Wellhead device for medium-deep geothermal underground heat exchange well

Abstract

The invention relates to the technical field of geothermal energy development, and discloses a wellhead device for a medium-deep geothermal underground heat exchange well, which comprises a wellhead main body, one side of the wellhead main body is provided with a petroleum casing pipe, and the other side of the wellhead main body is connected with a sealing gland; a heat exchange inner pipe is arranged in the petroleum casing pipe, and the heat exchange inner pipe is communicated with the water supply pipeline through a flange connecting disc; the elastic sealing ring is used for being deformed after being extruded to fill a gap between the sealing gland and the wellhead main body; the supporting device is arranged on one face of the sealing gland, and the vertical face of the supporting device makes contact with the water supply pipeline; and the water return pipeline communicates with the wellhead main body and is used for guiding the heat exchange water to flow out. The outer wall of the water supply pipeline is supported by the vertical surface of the supporting device, so that the fixing and supporting stability of the water supply pipeline and the heat exchange pipe can be enhanced, the possibility of deformation or damage of the heat exchange pipe caused by gravity or external force can be reduced, the service life of the heat exchange pipe is prolonged, and the long-term stability of the heat exchange effect is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of geothermal energy development, and in particular to a wellhead device for a mid-deep geothermal underground heat exchange well. Background Art

[0002] As the global demand for clean energy continues to increase, the development and utilization of mid-deep geothermal resources has attracted increasing attention. In the mid-deep geothermal downhole heat exchange technology, the wellhead device plays a vital role.

[0003] However, there are some problems with existing wellhead devices:

[0004] Poor sealing performance can easily lead to geothermal fluid leakage, affecting the environment and reducing energy efficiency;

[0005] During long-term operation, the fixation and support of the underground heat exchange tubes are not stable enough, which will cause the heat exchange tubes to deform or even be damaged, affecting the heat exchange effect and equipment life;

[0006] In addition, existing wellhead devices have poor adaptability to different working conditions and are difficult to meet complex geothermal exploitation conditions. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a wellhead device for medium-deep geothermal underground heat exchange wells, which solves the problems in the prior art such as poor sealing performance leading to leakage of geothermal fluid, unstable fixation and support of heat exchange tubes leading to deformation or damage of heat exchange tubes, and poor adaptability of the device that makes it difficult to meet complex geothermal exploitation conditions.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A wellhead device for a mid-deep geothermal underground heat exchange well, comprising:

[0009] The wellhead body has an oil casing on one side and a sealing gland on the other side;

[0010] A water supply pipeline passes through the sealing gland, a heat exchange inner tube is arranged in the oil casing, and the heat exchange inner tube is connected with the water supply pipeline through a flange connection plate;

[0011] An elastic sealing ring is located between the sealing gland and the wellhead body, and between the sealing gland and the water supply pipe, and is used to deform after being squeezed to fill the gap between the sealing gland and the wellhead body;

[0012] A supporting device, which is arranged on one side of the sealing gland, and the vertical surface of the supporting device is in contact with the water supply pipe;

[0013] The return water pipe is connected to the wellhead body and is used to guide the hot water to flow out.

[0014] Preferably, the supporting device is in the shape of a ring.

[0015] Preferably, the sealing gland and the wellhead body are connected by bolts, and the cross-section of the elastic sealing ring is set to be trapezoidal.

[0016] Preferably, a plurality of lifting rings are installed on the outer side of the middle portion of the top surface of the sealing gland, and the plurality of lifting rings are distributed in an equidistant star-shaped array with the sealing gland as the center.

[0017] Preferably, a connection point is provided at the bottom of the oil casing, and the oil casing is installed at the wellhead through the connection point.

[0018] Preferably, an exhaust valve is installed on one side of the middle portion of the sealing gland to exhaust the gas inside the oil casing.

[0019] Preferably, a flow controller and an ultrasonic heat meter are installed in the middle of the water supply pipe, and a pressure regulating valve is installed in the middle of the return water pipe.

[0020] Preferably, both sides of the middle of the water supply pipe and both sides of the middle of the return pipe are respectively provided with a thermometer interface and a pressure gauge interface, and the ultrasonic heat meter is located between the thermometer interface and the pressure gauge interface.

[0021] Preferably, the inner wall of the wellhead body is provided with a thermal insulation coating.

[0022] The present invention provides a wellhead device for a mid-deep geothermal underground heat exchange well. It has the following beneficial effects:

[0023] 1. The present invention can enhance the fixation and support stability of the water supply pipe and the heat exchange tube by utilizing the vertical surface of the support device to support the outer wall of the water supply pipe, thereby reducing the possibility of deformation or damage of the heat exchange tube due to gravity or external force, thereby extending the service life of the heat exchange tube and ensuring the long-term stability of the heat exchange effect.

[0024] 2. The present invention can effectively improve the sealing performance of the wellhead device by setting the elastic sealing ring to a trapezoidal shape, and the elastic sealing ring deforms after being squeezed to fill the gap between the sealing cover and the wellhead body, thereby reducing the risk of leakage of geothermal fluid, thereby protecting the environment and significantly improving energy utilization efficiency.

[0025] 3. The present invention sets a flow controller, an ultrasonic heat meter, a pressure regulating valve and an exhaust valve. The flow controller can accurately adjust the flow of the geothermal fluid in the water supply pipeline, the ultrasonic heat meter can monitor the heat, flow and temperature data of the fluid in real time, the pressure regulating valve can adjust the pressure inside the system according to the pressure change of the geothermal fluid, and the exhaust valve can discharge the gas accumulated in the oil casing in time, thereby effectively avoiding the instability of the system caused by abnormal flow, pressure or gas accumulation, thereby adapting to different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention;

[0027] Figure 2 It is a partial enlarged view of the wellhead of the present invention;

[0028] Figure 3 It is a top view of the sealing gland of the present invention.

[0029] Among them, 1. Wellhead body; 2. Flange connection plate; 3. Bolts; 4. Lifting ring; 5. Support device; 6. Sealing cover; 7. Elastic sealing ring; 8. Heat exchange inner tube; 9. Oil casing; 10. Connection point; 11. Pressure regulating valve; 12. Ultrasonic heat meter; 13. Flow controller; 14. Pressure gauge interface; 15. Thermometer interface; 16. Water supply pipeline; 17. Return pipeline; 18. Exhaust valve. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to better understand the present invention, the above contents are described in detail below in conjunction with specific embodiments.

[0032] Please refer to the attached Figure 1 -Attached Figure 3 The embodiment of the present invention provides a wellhead device for a mid-deep geothermal underground heat exchange well, including a wellhead body 1, one side of which is provided with an oil casing 9, and the other side is connected to a sealing gland 6; a water supply pipe 16, which runs through the sealing gland 6, and the oil casing 9 is provided with a heat exchange inner pipe 8, and the heat exchange inner pipe 8 is connected to the water supply pipe 16 through a flange connection plate 2; an elastic sealing ring 7, which is located between the sealing gland 6 and the wellhead body 1, and between the sealing gland 6 and the water supply pipe 16, and is used to deform after being squeezed to fill the gap between the sealing gland 6 and the wellhead body 1; a supporting device 5, which is provided on one side of the sealing gland 6, and the vertical surface of the supporting device 5 is in contact with the water supply pipe 16; a return water pipe 17, which is connected to the wellhead body 1, and is used to guide the hot water to flow out.

[0033] In this embodiment, the other side of the oil casing 9 is connected to the sealing gland 6, and the water supply pipe 16 passes through the sealing gland 6 and is connected to the heat exchange inner tube 8 through the flange connection plate 2. The deformation of the elastic sealing ring 7 after being compressed is used to fill the gap between the sealing gland 6 and the wellhead body 1, thereby forming a sealing structure. The return water pipe 17 can guide the water flow after heat exchange to complete the fluid circulation. The vertical surface of the support device 5 contacts the outer wall of the water supply pipe 16 to provide support to ensure the stability of the position of the water supply pipe 16 and the heat exchange inner tube 8. Therefore, the stability of the position of the water supply pipe 16 and the heat exchange inner tube 8 can be ensured, the stability of the fixation and support of the heat exchange tube is enhanced, and the possibility of deformation or damage of the heat exchange tube due to gravity or external force is reduced, thereby extending the service life of the heat exchange tube and ensuring the long-term stable operation and efficient heat exchange effect of the heat exchange system.

[0034] The supporting device 5 is in the shape of a ring. The inner wall of the wellhead body 1 is provided with a heat insulation coating.

[0035] In this embodiment, the support device 5 is annular, which can evenly distribute the support force, provide more stable support when in contact with the outer wall of the water supply pipe 16, further enhance the fixing effect of the heat exchange tube, reduce deformation or damage caused by uneven force, and thus extend the service life of the equipment. The inner wall of the wellhead body 1 is provided with a thermal insulation coating, which can effectively reduce the heat loss of geothermal fluid during the ascent process, improve the efficiency of thermal energy utilization, and further optimize the performance of the heat exchange system;

[0036] Among them, the thermal insulation coating can use ceramic microbead thermal insulation coating, which has high-efficiency thermal insulation performance, can effectively block heat conduction, reduce heat loss of geothermal fluid, and has excellent high temperature resistance. It can withstand temperatures up to 800°C and adapt to the high temperature environment of medium and deep geothermal wells. At the same time, it has strong corrosion resistance and can resist the erosion of acid and alkali components in geothermal fluids to ensure the long-term and stable use of the coating. It is environmentally friendly and safe, non-toxic and harmless, does not contain organic volatiles, is environmentally friendly, has strong adhesion, can be firmly bonded to the steel surface, is not easy to fall off, and is light in weight and does not increase the load on the wellhead body 1. It is an excellent performance thermal insulation material.

[0037] The sealing gland 6 and the wellhead body 1 are connected by bolts 3, and the cross section of the elastic sealing ring 7 is set to be trapezoidal.

[0038] The sealing gland 6 and the wellhead body 1 can be connected by using the bolts 3, and the distance between the two will be reduced after the connection. At this time, the elastic sealing ring 7 can be squeezed to deform it to fill the gap between the two, thereby achieving a sealing effect. By setting the cross-section of the elastic sealing ring 7 to a trapezoid, the trapezoidal structure can provide a larger contact area during the sealing process, so that it can form a tighter fit between the wellhead body 1 and the sealing gland 6, thereby significantly improving the sealing performance and preventing geothermal fluid leakage. At the same time, the trapezoidal shape can evenly disperse the pressure when under pressure, avoiding damage to the sealing ring due to stress concentration, further enhancing its durability and applicability, and is particularly suitable for geothermal wellhead devices under high temperature and high pressure environments, ensuring the safety and stability of system operation;

[0039] The elastic sealing ring 7 can use a fluororubber sealing ring because of its excellent high temperature resistance. It can withstand a working temperature of up to 200°C to 250°C for a long time, and can even withstand a high temperature of 300°C for a short time. It also has good corrosion resistance and can resist the erosion of common acidic and alkaline components in geothermal fluids. Its excellent compression resistance and elasticity ensure a stable sealing effect for a long time under high temperature and high pressure environments. Therefore, it is an ideal choice for sealing rings in geothermal wellhead devices.

[0040] A plurality of lifting rings 4 are installed on the outer middle of the top surface of the sealing gland 6, and the plurality of lifting rings 4 are distributed in an equidistant star array along the sealing gland 6. A connection point 10 is provided at the bottom of the oil casing 9, and the oil casing 9 is installed at the wellhead through the connection point 10.

[0041] In this embodiment, by installing the lifting ring 4 on the sealing gland 6, during maintenance, after removing the bolt 3, the sealing gland 6 can be lifted up by the lifting ring 4 to separate it from the wellhead body 1, thereby improving the convenience of subsequent maintenance, and the connection point 10 can provide an installation position for the oil casing 9.

[0042] An exhaust valve 18 is installed on one side of the middle of the sealing gland 6 to exhaust the gas inside the oil casing 9. A flow controller 13 and an ultrasonic heat meter 12 are installed in the middle of the water supply pipeline 16, and a pressure regulating valve 11 is installed in the middle of the return water pipeline 17. Thermometer interfaces 15 and pressure gauge interfaces 14 are respectively provided on both sides of the middle of the water supply pipeline 16 and the middle of the return water pipeline 17, and the ultrasonic heat meter 12 is located between the thermometer interface 15 and the pressure gauge interface 14.

[0043] In this embodiment, the exhaust valve 18 can discharge the gas accumulated inside the oil casing 9, thereby avoiding the impact of gas accumulation on the system operation; the flow controller 13 can adjust the geothermal fluid flow in the water supply pipe 16, the ultrasonic heat meter 12 can monitor the heat of the fluid in real time and display the flow and temperature data, and the pressure regulating valve 11 can adjust the pressure in the return pipe 17. Therefore, when the pressure is too high, the pressure in the wellhead body 1 can be reduced by the pressure regulating valve 11 and the flow controller 13, thereby ensuring the stability of the system operation pressure; and the thermometer interface 15 and the pressure gauge interface 14 can be installed with a thermometer and a pressure gauge to monitor the temperature and pressure of the fluid in real time, thereby ensuring the accuracy of the monitoring data, which is conducive to ensuring the safe operation of the device.

[0044] Working principle: When in use, first, install the wellhead body 1 at the wellhead position of the heat exchange well in the medium-deep geothermal well, fix the wellhead body 1 on the wellhead foundation through anchor bolts to ensure that the installation of the wellhead body 1 is firm and stable, then insert the heat exchange pipe into the wellhead body 1, put the elastic sealing ring 7 and the sealing gland 6 on the outside of the water supply pipe 16, and then connect the water supply pipe 16 with the heat exchange inner pipe 8 through the flange connection plate 2 and the bolt 3, and then adjust the position of the heat exchange pipe so that it is in the center position of the wellhead device, and then press the elastic sealing ring 7 between the wellhead body 1 and the sealing gland 6 through the bolt 3 to ensure the sealing effect. At this time, the support device 5 contacts the outer wall of the water supply pipe 16 to correct its position, thereby ensuring that the position of the heat exchange inner pipe 8 in the wellhead body 1 is accurate, so that it provides appropriate support force for the heat exchange pipe; finally, install the pressure regulating valve 11 on the return water pipe 17, and install the ultrasonic heat meter 12 and the flow controller 13 on the water supply pipe 16;

[0045] The ultrasonic heat meter 12 can monitor the heat of the heating fluid, and can also display the temperature and flow rate, and can transmit the data remotely by wireless transmission means, while the flow controller 13 adjusts the flow rate of the geothermal fluid in the water supply pipe 16, and the pressure regulating valve 11 can adjust the pressure inside the wellhead body 1 according to the pressure change of the geothermal fluid to keep the pressure of the wellhead body 1 stable, so as to ensure that the system operating parameters meet the set requirements, achieve efficient and stable heat exchange and system balance, and prevent damage to the equipment due to excessively high or low pressure, thereby ensuring the safety and stable operation of the system, and the flow rate of the geothermal fluid is controlled by the opening of the flow controller 13 to adapt to different mining conditions and heat exchange requirements. In addition, the water supply pipe 16 and the return pipe 17 of the wellhead device are respectively provided with a thermometer and a pressure gauge interface 14, so as to facilitate the installation of a thermometer and a pressure gauge as needed, thereby realizing real-time monitoring of the temperature and pressure of the geothermal fluid and ensuring the accuracy and safety of the system operation.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wellhead device for a medium-deep geothermal underground heat exchange well, characterized in that: include: A wellhead body (1) is provided with a petroleum casing (9) on one side and is connected to a sealing gland (6) on the other side; A water supply pipeline (16) passes through the sealing gland (6); a heat exchange inner tube (8) is arranged in the oil casing (9), and the heat exchange inner tube (8) is connected to the water supply pipeline (16) through a flange connection plate (2); An elastic sealing ring (7) is located between the sealing gland (6) and the wellhead body (1), and between the sealing gland (6) and the water supply pipe (16), and is used to deform after being squeezed to fill the gap between the sealing gland (6) and the wellhead body (1); A support device (5) is arranged on one side of the sealing gland (6), and a vertical surface of the support device (5) is in contact with the water supply pipe (16); A water return pipe (17) is connected to the wellhead body (1) and is used to guide the hot water to flow out.

2. A wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: The supporting device (5) is in the shape of a circular ring.

3. A wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: The sealing gland (6) and the wellhead body (1) are connected via bolts (3), and the cross section of the elastic sealing ring (7) is arranged to be trapezoidal.

4. A wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: A plurality of lifting rings (4) are installed on the outer side of the middle portion of the top surface of the sealing gland (6), and the plurality of lifting rings (4) are distributed in an equidistant star-shaped array along the sealing gland (6) as the center of the circle.

5. The wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: A connection point (10) is provided at the bottom of the oil casing (9), and the oil casing (9) is installed at the wellhead via the connection point (10).

6. A wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: An exhaust valve (18) is installed on one side of the middle of the sealing gland (6) for exhausting the gas inside the oil casing (9).

7. The wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: A flow controller (13) and an ultrasonic heat meter (12) are installed in the middle of the water supply pipe (16), and a pressure regulating valve (11) is installed in the middle of the water return pipe (17).

8. A wellhead device for a mid-deep geothermal underground heat exchange well according to claim 7, characterized in that: A thermometer interface (15) and a pressure gauge interface (14) are respectively provided on both sides of the middle of the water supply pipe (16) and both sides of the middle of the water return pipe (17), and the ultrasonic heat meter (12) is located between the thermometer interface (15) and the pressure gauge interface (14).

9. The wellhead device for a mid-deep geothermal underground heat exchange well according to claim 1, characterized in that: The inner wall of the wellhead body (1) is provided with a heat insulation coating.

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