A heat loss detection device and method for geothermal well insulation pipes

Abstract

This invention discloses a heat loss detection device and method for geothermal well insulation pipes, relating to the field of simulation detection technology. It includes an insulation pipe section and a simulated wellbore, with the simulated wellbore surrounding the insulation pipe section. An annular cavity for circulating cold fluid is formed between the simulated wellbore and the insulation pipe section. A plurality of detection probes are uniformly arranged along the axis of the insulation pipe section. By setting up a simulated wellbore, an annular cavity for circulating cold fluid is formed between it and the insulation pipe section. The insulation pipe section is filled with hot fluid, simulating the hot and cold fluids in a geothermal well. This provides a more realistic environment for detecting heat loss in the insulation pipe. The cold water temperature, hot water temperature, and cold water flow rate can all be set according to the actual geothermal well. The detection probes can monitor the hot fluid temperature in real time, thus obtaining more accurate heat loss data for the insulation pipe. Furthermore, it eliminates the need for on-site deployment, reducing costs.

Description

Technical Field

[0001] This invention relates to the field of simulation testing technology, and in particular to a heat loss detection device and method for geothermal well insulation pipes. Background Technology

[0002] Geothermal energy, as a clean energy source, has been extensively developed and utilized in recent years. The main form of utilization is the crude method of extracting underground hot water. The extracted water is then directly used or converted and reinjected into the formation. However, due to factors such as reinjection technology, formation pressure, and economic costs, the extracted water cannot be 100% reinjected, which exacerbates the aquifer funnel range and causes irreversible damage to the aquifer. Based on these problems, a new model of "extracting heat but not water" has been proposed for the utilization of geothermal energy resources—geothermal wells. This model effectively seals the aquifer that the borehole penetrates, injects cold water into the geothermal reservoir from the surface, and then pumps the hot water extracted from the geothermal energy to the surface for use through insulated pipes.

[0003] Currently, there are two types of geothermal wells: vertical single wells and U-shaped interconnected wells. Vertical single wells consist of a heat exchange pipe for the reservoir and a riser pipe for the formation above the reservoir. Cold water circulates outside the pipe string. To reduce heat exchange between the hot and cold water inside and outside the single well, insulated pipes with low thermal conductivity are required. U-shaped interconnected wells involve injecting cold water into the reservoir in one well and extracting hot water in another. Heat exchange occurs between the hot water in the extraction well and the formation, requiring the installation of insulated pipes as well. There are two main methods for assessing the heat loss of these insulated pipes: one is to calculate the heat loss through numerical simulation. This method has significant theoretical guidance, but it simplifies real-world conditions. Besides inherent factors such as formation and well depth, adjustable factors like the structure of the insulated pipe, the temperature and velocity of the cold fluid injected into the well, and the circulating hot fluid and its velocity within the insulated pipe also significantly affect the heat loss. This leads to a large discrepancy between the numerical simulation data and actual application. The second method involves direct application in geothermal wells, obtaining accurate data through practical application to guide other engineering wells. However, this method has high testing costs.

[0004] Therefore, there is an urgent need for a high-accuracy and low-cost device for detecting heat loss in geothermal well insulation pipes. Summary of the Invention

[0005] The purpose of this invention is to provide a heat loss detection device for geothermal well insulation pipes to solve the problems existing in the prior art. By setting up a simulated wellbore, an annular cavity for circulating cold fluid is formed between it and the insulation pipe section. The insulation pipe section is filled with hot fluid, simulating the hot and cold fluids in a geothermal well. This provides a more realistic application environment for detecting heat loss in the insulation pipe. The cold water temperature and flow rate can be set according to the actual geothermal well. The detection probe can check the temperature of the hot fluid in real time, thereby obtaining more accurate heat loss data of the insulation pipe. Moreover, it does not require on-site deployment, reducing costs.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a heat loss detection device for a geothermal well insulation pipe, comprising an insulation pipe section filled with hot fluid and a simulated well barrel, wherein the simulated well barrel is sleeved outside the insulation pipe section, and an annular cavity for circulating cold fluid is formed between the simulated well barrel and the insulation pipe section, wherein a plurality of detection probes for detecting the temperature of the hot fluid inside the insulation pipe section are uniformly arranged along its axis.

[0007] Preferably, both ends of the heat-insulating pipe section are sealed by an inlet cap and an outlet cap, respectively. The inlet cap is equipped with a hot fluid inlet valve, and the outlet cap is equipped with a hot fluid outlet valve. Both the inlet cap and the outlet cap are equipped with temperature sensors, and the temperature sensors are electrically connected to the detection probe.

[0008] Preferably, the detection probes, which are respectively connected to the temperature sensors at both ends, are symmetrically arranged on both sides of the center point of the inner cavity of the heat insulation pipe section.

[0009] Preferably, a sealing plate is provided at one end of the simulated well, a through hole is provided in the middle of the sealing plate, and an annular base supporting the water outlet sealing cover is provided on the inner wall of the sealing plate. The annular base is coaxially arranged with the through hole. A connecting flange is provided at the other end of the simulated well, and the through port in the middle of the flange is sealed to the heat insulation pipe section.

[0010] Preferably, the simulated wellbore is provided with a cold fluid inlet valve and a cold fluid outlet valve, the cold fluid inlet valve and the hot fluid inlet valve being located on the same side, and the cold fluid outlet valve and the hot fluid outlet valve being located on the same side.

[0011] Preferably, the heat-insulating pipe section is a double-walled heat-insulating pipe, and the inlet sealing cap and the outlet sealing cap are respectively threaded to the double-walled heat-insulating pipe.

[0012] Preferably, the inner tube of the double-walled heat insulation pipe is connected to the inlet sealing cap and the outlet sealing cap by insertion and sealing, respectively, and the outer tube of the double-walled heat insulation pipe is connected to the inlet sealing cap and the outlet sealing cap by thread.

[0013] Preferably, the temperature sensor is electrically connected to an external data processing terminal.

[0014] The present invention also provides a detection method for a heat loss detection device for geothermal well insulation pipes, comprising the following steps:

[0015] S1: Close the cold fluid outlet valve, open the cold fluid inlet valve, inject cold fluid into the simulated well, and after the cold fluid is full, open the cold fluid outlet valve and control the water flow of the cold fluid inlet valve and the cold fluid outlet valve to be the same to achieve cold fluid circulation.

[0016] S2: Inject hot fluid into the insulated pipe section through the hot fluid inlet valve and the hot fluid outlet valve, and close the hot fluid inlet valve and the hot fluid outlet valve after the injection is completed;

[0017] S3: The temperature sensor acquires the detection data from the detection probe and transmits it to an external data processing terminal for data analysis and processing to obtain the heat loss of the insulation pipe section.

[0018] Preferably, in step S3, the temperature sensor records the detection data of the detection probe every 10 seconds. After the cold fluid circulation ends, the external data processing terminal averages the multiple detection data in each time period.

[0019] The present invention achieves the following technical effects compared to the prior art:

[0020] 1. In this invention, a simulated wellbore is set up to form an annular cavity for circulating cold fluid between it and the insulated pipe section. The insulated pipe section is filled with hot fluid, simulating the hot and cold fluids in a geothermal well. This provides a more realistic application environment for detecting heat loss in the insulated pipe. The cold water temperature, hot water temperature, and cold water flow rate can all be set according to the actual geothermal well, improving the realism of the simulation. The detection probe can check the temperature of the hot fluid in real time, thereby obtaining more accurate heat loss data of the insulated pipe. Moreover, there is no need to deploy it on-site, reducing costs.

[0021] 2. In this invention, two temperature sensors are set up, and a detection probe is used to achieve uniform temperature measurement of the hot fluid. The average value of the measurement data is taken to improve the accuracy of temperature measurement. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the heat loss detection device for geothermal well insulation pipes according to the present invention;

[0024] The components include: 1. Insulated pipe section; 2. Simulated well shaft; 3. Detection probe; 4. Inlet sealing cover; 5. Outlet sealing cover; 6. Hot fluid inlet valve; 7. Hot fluid outlet valve; 8. Temperature sensor; 9. Sealing plate; 10. Annular base; 11. Connecting flange; 12. Cold fluid inlet valve; and 13. Cold fluid outlet valve. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The purpose of this invention is to provide a heat loss detection device for geothermal well insulation pipes to solve the problems existing in the prior art. By setting up a simulated wellbore, an annular cavity for circulating cold fluid is formed between it and the insulation pipe section. The insulation pipe section is filled with hot fluid, simulating the hot and cold fluids in a geothermal well. This provides a more realistic application environment for detecting heat loss in the insulation pipe. The cold water temperature and flow rate can be set according to the actual geothermal well. The detection probe can check the temperature of the hot fluid in real time, thereby obtaining more accurate heat loss data of the insulation pipe. Moreover, it does not require on-site deployment, reducing costs.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Please refer to the following: Figure 1As shown, a heat loss detection device for geothermal well insulation pipes is provided, including an insulation pipe section 1 and a simulated wellbore 2. The insulation pipe section 1 is the insulation pipe required for an actual geothermal well and is used to fill with hot fluid. The simulated wellbore 2 is sleeved outside the insulation pipe section 1. Preferably, the simulated wellbore 2 and the insulation pipe section 1 are coaxially arranged, forming an annular cavity between the simulated wellbore 2 and the insulation pipe section 1 for circulating cold fluid, simulating the circulation state of cold fluid in the geothermal well (the cold fluid is generally the ambient temperature in the well). A plurality of detection points for the insulation pipe are uniformly arranged along its axis inside the insulation pipe section 1. The detection probe 3 for the temperature of the hot fluid in section 1 is set up by setting up a simulated wellbore 2, which forms an annular cavity between the insulated pipe section 1 and the wellbore 2 for circulating cold fluid. The insulated pipe section 1 is filled with hot fluid, simulating the hot and cold fluids in the geothermal well. This provides a more realistic application environment for detecting the heat loss of the insulated pipe. The cold water temperature, hot water temperature, and cold water flow rate can all be set according to the actual geothermal well, improving the realism of the simulation. The detection probe 3 can check the temperature of the hot fluid in real time, thereby obtaining more accurate heat loss data of the insulated pipe. Moreover, it does not need to be deployed on-site, reducing costs.

[0029] To ensure the insulation pipe section 1 remains sealed during testing and to supply hot fluids of varying temperatures, both ends of the insulation pipe section 1 are sealed with an inlet cap 4 and an outlet cap 5, respectively. The inlet cap 4 is equipped with a hot fluid inlet valve 6, and the outlet cap 5 is equipped with a hot fluid outlet valve 7. Both the inlet cap 4 and the outlet cap 5 are equipped with temperature sensors 8, which are electrically connected to the detection probe 3. By using two temperature sensors 8 and the detection probe 3, uniform temperature measurement of the hot fluid is achieved, and the average value of the measurement data is taken to improve the accuracy of temperature measurement.

[0030] The detection probes 3, which are connected to the temperature sensors 8 at both ends, are symmetrically arranged on both sides of the center point of the inner cavity of the heat insulation pipe section 1. This improves the uniformity of the distribution of several detection probes 3 in the heat insulation pipe section 1, thereby improving the accuracy of temperature measurement. Specifically, the position of the detection probes 3 can be fixed by gluing support rods or other structures inside the heat insulation pipe section 1 and gluing the detection probes 3 to the support rods.

[0031] To facilitate the installation of the heat insulation pipe section 1, a sealing plate 9 is provided at one end of the simulated well barrel 2. The sealing plate 9 has a through hole in the middle. An annular base 10 supporting the water outlet sealing cover 5 is provided on the inner wall of the sealing plate 9. The annular base 10 is coaxially arranged with the through hole. A sealing strip is provided at the contact position between the annular base 10 and the heat insulation pipe section 1 to prevent the cold fluid in the annular cavity from flowing out. A connecting flange 11 is provided at the other end of the simulated well barrel 2. The through port in the middle of the flange is sealed to the heat insulation pipe section 1 by an annular sealing strip.

[0032] The simulated wellbore 2 is equipped with a cold fluid inlet valve 12 and a cold fluid outlet valve 13. The cold fluid inlet valve 12 and the hot fluid inlet valve 6 are located on the same side, and the cold fluid outlet valve 13 and the hot fluid outlet valve 7 are located on the same side.

[0033] In this embodiment, the heat insulation pipe section 1 is a double-wall heat insulation pipe, and the inlet sealing cap 4 and the outlet sealing cap 5 are respectively threaded to the double-wall heat insulation pipe.

[0034] The specific connection method between the inlet sealing cap 4 and the outlet sealing cap 5 and the double-wall heat insulation pipe is as follows: the inner tube of the double-wall heat insulation pipe is inserted and sealed to the inlet sealing cap 4 and the outlet sealing cap 5 respectively. The sealing connection adopts an embedded sealing ring, which is set on the outer wall of the corresponding insertion position of the inner tube. The inner thread of the outer tube of the double-wall heat insulation pipe is threaded and sealed to the inlet sealing cap 4 and the outlet sealing cap 5 respectively. The sealing connection adopts an embedded sealing ring, which is set on the inner wall surface of the corresponding threaded connection position of the outer tube.

[0035] Temperature sensor 8 is electrically connected to an external data processing terminal to transmit the collected data to the external data processing terminal for data processing.

[0036] The present invention also provides a detection method for a heat loss detection device for geothermal well insulation pipes, comprising the following steps:

[0037] S1: Adjust the temperature of the cold fluid according to the required simulated ambient temperature, close the cold fluid outlet valve 13, open the cold fluid inlet valve 12, inject cold fluid into the simulated well 2, and after the cold fluid is full, open the cold fluid outlet valve 13 and control the water flow of the cold fluid inlet valve 12 and the cold fluid outlet valve 13 to be the same to realize the circulation of the cold fluid.

[0038] S2: Adjust the temperature of the hot fluid according to the required simulated hot fluid temperature, and inject the hot fluid into the heat insulation pipe section 1 through the hot fluid inlet valve 6 and the hot fluid outlet valve 7. After the injection is completed, close the hot fluid inlet valve 6 and the hot fluid outlet valve 7.

[0039] S3: Temperature sensor 8 acquires the detection data from detection probe 3 and transmits it to an external data processing terminal for data analysis and processing to obtain the heat loss of insulation pipe section 1.

[0040] In step S3, the temperature sensor 8 records the detection data of the detection probe 3 every 10 seconds. After the cold fluid circulation ends, the external data processing terminal averages the multiple detection data in each time period.

[0041] Any adaptive changes made according to actual needs are within the scope of protection of this invention.

[0042] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0043] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A heat loss detection device for a geothermal well thermal isolation pipe, characterized by, The application relates to a heat-insulated pipe section filled with hot fluid and a simulated well hole, the simulated well hole is sleeved outside the heat-insulated pipe section, an annular cavity for circulating cold fluid is formed between the simulated well hole and the heat-insulated pipe section, a plurality of detection probes for detecting the temperature of the hot fluid in the heat-insulated pipe section are uniformly arranged along the axis of the heat-insulated pipe section; The two ends of the heat-insulated pipe section are respectively sealed by a water inlet sealing cover and a water outlet sealing cover, a hot fluid water inlet valve is arranged on the water inlet sealing cover, and a hot fluid water outlet valve is arranged on the water outlet sealing cover; The inner diameter of the water inlet sealing cover is larger than the inner diameter of the heat-insulated pipe section; One end of the simulated well hole is provided with a sealing plate, a through hole is arranged in the middle of the sealing plate, an annular base for supporting the water outlet sealing cover is arranged on the inner wall of the sealing plate, the annular base is coaxially arranged with the through hole, and a connecting flange is arranged at the other end of the simulated well hole; the middle through hole of the flange is sealingly connected with the heat-insulated pipe section.

2. The heat loss detection apparatus for a geothermal well thermal isolation pipe according to claim 1, characterized by, Temperature sensors are arranged on the water inlet sealing cover and the water outlet sealing cover, and the temperature sensors are electrically connected with the detection probes.

3. The heat loss detection apparatus for a geothermal well thermal isolation pipe according to claim 2, characterized by, The detection probes connected with the temperature sensors at the two ends are symmetrically arranged on both sides of the central point of the inner cavity of the heat-insulated pipe section.

4. The heat loss detection apparatus for a geothermal well thermal isolation pipe according to claim 2, characterized by, Cold fluid water inlet valves and cold fluid water outlet valves are arranged on the simulated well hole, the cold fluid water inlet valves are located on the same side as the hot fluid water inlet valves, and the cold fluid water outlet valves are located on the same side as the hot fluid water outlet valves.

5. The heat loss detection apparatus for a geothermal well thermal isolation pipe of claim 2, wherein, The heat-insulated pipe section is a double-wall heat-insulated pipe, and the water inlet sealing cover and the water outlet sealing cover are respectively threadedly connected with the double-wall heat-insulated pipe.

6. The heat loss detection apparatus for a geothermal well thermal isolation pipe of claim 5, wherein, The inner pipes of the double-wall heat-insulated pipe are respectively sealingly connected with the water inlet sealing cover and the water outlet sealing cover in a plug-in mode, and the outer pipes of the double-wall heat-insulated pipe are respectively sealingly connected with the water inlet sealing cover and the water outlet sealing cover in a threaded mode.

7. The heat loss detection apparatus for a geothermal well thermal isolation pipe of claim 2, wherein, The temperature sensors are electrically connected with external data processing terminals.

8. A detection method for a heat loss detection device for a geothermal energy well thermal isolation pipe, characterized in that, The application further discloses a data processing method. S1: closing the cold fluid water outlet valve, opening the cold fluid water inlet valve, injecting cold fluid into the simulated well hole, opening the cold fluid water outlet valve after the cold fluid is injected, and controlling the water flow of the cold fluid water inlet valve and the cold fluid water outlet valve to be the same, so that the cold fluid is circulated; S2: injecting hot fluid into the heat-insulated pipe section through the hot fluid water inlet valve and the hot fluid water outlet valve, closing the hot fluid water inlet valve and the hot fluid water outlet valve after the injection is completed; S3: the temperature sensors acquire detection data of the detection probes and transmit the detection data to external data processing terminals for data analysis and processing, so that the heat loss of the heat-insulated pipe section is obtained.

9. The detection method for the heat loss detection apparatus for geothermal energy well thermal insulation pipes according to claim 8, characterized by, In step S3, the temperature sensors record the detection data of the detection probes every 10 seconds, and the external data processing terminals take the average value of the multiple detection data in each time period after the cold fluid circulation is completed.

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