A wellhead device for an open coaxial casing heat exchange system

Abstract

The present application relates to an open coaxial casing heat exchange system wellhead device, which includes a well seat installed on a geothermal well, a longitudinal pipe for water outlet coaxially arranged in the well seat, a plurality of water inlet pipes arranged in an array along the center of the longitudinal pipe, a first hanger arranged at the bottom end of the longitudinal pipe, and an inner pipe detachably connected to the end of the first hanger away from the longitudinal channel. The present application has the effect of making the wellhead device fix the inner pipe more stably.

Description

Technical Field

[0001] The present application relates to the technical field of geothermal collection, and in particular to a wellhead device of an open coaxial casing heat exchange system. Background Art

[0002] The large-scale development and utilization of geothermal heating has played an important role in clean winter heating in northern regions and alleviating haze weather, and geothermal heating technology has become mature.

[0003] The development and utilization of medium-deep geothermal energy mainly uses coaxial heat exchange to extract geothermal water as a traditional heat extraction method. Coaxial heat exchange generally uses open coaxial casing heat exchange or closed coaxial casing heat exchange. During the construction of the open ground source heat pump system, the submersible pump needs to be lowered into the geothermal well and located below the dynamic water level. The submersible pump is installed in the inner pipe, and the lower end of the inner pipe goes deep into the geothermal well. The outer coaxial sleeve of the inner pipe is connected with a casing. The submersible pump pumps the hot water from the geothermal well out of the geothermal well through the inner pipe and then passes it into the heat pump unit for use. After the heat pump unit absorbs heat, the water temperature decreases, and it flows into the geothermal well through the gap between the casing and the inner pipe and is reheated by geothermal heat.

[0004] With respect to the above-mentioned related technologies, the inventors found that the related technologies all require that the inner pipe, casing and submersible pump need to be fixed at the wellhead of the geothermal well by a wellhead device. Since the geothermal well is deep, the length of the inner pipe and casing is generally designed to be longer. In addition, with the submersible pump, the wellhead device used to fix the inner pipe bears a heavier weight. However, the fixing stability of the related wellhead device on the inner pipe is poor, so that the wellhead device needs to be frequently maintained or replaced, and is more cumbersome to use. Summary of the invention

[0005] In order to make the fixation of the wellhead device to the inner pipe more stable, the present application provides an open coaxial casing heat exchange system wellhead device.

[0006] The present application provides an open coaxial casing heat exchange system wellhead device adopts the following technical solution:

[0007] An open coaxial casing heat exchange system wellhead device comprises a well seat, a longitudinal pipe for water outlet is coaxially arranged in the well seat, a plurality of water inlet pipes are also arranged in the well seat, and the plurality of water inlet pipes are arranged in an array along the center of the longitudinal pipe;

[0008] A first hanger is arranged at the bottom end of the longitudinal pipeline, and an inner pipe is detachably connected to the end of the first hanger away from the longitudinal channel.

[0009] By adopting the above technical solution, the hot water in the geothermal well passes through the inner pipe and is finally discharged from the geothermal well through the longitudinal pipe, and then the used and cooled water flows back into the geothermal well through the water inlet pipe. There are several water inlet pipes arranged in an array along the center of the longitudinal pipe. The overall structure is compact, which can not only reduce the impact of the inflow of water on the inner pipe, making the well seat more stable in fixing the inner pipe, but also reduce the diameter of the water inlet pipe, reducing the weight of the large-diameter water inlet pipe on the well seat. At the same time, the setting of the first hanger can ensure the stability of the well seat fixing the inner pipe, and facilitate the staff to repair and replace it.

[0010] Preferably, the first hanger includes a connecting pipe coaxially fixed to the bottom end of the longitudinal pipe, the end of the connecting pipe facing away from the longitudinal pipe is connected to a receiving pipe, the end of the receiving pipe facing away from the connecting pipe is threadedly connected to a conversion joint, and the conversion joint is threadedly connected to the inner pipe.

[0011] By adopting the above technical solution, the conversion joint can stably fix the inner pipe on the receiving pipe, and the conversion joint can also be changed in size to be suitable for the installation of inner pipes of different sizes, thereby improving the overall adaptability of the wellhead device.

[0012] Preferably, a connecting flange is coaxially fixedly connected to the outer circumference of the connecting pipe, and a conversion connecting nut is coaxially sleeved on the outer circumference of the connecting flange. A limiting ring is extended at the upper end of the conversion connecting nut in the direction of its own axis, and the inner circumference of the limiting ring is abutted against the outer circumference of the connecting pipe. The connecting pipe is inserted into the inner circumference of the socket tube, and the outer circumference of the socket tube is threadedly connected to the inner circumference of the conversion connecting nut, and the end of the socket tube abuts against the side wall of the connecting flange.

[0013] By adopting the above technical solution, the inner tube is first fixed to the socket tube through the conversion joint, and then the socket tube is fixed to the connecting pipe by the flange and the connecting nut. The installation and fixation between the inner tube and the longitudinal pipeline is completed. The connection structure is simple and compact, and the installation is convenient. At the same time, the inner tube is fixed stably.

[0014] Preferably, an annular groove is provided on the outer circumferential surface of the connecting pipe, the annular groove is located on the outer circumferential surface of the connecting pipe inserted into the inner circumferential surface of the receiving pipe, and a sealing ring is embedded in the annular groove.

[0015] By adopting the above technical solution and setting the sealing ring, the sealing performance between the connecting pipe and the receiving pipe is improved, the leakage of hot water is reduced, thereby reducing the waste of heat and making the overall operation of the wellhead device more stable.

[0016] Preferably, an annular groove is opened in the well seat, the water inlet pipe is located at the lower side of the annular groove and is interconnected with the annular groove, and a water collector is connected on the outer periphery of the well seat, and the water collector is interconnected with the annular groove.

[0017] By adopting the above technical solution, the water collector collects the cooled and utilized water in the annular groove, and then enters the geothermal well through the water inlet pipe at the bottom of the annular groove. The setting of the annular groove can form a buffer space when the water enters the water inlet pipe, thereby reducing the vibration of the water inlet pipe caused by the high water pressure, reducing the vibration of the well seat, and further reducing the impact of the vibration of the well seat on the inner pipe, thereby improving the fixing stability of the well seat to the inner pipe.

[0018] Preferably, a thermal insulation layer is coaxially sleeved on the outer peripheral surface of the longitudinal pipe, and the thermal insulation layer is located between the annular groove and the longitudinal pipe.

[0019] By adopting the above technical solution and setting up the insulation layer, the influence of the water in the annular groove on the hot water in the longitudinal pipe can be reduced, and the heat loss of the hot water in the longitudinal pipe can also be reduced, thereby improving the insulation performance of the wellhead device and improving the utilization rate of heat.

[0020] Preferably, a cylindrical cavity is also opened in the well seat, and the cylindrical cavity is located at the lower side of the annular groove. The water inlet pipe is located in the cylindrical cavity, and the water inlet pipe is interconnected with the annular groove through a second hanger, and the well wall of the geothermal well is accommodated in the cylindrical cavity.

[0021] By adopting the above technical solution, the cylindrical cavity is set up so that a space barrier is formed between the water inlet pipe and the longitudinal pipe, and air is used to isolate the influence of the water in the water inlet pipe on the hot water in the longitudinal pipe; at the same time, because the well wall of the geothermal well is contained in the cylindrical cavity, the bottom of the well seat can abut on the ground, thereby reducing the pressure of the well seat on the well wall and improving the fixation and load-bearing capacity of the well seat itself. The second hanger is used to fix the water inlet pipe, so that there is a transition period before the water enters the water inlet pipe from the annular groove, thereby further reducing the influence of the flow of water on the water inlet pipe and reducing the generation of vibration. At the same time, the second hanger fixes the water inlet pipe more stably, reducing the shaking of the water inlet pipe.

[0022] Preferably, the second hanger includes a transition tube interconnected with the annular groove, the transition tube is coaxially arranged with the water inlet pipe, and the end of the transition tube facing away from the annular groove is coaxially fixed with a ferrule, the end of the water inlet pipe is inserted into the ferrule, and a clamping nut is sleeved on the outer circumferential surface of the water inlet pipe, and the clamping nut is threadedly connected to the outer circumferential surface of the ferrule.

[0023] By adopting the above technical solution, the water inlet pipe is inserted into the ferrule, and then the clamping nut is rotated relative to the ferrule. The clamping nut squeezes the ferrule so that the inner periphery of the ferrule is squeezed on the outer periphery of the water inlet pipe, thereby fixing the water inlet pipe on the adapter tube, with a compact structure and stable fixation.

[0024] Preferably, the well seat is also provided with optical fiber temperature monitoring equipment and automatic water level monitoring equipment.

[0025] By adopting the above technical solutions, the optical fiber temperature monitoring equipment can monitor the downhole temperature in real time, and the automatic water level monitoring equipment can detect the water pressure of the incoming water, thereby improving the safety and reliability of the wellhead device.

[0026] Preferably, a protective tube for passing an optical fiber temperature measurement and monitoring device is installed in the well seat, and the protective tube passes through the annular groove.

[0027] By adopting the above technical solution, the protective tube can protect the optical fiber, reduce the impact of the water in the annular groove and the water inlet pipe on the optical fiber, and thus further improve the reliability of the wellhead device.

[0028] In summary, this application includes the following beneficial technical effects:

[0029] 1. The setting of the first hanger and the second hanger can ensure the stability of the well seat to the inner pipe and the water inlet pipe, and facilitate the maintenance and replacement of the workers;

[0030] 2. There are several water inlet pipes arranged in an array along the center of the longitudinal pipe. The overall structure is compact, which can not only reduce the impact of the inflow of water on the inner pipe, making the fixation of the well seat to the inner pipe more stable, but also reduce the diameter of the water inlet pipe, reducing the weight of the large-diameter water inlet pipe on the well seat.

[0031] 3. The setting of the annular groove can form a buffer space when water enters the water inlet pipe, thereby reducing the vibration of the water inlet pipe caused by the high water pressure, reducing the vibration of the well seat, and further reducing the influence of the vibration of the well seat on the inner pipe, thereby improving the fixing stability of the well seat to the inner pipe; the setting of the cylindrical cavity forms a space barrier between the water inlet pipe and the longitudinal pipe, and uses air to isolate the influence of the water in the water inlet pipe on the hot water in the longitudinal pipe; at the same time, the opening of the annular groove and the cylindrical cavity can also reduce the dead weight of the well seat, thereby reducing the pressure of the well seat on the wellhead of the geothermal well, making the use of the wellhead device more stable, thereby improving the fixing stability of the well seat to the inner pipe;

[0032] 4. The optical fiber temperature monitoring equipment can monitor the downhole temperature in real time, while the automatic water level monitoring equipment can detect the water pressure of the incoming water, thus improving the safety and reliability of the wellhead device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a front structural sectional view of an embodiment of the present application.

[0034] Figure 2 It is a top view of an embodiment of the present application.

[0035] Figure 3 It is a side partial structural sectional view of an embodiment of the present application.

[0036] Figure 4 yes Figure 3 A partial enlarged schematic diagram of part A.

[0037] Figure 5 yes Figure 3 A partial enlarged schematic diagram of part B.

[0038] In the figure, 1, geothermal well; 11, annular groove; 12, cylindrical cavity; 13, insulation layer; 2, well seat; 21, optical fiber temperature monitoring equipment; 22, automatic water level monitoring equipment; 23, protective tube; 3, longitudinal pipeline; 31, flange; 4, water inlet pipe; 5, first hanger; 51, connecting pipe; 511, connecting flange; 512, annular groove; 5121, sealing ring; 52, receiving pipe; 53, conversion connecting nut; 531, limiting ring; 6, inner pipe; 7, second hanger; 71, transfer pipe; 72, ferrule; 73, clamping nut; 8, water collector; 9, conversion joint. DETAILED DESCRIPTION

[0039] The present application is further described in detail below in conjunction with the accompanying drawings.

[0040] Reference Figure 1 and Figure 2, is an open coaxial casing heat exchange system wellhead device disclosed in an embodiment of the present application, including a well seat 2 installed at the wellhead of a geothermal well 1, the cross-section of the well seat 2 is circular, and a longitudinal pipe 3 for water outlet is coaxially fixed in the well seat 2, the upper end of the longitudinal pipe 3 passes through the upper end of the well seat 2 and is integrally formed with a curved pipe section, and a flange 31 is fixed at the end of the curved pipe section, so that the longitudinal pipe 3 is easily connected to other water delivery pipes. The well seat 2 is provided with an optical fiber temperature measurement monitoring device 21 and an automatic water level monitoring device 22. The optical fiber temperature measurement monitoring device 21 can monitor the downhole temperature in real time, and the automatic water level monitoring device 22 can detect the water pressure of the inlet water, thereby improving the safety and reliability of the wellhead device. Two protective tubes 23 are also installed in the well seat 2 for protecting the optical fiber temperature measurement monitoring device 21 and the automatic water level monitoring device 22 respectively. A number of water inlet pipes 4 parallel to the longitudinal pipeline 3 are also installed in the well seat 2. The number of water inlet pipes 4 can be reasonably set according to the flow rate of the inlet water. In this embodiment, the number of water inlet pipes 4 is set to six. The six water inlet pipes 4 and the two protective tubes 23 are arranged in an array along the center of the longitudinal pipeline 3, and the diameter of the water inlet pipe 4 is smaller than the diameter of the longitudinal pipeline 3. The end of the water inlet pipe 4 passes through the bottom of the well seat 2 and extends below the water surface in the geothermal well 1 (not shown in the figure). A first hanger 5 is provided at the bottom end of the longitudinal pipeline 3, and the end of the first hanger 5 away from the longitudinal channel is detachably connected with an inner pipe 6.

[0041] Reference Figure 2 and Figure 3, an annular groove 11 and a cylindrical cavity 12 are sequentially provided in the well seat 2 from top to bottom, the annular groove 11 and the cylindrical cavity 12 are not connected, the length of the annular groove 11 is less than the length of the cylindrical cavity 12, and there is a wall thickness between the annular groove 11 and the longitudinal pipe 3, and an insulation layer 13 is filled between the inner circumference of the annular groove 11 and the longitudinal pipe 3, the insulation layer 13 is annularly arranged and surrounds the outer circumference of the longitudinal pipe 3, wherein the insulation layer 13 can be made of asbestos, or can be filled with other materials with excellent waterproof, light and pressure resistance according to the needs of the use environment of the wellhead device. Two protective tubes 23 are respectively located in the annular groove 11, and the two ends of the protective tube 23 pass through the well seat 2, the lower end of the protective tube 23 is connected to the cylindrical cavity 12, and the protective tube 23 can be completely sealed when the optical fiber temperature measurement monitoring equipment 21 and the water level automatic monitoring equipment 22 are installed in the protective tube 23. The cylindrical cavity 12 passes through the bottom of the well seat 2, and the diameter of the cylindrical cavity 12 is larger than the outer diameter of the wall of the geothermal well 1, so that the well seat 2 can be coaxially sleeved on the wall of the geothermal well 1, and the upper end of the wall of the geothermal well 1 abuts against the upper side wall of the cylindrical cavity 12 in the well seat 2, so that the wall of the geothermal well 1 can stably support the well seat 2, and the lower end of the well seat 2 abuts against the concrete floor, thereby improving the fixation and load-bearing performance of the well seat 2. The water inlet pipe 4 is located in the cylindrical cavity 12 and the geothermal well 1 and is interconnected with the annular groove 11 through the second hanger 7. The outer periphery of the well seat 2 is connected with a water collector 8, the axis of the water collector 8 is perpendicular to the axis of the well seat 2, and the water collector 8 is interconnected with the annular groove 11.

[0042] The hot water in the geothermal well 1 is powered by the pump and passes through the inner pipe 6 and finally discharged from the geothermal well 1 through the longitudinal pipe 3. Then, the used and cooled water enters the annular groove 11 through the water collector 8. After the water collector 8 collects the cooled and utilized water in the annular groove 11, it directly enters the water surface of the geothermal well 1 through the water inlet pipe 4 at the bottom of the annular groove 11. The annular groove 11 can form a buffer space before the water enters the water inlet pipe 4, thereby reducing the vibration of the water inlet pipe 4 due to the high water pressure, reducing the vibration of the well seat 2, and further reducing the influence of the vibration of the well seat 2 on the inner pipe 6, thereby improving the fixing stability of the well seat 2 to the inner pipe 6. The eight water inlet pipes 4 can not only effectively reduce the flow rate of water in the annular groove 11 entering the water inlet pipe 4, but also reduce the impact of the inflow of water on the inner pipe 6, making the fixation of the well seat 2 to the inner pipe 6 more stable, but also reduce the diameter of the water inlet pipe 4, and reduce the impact of the weight of the large-diameter water inlet pipe 4 on the well seat 2. The opening of the cylindrical cavity 12 can not only reduce the pressure of the well seat 2 on the geothermal well 1, but also be supported on the concrete floor, which can further enhance the fixation and load-bearing capacity of the well seat 2.

[0043] Reference Figure 2 and Figure 3The first hanger 5 includes a connecting pipe 51 coaxially fixed to the bottom end of the longitudinal pipe 3, and the end of the connecting pipe 51 away from the longitudinal pipe 3 is connected to a receiving pipe 52; the outer circumference of the connecting pipe 51 is coaxially fixed to a connecting flange 511, and the outer circumference of the connecting flange 511 is coaxially sleeved with a conversion connecting nut 53, and the upper end of the conversion connecting nut 53 extends in the direction of its own axis to form a limiting ring 531, and the inner circumference of the limiting ring 531 is close to the outer circumference of the connecting pipe 51, and the connecting pipe 51 is inserted into the inner circumference of the receiving pipe 52, and is connected to the connecting pipe 51. An annular groove 512 is formed on the outer circumferential surface of the connecting pipe 51 inserted into the receiving pipe 52, and a sealing ring 5121 is embedded in the annular groove 512. The sealing ring 5121 uses an O-shaped rubber sealing ring 5121 for hydraulic and pneumatic use to increase the sealing performance between the connecting pipe 51 and the receiving pipe 52. The outer circumferential surface of the receiving pipe 52 is threadedly connected to the inner circumferential surface of the conversion connecting nut 53. By screwing the conversion connecting nut 53, the end of the receiving pipe 52 can be abutted against the side wall of the connecting flange 511, thereby fixing the receiving pipe 52 on the connecting pipe 51.

[0044] Reference Figure 2 and Figure 3 In order to reduce the pressure of the inner tube 6 and the water inlet pipe 4 on the well seat 2, the inner tube 6 and the water inlet pipe 4 of the present application adopt a special insulation pipe, and can also adopt PE, PP and other materials that are easily available on the market. Since the weight of the inner tube 6 and the water inlet pipe 4 made of PE and PP materials is relatively small, and the density is less than water, the water inlet pipe 4 and the inner tube 6 deep below the water surface can further reduce their own gravity on the well seat 2 under the buoyancy of water, thereby improving the fixing stability of the well seat 2 to the inner tube 6 and the water inlet pipe 4. In order to fix the inner tube 6 on the receiving tube 52, a conversion joint 9 is installed at the end of the receiving tube 52 away from the connecting tube 51, and the inner circumference of the conversion joint 9 is threadedly connected to the outer circumference of the connecting tube 51, and the inner circumference of the conversion joint 9 is threadedly connected to the inner tube 6. And the conversion joint 9 can also be changed in size to be suitable for the installation of inner tubes 6 of different sizes, thereby improving the overall adaptability of the wellhead device. When the staff installs the inner tube 6 on the well seat 2, they first fix the inner tube 6 on the receiving tube 52 through the conversion joint 9, and then fix the receiving tube 52 on the connecting tube 51 by means of the flange and the connecting nut. The installation and fixation between the inner tube 6 and the longitudinal pipeline 3 is completed. The connection structure is simple and compact, and the installation is convenient. At the same time, the fixation of the inner tube 6 is stable.

[0045] Reference Figure 2 and Figure 4The second hanger 7 includes a transfer tube 71 whose upper end is interconnected with the annular groove 11. The transfer tube 71 is coaxially arranged with the water inlet pipe 4, and a clamping sleeve 72 is coaxially fixedly connected to the end of the transfer tube 71 away from the annular groove 11. The end of the water inlet pipe 4 is inserted into the clamping sleeve 72, and a clamping nut 73 is sleeved on the outer peripheral surface of the water inlet pipe 4. The clamping nut 73 is threadedly connected to the outer peripheral surface of the clamping sleeve 72. The water inlet pipe 4 is inserted into the clamping sleeve 72, and then the clamping nut 73 is rotated relative to the clamping sleeve 72. The clamping nut 73 squeezes the clamping sleeve 72, so that the inner periphery of the clamping sleeve 72 is squeezed on the outer peripheral surface of the water inlet pipe 4, thereby fixing the water inlet pipe 4 on the transfer tube 71, with a compact structure and stable fixation. The second hanger 7 is used to fix the water inlet pipe 4, so that there is a transition period before the water enters the water inlet pipe 4 from the annular groove 11, thereby further reducing the impact of the flow of water on the water inlet pipe 4 and reducing the generation of vibration. It can also limit the upward floating of the water inlet pipe 4 caused by the large buoyancy of the water in the geothermal well 1. The second hanger 7 fixes the water inlet pipe 4 stably and reduces the shaking of the water inlet pipe 4.

[0046] The implementation principle of the wellhead device of an open coaxial casing heat exchange system in the embodiment of the present application is as follows: in order to reduce the pressure of the inner tube 6 and the water inlet pipe 4 on the well seat 2, the inner tube 6 and the water inlet pipe 4 of the present application adopt a special insulation pipe, and can also adopt PE, PP and other materials that are easily available on the market. Since the inner tube 6 and the water inlet pipe 4 made of PE and PP materials are relatively light in weight and have a density lower than that of water, the water inlet pipe 4 and the inner tube 6 that are deep below the water surface can further reduce their own gravity on the well seat 2 under the buoyancy of the water, thereby improving the fixing stability of the well seat 2 on the inner tube 6 and the water inlet pipe 4; the design of the first hanger 5 and the second hanger 7 The arrangement can ensure the stability of the fixation of the inner pipe 6 and the water inlet pipe 4 by the well seat 2, and it is convenient for the staff to repair and replace them; the six water inlet pipes 4 are arranged in an array along the center of the longitudinal pipeline 3, and the overall structure is compact, which can not only reduce the impact of the inflow of water on the inner pipe 6, making the fixation of the inner pipe 6 by the well seat 2 more stable, but also reduce the diameter of the water inlet pipe 4, and reduce the impact of the weight of the large-diameter water inlet pipe 4 on the well seat 2; the optical fiber temperature measurement monitoring equipment 21 can monitor the downhole temperature in real time, and the automatic water level monitoring equipment 22 can detect the water pressure of the water inlet, thereby improving the safety and reliability of the wellhead device.

[0047] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An open coaxial casing heat exchange system wellhead device, comprising a well seat (2) installed on a geothermal well (1), characterized in that: A longitudinal pipe (3) for discharging water is coaxially arranged in the well seat (2), and a plurality of water inlet pipes (4) are also arranged in the well seat (2), and the plurality of water inlet pipes (4) are arranged in an array along the center of the longitudinal pipe (3); a first hanger (5) is arranged at the bottom end of the longitudinal pipe (3), and an end of the first hanger (5) away from the longitudinal channel is detachably connected to an inner pipe (6); the first hanger (5) comprises a connecting pipe (51) coaxially fixed to the bottom end of the longitudinal pipe (3), and an end of the connecting pipe (51) away from the longitudinal pipe (3) is connected to a receiving pipe (52). The end of the receiving pipe (52) facing away from the connecting pipe (51) is threadedly connected with a conversion joint (9), and the conversion joint (9) is threadedly connected to the inner pipe (6); the outer peripheral surface of the connecting pipe (51) is coaxially fixedly connected with a connecting flange (511), and the outer peripheral surface of the connecting flange (511) is coaxially sleeved with a conversion connection nut (53), and the upper end of the conversion connection nut (53) extends in the direction of its own axis to form a limiting ring (531), and the inner peripheral surface of the limiting ring (531) is in contact with the outer peripheral surface of the connecting pipe (51), and the connecting pipe (51) is inserted into the inner pipe (6). The inner circumference of the receiving tube (52) is threadedly connected to the inner circumference of the conversion connection nut (53), and the end of the receiving tube (52) abuts against the side wall of the connection flange (511); an annular groove (512) is provided on the outer circumference of the connecting tube (51), and the annular groove (512) is located on the outer circumference of the connecting tube (51) inserted into the inner circumference of the receiving tube (52), and a sealing ring (5121) is embedded in the annular groove (512); an annular groove (11) is provided in the well seat (2), and the water inlet pipe (4) is located in the well seat (2). The lower side of the annular groove (11) is connected to the annular groove (11), and the outer periphery of the well seat (2) is connected to a water collector (8), and the water collector (8) and the annular groove (11) are connected to each other; a cylindrical cavity (12) is also provided in the well seat (2), and the cylindrical cavity (12) is located at the lower side of the annular groove (11), and the water inlet pipe (4) is located in the cylindrical cavity (12), and the water inlet pipe (4) is connected to the annular groove (11) through a second hanger (7), and the well wall of the geothermal well (1) is accommodated in the cylindrical cavity (12).

2. The open coaxial casing heat exchange system wellhead device according to claim 1, characterized in that: A heat-insulating layer (13) is coaxially sleeved on the outer peripheral surface of the longitudinal pipe (3), and the heat-insulating layer (13) is located between the annular groove (11) and the longitudinal pipe (3).

3. The open coaxial casing heat exchange system wellhead device according to claim 1, characterized in that: The second hanger (7) comprises a transfer tube (71) interconnected with the annular groove (11); the transfer tube (71) is coaxially arranged with the water inlet pipe (4); and the end of the transfer tube (71) facing away from the annular groove (11) is coaxially fixed with a clamping sleeve (72); the end of the water inlet pipe (4) is inserted into the clamping sleeve (72); a clamping nut (73) is sleeved on the outer peripheral surface of the water inlet pipe (4); and the clamping nut (73) is threadedly connected to the outer peripheral surface of the clamping sleeve (72).

4. The open coaxial casing heat exchange system wellhead device according to claim 1, characterized in that: The well seat (2) is also provided with an optical fiber temperature measurement monitoring device (21) and an automatic water level monitoring device (22).

5. The open coaxial casing heat exchange system wellhead device according to claim 4, characterized in that: A protective tube (23) for an optical fiber temperature measurement and monitoring device (21) to pass through is installed in the well seat (2), and the protective tube (23) passes through the annular groove (11).

Images