direct view of the entire process from the initial rapid temperature rise, the decrease in the rate of temperature rise in the middle stage, to the approach of the temperature control target value in the later stage.

[0180] It is important to note that Figure 13 This is merely an illustrative demonstration and is not intended as an improvement, nor does it affect the scope of protection of this application.

[0181] S1202. Determine the corresponding second downhole thermal field uniformity based on the second real-time temperature data.

[0182] Collect the second real-time temperature data of each heating section, first calculate the average temperature data of all heating sections, then substitute the temperature data of each section into the preset uniformity calculation formula, and finally obtain the second downhole thermal field uniformity that represents the current thermal field state through a series of calculations such as deviation square, averaging, and square root.

[0183] Specifically, the average temperature can be calculated using the arithmetic mean method, and then the sum of squares of the deviations between the temperature and the average value can be calculated segment by segment to complete the step-by-step calculation of the formula. The result is between 0 and 1, which accurately reflects the uniformity of the thermal field after adjusting the power.

[0184] S1203. Determine the corresponding thermal field control state based on the uniformity of the second downhole thermal field.

[0185] The preset thermal field uniformity threshold and temperature deviation allowable value are retrieved. First, it is determined whether the thermal field uniformity of the second well is greater than or equal to the thermal field uniformity threshold. Then, it is checked whether the second real-time temperature data of each heating section is within the range formed by the temperature control target value and the deviation allowable value. Based on the dual judgment results, the thermal field control status is determined to be either a stable and compliant state or a state to be adjusted.

[0186] Specifically, the numerical determination of the uniformity of the downhole thermal field can be completed first, and then the temperature data can be verified segment by segment. If both conditions are met, the state is stable and meets the standards; if either condition is not met, the state is to be adjusted. The determination results provide a clear direction for subsequent control.

[0187] S1204. If the thermal field control state is stable and meets the standard, then maintain the total power of the second energy supply.

[0188] After determining that the thermal field control has reached a stable and satisfactory state, the total power of the second energy supply configured for each heating section of the target well remains unchanged, and the power is continued to provide electrical power to each heating section at this power, so that the downhole thermal field is maintained in the target stable state.

[0189] Specifically, the power output value of each heating section can be locked through the ground intelligent control unit, and the power supply device will continuously supply power at that power while maintaining continuous collection of temperature data to monitor whether the thermal field status changes in real time.

[0190] Optionally, after the thermal field regulation reaches a stable and satisfactory state, the current heating efficiency can be calculated using the heating efficiency calculation formula. The effective heating power is the total power of the second energy supply minus the power loss due to heat dissipation, thereby quantifying the energy utilization effectiveness under this power operating state. Simultaneously, the thermal field regulation response time can be calculated using the thermal field regulation response time calculation formula, thereby quantifying the system's response speed from the initial state to the target stable state. The power output value of each heating segment can be locked by the ground intelligent control unit, and the power supply device continuously supplies power at this power while maintaining continuous temperature data acquisition to monitor whether the thermal field state changes in real time. The specific heating efficiency calculation formula is as follows:

[0191]

[0192] in, For heating efficiency, The effective heating power is (i.e., the total power of the second energy supply minus the power lost due to heat dissipation). This is the total power supplied as the second energy source.

[0193] The specific formula for calculating the response time of thermal field control is as follows:

[0194]

[0195] in, For thermal field control response time, For the overall density of the strata, For the overall specific heat capacity of the formation, To control the volume of the heating section, For the target temperature rise, This is to replenish the total power for the second energy supply. Power loss is due to heat dissipation.

[0196] S1205. If the thermal field control state is in a state to be adjusted, then adjust the total power of the second energy supply according to the state to be adjusted until the thermal field control state is in a stable and compliant state.

[0197] After determining that the thermal field control is in a state of needing adjustment, the temperature deviation data of each heating section is recalculated, and a new power adjustment amount is determined through a proportional-integral-derivative controller. The total power of the second energy supply is corrected, and the process of collecting temperature, evaluating uniformity, and determining the state is repeated. The power is continuously adjusted until the thermal field reaches a stable and compliant state.

[0198] Specifically, the new adjustment amount can be calculated segment by segment according to the power adjustment logic described above, the power of each segment can be dynamically corrected, and the control process can be executed cyclically until the uniformity of the thermal field and the temperature meet the preset requirements.

[0199] The downhole dynamic thermal field control method provided in this application continuously acquires second real-time temperature data at a preset cycle, providing continuous and real-time temperature data support for subsequent determination of the thermal field control state, ensuring that the determination results are consistent with the actual changes in the thermal field; the second downhole thermal field uniformity is calculated based on the new temperature data, realizing a quantitative evaluation of the thermal field uniformity after power adjustment, and intuitively reflecting the actual effect of the adjustment measures; the thermal field control state is determined based on the uniformity, and the dual determination clarifies whether the thermal field meets the standard, providing a clear decision basis for whether to continue adjusting the power; after meeting the standard, the total power of the second energy supply is maintained, which can stabilize the downhole thermal field in the target state and ensure the stability of thermal field control; if the standard is not met, the power is continuously adjusted until the standard is met, forming a closed-loop thermal field control process, which can continuously optimize the thermal field state and ultimately achieve precise and stable control of the downhole thermal field.

[0200] Figure 14 This is a schematic diagram of the downhole dynamic thermal field control device provided in an embodiment of this application. The device in this embodiment can be in the form of software and / or hardware. For example... Figure 14 As shown in the embodiment of this application, the downhole dynamic thermal field control device 1400 includes: a first acquisition module 1401, a second acquisition module 1402, a calculation module 1403, a first processing module 1404, a first determination module 1405, a second determination module 1406, a second processing module 1407, and a third processing module 1408.

[0201] The first acquisition module 1401 is used to acquire the initial temperature field data of the target downhole wellbore;

[0202] The second acquisition module 1402 is used to acquire a pre-constructed formation fluid coupling model;

[0203] Calculation module 1403 is used to calculate the total first energy supply power of each heating section in the target well based on the initial temperature field data and the formation fluid coupling model;

[0204] The first processing module 1404 is used to perform segmented heating of each heating section of the target well according to the first total energy supply power, so as to obtain the first real-time temperature data of each heating section of the target well.

[0205] The first determining module 1405 is used to determine the corresponding first downhole thermal field uniformity based on the first real-time temperature data.

[0206] The second determining module 1406 is used to determine the corresponding thermal field control state based on the first downhole thermal field uniformity and the first real-time temperature data.

[0207] The second processing module 1407 is used to maintain the total first energy supply power of each heating section of the target well if the thermal field control state is stable and meets the standard.

[0208] The third processing module 1408 is used to adjust the first total energy supply power if the thermal field control state is in an unadjustable state, so as to obtain the adjusted second total energy supply power.

[0209] In one possible implementation, the second acquisition module 1402 is further configured to:

[0210] Obtain the geological and fluid parameters of the target well, including the overall formation density, overall specific heat capacity, and overall thermal conductivity of the target well, as well as the fluid density, specific heat capacity, and axial velocity parameters of the wellbore fluid.

[0211] Based on geological and fluid parameters, determine the corresponding unsteady-state heat conduction control equations;

[0212] Based on the unsteady heat conduction control equation, a formation fluid coupling model in cylindrical coordinates is constructed.

[0213] In one possible implementation, the computing module 1403 is further configured to:

[0214] Based on the initial temperature field data and the formation fluid coupling model, the radial heat flux density from the target wellbore to the formation is determined;

[0215] Obtain the length parameters of each heating section in the target well;

[0216] The heat loss power of each heating section in the target well is determined based on the radial heat flux density and the length parameters of each heating section in the target well.

[0217] Obtain the preset target temperature control values ​​for each heating section in the downhole well;

[0218] Based on the initial temperature field data, the formation fluid coupling model, and the temperature control target value, the control and maintenance power required to maintain the temperature control target value in each heating section and the formation thermal storage power required to raise the initial temperature to the temperature control target value are determined respectively.

[0219] The power loss due to heat dissipation, the power for regulation and maintenance, and the power for formation heat storage are summed to obtain the total first energy supply power for each heating section of the target well.

[0220] In one possible implementation, the computing module 1403 is further configured to:

[0221] Obtain the difference between the thermally affected radius and the wellbore radius downhole, and the time rate of change of the average temperature of the heated section;

[0222] Based on the initial temperature field data, the target temperature control value, and the formation fluid coupling model, combined with the formation comprehensive density, comprehensive specific heat capacity, the difference between the thermal influence radius and the wellbore radius, the length parameters of each heating section downhole, and the time change rate of the average temperature of the heating section, the formation thermal storage power is determined.

[0223] Substitute the initial temperature field data and the target temperature control value into the formation fluid coupling model to obtain the radial heat flux density from the target wellbore to the formation, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient.

[0224] The radial heat transfer characteristics of the target wellbore to the formation are determined based on the radial heat flux density, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient.

[0225] Based on the initial temperature field data, the target temperature control value, the formation fluid coupling model, and the radial heat transfer characteristics, the control maintenance power is determined.

[0226] In one possible implementation, the first determining module 1405 is further configured to:

[0227] Based on the first real-time temperature data, determine the average temperature data of all heating sections in the target well.

[0228] Based on the first real-time temperature data and average temperature data, the corresponding first downhole thermal field uniformity is determined using a preset uniformity calculation formula.

[0229] In one possible implementation, the second determining module 1406 is further configured to:

[0230] Obtain the preset thermal field uniformity threshold and allowable temperature deviation value;

[0231] If the uniformity of the first downhole thermal field and the first real-time temperature data satisfy multiple of the following judgment conditions, then the thermal field control state is determined to be a stable and compliant state. If any judgment condition is not satisfied, then the thermal field control state is determined to be a state requiring adjustment. The multiple judgment conditions include:

[0232] Based on the thermal field uniformity threshold and the first downhole thermal field uniformity, it is determined that the first downhole thermal field uniformity is greater than or equal to the uniformity threshold.

[0233] Based on the first real-time temperature data and the allowable temperature deviation value, it is determined that the first real-time temperature data is within the numerical range formed by the temperature control target value and the allowable temperature deviation value.

[0234] In one possible implementation, the third processing module 1408 is further configured to:

[0235] If the thermal field control status is to be adjusted, then determine the temperature deviation data between the first real-time temperature data of each heating section in the target well and the temperature control target value.

[0236] Obtain a preset proportional-integral-derivative (PID) controller, wherein the PID controller is a multi-segment independent PID controller;

[0237] The uniformity of the first downhole thermal field is taken as the global optimization target. Based on the proportional-integral-derivative controller and temperature deviation data, the power adjustment amount of each heating section in the target downhole is determined.

[0238] The total power of the first energy supply is adjusted according to the power adjustment amount to obtain the total power of the second energy supply.

[0239] In one possible implementation, the third processing module 1408 is further configured to:

[0240] Based on the temperature deviation data of each heating section in the target well, determine the corresponding real-time value, integral value, differential value and absolute value respectively;

[0241] Based on the proportional-integral-derivative controller, the first adjustment coefficient corresponding to the real-time value, the second adjustment coefficient corresponding to the integral value, and the third adjustment coefficient corresponding to the derivative value are determined respectively.

[0242] The heating sections of the target well are sorted from largest to smallest based on their absolute values ​​to obtain the corresponding sorting results;

[0243] Based on the real-time value, integral value, differential value, first adjustment coefficient, second adjustment coefficient, and third adjustment coefficient, and combined with the sorting results, the power adjustment amount of each heating section in the target well is determined in sequence.

[0244] Based on the power adjustment amount, the total first energy supply power of each heating section in the target well is adjusted segment by segment to obtain the total second energy supply power of each heating section.

[0245] In one possible implementation, the third processing module 1408 is further configured to:

[0246] According to the preset control cycle, the second real-time temperature data of each heating section of the target well is continuously acquired;

[0247] Based on the second real-time temperature data, determine the corresponding second downhole thermal field uniformity;

[0248] The corresponding thermal field control state is determined based on the uniformity of the second downhole thermal field.

[0249] If the thermal field regulation is in a stable and compliant state, then maintain the total power of the second energy supply;

[0250] If the thermal field control status is in a state of pending adjustment, the total power of the second energy supply will be adjusted according to the state of pending adjustment until the thermal field control status is in a stable and compliant state.

[0251] The downhole dynamic thermal field control device provided in this embodiment can execute the method provided in the above-mentioned method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0252] Figure 15 This is a schematic diagram of the structure of the downhole dynamic thermal field control device provided in an embodiment of this application. Figure 15 As shown, the downhole dynamic thermal field control device 1500 provided in this embodiment includes at least one processor 1501 and a memory 1502. Optionally, the device 1500 also includes a communication component 1503. The processor 1501, memory 1502, and communication component 1503 are connected via a bus.

[0253] In a specific implementation, at least one processor 1501 executes computer execution instructions stored in memory 1502, causing at least one processor 1501 to perform the above-described method.

[0254] The specific implementation process of processor 1501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0255] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0256] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0257] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0258] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0259] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0260] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0261] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0262] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0263] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0264] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0265] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0266] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0267] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for controlling dynamic thermal fields in downhole wells, characterized in that, include: Acquire the initial temperature field data of the target wellbore; Obtain a pre-constructed formation fluid coupling model; Based on the initial temperature field data and the formation fluid coupling model, calculate the total first energy supply power of each heating section in the target well. The target downhole heating section is heated in segments according to the first total energy supply power to obtain the first real-time temperature data of each heating section of the target downhole. Based on the first real-time temperature data, determine the corresponding first downhole thermal field uniformity; Based on the first downhole thermal field uniformity and the first real-time temperature data, the corresponding thermal field control state is determined; If the thermal field control state is stable and meets the standard, then the total first energy supply power of each heating section of the target well is maintained; If the thermal field control state is in an adjustment state, the first total energy supply power is adjusted to obtain the adjusted second total energy supply power.

2. The method according to claim 1, characterized in that, Before obtaining the pre-built formation fluid coupling model, the following steps are also included: Obtain the geological and fluid parameters of the target well, wherein the geological and fluid parameters include the overall formation density, overall specific heat capacity, and overall thermal conductivity of the target well, as well as the fluid density, specific heat capacity, and axial velocity parameters of the wellbore fluid; Based on the geological and fluid parameters, the corresponding unsteady-state heat conduction control equations are determined; Based on the unsteady heat conduction control equation, a formation fluid coupling model in cylindrical coordinates is constructed.

3. The method according to claim 2, characterized in that, The step of calculating the total first energy supply power of each heating section in the target well based on the initial temperature field data and the formation fluid coupling model includes: Based on the initial temperature field data and the formation fluid coupling model, the radial heat flux density from the target downhole wellbore to the formation is determined; Obtain the length parameters of each heating section in the target downhole well; Based on the radial heat flux density and the length parameters of each heating section in the target well, the heat dissipation loss power of each heating section in the target well is determined; Obtain the preset temperature control target values ​​for each heating section of the target downhole well; Based on the initial temperature field data, the formation fluid coupling model, and the temperature control target value, determine the control and maintenance power required to maintain the temperature control target value in each heating section and the formation thermal storage power required to raise the initial temperature to the temperature control target value. The heat dissipation loss power, the regulation and maintenance power, and the formation heat storage power are summed to obtain the first total energy supply power of each heating section in the target well.

4. The method according to claim 3, characterized in that, The step of determining, based on the initial temperature field data, the formation fluid coupling model, and the temperature control target value, the required control and maintenance power for each heating section to maintain the temperature control target value, and the required formation thermal storage power to raise the initial temperature to the temperature control target value, includes: The difference between the thermally affected radius and the wellbore radius of the target well, and the time rate of change of the average temperature of the heating section are obtained. Based on the initial temperature field data, the temperature control target value, and the formation fluid coupling model, combined with the formation comprehensive density, comprehensive specific heat capacity, the difference between the thermal influence radius and the wellbore radius, the length parameters of each heating section in the target well, and the time change rate of the average temperature of the heating section, the formation thermal storage power is determined. Substitute the initial temperature field data and the target temperature control value into the formation fluid coupling model to obtain the radial heat flux density from the target downhole wellbore to the formation, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient. The radial heat transfer characteristics of the target downhole wellbore to the formation are determined based on the radial heat flux density, the temperature difference between the wellbore and the far end of the formation, and the heat transfer coefficient. The control and maintenance power is determined based on the initial temperature field data, the target temperature control value, the formation fluid coupling model, and the radial heat transfer characteristics.

5. The method according to any one of claims 1-4, characterized in that, The step of determining the corresponding first downhole thermal field uniformity based on the first real-time temperature data includes: Based on the first real-time temperature data, determine the average temperature data of all heating sections in the target well. Based on the first real-time temperature data and the average temperature data, the corresponding uniformity of the first downhole thermal field is determined using a preset uniformity calculation formula.

6. The method according to claim 4, characterized in that, The step of determining the corresponding thermal field control state based on the first downhole thermal field uniformity and the first real-time temperature data includes: Obtain the preset thermal field uniformity threshold and allowable temperature deviation value; If the uniformity of the first downhole thermal field and the first real-time temperature data satisfy the following multiple judgment conditions, then the thermal field control state is determined to be the stable and compliant state; if any of the judgment conditions are not satisfied, then the thermal field control state is determined to be the state to be adjusted. The multiple judgment conditions include: Based on the thermal field uniformity threshold and the first downhole thermal field uniformity, it is determined that the first downhole thermal field uniformity is greater than or equal to the uniformity threshold. Based on the first real-time temperature data and the allowable temperature deviation value, it is determined that the first real-time temperature data is within the numerical range formed by the temperature control target value and the allowable temperature deviation value.

7. The method according to claim 6, characterized in that, If the thermal field control state is a state to be adjusted, then the first total energy supply power is adjusted to obtain the adjusted second total energy supply power, including: If the thermal field control state is the state to be adjusted, then the temperature deviation data between the first real-time temperature data of each heating section of the target well and the temperature control target value is determined. Obtain a preset proportional-integral-derivative (PID) controller, wherein the PID controller is a multi-segment independent PID controller; Using the uniformity of the first downhole thermal field as the global optimization target, the power adjustment amount of each heating section of the target downhole is determined based on the proportional-integral-derivative controller and the temperature deviation data. The first total energy supply power is adjusted according to the power adjustment amount to obtain the second total energy supply power.

8. The method according to claim 7, characterized in that, The step of determining the power adjustment amount for each heating section of the target downhole based on the proportional-integral-derivative controller and the temperature deviation data includes: Based on the temperature deviation data of each heating section in the target well, the corresponding real-time value, integral value, differential value and absolute value are determined respectively; Based on the proportional-integral-derivative controller, a first adjustment coefficient corresponding to the real-time value, a second adjustment coefficient corresponding to the integral value, and a third adjustment coefficient corresponding to the derivative value are determined respectively. The heating sections of the target downhole are sorted from largest to smallest according to the absolute value to obtain the corresponding sorting results; Based on the real-time value, the integral value, the differential value, the first adjustment coefficient, the second adjustment coefficient, and the third adjustment coefficient, and in conjunction with the sorting result, the power adjustment amount of each heating section of the target downhole is determined sequentially. Based on the power adjustment amount, the total first energy supply power of each heating section of the target downhole is adjusted segment by segment to obtain the total second energy supply power of each heating section.

9. The method according to claim 8, characterized in that, After adjusting the first total energy supply power to obtain the adjusted second total energy supply power if the thermal field control state is an unadjustable state, the method further includes: According to the preset control cycle, the second real-time temperature data of each heating section of the target well is continuously acquired; Based on the second real-time temperature data, determine the corresponding second downhole thermal field uniformity; The corresponding thermal field control state is determined based on the second downhole thermal field uniformity. If the thermal field control state is the stable and compliant state, then the total power of the second energy supply is maintained; If the thermal field control state is in a state to be adjusted, then the total power of the second energy supply is adjusted according to the state to be adjusted until the thermal field control state reaches the stable and qualified state.

10. A downhole dynamic thermal field control device, characterized in that, include: The first acquisition module is used to acquire the initial temperature field data of the target downhole wellbore; The second acquisition module is used to acquire a pre-constructed formation fluid coupling model; The calculation module is used to calculate the total first energy supply power of each heating section in the target well based on the initial temperature field data and the formation fluid coupling model. The first processing module is used to perform segmented heating of each heating section of the target well based on the first total energy supply power, so as to obtain the first real-time temperature data of each heating section of the target well. The first determining module is used to determine the corresponding first downhole thermal field uniformity based on the first real-time temperature data. The second determining module is used to determine the corresponding thermal field control state based on the first downhole thermal field uniformity and the first real-time temperature data. The second processing module is used to maintain the first total energy supply power of each heating section of the target well if the thermal field control state is a stable and qualified state. The third processing module is used to adjust the first total energy supply power if the thermal field control state is in an adjustment state, so as to obtain the adjusted second total energy supply power.

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