Thermal performance testing device for horizontal section of deep U-shaped well

Abstract

The invention discloses a thermal performance testing device for a horizontal section of a deep U-shaped well, and belongs to the technical field of geothermal energy development and utilization. The device comprises a horizontal section targeting test assembly, a ground circulation regulation and control assembly, an on-way parameter acquisition assembly and a data processing and control assembly, the horizontal section targeting test assembly is embedded in the horizontal section, forms an independent test chamber through a test inner pipe and an end sealing piece, and is provided with a detachable grouped rock stratum module and a visual window; the ground circulation regulation and control assembly regulates and controls the temperature, the flow and the system pressure of circulation fluid. The on-way parameter acquisition assembly adopts a distributed optical fiber temperature measurement unit and an on-way pressure-temperature sensing unit to realize on-way parameter acquisition; and the data processing and control assembly is used for data acquisition, processing display and automatic regulation and control. The problems that an existing device is interfered by heat loss of a vertical well section and is poor in extreme environment adaptability are solved, the multi-lithology adaptation capacity is achieved, and accurate and targeted testing of the thermal performance of the horizontal section of the deep U-shaped well can be achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of geothermal energy development and utilization, specifically relating to a thermal performance testing device for the horizontal section of a deep U-shaped well. Background Technology

[0002] Geothermal energy, as a clean and renewable new energy source, plays a vital role in the transformation of the energy structure. Deep U-shaped wells, due to their unique structural advantages, have become a key carrier for geothermal energy development and utilization. The horizontal section, as the core area for heat exchange in deep U-shaped wells, directly determines the geothermal energy extraction efficiency and system operational stability through its thermal performance. Therefore, accurate testing of the thermal performance of the horizontal section of deep U-shaped wells is an important prerequisite for optimizing wellbore structural design and improving the efficiency of geothermal energy development.

[0003] In existing technologies, for example, Chinese invention patent CN109141952B discloses a performance testing device and method for medium-deep U-shaped well heat exchangers. This method employs an integrated testing mode of "vertical well section + horizontal section," using ground equipment such as distributed optical cable temperature measurement, water pumps, and chilled / hot water units to perform performance testing on the entire U-shaped well system. However, while such existing devices can achieve some heat exchange performance testing functions, they cannot meet the high-precision and targeted testing requirements of the horizontal section of deep U-shaped wells, exhibiting several significant drawbacks: (1) The testing system has an "integration" bias: Most existing devices adopt an integrated testing mode of "vertical well section + horizontal section" without thermal isolation design between the two; there is significant heat exchange between the vertical well section and the surface environment, and its heat loss will be directly added to the test data of the horizontal section, causing the true heat exchange performance of the horizontal section to be masked. For example, in the test of a 3000m deep well, the heat loss of the vertical well section can cause the test error of the heat exchange efficiency of the horizontal section to exceed 20%, which seriously affects the accuracy of the test results.

[0004] (2) Insufficient adaptability to extreme environments: Deep environments are characterized by high temperature and high pressure. The sealing structure and sensing elements of existing test devices are mostly designed based on shallow and medium-depth environments. Under deep working conditions, they are prone to sealing failure (such as pressure leakage caused by aging and deformation of ordinary rubber seals) and drift in sensing accuracy (such as the measurement error of conventional temperature sensors increasing to more than 1°C in environments above 200°C). They cannot meet the requirements of deep extreme test environments.

[0005] (3) Poor adaptability to multi-lithological strata: There are significant differences in the lithology of different strata (such as sandstone, granite, shale, etc.), and their thermal properties are different. However, the existing testing devices lack adaptability design for multi-lithological strata, making it difficult to accurately test the thermal performance of horizontal sections under heterogeneous strata, thus limiting the applicability of the devices.

[0006] In view of the shortcomings of the existing technologies, there is an urgent need for a thermal performance testing device that can achieve targeted isolation of horizontal sections, adapt to deep extreme environments, and have the ability to continuously and accurately collect data along the process, so as to fill the gap in the special testing technology for the horizontal section of deep U-shaped wells and provide reliable technical support for the efficient development of deep geothermal energy. Summary of the Invention

[0007] This invention provides a thermal performance testing device for the horizontal section of a deep U-shaped well, which solves the technical problems of current testing devices, such as overall deviation, insufficient adaptability to extreme environments, and poor adaptability to multi-lithological formations.

[0008] This invention provides a thermal performance testing device for the horizontal section of a deep U-shaped well, comprising: a horizontal section targeted testing component, which is embedded in the horizontal section of the deep U-shaped well to achieve thermal isolation between the horizontal section and the vertical section and to perform multi-lithological formation adaptation testing; a surface circulation control component, which is connected to the horizontal section targeted testing component via an insulated oil pipe to precisely control the temperature, flow rate, and system pressure of the circulating fluid; a friction parameter acquisition component, which is deployed on the horizontal section targeted testing component and the insulated oil pipe to acquire temperature and pressure data along the horizontal section; and a data processing and control component, which is electrically connected to the friction parameter acquisition component and the surface circulation control component respectively, for data acquisition, processing, display, and equipment control.

[0009] Preferably, the horizontal segment targeted testing assembly includes a test inner tube, end seals, and a centralizer; the length of the test inner tube is adapted to the length of the horizontal pipe to be tested, and its two ends are sealed by end seals. The two ends of the test inner tube are respectively provided with a fluid inlet and a fluid outlet. The fluid inlet and the fluid outlet are both connected to the ground circulation control assembly through insulated oil pipes, so that the test inner tube and the ground layer of the horizontal pipe form an independent test chamber; the centralizer is evenly distributed on the outer wall of the test inner tube to ensure that the test inner tube is centered in the horizontal pipe.

[0010] Preferably, the horizontal segment targeted testing component also includes a detachable grouped rock layer module, which is sleeved on the outside of the inner test tube and divided into multiple independent rock layer units along the length of the inner test tube. The length of a single rock layer unit is 5m, and adjacent rock layer units are detachably connected by a flange structure. Each rock stratum unit is provided with a corresponding visualization observation window. The visualization observation window is sealed with high-temperature and high-pressure resistant quartz glass, and a high-definition high-temperature resistant camera unit is fixedly installed inside the window.

[0011] Preferably, the end seal adopts a high-temperature and high-pressure resistant elastic sealing structure, is made of fluororubber reinforced composite material, has a sealing pressure of not less than 50MPa, and a temperature resistance range of -20℃ to 250℃. The inner wall of the end seal is interference-fitted with the inner tube of the test tube, and a temperature compensation layer is embedded inside. The flange connection of the detachable grouped rock strata module is equipped with a high-temperature and high-pressure resistant sealing gasket.

[0012] Preferably, the ground circulation control component includes a constant temperature storage tank, a high-pressure variable frequency water pump, a precision flow regulating valve, a high-precision electromagnetic flow meter, a check valve, a pressure gauge, a temperature gauge, and a return liquid treatment tank. The outlet of the constant temperature storage tank is connected to the inlet of the insulated oil pipe in sequence through a high-pressure variable frequency water pump, a precision flow regulating valve, a high-precision electromagnetic flow meter, and a check valve. The outlet of the insulated oil pipe is connected to the inlet of the return liquid treatment tank. The constant temperature liquid storage tank is equipped with an electric heating rod and a refrigeration unit, and the return liquid treatment tank is equipped with a filter layer and a temperature sensor.

[0013] Preferably, the along-path parameter acquisition component includes a distributed optical fiber temperature measurement unit and an along-path pressure-temperature sensing unit; the distributed optical fiber temperature measurement unit includes an armored temperature measuring optical fiber and an optical fiber demodulator, the armored temperature measuring optical fiber is embedded in the pipe wall along the axis of the test inner pipe, and its two ends extend to the ground and are connected to the optical fiber demodulator, for real-time acquisition of temperature distribution data along the horizontal section. The pressure-temperature sensing unit along the test tube includes multiple high-temperature and high-pressure sensors. These sensors are evenly distributed around the outer wall of the inner tube and spaced 2-5m apart along the length of the horizontal section. They are used to collect the formation pressure, formation temperature, and outer wall temperature of the inner tube at different locations in the horizontal section.

[0014] Preferably, the data processing and control components include a data acquisition module, a central control module, and a display output module. The data acquisition module is connected to a fiber optic demodulator, a pressure-temperature sensing unit along the flow path, a high-precision electromagnetic flowmeter, a pressure gauge, a thermometer, and a temperature sensor inside a constant-temperature storage tank, for centralized acquisition of test data such as temperature, pressure, and flow rate. The central control module is electrically connected to a high-pressure variable frequency water pump, a precision flow regulating valve, an electric heating rod, and a refrigeration unit, for adjusting the temperature, flow rate, and system pressure of the circulating fluid based on the acquired test data and preset test conditions. The display output module is used to display test data in real time and can export the data to a storage device, while also having a data anomaly alarm function.

[0015] Preferably, the inner layer of the insulated oil pipe is a high-temperature resistant stainless steel pipe, and the outer layer is an anti-corrosion and heat-insulating layer; the heat insulation performance of the insulated oil pipe meets the following requirements: when the ambient temperature is 25℃ and the fluid temperature inside the pipe is 150℃, the temperature of the outer surface of the pipe does not exceed 40℃.

[0016] Preferably, the high-precision electromagnetic flowmeter has a measurement range of 5~60 m³ / h and a measurement accuracy of ±0.2%.

[0017] Preferably, the high-temperature and high-pressure sensor of the pressure-temperature sensing unit is a quartz crystal sensor with a pressure measurement range of 0~100MPa and a temperature measurement range of -20℃~250℃, and measurement accuracies of ±0.1MPa and ±0.1℃, respectively.

[0018] The beneficial effects of this invention are: (1) Achieving precise horizontal section targeted testing: This invention sets up an independent horizontal section targeted testing component and uses end seals to form an independent testing chamber between the test inner tube and the horizontal wellbore, and thermally isolates it from the vertical well section; effectively eliminating the interference of heat loss in the vertical well section on the test data, and can obtain the true and high-precision thermal performance data of the horizontal section itself, providing a reliable basis for the study of heat exchange mechanism and efficiency optimization of the horizontal section of U-shaped well.

[0019] (2) Adaptable to deep extreme environments and multi-lithological strata: The key components of the device of this invention, such as the end seals, are made of high-temperature and high-pressure fluororubber reinforced composite materials with a sealing pressure of not less than 50MPa and a temperature range of -20℃ to 250℃. The internal temperature compensation layer can effectively offset the deformation of the sealing gap under high-temperature environment and ensure the sealing reliability under deep high-temperature and high-pressure conditions. The detachable grouped rock layer module is divided into multiple independent rock layer units along the length of the test inner tube. Adjacent units are detachably connected by a flange structure. Rock layer units of different lithologies can be quickly replaced according to test requirements to realize the adaptation test of multi-lithological strata and significantly improve the device's adaptability to operating conditions.

[0020] (3) Visual monitoring and precise data acquisition along the process to capture heat exchange patterns: The visual observation window opened on each rock stratum unit of the present invention is sealed with high-temperature and high-pressure resistant quartz glass and equipped with a high-definition high-temperature resistant camera unit inside. It can intuitively and in real time observe the dynamic process of heat exchange between the test tube and the rock stratum, which is convenient for accurately capturing the subtle changes and patterns in the heat exchange process. The parameter acquisition component along the process is combined with the distributed optical fiber temperature measurement unit and the pressure-temperature sensing unit along the process, which can realize the continuous acquisition of temperature distribution along the horizontal section and the accurate acquisition of pressure and temperature data at different locations, providing comprehensive and reliable data support for thermal performance analysis.

[0021] (4) Precise control of circulation parameters to ensure stability of test conditions: The ground circulation control component of this invention can achieve precise control of circulating fluid temperature, flow rate and system pressure through electric heating rods and refrigeration units in a constant temperature storage tank, high-pressure variable frequency water pump and precision flow regulating valve. Among them, the temperature control accuracy is high and the flow measurement range is 5~60m 3 The measurement accuracy reaches ±0.2% per hour, ensuring that the test process is carried out stably in strict accordance with the preset working conditions, thereby improving the repeatability and reliability of the test results.

[0022] (5) Intelligent data processing and security protection to improve the ease of operation: The data processing and control components of this invention realize the functions of centralized collection, processing, real-time display and export of test data, and have the function of data abnormality alarm. When parameters such as pressure and temperature exceed the set range, an alarm can be set in time and corresponding protection measures can be taken to reduce the test risk. The central control module can automatically adjust the operating status of related equipment according to the collected data, reduce manual intervention and improve the intelligence and convenience of device operation. Attached Figure Description

[0023] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram showing the positional relationship of the parameters acquisition components along the path in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the horizontal segment targeting test component according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the ground circulation control component according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the connection relationship of the data processing and control components in an embodiment of the present invention.

[0025] In the picture: 100 - Horizontal section targeted testing component; 110 - Test inner tube; 111 - Fluid inlet; 112 - Fluid outlet; 120 - End seal; 130 - Centralizer; 140 - Detachable grouped rock strata module; 141 - Visual observation window; 142 - High-definition high-temperature resistant camera unit; 200 - Ground circulation control component; 210 - Constant temperature storage tank; 211 - Electric heating rod; 212 - Refrigeration unit; 220 - High-pressure variable frequency water pump; 2 30 - Precision flow regulating valve; 240 - High-precision electromagnetic flow meter; 250 - Check valve; 260 - Pressure gauge; 270 - Thermometer; 280 - Return liquid treatment tank; 281 - Filter layer; 282 - Temperature sensor; 300 - Friction parameter acquisition component; 310 - Distributed fiber optic temperature measurement unit; 311 - Armored temperature measurement fiber optic cable; 320 - Friction pressure-temperature sensing unit; 400 - Data processing and control component; 500 - Insulated oil pipe. Detailed Implementation

[0026] The following are specific embodiments of the present invention described in conjunction with the accompanying drawings, further illustrating the technical solutions of the present invention. However, the present invention is not limited to these embodiments. Specific details, such as particular configurations and components, are provided in the following description merely to aid in a comprehensive understanding of the embodiments of the present invention. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Furthermore, for clarity and brevity, descriptions of known functions and structures have been omitted.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0028] like Figures 1-5 As shown in this embodiment, a thermal performance testing device for the horizontal section of a deep U-shaped well includes a horizontal section targeted testing component 100, a surface circulation control component 200, a friction parameter acquisition component 300, and a data processing and control component 400. The horizontal section targeted testing component 100 is embedded within the horizontal section of the deep U-shaped well to be tested, enabling thermal isolation between the horizontal and vertical sections and adaptability testing for multi-lithological formations. The surface circulation control component 200 is connected to the horizontal section targeted testing component 100 via an insulated oil pipe 500, providing circulating fluid for the test and precisely controlling the temperature, flow rate, and system pressure of the circulating fluid. The friction parameter acquisition component 300 is installed on the horizontal section targeted testing component 100 and the insulated oil pipe, used to collect various parameters during the testing process. The data processing and control component 400 is electrically connected to the friction parameter acquisition component 300 and the surface circulation control component 200, respectively, to realize data acquisition, processing, display, and control of the equipment.

[0029] The horizontal section targeted testing assembly 100 includes a test inner tube 110, end seals 120, a centralizer 130, and a detachable grouped rock formation module 140. The length of the test inner tube 110 is adapted to the length of the horizontal well section to be tested, for example, 20m in this embodiment. Both ends of the test inner tube 110 are sealed by the end seals 120 to achieve a sealed isolation from the wellbore annulus. The end seals 120 adopt a high-temperature and high-pressure resistant elastic sealing structure, and their material is fluororubber reinforced composite material. The sealing pressure is designed to be 60MPa, and the temperature resistance range is -20℃ to 250℃. The inner wall of the end seals 120 is interference-fitted with the test inner tube 110, and a temperature compensation layer is embedded inside, which can be made of expanded graphite material, to offset the deformation of the sealing gap caused by temperature changes under high-temperature environment and ensure long-term sealing reliability.

[0030] The inner test tube 110 has a fluid inlet 111 and a fluid outlet 112 at both ends. Both the fluid inlet 111 and the fluid outlet 112 are connected to the surface circulation control component 200 through an insulated oil pipe 500 to form a circulation loop. The centralizer 130 adopts an elastic centralizing structure and is installed every 2m along the outer wall of the horizontal test tube to ensure that the inner test tube 110 is centered in the horizontal pipe and avoid heat conduction interference caused by direct contact between the inner test tube and the well wall.

[0031] A detachable grouped rock strata module 140 is fitted onto the outside of the inner test tube 110, dividing it into multiple independent rock strata units along the length of the inner test tube 110. For example, in this embodiment, a 20m long test section is divided into 4 groups, with each rock strata unit being 5m long. Adjacent rock strata units are detachably connected via stainless steel flanges, with sealing gaskets at the flange connections. These gaskets are made of spiral wound metal to ensure a tight seal after connection. Each rock strata unit has a corresponding visual observation window 141, which measures 200mm × 150mm and is sealed with high-temperature and high-pressure resistant quartz glass (withstanding temperatures up to 300℃ and pressures up to 100MPa). A high-definition, high-temperature resistant camera unit is fixedly installed inside the window. It can use an industrial-grade high-temperature camera (1080P resolution, 25fps) to clearly capture subtle changes during the heat exchange process. The camera data is transmitted to the ground-based data processing and control unit 400 via a dedicated high-temperature resistant cable. This window allows for direct, real-time observation of the dynamic heat exchange process between the test inner tube 110 and the simulated rock formation or actual wellbore. By replacing the rock formation unit with different lithological materials (sandstone, granite, shale, etc.), the thermal performance under different lithological formation environments can be simulated or adapted for testing.

[0032] The ground circulation control component 200 includes a constant-temperature storage tank 210, a high-pressure variable frequency water pump 220, a precision flow regulating valve 230, a high-precision electromagnetic flowmeter 240, a check valve 250, a pressure gauge 260, a thermometer 270, and a return liquid treatment tank 280. The outlet of the constant-temperature storage tank 210 is connected sequentially to the high-pressure variable frequency water pump 220, the precision flow regulating valve 230, the high-precision electromagnetic flowmeter 240, and the check valve 250 via pipelines, ultimately connecting to the inlet end of the insulated oil pipe. The outlet end of the insulated oil pipe is connected to the inlet of the return liquid treatment tank 260. The constant-temperature storage tank 210 is equipped with an electric heating rod 211 and a refrigeration unit 212 for precisely controlling the temperature of the circulating fluid. In this embodiment, the constant temperature storage tank 210 has a volume of 5m³, the total power of the electric heating rod is 100kW, and the cooling capacity of the refrigeration unit is 50kW, enabling precise control of the circulating fluid temperature within the range of 20℃ to 200℃, with a control accuracy of ±0.5℃. The return liquid treatment tank 280 is equipped with a filter layer 281 and a temperature sensor 282, used to filter impurities in the circulating fluid and monitor the return liquid temperature.

[0033] The path parameter acquisition component 300 includes a distributed optical fiber temperature measurement unit 310 and a path pressure-temperature sensing unit 320. The distributed optical fiber temperature measurement unit 310 includes an armored temperature-measuring optical fiber 311 and an optical fiber demodulator. The armored temperature-measuring optical fiber 311 is embedded inside the tube wall along the axial direction of the inner test tube 110, with both ends extending to the ground and connected to the optical fiber demodulator. In this embodiment, the armored temperature-measuring optical fiber 311 uses single-mode fiber, with a temperature measurement accuracy of ±0.1℃, enabling real-time acquisition of continuous temperature distribution data along a 20m horizontal path. The friction-pressure-temperature sensing unit 320 includes multiple high-temperature and high-pressure resistant sensors. These sensors are quartz crystal sensors, which are evenly distributed around the outer wall of the inner test tube 110 and spaced 2-5m apart along the length of the horizontal section. In this embodiment, four quartz crystal sensors are arranged around the horizontal tube and the surrounding soil, with one sensor every 2m along the length, for a total of 10 sensors. Each quartz crystal sensor has a pressure measurement range of 0-100MPa and a temperature measurement range of -20℃-250℃, with measurement accuracies of ±0.1MPa and ±0.1℃, respectively. They are used to collect the formation pressure, formation temperature, and outer wall temperature of the inner test tube at different locations in the horizontal section.

[0034] The data processing and control component 400 includes a data acquisition module, a central control module, and a display output module. The data acquisition module is connected to a fiber optic demodulator, a high-temperature and high-pressure sensor, a high-precision electromagnetic flowmeter 240, a pressure gauge 260, a thermometer 270, and a temperature sensor 282 inside the constant-temperature storage tank 210, etc., for centralized acquisition of test data such as temperature, pressure, and flow rate. In this embodiment, the data acquisition module uses a high-speed data acquisition card with a sampling frequency of 10Hz to achieve synchronous acquisition of multi-channel data. The central control module is electrically connected to a high-pressure variable frequency water pump 220, a precision flow regulating valve 230, an electric heating rod 211 inside the constant-temperature storage tank 210, and a refrigeration unit 212, etc. In this embodiment, a PLC controller, model S7-1500, is used. Based on the acquired temperature, pressure, and flow rate data and preset test conditions, it automatically adjusts the speed of the high-pressure variable frequency water pump 220, the opening degree of the precision flow regulating valve 230, and the operating status of the electric heating rod 211 and the refrigeration unit 212, thereby precisely controlling the temperature, flow rate, and system pressure of the circulating fluid. The display output module uses an industrial touchscreen to display real-time temperature distribution curves, pressure change curves, and flow data along the pipeline. It can also export data to a storage device and features an alarm function for abnormal data. For example, in this embodiment, it is configured to automatically alarm and shut down for protection when the system pressure exceeds 70 MPa or the temperature exceeds 220°C.

[0035] The 500 insulated oil pipe has a high-temperature resistant stainless steel inner layer and an anti-corrosion insulation layer on the outer layer. Its insulation performance meets the following requirements: when the ambient temperature is 25℃ and the fluid temperature inside the pipe is 150℃, the temperature of the outer surface of the pipe does not exceed 40℃, effectively reducing the temperature loss of the circulating fluid during transportation and ensuring the temperature accuracy of the fluid when it reaches the horizontal section.

[0036] The working principle of this embodiment is as follows: According to the testing requirements, detachable grouped rock formation modules 140 of appropriate length and lithological configuration are selected and assembled on the outside of the test inner tube 110. The test inner tube 110 with centralizer 130 is lowered to the horizontal well section to be tested and sealed by end seal 120. The device is started, and the circulating fluid is heated or cooled to the set temperature in the constant temperature storage tank 210 in the surface circulation control component 200. Driven by the high-pressure variable frequency water pump 220, it is transported to the test inner tube 110 of the horizontal section targeted test component 100 through the precision flow regulating valve 230 and check valve 250. The fluid flows in the test inner tube 110 and exchanges heat with the outer formation (or simulated rock formation module). The distributed fiber optic temperature measurement unit 310 of the along-path parameter acquisition component 300 continuously collects the temperature distribution along the test inner tube, and the along-path pressure-temperature sensing unit 320 collects the pressure and temperature data at each point. After heat exchange, the fluid returns to the return liquid treatment tank 280 through the fluid outlet 112 and the insulated oil pipe. The data processing and control component 400 collects, displays, and records all data in real time, and automatically adjusts the operating parameters of the ground equipment according to preset values ​​to maintain stable test conditions. The heat exchange phenomenon can also be observed in real time through the visualization window 141 and the camera unit. By analyzing the collected data, the detailed thermal performance of this horizontal section under different operating conditions can be obtained.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] In the description of this application, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

Claims

1. A device for testing the thermal performance of the horizontal section of a deep U-shaped well, characterized in that, include: A horizontal section targeted testing component (100) is embedded in the horizontal section of a deep U-shaped well to achieve thermal isolation between the horizontal section and the vertical section and to perform multi-lithological formation adaptation testing. Ground circulation control component (200), which is connected to horizontal section target test component (100) through heat-insulated oil pipe (500) for precise control of temperature, flow rate and system pressure of circulating fluid; A friction parameter acquisition component (300) is installed on the horizontal section target test component (100) and the heat-insulated oil pipe (500) to collect temperature and pressure data along the horizontal section. The data processing and control component (400) is electrically connected to the along-the-path parameter acquisition component (300) and the ground circulation control component (200) respectively, and is used for data acquisition, processing, display and equipment control.

2. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 1, characterized in that, The horizontal segment targeted testing component (100) includes a test inner tube (110), an end seal (120), and a stabilizer (130). The length of the test inner tube (110) is adapted to the length of the horizontal pipeline to be tested, and its two ends are sealed by the end seal (120). The two ends of the test inner tube (110) are respectively provided with a fluid inlet (111) and a fluid outlet (112). The fluid inlet (111) and the fluid outlet (112) are both connected to the ground circulation control component (200) through a heat-insulated oil pipe (500), so that the test inner tube (110) and the horizontal pipeline stratum form an independent test chamber. The stabilizers (130) are evenly distributed on the outer wall of the test inner tube (110) to ensure that the test inner tube (110) is centered in the horizontal pipe.

3. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 2, characterized in that, The horizontal segment targeted test assembly (100) also includes a detachable grouped rock layer module (140), which is sleeved on the outside of the test inner tube (110) and divided into multiple independent rock layer units along the length of the test inner tube (110). The length of a single rock layer unit is 5m, and adjacent rock layer units are detachably connected by a flange structure. Each rock stratum unit is provided with a corresponding visualization observation window (141). The visualization observation window (141) is sealed with high-temperature and high-pressure resistant quartz glass, and a high-definition high-temperature resistant camera unit (142) is fixedly installed inside the window.

4. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 3, characterized in that, The end seal (120) adopts a high temperature and high pressure resistant elastic sealing structure, and the material is fluororubber reinforced composite material. The sealing pressure is not less than 50MPa and the temperature range is -20℃~250℃. The inner wall of the end seal (120) is press-fitted with the inner tube of the test tube (110), and a temperature compensation layer is embedded inside; The flange connection of the detachable group rock strata module (140) is equipped with a high-temperature and high-pressure resistant sealing gasket.

5. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 1, characterized in that, The ground circulation control component (200) includes a constant temperature storage tank (210), a high pressure variable frequency water pump (220), a precision flow regulating valve (230), a high precision electromagnetic flow meter (240), a check valve (250), a pressure gauge (260), a thermometer (270), and a return liquid treatment tank (280). The outlet of the constant temperature storage tank (210) is connected to the inlet end of the heat-insulated oil pipe (500) in sequence through a high-pressure variable frequency water pump (220), a precision flow regulating valve (230), a high-precision electromagnetic flow meter (240), and a check valve (250). The outlet end of the heat-insulated oil pipe (500) is connected to the inlet of the return liquid treatment tank (280). The constant temperature liquid storage tank (210) is equipped with an electric heating rod (211) and a refrigeration unit (212), and the return liquid treatment tank (280) is equipped with a filter layer (281) and a temperature sensor (282).

6. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 5, characterized in that, The friction parameter acquisition component (300) includes a distributed optical fiber temperature measurement unit (310) and a friction pressure-temperature sensing unit (320). The distributed optical fiber temperature measurement unit (310) includes an armored temperature measurement optical fiber (311) and an optical fiber demodulator. The armored temperature measurement optical fiber (311) is embedded in the inner wall of the test inner tube (110) along the axial direction, and its two ends extend to the ground and are connected to the optical fiber demodulator for real-time acquisition of temperature distribution data along the horizontal section. The pressure-temperature sensing unit (320) along the test tube includes multiple high-temperature and high-pressure sensors. The high-temperature and high-pressure sensors are evenly distributed around the outer wall of the test inner tube and are set at intervals of 2 to 5 m along the length of the horizontal section. They are used to collect the formation pressure, formation temperature and outer wall temperature of the test inner tube at different locations in the horizontal section.

7. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 6, characterized in that, The data processing and control component (400) includes a data acquisition module, a central control module, and a display output module; The data acquisition module is connected to the fiber optic demodulator, the pressure-temperature sensing unit (320) along the flow path, the high-precision electromagnetic flowmeter (240), the pressure gauge (260), the temperature gauge (270), and the temperature sensor (282) inside the constant temperature storage tank (210) for centralized acquisition of test data such as temperature, pressure, and flow rate; The central control module is electrically connected to the high-pressure variable frequency water pump (220), precision flow regulating valve (230), electric heating rod (211), and refrigeration unit (212), and is used to regulate the temperature, flow rate and system pressure of the circulating fluid according to the collected test data and preset test conditions. The display output module is used to display test data in real time and can export the data to a storage device. It also has a data anomaly alarm function.

8. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 1, characterized in that, The inner layer of the insulated oil pipe (500) is a high-temperature resistant stainless steel pipe, and the outer layer is an anti-corrosion and heat-insulating layer; the heat insulation performance of the insulated oil pipe (500) meets the following requirements: when the ambient temperature is 25℃ and the fluid temperature inside the pipe is 150℃, the temperature of the outer surface of the pipe does not exceed 40℃.

9. The thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 5, characterized in that, The high-precision electromagnetic flowmeter (240) has a measurement range of 5~60 m³ / h and a measurement accuracy of ±0.2%.

10. A thermal performance testing device for the horizontal section of a deep U-shaped well according to claim 6, characterized in that, The high-temperature and high-pressure sensor of the friction pressure-temperature sensing unit (320) is a quartz crystal sensor with a pressure measurement range of 0~100MPa and a temperature measurement range of -20℃~250℃, and measurement accuracies of ±0.1MPa and ±0.1℃, respectively.

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